Economic Geology (1916) - Ries

ECONOMIC GEOLOGY
WORKS OF
PROF.
HEINRICH RIES
PUBLISHED BY
JOHN WILEY & SONS,
Inc.
Building Stones and Clay Products
A Handbook
for Architects, xiii+415 pages, 6 by

59 plates, including full-page half-tones and
20
figures in the text.
Cloth, 83.00 net.
maps,
9,
Clays: Their Occurrence, Properties and Uses

With Especial Reference to Those of the United
States. Second Edition, Revised, xix+554 pages,
6 by 9, 112 figures, 44 plates. Cloth, $5.00 net.
Economic Geology
Fourth Edition, Rewritten, xx+856 pages, 6 by
291 figures, 75 plates. S4.00 net.
AND LEIGHTOX
By RIES
the Clay
United Slates
History of
9,
Working Industry
in
the
By Prof. Hoinrich Ries, and Henry Leighton, Professor of Economic Geology, University of Pittsburgh. viii+270 pages, 6 by 9, illustrated. Cloth,
$2.50 net.
By RIES
AND WATSON
Engineering Geology
By
Prof. Heinrich Ries,
and Thomas
L.
Watson,
Professor of Economic Geology, University of Virand State Geologist of Virginia, xxvi+722

pages, 6 by 9. 249 figures in the text, and 104 plates,
comprising 175 figures. Cloth, $4.00 net.
ginia,
ECONOMIC GEOLOGY
BY
HEINRICH
RIES, A.M., PH.D.

lit
PROFESSOR OF GEOLOGY AT CORNELL UNIVERSITY
FOURTH EDITION, THOROUGHLY REVISED AND ENLARGED
NEW YORK
JOHN AVILEY & SONS,
LONDON: CHAPMAN & HALL,
1916
INO.
LIMITED
COPYRIGHT, 1905, 1907, 1910,
BY THE MACMILLAN
COMPANY
COPYRIGHT, 1916,
BY HEINRICH RIES
PRESS OF
BRAUNWORTH & CO.

BOOKBINDERS AND PRINTERS
BROOKLYN,
N. Y.
PREFACE TO FOURTH EDITION

THE continued advance in our knowledge of Economic Geology
has necessitated considerable revision for the new edition. In
addition, the author has, at the request of a number of teachers,
included a description of the more important Canadian mineral
deposits, as well as brief references to some of the well-known ones
of other countries.
While these additions to the text and
illustrations
have increased
the size of the book somewhat, the number of pages is not to be

taken as a gauge of the actual increase in size, for the reason that
over one hundred full-page illustrations, formerly bound as inserts,

are paged in with the text in the present edition.
The latest available statistics have been included, and unless
otherwise stated are taken from the United States Geological
Survey, and Canadian Department of Mines reports.

In a few cases, investigations to which reference might have been
made
have appeared too late to include them, but it

been possible to insert them in the reference list, and this
has been done.
The author takes pleasure here in acknowledging his deep indebtedness to Professor T. L. Watson of the University of Virhas
in the text
still
for reading and criticising the manuscript.

Thanks are
due to Dr. David White of the Geological Survey, for criticising the data contained in the chart on page 26, and to Mr. H. D.
ginia,
also
McCaskey
of the
same department,
for aid in obtaining statistical
data.
Acknowledgments for the loan of new illustrations are due to

Dr. R. G. McConnell, Deputy Minister of Mines, Canada; Dr.
E. Haanel, Director, Mines Branch, Canada; Professor E. C.
Jeffrey, Harvard University, Mr. F. W. DeWolf, State Geologist,
Illinois;
The Southern Railway Company; Mr.
F. C. Wallower,
Webb
The
City, Mo., and Mr. J. S. Hook, Cornell University.
latter also kindly took all of the photomicrographs made for this
edition.
CORNELL UNIVERSITY, ITHACA, N. Y.

June, 1916
iii
CONTENTS
PART
NONMETALLICS
I.
PAGE
1
CHAPTER
I.
II.
Coal
Petroleum, Natural Gas, and other Hydrocarbons
III. Building
70
138
Stones
170
IV. Clay
V. Limes and Calcareous Cements
187
VI. Salines and Associated Substances

VII.
210
244
Gypsum
VIII. Fertilizers.
260
284
IX. Abrasives
X. Minor Minerals.
Asbestos
Glass Sand
298
XI. Minor Minerals.
Graphite
Monazite
344
XII. Minor
Precious Stones
Minerals.
380
Wavellite
XIII. Underground Waters
PART
416
II.
ORE DEPOSITS
XIV. Ore Deposits
XV.
429
Iron Ores
502
XVI. Copper
568
XVII. Lead and Zinc

XVIII.
Silver
621
Lead Ores
XIX. Gold and
658
Silver
676
XX. Minor
Metals.
Aluminum, Manganese, Mercury
XXI. Minor
Metals.
Antimony
to
750
Vanadium
779
LIST OF ILLUSTRATIONS
PAGE
FIO.
1.
2.
Diagram showing changes occurring
in passage of vegetable tissue to
graphite
Section in Coal Measures of western Pennsylvania, showing fireclay
under coal beds

3.
4.
22
23
23
Section showing irregularities in coal seam

Section of faulted coal seam
due to an
5.
Section of coal bed, showing the development of a

overthrust roll
6.
Section across Coosa, Ala., coal field, showing folding and faulting
characteristic of southern end of Appalachian coal field
7.
Map of Pennsylvania anthracite field
split,
24
Sections in Pennsylvania anthracite field

Coal breaker in Pennsylvania anthracite region
10. Structure section in Tazewell County, east of Richlands, southwest
8.
9.
12.
13.
General structure section of the Richmond basin in the vicinity of

the James River
Section across Eastern Interior coal field
Shaft house and tipple, bituminous coal mine, Spring Valley, 111
Northern Interior coal field

Composite section showing structure of Lower Coal Measures of
Iowa
14. Generalized section of

15.
16.
Columnar
18.
Map showing distribution of different kinds of coal in Colorado

Map showing distribution of different kinds of coal in Wyoming ....
section of coal-bearing rocks in Oklahoma coal field

17. Generalized columnar section of the coal-bearing rocks of Arkansas.
19.
20.
21.
22.
23.
24.
25.
26.
29
30
30
31
34
Virginia coal field

11.
18
35
36
37
38
38
40
41
44
45
46
Geologic sections in southeastern part of Anthracite, Colo., sheet. ...
47
Map of Alaska, showing distribution of coal and coal-bearing rocks
48
Map showing coal areas of Nova Scotia
49
Map showing coal areas of Western Canada
Yearly production of anthracite and bituminous coal from 1856 to 1908 58
Diagram showing how plants fill depressions from the sides and top to
61
form a peat deposit
Sections of wells southeast of Humboldt, Kas
83
.
27. Sections of
deep wells in Claysville, Pa., quadrangle, showing irreguand number of the oil and gas sands
28. Section of anticlinal fold showing accumulation of gas, oil and water
"
29. Contour map of
sand," showing occurrence of gas on a structural
larity in thickness
dome in Oklahoma
84
87
88
vii
viii
PAGE
88
FIG.
30.
Gas pool coincident with a
structural terrace
31. Hypothetical cross-section through a volcanic neck in the oil fields of
Vera Cruz and Tamaulipas, Mexico
90
90
94
Diagrammatic section of sands in the central Appalachian region .... 95
98
Geologic section of Ohio-Indiana oil and gas fields
100
Map of Illinois showing distribution of oil fields
103
Map of California oil fields and pipe lines
North-south section, showing structure of western field of Los
104
Angeles district
106
Section of Spindle Top oil field near Beaumont, Tex
Generalized section from Paleozoic outcrop in Arkansas through
107
Caddo oil field, and Sour Lake to Galveston, Tex
32. Hypothetical section in same district as Fig. 31

33. Map showing lines of sections in Plate XI
34.
35.
36.
37.
38.
39.
40.
41.
Map
of Wyoming, showing approximately the areas underlain by

and gas
42. Section across portion of oil district of southwestern

of Alaska, showing areas in which oil or gas are
43.
44.
Map
Map of Mexico oil field
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
Map
Map
of asphalt
showing cleavage and bedding in slate

quarry with cleavage parallel to bedding
Map showing distribution of slate in the United States
Section showing formation of residual clay
Section of a sedimentary clay deposit
Geologic map of the Vlightberg area, Rondout, N. Y
58. Section in slate
60.
61.
62.
117
120
121
121
122
127
139
Photo-micrograph of a section of granite
140
Photo-micrograph of a section of diabase
142
Photo-micrograph of a section of quartzitic sandstone
Map showing distribution of crystalline rocks (mainly granites) in the
147
United States
152
Map showing marble areas of eastern United States
57. Section
59.
108
109
known to occur. 110
112
112
Wyoming
Mexico oil field

and bituminous rock deposits of the United States.
showing relation of grahamite fissure to anticlinal fold, in
Ritchie County, W. Va
Plan of Trinidad pitch lake
Section of gilsonite vein, Utah
Gilsonite mine at Dragon, Utah
Chart of oil production.
45. Section in
46.
oil
159
160
161
170
171
197
through the Vlightberg, showing position of natural

rock cement beds
198
63. Geologic sections
cement quarries at Utica, 111

198
cement belt of eastern Pennsylvania
199
66. Diagrammatic section two miles long extending northwest from Mar200
tin's Creek, N. J., showing overturned folds
67. Diagrammatic section five miles long, extending northwest from
200
Catasauqua
201
68. Map of United States, showing location of cement plants
204
69. Chart showing production of cement
64. Section in
65.
Map
of
ix
PAGE
MI;.
70. Figures representing the origin of
71.
dome
structure
growth
showing distribution of salt-producing areas
Map
by
crystalline
217
in the
United
218
States
72. Section
showing number and thickness of
localities in
salt
beds at different
New York state
73. Section across Hoist on
and
221
Saltville valleys,
ville and Plasterco, Va

74. Geologic section from Arkansas City to
occurrence of rock salt
midway between Salt222
Great Bend, Kas., showing
223
Map showing location of Petit Anse and other salt islands,
Louisiana 223
76. Section illustrating dome salt occurrence, under Cedar Lick, La.
224
77. Map showing borax deposits of the United States
234
75.
Furance Canon,
borate deposits
235
240
80.
248
81.
249
82. Section of gypsum deposit at Linden, N. Y
250
254
83. Map showing location of gypsum areas in Canada
84. Map showing phosphate areas of Florida
264
85. Map showing distribution of phosphates in Tennessee
267
86. Vertical section showing geologic position of Tennessee phosphates. 268
"
"
cutters
of brown phosphate
87. Sections showing development of
270
88. Map of parts of Idaho, Wyoming and Utah, showing localities of
273
Upper Carboniferous rocks containing phosphate beds
78. Cross-section of
79.
Calif.,
Map showing Owens and neighboring lakes of California

Map showing gypsum-producing localities of the United States
Map of New York, showing outcrop of gypsum-bearing formations.
89.
Columnar
sections showing position
phate beds
90. Section showing
and richness
of western phos-
274
structure
of
phosphate-bearing formations in
275
Wyoming
91. Section of Carboniferous strata
on north
side of Montpelier Creek,
Idaho
275
92. (a) Section of oolitic phosphate, Cokeville,
Wyo.
Tenn
(6)
Bigby limestone, brown phosphate district,

phosphate district
North-south section through Missouri and Statehouse Mountains,
showing folded character of novaculite and slate-bearing formations of Arkansas
Volcanic ash from Madison County, Mont
Section showing occurrence of corundum around border of dunite
mass
Map showing asbestos districts of the United States
93. Section in Lafferty Creek, Ark.,

94.
95.
96.
97.
98. Asbestos vein in serpentine
99. Geologic
100.
101.
Section of
Map
map
of
Vermont asbestos area
277
278
288
288
293
299
300
301
302
Quebec asbestos area

Photomicrograph of asbestos vein
Diagram showing asbestos and serpentine
of
304
306
in peridotite
of barite deposits of Appalachian states
103.
104. Barite veins in Potosi dolomite, southeastern Missouri
311
311
Mo
312
102.
Map
105. Barite deposit in residual clay near
Mineral Point,
x
FIG.
106.
Map
of Virginia,
107. Ideal sections in
showing location of worked areas of barite

Bennett barite mine, Pittsylvania County, Va.
Map
of barite veins near Lexington,

109. Sections of Kentucky barite vein
108.
110. Sketch section
showing relations
Ky
of barite
and limonite to under-
lying formations near Cartersville, Ga

111. Diatomaceous earth from Lompoc, Calif
Memphis mine group, along line ss of Plate XXXIV.

Map and sections of fluorspar deposits at Deming, N. Mex
Map showing principal graphite areas of northeastern states
Map of Bavarian graphite deposits
Map of part of California showing distribution of magnesite deposits
112. Section of
113.
114.
115.
116.
117. Plan
PAGE
312
313
314
314
315
319
328
330
347
350
358
magnesite veins and workings four miles northeast of
of
359
366
119. Section across pegmatite at Thorn Mountain mine, Macon Co., N.C. 366
120. Generalized cross-section of No. 1 or New York Mine, near Custer,
Porterville, Calif
118.
Map showing areas in North Carolina in which mica has been mined
S.
367
121. Section showing relations of ocher, quartzite
and
clay,
near Car-
Ga
372
showing area of monazite deposits of known commercial value
in southern Appalachian region
378
123. Map of Arkansas diamond area
381
124. Section in Arkansas diamond area
381
125. Section showing stratigraphy and structure from crest of Owl Creek
Mountains to Owl Creek, and relations of sulphur deposits near
397
Thermopolis, Wyo
398
126. Section in Sicilian sulphur deposits
398
127. Banded sulphur-bearing rock from Sicily
128. Plan of pyrite lenses at Sulphur Mines, Louisa County, Va., showing
401
pyrite (a) and crystalline schists (b)
129. Plan of pyrite lens (a), showing stringers of pyrite, interleaved with
schists (b) on hanging wall
402
130. Section of talc deposit near Tecopa, Calif
410
tersville,
122.
Map
131. Ideal section across a river valley, showing the position of ground
water and the undulations of the water table with reference to the
surface of the ground and bed rock

132. Section
showing
effect of tide
on
level of
416
417
water table
133. Geologic section of Atlantic coastal plain,
showing water-bearing
420
horizons
134. Section
from Black
Hills across
South Dakota, showing artesian
water circulations
420
431
448
450
135. Section of chromite in olivine partly altered to serpentine

136. Section through a contact-metamorphic zone and ore body
137. Section of garnetiferous limestone from Silver Bell, Ariz
138. Breccia of schist, in part replaced by sphalerite, and cemented
quartz
139.
by
462
Photo-micrograph of a section of quartz conglomerate, showing

463
replacement of quartz by pyrite
xi
463
Thin section showing replacement of hornblende by pyrite
Replacement vein in syenite rock, War Eagle Mine, Rossland, B. C. 464
142. J Photo-micrographs of thin sections of sulphide ore from Austin ville,
140.
141.
Va
143.1
465
468
144. Section of vein in Enterprise Mine, Rico, Colo

145. Section showing change in character of vein passing
from gneiss
470
porphyry
146. Tabulation of strikes of principal veins in Monte Cristo, Wash.,
470
district
471
147. Linked veins
Wisconsin zinc region 472
148. Gash vein with associated flats and pitches.
to
149. Section at Bonneterre, Mo.,
showing ore disseminated through lime473
stone
150
,
Sketches showing dimensions of an ore shoot
473
152. Section through Copper Queen orebody, Bisbee, Arizona

475
153.
showing distribution of hematite and magnetite deposits in
Map
505
United States
154. Geologic map of Adirondack region,
iron-ore deposits
155.
156.
157.
158.
159.
160.
161.
162.
163.
164.
165.
166.
167.
New
York, showing location of
506
507
508
Thin section of magnetite gneiss, Lyon Mountain, N. Y
Sections of the Old, 21-Bonanza-Joker, orebeds, Mineville, N. Y.
510
513
Geologic column of the Iron Springs, Utah, district
514
Map of a portion of the Iron Springs, Utah, district
Cross-section of Desert Mound contact deposit, Iron Springs, Utah 515
517
Photomicrograph of ore from Kiruna, Sweden
Section through Luossavara, near Kiruna, Sweden
518
523
Map of Iron Mountain, Wyo., titaniferous magnetite deposit
Section of titaniferous magnetite from Cumberland, R. 1
523
529
Map of Lake Superior iron regions
Sections of iron ore deposits in Marquette range
530
Generalized vertical section through Penokee-Gogebic ore deposit
and adjacent rocks
530
Map of Mineville, N. Y., iron ore district
168. Generalized vertical section through
Mesabi ore deposit and adja-
532
540
541
Outcrop of Clinton iron ore, Red Mountain, near Birmingham, Ala. 542
Map showing outcrop of Clinton ore formation in New York state. 544
545
Typical profile of slope on Red Mountain, Ala
Map showing distribution of limonite and siderite in the United
States
550
550
Map showing location of iron-ore deposits in Virginia
552
Geologic section showing position of iron-ore deposits in Virginia
Vertical section showing structure of the valley brown-ore deposits
at the Rich Hill mine, near Reed Island, Va
553
Section of fractured quartzite from residual limonite deposit, Pitts554
ville, Va
cent rocks
169.
170.
171.
172.
173.
174.
175.
176.
177.
178.
Map of eastern United States, showing areas of Clinton iron ore ....
Map showing outcrop of Clinton ore in Alabama
.
Xll
179. Section illustrating the formation of residual limonite in limestone

180. Section of Oriskany limonite deposit
181.
Thin section
182.
Diagram showing the production
183.
Map of Arizona,
of oolitic iron ore (minette) from Luxembourg

of iron ore, pig iron and steel in
the United States
showing location of more important mining
districts
184. Geologic sections of Bisbee, Ariz., district

185. Geologic section at Bisbee, Ariz
186. Geologic map of vicinity of Morenci, Ariz
187. Section in Morenci, Ariz., district
188. Photo-micrograph showing replacement in Clifton-Morenci ores.

189. Vertical section of ore body in Clifton-Morenci district
555
555
558
560
574
575
576
577
578
578
579
582
Photo-micrograph of altered porphyry containing grains of pyrite

Section showing replacement of limestone by pyrite and chalcopyrite,
584
Bingham Canon, Utah
192. Section of Ely, Nev., district
586
190.
191
map
193. Geologic
of
Copper Mountain
region, Prince of
Wales Island,
Alaska
194. Section through ore deposit at Phoenix, Brit. Col
195. Photo-micrograph of section of Phoenix ore
196. Section through Mother Lode ore body, Deadwood, Brit. Col.
of eastern part of Butte, Mont., district, showing ore veins
197.
.
588
590
591
591
Map
and geology
594
595
Longitudinal vertical projection of High Ore Vein, Butte, Mont .... 596
598
Plan of 500-foot level, Pennsylvania Mine, Butte, Mont
599
Geologic map of western half of Butte district
Vertical section showing ore body in schist, Mineral Creek, Ariz.,
Butte
198. Generalized cross-section of
199.
200.
201.
202.
district,
Montana
district
203. Geologic map of a portion of the Mineral Creek, Ariz., district.

204. Copper vein at Virgilina, Va
205. Generalized northwest-southeast section, including Isle
601
601
602
Royal and
Keweenaw Point
604
604
206. Section across Michigan copper belt
207. Map of a portion of Michigan copper district, showing strike of the
605
lodes
208. Section showing occurrence of amygdaloidal copper, Quincy Mine,
Mich
209. Plan of ore bodies, Ducktown, Tenn
210. Map of Carroll County, Va., pyrrhotite area
211.
Section of ore from Chestnut Yard, Va

showing distribution of lead and zinc ores in the United States
212.
Map
213.
Model
of Franklin ore
body
214. Plan of outcrop and workings of Sterling Eiii ore body

215. Ideal Section of Leadville, Colo., district
of Fig. 217, Tucson shaft, Leadville,
216. Vertical section along line
606
611
612
612
624
626
627
630
AB
633
Colo
217. Geologic plan of fifth level
Colo
and workings, Tucson
shaft, Leadville,
.634
xiii
PAGE
FIG.
Tucson shaft, Leadville, Colo

635
Bertha mine, Austinville, Va
638
220. Section showing replacement of limestone by sphalerite and galena,
218. Cavities in
Cambrian
quartzite,
219. Section of oxidized ore deposits,
221.
Austinville, Va
of Ozark region
639
639
Map
222. General west-east section through Joplin
and
St. Francis
Mountains,
Mo
223. General north-south section through Springfield
224. Generalized geologic section of Joplin district.
and
Mo.
Sedalia,
225. Photomicrograph of jasperoid

226. Four and one-half foot section showing occurrence of ore in
terre limestone,
Doe Run,
640
640
641
642
Bonne-
Mo
647
649
227. Section showing occurrence of lead and zinc ore in Wisconsin
228. Map of a portion of Wisconsin lead and zinc district, showing strike
underground contours of Galena limestone, and under650

ground workings
660
229. Map showing location of Cceur d' Alene, Idaho, district
662
230. Geologic map of Cceur d' Alene, Ido., district
231. Section of lead-silver vein, Cceur d' Alene, Ido
663
of crevices,
232.
Map
of
Nevada, showing location of more important mining
dis-
665
666
tricts
233. Geologic map of Tintic district, Utah

234. Section of ore body at Aspen, Col
669
670
236. Vein filling a fault fissure, Enterprise mine, Rico, Col
671
237. Map showing distribution of gold and silver ores in the United States 681
238. Map of California showing location of more important mining
districts
683
235.
Diagrammatic section across a northeasterly lode at Rico, Col
239. Section at Hedley, B. C., showing contact-metamorphic gold ore

bodies
688
Homestake belt at Lead, S. Dak

690
692
showing mineral deposits of Alaska
242. Sketch map of Douglas Island, Alaska
693
243. Cross-section through Alaska Treadwell mine on northern side of
694
Douglas Island
244. Map and section of portion of Mother Lode district, Calif
696
240. Section of
241.
Map
245. Section illustrating relations of auriferous quartz veins at

City, Calif
246.
Nevada
Map of Utah, showing location of more important mining districts
247. Typical section of siliceous gold ores, Black Hills, S.

248. Section at Mercur, Utah
249.
Map
250.
Map showing veins and porphyry
251.
Map of Colorado
Dak
showing approximate distribution of principal

gold regions of Colorado
698
700
701
701
silver, lead
and
702
dikes in the Silver Plume, Col. re,
gion
showing location of mining regions
252. Section across the Goldenville district,
Nova
Scotia
253. Transverse section of a part of the West Lake Mine,

254. Geologic section across the Goldfield, Nev., district
Mount
703
705
706
Uniake 707
708
xiv
PAGE
FIG.
255. Geologic map of Goldfield, Nev., district

709
256. Generalized columnar section of geological formations at Goldfield,
Nev
257.
Map showing outcrops of siliceous ledges east of
258. Geologic surface map of producing area of

259. East-west section through Mizpah shaft,
260. Section of
Goldfield,
710
712
715
716
718
Nev
Tonopah
Tonopah
Comstock Lode
261. Sections showing possible outline of the Cripple Creek volcanic

cone at the close of the volcanic epoch
719
720
262. Sections of vein at Cripple Creek, Colo
263. Vertical section through the Burns shaft, Portland Aline, Cripple
Creek, Colo
721
264. Geologic section across the northwest portion
of
the Telluride
724
726
732
752
752
quadrangle
265. Geologic map of Telluride district, Colorado
266. Generalized section of old placer with technical terms
267. Geologic map of Alabama-Georgia bauxite region
268. Section of bauxite deposit in Georgia- Alabama belt
269. Generalized cross-sections illustrating the geologic history of
the
Arkansas bauxite occurrences
755
762
762
manganese deposit, Crimora, Va

Map showing Georgia manganese areas
Section of Georgia manganese area
Section in Batesville, Ark., manganese region
Map of California mercury localities
Map showing Texas mercury region
270. Sections of
271.
272.
273.
274.
275.
276. Vertical section of California Hill, Terlingua,

277. Section of cinnabar vein in limestone
Tex
of limestone impregnated and replaced by cinnabar

showing chromic iron ore localities in Shasta County, Calif.
280. Section of Brown's chromic iron ore mine, Shasta County, Calif.
278.
Thin section
279.
Map
281.
Map of Cobalt-Porcupine-Sudbury region
282. Geologic map of Sudbury, Ont., nickel district

283. Geologic section of Sudbury, Ont., nickel district
284. Generalized section through productive part of Cobalt, Ont., area.
285. Section of calcite, and native silver, Cobalt, Ont
quantitative distribution
minerals associated with cassiterite
286.
Approximate
287.
Diagram
of
the
more important
812
to illustrate the genetic distribution and gradation of some

of the more common minerals in their association with cassiterite
only
288. Sketch
289.
764
766
773
774
775
775
776
790
791
797
798
798
801
802
map showing location of Carolina tin belt

Geologic map of Altenberg-Zinmvald tin district, Saxony
814
815
816
showing location and relations of rutile deposits in Nelson

820
County, Va
291. Plans and section in General Electric Company's mine, Nelson
821
County, Va
290.
Map
LIST OF PLATES
I.
1.
2.
II.
1.
2.
Mineral charcoal
11
Map showing coal fields of United States (colored)

Map of Pennsylvania, showing distribution of coals by fuel
25
11
structure
IV.
V.
27
33
33
39
ratios
VI.
Pit working near Milnesville,

2. View in Arkansas coal field
1.
1.
2.
IX.
1.
2.
X.
View
1.
known
to occur
oil field,
along line
View
1.
General view of Spindle Top oil field, Beaumont, Tex .... 105
General view of Trinidad asphalt lake
119
View of portion of Trinidad asphalt lake, showing digging
2.
Quarry
1.
Granite quarry, Hardwick, Vt

Quarry in volcanic tuff, north of Phoenix, Ariz
145
Quarry in limestone, Bedford, Ind

Marble quarry, Proctor, Vt
Marble quarry, Pickens County, Ga
151
2.
XVII.
XVIII.
1.
2.
XX.
XXI.
51
93
Generalized section in Appalachian
in
Los Angeles,
94
oil
field
94
field ....
123
of bituminous sandstone,
Slate quarry at Penrhyn,
101
101
Cal., oil field
operations
XIX.
51
2.
XIV.
XVI.
43
43
1.
XIII.
XV.
Kas
Subbituminous coal area, between Minera and

Cannel, Texas
Lignite seam, Williston, N. Dak
Beds of Subbituminous coal near Estevan, Sask
Coke ovens and tipple at Coleman, Alberta
Map showing areas in United States in which oil and gas
AB of Fig. 33
Northwest-southeast section in Pennsylvania
along line CD of Fig. 33
General view of Tuna Valley in Pennsylvania oil
2.
XII.
in
are
XI.
Pa
Geologic section from Kansas City to Topeka,
VII.
VIII.
3
7
7
Enlarged section of bituminous coal from Ohio

Enlarged section of cannel coal from Kentucky
Subbituminous coal from Marshall, Colo., showing
1.
2.
III.
Subbituminous coal
Bituminous coal
Santa Cruz, Calif
123
145
155
157
Pa
157
1.
slate quarry, Pawlet, Vt

Kaolin deposit in North Carolina
2.
Bank
Green
of sedimentary fire clays,
163
177
Woodbridge, N. J
177
xv
LIST OF PLATES
XVI
PLATE
XXII.
1.
2.
XXIII.
1.
2.
XXIV.
1.
2.
XXV.
1.
2.
XXVI.
XXVII.
195
Quarry of natural cement rock, Cumberland, Md
Natural cement rock quarry, Milwaukee, Wis
195
Limestone quarry in Lehigh cement district, Pa
203
203
Bog lime pit at Warners, N. Y
Interior view of salt mine, Livonia, N. Y
219
Borax mine, near Daggett, Calif
219
View in a Nova Scotia gypsum quarry, showing large
mass of anhydrite
245
245
Gypsum quarry, Linden, N. Y
1.
Gypsum
2.
View
1.
Rock phosphate mine near
quarry, Alabaster,
1.
Grindstone quarry, Tippecanoe,
2.
Corundum
1.
2.
1.
2.
XXXIV.
1.
2.
XXXVI.
1.
2.
XXXVII.
XXXVIII.
trench
brown phosphate around base
veir
between peridotite and
of hill ....
gneiss,
251
265
265
269
269
285
Corun-
Ga
285
289
General view of Asbestos quarry, Thetford Mines, Quebec 303
Granite dike cutting peridotite near asbestos veins, Thet305
ford, Que
305
Richardson feldspar mine near Godfrey, Ont
Stewart graphite mine, near Buckingham, Que
325
325
Lacey mica mine, Ontario
331
Map of portion of Kentucky fluorite district
357
Magnesite mine near Winchester, Calif
Hill,
View in Arkansas novaculite quarry
XXXI.
XXXV.
Ocala, Fla
Collar deposit of
XXX.
XXXIII.
2.
dum
XXXII.
251
N.
Phosphate beds, Montpelier, Ido

View in Tennessee, brown phosphate deposit, showing
cutters across strike of
XXIX.
Mich
in scythestone quarry, Pike Station,
1.
2.
XXVIII.
PAGE
FIG.
Network of magnesite veins in serpentine, same mine .... 357

361
View in glass-sand pit, on Severn River, Md
View showing sapphire workings, Yogo Gulch, Mont .... 361
415
1.
Section of an artesian basin
2.
Section illustrating conditions of flow in jointed crystal415

line rocks
3.
Section illustrating conditions of flow from solution pas415

sages in limestone
4.
Section illustrating conditions of flow from fissures in

415
stratified rocks overlain by drift
1.
Section illustrating conditions of flow from foliation and
419
schistosity planes
Section illustrating conditions of flow from vesicular trap 419
3. Section showing accumulation of water in stratified rocks
2.
with low intake
XXXIX.
1.
2.
XL.
1.
2.
XLI.
1.
2.
Specimen showing crustified structure

Steamboat Springs, Nev
Banded vein from Clausthal, Ger
Banded vein, Clausthal, Ger., showing wall rock

Vein specimen from Przibram, Bohemia:
Tin veinlets in granite, Altenberg, Saxony
419
439
439
467
467
469
469
LIST
PLATE
OF PLATES
xvii
PAGE
FFG.
XLII.
XLIII.
1.
2.
XLIV.
1.
2.
XLV.
Ponshed ore specimens from Burro Mountains, N. Mex.,

showing replacement of pyrite by chalcocite
View of open cut in magnetite, Mineville, N. Y
General view of magnetic separating plants and shaft
houses, Mineville, N. Y
View of iron mines at Kiruna, Sweden
View of iron mine at Gellivare, Sweden
General view of Mountain Iron Mine, Mesabi Range,
Minn
XL VI.
1.
2.
XLVII.
XLVIII.
XLIX.
LI.
1.
2.
1
district
district
Pit of residual limonite, Shelby, Ala

Old limonite pit, Ivanhoe, Va., showing pinnacled surface
of limestone which underlies ore-bearing clay
538
539
551
551
571
L^tah Copper Company's mine, Bingham, Utah

Smelter of Arizona Copper Company, Clifton, Ariz
581
583
583
Map showing distribution
L.
LIU.
Pa
map of western half of Birmingham,Ala.,

Geologic map of eastern half of Birmingham, Ala.,
1.
509
519
519
531
533
533
Geologic
2.
LII.
Iron mine, Soudan, Minn

View of limonite pit near Ironton,
483
509
of copper ores in the U.
View of Bingham Canon, Utah

View looking northeast from Eureka ore pit of the Nevada
Consolidated Copper Company, Ruth, Ely District,
Nevada
2.
LIV.
1.
2.
LV.
LVI.
LVII.
LVIII.
LX.
LXI.
587
587
Ariz., looking
589
589
Open cut, Mother Lode Mine, near Greenwood, B. C.
View of Anaconda group of mines, Butte, Mont
597
View from Houghton, Mich., looking towards Hancock. 607
.
1.
map of Franklin Furnace, N. J., and vicinity.

View from Carbonate Hill, Leadville, towards Iron Hill.
View from Carbonate Hill, overlooking California Gulch
and Leadville
View of valley at Austinville, Va
2.
Old oxidized ore workings at Austinville,
Geologic
1.
2.
LIX.
South end of Eureka ore pit, Ruth, Nev

View from Old Dominion open cut, Globe,
towards Miami
Va
Mo
in Joplin district near Webb City,

2. Workings in Disbrow mine, near Webb City,
1.
View
1.
View near Linden, Wisconsin, zinc mines

View looking north over Coeur d'Alene Mountains
2.
Mo
1
2.
LXIII.
1.
Nev
2.
Virginia City,
1.
Homestead Mills, hoists, and open cuts at Lead, S. Dak.

Kennedy mine on the Mother Lode, near Jackson, Calif.
Auriferous quartz veins in Maryland mine, Nevada City,
LXIV.
LXV.
General view of Rico, Colo

View of a portion of Mercur, Utah
Mill of Nickel Plate mine, Hedley, B.
2.
and horizontal plan of Kelly tunnel and

ated mine workings, Georgetown, Col
Vertical
687
687
689
697
697
Calif
LXVI.
634
637
637
643
643
661
661
667
667
'
LXII.
625
634
associ-
699
LIST OF PLATES
XV111
PLATE
PAGE
FIG.
LXVII
Plans of the principal levels of the January mine, Goldfield,
LXVIII.
1.
2.
LXIX.
LXX.
1.
2.
LXXI
LXXII
713
Bell
and
Commonwealth mines, Goldfield, Xev

713
General view in Cripple Creek district
717
View of Independence Mine and Battle Mountain,
723
Cripple Creek, Col
General view of region around Tonopah, Xev
723
2.
Telluride quadrangle
Hydraulic mining of auriferous gravel
An Alaskan placer deposit
1.
View
1.
2.
LXXV.
711
General columnar section of A, Ouray quadrangle; B,
LXXIII.
LXXIV.
Xev
Columbia Mountain, Goldfield, Xev

Ledge outcrop in dacite between the Blue
1.
2.
Crimora manganese mine, Virginia

of bauxite bank, Rock Run, Ala
Furnace for roasting Mercury ore, Terlingua, Tex
Old workings of tin mine, Altenberg, Saxony
Rutile mine, near Roseland,
Va
725
733
733
763
765
765
817
817
CHAPTER
COAL
There is such an intimate gradation between
Kinds of Coal.
vegetable accumulation now in process of formation and mineral
coal that it is generally admitted that coal is of vegetable origin.
By a series of slow changes (p. 17) the vegetable remains lose
water and gases, the carbon becomes concentrated, and the maTo the several stages
terials assume the appearance of coal.
of this process the following names are given: peat, lignite, subsemi bituminous,
bituminous, bituminous,
semianthracite,
and
anthracite.
This, which represents the first stage in coal

formed by the growth and decay of grasses, sphagnum,
Peat (119-130.)
formation, is
and other plants in moist places.
top downward
may
show:
(1)
A section in a peat bog from the

A layer of living plants; (2) a layer
of dead plant fibers, whose structure is clearly recognizable and

which grades into (3) a layer of fully formed peat, a dense, brownish
black mass, of more or less jellylike character, in which the vege-
table structure
The
is
often indistinct.
show the difference in composition of the

show that while during this change
They
following analyses
different layers.
also
the hydrogen and oxygen diminish, the carbon increases in proportion.
ANALYSES OF DIFFERENT LAYERS OF A PEAT BOG

MATERIAL
ECONOMIC GEOLOGY
This substance, also called brown coal, representLignite.

ing the second stage in coal formation, is usually brown or
sometimes yellowish in color, woody in texture, and has a brown
It burns readily, but with a long smoky flame, and
streak.
with lower heating power than the higher grades of coal. Because of the large amount of moisture it often dries out on
exposure to the
Lignite
is
air,
and rapidly disintegrates to a powdery mass.

and as mined is as a rule irregu-
distantly jointed,
larly slabby.
The lignites are usually restricted to the younger formations.

They are found in the various stages of the Cretaceous and Tertiary of the United States and Canada. Exceptionally they occur
beds as old as the Carboniferous, as in Russia (lla, p. 65).
in
Jet is a coal-black variety of lignite, with resinous luster and sufficient

It is obtained on
density to permit its being carved into small ornaments.
the Yorkshire coast of England, where a single seam produced 5180 pounds,
valued at $1250. According to Phillips, jet is simply a coniferous wood,

showing the characteristic structure under the microscope. ("Geology
still
of
England and Wales,"
p. 278.)
A grade intermediate
Subbituminous Coal cr Black Lignite.
between lignite and bituminous, and sometimes difficultly disIt is usually glossy black, and relatinguishable from these.
The
moisture content is commonly over 10
free
from
tively
joints.
from 8000 to 10,000 British thermal
value
and
the
calorific
cent
per
Campbell (is) has pointed out that it checks irreguon drying and when weathered splits parallel with the bedding, while bituminous coal shows a columnar cleavage (Plate I).
Bituminous Coal.
This represents the fourth stage in coal
formation. It is denser than the lignites, deep black, comparatively brittle, and breaks with cubical or sometimes conchoidal
fracture.
On superficial inspection it shows imperfect traces of
vegetable remains (Plate III); but in thin sections examined
under the microscope, traces of woody fiber, lycopod spores, etc.,
are commonly seen (Plate II).
Bituminous coal burns readily,
units (I2a).
larly
with a smoky flame of yellow color, but with greater heating

power than lignite. It does not disintegrate on exposure to
a r as readily as lignite does. Most bituminous coal is of earlier
age than
lignite;
but where the two occur
in the
same forma-
tion, as in parts of the West, the lignite is commonly in horizontal strata, while the bituminous coal occurs in areas of at
least slight disturbance.
PLATE
FIG.
1.
Subbituminous Coal, showing the irregular checking developed in drying.

(After Campbell, Econ. Geol., III.)
FIG. 2.
Bituminous Coal, showing prismatic structure.
(After Campbell.)
(3)
ECONOMIC GEOLOGY
When
and other gaseous constituents
freed of their volatile hydrocarbons
by heating to redness in a coke oven, many bituminous coals cake to a hard

mass called coke. Since all bituminous coals do not possess this characteristic, it is customary to divide these coals into coking and non-coking
coals.
The cause
is not clearly understood, and the chemical analappear to throw much light on the matter. It has been
suggested that the quality of coking may be influenced by the character of
the plant remains making up the coal. A proper determination of the coking
qualities of a coal usually involves a practical test, but it seems that the
coking qualities of a coal may be inferred with fair accuracy by its behavior
when ground in an agate mortar. Coals of good coking character stick to
the mortar, while those of opposite quality are easily brushed loose (28).
The coking value of a coal (20) seems to be indicated with fair accuracy
by the hydrogen-oxygen ratio, calculated on a moisture-free basis. Prac-
of ccking
ysis does not
TT
tically all coals
->58
with
per cent seem to possess coking qualities.
Most
TT
coals with
down
to 55
make coke
of
as low as 50 will coke, though the product
The hydrogen-oxygen
ratio
may
fail
some kind, and a few with
ratios
is rarely good.
as a guide in those coals under-
going anthracitization.
The formation of coke by natural processes
is
referred to
on
p. 5.
This is a compact variety of non-coking bituCannel Coal.

a dull luster and conchoidal fracture. Owing
with
minous coal,
to
its unusually high percentage of volatile hydrocarbons, upon

which its chief value depends, cannel coal ignites easily, burning
with a yellow flame, and when heated tends to decrepitate.
Microscopic examination of thin sections shows that it consists
largely of spores
(4a. 12a).
Semibituminous
This
Coal.
term was proposed by H. D.
to apply to those grades above bitumivolatile

matters
were between 12 and 18 per cent;
whose
nous,
while Frazer, in 1879, 2 used it to include those coals whose "fuel
"
ratios
(p. 19) ranged from 8 to 5.
Rogers as early as 1858
This term was employed by Rogers

Coal.
same time, and included those coals between bituminous
Semianthradte
at the
and anthracite having
less
than 10 per cent volatile matter.
Frazer later included under
it
those
coals
whose
fuel-ratios
ranged from 12 to 8.
Both terms persist, perhaps unfortunately, to the present
day, and are sometimes no doubt rather loosely used. Possibly
*
Geology of Pennsylvania, II: 983.

Second Pennsylvania Geological Survey, Kept.
MM:
148, 1879.
COAL
the disagreement among different people as to what shall be

included under these terms may be partly responsible for the
confusion.
Anthracite Coal.
This coal
is
black, hard,
and
brittle,
with
high luster and conchoidal fracture. It represents the last stage

in the formation of coal, and like bituminous coal, may show
Anthrajet-like bands, representing flattened stems or trunks.
has a lower percentage of volatile hydrocarbons and higher
On
percentage of fixed carbons than any of the other varieties.
cite
this account, it ignites
much
less easily
flame, but gives great heat.

The geological distribution
of
and burns with a short
anthracite
is
more
restricted
than that of bituminous coal, and in fact its occurrence is often

more or less intimately connected with dynamic disturbances.
This term is applied to natural
Carbonite or Natural Coke.
coke, which is formed by igneous rocks cutting across bituminous
As illustrative may be mentioned an occurrence in
coal seams.
"
dikes of igneous rocks ten feet in width have
central Utah, where
1
cut vertically across the coal bed, nine to sixteen feet thick, meta-
morphosing the coal into a coke-like substance to a distance of three

feet on either side.
The coal thus fused is distinctly columnar, the
columns standing perpendicular to the face of the dike; it has a
graphitic luster, but is not vesicular like artificial coke." Natural
coke is also found in New Mexico, Colorado, and Virginia.
The higher quantity of volatile matter in carbonite than artificial coke may be due to its having formed at some depth below the
surface, thus preventing the escape of the volatile matter, short
heating, or enrichment
by gases from the neighboring
ANALYSES OF NATURAL COKE
coal.
ECONOMIC GEOLOGY
An elementary analysis of coal

Proximate Analysis of Coal.
Therefore
is of comparatively little practical value.
proximate analyses are commonly employed, in which the probable method of combination of the elements is given. By the
proximate method the elements in the coal are grouped as
(see p. 18)
1
moisture, volatile matter, fixed carbon, ash, and sulphur.
The moisture can be driven off at 100 C. and is usually

The volatile matter was formerly termed
lignite.
carbons, but it is now clear that other substances also are
and
highest in peat
volatile
driven
red heat, and that the volatile matter of coals differs greatly in
hydrooff at
its
char-
acter. 2
The coals of the younger geological forrrations of the West have a large
proportion of carbon dioxide, carbon monoxide and water, and a correspondingly small proportion of hydrocarbons and tarry vapors. The Appalachian coals, on the other hand, contain much tarry vapor and hydrocarbon compounds.
The ash represents noncombustible mineral matter and bears no direct
relation to the kind of coal; and the same is true of sulphur, which is present
as an ingredient of pyrite or gypsum.
The value of coal for fuel or other purposes is determined mainly by the
relative amounts of its fuel constituents, viz., the volatile hydrocarbons
and the nonvolatile or
fixed carbons.
The
fuel value, or fuel ratio,
is
de-
termined by dividing the fixed carbon percentage by that of the volatile

hydrocarbons.
The fixed carbon of the coal burns with difficulty and is highest in the
The value of a coal for fuel purposes is determined
anthracite variety.
mainly by the relative amounts of its different constituents. Thus both
carbon and volatile hydrocarbons represent heating elements

former being the stronger. The maximum calorific value
seems to be reached when the volatile combustible matter is about 18 per
the fixed
in the coal, the
cent of the total combustible.
Coals with a high percentage of fixed carbon develop great heating

power, while those lower in fixed carbon and high in volatile hydrocarbons
lack in heating power, but are free burning.
Moisture is a nonessential constituent of coal. It not only displaces
so much combustible matter, but requires heat for its evaporation.
When
present in large amounts
it often causes the coal to disintegrate while

drying out. It ranges from perhaps 2 or 3 per cent in anthracite to 20 or
30 per cent in lignites.
Ash also displaces combustible matter, but otherwise it is in most cases
The clinkering of coal is commonly due to a high perinert impurity.

centage of fusible impurities in the ash, and for metallurgical work the
composition of the ash often has to be considered.
an
The proximate analysis, though apparently a simple operation, needs to be

See in this connection U. S. Geol.
carefully carried out to prevent variable results.
Surv., Prof. Pap. 48, I, and Bur. Mines, Tech. Pap. 8, 1913.
1
Bur. Mines, Bull.
1,
1910.
PLATE
FIG.
1.
II
Enlarged section of bituminous coal from Ohio. Crenulated bands are

Dark bands canneloid. White bodies, flattened
modified lignitic material.

spores.
FIG.
2.
(E. C. Jeffrey, photn.)
Enlarged section of cannel coal from Kentucky.
bands, wood.
White
bodies, flattened spores.
Light undulating
(E. C. Jeffrey, photo.)

(7)
ECONOMIC GEOLOGY
E>
H
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COAL
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ECONOMIC GEOLOGY
10
The
following analyses will also serve
to illustrate the
the ash:
ASH ANALYSES
composition of
PLATE
FIG.
a.
Subbituminous Coal from Marshall, Colo.
Jet-black Lenses represent Stems Flattened
b. Dull layers,
PIG.
1.
III
composed
2." Mineral Charcoal."
of
Decayed Wood,
(After White
by
Pressure.
Cuticles, Leaf Laminae, etc.
and Thiessen, Bur. Mines,
Bull. 38.)
(11)
ECONOMIC GEOLOGY
12
accumulation
origin)
of
transported
vegetable
matter
(allochthonous
As favoring the former theory we have the
perfect preservaplant remains, a condition unlikely to exist if the

material had been transported by streams, and the upright
trunks in coal, with roots extending into the under clay, the
tion of
many
supposedly representing the old soils or bottom muds

of the swamps in which the coal-forming plants grew.
It is true, however, that allochthonous coals may exist, because some formations have local coal deposits occurring as
latter
thin
wedges or
lenses,
derived from drifting plant
material,
with no roots penetrating the under clay. Indeed, some recent

writers, among them Jeffrey in the United States (4a, 246),
have argued most strongly in favor of this view, because of
the high spore content of
many
coals, wlrich could only
open water. The process

to be seen in modern lakes.
to accumulation in
but
its
analogue
is
is
be due
a slow one,
some deposits represent vegetable accumulaPossibly

tions in delta deposits, or in lacustrine beds, as in the case of
the Commentry fresh-water basin of France 1 or the Tertiaryalso
coals of the Frazer delta in British Columbia.
difficulty to
be overcome
is
the fact that
w hile
r
peat bogs
known covering
several square miles of area, they are not

comparable in size to the extensive coal deposits found in many
parts of the world.
Perhaps the most perfect resemblance to coal-forming con-
are
ditions is that now found in the Dismal Swamp of Virginia and

North Carolina, or the Great Sumatra Swamp. 2
In the former the area is very level, though with slight depressions in which there is either standing water or swamp conditions.
Indeed, there is such a general interference with free
drainage that the swamp areas are extensive, and vegetable
accumulations are taking place, a thickness of 8-12 feet of peat
having formed. There is, moreover, a general absence of sed-
iment.
In the latter swamp, which covers more than 80,000 hectares

(308.8 square miles) there is being deposited a high-grade peat
reaching a depth of 9 meters, and having only 6.39 per cent ash
in the dry fuel.
1
Stevenson, Ann., N. Y. Acad. Sci., XIX: 161, 1910.

Potonie, Entstehung der Steinkohle, 5th Ed.: 154, 1910.
COAL
If either of these areas
13
were submerged beneath the
sea, the
vegetable remains would be buried and a further step made

toward the formation of a coal bed. Re-elevation, making a
coastal plain,
bed above the

and again.
would permit the accumulation of another coal

first, and this process might be continued again
The evidence now
at
hand
indicates that the vast deposits
which represent the first stage in coal formations were

probably accumulated near tide level for the following reasons:
(1) Marine beds are often intercalated in the coal measures,
and are sometimes found overlying the coal; (2) brackish-water
molluscs are found in some of the rocks of the coal basins; (3)
the coal strata show a marked parallelism and a frequency of
of peat
salt-water invasion.
The coal-forming plants were of fresh-water character, and

the ingress of the sea was probably prevented either by the
presence of barrier ridges which kept out the salt water, or in
other cases a thick plant growth around the borders of the
swamps may have prevented any serious inflow of salt water.
The presumption
plants grew
of slight
is,
submergence
peneplain.
then, that in
in coastal or lacustrine
of a very
many
swamps developed
it
laid
down
in regions
mature and broadly extended
Some peat swamps were probably

but
cases the coal-forming
located
in
vast deltas,
such large vegetable accumulations took

in
salt
for
place
water,
although peat is known to be in process
"
of formation in salt marshes, White (I2a) says,
it does not seem
clear that coal with so large a percentage of mother of coal,
jet-like wood, etc., and with such pure carbonaceous matter,
that is, containing such a moderate percentage of ash, as the
coal in the Carboniferous of Illinois or Indiana, or that interbedded with marine or brackish water beds in Wyoming, was
is
doubtful
if
in estuaries flooded
by sea water."
however, sometimes made between: (1) limnetic coals, or those derived from plant remains accumulated in
fresh water; and (2) paralic coals, or those derived from plant
remains which collected in marshes near the sea border.
distinction
Character
of
is,
Organisms
Forming Coal
(4a,
12,
12o,
246)
1
Schuchert points to the persistent high sulphur content of the Mississippi
Valley coals as significant, for he states that this element is always present in
marine marshes and almost wanting in fresh-water ones.
ECONOMIC GEOLOGY
14
Microscopic study of different coals shows that the material is

composed of plant residues, consisting of the most resistant
of plants.
components
The
three important recognizable constituents are spores or

canneloid, modified wood or Kgnitoid, and to a less extent of
relatively unmodified carbonized
cf coal) (Plate III, Fig. 2).
wood
There
or mineral charcoal (mother

may also be resins, and resin
waxes.
Examination
of lignites
by White
(I2a)
showed them to con-
material, the interstices being filled with

debris of macerated plant refuse, comparable to many of the
sist chiefly of
woody
corresponding varieties of black amorphous peat, and composed

more resistant residue of plant parts, such as woody
of the
fragments, resinous substances, spore and pollen eximes, cuticles

and a cellulosic residue forming the binding substance.
Subbituminous coal shows greater density and higher concentration of resinous and cutinous substances, while stems,
trunks or branches appear as layers or lenses of dark black,
or jetty, glassy character,
and
characteristic luster (Plate III,
Fig. 1).
These same jetty layers show in bituminous coal (Plate III,

Fig. 1), while the dull lamina between represent plant debris.
Cannel coal is formed almost entirely of spore eximes, the
resins and cuticles forming only a small proportion of the mass.
These spores were formerly mistaken by some for algae, and it
is
now
recognized that neither the latter nor any homogeneous

jelly-like substance of this nature is present in
fundamental
bog-head, cannel, or any other coal.

Two stages may be recognized
Conditions cf Decomposition.
in the coalification process, viz., (a) the putrefaction stage, which
is
a biochemical process, and
stage, involving
the alteration or metamorphic
(6)
dynamo-chemical
action.
When dead
vegetable matter accumulates under water, it

does not remain unchanged, but undergoes a deoxygenation and
dehydrogenation process, which is accomplished by fermentation

or maceration in which minute plants (bacteria) and also ani-
As a result of this the plant tissues break down

to a greater or less degree, depending on the stage of decay.
The change may advance no further than to convert the mass
mals take part.
into
most
woody
or fibrous peat, or
it
may
of the plant structures, giving a
go far enough to obliterate

somewhat jelly-like black
COAL
15
which changes into the so-called amorphous coal. It is

highly probable that the process of decay had not advanced to
the same stage in all peats prior to their burial under sediment.
The decomposition of the original cellulose (CeHioOs) of the
plant tissue liberates substances such as CH4, as well as C02,
CO, H2O, etc. It seems probable that the jellification process
leads no further than peat, and that for the development of
peat,
the later stages dynamo-chemical changes are necessary.

While in peat beds the lower layers are under gentle pressure, so that a bed 1 foot thick, when buried under 15 or 20
feet of other peat layers,
may
be reduced to about
thickness, the real consolidation does not begin until

under a greater weight of sediment.
Indeed,
from
inch in
it is
buried
heat and pressure seem necessary for the change

bituminous coal, and long periods of time are
lignite to
apparently required for the slow changes that take place.

The process of change from lignite on is to be regarded
a dynamo-chemical one, which
chemical changes.
The
this
first
nature.
may
in
fact
as-
overlap the bio-
stage in the densification of peat under load is of

Occluded gases are expelled, liquid putrefaction
products forming the cementing paste or binder of the coal

are partly hardened, and a reduction of the mass takes place.
As the change continues, there is a progressive devolatilizageodynamic processes, and while the exact changes
and compounds evolved are not known, we do know that there
tion due to
a reduction of the volatile combustible matter.

been commonly assumed that to produce the higher grades
such as anthracite, strong folding was necessary, in order to develop
is
It has
heat and pressure for this degree of metamorphism. M.

R. Campbell (2, 10) has, however, argued with apparent reason that
while the chemical changes involved are induced by heat (of ordinary temperature), still these changes are retarded or prevented
sufficient
the structural conditions (presence of joints, etc.) are

favorable for the escape of the gaseous products of this change.
Thus, for example, the Pennsylvania anthracites are formed not
unless
so much because of heat and pressure, but because of the cracking of

the rocks which allowed thorough oxidation. The same amount
of folding in the Pocono rocks of Maryland has not produced any
anthracite, as the structural conditions were not favorable for the
free escape of the gases.
ECONOMIC, GEOLOGY
16
Cases are known, where the heat causing the changes
and
local, as in
the Cerrillos coal
field of
Crested Butte district of Colorado
(5o),
New
Mexico
is
intense
(80), or
the
where bituminous coal has
been locally changed to anthracite by a near-by igneous intrusion.

Some geologists, notably J. J. Stevenson, have argued that the
anthracite coal has not been developed from bituminous coal by
metamorphism, but that the volatile constituents were partly
removed by longer exposure of the vegetable matter to oxidation
before burial (11). Among paleobotanists there is also a difference
of opinion as to whether the succession, peat, lignite, etc., is a
strictly lineal one.
David White (12) has recently again called attention to the

thrust-pressure hypothesis, which postulates that the devolatilization of coal is the result of thrust pressure.
He
points out that as a result of regional thrust pressure,

essentially horizontal in direction, the coal has become dense,
lithified, jointed,
further reduced in volume, schistose
and even
crushed, or possibly cemented, while gradually becoming progressively dehydrated, devolatilized, and concentrated both as
to
volume and as
to its combustible matter.
This pressure, acting on and transmitted with diminishing

(progressively compensated) force through the buried and loaded
coal-bearing strata, has converted lignite successively into subbituminous, semibituminous,
even into graphitic coal.
The
degree
of
semianthracite,
anthracite,
devolatilization depends, other
and
things being
on the intensity and the duration of the pressure movement, a long moderate pressure being as effective as a short
equal,
intense one.
In considering the evidence bearing on this hypothesis

White points out that we must remember that: (1) The devolatilization of coal is still going on in many parts of the world,
the rate being almost insensible in some districts, but clearly
perceptible in others, where active gas production is observed
in certain mines.
(2) There is no sharp line of separation between
the different kinds of coal, the intergradation being complete
between peat, lignite and semigraphitic coal. (3) The physical

evidences of thrust pressure, such as jointing, cleavage, folding,
become in general more highly developed

and conspicuous, not only in the coal, but also the enclosing
rocks, as the alteration of the coal proceeds, and hence regions
faulting, crushing, etc.,
COAL
of greater change in the coal
17
show the physical
effects of greater
pressure.
In regions of initially equal stress the metamorphism will,

other things being equal, be greater in districts where no buckling
or overt hrusting of beds has permitted escape from the intensity
of the thrust.
The
following theory of coal formation has recently been advanced by

The death of a plant is marked by the loss of power to form
(4).
oxidized hydrocarbon compounds, consequently chemical reactions are set
Dowling
up in the material of the dead plant. The formation of compounds of oxygen

and carbon is the first evidence of decay. With the escape of these gases
the hydrocarbons left behind become unstable, and loss of marsh gas follows.
If fermentation accompanies decay, new hydrocarbon compounds are formed
by this parasitic form of life and the reduction of oxygen is accomplished
without great loss of hydrogen, which is the element that gives character
to the material, especially when in the coal stage.
When solidified by
superposed load, the fermentation is arrested and pressure and heat cause
the subsequent alteration.
Static pressure favors the combination of oxygen with carbon or hydrogen. Heat causes the combination of carbon with
oxygen or hydrogen. Pressure effects the alteration without loss of carbon,
while heat wastes it.
Chemical Changes.
The chemical changes referred to above
be illustrated by the following chemical equations (19, p. 26):
may
VEGETABLE TISSUE =
(1)
5C H O
6
10
(2)
10
Cellulose
(3)
TCcHuOs
Cellulose
Marsh gaa
Carbon oxides
Cellulose
6C H O
Loss BY DECOMPOSITION
= 6C0 + CO + 3CH +
2 4Carbon dioxide
H O + CaHsA
2
Water
CO + 5CH + 10H
8C0
8CO
COALS
Marsh gas
Water
Lignite
CÔ
Bituminous
+ 4CH + 19H O + C^HÔ
Carbon dioxide
Marsh gas
Water
Semibituminous
These equations are not intended to indicate that there is necesa direct passage from cellulose to semi-bituminous coal,
without the development of intermediate stages; and to bring out
sarily
show the changes by a graphical

method we may use the following diagram (Fig. 1) prepared by the
this lineal succession as well as to
late Professor
Newberry.
In this diagram the rectangle A BCD represents a given volume
of fresh vegetable matter, which contains a small percentage of
mineral matter, the rest being organic substances consisting roughly
of 50 per cent carbon (EFCD) and 50 per cent hydrogen, oxygen,
and nitrogen (ABEF). In the change from fresh vegetable tissue
to peat, part of these four elements pass off as gaseous compounds,
ECONOMIC GEOLOGY
18
volume of peat is less ( BGD H) than the origivolume of vegetable matter (A BCD). Since, however, H, 0,
and N have passed off in larger amounts than the carbon, the perbe higher than it was in the
centage of the latter in the peat will
fresh plant tissue.
(Compare BFGI and FIDH with ABEF and
so that the remaining
nal
The
EFCD.}
actual weight of mineral matter will be the same,
VEGETABLE TISSUE
FIG.
1.
PEAT
LIGNITE
BITUM. COAL
Diagram showing changes occurring

graphite.
ANTHRACITE
GRAPHITE
in passage of vegetable tissue to
(After Newberry.)
This change, continued, will

its percentage will be larger.
result finally in anthracite, the last of the coal series, in which the
N) is high and that of the other organic
per cent of carbon
but
(LKM
elements low (J KL}. The amount of compression that occurs in

such changes as those illustrated in the diagram may be understood
when
it is
stated that
are required to
it is
make one
estimated that from 16 to 30 feet of peat
foot of true coal.
The following elementary analyses of peat, lignite, and various

grades of coal clearly illustrate this gradual concentration of carbon
by losses of volatile elements.
ELEMENTARY ANALYSES OF COALS
KIND
COAL
19
Perhaps the first important attempt at classification was

This was as follows:
Jr., based on the fuel ratio (17).
that
of
P. Frazer,
FUEL RATIO
...........
..........
.........
Bituminous ...........
Anthracite
Semianthracite
Semibituminous
100-12
12- 8
8-5
5-0
Objections which have been urged against this are that all coals with a
than 5 are grouped into one class and no provision made
fuel ratio of less
It also groups good and poor bituminous coals together.

for lignite.
Collier (15) proposed that all coals having a moisture content of over
10 per cent should be classed as lignite and those with less as bituminous,
but this differentiation has been shown to be unreliable.

M. R. Campbell, while agreeing to the usefulness of the fuel ratio classification for coals above the bituminous grade, criticised its application to
coals of this type or lower ones, and suggested a provisional classification
based on the carbon-hydrogen ratio (14). 1
GROUP
.........
........
Cj
D
E Semibituminous .......
A
B
<x>
(Graphite)
?-30
Anthracite
G
H
(?)
17-14.4
Bituminous
14.4-12.5
I
J Lignite
12.5-11.2
11.2-9.3
KPeat
9.3-?
LWood
7.2
This table
(?)
26 (?)-23
23 (?)-20
20-17
Semianthracite
is
likewise faulty, as
peats, lignites, subbituminous,

Parr (19), in attempting to
it
does not completely separate the
and even some of the bituminous coals.

make a satisfactory classification, points out
that the term volatile combustible is incorrect as it consists of combustible

Thus in a Pocahontas
hydrocarbons and noncombustible H, O, and N.
coal with 18.70 per cent volatile combustible, 14.5 per cent is hydrocarbons
and 4.2 per cent hydrogen, oxygen, and nitrogen. Again, a North Dakota
lignite
had 41.91 per cent
made up
volatile combustibles,
of 20.28 per cent
hydrocarbons and 21.63 per cent hydrogen, oxygen, and nitrogen. In a

logical classification, therefore, allowance should be made for this inert
volatile matter.
In Parr's classification the terms used are:

ciated with hydrogen, obtained
1
from C
Campbell found that subdivisions based on

value were all unsatisfactory.
calorific
or volatile carbon unassocarbon minus fixed carbon);
vc,
fc (total
total carbon, total hydrogen,
and
ECONOMIC GEOLOGY
20
determined by analysis; and inert volatile matter, obby subtracting from 100 per cent the sum of total carbon, available
hydrogen, sulphur, ash, and water.
It will be seen that Parr's classification, which follows, requires data from
both the elementary and the proximate analysis of the coal.
C, or total carbon as
tained
PARR'S CLASSIFICATION.
Anthracites Proper
Ratio
below 4 %.
Anthracitic
Semianthracite
Ratio
~ between 4 %
Semibituminous
Ratio
^ from 10 %
to 15
%.
Ratio
^ from 20 %
to 32
%.
and 8 %.
Inert volatile from 5
Ratio
~ from 20 %
% to 10 %.
27 %.
to
from 10
Inert volatile
% to 16 %.
Bituminous Proper
Ratio
~ from 32 %
to
Ratio
^ from 27 %
Bituminous
Ratio
from 27
Black Lignites
Ratio
Lignites
~ from 27 %
Inert volatile
Grout expresses the
% to 16%.
16% to 20 %.
up.
from 20
44 %.
% up.
Inert volatile from
Brown
% to 10 %.
to
44 %.
% to 30 %.
fuel ratio as follows (18):
Fixed carbon
100
He makes
Fixed carbon'
the following classification based on

pure coal:
Graphite
Anthracite
Fixed carbon, over 99 per cent.

Fixed carbon, over 93 per cent.
That part of hydrogen content, excluding the hydrogen united with

oxygen to form
water, which is free to enter into combustion with oxygen for the production of heat.
1
COAL
21
Fixed carbon, 83 per cent to 93 per cent.

Semianthracite-
Semibi luminous
Bituminous
Total carbon, 82 per cent to 88 per cent,
I
{ Total carbon, 76.2 per cent to 82 per cent.
|
{ 1'otal carbon, 76.2 per cent to 88 per cent.
|
\ Total carbon, 73.6 per cent to 76.2 per cent.
I
Total carbon, 65 per cent to 73.6 per cent.
[
Fixed carbon, below 55 per cent.
I
{ Total carbon, below 65 per cent.
H' h erade
,
j.
TM
i,
Bro n
lienite
Peat and turf
Wood
f^
D. B. Dowling
(16) notes that
one objection to Campbell's ^=

Jti
classifica-
the necessity for having an elementary analysis, which is rarely

and time requiring. As a substitute for Campbell's classifi"
split volatile
cation, he substitutes what he has provisionally termed the
"
Fixed carbon + \ volatile combustible
ratio
viz
Moisture + \ volatile combustible
tion
is
made,
costly,
An
arrangement of a
series of coals
by
this
method and
also Campbell's
r\
-j-
ratio does not indicate great disagreement; moreover, Bowling's classifica-
tion has the advantage of being based
makes the following subdivisions:

GROUP
on the proximate composition. He
ECONOMIC GEOLOGY
22
White (20) has shown that if a series of coals of

White's Classification.
different ages, kinds, and regions are plotted according to the C (O + ash)
ratios and calorific values as components, they describe a curve, which
shows a close relation between the increase of the above mentioned ratio
:
and the
calorific
power.
fixed carbon in pure coal,

are the greatest variants.
Weathered coals, those having over 78 per cent

and the boghead-cannel group (high in hydrogen)
Oxygen is ranked with ash in this ratio because
the two are approximately equal in anti-calorific potency. This ratio cannot be used as a basis for separation into kinds, such as peat, lignite, etc.
The
Outcrops (24, 25).
usually easily recognizable on account of its
color and coaly character; but unless the exposure is a rather fresh
one, the material is disintegrated and mellowed, the wash from it
Structural
Features of Coal Beds.
outcrop of a coal
bed
is
soil, and if the outcropping bed is on a hillside,

some feet down the slope. This weathered outcrop
has been termed the "smut" or "blossom" by coal miners. In
areas where the beds have been tilted and the
mingling with the

often extending
Coal
Fire Clay
slopes are steep, the outcrops of coal can usually

be easily traced; but in regions where the dip is low
and the surface

attended with
country
is
level,
Coal
Fire Clay
Coal
which
covered with glacial
boring or pitting
Coal
the search for coal
difficulty,
The number
is
is
drift.
commonly
is
increased
often
if
the
In such cases
resorted to.
found in any given

Thus in
region varies, and may at times be large.
the Pennsylvania section, as many as 20 beds are
known; in Alabama, at least, 55 have been counted,
but not all are workable; while in Indiana there are
The
25, of which 9 are minable over large areas.
beds are rarely parallel, and, moreover, thin out if
of coal beds
followed any distance.

Associated Rocks.
Most
coal beds are inter-
bedded with
shales, clays, or sandstones, though

conglomerates or limestones are at times also found
FIG.
2.
Section
in coal measures
Pennsyivama, showof western
under coal beds^

(After Hopkins.)
in close proximity, the latter sometimes even when

of marine character, resting directly on them.
Coal beds are often underlain by a bed of clay,
i
,
u
^
wmch
some regions is off refractory
character
but the widespread belief that all these

unwarranted,
Variations
in
Thickness.
Coal beds
or
"seams " are rarely of uniform thickness over
(Fig. 2);
under
c l a ys are fire-clays is
COAL
large areas;
work in one
23
indeed, a bed which is of sufficient thickness to

mine may be so thin in a neighboring one as to be
This irregularity is in some cases due to

scarcely noticeable.
in
thickness of vegetable accumulations, in other cases
variations
to local squeezing of the coal bed subsequent to its formation.
FIG. 3.
Section showing irregularities in coal seam, a, split;

c, pinch; d, swell; e, cut out.
b,
parting of shale;
These thinnings and thickenings are commonly called "pinchings"

and "swellings" (Fig. 3). In regions of pronounced folding, the
beds are usually found in separate synclinal basins, the intervening
anticlinal folds having been worn away.
While coal beds may vary in thickness from a mere film,
to even more than 100 feet in extreme cases, they are rarely
over 8 or 10 feet thick.
The Mammoth seam
of
the Pennsylvania anthracite

region is 50 to 60 feet thick.
The
Commentry
basin
of
France contains a
bed
of Permian coal
single
that locally exceeds 80 feet
in thickness.
But on one
central
side
of
the basin the coal

FIG. 4.
seam.
up into six beds sep(After Keyes, la. Geol. Sura., II.)
arated by sand and shales.
This indicates that coal accumulation went on continuously on
splits
Section of faulted coal
one side of the basin, but was interrupted

deposits on the other side.
Other Irregularities.
many coal seams.
Splitting (Fig. 3)
is
six.
times by sand
common
feature
The Mammoth
bed, so prominent in most

of the anthracite basins of Pennsylvania, splits into three separate
of
beds in the Wilkesbarre basin. This splitting is caused by the

appearance of beds of shale (called "slate" by coal miners),
which often become so thick as to
split
up the
coal
seam into
ECONOMIC GEOLOGY
24
two or more beds. When narrow, such a bed of slate is called

a parting. The Pittsburg seam of western Pennsylvania shows
"
a fire-clay parting or " horseback
many
from 6 to 10 inches over
square miles.
An
interesting case of parting is found in the 13-foot seam at Inverness,

Scotia.
At the outcrop this showed three shale partings, of 1 foot,
9 inches and 11 inches respectively. At 2500 feet down the dip, these
Nova
A 7-foot seam,
partings had increased to 19, 3, and 22 feet respectively.
lying 284 feet below the 13-foot one, maintained its thickness, however,
for this same distance on the dip.
split
may
occasionally be caused
by overthrust
folds as
shown
in Fig. 5.
FIG.
Section of coal bed, showing the development of a

split," due to an
overthrust roll.
(Pa. Top. and Geol. Surv., Rep. 10.)
"
5.
"
"
which run parallel with

the bedding, others are often encountered which cut across the beds
from top to bottom. These in some cases represent erosion channels
formed in the coal during or subsequent to its formation, and later
filled by the deposition of sand or clay.
In other cases they are due
to the filling of fissures formed during the folding of the strata.
In addition to these
slate
partings,
Coal beds
islands of
may pass into shale, the latter representing possibly

mud or ridges which arose above the level of the marsh in
which the coal plants accumulated.

Faulting (Fig. 4) is not an uncommon feature of coal beds,
and the coal is sometimes badly crushed on either side of the line of
fracture.
The amount of throw and the number and kinds of faults
may vary, so that one might expect normal, reverse, overthrust,
and even step faults.
BITUMINOUS AND ANTHRACITE COAL
A
Areas
containing workable
coal beds
Indicates anthracite coal
Areas that
may
contain workable
coal beds
coking coal
Areas probably containing

workable coal beds under
such heavy cover as not
Areas
oontatnlng workcA
coal beds
to be available at present
PLATE
IV.
Map of
coal fields of
ti
Qrxnwich
Areas that
may

workable ooal bedt under
each heavy cover at not
contain workable
coal bedt
to be available at present
ii
-d
States.
(U
S. Geol.
Survey.)
Areat
containing workable
lignite bedt
Areas that
may
contain workable
lignite
bedt
COAL
Parr and" Hamilton
Coals.
of
Weathering
25
(27),
as a result of their
investigations of the weathering of coal, concluded that
submerged coal
does not lose appreciably in heat value, but that outdoor exposure results
in a loss of heating value varying from 2 to 10 per cent.
Dry storage is
only of advantage for high sulphur coals, where the disintegrating effect
of sulphur in process of oxidation facilitates escape of hydrocarbons by
oxidation of the same.
end of
five
Storage losses usually appear to be complete at
months.
Coal Fields of the United States. 1
Coal in com(PL IV.)

mercial quantities occurs in thirty-three states and territories, as
These occurrences can be grouped into the
well as in Alaska.
following fields:
AREA,
Appalachian,
including
parts
of
Pennsylvania, Ohio,
Maryland, Virginia, West Virginia, Eastern Kentucky,
Tennessee, Georgia, and Alabama
(2) Atlantic Coast Triassic, including parts of Virginia and
North Carolina
())
SQ. MI.
69,755
210
(3)
Eastern Interior, including parts of Indiana,
(4)
11,000
(5)
Northern Interior, including a part of Michigan

Western Interior, including parts of Iowa, Missouri, Nebraska, Kansas, Oklahoma, Arkansas, and Texas
Gulf Coast Lignite Field, including portions of Arkansas
74,900
(6)
(7)
and Texas
Rocky Mountain
Illinois,
and Western Kentucky
47,000
.
zona,
New
2,100
field,
including parts of Colorado, Ari-
Mexico, Utah, Wyoming, Idaho, Montana,
North Dakota, South Dakota

Coast Field, including parts of Washington, Oregon, and California
126,022
(8) Pacific
1,900
332,887
(9)
Alaska
1,210
The estimates of areas given above are from calculations made by the
United States Geological Survey, and are to be regarded as fairly accurate,
but some of these fields may be extended in the future by the development
This applies especially to those in
of areas now classed as unproductive.
which the coal lies too deep to be profitably mined at present. It is a
noteworthy fact that the production of the fields is by no means proportional to their areas (compare above list with table, p. 54).
Proximity
to markets, value of the coal for fuel, and relative quantity of coal per
square mile of productive area are factors of importance in determining
the output of a
1
is
The Rhode
field.
Island area of graphitic anthracite, formerly included in this
referred to under Graphite.
list,
26
ECONOMIC GEOLOGY
ECONOMIC GEOLOGY
28
The
Geologic Distribution of Coals in the United States.
table, which shows both the geologic and geo-
accompanying
graphic distribution of coals in the United States, indicates that

the Carboniferous coals are found chiefly in the eastern half
of the country, and the younger coals in the western half.
The
separation of the Carboniferous coals into well-defined areas is
1
probably the result of folding and erosion, and to a certain
extent, the
The
latter
same is true of the Rocky Mountain Coal fields.

have often been seriously disturbed by post-Creta-
ceous uplifts.
Appalachian
Field
(33,
36,
39,
91,
99,
101, 109, etc.).
This,
the most important coal field in the United States, extends 850
It shows
miles, from northeastern Pennsylvania to Alabama.
a maximum of 180 miles at the northern end, narrows to less than

30 miles in Tennessee, and expands again to 85 miles in Alabama.
About 75 per cent of its area contains workable coal. At the
southern end the coal measures pass beneath the coastal plain
deposits, and they may connect with the Arkansas Coal Measures
beneath the Mississippi embayment.
Being closely associated with the Appalachian Mountain
uplift, the coal measures of this region partake of the structural
features of the Appalachian belt.
The eastern margin of the field
borders on a belt of steeply folded strata, forming the Appalachian
Valley, and hence the coal-bearing formations are much folded
here (Fig.
while at the southern end of the
field they are

Extensive erosion following the
folding of the Coal Measures has resulted in the development of
a number of basins.
The Coal Measures of the Appalachian field consist of a great
6,
10),
faulted in addition
thickness
of
(Fig.
overlapping
limestone, shale,
fire clay,
6).
lenses
and
of
coal.
conglomerate,
sandstone,
The formations
in general
show a thinning from the eastern margin of the field, westward,

as well as showing a decrease in the number and thickness of the
beds.
Owing to the lenticular character of the deposits, and the
local thickenings, it is difficult to trace individual
beds of coal
over wide areas, or correlate sections at widely separated points.

The middle Carboniferous or Pennsylvania!! includes most
of the coal beds of the Appalachian field, but there are some
upper Carboniferous and in the Pocono of the lower

Carboniferous or Mississippian.
also in the
Ashley, Econ. Geol., II: 650, 1907.
COAL
The
classic section of the
in Pennsylvania,
(1)
(2)
was
29
Coal Measures,
first
worked out
as follows:
Dunkard or Upper Barren Measures.

Monongahela or Upper Productive
Measures.
Conemaugh] or Lower Barren Meas-
(3)
ures.
or
(4) Alleghany
Measures.
(5)
Lower
Productive
Pottsville conglomerate.
At the time it was made the second and

fourth members were thought to be the
only ones carrying coal, and hence the name
"Productive"; but since then the Pottsville
-5
has been found to be locally productive,
and a few seams have been found even in

the Barren Measures. By some the Dunkard
series is
The
now
placed in the Permian.

named above are recogniz-
divisions
able also in Ohio, West Virginia, and Maryland, but farther south the identification of
all
becomes
difficult.
The Appalachian
field
is
two parts of very unequal

anthracite
field
of
divisible into
size, viz. (1)
the
northeastern Pennsyl-
vania; and (2) the bituminous area, which

1
occupies the balance of the field.
Pennsylvania Anthracite Field (100).

This field (Fig. 7) lies in the northeastern
part of the state, covering an area of about
3300 square miles, about one-seventh of
which
is
ures.
The
by workable coal meashas four main subdivisions,
underlain
field
known
respectively as the northern, eastern

middle, southern, and western middle. Intense folding (Fig. 8) has placed some of
the coal in synclinal troughs, where it has

been preserved from erosion which [has removed the coal from
the intervening anticlines. Therefore the anthracite is found in
a number of more or
1
less
separated narrow basins.
This includes some small areas of semianthracite.
It
has been
ECONOMIC GEOLOGY
30
estimated that from 94 to 98 per

cent of the coal originally deposited has been
removed from
by denudation.
this field
The Coal Measures
of the an-
thracite district consist of beds
of sandstone,
shale,
and
clay,
with coal beds at intervals varying from a few feet to several
hundred
feet, though rarely ex200

feet.
The coal beds,
ceeding
which vary in thickness from a
few inches to 50 or 60 feet, occur
throughout the entire section of

the Coal Measures, but are most
important in the lower 300 to 500
feet.
Map of Pennsylvania anthra-
FIG. 7.
cite
field.
Sure.,
The
(After Stock, U. S. Geol.

Rept., III.)
22dAnn.
is
Among these theMammoth

importance, but splits in
of
some
areas.
anthracite section, though not yet accurately correlated with the

field of Western Pennsylvania, is nevertheless known to con-
bituminous
ga<m(C)cro
FIG.
8.
the Binthei
Sections in Pennsylvania anthracite

Surv.,
Cik Bwrn
field.
(After Stoek, U. S. Geol.
22d Ann. Rept., III.)
tain the Pocono, Mauch Chunk, Pottsville, and Alleghany series, as well as
some of the higher ones of the Coal Measures (39)
The Pottsville conglom.
COAL
31
erate forms an important stratigraphic horizon, recognizable

logical characters and bold outcrops.
by
its litho-
The position of the coal beds and physical characteristics of the coal have
necessitated the use of special methods of mining and of treatment after
mining (100). Sharpness of folding and steep dips prevail, these introducing many mining problems not found in bituminous regions. When
brought to the surface, the anthracite consists of lumps varying in size and
mixed with more or less shaly coal called bone, so that before shipment
This is done in a coal
to market it is necessary to break, size, and sort it.
breaker (Fig. 9), in which the coal is crushed in rolls and sized by screens,
while the slate is separated either by hand, automatic pickers, or jigs.
These breakers are a prominent feature of the anthracite region, and much
money has been spent in increasing their efficiency. As the result of years
of mining, the refuse from the breakers, consisting of a fine coal-dust and
"
culm," has accumulated in enormous piles. Much of it is
bone, termed
now being washed to save the finer particles of clean coal and much is also
washed into the mines to support the roof, so that the pillars of coal, originally left for that purpose, can be extracted.
;
account of its cleanliness and high fuel ratio, anthracite coal is

Most of that mined is marketed in the
for domestic purposes.
eastern and middle states, although small quantities are shipped to the
western states, especially those that can be reached by way of the Great
On
much prized
Lakes.
FIG. 9.
Coal breaker in Pennsylvania anthracite region.
The
Bituminous Area (36, 41). Pennsylvania.
about
of
area
an
includes
12,000
field
Pennsylvania bituminous
of the state (PL V),
square miles lying mostly in the western part
In the northboundary.
an
and having
exceedingly irregular
form outliers,
measures
coal
the
is
where
western
slight,
folding
Appalachian
part,
capping the high
marked
synclinal
and ridges; but to the eastward, the more

structure has resulted in the formation of a
hills
ECONOMIC GEOLOGY
32
strung out series of basins. The most northeastern areas are quite
and include the Bernice (semi-anthracite), Barclay, and
isolated,
Blossburg basins, as well as an easterly one, the Broadtop (PI. V)

The coals range in age from Pottsville to Dunkard, and in about
four-fifths of the territory the thickness of the Upper Carboniferous
rocks, including
Dunkard,
is less
than 1000
feet,
while in one-third
Faults are rarely found. On account of the

variation in thickness of the sandstones and other rocks, splitting
it is
under 500 feet
and other
of coal seams,
in a general
(41)
irregularities, correlation is difficult.
But
the beds above the Pittsburg seam appear to be

more regular in their appearance and more constant in their distance from one another, than the beds in the lower part of the section.
The number
way
of coal
seams recognized in the several
series is as
follows (99):-
Dunkard
series,
Monongahela,
Conemaugh,
Alleghany,
1100-1200
200- 300
500- 700
300
12 coals
6 coals
feet thick,
6 coals, mostly unimportant
feet thick,
feet thick,
feet thick,
4 coals
several
Pottsville,
The Alleghany
about forty per cent of the bituminous coals

While most of the coal beds are of limited extent,
the celebrated Pittsburg seam at the base of the Monongahela has an average thickness of 7 feet over about 2100 square miles of its area and an estimated tonnage of 9,641,792,907 short tons, thus making it one of the most
important bituminous coal beds in the world. This same seam is also
recognizable and important in Ohio, West Virginia, and Maryland.
Ohio.
In Ohio (40, 90-92) the five subdivisions of the middle and
Upper Carboniferous are also recognized, and there are at least 16 coal beds,
of which 6 are important.
These include the Pomeroy, 1 Pittsburg, Meigs
(Sewickley of Pennsylvania), Clarion, Lower Kittanning, Middle KittanThe Pittsburg
ning, Upper Freeport, Wellston, and Block (Sharon).
coal is of high importance and the Middle Kittanning includes the well-
mined
yields
in Pennsylvania.
known Hocking Valley
coal.
lie in three broad northeast-southmeasures of these being separated by Mississippian or Devonian Rocks, exposed by erosion of the intervening anticlines.
The eastern or Potomac basin is the most important of the three.
The geologic position and number of coals is as follows: Monongahela,
with Pittsburg (Elk Garden), Tyson, and Koontz coals; Conemaugh, 2
coals; Alleghany with Upper Freeport (Thomas or three foot), Middle
Maryland.
west synclinal
In Maryland the coals
folds, the coal
Kittanning (Davis or six foot), Brookville (Parker), and Clarion (BlueThe coals are good steaming fuels
baugh); Pottsville, with two seams.
and
will coke (71).
Formerly regarded as Pittsburg, but shown hy Bownocker to be equivalent of

Redstone of Pennsylvania and West Virginia.
(Ohio Geol. Surv., 4th ser., Bull.
1
9, p. 96,
1908
PLATE VI.
FIG.
1.
Pit working (strippings) near Milnesville, Pa.
uncovered in bottom of
FIG. 2.
View
in
Arkansas coal
field.
The Mammoth seam
pit.
(H. Riea, photo.)

(33)
is
ECONOMIC GEOLOGY
In this state the Coal Measures
West Virginia.
occupy an irregular rectangle extending from the Alleghany
Mountain region northwestward to the Ohio River. The
deepest part of the Appalachian basin takes a southwest
course across the state, the axis rising to the southward.
From this the strata rise to the northwest, while to the
southeast the basin shows a series of folds of increasing
steepness and height towards the eastern boundary of
the fields.
The
in
Pocono to the Dunkard

The Pocono contains some unimportant beds of
coal beds range from the
age.
anthracite along the
-3
~2
border of the field, but

noted for its petroleum and
eastern
westward the formation
is
absence of coal.
The
Pottsville carries the coals of the
New
River and
these underlying an area of about 2600

square miles in the southeastern and eastern part of the
field. These coals are of high quality, being low in sulphur
Pocahontas
series,
In northern West Virginia the Alleghany series

but with one exception these
disappear to the southwestward. The Conemaugh carries
two coal beds of importance, while the Monongahela carries
and
ash.
carries several coal beds,
six distinct beds, including
No
J3
O
,_J"
coals of
the famous Pittsburg seam.

are found in the Dunkard.
much importance
The coals of the Mountain Province

Virginia (111).
are of either Mississippian or Pennsylvanian age.
The
first
or least important forms a belt of small areas of

semibituminous or semianthracite character ex-
either
Wythe to Frederick counties, but the only

much importance is the Montgomery-Pulaski
tending from
one
&
of
counties area.
2
1
o a
The Pennsylvanian
coals
lie
in the
extreme southwestern
*2
part of the state in the Cumberland Plateau region, and

The two chief fields
are the most important producers.
are the Pocahontas or Flat Top and the Big Stone Gap
coal fields.
The
_G
Pottsville
coal
which are probably mostly of

show comparatively little disturbance,
measures,
age,
although they lie immediately west of the highly folded

rocks of the Great Valley (Fig. 10), but the Pocahontas
field is abruptly terminated on the east by a fault.
In
the Pocahontas
field
there are at least six workable beds;
steaming purposes, shows

often a remarkably low ash content, and makes a good
coke.
The Big Stone Gap field, which extends into Kenthe coal
is
of excellent quality for
tucky, contains eight workable seams and

important producer of coal and coke.
is
even a more
Southern Appalachian Field.

In the southern
Appalachian field the coal-bearing rocks are mainly
COAL
of Pottsville age,
35
and in the Birmingham, Ala.,
district,
have a thick-
ness of probably 5000 to 6000 feet.

The Coal Measures, which
show much disturbance on their eastern margin, with but little
toward the west, are
divisible into a
lower (Lee,
Lookout, or
Millstone Grit) group, carrying about three thin seams in the

lower part, and an upper group, with many beds of coal.
Although the coals and associated rocks were originally deposited

in a broad trough, this has been subsequently folded, and faulted,
while the basins are separated partly by faulting and partly by
erosion of intervening anticlinal crests.
There are three main districts, known as the Jellico, Chattanooga,
and Birmingham, the latter containing four fields, viz., the Warrior,
Coosa, Cahaba, and Blount Mountain.
The
Triassic Field (111, 112).
This coal
field,
which
is
more important
economically, having been worked as early as 1700,

includes several small steep-sided basins (Fig. 11), lying in the Piedmont
than
historically
Cornwtllis
FIG. 11.
HiH
General structure section of the Richmond Basin in the vicinity of

A, A, A, minor flexures, with beds down thrown to the west;
James River.
The heavy black band represents the supposed position of the

North and south of this section the beds appear to be deeply faulted
down against the western margin, and the apparent synclinal structure disThe superficial portion of this section is based on observation and
appears.
(After Shaler and
reliable information; the deeper portion is hypothetical.
Woodworth, U. S. Geol. Surv., 19th Ann. Rept., Pt. II.)
/, /, /, faults.
coal beds.
It is probable that the coalregion of Virginia and North Carolina.

were formerly
bearing beds of the several areas, originally horizontal,
and denudation.
continuous, having been separated by folding, faulting,
In addition to this, the coal is cut by dikes and sheets of igneous rock,
altered it to natural coke or carbonite.
which have
locally
Eastern Interior Field
(34,
57-59,
65-69).
This
field is
an
oval,
northeast and southwest,

elongated basin (Fig. 12), extending
the lowest portion,
toward
with the marginal beds dipping gently
It
horizontal.
are
beds
the
nearly
which lies in Illinois, where
of
small
a
and
part
Indiana,
southwestern
covers most of Illinois,
with some small outliers in Missouri, near St.
Western Kentucky,
Louis and St. Charles, and two
in Illinois.
ECONOMIC GEOLOGY
36
The
coal-bearing rocks rest unconformably on lower Carboniferous, Devonian, and Silurian strata, the basal
u
'""A"
member
being a sandstone, probably the equiv-
alent of the Pottsville.
which have a
The
maximum
coal-bearing rocks,
thickness of fully 2200
^ feet in Illinois, belong to the Coal Measures,

"J.
although the upper part may be of Permian
age, and the highest workable coals beds are
classed as Freeport or Conemaugh.
The coal
gj
r
seams occur in the lower portion of the section,

and hence outcrop around the margin, the
mining operations being therefore confined to
^ a narrow
"3
belt,
because near the center of the
basin the coal beds underlie too great a thickness of unproductive strata to permit of prof-
working under present conditions.

Great difficulty has been encountered in attempts at correlation of the coal beds of different
parts of the field, because of the varying section
itable
<
shown from place to
place,
and lack of continuity
In consequence, the custom has

arisen of giving the coal beds numbers instead
of the beds.
of
names.
The
coals
of
the Eastern
Interior
field,
although varying widely in quality, are all

On account of their higher perbituminous.
centage of ash and sulphur, they are little used
Most of the coal used in and near
for coking.
is supplied from it; but even within

the Appalachian coals enter into comThe cannel coal found near Cannelspetition.
this field
the
field
burg, Kentucky, which
producer found in this

market.
is
the only good gas

finds a ready
field,
COAL
37
beds are not coincident, but as a general rule the coals above
No. 2 in
the western part of the state are persistent in extent and
thickness over
large areas, while in the eastern portion all the seams are
irregular in
both extent and thickness. As a rule, the lower seams are better
than
the upper ones, and the quality also increases from north to
south.
The
Illinois seams vary from 3 to 8 feet in
thickness, and all are bituminous.
Ashley subdivides the Indiana section as follows:
Permian-Merom group; Upper or Barren Measures, O'-iOO'.
Wabash group; main coal-bearing measures, 100'-60(X.

Mansfield group; basal sandstone member, 0'-200'.
The coal field is roughly divisible into two areas, viz. an eastern
or
"block-coal" area, and a western or bituminous area.
The former is
also bituminous, but shows a peculiar block-like
jointing.
The Indiana section
shows at least 25 distinct coal beds (59),
nearly all of them 2 feet
Coal Measures
i.
or
more thick
in
some
places, and nine of them

continuing of minable
over
thickness
large
The upper five

of the nine numbered
ones are coking and
areas.
occur in broad sheets, FIG. 13.

Shaft house and tipple, bituminous coal mine,
while the lower four
Spring Valley, 111.
occur in basins and are
not extensively workable. No. 5 is the most important bed in the state
and can be correlated the entire length of the field.
In Kentucky the coals have been numbered from 1-12, beginning at the
bottom and lettered beginning at the top. Nos. 9, 11, and 12 are the
chief ones worked.
One of these is exceedingly persistent, being found
under a part of the whole of two counties, with an average thickness of
5 feet, and at a depth commonly of less than 200 feet.
Northern Interior Field (72).

This field forms a large basin in
which the coal dips irregularly from the margin toward the center
(Fig. 14) but on account of the heavy mantle of glacial drift it has
been difficult to determine its exact boundaries, and prospecting is
The Coal Measures, which
necessarily done by means of drilling.
are probably of Pottsville age, attain a total thickness of 600 to 700
feet in the center of the basin, and include 7 horizons of workable
coal with an average thickness of 2 feet and rarely exceeding 4 feet.
The Verne coals near the top may correspond with the Mercer coals
,
Ohio (Lane). Coal is found near the center of the basin at

depths of 400 feet or more, though the beds that are mined are
mostly at depths of 100 to 250 feet. All the coals are bituminous
of
ECONOMIC GEOLOGY
38
and used
chiefly for fuel,
but some are coking, and others
ably prove of value for gas manufacture.

are important mining towns.
will
prob-
Saginaw and Bay City
These
Western Interior Field and Southwestern Fields (35).
two fields form a practically continuous belt of coal-bearing forma-
FIG. 14.
tions,
Generalized section of Northern Interior coal field.

U. S. Geol. Surv., 22d Ann. Rept., III.)
(After Lane,
extending from northern Iowa southwestward for a distance

Throughout most of this area the
of 880 miles into central Texas.
lie horizontal, or have a gentle westward dip averaging 10 to

20 feet per mile, but a notable exception is found in the beds of eastern Oklahoma and Arkansas, which are rather strongly folded,
reminding one of the Pennsylvania anthracite area.
beds
FIG. 15.
Composite section showing structure
of
lower coal measures of Iowa.
(After Keyes, la. Geol. Surv., /.)
Western Interior Field.
The Coal Measures, composed

and
of lime-
unconformably on the
and
under
beds
of Permian, CretaMississippian
dip westwardly
and
Pleistocene.
the beds increase
Toward
the
south
and
west
ceous,
in thickness, the maximum being 1000 feet in Iowa (62), 3000 in
Kansas (63), and 200 in Missouri (74). In a general way there is
a prevailing dip westward of 10-20 feet per mile; in detail the dip
stones,
shales, fire clays,
coal beds, rest
Wakartisa River
Sugar
.'irj
,',',';'
Work
De Soto
792
V.'ilder
772
Holiday
W6lM
Mia Lecoroptoa
\\
Argentine
750
ECONOMIC GEOLOGY
40
south-southwest in Iowa, west-northwest in Missouri, and usually

northwest in Kansas.
is
The Coal Measures are divisible into two parts. The lower is
known as the Des Moines in Iowa, and the Cherokee and Marmaton
The upper is termed the Missourian in Iowa, but in
in Kansas.
Kansas is made up of the Pottawatomie, Douglas, and Shawnee.
In both states most of the coal mined comes from the Cherokee shales
Those found in the upper measures are thin, even though
horizon.
persistent.
Most of the coal
mined in this field comes from the lower part of

the coal measures, where the beds are irregular in thickness and
in
consedistribution,
quence of deposition on
a very uneven surface.
the
All
field
coals
of
CLASSIFICATION BY
N. F. DRAKE.
CLASSIFICATION
J. A.
BY
Bogey formation.
Upper Witteville coal.
Lower Witteville coal.
this
are essentially bitu-
minous and used chiefly

for steaming and heating
purposes, being of no
Savanna formation.
Cavanal coal.
value for either coking or

gas making. Some of the
seams will coke, but there

is
no demand for the
product, and the sulphur
and ash are too high for
TAFF
DETAILED SECTIOK.
GENERAL SECTION.
Poteau group
Cavanal (Cavaniol)
group.
McAlester coals.
gas making.
McAlester shale.
The Oklahoma and Arkansas
portions
Western Interior
of
the
field
are
directly connected, but

the coals differ somewhat.
The
homa
rocks of the Okla-
field (60),
Lower Coal Measures,
Atoka formation
belong to
the Coal Measures (Fig.

16), the lowest coal beds
being
Hartshorne coals.
Hartshorne sandstone.
probably
in
Columnar section of
Oklahoma coal field.
FIG. 16.
in
Geol. Sure.,
22nd Ann.
coal-bearing rocks
(After Taff, U. S.
Kept., Pt. III.)
the
upper part of the Lower Coal Measures, and the highest coal in
the Upper Coal Measures.
The coal field is characterized by both folds and faults. The
anticlines are generally narrower and deeper than the synclines, with
a tendency to overturn to the north, but the folds die out to the
COAL
41
westward and northwestward. There are seven important beds of

workable character, as well as some that are workable locally.
The coals are bituminous and coking.
In the Arkansas field (49) the rocks (sandstones and shales) are all
of Pennsylvanian age, and involve a section several thousand feet
which can be correlated fairly well with the Oklahoma area.
thick,
Names
of ooal Ixds
ECONOMIC GEOLOGY
42
This area, lying in northern Texas,

(40).
separable into a northern and southern portion by an arm of
Cretaceous strata, extending across it. The coals, which are all
Southwestern Field
is
Pennsylvanian, rest uncomformably on the Mississippian and are

by the Permian on the north. There are five divisions,
overlain
which carry three workable coal beds, and while all are of bituminous character, none of them are coking.
These cover a broad area extendRocky Mountain Fields (38).
ing from the. Canadian boundary southward into New Mexico,
a distance of about 1000 miles, and including a large number of
Most of these beds lie
fields of varying size and irregular shape.
within the mountainous region, but at the northern end of the area,
in Wyoming and the Dakotas, the coal fields extend eastward under
the Great Plains for some distance. The age of the coal ranges
from Lower Cretaceous to Eocene (Tertiary), though most of it
belongs to the former.
While portions of
this
enormous area
of coal-bearing strata are
only slightly disturbed, mountain-building forces and igneous intrusions have affected a large proportion of the region, often materi-
changing the character of the coal. Thus, while in undisturbed portions of the field the beds may be lignitic (PI. VIII.
ally
Fig. 2), in the disturbed parts they
have been altered to bitu-
Igneous intrusions may have changed the latter locally

to anthracite, as in the Crested Butte (55) area of Colorado or the
minous.
Cerrillos field
coals produce
Some of the bituminous

of New Mexico (80).
an excellent quality of coke.
Colorado (54, 55) is the most important coal-producing state of the Rocky
Mountain region, the distribution of its coal fields being sho\vn in Fig. 18.
The Raton field in the southeastern part of the state, extending into New
Mexico (82), is the most important producer and yields coking coal. Like
many of the fields of this region the coals which are of Cretaceous age are
both folded and faulted. They are, moreover, crossed by igneous intrusions,
which have in some places produced natural coke, but in others destroyed
the value of the coal.
The subbituminous coals of the South Platte field,
and the bituminous ones of the Canon City area are also important. AnThe latter
thracite is obtained in the Yampa and Crested Butte fields.
lies at the eastern end of the great Uinta Basin field, which extends into
Utah.
Wyoming (116-118) has a larger percentage of its area underlain by coalbearing rocks than any other Rocky Mountain state, but most of this lies
in the Great Plains region, and the coals, which are chiefly Cretaceous, are
on the whole of subbituminous character (Fig. 19). The Green River
basin in southwestern
Wyoming
is
the most productive area and yields
PLATE VIII
FIG.
1.
View
in sub-bituminous coal area,
between Minera and Cannel, Texas.
(H. Ries, photo.)
FIG.
2.
Lignite seam, Williston, N. Dak.
(After F. Wilder, photo.)
(43)
ECONOMIC GEOLOGY
44
bituminous coal, and the same is also obtained from small areas in the
Powder River basin of northeastern Wyoming.
Utah (109) has two large coal areas (Fig. 18). The largest of these is
that of the Uinta Basin, which carries Upper Cretaceous bituminous coals
of coking character, and which are worked chiefly in the Book Cliffs fields
Areas ith workable

bituminous and
Areas of workable
gubbitumlnous coals
Probable areas of
workable coal
Possible areas of
worko'
le
Probable areas of
Korkable coal, but under
Areas probably
containing subcoal under
heavj cover
FIG. 18.
Map
showing distribution of different kinds of coal
in Colorado.
(After Parker, U. S. Geol. Surv.)
on the southern rim of the basin. The other large field lies in southern
Utah, but is not commercially developed.
Other Rocky Mountain States.
A great area of Eocene lignitic coal is
found in the Fort Union region of North Dakota, South Dakota, and Montana (75-77). Passing towards the mountainous district of Montana, the
coals pass into high-grade subbituminous and bituminous ones.
Red
Lodge, Carbon County, yielding a coal between bituminous and subbitumi-
COAL
45
nous, is the most important producer, and the Bull Mountain area
second.
Coking bituminous coal is also obtained.
Areas with
workable bituminous
and some anthracite
FIG. 19.
Possible areas of
workable
subbitumiuous coali
Map showing distribution of
subbituminous coal
under heavy cover
different kinds of coal in
Parker, U. S. Geol. Sun.,
Gulf Province Lignites
Min.
is
now
Ail-as with
workable
Bubbitumiuous
Wyoming.
(After
Res., 1910.)
These are of Eocene

low grade, with the exception of those
along the Eio Grande, northwest of Laredo, which may be regarded as subbituminous. Those found near Eagle Pass are
of still better quality, but occur in the Cretaceous.
Pacific Coast Fields (37).
Tertiary coals, partly bituminous,
though mainly lignitic, occur scattered over a wide area in the states
(Tertiary) age
and are
of California (50-53),
(70, 73, 105-107).
all
Washington
(114),
and Oregon
(93, 94).
The
separate fields are limited in extent, and widely separated.

Their output is small as compared with some other states, but
becoming of growing importance.

Of the scattered fields in Washington, the most important lie
The total thickness of
directly east of Seattle and Taconia.
still it is
46
ECONOMIC GEOLOGY
coal-bearing strata is about 10,000 feet,
but important coal beds are found
The
only in the lower 2000 feet.
of
the
coal
with
varies
the
extent
quality
dynamic disturbance, and hence
of the
there
may
be variation even in a single
Some
field.
of the coal
is
coking.
The
however, from compe-
industry suffers,
tition with oil fuel.
Both California and Oregon are small

In the former coals of subbituminous character have been mined
near Tesla, Alameda County, and recently coal of good bituminous grade
has been worked in Stone Canyon,
Monterey County. Indeed this is of
producers.
-9
high quality to compete with

foreign coals brought into San Francisco.
sufficiently
In Oregon, the Coos Bay field has

been a small but fairly steady producer.
Oil may be said to dominate the fuel
situation along the Pacific coast, and as
long as this continues, the
demand
for
coal will be limited.
Alaska
Although Alaskan
mined in 1852 at Fort
(45, 46).
was
coal
first
Graham, and
coal
discovered at a
deposits have been

of localities,
number
the quantity produced is small. This

is due to location (Fig. 21), character
of
deposits,
which
are
often
badly
folded and
crushed, cheaper oil fuel,

and also conditions obtaining as relating to patent claims regulated
by the
Government. These last named
obstacles have no
been largely removed and developments are expected
U.
to
S.
follow
which
sible.
will
the
building
render the
of
railroads
fields
acces-
Indeed, in 1913, the domestic

iBur. Mines, Bull. 36, 1912.
COAL
product
formed
only
1.7 per
cent
47
of all
the
coal
used in
Alaska.
The
table
Alaskan
FIG. 21.
on
p.
48 gives the character and location of the
coals.
Map
and coal-bearing rocks, so

(After Martin, U. S. Geol. Sure., Bull. 314.)
of Alaska, showing distribution of coal
far as
known.
Canada.
The coal regions of Canada include: (1) The
Maritime Provinces; (2) Western Provinces; (3) Vancouver
and other Pacific Coast islands.
Maritime Provinces.
Leaving out the coals of New Brunswick, which are of little importance, we have several areas
of active production in Nova Scotia.
There the coal-bearing
rocks range from Lower Carboniferous to possibly Permian,
but the only important beds are those occurring in the CoalMeasures proper, lying above the Millstone Grit. The four
areas are (1) the Cumberland (including Joggins and Spring
In all of these
Hill) (2) Pictou, (3) Inverness, and (4) Sydney.
the coal is bituminous, and in (2) and (4) of coking character.
The beds show more or less folding, and in one area at least
It is interesting to note that in.
(Pictou) some strong faulting.
,
ECONOMIC GEOLOGY
48
KIND AND DISTRIBUTION OF ALASKA COALS

SYSTEM
COAL
49
Saskatchewan.
Lignite-bearing Tertiary rocks cover a wide
extent of territory in the southern part of the province, and a
number of beds are known, which are worked chiefly in the
SCALE OF MILES
FIG. 23.
Map
showing coal areas of Western Canada.

Geol. Surv.,
Mem.
59.)
(After Bowling,
Can-
ECONOMIC GEOLOGY
50
Souris field.
The Cretaceous coals of the Belly
(Fig. 23.)
River series are as yet unimportant.
Alberta.
Coal is found at three horizons of the Cretaceous,
and part of Paskapoo, Belly River and Kootenay.
Edmonton
viz.,
The Edmonton coals lie in a great syncline, with the Paskapoo
sandstone forming the upper beds in the center. The beds
of the eastern limb have a lower dip than those of the western
c
ne towards the mountains, so that the coals change from lignites
coking coals in the foothills. Edmonton is the chief mining center.

The Belly River coal series, which covers about 16,000 square
miles in central and southern Alberta, carries coals ranging
from lignites near Medicine Hat to subbituminous coals around
in the northeastern part to
Lethbridge, but the series traced to the foothills also carries
coking coals.
The
coal of the
Kootenay formation
lies
deeply buried under
the Plains, but in the Rocky Mountains it is exposed at a number of points in uplifted fault blocks, and along the crests of
Some is also found in synclinal troughs. The Alknown both in the outer ranges and in the foot-
anticlines.
berta areas are
from near the international boundaiy to beyond the AthaThe coals are generally bituminous, sometimes of
coking character, but semianthracite and anthracite beds are
also known.
The bituminous type is actively worked in the
Crows Nest Pass district at Coleman and Frank, while the
anthracite is mined in the vicinity of Canmore and Banff.
British Columbia.
Cn the mainland, the coal areas, which
are more or less isolated, are chiefly of Lower Cretaceous age,
and of bituminous character, although sometimes locally altered
hills
basca River.
An
important basin is situated in the western

where the section, sometimes
showing 3700 feet of measures, may carry over 20 beds, exceedto anthracite.
part of the Crows Nest Pass,
Scattered deposits of Tertiary coal

ing 1 foot in thickness.
are also known, and worked specially around Princeton and in
the Nicola Valley. These have been partly covered by igneous
flows,
and
locally altered to
bituminous
coal.
The
Vancouver Island.
coals, so far as known, are of Upper

Cretaceous age, associated with the thick Nanaimo series of
variable degree of folding and some faultclastic sediments.
ing occurs,
and the seams lack
minous coals are coking.
persistence.
Some
of the bitu-
PLATE IX
FIQ.
FIG.
2.
1.
Beds
of
subbituminous coal near Estevan, Sask.
Coke ovens and
tipple at
Coleman, Alberta;
(H. Ries, photo.)
Crows Nest Pass
(H. Ries, photo.)

(51)
field.
ECONOMIC GEOLOGY
52
Yukon.
Lignites of Tertiary, and lignites to anthracites of
Jura-Cretaceous age are known.
Other Foreign Fields.
Europe contains extensive deposits of coal, the
bituminous and anthracite varieties being chiefly of Upper Carboniferous
age, although important Lower Carboniferous deposits are known in Central
Russia and Scotland. Of the Upper Carboniferous or Coal Measures
proper, there are important deposits in western Germany, Belgium, Northern
France, and Great Britain. They are mostly bituminous, and may show
strong folding and faulting. Anthracite is mined in Wales and Russia.
The lower grades of coal chiefly of Tertiary age, are an important source
of supply in southern Russia, as well as in Austria, Germany, and to a
lesser extent France.
Asia contains extensive areas of Permo-Carboniferous coals in China

(anthracite to lignite), as well as India, while Tertiary coals are an important
source of supply in Japan (bituminous) and northeast Siberia.
Australia contains both Carboniferous and Tertiary coals, the former

being especially important in New South Wales. In South America the
best grades of coal appear to be those along the Pacific and Gulf of Mexico
in formations of Tertiary age, while in Africa, the important deposits
of
Carboniferous to Jurassic age
are confined to the southern part of the
continent.
In Mexico the most important
fields are
Cretaceous ones of bituminous
character, near the Texas border, on the Rio

The Philippine coals are of Tertiary age,
Grande and its tributaries.

and range from lignite to bitu-
minous, but the area known to be underlain by mineable coal does not
cover more than 7 square miles.
Much attention has been
Estimated Coal Reserves of the World.
given in recent years to the necessity of conserving the coal supply, and in
on p. 53 and collected by the executive com-
this connection the figures given
mittee of the International Geological Congress of 1913, l are of interest.

They include both the actual and probable reserves, and have been classified
according to kinds of coal as follows:

A. Coals with large percentages of fixed carbon, including, besides the
anthracites, the dry, non-coking coals that burn with a short flame.
and C. Bituminous coals, including some of the non-coking, but freeThe cannel
coals, and the coking coals burning with a long flame.
coals and coals with very high volatile are under C.
D. Subbituminous coals, and the lignites.
burning
The first mention of coal in the United

probably in the journal of Father Hennepin, who in
"
"
cole mine
on the Illinois River
1679 recorded the site of a
Production of Coal.
States
is
near the present city of Ottawa, Illinois, but the first actual
mining appears to have occurred in the Richmond basin, Virginia,
about seventy years

i
The Coal
later.
Resources of the
Ltd., Toronto, 1913.
World.
The
first
Vols.
I, II,
records of production are

III
and
Atlas.
Morang &
Co.,
COAL
COAL RESERVES OF THE WORLD
53
(IN
MILLION TONS)
ECONOMIC GEOLOGY
54
and in 1807, 55 tons were shipped to Columbus, Ohio.

The regular production dates from 1814.
The phenomenal growth of the coal mining industry is well
shown by the diagram (Fig. 24).
The production of the individual states since 1910 is given on
in 1790,
page
55.
Grouping the output by regions, the overwhelming importance

of the Appalachian region is well seen.
PRODUCTION OF COAL IN UNITED STATES BY REGIONS FROM 1910-1914
IN SHORT TONS
COAL
OSOOOCO CO
t^- O
OSOC^HOOtM
^-"tCC^^CO
"
2 3C
-. -- 2-.-.
S"
C^ -f t- *C OS
^
C Ci *2 "f
O5 CO CN OC
*
O3
floe M SH^
OS
C CO CO to
" cc t^-c
cs V eo
oT
c;
frt
"
eo"
co
rf
cr.
tc;oiOb*ecO
,> co ^" oc
"
oi
t*
okM^cSec^/
? t- CO*^"
t~
C-l"
C1
<
88
o c: co
"
-.1"
'
M5**oo^cSooi5obai
CCG^^COCNCO OCCO
O CO W CO OC
O^" M ^* QC f-
to <N >n o'

rf
>c
CMti
t* CO t^
CC
-.
O
22
:-~
_Neccîacc^c3co;c^_r*c^c^-ô
o c e-J o <*" ecs" ^ oj cs"
^" 2 ^"
S3
W5 ^H
<O CO
~f-> **" i-
OJ CN
55
c^
o *c
CO CM
t^-
x
oo
^
"
CC
^"
C5 CN
C3
C^
c^j
W CO
t^- t^. t^-
OS
fo^^cici
I
<o
"
??!'
'
s
j
oo co oc r* os
'
OC
C-1
CO CO
c:
t r* so co
cs
t-
cot^.coe-ic^-:
OC^l
Ttt
*c
5
oo
Tf^
c
c
c
I^-iC'M'
CNOS
2r
c
t*-
ci ^
^
^ oM
1
lt^-O' 'iCGCNOC'
'
cs r* ^* oc w oc
T
c: co -*
oo N r- -^ oc -^
g'cJ
-^ re
8o^Ht
25^,t
<o c^
m ao w >-
coco
fe^
ClQCtÔJO
cccoe-ic^r-cicocccoiM
CCdC:'^'XCSCOCOGCCClOCCÔ
c^cco"r^-"-*f"c>iut'i^'
-CCM'-^^^
r^"*
-^^
CO
<7
c^c
Ci
5W5
CO
*- OO "5
OS CO
sa
'
C
2
.S
e c
'2i*M=? o c">. a 8 -Sc'^-.s -lIlllillsflMililiilliliiflj

'
Ef-S
oi
ECONOMIC GEOLOGY
56
Exports are also made by sea to the

provinces.
to Central and South America and elsewhere.
West
Indies,
The imports are principally from Australia and British

Columbia to San Francisco, from Great Britain to the Atlantic
and Pacific coasts, and from Nova Scotia to Atlantic coast points.
The
statistics since
1909 are given below:
COAL OF DOMESTIC PRODUCTION EXPORTED FROM THE UNITED STATES

1909-1914, IN LONG TONS
YE\.R
COAL
PRODUCTION OF COAL IN CANADA, 1912-1913, BY PROVINCES
57
ECONOMIC GEOLOGY
58
FIG. 24.
Curve showing
relation of increase in population in the United States

(U. S. Geol. Surv., Min. Res. 1914.)
to production of coal, 1856-1914.
COAL
VALUE OF PRODUCTS OBTAINED IN MANUFACTURE OF COKE
OVENS IN 1913 AND 1914
59
IN
RETORT
ECONOMIC GEOLOGY
60
ggg
H
&
O
-Z
C"
COAL
61
PEAT
So much attention has been attracted to this material
Origin.
in the last few years that it seems desirable to treat it as a
separate
topic, and partly so because it can be used for other purposes than
fuel.
Peat (128)
may
be defined as " vegetable matter in a partly de-
composed and more or
less disintegrated condition," and

represents
of the "dark-colored or nearly black soil found in
and
much
bogs
The dry peat may be very fibrous and light colored,

or compact, structureless, and dark brown or black.
If wet, it
contains as much as 80 to 91 per cent or even more water. As
previously mentioned (p. 1) it is produced by the slow decay, under
swamps."
water, of accumulated plant remains.
Diagram showing how plants fill depressions from the sides and top, to
form a peat deposit.
1.
Zone of Chara and floating aquatics. 2. Zone of
5. Advance
Potamogetons. 3. Zone of water lilies. 4. Floating ssdge mat.
6. Shrub and Sphagnum zone.
7. Zone of Tamplants of conifers and shrubs.
arack and Spruce. 8. Marginal Fosse.
(After Davis, Mich. Geol. Sun., Ann.
FIG. 25.
Kept, for 1906.)
The two
essential conditions for peat formation are (1) restricted
access of air to impede growth of decay-producing organisms,

(2) abundance of water to permit profuse plant growth.
This decay
is
and
accomplished mainly through the agency of fungi
air-requiring bacteria which break down the tissues, the decay

involving decrease in bulk, darkening in color, and liberation of
and
gaseous constituents.
Both moisture and
air are essentials to this
process.
is essential to peat formation, and
formed by accumulation of plants in the spot where they
Since an abundance of water

as
it is
But peat may

requires plants of a water-loving nature.
flat
or
in
moist
form in lakes or ponds, or
areas, and
depressions
grew,
it
hence plants adapted to these different sets of conditions being

1
If this
known
material contains too
as muck.
much
mineral matter to burn freely,
it is
differ-
technically
ECONOMIC GEOLOGY
62
follows that the product
it
ent,
may come
from more than one
kind.
be formed in lakes or similar depressions by aquatic

plants, including minute algae, building up a deposit from the
bottom and around the sides, in water shallower than 15 feet. The
extension of this deposit into deeper water and building up of the
Peat
may
bottom permits growth
of aquatic seed plants, resulting in estabThese are characterized (127)

lishment of characteristic zones.
the
pond weeds, Potamogeton, next to the deepest water;
by (1)
of this the pond lilies; (3) the lake bulrush, Scirpus;
shoreward
(2)
and
(4)
sedge.
sedges
the amphibious sedges, especially the turf-forming slender

In some localities some of the zones may be absent. The
may
also extend
outward from the
shore, forming a floating
mat, which
may cover the entire surface of the pond, and become

covered by a growth of shrubs and even large trees, although the
mat may not be more than 4 or 5 feet thick.
Peat may also form on moist, flat, or sloping surfaces, in depresfrom which standing water is naturally absent, provided the
plant remains are kept saturated with water, which they hold there
In such situation plants of the rush, grass,
partly by capillarity.
sions
This type of peat accumuheavy rainfall and moist atmos-
sedge type, or sphagnum are important.

lation flourishes best in regions of
and the deposit shows an irregularly stratified structure,

but more uniform character than the filled-basin type first described,
whose structure is more uniform below the original water level, but
whose upper 3-5 feet is nearly always of different structure and comSome bogs may be of composite origin.
position from that below.
:
phere,
The present surface vegetation of the bog does not necessarily

indicate the kind of plant from which the peat was formed.
An interesting type of peat is that found in salt marshes, of which
there are thousands of acres along the Atlantic coast, these marshes
being poorly-drained plains subject to frequent overflow by the sea-
water.
the peat
Studies
by Davis
of the
Maine marshes
(128) indicate that
"
fresh-water origin below a relatively thin

stratum of salt-water peat, or else made up entirely of plants similar
is
either of
to those growing
on the marshes to-day at about high
The suggested explanation
tide level."
that the fresh-water peat has been

formed in fresh-water bogs situated on a slowly sinking coast, while
the upper or salt-water peat formed when the land was low enough to
is
permit an influx of salt water, thus permitting the growth of only

such plants as could stand it.
COAL
63
The
fresh-water peat may be of fuel value, but that formed

wholly by the growth of salt-marsh plants is too full of fine silt
and mud tidal deposits to be of marketable character. (See
analyses, p. 9.)
Uses of Peat (119, 126, 127).

The main use of peat is for fuel,
it has never been extensively used in America for this purpose.
but
number of experimental plants have been built in Canada, but

most of them have not been successful nor have any been so in the
United States. The failure may have been due to lack of capital,
improper machinery, or lack of experience. Since a detailed discussion of peat-fuel technology is beyond the limits of this work,
those wishing to follow it up are referred to Nos. 126, 127, 128, of
the bibliography.
For fuel purposes the peat may be used in air-dried form as it

comes from the bog, pressed into blocks (machine peat), in briquettes
with or without binder, or in gas producers. There is only one
peat briquetting plant in Europe (1913), but peat powder has
been successfully used in special burners. Peat fuel has been
used in European glass factories.

Of importance is the use of the more fibrous kinds of peat as
a material for bedding for stock and for packing, as well as for
deodorizing and disinfecting. Those varieties of powdered peat
which are rich in nitrogen are dried and sold for filler in certain
artificial fertilizer, and although a use of recent origin
"
"
is the finer matter separated
Mull
seems to be growing.
from moss litter by screening, and sold for deodorizing, filtering,
kinds of
it
disinfecting,
and packing purposes.
The manufacture
of fertilizer filler is at present the largest

industry based on peat in the United States.
Those peats having a strong fiber can be used in the manufacture
of cloth and paper, but there is only one American plant turning
out this class of product. Peat can also be utilized for making
ethyl alcohol, and also for pressing into a structural material
resembling wood.
Peat baths have long been used for medicinal purposes in
1
Germany and Austria, but only recently have they been tried
States.
in the United
Those regions possessing
Distribution in the United States.
to
be of commercial value
and
size
sufficient
of
depth
peat beds
of
the
outside
lie mostly
coal-producing territory.
1
H. Schreiber, Moorkulturstation
in Sebastiansberg, Vol.
XII, 1910.
ECONOMIC GEOLOGY
64
Davis states that workable beds are found in
many
states
lying north of the Ohio and east of the Missouri rivers, in the
coastal portions of the Middle and South Atlantic and Gulf
States, and in the narrow strip along the Pacific coast from
southern California northward to the Canadian boundary.
Production of Peat.
Few statistics showing the production
of peat in the United States are available.
The production and imports for 1913 and 1914 are given
the United States Geological Survey as follows:
by
PRODUCTION, IMPORTS, AND CONSUMPTION OF PEAT IN THE UNITED STATES

IN 1914, IN
USE
SHORT TONS
COAL
65
REFERENCES ON COAL
ORIGIN.
1.
Ashley, Econ. Geol., II: 34, 1907.
(Maximum
rate of deposi-
Natural History of Coal, 1911. 2. Campbell, Econ.

3. Clarke, U. S. Geol. Surv., Bull. 491:
Geol., I: 26, 1905.
(Origin.)
4. Bowling, Can. Min. Inst. Jour., XII, 1909 and XIII:
705, 1911.
(Chemical changes in coal formation.) 4a. Jeffrey, Jour.
180, 1911.
la. Arber,
tion.)
XXIII:
Geol.,
CLV:
353,
1915.
218,
Ann. Kept.:
Pa.,
1843.
(Origin.)
1885.
95,
(Upright
5.
Lesquereux, 2d Geol. Surv.
6. Lyell, Amer. Jour. Sci.,

(Origin.)
trees in coal.)
7. Moffat, Amer. Inst.
XV: 819, 1887. (Change of mine prop to coal.)

Potonie, Klassifikation und Terminologie der rezenten brennbaren
Biolithe und ihrer Lagerstatten.
Prussian Geol. Surv., Berlin, 1906.
9. Potonie, Die Entstehung dei Steinkohle, Berlin, 1907.
10. Smith,
Min. Engrs., Trans.
8.
Econ. Geol.,
I:
coal
Geol.,
beds.)
Ill:
1905-1906.
581,
II. Stevenson, Proc.
Amer.
(Discussion of Campbell's theory.)

(Formation of
31, 1913.
Phil. Soc., LII:
lla. Stutzer,
292,
Kohle, Berlin, 1914. 12. White, Econ.

(Problems in coal formation.) 12a. White
1908.
and Thiessen, Bur. Mines,
Bull. 38, 1913.
(Origin
and microstructure.)
Campbell, Econ. Geol., Ill: 134, 1908. 14. Camp14a. Campbell, Amer. Inst. Min. Engrs., Trans. XXXVI: 324, 1906.
bell, Econ. Geol., VI:
(Proximate analysis.) 15. Collier,
562, 1911.
U. S. Geol. Surv., Bull. 218, 1903. 16. Dowling, Can. Min. Inst.,
Quart. Bull., No. 1: 61, 1908. 17. Frazer, Amer. Inst. Min. Engrs.,
Trans. VI: 430. 18. Grout, Econ. Geol., II: 225, 1907. 19. Parr,
CLASSIFICATION.
III.
13.
Geol. Surv., Bull.

'
1906.
3,
20. White,
U. S. Geol. Surv., Bull.
382, 1909.
COMPOSITION, STRUCTURE, ETC.

(Structure of coal basins.)
21. Bain,
Jour.
Geol.,
Ill:
22. Fieldner, Bur. Mines.,
646,
1895.
Tech. Pap. 76.
(Sampling and analysis.) 23. Campbell, Econ. Geol., Ill: 48, 1907.
(Value of coal mine sampling.) 24. Catlett, Amer. Inst. Min. Engrs.,
Trans. XXX: 559, 1901.
(Coal outcrops.) 24a. Grout, Econ. Geol.,
VI: 449, 1911. (Relation of texture to composition.) 246. Jeffrey,
Econ. Geol., IX: 730, 1914. (Composition and qualities.) 25. Lesley,
Manual of Coal and its Topography, Philadelphia, 1856. 26. Lord and
26a. Porter
(Analyses, texts, etc.)
others, Bur. Mines, Bull. 22, 1913.
and Ovitz, Bur. Mines Tech. Pap. 16, 1912. (Oxidation.) 27. Parr and
Hamilton, Econ. Geol., II: 693, 1907. (Weathering of
Econ. Geol., Ill: 265, 1908. (Test for coking
Pishel,
coal.)
coal.)
28.
28a.
Somermeier, Composition, Analysis, Utilization and Valuation. New

York. 29. Much general information in the special coal reports of
Iowa, Kansas, Indiana, and Ohio Geological Surveys.
22d Ann. Rep.,

MacFarlane, Coal Regions of
America, 700 pp., 3d ed., 1877, New York. 32. Nicholls, The Story
33. White, U. S. Geol. Surv., Bull.
of American Coals, 1897 (Phila.).
GENERAL AREAL REPORTS.

Ill:
7,
1902.
30.
Hayes, U.
(U. S. coal fields.)
S. Geol. Surv.,
31.
65.
(Bituminous field, Pa., Ohio, and W. Va.) 34. Series of papers
on the several coal fields of the United States, in U. S. Geol. Surv.,
22d Ann. Rept., Ill: 11-571, 1902, as follows: Ashley, p. 271. (East-
ECONOMIC GEOLOGY
66
ern Interior.) 35. Bain, p. 339.

(Western Interior.) 36. Hayes, p.
233. (Southern Appalachians.)
37. Smith, p. 479.
(Pacific coast.)
(Rocky Mountain
38. Storrs, p. 421.
anthracite.)
bell,
40. Taff,
and Hazeltine,
p.
p.
373.
125.
39. Stock, p. 6.
field.)
(Southwestern.)
Geol. Surv., 1900.

(Warrior field.)
Alaska:
Bulletins 260 and 285.
(Pa.
Camp-
Alabama:
(Northern Appalachians.)
42. Butts, U. S. Geol. Surv., Bull. 316: 76, 1907.

(Coosa field.)
Gibson, Ala. Geol. Surv., 1895.
Ann. Kept., Ill: 515, 1902.

Arizona:
and 284: 18, 1906.
41. White,
(Cahaba
field.)
43.
McCalley, Ala.
Also brief accounts in U. S. G. S.
45. Brooks, U. S. Geol. Surv., 22d
44.
46. Martin, Ibid., Bulls., 314:
47. Blake,
40, 1907,
Geol., XXI: 345, 1898.

(Deer Creek
240, 1904.
Amer.
Campbell, U. S. Geol. Surv., Bull. 225:

Arkansas: 49. Collier, U. S. Geol. Surv., Bull. 326, 1907.California: 50. Arnold, Ibid., Bull. 285: 223, 1906.
(Mt. Diablo range.)
51. Campbell, U. S. Geol. Surv., Bull. 316: 435, 1907.
(Stone Canyon.)
53. Also
52. Smith, U. S. Geol. Surv., 22d Ann. Kept., Ill: 479.
county reports in llth Ann. Kept. Calif. State Mining Bureau.
Colorado: 54. Storrs, U. S. Geol. Surv., 22d Ann. Kept., Ill: 421,
also special reports of U. S. Geol. Surv., Bulls. 297 (Yampa field), 316
(Durango field), 341 (N. W. Colo.). 55. U. S. Geol. Atlas, Folio No. 9.
Crested Butte area.) 55a. U. S. Geol. Surv., Bulls. 510
(Anthracite
and 471.
Georgia: 56. McCallie, Ga. Geol. Surv., Bull. 12, 1904.
48.
field.)
(General.)
Bull. 4:
Illinois:
187, 1906;
57. Parr, Grout,

also Ibid., Bull. 8:
and
others,
151, 1907,
111.
and
Geol.
Surv.,
Bull. 16:
177,
Geol. Surv., 22d Ann. Kept,, III: 271.Indiana: 59. Ashley, Ind. Dept. Geol. and Nat. Res., 23d Ann. Rept.,
Indian Territory: 60. Taff, U.
1899, and 33d Ann. Rept,, 1909.
1911.
58. Ashley,
U.
S.
S. Geol. Surv., 22d Ann. Rept,, III: 367, 1902; also Ibid., Bull., 260;
Iowa: 61. Bain, U. S. Geol. Surv., 22d Ann. Rept., Ill:
382, 1905.
Kansas:
339.
62. Hinds, la. Geol. Surv., XIX: 1909.
(General.)
63. Haworth and Crane, Kas. Geol. Surv., Ill: 13, 1898.
Kentucky:
Norwood, Ann. Rept., Inspector of Mines, 1901-1902. (Much

65. Moore, Ky. Geol. Surv., Ser. 2, IV, pt.
general information.)
XI: 423. (Eastern border and Western field.) 66. Ashley and Glenn,
64.
U. S. Geol. Surv., Prof. Pap. 49, 1906. (Cumberland Gap field.) 67.
Crandall, Ky. Geol. Surv., Bull. 4, 1905, also Hoenig, Ibid., 4th ser.,
I: 79, 1913.
68. Stone, U. S. Geol. Surv., Bull.
(Big Sandy Valley.)
316: 42, 1907.
(Elkhorn field.) 69. For analyses, see Ky. Geol.
new series, Chem. Rept., etc., pts. I, II, and III. 69a. Dil(Black Mtn.
worth, Amer. Inst. Min. Engrs., Bull. 62: 149, 1912.
696. Fohs, Ky. Geol. Surv., Bull. 18, 1912.
Louisiana:
district.)
Surv.,
70. Harris,
Prelim. Rept. on Geol. of La. for 1899:
134.
Maryland: 71. Clark, Md. Geol. Surv., V, 1905.

72. Lane, Mich. Geol. Surv., VIII, pt. 2.
Mississippi:
Miss. Geol Surv., Bull. 3, 1909; also Econ. Geol., Ill:
(Lignite.)
Michigan:
73. Brown,
219,
1908.
Winslow, Mo. Geol. Surv., 1891: 19-226.

1912.
74a. Hinds, Mo. Bur. Geol. Mines, 2d ser. XI:
(General.)
Montana: 75. Rowe, Univ. of Mont., Bull. 4. (General.) 76.
Weed, Eng. and Min. Jour., LIII: 520, 542, and LV: 197. (Great
(Lignite.)
Missouri:
74.
COAL
Falls
and Rocky Fork
fields.)
67
77. Scattered
on individual
and 541 of U. S.
papers,
fields in Bulls. 225, 285, 316, 341, 356, 390, 471, 531,
Geol. Survey.
Nebraska: 78. Barbour, Neb. Geol. Surv., I: 198,
1903.
Nevada: 79. Spurr, U. S. Geol. Surv., Bull. 225: 289, 1904.
New Mexico: 80.
Hance, Ibid., Bull. 513: 313, 1913. (Coaldale.)
Johnson, Sch. of M. Quart., XXIV: 456. (Cerrillos.) 81. Schrader,

U. S. Geol. Surv., Bull. 285: 241, 1906. (Durango-Gallup.) Other
papers in Ibid., Bulls. 225 (White Mountain region), 285 (Engle), 316
(Durango-Gallup, Sandoval County, Lincoln County), 341 (DurangoGallup), 471 (Tijeras), 541 (Sierra Blanca). 82. Storrs, U. S. Geol.
22d Ann. Kept., Ill: 415, 1902.

North Carolina: 83. Woodworth, U. S. Geol. Surv., 22d Ann. Kept., Ill: 31, 1902. 83a. Stone,
U. S. Geol. Surv., Bull. 471 137, 1912. (Dan River.)
North Dakota:
Surv.,
84. Babcock,
N. Dak. Geol. Surv.,
1st Bien. Rept,, 1901: 56.

85.
86. Storrs, U. S.
Wilder, Econ. Geol., July-Aug., 1906.
(Lignites.)
Geol. Surv., 22d Ann. Rept., Ill: 415, 1902. 87. Leonard, U. S. Geol.
Mont, lignite area.) 88.
Surv., Bull. 285: 316, 1906.
(N. Dak.
89.
Smith, U. S. Geol. Surv., Bull. 341: 15, 1908.
(Sentinel Butte.)
Burchard, Ibid., Bull. 225: 276, 1903. (Missouri Valley.) Ibid.,
Bull. 471.
(Fort Berthold), Bull. 531 (Williston), Bull. 575 (Standing
Rock and Cheyenne River Reservation.)
Ohio: 90. Orton, Ohio
Geol. Surv., VII: 255. 91. Lord, Bownocker, Somermeier, Ohio Geol.
r
92. W hite, U. S. Geol. Surv., Bull. 65,
Surv., 4th ser., Bull. 9, 1908.
1891.
Oklahoma: See Indian Territory.
(Stratigraphy.)
Oregon:
93. Smith, U. S. Geol. Surv., 22d Ann. Rept., Ill: 473, 1902.
94.
(Coos Bay.) 94a.

Diller, Ibid., 19th Ann. Rept., Ill: 309, 1899.
(Eden Ridge.) 946.
Lesher, U. S. Geol. Surv., Bull. 541: 399, 1914.
w. Ore.) 94c. Williams,
1914.
(s.
Diller,
Ibid., Bull. 546:
130,
Min. Res. Ore.,
I,
No.
1:
28, 1914.
(Squaw Creek
basin.)
vania: 95. d'Invilliers, 2d Pa. Geol. Surv., Rept., 1885 and 1886.
Pennsyl(Pitts-
burg region.) 96. MacFarlane, Coal Regions of America, 3d ed., New

of 2d Pa. Geol. Surv. contains many
York, 1877. 97. Report
analyses; see also county reports of same survey. 98. Lesley, Final
Summary Rept., Ill, pts. 1 and 2. (Stratigraphy.) 99. Hice and
99a. Gardner,
others, Top. and Geol. Surv., Pa., 1906-1908: 218, 1908.
(Broad Top field.) 100. Stock, U. S. Geol.
Ibid., Rept. 10, 1913.
101. White,
(Anthracite.)
Surv., 22d Ann. Rept., Ill: 61, 1902.
Campbell, Hazeltine, U. S. Geol. Surv., 22d Ann. Rept., Ill: 125,
Numerous references to coal in U. S. G. S.
1902.
(Bituminous.)
bulletins and geologic atlas folios, for list of which see bibliography
Rhode Island: lOla. Ashley, U. S. Geol.
in Min. Res., 1907.
South Dakota: 102. Todd, S. Dak. Geol.
Surv., Bull. 615, 1915.
See also U. S. Geol. Surv. Bulls. 499 and 575.
Surv., Bull. 1: 159.
Tennessee: 103. Hayes, U. S. Geol. Surv., 22d Ann. Rept., Ill:
104. Ashley and Glenn, U. S. Geol. Surv., Prof. Pap. 49,
227, 1902.
1906.
(Cumberland Gap.) 104a. Ashley, Resources Tenn., I, No.
Many brief references
5; Nelson, Tenn. Geol. Surv., Bull. 5, 1911.
Texas: 105. Durable, Bull, on
in U. S. G. S. Geologic Atlas folios.
106. Phillips, Univ. Tex. Min. Surv., Bull.
Lignite, Tex. Geol. Surv.
MM
ECONOMIC GEOLOGY
68
1902.
3,
1911.
and
(Coal
(Rio Grande
fields.)
1902.
415,
Vaughan, U.
Utah: 109. Storrs, U. S. Geol. Surv., 22d Ann. Kept.,

See also articles in U. S. G. S. Bulls. 285 (Sanpete
Ill: 367, 1902.
Ill:
106a. Phillips, Univ. Tex. Bull. 189,

S. Geol. Surv., Bull. 164, 1900.
108. Taff, U. S. Geol. Surv., 22d Ann. Kept.,
lignite.)
107.
(Analyses.)
County, Weber River, Book Cliffs), 316 (Pleasant Valley and Iron
County), 341 (n. e. Utah, s. w. region), 371 (Book Cliffs), other fields
Vermont: 110. Hitchcock, Amer. Jour. Sci.,
in Bulls. 471 and 541.
xv:
ii,
1853.
95,
at
(Lignite
Mineral Resources Virginia:
Woodworth, U.
S. Geol. Surv.,
mond
113. Campbell,
basin.)
Brandon.)
336,
1907.
111. Watson,
Virginia:
112. Shaler and
(General.)
19th Ann. Rept., II: 393, 1898.

(RichU. S. Geol. Surv., Bull. Ill, 1893.
114. Landes and Ruddy, Wash.

Washington:
(Big Stone Gap.)
114a. Evans, Wash. Geol. Surv., Bull.
Geol. Surv., II.
(General.)
(King Co.) See also U. S. Geol. Surv., Bulls. 474, 531, and
3, 1913.
West Virginia: 115. White, W. Va. Geol. Surv., II, 1903. (Gen115a. White, W. Va. Geol. Surv., Bull. 2: 209, 1911. (Analyses.)
Wyoming: 116. Storrs, U. S. Geol. Surv., 22d Ann. Rept., Ill: 415,
541.
eral.)
117. U. S. Surv., Bulls. 225 (Bighorn Basin), 260

(General.)
(Black Hills), 285 (Uinta County), 316 (Central Uinta County, Lander
field, Carbon County, Laramie Basin), 341 (Bighorn Basin, Sheridan
1902.
Snake River, Great Divide Basin, Rock Springs, Casper
district, Little
Douglas
W yo.)
T
(s.
w.
118. Veatch, U. S. Geol. Surv., Prof. Pap. 56, 1908.

fields, see Ibid., Bulls. 471, 499, 531,
district).
For other individual
and 543.
Canada: 118a. Dowling, Can. Geol. Surv., Mem., 59, 1915. (General.)
1186. Porter and Durley, Mines Branch, Investigation of Canadian
118c. Cairnes, Can. Min. Inst., XV: 364, 1913.
(Yukon.)
Coals, 1912.
HSd. Clapp, Can. Geol. Surv., Mem. 51, 1914. (Nanaimo.) 118e.
(Man., Sask., Alta., and e.
Dowling, Ibid., Rep. No. 1035, 1915.
Brit. Col.)
118/.
1180. Dowling,
Dowling,
Ibid.,
Ibid.,
Mem.,
69,
1911.
Mem.,
8,
1915.
(Brit.
(Edmonton
Col.)
118ft.
field.)
Hudson,
Mines Branch, Spec. Birc., 1913. (Sydney field.) H8i. Mallock,

Can. Geol. Surv., Mem., 9-E., 1911.
(Bighorn Basin, Alta.) 118.;'.
Poole, Ibid.,
XIV:
Pt.
M.
(Pictou
field.)
REFERENCES ON PEAT
119. Ries,
and uses
for
p.
N. Y. State Museum, 54th Ann. Rept., 1903.
in general,
Bibliography.)
(N. Y., Origin

120. Carter, Ont. Bur. Mines, Rept.
121. Shaler, U. S. Geol. Surv., 12th Ann. Rept.,

(General.)
122. Roller, Die Torfindustrie, Vienna,
(Peat and swamp soils.)
123. Wilder and Savage, la. Geol. Surv., Bull. 2, 1905.
124.
(la.)
1903.
311.
1889.
Ind. Dept. Geol. Nat. Res., 31st Ann. Rept., 1906.

125. Parmelee and McCourt, N. J. Geol. Surv., Rept., 1905: 223, 1906. 126.
Nystrom, Dept. Mines Can., Spec. Bull., 1908. (Manufacture and uses.)
127. Davis, Mich. Geol. Surv., Ann. Rept., 1906: 105, 1907.
(General
Taylor,
and Mich.)
(Maine,
and Davis, U. S. Geol. Surv., Bull. 376, 1909.

129. Parsons, N. Y. Geol. Surv., 23d Ann.
analyses.)
130. Taylor, Ind. Dept. Geol. Nat. Res., 31st Ann.
(N. Y.)
128. Bastin
many
Hept., 1904.
COAL
Kept., 73,
(Origin.)
1906.
(Ind.)
131. Davis,
132. Davis, Econ. Geol.
69
Bur. Mines, Bull. 38:
V: 623, 1910.
(Salt
165,
133. Dachnowski, O. Geol. Surv., 4th ser., Bull. 16, 1912.

(Ohio.)
Harper, Fla. Geol. Surv., 3rd Kept.: 197, 1910. (Fla.)
For Canada see reports issued by Mines Branch, dealing especially
technology and digging of peat. Among them: 135. Haanel, Rept.
Values of Peat for Gas and Power in Producers. 136. Anrep. Canad.
266, Canadian Peat Bogs
and Peat Industry.
1913.
marsh formation.)
134.
with
299.
Rep.
CHAPTER
Under
Introductory.
head are included four well-known
natural gas, petroleum, mineral tar or maltha, and
viz.
substances,
this
II
carbon and hydrogen

compounds. In addition they
hydrocarbons
contain
such
as
many impurities,
may
sulphur compounds, oxidized
and nitrogenous substances, etc. whose exact nature may be doubtful.
all
asphaltum,
essentially
compounds
of
or mixtures of such
The hydrocarbons
are divisible primarily into a number of regular

series, each of which has a generalized formula as indicated below.
1.
CnHi'n+2
6.
C n H2n-8
2.
CnHin
7.
3.
C n H2ii-2
CnH 2n _4
8.
CnH2n-]0
CuHon-is
18.
CnH.2n32
4.
5.
Members
CnH2n-6
of the first eight series
have been discovered
in petro-
Of the above formulas, the first represents the paraffin

hydrocarbons, beginning with marsh gas or methane, CH 4 and
leum.
ranging at least as high as the compound C^H^. Methane is

gaseous, the middle members of the series are liquids, while the
members are solids, like ordinary paraffin. Members of the

second series are also important in petroleums, especially the olefine
higher
The
is represented in some
members.
The
fifth or benzine series
petroleums by
higher
occurs in nearly all petroleums, but not in large amounts.
Crude petroleum is a
Properties of Petroleum (4, 10, 12).
liquid of complex composition and variable color and density.
subseries.
third or acetylene series
its
It consists of
a mixture of hydrocarbons, mainly liquid, with

solid ones, the last being in solution. 1
some gaseous and

Oils
which contain
yield paraffin scales
temperature,
bodies,
1
dian
and
paraffin hydrocarbons, and which usually

the heavier distillates are subjected to a freezing
chiefly
when
be
said to have a paraffin base.

Those containing asphaltic
may
yielding on evaporation a residue consisting essentially of as-
For a r6sum of the different hydrocarbons discovered

oils,
also in
see F.
W.
Johnson and Huntley,
in
American and Cana-
Much general information

Principles of Oil and Gas Production, New York, 1916.
Clarke, U. S. Geol. Surv., Bull. 491.
70
PETROLEUM, NATURAL GAS, OTHER HYDROCARBONS
71
These two terms, though much

phalt, are said to have an asphaltic base.
used formerly, are rapidly falling into disuse; because some asphaltic oils
may also yield paraffin wax.
Sulphur may be present as a constituent of hydrogen sulphide, as free sulphur, or as organic sulphur compounds. The
first two, which occur for example in the Mexican, and in the
Gulf Coast oils of Texas and Louisiana, are not difficult to remove. Organic sulphur, such as occurs in the Lima, Ohio, and
the Ontario limestone oils, is more difficult to eliminate, even
though
in small
amounts.
Most petroleum
2 per
contains
cent, except in
some
some
nitrogen, but it rarely exceeds

California oils, where it may reach
10 or 20 per cent. 1
The
following are analyses of several petroleums from American
and foreign
localities
ELEMENTARY ANALYSES OF PETROLEUM
ECONOMIC GEOLOGY
72
the plane of polarization to the right, but some rotate

left, while others may be optically inert.
Petroleums commonly vary in
specific gravity
and .98, the following being some

American oils:
.8
SPECIFIC GRAVITY OF
STATE
of the
it
to the
between about
limits
shown by
SOME AMERICAN PETROLEUMS
73
74
ECONOMIC GEOLOGY
(XX3O H3d) XIVHJSy

(xxao Had) xivHdsy
75
ECONOMIC GEOLOGY
76
OoO
ooo
O
IN
TJ<
t-!
oj
T)!
^)i
*)i
TJI
oo
p O O
cJ
o o
us
co
to-H
r^M
-Ô
t-i
06
US
usoooopoo
'
COCOT>('-I
-H
US
(6
US
od
-as
=3
W TO
00
^l-HOCSC5TO-l^-<
fMiNTOOCOO-H
i
Qo
GO
-H
(N
coo
l-Sg-i.lt
gs^so
C Q O Q CQ
-H
oooooooooot-oo
.
11
B O
a
S
s
J
88
H3d) 11VHd8y
88
77
O co-o
(J.X3O H3d)
32
j."i
in. i.i
oOOS
oOSl
(juaa aad)
~:i
rn\
-IXN3Q
92
co
O
co
ci
ooooo
l-H
w
ogioadg
ifl
AÎABJQ
,il(l.
),x!^
o S
S^2^
t>.
t>-
K5
i-i
"f
Qo
-"3
X^
BO
fcas
AH
ogioadg
j-3oT
>U2
.Ô"
^J
OJ
1^8,00
DO
78
ECONOMIC GEOLOGY
ANALYSES OF NATURAL GAS
79
The following table brings out the essential differences between natural
gas and other fuel or illuminating gases.
Analyses of natural and manufactured gases.
ECONOMIC GEOLOGY
80
to.
The general substance of these, and several others' hypotheses is that surface water has percolated downward through the
earth's crust, where on reaching the heated interior it becomes
converted into steam, which, attacking the carbide of iron,

forms hydrocarbons, which make up the oil and gas.
From a purely chemical standpoint, this theory is reasonable,
and the production of hydrocarbons by this method has been done
If
experimentally, but it does not accord with geologic facts.
were
formed
in
this
we
should
it
to
find
manner,
expect
petroleum
widely distributed through the oldest rocks of the earth's crust.
On
the contrary, hydrocarbon compounds like oil, gas, and asare

In Ontario, a
practically unknown in crystalline rocks.
phalt
found in them, but it is significant that

which was probably originally petroleum, occurs in rocks which may be metamorphosed sediments. A
second case is found in California (17), where oil occurs in a
much-folded crystalline schist, but its associations are such that it
may have been derived from neighboring sediments.
hard compressed asphalt
is
this material (Anthraxolite)
A possible point in favor of the derivation of oil and gas from carbides
has been noted by Becker (1), who has called attention to the fact that
the irregularities of the curves of equal magnetic declination are strongly
marked in the principal oil regions. While the agreement is not a very
There are, however,
close one, it is most marked in the Appalachian field.
some systematic irregularities, as in the New Jersey magnetite regions,
which are not known to contain any oil. Becker believes that the coincidence between the petroleum occurrences and local disturbances of the
compass are too numerous to be attributable to mere accident, and that
there must be a direct or indirect historical connection between the two
in the regions of coincidence, thus suggesting the possibility of
being derived from iron carbides.
Tarr (12a), however, disputes Becker's conclusions, pointing out: (1)
That the isoclinals or lines of magnetic dip do not show any evidence
of disturbances due to magnetic masses in the oil regions;
(2) that the
phenomena
the
oil
is a shifting of the isogonics or lines of magnetic declination,

indicating that the origin of this variation is not due to a stationary mass;
and (3) the magnetism of iron is lost at high temperatures, hence it must
secular variation
comparatively shallow depths to be magnetically effective.

A second inorganic theory advocated by several,
Theory.
and in recent years expounded with great vigor and detail by E. Coste
exist at
Volcanic
the theory of volcanic origin of the hydrocarbons.

believes that all hydrocarbons cannot be of animal or vegetable origin, but must be of volcanic derivation for the following reasons:
(2d, 3a), is
Mr. Coste
2. Vegetable
1. Animal remains are never entombed in rock formations.
3. Further distillaremains in rocks decompose into carbonaceous 'matter.
4. Gaseous
tion of carbonaceous matter has not taken place in nature.
81
liquid, and solid hydrocarbons are products of volcanic emanations.

5. Oil
and gas are under strong pressure, and hence must be of volcanic origin,
for nothing else could produce this pressure.
6. In some oil fields heated
gas and water are met with. 7. Oil and gas fields are located along faulted
and fissured zones of the earth's crust, parallel to great orogenic (mountainmaking) and volcanic dislocations. 8. Oil, gas, and bituminous matter
are never indigenous to the strata in which they are found. 9. The density
of the rocks precludes possibility of anything but volcanic pressure having
them upward.
The arguments against some of these points may be mentioned under
the same numbers: 1. Animal remains are entombed in rocks, otherwise we
forced
could not have fossils of those lacking hard parts. 2. Vegetable remains in
rock have been proven to decompose into hydrocarbons, as evidenced by
natural gas supplies found in glacial drift; moreover, some coal seams have
oil seepages.
3. While hydrocarbons are known to occur in some volcanic
emanations, they might be formed by the direct union of carbon and hydrogen of these gases, or have been distilled out of sedimentary rocks through
which the lava passed. Moreover, they are frequently formed from decaying vegetable matter. 5. The pressure may be due to the natural expansive
force of the gas.
7. Oil and gas fields are sometimes found in regions of
but little disturbance, as Illinois, Medicine Hat, Alberta, etc. 8. This may
be true, but they are often clearly shown to have come from adjoining beds.
9.
If
volcanic pressure forced this oil and gas up through many feet of
why were they not forced all the way to the surface ?
dense rock,
also add that the restriction of oil and gas to sedimentary

not in accordance with a volcanic origin, neither is the decrease in
pressure which most wells show with time.
One may
rocks
is
This considers that petroleum has been

Organic Theory.
formed by the decomposition of organic matter buried in the
rocks, although the exact changes involved are
somewhat un-
certain.
But even though many are

origin,
they
difier as to
in agreement on the theory of organic

whether the oil came from animal or
vegetable matter.
Adherents of the former view include Hofer, 1 Newberry, 2 Hunt, Zaloziecki,
Engler,
and
others, while
among
those of the latter are numbered
Lesquereux, Phillips, Kramer, Spilker, and others.
Perhaps the majority of geologists and even others have

unconsciously assumed that petroleum has been derived from
land plants, and while in some cases this may be so, some rather
1
Proc. Manchester Lit. Phil. Soc., Ill:
Geol. Sun'. Ohio, 1878, Pt.
"Dingler's Polytech. Jour.,
I:
136,
and Das Erdol,
CCLXXX:
69,
85 and 133;
1203.
4
Redwood, Petroleum and
its
p. 118.
125 and 174.
Products, 1906, p. 259.
Chem.
Zeit.,
XV:
ECONOMIC GEOLOGY
82
weighty objections can be urged against

following
1.
oil.
These are the
it.
There
is
a general lack of association of coal or lignite and

lignite or carbonized wood is found with oil it
Where
2.
has lost none of
its essential
constituents.
3.
There
is
a great
chemical difference between lignite tar oils and natural petroleums. 4. It requires a high temperature (geologically speaking)
wood into liquid bitumen, and leave no trace of its

1
5. An argument of doubtful weight is that
structure.
original
limestones, being of marine origin, the oil in them could not be
to convert
derived from land plants.
The following arguments may be mentioned in favor of the

derivation of petroleum from marine plants such as seaweeds:
1.
Saline water associated
with some
oils
carries
iodine. 1
2.
Certain seaweeds found on the coast of Sardinia become covered
with an oily coating while decomposing.-3 3. In some localities

the diatom cases found in rocks are known to contain small
globules of oil, which have in some regions been regarded as
a source of petroleum (19). 4. The so-called algal remains of
bog-head coals were formerly regarded as evidence of marine
origin,
now recognized as spores,

petroliferous or highly bituminous,
in some form or other are the mother
but these minute bodies are
the coals rich in
them being
and according to Jeffrey

substance of
or gas.
also considered that the oil
oil
Some have
rived, in part at least,
may have
from animal remains, the
oil
been de-
thus having
a dual origin.
Some have claimed
that the optical activity of oil shows it

undoubted organic origin (l), for the reason that mai y
petroleum products have the power of rotating the plane of
polarization of light, as is done by sugar, lactic acid, and other
organic compounds. These optical phenomena are not shown
6
by inorganically synthesized petroleum, and hence it is argued
which
it
to
is
believed
to be due are only of
substances
that the
These
substances
are
derivation.
cholesterol, found in
organic
the fatty parts of animals, and phytosterol, found in plants.
to be of
1
Such a process would be likely to occur only where a bed of land plants was
approached by an intrusive.
2
Watts, Calif. State Min. Bur., Bull. 19: 202.
3
Redwood, Petroleum and its Products, 2d edition, I: 126, 142.
4
Econ. Geol., IX: 741, 1914.
s
C. A. Davis has recently identified algae in Utah oil shales.
6
Some natural petroleums are now found to be inert optically.

If
the
oils
are derived from animal
marine character,
83
and plant remains of
possible that the nitrogenous portions were

bacterial action soon after the death of the organit is
eliminated by
ism, and before
it became buried under sediments.

Subsequently
was produced by decomposition of the fatty matter of
the plants and animals.
Some geologists, including Orton (4)
and Newberry (Ohio State Agric. Kept. 1859) believed that the
the
oil
formation of petroleum has taken place at lower temperatures;

but others, including Peckham (6), have considered heat necIn the case of Appalachian oils the folding of the strata
essary.
supposed to have supplied this heat.

Oil is rarely found without
Mode of Occurrence. (6, 8, 9, 13).
some gas, but gas may occur without oil, and in either case
saline water may be present.
is
Kansas Crude
Oread
1
[
300'
"^
\
*
^
-J
Oread 3
Sob7
Kansas Crude No.l
Oread No.l
Oread No.
Oread No.
ECONOMIC GEOLOGY
84
times vary in different parts of the same
thereby making correlation
field (Figs.
26 and 27),
difficult.
*^fj!
SiiOdg
NViNVAlASNNSd
The
NVIddlSSISSItM
thickness of
the producing
rock
("
pay sand
") varies
White, referring to West Virginia, refor good productive territory,

sufficient
as
of
sand
feet
5
gards
The
but thicker ones are found in the Appalachian field.
Illinois sands range from 2 to over 30 feet in thickness, while
that estimated for Spindle Top in Texas averages 75 feet. The
in the different
fields.

Kern River
field of
California
is
said to
85
have pay sands as much
as 100 feet thick. 1
The quantity of oil which a cubic foot of apparently dense rock

can hold is often surprising. White estimated that fairly productive sands may hold from six to twelve
pints of oil per cubic foot,
but that probably not more than three-fourths of the quantity
stored in the rock
is obtainable.
According to Day (53) it has been
customary to consider 10 per cent as near the average porosity of
the pay sand, with a latitude of variation from practically nothing in
damp shales to over 30 per cent in the most porous strata. The
degree of openness of the pores

of oil from the rock. 2
will,
however, govern the rate of flow
Pressure of Oil and Gas Wells.

Since both oil and gas usually
occur in the earth under pressure, any break in the porous rock or
reservoir which contains them allows them to escape, frequently
giving rise to surface indications, and the force with which oil and
gas oftentimes issue from a well indicates the pressure under which
they are confined.
and
ing tools
into the
It is
sometimes
sufficient to
casing, as well as to cause the
oil
blow out the
to spout
drill-
many
feet
air.
There are several remarkable cases of the amount spouted by these

gushing wells. One of these is the famous Lucas well at Beauir.ont, Texas,
which in 1901 for nine days gushed a 6-inch stream to a height of 160
This, however, is small comfeet, at the rate of 75,000 barrels per day.
pared with the records of some Mexican
when
oil wells.
Although many wells
does not usually continue long, and the oil then

has to be brought to the surface by pumping. The depth of the wells drilled
in the United States ranges from 250 to 4000 feet.
flow
first drilled, this
The maximum pressure which a well develops when closed has

been called rock pressure. As a result of his studies in the OhioIndiana field, Orton (42) found that the rock pressure was the same
as that of a column of water whose height was equal to the difference in elevation between the level of Lake Erie and that of the oil
localities,
He therefore considered it to be hydroThis theory, while apparently applicable in many

was found to be inadequate to explain the great pressure
shown
many
or gas-bearing stratum.
static pressure.
in
pressure
is
shallow wells.
thought by
many to
In these, as also in deep ones, the

be due to the expansive force of the
imprisoned gas.
Either the drilling of additional wells or a drain by excessive use
1
U. S. G. S., Bull. 394: 34, 1909.

Washburne, Amer. Inst. Min. Engrs.,
Bull., Feb. 1915.
ECONOMIC GEOLOGY
86
r-
QXX
j
SS
sag 3
O
O O
O^5*O
CO
8777
~
?
2
8 S
5 =
g
O5
28'a
z
"
-3
<
S
3
O
Hi
cc
ft
P
H
L-
~f Jx ^y*~* ~
OOOOOOMXOOOOMOO
15
p o o o
^
g Y 12
* ctc~.~
o OOOi
o o o
OOOOXXOO:
87
from wells already bored commonly causes a slow decrease in pressure in an oil or gas field. Thus in the natural gas region of Findlay,
Ohio, the rock pressure in 1885 was 450 pounds per square inch; 400
in 1886; 360-380 in 1887; 250 in 1889; 170-200 in 1890.
Some
West Virginia wells have shown a measured rock pressure of 1110
pounds per square inch and an estimated pressure of 2000 pounds.
It has been not infrequently noticed, however, that the opening
up of one or more wells close to a good producer may have little or
no effect on it.
The table on page 86 (53) gives the closed or rock pressure in
various fields, in different years. They are interesting, but lose
their comparative value as they do not probably in all cases
represent the
same
well.
Classification of Oil
and Gas Sands.

As early as 1861 T.
and
A.
Hofer, the Austrian
geologist,
Sterry Hunt, the Canadian
a GAS
1>
WATER
OIL
d CAPROCK
Section of anticlinal fold showing accumulation of gas,

(After Hayes U. S. Geol. Surv., Bull. 212.)
FIG. 28.
oil,
and water.
geologist, called attention to the fact that oil and gas occurrences
appeared to be associated with anticlinal folds, but the anticalled, was most fully developed
According to this theory, in folded areas
the gas collects at the summit of the fold, with the oil immediately below, on either side, followed by the water (Fig. 28).
It is, of course, necessary that the oil-bearing stratum shall be
clinal theory, as it
by
I.
C. White
came to be
(13).
capped by a practically impervious one.

the rocks are dry, then the chief points of accumulation
of the oil will be at or near the bottom of the syncline, or lowest
portion of the porous bed. If the rocks are partially saturated
If
with water, then the

uration.
oil
accumulates at the upper level of sat-
ECONOMIC GEOLOGY
88
In a tilted bed which

oil, gas, and water
is
and not so throughout,

arrange themselves according to
locally porous
may
the
their gravity in this porous part.

While the anticlinal theory has been found to apply in many
oil regions, some doubt has been raised regarding its possible
application in parts of southwestern Pennsylvania (6), and
even other
localities.
oil and gas appear to be associated

with anticlines, but there are others which are either related to
modifications of this structure, or to totally unrelated structures.
Many
occurrences of
Scale of .Miles
EXPLANATIONS;
Structure-Contour Lines, Showing
-9g
"Lay" of Gas Sands

OOil Well;
-ft-
FIG. 29.
Gas Well ;-^- Dry Hole;
Contour map
occurrence
showing
structural
dome
<(>Sho
of
"
sand,"
on a
Oklahoma.
of gas
in
Elevations of top of Berea Sand abor

-& Gas Well withjarge production
Gas Well nith small production
Drj Uole(Xo oil.or Gae)
'*
FIG. 30.
a
Gas pool coincident with
structural
terrace.
Class
Id.
(Clapp, Econ. Geol. V.)
(Clapp, Econ. Geol. VIII.)
The
I.
following classification has been suggested
Where
a.
6.
c.
anticlinal
and synclinal structure
by Clapp
(2c).
exists,
Strong anticlines standing alone.

(Eureka-Volcano Burning Springs
anticline
in
W'est Virginia.)
Alternating, well-defined anticlines and synclines.
(Appalachians, southern Indiana, and

Monoclinal slopes with change in dip.
(Southeast Ohio pools.)
Illinois, etc.)
PETROLEUM, NATURAL GAS. OTHER HYDROCARBONS

d.
Terrace structures.
e.
Broad
89
(Southwest Ohio.)
geanticlinal folds.
(Trenton limestone, Ohio.)

II.
Domes
or quaquaversal structures,
Anticlinal bulge type.

variation of I and merges into it.
(Rogersville, Pa., Geol. Atl. Fol. 146, a type case.)
Saline dome type.
a.
6.
(Southern Louisiana and Texas.)

Volcanic neck type.
c.
(Northeast Mexico.)
III.
Along sealed
IV. Oil
faults.
(Lompoc field, Calif.)

and gas sealed by asphaltic
deposits.
(Trinidad.)
V. At contact of sedimentary and crystalline rocks.

(Some Quebec and Ontario occurrences.)
VI. In joint cracks.
(Florence, Colorado,
and some California
fields.)
VII. In crystalline rocks.
Of these the representatives of Group
I are
by
far the
most
important.
Mode
of
necessarily,
Accumulation.
and perhaps rarely
While the
oil
and gas are not
are, indigenous to the rock con-
taining them, a difference of opinion exists as to whether they

have been transported long distances; indeed their source is
some under- or over-lying bed of shale.

According to the original anticlinal theory, the oil, gas, and
water were supposed to arrange themselves readily according
to their specific gravities, but this postulates a somewhat free
often indicated in
movement
to which
of these materials through the pores of the rocks,

many modern investigators hesitate to agree.
Capillary action and great rock pressure have been suggested

as possible operating forces, while Munn believes it is caused
by hydraulic action. According to his hydraulic theory (6),
oil and gas are concentrated into pools or pay
the
action of currents of underground water. These
by
Since these undercollect the oil and gas and push them along.
the diffused
streaks
ECONOMIC GEOLOGY
ground currents circulating through the rocks vary in the direction of their flow, there may be places where the meeting of
conflicting currents forms eddies or places of no movement.
It
at such points that the
is
accumulated oil and gas are held.

If the water is flowing through
the rocks under the influence
of capillarity alone, and conflicting
currents
there will
be
force the oil
more porous
FIG.
31.
through
Hypothetical cross-section
a volcanic neck in the oil
capillarity
is
are
absent,
tendency to
and gas into the

beds where the
too weak for the
fields of
water to follow.
Econ. Gcol. VII.)
The pressure of the oil is

ascribed to the expansive force
of the gas, which cannot dif-
Vera Cruz and Tamaulipas,

Mexico, showing one mode of occurrence of oil in formations having a
quaquaversal structure. (After Clapp,
fuse because of the saturation

of the surrounding rocks.
The association of oil with anticlines
is
thought to be due to the influence which these structures
exert on the water currents.
The difference in specific gravity
of
and water
oil
widespread
of oil against
tion
the
insufficient
to
account for the
fric-
by
developed
its
rock
through
passage
considered
is
movement
pores.
The
oil
then, held
and gas
in the
are,
rock,
not because of an impervious cap rock, but
by the
overlying
and
surrounding water mantle.
Washburne
(12c),
in
discussing the effect of

capillary action,
Hypothetical section in same district

showing a second and probably
less common mode of occurrence of oil in
quaquaversal structures. (After Clapp, Econ.
IG. 32.
as Fig. 31,
Geol., VII.)
points
out that the force drawing liquids

as the surface tension
of the liquid
into pores
varies directly
and inversely as the
di-
Water having a greater surface tension

ameter of the pore.
than oil, capillary action will exert a greater pull on it, and
there will be a tendency to draw it into the finest openings and

This results in concentrating the last
displace oil or gas.
in the coarsest spaces available.
91
two
Surface tension collects the small bodies of oil and

gas in a sand
into larger ones, which in case of gas are
capable of gravitative
displacement by water, so that the gas is lifted to the highest
If circulatory movements of the water
position it can reach.
bring oil to the water-gas surface, it is held there
surface
by
tension,
and the mass
of oil
may grow by accretion.
that in the absence of such conditions,

below water as it does in some fields.
oil
It is
claimed
might accumulate
The yield of an oil sand depends on the porosity, degree

and quantity extractible. Washburne uses a saturation factor
Yield of Sands.
of saturation
of 15 per cent for the average oil sand, but assumes that only 75 per cent of
the sand in a large pool is saturated and that only 60 to 75 per cent of this can
be recovered.
The
The
The
last
two
factors
must be varied to
above mean 524 barrels
suit conditions.
which is high.
yield per acre foot calculated for example, by Washburne, for the different sands of the Midway, California, field ranges from 32 to 1020. l
figures given
It
is
of oil per acre foot,
a difficult matter to estimate closely the average yield of oil in any field.
This may vary with the amount of supply, compactness
Life of a Well.
of pay sand, and gas pressure accompanying the petroleum.

It varies from
a few months to 20 years or more. Some wells may gush forth tremendous
quantities of oil and gas for a short period and then die down to almost
nothing. Others may yield moderate quantities, or perhaps only a few
barrels daily, for a period of years.
The average life of Pennsylvania wells
is seven years.
In all fields the production increases at first and then begins to drop off,
and the increasing production of the United States is due to the discovery
and development of new fields, whose production more than offsets the
decrease of the older ones.
As examples, the daily average production per well per day of New York
and Pennsylvania has fallen from a maximum of 207 barrels to 1.7 barrels.
The West Virginia production has dropped to 56 per cent of its maximum,
and Ohio and Indiana have shown a still greater decline.
On the other hand, Oklahoma and California are still increasing their
output.
Arnold in 1915 has figured the probable future supply from the United
States and Alaska at 5,763,100,000 barrels.
The
Distribution of Petroleum in the United States (Fl. X).
as figured by Arnold in 1915 together with their proven
areas and per cent exhaustion are as follows:
fields
Johnson and Huntley, Principles
of Oil
and Gas Production, 1916.
ECONOMIC GEOLOGY
92
PROVEN PER CENT

STATE.
Appalachian
AREA.
N. Y.-Pa
1400
350
100
W. Va
....
115
47
67
Ohio
535
500
83+
Indiana
400
70
297
Illinois
Mid-Continental
Kansas
Oklahoma
Louisiana
Gulf
87
50
Texas
156
California
Colorado
17
Michigan
Wyoming
31
Alaska
15
1
55+
Ohio
Ky.-Tenn
Ohio-Indiana
EXHAUST.
85
36+
42
22
34
33+
24
33f
58
2
Arnold, Econ. Geol., X, 1915.
These figures of course represent only the areas actually underby known pools, and not the entire area of the field.
This is the largest oil field in the United
Appalachian Field.
States, and includes portions of New York, Pennsylvania, Ohio,
West Virginia, Kentucky, and Tennessee.
The rocks are chiefly sandstones, with a few limestones, embedded
in and underlain by a great thickness of shales, while below these
are probably limestone beds.
The sandstones have a thickness of
probably 2000 feet or more, and in the middle and northern end of
the field range from the Conemaugh series nearly to the base of the
Devonian, and still lower in Tennessee and Kentucky. Their
lain
deposition represents a period of continuous sedimentation, with

the exception of the period between the Mauch Chunk and the
Pottsville, where an unconformity indicates an interval of uplift
and
It
erosion.
may
be said of the Appalachian
field as
a whole that the
oil-
bearing rocks occupy the bottom and west side of a large structural
trough, whose rim passes through central Ohio, then eastward south
of the Great Lakes
and then south along the western base

crosses western Pennsylvania
of the
where
Appalachians.
in
been
found
the
has
While
total
area
large quantity.
petroleum
outlined is probably over 50,000 square miles, the area actually unIt therefore
ECONOMIC GEOLOGY
94
derlain
by known
oil-bearing sands does not appear to exceed 3500
(53).
Within this great trough there are a number of subordinate folds

whose trend is northeast southwest, while still minor ones are found
with their axes at right angles to these.
Starbrick Well
Conway Well
Bradys Bend Well
Smith Well
5 Bedell
FIG. 33.
Map
showing
Well
Caseman No.l Well
lines of sections in Plate
XI.
The sandstones are, moreover, found
at increasing depths as one

so
that
those
goes southward,
outcropping in Ohio and New York
be
2000
or
3000
feet
below
the
surface in southwestern Pennsylmay
vania or West Virginia.

In this region there are a number of sandstones, the important
ones individually underlying many square miles. These sandstones are most numerous and attain their greatest thickness in the
center of the region.
The upper or younger sands are usually white, and may be
conglomeratic locally, while the older beds are brown or reddish,
and generally more uniform in texture.
At some
then
may
localities
two or more sands produce
be the most
prolific.
The
oil,
and the lowest

from 100
wells range in depth
to 4000 feet.
The character
of the oil found in this region
is said by Dr. Day

any other petroleum thus far found in the
free from sulphur and usually from asphalt,
to differ essentially from
world.
It is practically
PLATE XI

but
is
rich in paraffin wax.
Added
95
to this
is its easy conversion

the
lamp oil,
yields
greatest percentage,
being far ahead of all others except the Lima and Ohio petroleums,
which, however, are more expensive to refine.
into
of
which product
it
The Kentucky and Tennessee product, while inferior to that

found in Pennsylvania, is much better than the Russian or
any
other of the foreign products with which it has to compete.
Dry
!!C
oil
sand
Oil accumulation
Gas accumulation
FIG. 34.
Diagrammatic section of sands in the central Appalachian

Griswold and Munn, U. S. Geol. Sure., Bull. 318.)
region.
(After
The Appalachian region, however, has passed the zenith of its

production, that of Pennsylvania having been reached seventeen years ago; and yet some of the wells show a remarkably
though small, production.
State petroleum is obtained from the fine-grained
sandstones of Chemung age in parts of Cattaraugus, Allegany, and
Steuben counties. The wells range from 600 to 1800 feet in depth,
and while of small capacity, they yield a product of good quality,
which ranges from amber to black in color.
The petroleum-producing belt extends across Pennsylvania, in a
persistent,
In
New York
southwesterly direction, leaving it in the southwestern corner.

Within this area (whose general structure has been referred to above)
there are a number of oil pools, occurring in rocks ranging from the
Conemaugh series of the Carboniferous down to and including the

Chemung division of the Devonian. In the space permitted
here,
it is
not possible to go into detail regarding
all
the pools.
96
ECONOMIC GEOLOGY
97
ECONOMIC GEOLOGY
98
Suffice
it,
therefore, to say, that the oil
is
obtained from a
num-
ber of different sands, some of which are of high importance,

as the Berea, Hundred Foot, Fifth, etc.
Although the Appalachian

pools
are
being
discovered
field
in
is
West
on the wane, some new

Virginia
Ohio (39 and b) and Kentucky (32, 32a), but no

have been obtained in Tennessee (48a).
57),
central
definite
results
(56,
In recent years the Bremen field (396) of southeastern Ohio

has become of interest and importance, because of its yield of
from the Clinton sandstone (39a).

This formation dips
but
there
are
occasional
reversals
of dip, which
southeasterly,
local
in
which
to
develop
basins,
according
Bownocker, the oil
occurs.
The sand is dry and has a thickness of about 30 feet.
In the table given on pp. 96 and 97, an attempt has been made
to show the oil (and gas) sands known in the different formations,
oil
but they are correlated only so far as occurring in the same

formation. 1
The discovery of oil and

Ohio-Indiana Field (24-26, 39-44).
gas in the Trenton rocks of western Ohio in 1884 caused considerable excitement, since it showed the existence of petroleum in limean exception to previously known conditions, and at a much
lower geological horizon than any in which oil or gas had hitherto
been found. This field extends from Findlay in northwestern Ohio
stone,
southwestward into Indiana.
TRENTON
UTICA
LIMESTONE
SHALE
HUDSON R.
SHALE
MEDINA
NIAGARA LIMESTONE
NIAGARA SHALE
CLINTON LIMESTONE
LOWER
HELDERBERG
LIMESTONE
oil and gas

U. S. Geol. Surv., 8th Ann. Rept., II.)
Geological section of Ohio-Indiana
FIG. 35.
Most of the Trenton
oil
UPPER
HELDERBERG
LIMESTONE
fields.
OHIO
SHALE
(After Orton,
has been found in the upper 50 feet of the
formation, in one of two thin streaks; but at several localities in both

1
These tables are those given by the respective state surveys.
99
Ohio and Indiana, a productive horizon lying from 100 to 200 feet
deeper has been discovered. The oils of this field contain sufficient
sulphur to require special treatment for its elimination, but the oil
is
of paraffin base like that of the Appalachian region.

Outside of the main field, oil has been found in the Clinton for-
most important occurrence being in Vinton

oil has been obtained from the CornifCounty
erous limestone (Devonian) and from the Huron sandstone (Lower
Carboniferous) in Gibson County. The latter occurrence is exceedingly pockety, and the oil, which is darker and thicker than
the Trenton oil, has a low percentage of illuminants.
Ohio and Indiana show a much smaller production than
mation
of Ohio, the
(39)
In Indiana
formerly.
Illinois Field
in Illinois for
(23,
23a and
6)
Oil
and gas have been known
some
years, but the important discoveries were

1904, and the production since then has in-
not made until

creased at such a rapid rate that in 1913 it ranked third in
the list of producing states.
The oil fields, of which there are two the eastern and the
western, are associated with the spoon-shaped basin of the
Eastern Interior Coal Region. On the eastern slope of this
syncline is a somewhat persistent ridge, the La Salle anticline,
whose extension is traceable across southwestern Indiana to
Hartford, Ky., and it is in this arch that the sands have proved
very productive, especially in Clark, Crawford, and Lawrence
Seven sands, ranging

counties, a distance of about 66 miles.
feet in depth, are known in Lawrence County.
from 450-1985
On
the western slope there are a number of separate anticlines, which have yielded oil at a number of points from Morgan
to Jackson Counties (Fig. 35).
The principal horizons at which
oil
and gas have thus
far
been discovered are in the Carboniferous rocks, the sands occurring

in both the Upper and Lower Coal Measures, the Pottsvillo
group, and the Birdsville and Tribune of the Mississippian.
Most of the Illinois oils are above 30 B., have aparaffine
The average gasoline

essentially free from sulphur.
15 per cent.
In general the depth of the wells increases from north to
base,
and are
content
is
Oilfield pool, 300-350; Siggins pool, 400 and

Johnson
570;
township, 470 and 610; Crawford County, 900
to 1000; Lawrence County, 950, 1300, 1500.
south as follows:
ECONOMIC GEOLOGY
100
V-r-i
I
IROQUOI
FORD
(_
ILLINOIS OIL
AND GAS FIELDS

oil field
1.
Plymouth
2.
Pike County gas
3.
Jacksonville gas field
1.
Carlin ville
and gas
6.
Greenville gas
7.
Carlyle
8.
Sparta
9.
Sandoval
10.
Main
field
field*
'
MONR
field
oil field
and gas
oil
field*
oil field.
oil fields
U. Allendale
12.
and gas
oil
5. Litchfield oil
field
Stanntou
oil field
oil
and gas
field
abandoned
SCALE OF MILES
10
FIG. 36.
The
Map
of Illinois
Illinois
field
region, because the
product carries
less
20
30
10
50
showing distribution of
is
oils
oil fields.
no longer included
in the
are of different horizon.
sulphur and
much
(After
De
Wolf.)
Ohio-Indiana
Moreover, the
of it is refined without
FIG.
FIG. 2.
General view of
View
Tuna
Valley, in Pennsylvania
F. H. Oliphant.)
oil
field.
Los Angeles, Cal., oil field. Such close spacing of

tends to hasten the exhaustion of the oil supply.
in
(Photo, by
oil
derricks
(101)
ECONOMIC GEOLOGY
102
Some of it contains asphalt as well as paraffin,

within
wide limits of gravity and distillation
vary
special treatment.
and the
oils
products.
Mid-Continental Field
This region underlies

(28, 45, 45a-tf)
a portion of southeastern Kansas and northeastern Oklahoma,
and extends roughly from Paola, Kansas, to Colgate, Oklahoma.
The Pennsylvanian rocks which outcrop in this area dip westward in Kansas, and in northern Oklahoma from 50 feet per
mile, to less than 20 feet per mile, as they are followed to the
west, but in the southern part of the field they appear to be
folded into anticlines and synclines.
Three-fourths of the oil
has come from the Cherokee formation at the base of the Pennsylvanian, a little from the Fort Scott Limestone member above
it, and in the western part of the field the beds still higher in
.
the section have yielded oil.

The sands outcrop in southeastern Kansas and eastern Okla-
homa
are 300 to 800 feet deep in
near Bartlesville
Nowata County, 1200
and Tulsa, and 2700
feet in the
to 2000
Cleveland
Pool.
The sands, which are usually lenticles capped by shale and

sometimes limestone, may vary from 20 to 100 feet in thickness, and while there are usually not more than one or two in
a pool, the Glen Pool, one of the most important, contains at
least four.
Most
of the
Kansas oils are asphaltic, but in Oklahoma oils

and paraffin types are found, those from near
of both asphaltic
Muskogee resembling the Pennsylvania

This
but the output

California
oil
fields lie
oils.
the second largest producer in the United States,
field is
supplied mainly by Oklahoma.

\Vhile all the commercially productive
in the southern half of the state, along the flanks
is
(15-20).
of the Coast Ranges, they are divisible unto two groups (Fig.
37) as follows:
(1) Valley districts, including the Coalinga,
Hills, McKittrick, Midway, Sunset, and Kern River; and
coast
districts, lying on the west flank of the Coast Ranges,
(2)
Lost
and including Santa Maria, Summerland, Santa Clara Valley,

Los Angeles, Puente Hills, and others.
The
found at one or another place in every important

horizon
from the Chico of the Upper Cretaceous to the
geologic
Fernando of the Pliocene, and the structure is quite varied.
oil is
In the San Joaquin Valley districts the
oil is
generally associated
103
with monoclines, but in the coastal counties, anticlines and

faults are more effective factors of accumulation.
Sandstones
commonly form the reservoir rock, but exceptionally, as in the
Santa Maria
field,
the
oil
occurs in cracks in hard flinty shales
or in the pores of softer ones.
MAP OF
A PORTION OF
CALIFORNIA
Showing Fipe Lines aiiJ Oil
SCALE OF MILES
FIG. 37.
Map
Districts
and pipe lines. (After Arnold and

Min. Engrs., Bull. 87, 1914.)
of California oil fields
Amer.
Inst.
Garfias,
the oil sand outcrops, it is often sealed by asphalt.

Arnold believes that the oil has been derived from both animal
and vegetable matter, but chiefly diatoms.
and
Nearly all of the California oils have an asphalt base,
or
fuel
for
used
is
cent of the output
heavy oil,
about 40
Where
per
road dressing, while the remaining 60 per cent
residuum being used for fuel.
is
refined, the
ECONOMIC GEOLOGY
104
which is the most important, the well records

Miocene (Tertiary) sands and clays in which the
general westerly dip away from the Sierra granites has been locally interrupted by anticlines, on the flanks of which the oil has been found.
The oil occurs in sands interbedded with the clays which underlie one
heavy clay bed and overlie another. The thickness of the oil-bearing sands
may vary from 200 or 300 to 400 or 500 feet.
The Santa Maria field comprises the Santa Maria, Lompoc, and Cat
Canyon fields, in northern Santa Barbara and southern San Luis Obispo
County. The formations involved in the productive region range from
Lower Miocene to Quaternary, involving beds of shale, sandstone, diatomaceous earth, and volcanic ash.
The region contains long sinuous folds of a peculiar type, and most of
the wells arc located along or near anticlines, ranging in depth from 1500
In the Kern River
indicate a great
body
field,
of
North-south section, showing structure of western
FIG. 38.
district.
(After Eldridge
and Arnold, U.
field of
Los Angeles
S. Geol. Sure., Bull, 309.)
to over 4000 feet.

In the Santa Maria and Lompoc fields the oil is obtained from zones of fractured shale, or sand} layers in the lower portion
of Monterey (Middle Miocene), and has an average gravity of 25 B.
1
Although the Kern River field leads in point of production, the Santa
Maria leads in the production per well, and supplies most of the oil exported,
its situation giving it command of the coast trade from Alaska to Chile,
as well as foreign trade with Japan and Hawaii.
The Summerland
field is of interest, for
have been derived from diatoms
the reason that Arnold believes
and other organisms found

has subsequently migrated upward into the
overlying Fernando, and to some extent Pleistocene formations, urged along
probably by gas or hydrostatic pressure. A similar origin is also ascribed
to the oil in the Coalinga district.
the
in
oil
the
The
to
Monterey
shale.
(19),
It
California oils are generally characterized
by much
asphalt and
little
or no paraffin, although in recent years there has been a considerable yield

of lighter grade oils from the Santa Maria and Monterey districts.
Since
these are well adapted to refining, they will probably be in strong demand.
ECONOMIC GEOLOGY
106
Texas-Louisiana Oil Fields
(34, 35, 49-51)
series of small scattered fields lying
This
mostly
includes
in the coastal plain
region of Texas and Louisiana (PL X). Underlying the coastal

plain there is a series of Quaternary, Tertiary, and Cretaceous
clays,
and
sands,
general
gravels,
gentle
with occasional limestones, having

dip, interrupted by low
southeastern
LEGEND
SALT
FIG. 39.
DOLOMITE
Section of Spindle
Top
CLAY
SAND
El
SHALE,
GVPSUM.
oil field near Beaumont, Tex.

Min. Mag., XI.)
(After
Fenneman,
domes, which, in parts of Louisiana at least, appear to be

due to the upthrust caused by the growth of salt and gypsum
masses.
L'nder these domes, or mounds, and underlying the sediments
mentioned above, there are usually found deposits of marly or
crystalline limestone (often dolomitic), sulphur, gypsum, and
rock salt, which in most cases are at considerable depth, but
Thus at Avery Island,

occasionally lie at or near the surface.
of
rock
salt
comes within 15 feet
the
Louisiana,
heavy deposit
of the surface, but at Spindle Top, Texas, the limestone is 800
or 900 feet deep.
The
oil
is
most
frequently
found in
or
near the lime-
stones.
The oil pools are of small size, and that discovered at Beaumont, Texas, may serve as a type of many. This pool, which
covers an area of about 200 acres (PL XIII), was discovered in
1901, and within a year and a half 280 successful wells had been
drilled.
The oil rock, which lies from 900 to 1000 feet below
the
surface,
is
a very porous, crystalline, dolomitic limestone,

The occurrence of gypsum and salt
is clay.
and the cap rock

underlying the oil rock in some
of the wells is unique (Fig. 39).
Many of the wells in this pool
were gushers, but so great was the

drain on this field that by the
end of the first year after its
\
\-a
\*
\
\
discovery the pressure was considerably reduced, and in 1903
many
of the wells
had practically
ceased producing, while others

were yielding a mixture of salt
water and
however,
oil.
is
The
still
although the supply
The
exhaustible.
production,
considerable,
is
no doubt
coastal-plain
have an asphaltic base, or

"
are
heavy," and at times conoils
tain considerable sulphur.

In 1903 many wells
developed
being
Lake
district
northwest
oil
is
of
heavy
in
about
the
were
Sour
20
miles
Beaumont.
like that of
mont, but runs lower
The
Beau-
in sulphur.
In Louisiana active drilling operations have been carried on in

the region around Jennings, and
one well yielded 20,000 barrels
per day while it was gushing.
oil resembles that of Beau-
The
mont.
The
belt of Cretaceous rocks
Texas has yielded both

and gas at several localities,
but the only important one is
at Corsicana, where both a
light and heavy oil have been
found in sands interbedded with
dense clay shales. The two
of central
oil
kinds of
horizons.
oil
occur at different
II
107
ECONOMIC GEOLOGY
108
In northwestern Louisiana, both oil and gas are found in the more or
Cretaceous rocks, which underlie the Tertiary and Quaternary. Here the Cretaceous rocks which dip to the southward show a domelike uplift of considerable dimensions, which brings them within 700 feet
This includes the Caddo field, and although the oil and
of the surface.
gas occur separately or together at four horizons, viz. the Nacatoch,
less consolidated
Austin, Eagle Ford, and Woodbine, of the Upper Cretaceous, most of the
gas is obtained from the first or upper, and the oil from the fourth or lower
division.
The main
oil
field is light, similar to
sand is about 2200 feet deep.

The oil from this
that of the Appalachian region, and thus differs
strongly from the Beaumont and Jennings oils (Harris).

Most of the oils of the Gulf region contain considerable quantities of sulphur, largely in the form of hydrogen sulphide, and therefore easily removed
before refining, or for use as fuel.
They make a good fuel oil,
of the field can be easily exported, but they
also yield a good grade of lubricating oil.
Moreover, the gasolene derived
from them is acceptable as a substitute for turpentine.
by steam
which because of the location
The Corsicana and Caddo

Colorado.
oil-producing
field oils
are lighter
and run lower
in sulphur.
Florence (21) and Boulder (22) are the two important

At the former the oil is found in beds of
localities.
Cretaceous age, at depths of from 1000 to 2000

many occurrences, appears to have accumulated in
feet,
and, unlike
fissures, although
the rocks of the region as a whole form a syncline.
At Boulder, the oil is found associated with broad low anticlines in
sandstones and shales of the Pierre (Cretaceous) formation, and
now being obtained at depths ranging from 2100 to 2350 feet.

oil does not vary much in quality.
FIG. 41.
Map of Wyoming,
showing approximately the areas underlain by

gas.
(After Day.)
R. D. George, private communication.
is
The
oil
and

Wyoming
(58-63)
some gas
districts
developed.
The
109
This state contains a number of
oil and
most of which are but slightly
obtained chiefly from the Cretaceous,
(Fig. 41),
oil
is
and many
of the occurrences appear to be associated with anticlines (62), but, in one field (Spring Valley, Uinta
County)
at least (63), the oil occurs in a synclinal basin (Fig. 42), whose
bounding fault on the northwest seems to have permitted some-
what abundant seepage.

The oils vary in their
data, are mainly of
gravity, but, according to published
medium
gravity.
Sea Level
K4-2000
jTg
5 SECTION X-X
Feet
Feet
8000
8000
6000
6000
4000
4000
2000
2000
Sea Level
FIG. 42.
Sea Level
SECTION Y-Y
Section across portion of oil district of southwestern

Veatch, U. S. Geol. Sun., Prof. Pap. 56.)
Wyoming.
(After
The Salt Creek field is the most important producer, its product being piped to Casper for refining.
Alaska (14).
Oil has thus far been found in Alaska at only
four localities, at which the indications were sufficient to warrant
Wells have been driven at three, and disclosed the presence
All of the fields lie in the
similar to that of Pennsylvania.
Pacific coast region, but none have been extensively developed, as
drilling.
of
oil
the low price of imported oil and high cost of drilling in Alaska have
discouraged attempts towards development.
In the Katalla field, located near the mouth of the Copper River,
found in complexly folded and faulted Tertiary shales and

At Cook Inlet, folded and faulted Jurassic shales and
sandstones form the petroliferous horizon. At Cold Bay, where
seepages are found as in the other fields, the structural conditions
the
oil is
sandstones.
ECONOMIC GEOLOGY
110
and age
of the oil-bearing strata are similar to those at
Cook
In-
Seepages are found in Tertiary rocks near Cape Yakataga,

but no wells have been drilled.
let.
s
-*ie(;,
FIG. 43.
Map
Summary.
mode
of Alaska,
The
showing areas in which

(After Day.)
or gas are
known
to occur.
following table summarizes very briefly the
of occurrence in the several fields
SUMMARY OF OIL OCCURRENCE

FIELD
oil
IN THE PRINCIPAL
UNITED STATES FIELDS
111
In Ontario the important wells are confined to the Paleozoic

rocks of the area lying west and southwest of a line connecting
Georgian Bay and Toronto. The flat-lying undisturbed sediof this series have a thickness of nearly 3800 feet in Lambton County, but their thickness decreases as the pre-Cambrian
rocks to the north are approached. The oil occurs in the Onon-
ments
daga, Oriskany, Guelph, Niagara, Medina, and Trenton, the first

named being the most important, and supplying the oil in the
most important field. The depths to which the wells

penetrate vary on the average from about 350 to 1300 feet.
In New Brunswick oil is obtained from the Albert shales of the
Petrolia or
Subcarboniferous.
Considerable prospecting has been done recently along the

west of a line connecting Calgary and Edmonton, and
while small quantities of oil have been struck here and there
foothills
the Dakota sandstone, no large producers have been de-
in
veloped.
The Mexican oil field is located in a rectangle 50 miles wide

Mexico. 1
and 160 miles long, extending from Tampico west to Panuco and thence
south to Tuxpam. Its growth can be seen by the increase from a recorded
production of 200,000 barrels in 1904, to 25,725,403 barrels in 1914. The
main districts are Ebano, Panuco, Tuxpam, and Huasteca, the first-named
being the oldest and the last-named the most important.
The geologic formations include: (1) Tamasopa limestone (Upper (?)
Cretaceous);
San Felipe limestones and
(2)
shales
(Upper Cretaceous);
shales (Eocene); (4) Tertiary limestones, sandstones

and clays, and Pleistocene deposits of no importance in the oil occurrence;
in the form of
(5) Igneous intrusions of late Tertiary or early Quaternary,
Mendez marls and
(3)
dikes,
is
sills,
The general gentle easterly dip of the sediments

by domes and basins, the beds being also fractured by joints
The intrusive stocks show a close association with the oil,
or stocks.
interrupted
and
faults.
but the exact significance of this is not settled to the satisfaction of all,
though they doubtless by deformation of the sedimentaries may have been
an influencing factor in the oil accumulation.
The oil in general seems to come from near the top of the Tamasopa
limestones, but
it
may have
originated in the
Mendez
marls.
It is usually
with
heavy, with an asphaltic base, the thickness sometimes interfering
Some of the wells have shown an
its transportation through pipe lines.
enormous yield. One, the Juan Casiano No. 7, has been making about
to its credit, while
700,000 barrels per month, with about 40,000,000 barrels
and after proanother, the Dos Bocas gusher, blew a crater in the ground,
water.
salt
to
went
for
57
a
barrels
days,
day
ducing 200,000
1
X, No. 3, 1915; Ordonez, Amer. Inst. Min. En^rs.,

105:
Golyer, Ibid., Bull. 105: 1899, 1915; Huntley, Ibid., Bull.
Garfias, Econ. Geol.,
L: 859, 1914;
2067, 1915.
De
ECONOMIC GEOLOGY
112
HP
FIG. 44.
Sketch
roads.
Map
of the
Mexican Oil Fields, showing Pipe Lines and RailAmer. Inst. Min. Engrs., Bull. 105, 1915.)
(After Huntley,
Basalt Dike
(Hypothetical along
this lection)
FIG. 45.
terrace
Hypothetical Section through the Panuco Field, Mexico, showing anticlinal

fracture.
(After Huntley, Amer. Inst. Min. Engrs., Bull. 105, 1915.)
and
113
Other Important Foreign Fields.

Among the foreign producers, Russia
and Rumania have contributed considerably to the world's supply
In Russia, 1 the Baku region on the Apsheron pensinula
of petroleum.
of the eastern Caucasus, yields 75 per cent of the country's output.
The
Galicia
rocks involved are Pliocene, Miocene, and Oligocene sediments, with some
volcanic ash, and the whole series has been strongly folded and faulted,
mud volcanoes
and seepages being distributed along the main line of uplift.

which has a thickness of 5000 feet, consists of Miocene clays,
Of the three divisions found in the largest or Balakhanysands and marls.
Sabunchy field, the upper is productive with the wells ranging from 300
to 2400 feet in depth. Another small but productive district is the BibiEibat on the Caspian shore.
In the Galician 2 oil field on the north flanks of the Carpathians, the oil
Eocene rocks, while in the Rumanian
is obtained from strongly folded
field, which is continuous with that of Galicia, the Miocene and Pliocene
The
oil series,
formations are the petroliferous ones.

over 2 per cent of the world's output
southeastern Borneo, the
oil is
Distribution of Natural
is
The only other

the Dutch East
region producing
Indies, where, in
found in Miocene sandstones.
Gas in the United
States.
The distribu-
tion of gas is practically coextensive with that of petroleum, and

'most oil wells yield some gas; but the regions from which supplies are
obtained and utilized are fewer than those of petroleum.
Day (53) gives the following estimate of the area in square miles
of gas pools in the several fields.
290
550
Kentucky
New York
Appalachian
Ohio
Pennsylvania
West
Ohio-Indiana
Virginia
....
....
110
2730
1000
2460
Indiana
Ohio
165
2625
50
40
Illinois
Michigan
Mid-Continental
4680
Oklahoma
1000
70
550
Missouri
Kansas
1620
80
Colorado
Wyoming
310
California
Texas-Louisiana
Others
__29p
10,055
Adiassevich, Amer. Inst. Min. Engrs.,
Geol., IV:
2
89, 1909.
Dalton,
loc. cit.
XLVIII:
613, 1915;
Dalton, Econ.
ECONOMIC GEOLOGY
114
Natural gas shows a wide geologic distribution, for in the

United States and Canada it is found at one place or another
in formations ranging from Cambrian to Tertiary, exclusive of
Jurassic
and
Triassic.
UNITED STATES
The
five
most important natural gas producing regions
are:
New
York, Pennsylvania, southeastern Ohio, West Virginia, Kentucky, and Alabama; 2. Ohio
and Indiana, Trenton rock area; 3. Clinton sand area of central
(65a)
Ohio;
1.
4.
Appalachian, including
Mid-continental area;
5.
Caddo
field of
northwestern
Louisiana.
Gas is obtained in New York (74)

Appalachian Field.
from the Corniferous, Guelph, Niagara, and Trenton limeThe
stones, and from the Medina and Potsdam sandstones.
depths range from 150 to 3000 feet, with a general monoclinal
structure.
In Pennsylvania
(78)
the gas
lies
west of the Allegheny
Moun-
tains in comparatively undisturbed strata, the productive horizons

ranging from the Conemaugh to Middle Devonian. It may
occur in others lower down, but the formations productive in

lie pretty deep in Pennsylvania, the Corniferous for
New York
example, having been encountered in Washington county at a

depth of 6000 feet.
In West Virginia (56) gas is obtained in the northwestern
half of the state -at depths of from 500 to 4000 feet, associated
with anticlines and synclines as in Pennsylvania, but, owing to
the greater thickness of the formations, the

below the Speechley (Chemung) sand.
drill
has not reached
The southeastern Ohio gas field is a continuation of the West

some Devonian gas is found in northeastern
Virginia one, while
Ohio, even west of the Appalachian belt.

Kentucky has productive gas areas obtaining a supply from
the Pottsville, Berea, Devonian shales, and Trenton limestone.
The supply comes
chiefly
from the northeastern portion
of the
state.
Ohio-Indiana
Fields (67,
68,
76,
77)
Gas
is
obtained from
the Trenton limestone along the Cincinnati anticline, but the

supply is much less than formerly. Aside from this the De-
vonian shales and limestone supply some gas in southern and

western Indiana.
115
Clinton" Sand Area, Ohio (65a, 39 and 39a, under Oil).

Gas is
obtained from the Clinton sand in a belt parallel with the Cincinnati arch, and extending from western Ontario to the Ohio
River.
In southeastern Kansas (70) gas is

Mid-Continental Field.
obtained from the Carboniferous, the same as the oil, at depths
ranging from 80 to 1300 feet, while in Oklahoma the sands of
Carboniferous age are now strongly productive.

structural features were referred to under oil.
Louisiana
(65o,
73)
The Caddo
field
of
The
general
northwestern
Louisiana, located on a broad anticline known as the Sabine

Uplift, is the most important producer, although some gas is
found with the salt domes in the southern part of the state.
The product
is all
from the Cretaceous.
Not a little gas is obtained from the difnot located in the strata above mentioned, as
Other Localities.
ferent
oil fields,
in Illinois and California.

Distribution of Natural
in Ontario (79a-6) in the
and Trenton formations.
Gas
in
Canada.
Natural gas occurs
Onondaga, Guelph, Clinton, Medina

Less important occurrences are found
most important area is the Kent field
The
in the glacial drift.
of Tilbury and Romney townships,
where the gas is obtained

from the Onondaga dolomite. In New Brunswick gas has been
obtained in Albert County from Subcarboniferous rocks, at depths
ranging from 1200 to 2000 feet.
In the western provinces (79c) natural gas was developed
at Carlstadt, Alberta, as early as 1885, but the active development at Medicine Hat, Alberta, began about 1905. At this
about
locality gas is encountered in the Belly River formation at
600 feet depth, but the main supply comes from the Niobrara
in wells ranging from 1000 to 1300 feet, and having an open flow
pressure of two to three million cubic feet per 24 hours.
The second important
gas
field
of the western provinces
is
Here the gas is obtained from the

Island, Alberta.
Dakota formation at depths of about 2000 feet. The first well
driven in 1909 showed 810 pounds pressure and seven million
around
Bow
cubic feet flow.
The gas from here
is
piped to Lethbridge and
Calgary.
Gas has been found in limited quantities at a number of other
points in the Great Plains area, that from Dunmore Junction,
Suffield and Vegreville, occurring in the Niobrara formation.
ECONOMIC GEOLOGY
116
Uses
The
three most important uses are for

but
the various distillates have special
light,
lubrication;
uses.
is
as
a
local
used
Rhigolene
anaesthetic, gasoline is used as
for
and
a
resins
in making varnish and in
as
solvent
fuel,
naphtha
of Petroleum.
heat, and
oilcloth manufacture, while benzine is of value for cleaning and as a

and an adulterant of turpentine. Astral oil and min-
substitute for
eral
sperm
oil
are special grades of illuminating
Crude petroleum
oil
with high
now much used
is
flashing points.
purposes in engines, as along the Pacific coast
west, where good coal is so scarce that

are run by the use of crude oil.
many
and
for fuel
in the south-
of the locomotives
The
paraffin residue is placed on the market for medicinal purunder

the name of vaseline, petroleum ointment, and cosmoposes
It is also used as an adulterant of candy and for electrical
line.
insulation.
Uses
of Natural
Gas. 1
Natural gas
is
widely employed as a fuel
glass works, cement

For domestic purposes, such as heating, cooking, and
Its cheapness, cleanliness, and
lighting, it is also widely used.
high calorific power, and the ease with which it can be used, have
been important factors in insuring its widespread selection for
the above purposes. Some is used in the manufacture of carbon
in factories, metallurgical establishments,
plants, etc.
black.2
The term carbon black as used in the trade is applied to lampmade upon the surfaces of metal or stone, by direct impact
of flame, while lamp black is a soot deposited by the smudge process and made from oil, resin, or some other solid or liquid raw
black
material.
profitable industry now is the separation of the more volatile

grades of gasoline from natural gas issuing from oil wells. The
gas from different regions yields from
to 8 or 10 gallons of
3
gasoline per thousand feet of gas.
The former wasteful use of natural gas, and its allowed escape
from oil wells helped greatly to deplete the supply in some fields,
so that energetic measures have been taken to combat

1
2
3
this.
Johnson and Huntley, Principles of Oil and Gas Production, 1916.

U. S. Geol. Surv., Min. Res. 1913, II: 1488, 1914.
Bureau Mines, Technical Paper No. 10.
U. S. Geol. Surv., Min. Res., 1911, II: 280, 1912.
PETROLEUM, NATURAL
GAS,
OTHER HYDROCARBONS
117
SOLID AND SEMI-SOLID BITUMENS

Under
bitumens of a more or less

in the rocks, or sometimes occupying basin-shaped depressions on the surface, and (2)
bitumen of viscous character, or maltha, which is found oozing from
fissures or pores of the rocks and sometimes collecting in pools on the
this heading are included (1)
solid character
which are found
filling fissures
surface.
Both of these are usually of rather high purity, and those belonging
to the first-named group may have a rather wide geologic and geographic (Fig. 46) range.
FIG. 46.
Map
of asphalt
and bituminous rock deposits of the United

22d Ann. Kept., IX.)
States.
(After Eldridge, U. S. Geol. Surv.,
termed asphaltites by Eldridge, but

avoid
since they are not all true asphalts, it seems best perhaps to
this term.
They are most commonly found filling fissures, usually
1
in sedimentary rocks, and might perhaps be termed vein bitumens.
Those
of the first group were
There are several varieties of these, all black

Vein Bitumens.
or dark brown in color, commonly with a pitchy odor, burning
in water, but soluble to a
readily with a smoky flame, and insoluble
in
i
The anthraxolite of Ontario occurs in slate, and an asphalt vein
(Geol. Zer
porphyry has been described from near Heidelberg, Germany.
XIII: 547, 1909.)
ECONOMIC GEOLOGY
118
varying degree in ether,

cific
cally
and
mode
in their
Their speturpentine, and naphtha.

to 1.1.
They are closely related chemi-
oil of
gravity ranges from
of occurrence,
but
differ
somewhat
in their
behavior toward solvents, as well as in their
fusibility, so that their
somewhat uncertain.
The most important
identification is often
varieties are described below.

Albertite (91).
black bitumen with a brilliant luster and conehoidal
fracture, a hardness of 1 to 2, and specific gravity 1.097. It

in alcohol, and dissolves to the extent of 4 per cent in ether
is
barely soluble
and 30 per cent
in oil of turpentine.
Some American
here, but the
occurrences of vein bitumens are thought to belong

is at Albert Mines, New Bruns-
most important occurrence
(91) where a vein of albertite is found in the Subcarboniferous shales.

vein had a length of about half a mile and was followed down its steep
dip to a depth of 1500 feet. Its thickness varied from 15 feet to zero,
and branch veinlets ran off into the wall rock. It was worked for thirty
wick
The
years and proved to be one of the most profitable mineral industries of
New
Brunswick.
a coaly, lustrous, black mineral, with a hardness of 3 to
It is found at Sudbury, Ontario, fojming
veins in a black fissile slate, but has also been described from other
Anthraxolite (93)
4,
and
is
specific gravity of 1.965.
localities.
Ozokerite (98, 106), also
termed mineral wax or
native paraffin,
is
a wax-
hydrocarbon, yellow brown to green, translucent when pure, and of

greasy feel. Its specific gravity ranges from .845 to .97. It is easily soluble
in petroleum, benzine, benzole, turpentine, and carbon disulphide, but
like
more
difficultly so in ether
It is known to occur in
and ethyl alcohol.

Utah (106) where the material
is found filling
crushed Tertiary shales, sandstones, and limestones,
near Midway, Soldiers Summit, and Coulters station on the Rio Grande and
Western Railway. The conditions are not regarded as very favorable
for working.
The most important deposit of Ozokerite is in Galicia. There
it is found forming veins from a few millimeters up to several feet in thick-ness, in much-disturbed Miocene shales and sandstones.
Grahamite (97, 105, 108).
This has a hardness of 2, and a specific gravity
fissures in zones of
of 1.145.
It is pitch-black, slightly soluble in alcohol, partly so in ether,

petroleum, and benzole, but almost completely in turpentine. Carbon disulphide and chloroform dissolve it completely.
Grahamite was originally found in the Carboniferous sandstones of
Ritchie County, W. Va.
There it occurred in a deep vertical fissure 1 to 5
feet wide at the surface, and nearly a mile in length, which was opened up at
right angles to the direction of an anticlinal fold (Fig. 47)
Through this the
.
escaped upwards from an oil pool, known to occur below, and was oxidized to grahamite. The vein has long since been worked out.
Deposits of. grahamite are also known in southeastern Oklahoma, where
the material occurs in steeply pitching veins, in sandstones, and shales.
The wall rocks, which are of Ordovician to Carboniferous age, vary from
oil
ECONOMIC GEOLOGY
120
highly folded, and the grahamite shows corresponding fluctuations in

composition which are due no doubt to differences in the degree of meta-
flat to
Wuhburn
I
FIG. 47.
E /
Map
showing relation of grahamite fissure to anticlinal fold, in Ritchie

County, W. Va. (After White, Bull. Geol. Soc. Amer., X.)
morphism which the rocks have undergone. The veins are uncertain in
and with two exceptions have not warranted extensive development.
extent,
Other deposits are located in western Arkansas but the material

badly crushed and more highly metamorphosed (105).
PROXIMATE ANALYSES OF OKLAHOMA AND ARKANSAS BITUMEN
is
121
is a bitumen related possibly to gilsonite, but distinguished

behavior towards solvents, and by its elastic and sectile
It has a hardness of 2-3, and specific gravity of 1.03; is black,
Wurtzilite (97)
from
it
by
properties.
its
with pitchy luster, and petroleum-like odor. Tabbyite is regarded by some

as similar. Wurtzilite is found filling fissures in Tertiary calcareous shales
and limestones in the western part
of the Uinta Basin, Utah.
It has
been but little mined.
Lake Asphalt (103) is not found
in the United States, but occurs in
the famous pitch lake on the island
of Trinidad, off the coast of Venezuela.
The
Fig.
1,
shaped
acres
deposit PI. XIV, and PI. XV,

appears to occupy a basin-
depression
and nearly
of
about
circular
100
outline
48) lying 138 feet above the

The material evidently
arises from some source below, as
(Fig.
sea
level.
excavations
up again
made
in
in
the pitch fill

Two
time.
short
forms of the asphalt are recognized,

the lake pitch and the land
pitch, the latter being asphalt which
viz.,
has overflowed from the lake at a

low point on its rim, and run down
to the sea.
Up to the present time
FIG. 48.
Plan of Trinidad pitch

(After Peckham.)
lake.
over 3 million short tons of asphalt

have been exported from the island.
applied to a bitumen
resembling Uintaite, found on the island of Barbados.
It is a hydrocarbon of high purity, black color, brilliant
luster, and conchoidal fracture.
The Manjak is found in veins cutting obliquely
across the upper strata of the oil series (Oligocene)
and disseminated through the clays. The largest
vein is over 27 feet thick and often shows unusually
Manjak
(100 a)
rich pockets.
is
The
the
name
close association of this asphalt
with the petroleum has led most geologists to assume

its
derivation from the latter.

Uintaite, or Gilsonite (97),
is
black, brilliant
bitumen, with conchoidal fracture, hardness 2 to
2.5,
Section of
It is partly FIG. 49.
1.065 to 1.07.
Gilsonite vein, Utah.
soluble in alcohol (45.4 per cent), more so in ether, and
(After Eldridge, U. 8.
completely in chloroform and warm oil of turpentine.
Geol. Sun., 17th Ann.
and
and
specific gravity of
found filling a series of fissures (Figs. 49

Kept., I).
termed veins, in the Bridger beds of the Tertiary
to a less extent, In
of Uintah and Wasatch counties, northeastern Utah, and,
It
is
50),
ECONOMIC GEOLOGY
122
Ths veins strike usually northeast-southwest,

greatly in width, extremes of 18 feet being
reported.
They are traceable for long dis-
western Colorado.
and vary
tances, but their vertical depth appears to

be unknown.
This is usually found issuing
Maltha.
from crevices or pores of the rocks, the latter

being sometimes of bituminous character.
It can also be extracted from bituminous
rock and asphaltic oils.
Maltha is not known to occur in large
deposits in the United States, although it is
somewhat widely distributed in some of the
California oil fields, where the petroleum
exudes from the rocks, and on exposure to
the air becomes converted into maltha by
the loss of its more volatile constituents.
In the Santa Barbara (18) and Kern County
oil fields it is found in fissures of limited
extent.
Its occurrence has also been noted
in Oklahoma.
Oil asphalt is obtained from the distillation
of certain asphaltic oils of California and
Texas, and some of these are said to contain
over 35 per cent of it. 1
FIG. 50.
Gilsonite
Utah.
Dragon,
mine
The
at
cut
represents position of vein.

(Kept,
spector,
of
Coal
Mine
In-
Utah, 1905-1906.)
ELEMENTARY ANALYSES OF BITUMENS AND MALTHA
PLATE
FIG.
1.
View
XV
of portion of Trinidad asphalt lake,
(Photo, loaned by Barber Asphalt
FIG.
2.
Quarry
of
showing digging operations.

Company.)
bituminous sandstone, Santa Cruz, Cal.

U. S. Geol. Sure., 22d Ann. Kept., I.)
(After
Eldridge,
(123)
ECONOMIC GEOLOGY
124
BITUMINOUS ROCKS
Under this heading are included consolidated and unconsolidated
whose pores are more or less completely filled with bituminous
rocks,
matter, often of asphaltic character (97).

They are commonly classified according to the character of the
containing rock as bituminous sands or sandstones, bituminous
limestones, shales, or schists.
Bituminous rocks vary not only in their richness, but also in their
value for paving purposes, for while in some the bituminous matter
is purely asphalt proper, in others it may consist wholly or in part of
maltha or some liquid bitumen, which may interfere with its use for
paving purposes.
Deposits of bituminous rock are more widely distributed than the
vein bitumens, being found in several geological horizons, and are
worked in Kentucky (97a) Oklahoma (97a) and California (97)
In California deposits of asphaltic shale and sandstone are not of
rare occurrence in the oil regions from Santa Cruz southward. The
bituminous sandstone quarried near the above named place (PI. XV,
,
Fig. 2)
is
of blackish or brownish-black color, weathering to gray,
and occurs beneath the Monterey shales; it sometimes rests directly

on the granites. The bitumen impregnates the heavy-bedded sandstone immediately under the shale, and also the sand that fills
cracks which extend up into the shale. These cracks, which vary
in width from very minute size up to 25 or 30 feet, are sometimes
traceable for several hundred feet, being at times of value as guides
in finding the main bed.
ANALYSES OF BITUMINOUS ROCKS
LOCALITY
125
with a bituminous content ranging from 5 to 21 per cent, but 7

per cent is claimed to be sufficient for commercial purposes (96a)
In Oklahoma deposits have been found in a belt
extending
from the Arkansas boundary westward to the Wichita Moun.
tains.
The
material includes bituminous sandstone of Permian
and
also Pennsylvanian age, and Ordovician limestones (lOOa).

Large quantities of bituminous rock are obtained from the
Jurassic limestones of France, from Tertiary limestones of Italy,

as well as other localities in Europe. 1
OIL SHALES
Shale containing sufficient petroleum to permit its extraction
by a process of distillation is known as torbanite or kerosene
Such shales are found in the Carboniferous of

South Wales, Australia, New Zealand, and Scotland, and
in the Cretaceous of Brazil.
Those in New South Wales have
been worked, and in Scotland the industry has thrived under
shale (80-84).
New
careful
management for a number of years (83)

named country the crude oil extracted by
.
In the last
distilla-
tion from a ton of shale varies from 16 to 35 gallons, while the

ammonium sulphate ranges from 30 to 75 pounds.
Highly bituminous shale is known to occur in the Green

River (Tertiary) formation of the Uinta Basin in Colorado and
Utah (84a). It forms lenticular beds from one-half inch to 80
feet in thickness, is light to dark brown in color, and gives a
petroleum odor when struck with the hammer. The shale turns
gray on prolonged weathering.
The amount of oil obtained varied from 10.4 to 61.2 gallons,
with an average of 30.4 gallons. Much of the bituminous material
is
in the
form
oil distilled in
of liquid
the
field
oil,
semisolid and solid asphalt. The

of 26.5 to 16.0 Beaume*.
had a gravity
The occurrence
of a considerable proportion of unsaturated

carbons in these as well as the Scotch shales, may involve some
loss in refining.
In Albert and Westmoreland counties of New Brunswick,

Canada, there is a considerable area underlain by black, brown,
and gray shales of Subcarboniferous age, which contain a number of bands of oil shale. Tests of some of these have yielded
1
Dammer and
Tietze,
Die Nutzbarcn Mineralien,
II:
493, 1914.
126
ECONOMIC GEOLOGY
63 gallons of crude oil per ton, and in 1909 investigations were

under way looking towards their development (84).
The following analysis indicates the composition of an oil shale
:
127
Production of Petroleum and Natural Gas.

Petroleum has
long been known in many parts of the world because of its
Appalachian Field ) _ ., ,
,,
n T iAu- r! 1. 1 Both these fields are on the decline.
2 Indiana-Ohio F ieldi
less than 200,000 Barrels before 19C5.
3 Illinois Field.
1
P|i-oduction
4 Mid-continental Field. Production very small prior to 1896.
5 Gulf
Field. Production very blight prior to 1898.
6 California
Field. Production
under 100,000 Barrels before 1882
FIG. 51.
presence in bituminous springs or as a floating scum on the surface of pools. It was used at an early date on the walls of Babylon and Nineveh, and was obtained by the Romans from Sicily
for use in their lamps.
ECONOMIC GEOLOGY
128
In the United States petroleum was mentioned by French misand the early Pennsylvania settlers obtained
sionaries even in 1635,
Its dissmall quantities by scooping out the oil from dug wells.
covery at a greater depth on the western slope of the Alleghanies
was made during the drilling of brine wells; but its early use was
chiefly a medicinal
one until 1863, when attempts were made to
The beginning of
purify it for use as a lubricant and illuminant.
considered
to
date
from
the sinking of a
the oil industry is usually
Drake
on
Oil
well
Colonel
successful
Creek, Pennsylvania, in
by
From
this center prospectors spread out in all directions,

valuable
discoveries, until now petroleum production and
making
rank
among the leading industries of the country, the supply
refining
1860.
coming from many states.

Natural gas was discovered and
poses at Fredonia,
New
first
employed
York, in 1821.
In 1841
for
it
economic pur-
was used
in the
Kanawha
Valley as a fuel in salt furnaces, but its first extensive use began in 1872 at Fairview, Pennsylvania.
It was used
Great
in 1885 for iron smelting at
Etna Borough near Pittsburg, and
in
1886 was piped nineteen miles from Murraysville to Pittsburg.

Now natural gas is piped long distances to cities, being used as a
fuel in
many industries,
as well as for domestic heating
and
lighting.
following tables give the production of oil and gas from 1909
to 1914 inclusive. The production of oil since 1884 is shown dia-
The
grammatically in Fig. 51. Where the production has fallen below

200,000 barrels no attempt has been made to show it. This affects
only the Gulf and Mid-Continental fields.
QUANTITY AND VALUE OF PETROLEUM MARKETED IN UNITED STATES,
1909-1911
129
QUANTITY AND VALUE OF PETROLEUM MARKETED IN UNITED STATES,

1909-1914
Continued
ECONOMIC GEOLOGY
130
WORLD'S PRODUCTION OF CRUDE PETROLEUM, 1911-1914, BY

COUNTRIES
(Barrels of 42 gallons)
COUNTRY.
i

EXPORTS OF MINERAL OILS FROM UNITED STATES, 1911-1914
Kind.
131
132
ECONOMIC GEOLOGY
MARKETED PRODUCTION OF ASPHALT,
IN
SHORT TONS
1910-1914, BY VARIETIES,
Continued
133
The imports of ichthyol in 1914 amounted to 61,416 pounds,

valued at $56,415.
During the fiscal year 1914, asphalt and manufactured asphaltic
material to the value of $1,247,020 were exported from the United
States to other countries as against similar exports valued at
$1,679,411 during 1913.
REFERENCES ON PETROLEUM
1. Becker, U. S. Geol. Surv.'
ORIGIN, OCCURRENCE, AND TECHNOLOGY.
Bull. 401, 1909.
(Relation magnetic disturbances to petroleum origin.)
la. Bosworth, Geol. Mag. IX
16 and 53, 1912. 2. Clapp, Econ. Geol.,
IV: 565, 1909. (Anticlinal theory.) 2a. Campbell, Econ. Geol. VI:
26. Clapp, Can. Dept. Mines, Mines
363, 1911.
(Origin theories.)
Branch, No. 291, 1914. (Technology and exploitation.) 2c. Clapp,
Econ. Geol. V: 503, 1910, and VII: 364, 1912. (Classification.) Econ.
Geol. VI: 1, 1911.
2d. Coste, Amer.
(Oil and gas in monoclines.)
Inst. Min. Engrs., Trans., XXI: 504, 1914.
Dis(Volcanic theory.)
:
cussion of same by Hofer. 2e. Craig, Oil finding, London, 1914. 2/.
Gilpin and Bransky, U. S. Geol. Surv., Bull. 475, 1911.
(Oil diffusion
in fuller's earth.)
2g. Hager, Practical Oil Geology, New York, 1915.
2h. Harris, Science, n. s., XXV: 546, 1912.
(Oil around salt domes.)
3a.
Dalton, Econ. Geol., IV: 603, 1909.
(Origin.
Excellent.)
Coste, Amer. Inst. Min. Engrs., Trans. XXXV: 288, and Can. Min.
3.
XII. (Volcanic origin.) 4. Hofer, Das Erdol, 2d ed..

(Brunswick, Ger.) 5. Hofer, Econ. Geol. V: 564, 1910. (Origin.)
5a. Hofer, Econ. Geol. VII: 536, 1912.
(Temperatures in oil regions.)
5b. Johnson, Science, n. s., XXXV: 458, 1912, and Econ. Geol., VI:
Inst.
Jour.,
1906.
1911.
5c. Johnson,
Amer. Inst.
(Origin and accumulation.)
Min. Engrs., Bull. 98, 1915. 5d. Lucas, Science, n. s., XXXV: 961,
1912.
(Dome theory.) 6. Munn, Econ. Geol., IV: 141 and 509,
7. Newberry, Ohio State,
1909.
(Anticlinal and hydraulic theories.)
8. Orton, Geol. Soc. Amer., Bull. IX: 85, 1892.
Agric. Kept., 1859.
9. Orton, Kentucky Geol. Surv., 1894.
(Origin and accumulation.)
11. Peck10. Clarke, U. S. Geol. Surv., Bull. 616, 1916.
(Origin.)
ham, Day, Mabery, etc., Proc. Amer. Phil. Soc., XXXVI: 93. (Origin
and composition.) 12. Redwood, B., Treatise on Petroleum. (ExcelLondon. 12a. Tarr, Econ. Geol. VII: 647, 1912.
lent.)
(Magnetic
126. Thompson, Petroleum mining, New York, 1910.
declination.)
12c. Washburne, Amer. Inst. Min. Eng., Trans., L: 829, 1915.
(Capil-
808,
13. White, Geol.

lary concentrations.)
1892.
(Anticlinal theory.)
AREAL
Soc. Amer., Bull. Ill:
187,
REPORTS.
Many analyses of oil have been published in the
Mineral Resources, U. S. Geol. Survey, since 1907. Alaska: 14. MarAlso U. S. Geol. Surv., Bull.
tin, U. S. Geol. Surv., Bull. 250, 1905.
394: 190, 1909, and Brooks, Arr.er. Inst. Min. Engrs., Trans., LI:
15. Arnold and Garfias, Amer. Inst. Min.
California:
611, 1915.
15a. Arnold and Johnson, H. R., U. S. Geol.
Engrs., Bull. 87, 1914.
ECONOMIC GEOLOGY
134
Surv.,
Bull.
Econ.
Geol.,
State'
1910.
(McKittrick-Sunset field.) 156. Fcrstner,
406,
16. Watts, Bull.
VI: 138, 1911. (S. Midway field.)
Calif.
Min. Bureau, No. 3. (Central Valley.) 17. Eldridge
and Arnold, U. S. Geol. Surv., Bull. 309, 1907. (Santa Clara Valley,
Puente Hills, and Los Angeles.) 18. Arnold and Anderson, U. S.
1907.
19. Arnold,
(Santa Maria district.)
(Summer-land district.) 20. Arnold and AnderColorado: 21. Fenneman,
son, Ibid., Bull. 398, 1910.
(Coalinga.)
U. S. Geol. Surv., Bull. 260: 436, 1905 (Florence field,) and Washburne,
22. Fenneman, U.
(Florence field.)
Ibid., Bull., 381 D:
45, 1909.
Geol.
Surv.,
Bull.
322,
Ibid., Bull. 321, 1907.
S. Geol. Surv., Bull. 225:
Illinois: 23,
(Boulder field.)
383, 1904.
23a. Blatchley, 111. Geol. Surv.
Geol. Surv., Bull. 8: 273, 1907.
Bull. 16, 1910.
236. Wheeler, Amer. Inst. Min. Engrs., Trans.
(111.)
XLVIII: 533, 1915. (General.)
Indiana: 24. Blatchley, Ind. Dspt.
Bain,
111.
Geol., 22d Ann. Kept,:

(Trenton limestone field.) 25.
155, 1898.
Chapters on petroleum in other annual reports of this series. 26. Orton,
U. S. Geol. Surv., 8th Ann. Rept., II: 475, 1889. (Trenton limestone
Kansas: 27. Adams, U. S. Geol. Surv., Bull. 184, 1901. 28. Haworth,
and others, Kansas Geol. Surv., IX, 1908. (General.) 29. See also
Volumes on Mineral Resources: issued by Kansas Geol. Surv. from
1897 to 1901. 30. Schrader and Haworth, U. S. Geol. Surv., Bull.
260: 442, 1905.
(Independence quadrangle.) 31. Adams, Haworth,
and Crane, Ibid., Bull. 238, 1904.
(lola quad.)
Kentucky: 32.
Munn, U. S. Geol. Surv., Bull. 579, 1914. (Wayne and McCreary
32o. Ibid., 471:
1912.
9,
counties.)
(Campton pool), and p. 18.
Louisiana:
(Knox county.) 33. Hoeing, Ky. Geol. Surv., Bull. 1, 1904.
34. Harris, U. S. Geol. Surv.. Bull. 429, 1910.
(General.)
35. Harris,
and Hopper, La. Geol. Surv., Bull. 8, 1909. (Caddo field.)

Michigan: 36. Gordon, Mich. Geol. Surv., Ann. Rept., 1901: 269,
1902.
New York: 37. Orton, N. Y. State Mus.
(Port Huron field.)
Bull. 30, 1899.
38. Annual bulletins on mining industry, by
(General.)
N. Y. State Museum.
Ohio: 39. Bownocker, Ohio Geol. Surv.,
Perrine,
4th
39a. Bownocker, Econ. Geol. VI: 37, 1911.

Bownocker, Ohio Geol. Surv., 4th ser., Bull.
(Bremen field.) 40. Griswold, U. S. Geol. Surv., Bull. 198.
12, 1910.
(Ober(Bereagrit oil.) 40a. Hubbard, Econ. Geol., VIII: 681, 1913.
iin district.)
41. Mabery, Amer. Chem. Jour.; Dec., 1895.
(Com42. Orton, Ohio Geol. Surv., VI:
43. Orton, U. S.
60.
position.)
Geol. Surv., 8th Ann. Rept., II: 475, 1889.
(Trenton limestone field.)
44. Griswold, U. S. Geol. Surv., Bull. 198, 1902 (Cadiz quadrangle),
and Bull. 346, 1908, also Condit, U. S. Geol. Surv., Bull. 541 9, 1914
Oklahoma: 45. Gould, Econ. Geol., VII:
(Flushing quadrangle.)
Series, Bull.
1,
(Clinton sand.)
1903.
396.
45a. Hutchinson, Okla. Geol. Surv., Bull.

719, 1912.
(General.)
2: 94, 1911.
456. Buttram, Okla. Geol. Surv., Bull. 18,.
(General.)
1914.
(Gushing pool.) 45c. Gould, Econ. Geol., VIII: 768, 1913,
(Red beds.)
45d. Smith,
(Glen pool.)
45e. Taff
U.
S.
Geol.
Surv.,
Bull.
541:
34,
1914.
1905.
(Muskogee
and Shaler, U. S. Geol. Surv., Bull. 260: 441.

LT.
S.
field.
Geol.
Oregon:
45/. Washburne,
Surv.,
Bull.
1914.
590,
(N.
w.
Ore.)
Pennsylvania:
46. Carll,
135
Ann. Rept. Pa. Geol. Surv., 1885; II, 1886. 47. Reports I to I 5 of
the same survey. 48. Report Pa. Top. and Geol. Surv., 1906-1908,
App. E: 266, 1908. (General and contains further references.) 48a.
Shaw and Munn, U. S. Geol. Surv., Bull. 454, 1911. (Foxburg quad.)
Tennessee: 486. Ashley, Res. Tenn., II, No. 7, and Munn., Tenn. Geol.
Texas: 49. Adams, U. S. Geol. Surv., Bull.
Surv., Bull. 2, 1911.
1901.
184,
(General.)
50.
Fenneman, U.
S.
Geol. Surv., Bull, 282,
51. Phillips, Tex. Univ.
Min. Surv., Bull. No. 1, 1900. (Gen51a. Udden and Phillips, Univ. Tex., Bull. 246, 1912.
eral.)
(Wichita
United States: 52. See Map of Oil Fields in
and Clay counties.)
U. S. Geol. Surv., Min. Res., 1908, also analyses in this and 1907 Min.
53. Day, U. S. Geol. Surv., Bull. 394.
Res., as well as Bull. 381-D.
1909.
Utah: 54. Richardson, U. S.
(Conservation of oil supply.)
Geol. Surv., Bull. 340: 343, 1908.
54a. Woodruff, U. S. Geol. Surv.,
1906.
Bull.
471:
76,
1912.
Wash. Geol. Surv.,
I:
(San Juan
207.
field.)
(General.).
Washington: 55. Landes,

Lupton, U. S. Geol.
55a.
West Virginia: 56. White,

Surv., Bull. 581, 1914.
(Olympic penin.)
W. Va. Geol. Surv., I a: 1, 1904. (General.) 57. White, Geol. Soc.
Amer., Bull. Ill: 187, 1892. (Mannington field.)
Wyoming: 58.
Knight and Slosson, Bull. 4, Wyo. School of Mines. (General.) 59.
Bull. 3.
(Crook and Uinta Cos.) 60. Bull. 5. (Newcastle field.)
61. Jamison, Rept. State Geologist, Bull. 4, Ser. B.
(Salt Creek field.)
62. Knight, Eng. and Min. Jour., LXXII: 358, 628, 1901; and LXXIII:
63. Veatch, U. S. Geol. Surv., Prop. Pap.
(General.)
563, 1902
W. Wyo.) 63a. Woodruff, U. S. Geol. Surv., Bull.

(Lander Creek.) 636. Wegem: nn, U. S. Gecl. teurv., Bull.
471: 56, 1912.
(Powder River field.) 63c. Barnett, U. S. Geol. Surv.,
Bull. 541
49, 1914.
(Douglas field.) 63d. Bull. 581-C, 1914. (Moor56,
1907.
(S.
452: 1911.
croft field.)
Can. Dept. Mines, Mines Branch, No. 291, 1914.

Dowling, Can. Min. Inst., Bull. 35: 164, 1915. (Al1333,
berta.)
630. Huntley, Amer. Inst. Min. Engrs., Bull. 102:
1915.
(Dakota sand.) 63/i. Knight, Ont. Bur. Mines, XXIV, Pt.
63*. Malcolm, Can. Geol. Surv., Mem. 29-E and 81.
2, 1915.
(Ont.)
Canada:
63e. Clapp,
(General.)
63/.
REFERENCES ON NATURAL GAS

Amer. Inst. Min. Engrs., Trans. XIV: 428. (Geology
and Distribution in the United States.) 65. Orton, Geol. Soc. Amer.
64. Ashburner.
Bull. I:
1913.
1911.
Bull.
87.
(U.
S.)
(Rock pressure.) 65a. Clapp, Econ. Geol., VIII: 517,

Alabama: 656. Munn, Ala. Geol. Surv., Bull. 10,
(Fayette
541:
23,
field.)
1913.
Arkansas: 65c. Smith, U. S. Geol. Surv.,

California:
66.
Smith-Poteau field.)
(Ft.
Indiana:
Watts, Calif. Min. Bureau, Bull. 3. (Central Valley.)
68.
67. Phinney, U. S. Geol. Surv., llth Ann. Rept., I: 589, 1891.
Kansas:
See also Ann. Repts. Ind. Geol. and Nat. Hist. Survey.
70. Haworth, Kan.
69. Adams, U. S. Geol. Surv., Bull. 184, 1901.
71. Orton, Geol. Soc. Amer.,
Geol. Surv., IX, 1908.
(General.)
72. Volumes on Mineral Resources,
Bull. X: 99, 1899.
(lola field.)
issued by Kan. Geol. Surv., 1897-1901.
Kentucky: 72o. Munn,
ECONOMIC GEOLOGY
136
U.
Geol.
S.
Bull.
Sur.,
531,
1913.
(Menifee
field.)
726. Hoeing,
Louisiana: 73. Harris,

Ky. Geol. Surv., Bull. 1, 1904. (General.)
(Caddo field.)
Perrine, and Hopper, La. Geol. Surv., Bull. 8, 1909.
New York: 74. Orton, N. Y. State Mus., Bull. 30, 1899. (General.)
Ohio:
75. Newland, N. Y. State Mus., Bull. 93: 943.
(New York.)
77. Orton, U. S. Geol.
76. Orton, Ohio Geol. Surv., I. 3d ser.: 55.
Oklahoma: 77a. Hutchinson,
Surv., 8th Ann. Rept., II: 475, 1889.
Okla. Geo. Surv., Bull. 2: 94, 1911.
Pennsylvania: 78. Carll and
(General.)
Phillips, Ann. Rept. Pa. Geol. Surv., 1886, Pt. II., 1887.
Texas: 79. Adams, U.
Also Ref. 48
Canadar
79tr.
796.
field.)
refs.
Mickle, Ont. Bur. Mines,
Same,
Ibid.,
XXIII:
XIX,
237, 1914.
Pt. I:
149,
1910.
(Comp. Ont.
gas.)
(Kent
Also
63e and 63i, p. 135.
REFERENCES ON OIL SHALES

Amer. Inst. Min. Engrs.,
Memoirs, Dept. Mines, and Agric.
XXX:
537.
81. Carne
(Brazil.)
South Wales, Geology No. 3:
(General treatise.) 82. Baskerville, Eng. and Min. Jour., LXXXVIII.
(General and New Brunswick.) 83. Steuart, Econ. Geol.,
149, 1909.
84. Ells, Can. Min. Inst., Jour., X:
Ill:
(Scotland.)
573, 1908.
(New Brunswick, Can.); also Jour. Ming. Soc. N. S.,
204, 1908.
XV and Dept. Mines Can., Mines Branch, Bulls. Nos. 55 and 1107,
84a. Woodruff and Day, U. S. Geol. Surv., Bull.
1910.
(E. Can.)
581-A, 1914. (n. w. Colo, and n. e. Utah.)
80. Branner,
New
REFERENCES ON SOLID AND SEMISOLID BITUMENS

85. Dow, Min. Indus., X:
51, 1902.
(History of Asphalt
86. Richardson, The Modern Asphalt Pavement, 2d ed.,
Industry.)
ORIGIN.
87. Adams,
N. Y. 1908. (Wiley and Sons.) (Uses.)
GENERAL.
Inst. Min. Engrs., Trans. XXXIII:

(Origin.)
340, 1903.
Day, Eng. Record, XL: 346. 89. Eldridge, Econ. Geol., I: 437,
1906.
(Asphalt vein formation.) 90. Peckham, Amer. Phil. Soc.,
XXXVII: 108. (Genesis of bitumens.)
SPECIAL PAPERS. 91. Bai92.
(Albertite.)
ley and Ells, Geol. Surv., Canada, 1876-1877, 384.
Blake, Amer. Inst. Min. Engrs., Trans. XVIII: 563.
(Uintaite, Al93. Coleman, Ontario, Bur. Mines, 6th Ann.
bertite, and Grahamite.)
94. Bell, Amer. Inst. Min. Engrs.,
Rept., 159, 1897.
(Anthraxolite.)
Amer.
88.
XXXVIII:
Trans.
(Athabasca River, Can., tar sands.)

Min. Bureau, Bull. 16. (California.)
96. Crosby, Amer. Naturalist, XIII: 229.
96a. Crump,
(Trinidad.)
Ky. Geol. Surv., 4th ser., I. Pt. 2: 1053, 1913. (Ky. rock asphalt.)
AREAL.
836, 1907.
95. Cooper, Calif. State
97. Eldridge, U. S. Geol. Surv., 22d Ann. Rept., I: 1901.

(General
occurrence in United States, excellent.) 97a. Ells, Can. Dept. Mines,
Spec.
of
98. Gosling, Sch.

99. Gould, Okla. Geol. Surv.,
(Ozokerite.)
100. Hayes, U. S. Geol. Surv., Bull. 213: 253.
(BitulOOa. Hovey, Min. Wld., XXIX:
sandstones, Pike Co., Ark.)
Rept.,
M.
Quart,,
Bull. 1, 1908.
minous
237,
1908.
281,
1914
XVI:
(Alberta bitum. sands.)
41.
(Manjak,
Barbados.)
1006. Hutchinson,
Okla.
Geol.

Surv., Bull. 2:
LXXIII:
50.
28,
137
101. Lane, Eng. and Min. Jour.,

(Okla.)
102. Merivale, Eng. and Min. Jour.,
LXVI:
1911.
(Mich.)
103. Peckham, Pop. Sci. Mo., LVIII: 225,

(Barbados.)
790, 1898.
104. Phillips, Univ. of Tex. Min.
1901.
(Trinidad and Venezuela.)
105 Taff, U. S. Geol. Surv., Bull.

(Texas.)
106. Taff and Smith, U.
(Grahairite, s. e. Okla.)
S. Geol. Surv., Bull. 285: 369, 1906.
(Utah Ozokerite.) 106a. Robin107. Vaughan, Eng. and
son, U. S. Geol. Surv., Bull, forthcoming.
Min. Jour., LXXIII: 344. (Cuba.) 108. White, Bull. Geol. Soc.
Surv.,
380:
Bull
286,
Amer., X:
3,
1902.
1909.
(W. Va, Grahamite.)

277, 1899.
(Galicia ozokerite.)
prak. Geol., XII: 41, 1904.
109. Zuber,
Zeitschr.
CHAPTER
III
BUILDING STONES
UNDER
this
term are included
all
stones for ordinary
masonry
construction, as well as for ornamentation, roofing, and flagging.

The number of different kinds used is very great, and includes prac-
and metamorphic rocks,

but a few stand out prominently on account of their widespread
occurrence and durability.
tically all varieties of igneous, sedimentary,
The
cost of a building stone naturally exerts decided influence on

Since the ease of splitting and dressing a stone influences
its cost, the texture is also of importance.
Color is another factor
its use.
and this, together with

other considerations, sometimes gets a fashion leading to the widespread use of certain stones. This has been well illustrated in the
in determining the value of a building stone,
eastern cities of the United States, where, for many years, Connecticut brownstone was in such great demand for use in building private
More
dwellings that much inferior stone was put on the market.
recently Indiana limestone and Ohio sandstone have met the popular
fancy, and these two are now used in vast quantities.
Properties of Building
Stones
(1-10).
The
following
prop-
have an important bearing on the value of a building stone:

Color.
The color of rocks varies greatly, and those shown by
erties
common
and
building stones include white, black, brown, red, yellow,

The color may
buff, while some are green, blue, or mottled.
vary in the same quarry.

In igneous rocks the color may be that of the prevailing mineral, as
in pink granite, where there is an excess of pink feldspar; or it may be
a composite due to the blending of the colors of several minerals, as in
the case of ordinary gray granite, where the color results from the mixture of black mica and whitish quartz and feldspar.
Sedimentary rocks
commonly owe their color to ferruginous cements, or to carbonaceous
matter. The former give brown, yellow, red, or green colors depending on
the condition of oxidation and form of combination of the iron, while the
and bluish tints depending on the amount

Sandstone and limestone free from either of these coloring agents
are nearly if not quite white.
latter produces gray, black,
present.
Only the more important ones are here considered.
sions will be found in Refs. 2, 9, 30, 41, 43a, 51.
138
Excellent detailed discus-
BUILDING STONES
139
Some stones change color on exposure to the air. For example, limestones or sandstones containing carbonaceous matter
may bleach; some
black marbles fade to a white or gray; and some red and
green roofing
slates, as well as a few red granites, change color.
Oxidation of evenly
distributed pyrite may change gray or bluish-gray sandstones to buff color.
If the minerals responsible for such change in color are not
uniformly
distributed, the stone
assumes a blotchy appearance, but such changes are
not necessarily an indication of deterioration.
FIG. 52.
Photomicrograph of a section of Granite.

A. B. Cushman.)
(Photo loaned by
Texture.
Building stones vary in their texture from coarsegrained granites and conglomerates to fine-grained sandstones, limestones,
and porphyries.
an important property, for it influences both the duracost of stone.

Other things being equal, a fine-grained
rock is not only more durable, but splits better and dresses more evenly,
than a coarse-grained rock. Uneven texture, whether due to mineral
grains or cement, is undesirable, since it often causes uneven weathering.
Texture
bility
is
and the
Density.
On
the whole, dense stones resist weather better

is great difference in the density of
than porous ones, but there

building stones.
ECONOMIC GEOLOGY
140
In general, though with some exceptions, igneous and metamorphie

rocks have high density because of the close interlocking of the crystalline grains.
Sedimentary rocks of clastic origin, on the other hand, have
less closely fitting grains, and unless the latter are very small, or the pores
well filled with cement, they are apt to be porous.
The specific gravity of a stone indicates its density; and from the
specific gravity the weight per cubic foot may often be approximately
estimated by multiplying it by 62.5, the weight of an equal volume of
water. While sufficiently accurate for very dense stones, this method is
to lead to incorrect results when applied to very porous rocks.
Following are some average specific gravities of common building stones,
as given by Hirschwald (1): granite, 2.65; syenite, 2.80; diabase, 2.80;
liable
gabbro, 2.95; serpentine, 2.60; gneiss,

2.80; sandstone, 2.10; slate, 2.70.
2.65;
limestone,
Photomicrograph of a section of Diabase.

A. B. Cushman.)
FIG. 53.
2.60;
dolomite,
(Photo loaned by
Hardness.
The hardness of a building stone is not necessarily
dependent on the hardness of its component minerals, but is largely
influenced
by
their state of aggregation,
and to some extent
their
hardness.
For example, a sandstone composed of quartz grains, but with h'ttle

cementing material, may be so soft as to crumble easily in the fingers;
while a limestone, whose grains of soft carbonate of lime fit closely and
BUILDING STONES
141
are firmly cemented, may be difficult to break with a hammer.

The
nature of the cement in sedimentary rocks, that is, whether it is lime,
silica, or iron, will also affect the hardness of the stone.
Crystalline rocks
owe their great hardness to the firm interlocking of the mineral grains.
Ths abrasive resistanse (10) of a stone will depend in part on the state of
aggregation of the mineral particles, and in part on the hardness of the
Same stones wear very unevenly because of their
grains themselves.
irregularity of hardness, and such may be less desirable than one which is
uniformly soft.
No standard form of abrasion test exists, and yet one should be applied
to thosa stones which are used for paving, steps, or flooring, as well as to
those placed in situations where they may be subjected to the attacks of
wind-blown sand, or the rubbing action of running water.
Two kinds of strength, compressive and transverse,

in building stones.
be
considered
are to
Strength.
The compressive or crushing strength, which is expressed in pounds

per square inch, is the resistance which the rock offers to a crushing
force, and is dependent chieHy on the size of the grains, state of aggregaBecause of the close interlocking of the
tion, and mineral composition.
grains of igneous rocks they are stronger than those of sedimentary origin,
in which the strength is due chiefly to the cement which binds the grains
together.
Sedimentary rosks show greatest strength when dry, or when
pressure is applied at right angles to the bedding.
Few building stones whsn in use are subjected to pressures even approximately equal to their crushing strength. No domestic building stone at
present used in the eastern market has a crushing strength of less than 6000
pounds, yet the pressure even in the tallest buildings does not require
a stone with a crushing strength exceeding 314.6 pounds, and this includes
the factor of safety of twenty usually allowed by architects. Computations show that a stone at the base of the Washington monument sustains
a maximum pressure of 6232 paunds per square inch, which includes the
usual factor of safety of twenty; the crushing strength of the stone used
in the base of the
pounds per square
monument
however not
is
less
than 10,000 to 12,000
inch.
The crushing
strength of some soft 'limestones or sandstones may be

above 3000 pounds per square inch, while that of diabase often
exceeds 30,000 pounds per square inch. The accompanying table gives
the crushing strength of a number of stones. (Many others are given in the
but
little
state reports.)
CRUSHING STRENGTH OP BUILDING STONES
Me
Granite, Vinal Haven,

Granite, East Saint Cloud,
13,381
Minn
Granite, Port Deposit, Md

Dolomite marble, Tuckahoe,
Limestone, Caen, France
Sandstone, Portland, Conn

Sandstone, E. Long Meadow,
N.Y
Mass
28,000
19,750
13,076
3,550
13,310
8,812:
ECONOMIC GEOLOGY
142
Wide
variations sometimes exist in stones from different parts of the

in stones from the same locality tested at different times.
published crushing tests of different stones cannot really be fairly
same quarry, or
The
compared because
all
have not been tested under exactly the same condi-
tions.
Transverse Strength.
The
transverse strength
is
the load which a
bar of stone, supported at both ends, is able to withstand without breakIt is measured in terms of the modulus of rupture, which represents
ing.
the force necessary to break a bar of one square inch cross section, rest-"
ing on supports one inch apart, the load being applied in the middle.
FIG. 54.
Photomicrograph of a section of quartzitic sandstone.

(Photo loaned by A. B. Cushman.)
Although stones in buildings are rarely, if ever, crushed, they are frequently
broken transversely, and therefore a knowledge of the transverse strength
is of more importance than the crushing strength.
A high crushing strength
does not necessarily mean a high transverse strength. Unfortunately
few stones have been tested in this manner.
The porosity of building

Porosity and Ratio of Absorption.
stones varies widely.
Most igneous rocks have little pore space
and hence absorb
little water;
but sedimentary rocks, especially
sandstones, are often very porous.
Many
rocks, especially those of the sedimentary class, contain water

when first quarried. This is known to quarrymen as quarry
in their pores
BUILDING STONES
143
water, and it is present in some porous sandstones in sufficient quantities

to interfere with quarrying during freezing weather.
Mineral matter in
solution in the quarry water is deposited between the grains when the water
evaporates, often in sufficient quantities to perceptibly harden the stone.
Water is also present in the joint planes, and by its passage along these
planes causes oxidation and rusting of the iron of the rock-forming minerals.
This discolors the stone along and on either side of the joint planes, giving
a yellow color known as sap.
rise to
Resistance
to Frost.
Building stones show a varying degree of
resistance to frost.
Dense rocks, like granites, quartzites, and many limestones, and even
some very porous rocks, are little affected; but many porous and laminated rocks, like open sandstones and schists, disintegrate under frost
This is due to the fact that moisture absorbed in the warmer
action.
weather, on freezing in the pores, expands, and either forces off small
Since clay readily absorbs water, clayey
pieces or disrupts the stones.
rocks are sometimes similarly affected.
Resistance
to
Heat.
All rocks
expand when heated, and con-
cooled, but do not shrink down to their original dimenThis permanent increase in size is termed permanent swellsions.
ing, and though small when figured for one linear foot, is appreciable
tract
when
in long pieces.
The following figures give the average of a number of tests of permanent

swelling in stone bars 20 inches long, heated from 32 F. to 212 F., and
then cooled to the original temperature: granite, .009 inch; marble,
.009 inch; limestone and dolomites, .007 inch; sandstone, .0047.
The most
ture
is
severe test of a stone's resistance to rapid changes of temperaC. and then immerse it in cold water.
it to about 800
to heat
Quartzites and hard sandstones withstand such treatment best; some grancrack and crumble, and the carbonate rocks change to lime.
ites
Chemical Composition.
Many chemical analyses of building
stones have been made, but most of them are of little value, largely
because they tell us nothing regarding the physical properties of the
stone.
They are perhaps of most value in the case of sedimentary
The chemical analysis of a limestone will indicate whether

dolomitic or not, also whether it is clayey in its character. So
too the analysis of a sandstone will indicate whether it is siliceous
rocks.
it is
or clayey.
This may be considered as the period

Life of a Building Stone.
of time a stone will stand exposure to the weather without showing
Even for the same stone, it may vary with location
signs of decay.
ECONOMIC GEOLOGY
144
and
Julien
climate.
tions
made on
makes the following deductions from observa-
stones in use
Coarse brownstone
Fine-laminated brownstone
Coarse fossiliferous limestone
Coarse dolomitic marble
Fine-grained marble
Granite
5-15 years
20-50 years
Quartzite
20^0
years
40
50-100
75-200
75-200
years
years
years
years
All rocks are traversed by

Structural Features affecting Quarrying.
In sedimentary rocks these
planes of separation of one sort or another.
consist of bedding and joint planes; in igneous rocks, the latter alone
are present; and in metamorphic rocks, joint planes, a banding of minerals
and, very often, cleavage planes.

These may be
(PL XVII, and PI. XXII, Fig. 1.)
Bedding planes.
either an advantage or a disadvantage to the quarryman.
They are desirable because they facilitate the extraction of the stone; but if numerous
and closely spaced, the layers may be too thin for any purpose except
flagging. They often serve as a means of entrance for the agents of weather-
and the stone

elsewhere fresh.
ing,
may
be disintegrated along the bedding planes while
Incipient planes of weakness, due either to the arrangement of minerals

or to microscopic fractures in them, often give rise to planes of easy splitting
which are of great value in quarrying, notably of granite. The most promi-
nent plane is called rift; and a less prominent vertical plane, approximately at right angles to the rift, is called the grain. Granites often
show a sheeted (PL XVI, Fig. 1) structure, due to the presence of horizontal
These are slightly curved, and hence tend to separate the granite
joints.
mass into a series of lenses.
The position of the beds exerts an important influence on the cost
When
of quarrying.
horizontal
and
of different quality,
it
may
often
be necessary to
quality.
strip off worthless rock in order to reach the beds of good

In such cases, there is often less stripping to do in quarries opened
on gently sloping ground. In regions of steep dip, it is sometimes possible

to work the quarry as a cut, extracting the desired beds and leaving useless
ones standing.
GRANITES
Characteristics of Granites
(9,
43 a).
As commonly used by
quarrymen, the term granite includes all igneous rocks and gneiss;
but in this book it is used in the geological sense, which is more
From
the geological standpoint a granite is a holocrystalline, plutonic igneous rock consisting of quartz, orthoclase feldspar, and either mica or hornblende, or both. There are also varying
restricted.
but usually small quantities of other feldspars, and there
may
be
PLATE XVI
FIG.
1.
Granite quarry, Hardwick, Vt.
FIG.
2.
Quarry
(Photo, by G.
H. Perkins.)
in volcanic tuff, north of Phoenix, Ariz.
(145)
146
ECONOMIC GEOLOGY
subordinate accessory minerals, such as pyrite, garnet, tourmaline,
and epidote.
Granites vary
in texture from fine to coarse grained, and in some

cases are porphyritic.
They pass into gneisses by such insensible
no
that
sharp line can be drawn between the two. In
gradations
color they vary, being, most commonly, gray, mottled gray, red,
pink, white, or green, according to the color or abundance of the
component minerals.
Most
granites are
permanent
in their color,
but some of bright red color bleach on continuous exposure to sunlight.
The average specific gravity of granites is 2.65, which corresponds to a

weight of 165.6 pounds per cubic foot. They commonly contain less than
1 per cent of water, and often absorb two or three tenths more.
Their
crushing strength varies, but is apt to lie between 15,000 and 30,000 pounds
per square inch.
Granites are among the most durable of building stones, but there is some
Other things being
variation in the durability of the different kinds.
equal, fine-grained granites are more durable than coarse-grained, being less
One of the most beautiful
easily affected by changes of temperature.
known, the Rapikivi granite of Finland, lacks in durability on this

Pyrite and marcasite are injurious minerals, since they rust rapVery few granites
idly and may discolor the stone in an unsightly manner.
now in use show signs of decay; but in those that do, the darker silicates
are rusted, the luster of the feldspar is dulled, and, in some cases, the stone
granites
account.
has begun to disintegrate.
Distribution of Granites in the United States
(9).
Granite
usually occurs in batholytic masses sometimes forming the cores of

mountain chains. Removal of the overlying strata by denudation
has revealed the granite, which, owing to its greater durability, is

left standing as peaks or domes by the farther removal of the
often
surrounding, weaker strata. Granites show a wide geologic range,

but most known occurrences are associated with the older formations.
Granite forms an important source of durable building stone

widely distributed in the United States (Fig. 55) but nearly 70 per
cent of that quarried comes from the Atlantic states.
There are
;
several areas which will be briefly considered.

Eastern Crystalline Belt (2, 11, 19, 26, 31, 44, 45).
From northeastern Maine southwestward to eastern Alabama there is an im-
portant belt of granites and gneisses, mostly of pre-Cambrian age.

Those at the northeastern end of the belt, as far south as New
York, are most extensively quarried, largely because of their pecul-
BUILDING STONES
iarly favorable location.
147
In this belt those of Quincy, Massachu-
Vermont (44), and Westerly, Rhode Island (41),

are of value for monumental work.
Many large quarries have also
been opened up in Maine (25a) ,but their output is employed mainly
setts (28), Barre,
A gneissic granite quarried at Port Deposit,

a white granite from Mt. Airy, North Carolina (36),
as well as a pinkish granite worked at Stone Mountain, Georgia (20),
for structural work.
Maryland
(26),
are also of some importance. Another important granite area

located near Richmond, Virginia. (46).
is
Map showing distribution of crystalline rocks (mainly granites) in

United States. (After Merrill, Stones for Building and Decoration.)
FIG. 55.
Minnesota-Wisconsin Area
areas in these two states,
some
There are several detached

which supply granites of value for
(51).
of
That from Montello, Wisconsin, bears a high

and Ortonville,
reputation, and those from Wausau, Wisconsin,
Minnesota, are favorably known.
ornamental work.
This includes portions of Missouri, ArkanSouthwestern Area.

sas, Oklahoma, and Texas.
These four states contain small areas, worked mainly to supply a
Those of southeastern Missouri vary from light gray

Some of
to red in color and fine grained to porphyritic in texture.
is important
Fredericktown
around
The
the rock is rhyolite.
region
the Arbuckle and
Important granite deposits are known in
(30).
thus
their
but
Oklahoma
development
of
(38),
Wichita Mountains
local
demand.
ECONOMIC GEOLOGY
148
far has been slight.

Arkansas contains quarries of syenite west of
Little Rock (2), and for purposes of convenience it is mentioned
under granite. In Texas quarries have been opened in Llano

County, and yield both pink and gray granite (2, 43a).
There are many areas of true granite, and
Western States.
as grano-diorite and rhyolite in the western
allied
rocks
such
closely
states.
The central portion of the Black Hills of South Dakota is
a great granite mass, but little of it is quarried. Granites are known
in Colorado (17), and quarried to some extent, and the rhyolites of
In California the
Castle Rock are of considerable importance.
mass forming the central portion of the Sierra Nevada

yields an inexhaustible supply, which is quarried at
several points.
Montana, Washington (48), and Oregon also contain granites which are quarried for local use.
On the whole, however, the Cordilleran granite industry is somewhat restricted because of lack of demand.
Uses of Granite.
On account of its massive character and
grano-diorite
Mountains
durability, granite
tion, while
some
is
much employed
for
of the granites that take
massive masonry construcand preserve a high polish,
and are susceptible of being carved, are in great demand for ornamental and monumental work. Because of its greater durability,
granite has in recent years largely replaced marble for monumental
purposes.
The refuse of the quarries is often dressed for paving blocks or
crushed for roads and railroad ballast. The size of the blocks
which can be extracted from a granite quarry depends in part on the

spacing of the joint planes, in part on the perfection of development
of the rift, some of the monoliths that have been quarried being of
immense size: for example, one from Stony Creek, Connecticut,
measured 41 ft. X 6 ft. X 6 ft.; one from Vinal Haven, Maine, 60 ft.
X 5% ft. one from Barre, Vermont, 60 ft. X 7 ft. X 6 ft.
Miscellaneous Igneous Rocks (9).
But little space need be
given to these, for they are of minor importance as compared with
;
In the eastern states the diabase or trap rock is

quarried at several points in Connecticut, New York, New Jersey,
and Pennsylvania. Owing to its great hardness it is only occasion-
the granites.
ally
used for dimension blocks,
blocks and road metal.
The
its chief
value being for paving
basaltic rocks of the western states,
especially those of Washington and California, are often employed

Anorthosites and gabbros, some of the former
for similar purposes.
being of highly ornamental character
when
polished, occur in the
BUILDING STONES
149
Adirondack Mountains, New York; they are, however, but little

utilized.
Gabbros have been quarried for local use in Maryland and
Minnesota, and diorites have been quarried to a small extent at
Some of the porphyries and rhyolites of the
scattered localities.
Atlantic states
possess considerable beauty
handsome porphyry
when
polished.
quarried in Wisconsin (51), and in the Cordilleran region both rhyolite and porphyry occur in numerous loAndesite tuffs are quarried in Colorado, and consolidated
calities.
is
volcanic tuffs have also been used to
some extent
for building in
Arizona.
LIMESTONES AND MARBLES

General Characteristics
and metamorphic
rocks,
(l,
9).
composed
great series of sedimentary
chiefly of carbonate of lime, or,
in the case of dolomite, of carbonate of lime and magnesia, is included

under the term limestone and marble. These rocks also contain
varying, but usually small, amounts of iron oxide, iron carbonate,

When of metamorphic
silica, clay, and carbonaceous matter.
character various silicates, such as mica, hornblende, and pyroxene,
may be present.
These calcareous rocks vary in texture from fine-grained, earthy,
to coarse-textured, fossiliferous rocks, and from finely crystalline to
There is, also, great range in color,
coarsely crystalline varieties.
the most common being blue, gray, white, and black, but beautiful
shades of yellow, red, pink, and green, usually due to iron oxides,
Their crushing strength commonly ranges from
are also found.
etc.,
10,000 to 15,000 pounds per square inch, while their absorption
is
generally low.
The mineral composition

its durability.
of limestone exerts a strong influence
Those limestones which are composed
on
chiefly or
containwholly of carbonate of lime are liable to solution in waters

coarsedolomite
but
carbon
limestones,
especially
dioxide;
ing
Streaks of
than
rather
decompose.
disintegrate
ones,
grained
mineral impurities cause the stone to weather unevenly. Pyrite
of its
is an especially injurious constituent, not only on account
set free by its decomporusting, but also because the sulphuric acid
sition attacks the stone.
Tremolite, which is found in some dolo-
mitic marbles, is also liable to cause trouble by its decay.

gray limestones will sometimes bleach on exposure.
Black or
In the geological sense limestones are of

Varieties of Limestones.
character, but in the
origin, while marbles are of metamorphic
sedimentary
ECONOMIC GEOLOGY
150
trade the term marble is applied to any calcareous rock capable of taking a
In addition to the different varieties of marble and the ordinary
limestones, there are certain kinds of calcareous rock to which special
polish.
names
are given, as follows

is a fine, white, earthy limestone,
:
Chalk
remains.
composed
chiefly of foraminiferal
Coquina is a loosely cemented shell aggregate, like that found near St.
Augustine, Florida.
Dolomite, or dolomitic limestone, composed of carbonate of lime and
magnesia, and to the eye alone often is indistinguishable from limestone.
Fossiliferous limestones is a general term applied to those limestones
which contain many fossil remains. Under this heading are included crinoidal limestone and coral-shell marble.
Hydraulic limestone, an argillaceous limestone containing over 10 per
cent of clayey impurities. Used mainly for cement manufacture (p. 188;.
Lithographic limestone is an exceedingly fine grained, crystalline limestone,
of gray or yellowish hue. It is used for lithographic and not structural work.
Oolitic limestone,
composed
of small,
rounded grains
of concretionary
character.
Stalactitic and stalagmitic deposits, formed on the roofs and floors of
caves, respectively, are often of crystalline texture and beautifully colored,
and, when of sufficient solidity, are known as onyx marble.
Travertine, or calcareous tufa, a limestone deposited
Roman deposits are sufficiently hard for building purposes,

in the
United States, as in Virginia, are not
so,
from springs. The

but those occurring
even though the deposits
are large.
Distribution of Limestones in the United States.

are found in
many
states,
and
in
all
Limestones
geological formations from
to Tertiary, but those of the Paleozoic, which are much

used in the eastern and central states, are more extensive and more
Cambrian
massive than those of later formations. Although many large

quarries have been opened to supply a local demand, the product is
shipped to a distance from only a few localities. At present the
Subcarboniferous
XVII)
Bedford
(22) oolitic
limestone of Indiana (PL
perhaps, the most widely used limestone in the United

It occurs in massive beds from 20 to 70 feet thick, and is
is,
States.
more than 70 square miles. Although

good strength, and has been used in
many important cities of the United States. The same rock is
quarried at Bowling Green, Ky. (23c).
In the eastern and central states the Paleozoic limestones are
said to underlie
soft
and
an area
of
easily dressed, it has
w orked
at many points, mainly to supply a local demand (3).

Cretaceous limestones are worked in Kansas, Nebraska, and
Iowa, although the most important sources are in the Paleozoic
r
formations.
ECONOMIC GEOLOGY
152
Distribution of Marbles in the United States
(2).
While some
variegated marbles are produced in the United States, still most of

those quarried are white, the greater part of the variegated stones
FIG. 56.
Map
showing marble areas of eastern United States.

tStones for Building and Decoration.)
(After Merrill,
The main supply comes chiefly from regions of

metamorphic rock, the eastern crystalline belt being the principal
being imported.
Vermont (44, 45) leads all other states in

producer (Fig. 56)
marble production, supplying a large per cent of all the marbles
.
BUILDING STONES
153
used for ornamental work in the country. The most

important and
largest quarries are those at Proctor (PI. XVIII) and West Rutland.
At the latter locality the marble bed has a thickness of 150 feet at
the top of the quarry, narrowing to 75 feet at the
bottom, and
divisible into a series of
quality,
and
is
well-marked layers of varying thickness,
color (45).
The Vermont marbles
usually show a bluish-gray or whitish

ground, the latter often showing a pinkish or creamy shade, and
traversed by veins or markings of a green or brown color.
A beautifully colored series of variegated marbles is quarried at
Swanton, Vt. (45), and much used throughout the United States
l
and wainscoting. Owing to their highly siliceous charshow excellent wearing qualities. White marbles for
structural work are quarried at Lee, Massachusetts (2), and at
South Dover and Gouverneur, New York (2, 35), but gray ones
for flooring
acter they
are also obtained from the last-named locality.
In Maryland
important quarries have been opened up at Cockeysville (26).
Large quantites of white and also gray marble are quarried in
Pickens County, Georgia (19) (PI. XIX, Fig. 1).
The Trenton limestone in eastern Tennessee (9) supplies marble
of gray, and of pinkish chocolate color with white variegation.
The Napoleon gray from
It is used chiefly for interior decoration.
Phenix, Missouri, is very similar to the Knoxville, Tenn., gray.
Marble has been reported from various other states west of
the Mississippi, but as yet little quarrying has been done. A
large deposit of white marble is said to occur at Marble, Colorado,
and that quarried in Inyo County, California, has attracted con-
siderable attention in recent years (16).
Most
of the variegated marble used for interior decoration in this counobtained from foreign countries, especially France, Belgium, Greece,
etc.
Many of these imported stones are of rare beauty, but are usually
unfitted for exterior use in severe climates, a fact often ignored by architects.
Although ornamental stones of this class occur in the United States, up to
the present time few attempts have been made to place them on the market.
This may be due to the fact that most quarrymen do not care to assume the
temporary expense which their introduction might involve.
Under this term are included two types of
Onyx Marbles (53-56).
calcareous rock, one a hot-spring deposit, or travertine, formed at the
surface, the other a cold-water deposit formed in limestone caves in the
try
is
same manner as stalagmites and stalactites. Cave onyx

crystalline and less translucent than travertine onyx.
1
is
more coarsely
The
beautiful
These should perhaps be more properly classed as calcareous sandstones.
ECONOMIC GEOLOGY
154
banding of onyx
is
due to the deposition of successive layers of carbonate

and veinings are caused by the presence
of lime, while the colored cloudings

of metallic oxides, especially iron.
Neither variety of onyx occurs in extensive beds, though both are widely
Onyx is found in Arizona, California, and Colorado, but it
has not been developed in any of these states except on a small scale.
Most of the onyx used in the United States is obtained from Mexico, though
small quantities are obtained from Egypt and north Algeria.
The value of onyx varies considerably, the poorer grades selling for
as little as 50 cents per cubic foot, while the higher grades bring $50 or more.
The earliest-worked deposits were probably those of Egypt, which were used
by the ancients for the manufacture of ornamental articles and religious
vessels; and the Romans obtained onyx from the quarries of northern AlMany of the travertine onyx deposits occur in regions of recent volgeria.
canic activity, and all of the known occurrences are of recent geological age.
distributed.
Limestones and Marbles.

The limestones are used
dimension
mainly
blocks, though some, as the Bedford
lend
well
themselves
for
carved work. The refuse from the
stone,
be
of
value
for
road
quarry may
material, lime, or Portland cement
manufacture. (See reference under Cement.)
Marbles are used in increasing quantities for ordinary structural
work, although many of the lighter-colored ones soon become soiled
by dust and smoke. The output of many quarries, especially the
Vermont ones, is well adapted to monumental purposes, and these,
together with those from Georgia, Tennessee, and California, are
much used for wainscoting and paneling. That from Swanton is
also well adapted to flooring.
Electrical switchboards are now
frequently made of marble. The demand for marble tops for
The
tables, washbasins, and similar uses is probably decreasing.
refuse from marble quarries is sometimes utilized for the same purposes as limestone. Special tests are applied to marbles (45a).
Uses
of
for ordinary
SERPENTINE
Pure serpentine is a hydrous silicate of magnesia; but beds of serpentine
are rarely pure, usually containing varying quantities of such impurities
as iron oxides, pyrite, hornblende, and carbonates of lime and magnesia.
The purer varieties are green or greenish yellow, while the impure types are
various shades of black, red, or brown.
Spotted green and white varieties
are called ophiolite or ophicalcite.
Serpentine is sometimes found in sufficiently massive form for use in
structural or decorative work; but, owing to the frequent and irregular
joints found in nearly all serpentine quarries, it is difficult to obtain other
than small-sized slabs. Its softness and beautiful color have led to its
extensive use for interior decoration; but since
it is not adapted to exterior work.
loses luster,
it
weathers irregularly and
Marble quarry, Proctor, Vt. The banding of the rock is vertical

PLATE XVIII.
benches.
The horizontal lines are caused by the stone being quarried in
(Photo.,
Vermont Marble Co.)

(155)
ECONOMIC GEOLOGY
156
Though found in a number of states, most of the numerous attempts

quarry American serpentine have been unsuccessful. Considerable
serpentine for ordinary structural work has been quarried in Chester
County, Pennsylvania, and a variety known as verdolite has been worked
to
near Easton, Pennsylvania

carried
on
in the state of
Quarrying operations have also been,

(48), Maryland and Georgia.
(32).
Washington
SANDSTONES
General Properties
While most sandstones are com-
(1, 9).
posed chiefly of quartz grains, some varieties contain an abundance

of other minerals, such as mica, or, more rarely, feldspar, which in
rare cases may even form the predominating mineral.
Pyrite is
occasionally present, and varying amounts of clay frequently occur
between the grains, at times in sufficient quantity to materially
influence the hardness and dressing qualities of the stone.
The
hardness of sandstones, however, usually depends on the amount

and character of the cement, varying from those having so small
an amount of
silica or iron
oxide cement that the stone crumbles in
the fingers to those quartzites whose grains are so firmly bound by

silica that the rock resembles solid quartz.
With these differences
the chemical composition varies from nearly pure silica to sandstone

with a large percentage of other compounds.
(For analyses, see
Kemp's
"
Handbook
There are
brown,
many
of Rocks.")
colors
among
buff, bluish gray, red,
sandstones, but light gray, white,
and yellow are most common.
In
density sandstones range from the nearly impervious quartzites to

the porous sandrocks of recent geologic formations, and consequently they show a variable absorption. Most sandstones con-
some quarry water, and those with appreciable amounts are

and more easy to dress when first quarried; but they cannot
be quarried in freezing weather. The average specific gravity of
sandstone is 2.7, and accordingly a cubic foot weighs about 160 to
tain
softer
170 pounds.
On the whole, sandstones resist heat well and are usually of excellent durability, since they contain few minerals that decompose
When
they disintegrate, it is commonly by frost action.

minerals
are pyrite, mica, and clay.
injurious
Pyrite is likely
to cause discoloration on weathering; the presence of much mica
easily.
The
off if set on edge

and clay may cause
the
in
of its capacity
to
stone
account
weather
on
injury
freezing
for absorbing moisture.
of
clay, however, makes
slight quantity
may
cause the stone to scale
PLATE
FIG.
1.
XIX
Marble quarry, Pickens County, Ga.
FIG. 2.
(Photo, loaned by S.
Slate quarry at Penrhyii, Pa.
W.
McCallie.)
(H.
(157)
ECONOMIC GEOLOGY
158
the stone easier to dress.

lessened
by
The value
careless quarrying, or
of a sandstone
by placing
it
is
often
on edge in the
building, thus exposing the bedding planes to the entrance of water.

With an increase in the size of their
Varieties of Sandstone.
grains, sandstones pass into conglomerates on the one hand and
with an increase in clay into shales. By an increase in the percentage of carbonate of lime they may also grade into limestones.
On
account of these variations, as well as the difference in color and
the character of the cement, a number of varieties of sandstone are recognized, of which the following are of economic value: arkose, a sandstone
composed chiefly of feldspar grains; blue-stone, a flagstone much quarried

New York; brownsione, a term formerly applied to sandstones of brown,
color, obtained from the eastern Triassic belt, and since stones of other
colors are now found in the same formation, the term has come to have
a geographic meaning and no longer refers to any specific physical character;
in
flagstone, a thinly bedded, argillaceous sandstone used chiefly for paving

purposes; freestone, a sandstone which splits freely and dresses easily.
Distribution of Sandstones in the United States.
Sandstones
formations from pre-Cambrian to Tertiary. They are

so widely distributed that for local supply there are numerous
small quarries in many states, but there are several areas which
occur in
all
have been operated on an extensive scale, some of them for many

Of these, one of the best known is the Triassic Brownstone
years.
which
extends from the Connecticut Valley, in Massachusetts,
belt,
southwestward into North Carolina.
This is a red, brown, or even bluish sandstone, of moderate hardThat from the Connecticut
ness, and somewhat variable texture.
in
enormous
district
was
used
Valley
formerly
quantities.
Among
the Paleozoic strata there are
many
sandstones, often
Of these the Medina and

massive, and usually dense and hard.
Potsdam are specially important and much quarried in New York
State (34, 35).
The same formations extend southward along the
Appalachians and are available at several points. Devonian flagstones are extensively quarried at several localities in New York
At the present time the Lower Carboniferous
and Pennsylvania.
Berea sandstone of Ohio (37) is in great demand because of its light

Morecolor, even texture, and the ease with which it is worked.
over, it has the peculiar property of changing to a uniform buff on
exposure to the air. There are numerous other Paleozoic sandstones in the central states, among them the Potsdam, which covers
a wide area in Michigan and Wisconsin (51). Some of this stone is
bright red in color.
BUILDING STONES
159
The Mesozoic and Tertiary strata of the West contain an abundance of good sandstone, and quarries opened in many of them
yield a durable quality of stone.
Though usually less dense and
hard than the Paleozoic sandstones, they serve admirably for
buildings in the mild or dry climates of the West.
Uses of Sandstones.
The wide distribution of sandstones makes
them an important source of local structural material. They are
chiefly used for ordinary building work, and but little for massive
masonry or monuments. The thin-bedded flagstones are much
used for flagging, and some of the harder sandstones are split up for
paving blocks.
For other
uses, see Abrasives.
SLATES
General Characteristics
(9,
Slates are
25).
metamorphic rocks
derived from clay or shale or more rarely from igneous rocks (14).
Their value depends upon the presence of a well-defined plane of
splitting,
called cleavage (Fig.
57),
developed by metamorphism
through the rearrangement
and
flattening of the original
mineral grains and the de-
velopment
QUARRY "FLOOR
minerals.
micaceous
of
The cleavage usu-
ally develops at
a variable
angle to the bedding planes

57
FIG
Section showing cleavage and
are Qften comp l etely
wWch
bedding in slate.
(After Dale, U.S.
obliterated
by the metaGeol.
wth Ann.
.
Surv.,
Rept., III.)
morphism.
When
not com-
pletely destroyed, the bedding planes are marked by parallel bands,

called ribbons, cutting across the planes of cleavage, but so perfect
the cleavage in the best slates that the rock readily splits into
thin sheets with a smooth surface.
is
commonly so fine grained that the mineral composition

not evident to the eye, but the microscope reveals the presence
of many of the varied mineral grains found in shale, and in addition
much chlorite, developed by metamorphism. Owing to the presSlates are
is
ence of carbonaceous particles, most slates are black or bluish black,

but green, purple, and red slates are also known. The specific gravity of slate is about 2.7, and a cubic foot weighs between 170 and
175 pounds.
Most
slates are fairly durable,
though the presence of pyrite
ECONOMIC GEOLOGY
160
along the ribbons
may
Lime carbonate if
lead to their decay.
if the slate is to be used
present in any quantity is injurious, and

for switchboards, it should be as free
from
Some
magnetite grains as possible.

colored slates fade on exposure to
the weather, but this change, which is

due to the bleaching of certain mineral
grains, does not necessarily result in loss
of strength or disintegration.
of
importance to
distinguish between bedding
and cleavage.
In slate quarrying
it
is
The following criteria may be used (43a).

Quartzite and limestone bands of some persistence indicate bedding, but care must be
taken not to mistake vein quartz for quartzalways on the
microscopic section, transcleavage, may be used, if other
Fossil impressions are
ite.
bed surface.
verse
to
FIG.
Section
58.
in
slate
quarry with cleavage parallel to bedding,

a, purple
slate; b, unworked; c and d,
variegated; e and/, green; g
and
ite;
gray-green;
h,
j,
gray
i,
with
quartzblack
patches.
(After Dale.)
to indicate divergence between
bedding and cleavage, although in some places the two may agree.
Special tests are necessary for determining the quality of slate.
They
means
fail,
include the determination of its sonorousness, cleavability, abrasive resistThe chemiance, absorption, elasticity, and presence of injurious minerals.
cal analysis is of limited value, but Merriman concludes that the strongest
slate runs highest in silica and alumina but not necessarily lowest in lime
and magnesium carbonates.

Dale divides slates into the following groups:
I. Aqueous sedimentary.
A. Clay slates: cemented by clay, lime carbonate, or magnesium
carbonate. Fissility, strength, and elasticity low.
B. Mica slates:
1. fading; with sufficient iron carbonate to dis2. Unfading; without sufficient iron
on exposure.
carbonate to produce any but very slight discoloration on
color
prolonged exposure.
Under each group we may have the following types: Graphitic

(gray-black); chloritic (greenish); hematitic and chloritic (purplish). The second group may also include hematitic (reddish).
II.
Igneous.
A. Ash slates.
B. Dike slates.
Distribution of Slates in the United States (Fig. 59).

Since
metamorphic origin, they are limited to those regions
in which the rocks are metamorphosed, and at present the greater
slates are of
part of our supply comes from the Cambrian and Silurian strata of
the eastern crystalline belt of the Atlantic states.
ECONOMIC GEOLOGY
162
A series of quarries producing, red, green,

are
slates
located in a
purple, and variegated

Cambrian and Hudson River
New York (33) (PL XX) and Vermont
belt
strata along the border of
of
(33, 45).
Black
slates
are quarried in
Maine
(3),
New
Jersey
(32),
(PL XIX, Fig. 2), Maryland (26), Georgia (3),

Pennsylvania
and Virginia (46). Other producing states are Minnesota, California (14, 43a), and Arkansas (12).
Slate is best known as a roofing material,
Uses of Slate.
(3),
but
it
is
also used for mantels, billiard-table tops, floor tiles,
steps, flagging, slate pencils, acid towers, washtubs, etc.

process of marbleizing slates for mantles and fireplaces
The
was
formerly carried on at several localities.

In quarrying slate there is from 60 to 80 per cent waste, which
is greater than in any other building stone; but the introduction
machines in quarrying has done much to reduce

of a use for this waste has been an important problem, which has thus far been only partially solved.
It is sometimes ground for paint, and attempts have been made
to utilize it in the manufacture of bricks and Portland cement.
The Canadian building
Building Stones in Canada (52a)
of channeling
this.
The discovery
stones are developed chiefly in the eastern provinces, including

Ontario, and in the far West, as along the Pacific Coast.
Nova Scotia and New Brunswick
Igneous Rock (52o)
.
contain a
number
of granite areas, yielding stone of varying
texture and color, the red variety quarried near St. George, N. B.,
being well known. There is also considerable local development
around Halifax.
Nova
Scotia has
much
fine-grained,
dense
volcanic rock, susceptible of decorative use. Some diorite and

diabase for monumental w ork is also quarried in New Brunswick.
r
In
Quebec granites and gneisses are worked at scattered
points in the northern area, but the gray granite of the Stanstead district in the eastern townships is the best known, while
so-called black granite (essexite) for monumental purposes is
quarried in the Monteregian Hills.

Ontario granites and gneisses
though abundant are
little
developed.
Not a little granite is quarried along the Pacific Coast north
of Vancouver, and the andesite from Vancouver Island is quite
extensively used.
PLATE XX.
View
of green-slate quarry, Pawlet, Vt.
(Photz. by
H.
(163)
Ries.)
ECONOMIC GEOLOGY
164
Limestones of Paleozoic age are extensively

Limestones.
quarried in Quebec,, notably around Montreal and Hull, and
at manjr points in southern Ontario.
West of Winnipeg a peculiar
mottled limestone is quarried, and much used in Manitoba.
Sandstones. The Carboniferous sandstones of New Brunswick
and Nova Scotia, and the Ordovician and Silurian sandstones of
Quebec and Ontario have been developed at many points. Ocsionally sandstone deposits are worked in the Cretaceous and
Tertiary beds of the Western Provinces, and also on Vancouver
Island.
Marble.
Highly decorative marbles of pre-Cambrian age
are quarried at South Stukely, Quebec.

Paleozoic ones of gray
and green color, with veins and cloudings, are obtained near
Phillipsburg in the
same province.
Crystalline limestones are
but the best known variegated marble is

that quarried near Bancroft. A gray and white marble is obtained
in the Kootenay district of British Columbia.
Slate.
Little good slate is obtained in the Dominion, this
from
the easiern townships of Quebec.
coming
abundant
in Ontario,
Other Foreign Building Stones.
Granites
are
quarried at a
number
of localities in Europe, but those exported to the United States, and used
more or less for monumental purposes, come chiefly from Scotland and
Sweden.
Of the many foreign sandstones quarried, the bright-red Scotch ones have
been used in some quantity in the United States.
Volcanic tuffs are widely distributed and abundantly used in central
Mexico, and these, together with lava rock, have been frequently quarried
in Italy, the Auvergne region of France, and even other localities.
The roofing slates found in the Cambrian and Orodvician of North Wales
are among the best knov. n deposits of the w orld.
Many lirr estones are quarried, especially in

Among these IT ay be nrentioned the
tions.
the post-Carboniferous formaPortland stone of the Jurassic
on the Isle of Portland, near Weymouth, and the soft French lirr estones,
of which the Caen stone, often used in America for interior work, are well
known. Another soft, but dense limestone, capable of taking a polish,
and frequently employed here, is that of Hauteville, France.
Marbles of great beauty are quarried in many foreign countries, and
widely exported. Among the best known are: White statuary marble
from Carrara, Italy; yellow, black-veined Sienna, and whitish, veined
Pavonazzo, from the same country; Skyros breccia from Greece; Griotte
or red from France; Parian white from Greece; banded Cippolino from
Many of them are of highly decorative
Switzerland, and a host of others.
character, but of low weather-resisting qualities.
The same is true of the beautiful serpentine marbles, which
tained from Ireland, Italy, and Greece.
may
be ob-
BUILDING STONES
165
Production of Building Stones.

The production of building
by kinds for the last 5 years was as follows:
stones
PRODUCTION OF BUILDING STONES IN THE UNITED STATES FROM 1910 TO 1914

KIND.
ECONOMIC GEOLOGY
166
PRODUCTION OF BUILDING STONES IN MORE IMPORTANT STATES IN 1914

STATE.
BUILDING STONES
The following figures
Exports and Imports.
of the exports for the years 1913 and 1914:
167
show the value
EXPORTS OF STONE FROM THE UNITED STATES IN 1913 AND 1914

KIND.
ECONOMIC GEOLOGY
168
1896.
Siebenthal, U. S.
22.
1898.
(Bedford limestone.)
Surv., 17th Rept.: 19, 1891.
Geol. Surv.,
19th Ann. Rept., VI: 292,
Thompson, Ind. Geol. and Nat.

Iowa: 23o. Beyer and
(General.)
23.
iams, la. Geol. Surv., XVII: 185, 1907.

(General.)
Ibid., 541, 1907.
(Tests.)
Kentucky: 23c. Crump,
4th
I:
ser.,
1914.
1037,
(Oolitic
limestone.)
Hist.
Will-
236. Marston,
Ky. Geol. Surv.,

Maine: 24. Merrill,
Stones for Building and Decoration. Wiley & Sons, New York, 1904.
25. Dale, U. S. Geol. Surv., Bull. 586, 1914.
(Slate), 25a. Dale,
U. S. Geol. Surv., Bull. 313, 1907.
(Granite.)
Maryland: 26.
Massa1898.
(General.)
Surv., II:
125,
1907.
S. Geol. Surv., Bull. 313,
(Granites.)
28. Dale, U. S. Geol. Surv., Bull. 354, 1908.
(Granites.)
Michigan:
Mis29. Benedict, Stone, XVII: 153,
1898.
(Bayport district.)
Matthews,
chusetts^
Md.
Geol.
U.
27. Dale,
Buckley and Buehler, Mo. Bur. Geol. and Mines, Vol. II,
Montana: 30o. Rowe, Univ. Mont., Bull. 50. (General.)
New Hampshire: 31. Dale, U. S. Geol. Surv., Bull. 354, 1908.
New Jersey: 32. Lewis, N. J. Geol. Surv., Ann. Rept.,
(Granites.)
souri:
30.
1904.
1908: 53, 1909.

Bull. 586.
New
(General.)
(Slate
York: 33. Dale, U. S. Geol. Surv.,

N. Y. State Museum, Bull.
34. Dickinson,
belt.)
(Bluestone and other Devonian sandstones.) 34a. Newland,

N. Y. State Museum, Bull. 181, 1916. (General.)
35. Smock, N. Y.
State Museum, Bull. 3, 1888.
North Carolina: 36. Watson, Laney,
and Merrill, N. Ca. Geol. Surv., Bull. 2, 1906. (General.)
Ohio:
Ohio Geol. Surv., V:
1884.
37. Orton,
37o.
(General.)
578,
Orton and Peppel, Ibid., 4th ser., Bull. 4, 1906. (Limestones.)
61, 1903.
Oklahoma:
5:
31,
1909.
38. Gould,
1911.
Okla. Geol. Surv., Bull.
1:46, 1908, also Bull.

38a. Darton, U. S. Geol., Surv. Bull. 387,
I:
386. Parks, Min. Res.
1914.
Ore.,
10,
Oregon:
(Limestones.)
Pennsylvania: 39. Hopkins, Penn. State College, Ann. Rept., 1895;

Appendix, 1897; also U. S Geol. Surv., 18th Ann. Rept., V: 1025,
1897.
(Brownstones.) 40. Lesley, Tenth Census, U. S., X:
146,
1884.
1913.
354,
40a. Hice, Top. and Geol. Com. Pa., Bull. 9: 98,

(General.)
Rhode Island: 41. Dale, U. S. Geol. Surv., Bull.
(Marbles.)
1908.
South Carolina: 41a. Sloan, S. Ca. Geol.
(Granites.)
Surv.,
ser.
IV,
Bull.
Dak. Geol. Surv.,
2:
Bull.
162,
3:
19C8.
81,
1902.
South Dakota: 42. Todd,

Tennessee:
(General.)
S.
43.
Gordon, Tenn. Geol. Surv., Bull. 2, 1911. (Marbles.) See also Ref. 2.
Texas: 43a. Burchard, U. S. Geol. Surv., Bull. 430.
Vermont
44. Perkins, Rept. of State Geologist on Mineral Industries of Vt.,
1899-1900, 1900, 1903-1904, 1907-1908; and 45. Report on Marble,
45a. Dale, U. S. Geol. Surv.,
Slate, and Granite Industries, 1898.
Bull. 521, 1912, and 589, 1915.
(Marbles.)
Virginia: 46. Watson,
Mineral Resources of Va., Lynchburg, 1907.
47. Dale, U. S. Geol.
Surv., Bull. 586, 1914. (Slate.)

Washington: 48. Shedd, Wash. Geol.
1902.
West Virginia: 49. Grimsley, W.
Surv., II:
3,
(General.)
Va. Geol. Surv., Ill, 1905. (Limestones.) 50. Ibid., IV: 355, 1909.
Wisconsin:
(Sandstones.)
Surv.,
Bull.
and Min.
IV,
Jour.,
1898.
LXVI:
51.
Buckley,
(General.)
546, 1898.
Wis. Geol. and Nat. Hist.
Wyoming:
52. Knight,
Eng.
BUILDING STONES
Canada:
52a. Parks, Can.
Stones:
1912 (Ont.),
I,
169
Mines Branch, Reports on Canadian Building

II,
1914 (Maritime Provinces),
III,
1914 (Quebec).
REFERENCES ON ONYX MARBLE

53.
"Onyx Marbles,"
DeKalb,
557,
1896.
York), 3d
ed., 1904.
ington), 1895.
,
Trans.,
Am.
Inst.
Min.
Engrs.,
XXV:
Stones for Building and Decoration (New

55. Merrill, Ann. Rept. U. S. Nat. Mus. (Wash-
54. Merrill,
56. Merrill,
Min. and
Sci. Press,
Min. Indus., Vol.

C: 791, 1910.
II,
"Onyx/' 1894.
56a.
be defined as an earthy substance of

of hydrous aluminum silicates,
a
mixture
containing
with fragments of other minerals, such as silicates, oxides, carbonates, etc., and colloidal material which may be of either
Definition.
Clay
may
fine texture
The mass possesses plasticity

character.
rock-hard when fired to at
becomes
and
wet,
(usually)
least a temperature of redness.
or
organic
mineral
when
Two
important classes
ported ones.
Residual Clays
cipally
(8).
of clays are the residual
and the trans-
Clays are derived primarily and prin-
from the decomposition of
crystalline rocks,
more espe-
cially feldspathic
va-
and deposits
thus formed will be
rieties,
found overlying the

parent rock and often
grading down on to
it.
From
its method
and position
termed a residual
of origin
it is
FIG. 60.
Section showing formation of residual clay.
(After Ries, U. S. Geol. Sun., Prof. Pap. 11.)
amount
Clay (rig.
o(J).
^11 residual clays probably contain a variable
of kaolinite (8) or clay substance.

This mineral, which is white in
from the decorr. posit ion of feldspar, either by weathering, or,
color, results
by the action of volcanic vapors. The decay of a large mass of

pure feldspar would therefore yield a mass of white clay, but, in most instances,
the feldspar is associated with other minerals, such as quartz, mica, and
less often,
all of which, except the quartz, and muscovite, decay with

greater or less rapidity, and some of these, such as the hornblende, may
likewise yield a hydrous aluminum silicate.
Any ferruginous minerals in
the rock will, in decomposing, yield limonite, which stains the mass.
hornblende,
Large masses of pure feldspar are rare, but feldspathic rocks, such
as granite or syenite, are more common, and these will also decompose
to clay; but, since the parent rock contains other minerals, such as quartz
or mica, these will either remain as sand grains in the clay, or,
170
by decom-
CLAY
position, will form soluble
as well as crystalline ones
limestone
is
171
compounds, or iron stains.

produce residual clay.
may
the insoluble clayey impurities
left after
Sedimentary rocks
That derived from

the carbonates are
dissolved.
The extent of a deposit of residual clay will depend on the extent of the
parent rock and the topography of the land, which also influences its thickness.
On steep slopes much of the clay may be washed away; and residual
clays are also rare in glaciated regions, for the reason that they have been
swept away by the ice erosion. They are consequently wanting in most
of the Northern states, but abundant in many
parts of the Southern states,
where the older formations appear at the surface.
With the erosion of the land surface

Transported Clays (8).
the particles of residual clay become swept
away to lakes, seas, or
the ocean, where they
settle down in the
quiet water as a fine
LOAMY CLAY'
CLAY
aluminous sediment,
forming a deposit of
SAND
SAND AND GRAVEL
sedimentary clay (Fig.

Such beds are
61).
often of great thickness and vast extent.
FIG. 61.
tion of
Section of a sedimentary clay deposit.
(After Ries, U. S. Geol. Surv., Prof.
With the accumula-
Pap.
11.)
on top of them, they become

deposit of a cement around
the grains.
Consolidated clay is termed shale, and this upon
being ground and mixed with water often becomes as plastic as an
many
feet of other sediments
consolidated either
by pressure or by the
unconsoliclated clay.
Residual materials
may
also
have been transported by wind or
glacial action, to form clayey deposits.

The following are important types of transported clays
Formed by
the deposition on the ocean floor of the

from the waste of the land. Such ancient seabottom clays have been elevated to form dry land in all the continents, in
Marine
Clays.
finer particles derived
cases forming consolidated clay strata, but elsewhere, especially in

Extensive clay deposits are
coastal plains, in unconsolidated condition.
also formed in protected estuaries and lagoons along the seacoast.
many
Formed by the deposition of clayey sediment on

Flood-plain Clays.
the lowlands bordering a river during periods of flood.
Layer upon layer,
Such
this deposit builds a flood plain often of great extent and depth.
areas of flood-plain clays are most extensive along the greater rivers and
in the deltas which they have built in the sea.
Lake Clays.
Clay is deposited on the bottom of many lakes and
ponds in the same manner as on the ocean bottom. Where the streams
ECONOMIC GEOLOGY
172
bring only fine particles the filling of a lake may be entirely of clay. Many
lakes have been either drained or completely filled and their clays thereThis is especially true of small, shallow lakes formed
fore made available.
during the Glacial Period.
commonly known
as till or bowlder clay, a rock flour

which rock fragments were worn down to
clay by being rubbed together or against the bed rock over which the
When the ice melted, this deposit was left in a sheet of varying
ice moved.
thickness and characteristics over a large part of the area which the ice
It is not always, strictly speaking, a sedimentary deposit.
covered.
Wind drifts dry clay about, and in favorable posiMolian Clays.
This is true of the Chinese loess,
tions causes its accumulation in beds.
a wind-blown deposit derived from residual soils and drifted about in
Glacial Clays,
ground in the
glacial mill in
the arid climate of interior China.

Mississippi Valley
glacial deposits;
seem
Some
at least of the loess clays of the
have a similar origin, the source of the clay being

other cases loess seems to be a water deposit either in
in
to
shallow lakes or else in broad, slowly moving streams.
Properties of Clay.
cal,
and
These are of two kinds, physical and chemian important influence on the behavior
since they exercise
most important ones may be described.

These include plasticity, tensile
Physical Properties (8, 1).
fire
air
and
strength,
shrinkage, fusibility, and specific gravity.
of the clay, the
Plasticity may be defined as the property which clay possesses of forming

a plastic mass when mixed with water, thus permitting it to be molded into
any desired shape, which it retains when dry. This is an exceedingly important character of clay. Clays vary from exceedingly plastic, or "fat"
ones, to those of low plasticity which are "lean" and sandy.
Plasticity
is probably due in part to fineness of grain, and in part to the presence of
colloids
(1, 6a, 8).
the resistance which a mass of air-dried clay offers

probably due to interlocking of the particles and set
Tests show that the tensile strength of clays varies from 15 to
colloids.
20 pounds per square inch up to 400 pounds or more per square inch. Many
common brick clays range from 100 to 200 pounds.
Tensile strength
to rupture,
and
is
is
is of two kinds
air shrinkage and fire shrinkage.
The fortakes place while the clay is drying after being molded, and is due to the
evaporation of the water, and the drawing together of the clay particles.
Shrinkage
mer
The
latter occurs during firing, and is due to a compacting of the mass as

the particles soften under heat. Both are variable.
In the manufacture
of most clay products an average total shrinkage of about 8 or 9 per cent
Excessive air or fire shrinkage causes cracking or

this a mixture of clays is often used.
When
Fusibility is one of the most important properties of clays.
subjected to a rising temperature, clays, unlike metals, soften slowly, and
hence fusion takes place gradually. In fusing, the clay passes through
is
commonly
desired.
To prevent
warping of the
clay.
three
termed,
stages,
viscosity.
respectively,
incipient
fusion,
vitrification,
and
CLAY
173
In the lower grades of clay, that is, those

having a high percentage of
fluxing impurities, incipient fusion may occur at about 1000
C., while in
refractory clays, which are low in fluxing impurities, it may not occur until
1300 or 1400 C. is reached. The temperature interval
between incipient
fusion and vitrification may be as low as 30 C. in
calcareous clays, or as
much as 200 C. in some others. The recognition of this variation is of
considerable practical importance, and vitrified
products, such as paving
bricks and stoneware, have to be made from a
clay in which the three stages
of fusion are separated by a distinct
temperature interval. The importance
of this rests on the fact that it is impossible to control the
temperature of a
large kiln within a few degrees, and there must be no danger of
running
into a condition of viscosity in case the
clay is heated beyond its point of
vitrification.
Specific gravity varies
Chemical Properties
commonly from about

(8).
1.70 to 2.30.
The number
of
common
elements
which have been found in clays is great, and even some of. the rarer
ones have been noted; but in a given clay the number of elements
is usually small, being
commonly confined to those deterin the ordinary chemical analyses, which show their existence
present
mined
in the clay,
but not always the state of the chemical combination.
The common
constituents of a clay are silica, alumina, ferric or

ferrous oxide, lime, magnesia, alkalies, titanic acid, and combined
water.
Organic matter, and sulphur trioxide, though often presCarbon dioxide is always found
ent, are usually in small amounts.
in calcareous clays.
The
effect of these
may
be noted
briefly.
Silica if present in the form of quartz or other crystalline grains, aids in

lowering the plasticity and shrinkage at low temperatures. Silica in colloidal
form probably increases the plasticity (6a). A lumina, which is most abun-
dant in white clays, is a refractory ingredient. Iron oxide acts as a coloring

agent in both the raw and burned clay, small quantities usually coloring
a burned clay buff, and larger amounts (4 to 7 per cent), if evenly distributed,
turning it red. It also acts as a flux in burning. Whatever the iron compound
present in the raw clay it changes to the oxide in burning. Lime, magnesia,
The combined peralkalies are also fluxing ingredients of the clay.
and
centage of fluxing impurities is small in a refractory clay, and often high

in a low-grade one.
Lime, if present in considerable excess over the iron,
For this reason,
will, in burning, exert a bleaching effect on the latter.
highly calcareous clays, such as those in the Great Lake region, burn cream
or buff. When lime is present in large amounts, it also causes clay to soften
more rapidly in firing than it otherwise would.
Chemically combined water passes
off chiefly
and carbonaceous matter mostly between 800
between 450 and 650 C.,

This losa
and 900 C.
Titanic acid,
leaves the clay temporarily porous until fire shrinkage sets in.
though rarely exceeding 1 per cent, acts as a flux at high temperatures at
ECONOMIC GEOLOGY
174
least.
Sulphur
trioxide is rarely present in sufficiently high

burning of the clay.
amounts
to in-
terfere with the successful
colors a raw clay gray or black, and several per cent may give
trouble in burning, unless driven out of the clay before it becomes
Carbon
much
dense.
As might be expected from their diverse

vary widely in their chemical composition.
every gradation from those which, in composition, closely
modes
There
of origin, clays
is
resemble the mineral kaolinite, to those, like ordinary brick clays,

in which there is a high percentage of impurities.
This variation
is
shown
in the opposite table.
The absence of ferrous oxide, titanic

matter, and manganous oxide in many
oxide, sulphur trioxide, organic

of the analyses (p. 175) does
not necessarily indicate their non-existence in these clays. Probably all

contain at least small percentages of these substances, but they are rarely
determined.
It is possible to base a classification of clays
Classification of Clay.
either
on
origin,
chemical and physical properties, or uses. But since the

made are not sufficiently distinct, each of these
subdivisions which can be

gives rise to a
fication
acters
is
(8)
more
or less unsatisfactory grouping.
following classi-
A. Residual clays.
I.
The
based partly on mode of origin and partly on physical char-
(By decomposition
of rocks in situ.)
Kaolins or china clays (white-burning).

(a) Veins, derived from pegmatite, rhyolite, etc.
(6) Blanket deposits, from areas of igneous or metamorphic rocks.
(c) Pockets in limestone, as indianaite (24).
(Origin doubtful.)
(d) Bedded deposits from feldspathic sandstones.
IT. Red-burning residuals, derived from different kinds of rocks.

B. Colluvial clays, representing deposits formed by wash from the fore-*
going, and of either refractory or non-refractory character.
C. Transported clays.
I.
Deposited in water.
(a)
Marine clays or
White-burning
shales.
clays.
Deposits often of great extent.

Ball clays
and
plastic kaolins.
Fire clays or shales.
Buff-burning.
Calcareous.
,
,
Impure clays or shales. XT
Non-calcareous.
Lacustrine clays (deposited in lakes or swamps).
,
(6)
Fire clays or shales.

Impure clays or shales, red-burning.
Calcareous clays, usually of surface character.
(c)
(d)
Flood-plain clays. Usually impure and sandy.

Estuarine clays (deposited in estuaries). Mostly impure and
finely laminated.
CLAY
ANALYSES SHOWING VARIATION IN COMPOSITION OF CLAYS
175
ECONOMIC GEOLOGY
176
II.
Glacial clays, found in the drift,

red- or cream-burning.
and often stony.
May either
be
III. Wind-formed deposits (some loess).

D. Chemical deposits (some flint clays?).
Kinds of Clays.
Many kinds of clays are known by special
names, which in some cases indicate their use, but in others refer
The more important ones
partly to certain physical properties.
are the following
Adobe. A sandy, often calcareous, clay used in the west and southBall day. A white-burning, plastic,
west for making sun-dried brick.
sedimentary clay, employed by potters to give plasticity to their mixture.

Brick clay. Any common clay suitable for making ordinary brick.
China
A term applied to kaolin (q.v.). Earthenware clay. Clay suitable
clay.
for the manufacture of common earthenware, such as flower pots.
Fire
A clay capable of resisting a high degree of heat. Flint clay. A
clay.
fire clay, which when ground up and wet develops no
Chemically, it differs but little, if at all, from the plastic fire
Moreover, the two often occur in the same bed, either in separate
clays.
Gumbo. A very sticky, highly plastic clay,
layers or irregularly mixed.
occurring in the central states, and used for making burned-clay ballast (2).
peculiar flint-like
plasticity.
Kaolin. A white-burning residual clay, employed chiefly in manufacture of

white earthenware and porcelain. The term is also applied by some to the
Loess. A
white-burning sedimentary clays of Georgia and South Carolina.
sandy, calcareous, fine-grained clay, covering thousands of square miles in
the central states, and of wide use in brick making.
Paper clay. Any
fine-grained clay, of proper color, that can be employed in the manufacture
of paper.
Pipe clay. A loosely used term applied to any smooth plastic
clay. Strictly speaking, it refers to a clay suited to the manufacture of sewer
Pot clay. A dense-burning fire clay, used in the manufacture of glass
pipe.
The domestic supply comes mainly from St. Louis, Missouri, but
pots.
much
is
pottery.
term
is
Pottery clay. Any clay suitable for the manufacture of

Retort clay.
The
plastic fire clay, used in making gas retorts.
a local one used chiefly in
loose term
Jersey.
Sagger clay.
imported.
New
applied to clays employed in making saggers; they are of value for other
purposes as well. Sewer-pipe clay. A term applicable to any clay that can
be used for manufacture of sewer-pipe.
It is usually verifiable and red-
Under this term are included those clays which are

and form a natural glaze, when applied to ware (such as
stoneware) and burned at the proper temperature. The best-known variety
comes from Albany, N. Y. Stoneware clay. A very plastic clay, which
burning.
Slip clay.
easily fusible,
burns to a
vitrified or stoneware body.

Terra-cotta
It may be refractory.
Clay suitable for the manufacture of terra cotta. The term has
no special significance, as a wide variety of clays are adapted to this
clay.
purpose.
Geological Distribution.
Clays have a wider distribution than
most other economic minerals or rocks, being found in all forma-
PLATE
FIG.
FIG.
1.
2.
XXI
Kaolin deposit, North Carolina, shows circular pits for mining, sunk ia
clay.
(PhoLo loantd by Southern Railway Company.)
Bank
of
sedimentary clay, Woodbridge, N. J. This section affords at

least five kinds of clay.
(Photo., H. Ries.)
(177)
ECONOMIC GEOLOGY
178
from the oldest to the youngest. The pre-Cambrian crystalboth white and colored residual clays, usually the result
of weathering, though more rarely of solfataric action.
In the
Paleozoic rocks, deposits of shale, and sometimes of clay, are found
in many localities; and, since they are usually marine sediments,
the beds are often of great extent and thickness.
The weathered
tions
lines yield
outcrops of these may yield a residual clay. With the exception of

certain Carboniferous deposits, the Paleozoic clays are mostly im-
The Mesozoic formations contain large supplies of clays

pure.
and shale suitable for the manufacture of bricks, terra cotta, stoneware,
fire brick, etc.
The
Pleistocene clays are all surface deposits, usually impure,

of limited extent, although they are thickly scattered all over the United States.
Their chief value is for brick and
and individually
tile
making.
They have been accumulated by
glacial action,
on
flood plains, in deltas, or in estuaries and lakes.

Distribution of Clays by Kinds in the United States.
Kaolins
Kaolins proper are derived only from crystalline or igneous
rocks, hence their distribution is limited, and the only deposits
worked are in the eastern states. Being commonly formed
(67).
by the weathering of pegmatite veins, kaolin deposits have great

length as compared with their width, which may be anywhere
from 5 to 300 feet. Their depth ranges from 20 to 120 feet,
depending on the depth to which the feldspar has been weathered.
CLAY
179
contents have been considerably lowered, and that the washed product
approaches more closely to the composition of kaolinite.
North Carolina
(52)
and Pennsylvania
(58, 56)
are the
most im-
portant residual kaolin-producing states, but deposits are also

worked in Connecticut (17 a), Maryland (36), and Virginia (67).
It is known to occur in Alabama (10).
All of these deposits except that in Connecticut are found south of the limit of the glacial
Kaolins occur in southeastern Missouri, but they have never
drift.
become
of great
importance
The Cretaceous
(45).
and South Carolina (61)

(20),
contains important deposits of white-burning sedimentary clays,
which might perhaps be termed plastic kaolins to distinguish
of
Georgia
them from the residual ones.

The output from the American
deposits is insufficient to supply

the domestic clay-working industry, and consequently many thousand tons are annually imported from England. Since this can be
brought over as ballast, it is possible to put it on the American

market at a low price. The best grades of kaolin sell for $10 to
at Trenton, New Jersey, and East Liverpool,
Ohio, these being the two most important pottery centers of this
$12 per ton

country.
Fire Clays.
Fire clays are found in the rocks of all systems,

from the Carboniferous to the Tertiary, inclusive, with the exception of the Triassic.
The most extensive, and among the most important, beds of fire
clay are those found in the Carboniferous strata of Pennsylvania
(56, 60), Ohio (54, 55), Kentucky (29, 30, 33), West Virginia (72),
Maryland (36), Indiana (24), Missouri (45), and Illinois (21, 22).
Those of the first two named states are on the average the most
Here the fire clays are usually found underlying coal
refractory.
seams and often at well-marked horizons, especially in the Upper
Productive Measures.
The
section given in Fig. 2
is fairly
representative of their
mode
of occurrence.
Those of Indiana and Illinois are so placed that one mine shaft
may be used for extracting coal, fire clay, stoneware clay, and shale.
The beds of refractory clay, found in the Carboniferous strata
near St. Louis (45), are not only used in the manufacture of fire
brick, but are, in some cases, found suitable, after washing, for
mixture with imported German clays for the manufacture of glass
pots.
ECONOMIC GEOLOGY
180
In the Lower Cretaceous of
New
Jersey (49) there are
many beds
of refractory clay, variable in thickness and closely associated with

beds of less refractory character. They not only support a thriving
local fire-brick industry,
tories in other states.
but serve also as a source of supply for fac-
Similar, but less extensive
and
less refractory,
beds occur in strata of Cretaceous Age in the coastal plain of Maryland (36), Georgia (20), South Carolina (61), and Alabama (10).
The Tertiary formations

abundant deposits
of
Texas
(64)
of refractory material,
The Missouri Tertiary
also supplies
and Mississippi
(44)
hold
but many are undeveloped.
some
fire
clays (45).
Fire clays are found in the Black Hills of South Dakota (62), in the
of Colorado (14-17), and in California (13); but, excepting
near Denver, where used for making fire brick and assayer's apparatus,
Laramie beds
these deposits are as yet slightly developed.
Under this heading are included several grades

Pottery Clays.
of clay, the kaolins, already described, being the purest and best
suited to the manufacture of high grades of pottery.
Another high-grade pottery clay of more plastic character, the
A small
is of limited distribution in the United States.
in
the
Cretaceous
is
found
of
New
(PL
XXI)
(49),
Jersey
quantity
and a much larger amount in the Tertiary of western Kentucky
(29, 31) and Tennessee (63), and southeastern Missouri (45) and
ball clay,
Florida (19, 67). As in the case of kaolin, the domestic supply is

not sufficient to meet the demand, and large quantities of ball clay
are imported from England.
Stoneware clays form a third grade of pottery clays. They are
usually of at least semirefractory character, but differ from fire
Their
clays proper in burning dense at a much lower temperature.
distribution is essentially coextensive with that of fire clays; inLarge
deed, the two are often dug from the same pit or mine.
quantities are obtained in the Carboniferous of western Pennsylvania (56, 57) and eastern Ohio (55) and smaller amounts in the
New
Jersey Cretaceous formations
(49).
Stoneware clays, usually in the same area as the fire clays, are also ob(21), Indiana (24), Kentucky (29, 31), Tennessee (63),
Alabama (10), and Texas (64); and they occur also in Missouri (45), Iowa
(26), Colorado (15), and California (13).
tained in Illinois
Many
of the Pleistocene surface clays in various states are suffi-
ciently dense-burning to
factories.
be
used
locally
by small stoneware
CLAY
181
Brick and Tile Clays (67).

None of our states lack an abundant
of
brick
and
tile
supply
good
clays, and in many areas there are
extensive deposits near the large markets, and often near tide
In such cases the clay beds are exploited to an enormous
water.
extent.
In the northeastern states the Pleistocene surface clays are found

almost everywhere in great abundance, and are made use of in
places, especially near the large cities.
many
In the middle Atlantic states Columbian loams and clay marls are
an important source of brick material.
In Ohio, Illinois, and Indiana Pleistocene clays, in part of glacial,
and in part of flood-plain origin, are much used for brick and tile.
Impure Paleozoic shales are
also used in places, especially in the
paving brick, thousands of which are made

annually in Ohio. Northern Illinois, Michigan, and Wisconsin
draw their main supply of brick clays from the calcareous lake
manufacture of
vitrified
deposits.
Although glacial clays and flood-plain deposits are much used in

the states west of the Mississippi, the loess which occurs over a wide
area is probably even more important as a source of brick, while in
the southwestern states loess and adobe are important. Residual
clays, river silts, glacial clays, and other forms of clay are employed
in brick
making along the
Pacific coast.
Miscellaneous Clays of Importance.

Paper clays of good quality are
Much English kaolin is used
for by paper manufacturers.
much sought
for this purpose, but the domestic kaolins are' also drawn upon, especially
those of Georgia, South Carolina, North Carolina, southeastern Pennsylsmall amount of glasspot clay (45) conies from
vania, and Connecticut.
western Pennsylvania, but much more from eastern Missouri, and our chief
supply is imported. Terra-cotta clays are obtained from the same areas that
supply fire clays, New Jersey being the principal producer.
Kaolins.
Distribution of Clays in Canada.
Deposits are
formed
but
one
in
the
deposit
area,
glaciated
hardly expected
from feldspathic veins in quartzite has been worked near
Huberdeau, Que.
(80).
Extensive deposits occur in the Laramie of

southern Saskatchewan (79), and the Eocene delta deposits of
the Frazer Valley, British Columbia. The same materials are
utilized for pressed brick, terra cotta, and certain beds for stoneFire
ware.
Clays.
ECONOMIC GEOLOGY
182
The Carboniferous
Red-burning Clays and Shales.
Nova
Scotia
and
New
Brunswick
shales of
the Ordovician and
(78, 81),
and the Cretaceous and

Western Provinces (79) afford abundant
making building and paving brick, drain tile, fire-
Silurian shales
of
Ontario
82),
(77,
Tertiary shales of the

material for
proofing,
and
in
some
cases,
sewer pipe.
These are widely distributed through the

Surface Clays.
and
Dominion,
may be of the estuarine, lacustrine, floodplain
or glacial type according to their location and origin (77-82).
Those found in the Great Plains region are not infrequently
buff or cream burning, because of their calcareous nature.
Other Foreign Deposits.
The kaolin or china clay deposits
of the Cornwall, England, 1 district are the most important of
this type worked in the world, and supply a large export trade.
Equally well known, but of less extent, are similar deposits in
2
Fireclays are
France, Denmark, Bohemia, and Germany.
worked at a number of localities for domestic use, but the glasspot clays of Belgium and Germany have not only been used at
home, but also exported. So, too, have German clays employed
in making graphite crucibles.
So few people have even an approximate
Uses of Clay.
idea of the uses to which clays are put that it seems desirable
to call attention to them briefly.
In the following table an attempt
has been made to do this 3
:
Domestic.
Pottery of various grades; Polishing

bath bricks; Fire kindlers; Majolica stoves.
brick,
often
known
as
Brick; Tiles and Terra cotta; Chimney pots; Chimney flues;

Door knobs; Fireproofing ; Copings; Fence posts.
Closet bowls; Sinks, etc.; Sewer pipes; Ventilating flues; FounHygienic.
Structural.
dation blocks; Vitrified bricks.
-Ornamental pottery;
Decorative.
Terra cotta;
Garden furni-
Majolica;
ture.
Minor Uses.
Food adulterants; Paint
Pumps; Fulling
lations;
Chemical
apparatus;
cloth;
filler;
Paper
filling;
Securing soap;
Condensing
worms;
Ink
Electrical insu-
Packing
horses' hoofs;
bottles;
Ultramarine
manufacture; Emery wheels.

Refractory
Wares.
Crucibles
and
other
assaying apparatus;
Refractory
bricks of various patterns; Glass pots.
Engineering
Work.
Puddle;
Portland cement;
Railroad ballast;
conduits; Turbine wheels.
and Sands, London, 1911.

Die Nutzbaren Mineralien, II: 379, 1914.
Table compiled by R. T. Hill and modified by the author.
Searle, British Clays, Shales
Dammer and
Tietze,
Water
CLAY
183
Production of Clay and Clay Products.

Owing to the fact
that clays are usually manufactured by the producer, it is
necessary to give the value of the product, no record being kept
of value of the
raw material.
VAL.UE OF CLAY PRODUCTS PRODUCED BY THE NINE LEADING STATES, AND

TOTAL UNITED STATES PRODUCTION, 1910-1914
STATE.
184
ECONOMIC GEOLOGY
PRODUCTION OF CLAY PRODUCTS IN CANADA, 1912-1914
CLAY
185
(Denver Basin.) 15. Geijsbeek,

Surv., Mon. XXVII, 1896.
Clay Worker, XXXVI: 424, 1901. (General.) 16. Ries, Amer. Inst.
Min. Engrs., XXVII: 336, 1898. (Clays and Clay industry.) 17.
Shaler and Gardner, U. S. Geol. Surv., Bull. 315: 296, 1906.
Connecticut: 17a. Loughlin, Conn. Geol. Surv., Bull. 4, 1905.
Delaware:
18. Booth, Geol. of Delaware: 94 and 106, 1841.
Florida: 19. Ries,
Geol.
U. S. Geol. Surv., Prof. Pap. 11: 81, 1903. 19a. Matson, U. S. Geol.
Surv., Bull. 380: 346, 1909.
Georgia: 20. Veatch, Ga. Geol. Surv.,
Bull. 18, 1909.
21.
Illinois:
Many
scattered references in volumes on
of Illinois Geol. Survey, Resume of these in U. S.

Geol. Surv., Prof. Pap. 11, 1903. 22. Purdy and De Wolf, 111. Geol.
Economic Geology
Surv., Bull. 4:
Bull. 9, 1908.
131,
1907.
(Fire clays.)
23. Rolfe
and
others, Ibid.,
Indiana: 24. Blatchley, Ind.

(Paving-brick clays.)
Dept. Geol. and Nat. Hist., 20th Ann. Rept.: 23, 1896. (Carboniferous
Same author, 22d Ann. Rept.: 105, 1898. (N. W. Ind.)

references in other annual reports.
26. Beyer,
Iowa:
25.
clays.)
Scattered
Kansas:
Williams, and Weems, la. Geol. Survey, XIV: 29, 1904.
27. Prosser, U. S. Geol. Surv., Mineral Resources, 1892: 731, 1893.
28. See also Reports on Mineral Resources of Kansas, Kas. Geol. Sur-
Kentucky: 29. Ries, U. S. Geol. Surv., Prof. Pap.

vey, 1897-1901.
30. Many analyses in Ky. Geol. Surv., Chem. Rept. A,
11, 1903.
and
31. Gardner, Ky. Geol. Surv.,

1885, 1886, 1888.
(Western coal field and Jackson Purchase Region.)
32. Foerste, Ibid.
(Silurian, Devonian, Waverly, Irvine formations.)
33. Phalen, U. S. Geol. Surv., Bull. 285: 411, 1906.
(N. E. Ky.)
33a. Easton, Ky. Geol. Surv., 4th ser., I: 713, 1913 and Crider, Ibid.:
Louisiana: 34. Clendenin, Eng. and Min. Jour.,
589.
(N. E. Ky.)
LXVI: 456, 1898. 35. Ries, Preliminary Report on Geology of La.,
pts.
Bull.
2,
1,
3,
1905.
6,
264, 1899.
Maryland: 36. Ries, Md. Geol. Survey, IV, Pt. Ill:
Massachusetts: 37. Crosby, Technol. Quart., Ill: 228,
205, 1902.
1890.
(Kaolin at Blandford.) 38. Shaler, Woodworth, and Marbut,
U. S. Geol. Surv., 17th Ann. .Rept., I: 957, 1896. (R. I. and S. E.
I:
MichEng. and Min. Jour., LXVI: 245, 1898.

Mich. Geol. Surv., VIII: Pt. I, 1903. (Clays and
Minnesota: 41. Grout and Soper, Minn. Geol. Surv., Bull.
42. Winchell, Minn. Geol. Surv., Misc. publications, No. 8,
39. Whittle,
Mass.)
igan:
40. Ries,
,shales.)
11,
1914.
1881.
(Brick
Clays.)
1905.
Vol. 2,
No.
Bull. 6,
1909.
3,
Mississippi:
(N.
Missouri:
W.
Miss.)
43.
Logan,
Miss.
Geol.
Surv.,
44. Logan, Miss. Geol. Surv.,
45. Wheeler,
Mo.
Geol. Surv., XI,
1896.
New
Nebraska: 46. Neb. Geol. Surv., I: 202, 1903.
Hampshire: 47. Hitchcock and Upham, Report on Geology of New
New Jersey: 48. Cook, N. J. Geol. Surv.,
Hampshire, V: 85, 1878.
1878. (Special Report on Clays.) 49. Kummel, Ries, Knapp, N. J.
New Mexico: 50. Shaler and
Geol. Surv., Final Reports, VI, 1904.
(General.)
Gardner, U.
eld.)
eral.)
S.
Geol. Surv., Bull. 315: 296, 1906.

(Durango-Gallup
51. Ries, N. Y. State Museum, Bull. 35, 1900. (Gen-
New York:
North Carolina: 52. Ries, N. Ca. Geol. Surv., Bull. 13, 1897.
North Dakota: 53. Babcock and Clapp, N. D. Geol. Surv.,
Ohio: 54. Orton, Ohio Geol.
(General.)
Rept., 1906.
(General.)
4th Bien.
ECONOMIC GEOLOGY
186
Surv., VII:
45, 1893.
industries.)
55. Orton, Jr., Ibid., p. 69.
(Geology.)
Oklahoma:
55a. Snider,
Okla.
Geol.
Min. Res. Ore.,
(Clay
Bull.
Surv.,
7,
No. 7: 14, 1914.

Pennsylvania: 56. Hopkins, Pa. State College, Ann. Repts. as
(W. Pa.) Ibid., Append, to Rept. for 1899follows, 1897, Appendix.
57. Ibid., 1898-1899.
1900.
(S. E. Pa.)
(Philadelphia and vicinity.)
1911.
556. Williams,
Oregon:
I,
MM:
Many analyses in 2d Pa. Geol. Surv., Rept.

scattered references in Repts.
5,
4, C 4, C
58.
257, 1879,
etc.
5,
and
Resume
59.
60. Scattered papers

in U. S. Geol. Surv., Prof. Pap. 11: 208, 1903.
South Carolina:
in U. S. Geol. Surv., Bulls. 285, 279, 315, 256, 225.
South Dakota:
61. Sloane, Bull. I, S. Ca. Geol. Surv.,
(S. Ca.)
Tennessee: 63. Nelson,
62. Todd, S. D. Geol. Surv., Bull. 3: 101.
Min. Res. Tenn., II, No. 4, 1912. (W. Tenn.), and No. 11 (Henry
United States:
Texas: 64. Univ. of Tex., Bull. 102, 1908.
66. Ries,
65. Hill, U. S. Geol. Surv., Min. Res. 1891: 474, 1893.
U. S. Geol. Surv., 17th Ann. Rept., Ill: 845,1 896. (Pottery clays.)
County.)
67. Ries,
U.
S.
Geol.
Prof.
Surv.,
Pap.
11,
1903.
(Clays east of
Vermont: 68. Nevius, Eng. and Min Jour.,

River.)
LXIV: 189, 1897. (Kaolin.) 69. Ries, U. S. Geol. Surv., Prof. Pap.,
11: 133, 1903.
Virginia: 70. Ries, Va. Geol. Surv., Bull. 2, 1906.
Mississippi
(General.)
West
Surv., Ill, 1906.

Hist. Surv., Bull.
Wis.
Geol.
Wisconsin:
I, Eco.
Pt.
7,
Surv.,
72.
Virginia:
Bull.
Experiment Station,
Bull.
15,
Shedd, Rept. State College, 1910.

Grimsley and Grout, W. Va. Geol.
73. Buckley, Wis. Geol. and Nat.
71.
Washington:
(Coastal Plain.)
Series, 4, 1901.
1906.
1893.
14,
(General.)
Wyoming:
(General.)
74. Ries,
Wyo.
75. Knight,
76. Fisher,
U.
S.
Geol. Surv., Bull. 260: 559, 1905.
Canada: 77. Baker, Ont. Bur. Mines, XV, Pt. II, 1906. (Ont.) 78. Ries,
Can. Geol. Surv., Mem. 16-E, 1911. (N. S. and N. B.) 79. Ries and
(Western Provinces.) 80. Keele,
Keele, Ibid., Mem. 24-E, 25 and 47.
Ibid.,
B.)
Mem.
52, 1915.
82. Keele, Ibid.,
(Que.)
Summary
81. Keele,
Ibid.,
Rept., 1914: 87,
Mem.
1915.
44, 1914.
(Ont.)
(N.
CHAPTER V
LIMES AND CALCAREOUS CEMENTS
Limes and calcareous
Composition of Limestones (2, 43).
cements form an important class of economic products, obtained
from limestones by heating them to a temperature ranging from
The term limestone is applied
that of decarbonation to clinkering.
to one of the main divisions of the stratified rocks so widely distributed, both geologically and geographically, and formed under such
different conditions, that its composition varies greatly, this range
of variation becoming appreciable from an inspection of the following table, which contains a few selected types
:
ECONOMIC GEOLOGY
188
When limestones are calcined or

Changes in Burning (2).
"
burned
to a temperature sufficiently high to drive off volatile
constituents, such as carbon dioxide, water, and sulphur (in part),,
"
or, in
other words, to the point of decarbonation, the rock is left in

If heated to a still higher temless porous condition.
a more or
perature, the rock clinkers or fuses incipiently, but the temperature

of clinkering
depends on the amount of
siliceous
and clayey im-
purities in the rock.
Lime
(2,
43).
-Limestone free from or containing but a small
percentage of argillaceous impurities
is, by decarbonation, changed

which has a high affinity for water, and
"
which, when mixed with water, slakes," forming a hydrate of lime.
This change is accompanied by the evolution of heat and by swelling, and this action becomes the more marked the higher the per-
to quicklime, a substance
centage of lime carbonate in the rock, for the slaking activity

retarded by the presence of magnesia and especially by argil-
is
Limes may, therefore, be divided into

impurities.
"
"
limes and
meager
limes, depending on the rapidity
with which they slake and the amount of heat they develop in
laceous
"
"
fat
doing
so.
With an increase in clayey and siliceous

Hydraulic Cements.
impurities, the burned rock shows a decrease in slaking qualities,
and develops hydraulic properties, or sets when mixed with water,
and even under the same. Products of this type are termed cements, and owe their hydraulic properties to the formation during
burning of silicates and aluminates of lime. On mixing the burned
ground rock with water, these take up the latter and crystallize,
thereby producing the set of the cement.
Hydraulic cements can be divided into the following classes:
Pozzuolan cements, hydraulic limes, natural cements, and Portland
cements.
Pozzuolan Cement (2,53).

This is produced from an uncalcined mixture of slaked lime and a silico-aluminous material, such
as volcanic ash or blast-furnace slag.
This process was known to the ancients, and is named from its
The composition of an Italian
early use around Pozzuolano, Italy.
Pozzuolano earth
vary between the following limits:

Fe
O 3 5-22; CaO, 2-10; MgO, up to
2
52-60; ALA, 9-21;
kalies, 3-16; H 2 0, up to 12.
may
Si0 2
2;
al-
Schoch, Die Moderne Aufbereitung u. Wertung der Mortel Materialien, Berlin.
1896.
189
No
deposits of volcanic ash, for use in Pozzuolan cement, are

in the United States, although extensive deposits of
the material are known to occur in the Rocky Mountain and
worked
Coast states. It is said, however, that a mixture of

Portland cement and volcanic ash was extensively and satis-
Pacific
factorily used
in
the
construction of the Los Angeles
aque-
duct.
The manufacture
of slag
the United
cement has been started at several
(2), but the industry is at

present showing a contraction instead of an expansion. Moreover, the cement hardly meets the specifications for Portland
localities
in
States
cement.
Hydraulic limes
(2)
are formed
by burning a
siliceous limestone
to a temperature not much above that of decarbonation.

Owing
to the high percentage of lime carbonate, considerable free lime
appears in the finished product. Hydraulic limes generally have a

yellow color, and a gravity of about 2.9. They slake and set slowly,
strength unless mixed with sand. This class is of
importance in the United States, although small quantities
have, in the last few years, been produced in Maryland, Georgia,
and have
little
little
and
and
New York. They are, however, of great importance in Europe,

may be of interest to give a few analyses of the raw material
it
used abroad
(2)
ANALYSES OF HYDRAULIC LIME ROCKS
190
ECONOMIC GEOLOGY
Natural Rock Cements
(2,
43).
These,
known
also as
Roman
cement, quick-setting cement, and Rosendale c?ment, are made by

burning a silico-aluminous limestone (containing from 15 to 40 per
cent clayey impurities) at a temperature between decarbonation
and clinkering. The product shows little or no free lime. The
following analyses will give some idea of the range in composition of
natural cement rocks quarried in the United States
:
ANALYSES OF NATURAL CEMENT ROCKS

The
following are
some analyses
of the
burned material
ANALYSES OF SOME NATURAL ROCK CEMENTS
191
ECONOMIC GEOLOGY
192
sary to bring about a uniform distribution of the lime through the mass.
Shale is, however, used by only a few works.
Argillaceous limestone, mixed with a much smaller quantity of purer
limestone, as in Pennsylvania and New Jersey, is superior to a limestone
and clay mixture, because
less
thorough mixing and
fine grinding are re-
In such cements, even when grinding and mixing are incompletely

quired.
done, the particles of argillaceous limestone so closely resemble the proper
mixture in chemical composition as to affect the result but
The
following table gives the analyses of
used in manufacture of Portland cement
ANALYSES OF
LOCALITY
RAW MATERIALS
some
of the
little.
raw materials
USED FOR PORTLAND CEMENT
193
The raw materials must not only have the proper composition, but
they also must show proper physical character, extent, and location, with
As regards composition, 5 or 6 per
respect to market and fuel supplies.
cent magnesium carbonate is about the permissible limit. Chert, flint,
or sand are also undesirable impurities, and alkalies and sulphates should
not exceed 3 per cent.
than 55 per cent
less
(Al 2 O3+Fe 2 O3)
to
The
if non-calcareous, should not contain

nor more than 70 per cent, and the ratio of
should be about 1 3. High alumina clays are
clay used,
silica
SiO2
undesirable because they raise the vitrification temperature and quicken

the set of the cement.
The
following are analyses of Portland cement mixtures before

l
burning:
ANALYSES OF PORTLAND CEMENT MIXTURES

SiO-2
ECONOMIC GEOLOGY
194
importance in the Mississippi Valley

from Tennessee (52) to Michigan (35). Lime of excellent
quality is obtained from the Subcarboniferous in Iowa (23, 24),
Kansas (25), and Missouri (53), and from the Cretaceous in Texas
Limestones suitable for lime manufacture are also found in
(53).
numerous localities in the Pacific coast states (53).
series of rocks are also of
states
Hydraulic Limes
Largely because of the great abundance

which are of superior value, these materials,
though much used abroad, are of no importance in the United
(2)
of natural-rock cements,
States.
was stated that in 1906 and 1907 several natural cement

plants had been making and marketing a true hydraulic lime, but
little or none is made now.
Calcareous rocks for making
Natural Rock Cements (2, 43, 53).
natural cement are found at a number of points, the more important ones being given in summarized form in the following table
*
It
GEOLOGIC AGE OF NATURAL CEMENT ROCKS IN THE UNITED STATES

STATE
GEOLOGIC AGE
PLATE XXII
FIG.
FIG.
1.
2.
Quarry of natural cement rock, Cumberland, Md.
Natural cement rock quarry, Milwaukee, Wis.
(H. Ries, photo.)
(H. Ries, photo.)

(195)
196
FORMATION
ECONOMIC GEOLOGY

Scott, Kansas (25), slightly
are worked.
Cement rock
Kentucky
ville,
is
magnesian Carboniferous argillaceous limestones,
also obtained
(29),
197
in southeastern
probably the
Ohio
(44),
and at Louis-
second most important center in the
United States.
FIG. 62.
Geologic
through the Vlightberg at Rondout, N. Y.

Ingen, N. Y. State Mus., Bull. 69.)
map
(After van
Portland Cements.
Clay and limestone, in one form or another,
are so widely distributed throughout the United States that it
is possible to manufacture Portland cement at many localities,
ECONOMIC GEOLOGY
198
200 300 400 500 Feef
100
SECTION
FIG. 63.
I,
THROUGH MIDDLE OF VLIGHTBERG
Geologic sections through the Vlightberg, showing position of natural

rock cement beds. (After van Ingen, N. Y. State Mus., Bull. 69.)
and the geologic age

cian to Pleistocene
(Refs.
under different states). Twentysix

states were
making this
cement
in
1914,
from Ordovi-
of the materials used ranges

(53),
the
7 feet
Cementroch
factories
being spread over the country

from the Atlantic to the Pacific
(Fig. 68).
'
By far the most
important
district is the
in
Pennsylvania,
Valley
16-22 feet
Limestone
Pennsylvania.
Lehigh
which
supplies about 30 per cent of the
6 feet
Cement rock
domestic product.
The cement
ampton
and
belt lies in
Lehigh
North-
Pennsylvania (Fig. 65), and the

geologic Section
follows (50)
:
2-4 feet
sandstone
counties,
involved
is
as
5 feet
Cement rock
FlG
54.
_ Section
at Utica,
111.
in
cement quarries
(After Eckel.)
199
ECONOMIC GEOLOGY
200
Hudson River
or
("More
Trenton limestones,
No
Probably 500 feet thick.

boundary.
slate.
less
argillaceous
limestone.
slaty
Sharp
limestone,
the
cement rock.
[ Nearly pure limestones with some dolomitic beds.
Kittatinny dolomites and dolomitic limestones.
3000'
Some beds flinty, and lowest are siliceous.
j'
Cambrian
Pre-Cambrian rocks.
Basal conglomerates or quartzite.
Mainly
gneisses.
The lower member of the Trenton varies in its physical character,

and furnishes material to raise the lime content of the cement rock
for Portland cement manufacture. Its lime carbonate content varies
from 80 to 97 per cent, but occasionally drops to 70 per cent, while the
magnesian carbonate runs from 1.5 to 3 per cent. In a few it reaches
20 per cent, and these highly magnesian layers cause trouble in quarThe upper or slaty member of the Trenton grades into the
rying.
lower one.
folding,
The rocks
of this region have,
been bent into a complex
by post-Carboniferous
66 and 67),
series of folds (Figs.
Diagrammatic section two miles long extending northwest from Martin's

and 1 = Cambrian dolomite; 2 and 3
Creek, N. J., showing overturned folds.
Lower Trenton, rocks high in lime; 4~ cement rock, Upper Trenton, averaging
70 to 80 per cent CaCOs; 5 = Upper Trenton cement rock with less than 70 per
FIG. 66.
cent
CaCOs;
6 = Hudson River slate.
(After Peck, Econ. GeoL, III.)
whose axes trend northeast and southwest, and while the

in
folds are
many cases overturned, there is comparatively little faulting.

The cement rock extends as a continuous zone or belt of varying
width southwest across Northampton County from the Delaware to

the Lehigh River (Fig. 65), crosses into Lehigh County,
FIG. 67.
Diagrammatic section
Numbers same as
qua.
five miles long
in Fig. 66.
extending northwest from Catasau-
(After Peck, Econ. GeoL, III.)
201
ECONOMIC GEOLOGY
202
and ends abruptly at a point four and a
half miles west of
Coplay.
The same beds

Jersey (38).
Other States.
are found in the adjacent territory of
In the eastern half of
New York
(43)
New
the Ordovi-
cian and Silurian limestones form an inexhaustible supply of maIn the south central
terial to mix with Pleistocene surface clays.
part of New York the Tully limestone and Hamilton shales are
employed, while in the central and southwestern portion beds of
bog lime (PI. XXIII, Fig. 2), associated with surface clays, are
utilized.
Indiana (18-21) and Michigan (34-36) are imPortland

cement producing states. The abundance of
portant
Ohio
(46, 74),
bog lime and Pleistocene clays makes them the favorite materials,
notwithstanding the fact that beds of Paleozoic limestones occur
in each of the states.
Bog lime, although especially abundant

in Michigan, is found in many states lying east of the Mississippi
and north of the terminal moraine. It is precipitated from the
waters of ponds through the agency of minute plants, especially
Cham
(35).
In Kansas Carboniferous shales and limestones are used for
making Portland cement (25, 26, 28), and in Texas and Arkansas
the Cretaceous shales and chalky limestones are employed (13,
Alabama has a Cretaceous limestone of such com14, 53);
position that very little clay or shale has to be added to it (12).
Portland cement is also manufactured in North Dakota (53),
South Dakota (51), Utah (53), Colorado (53), and California
(15, 53).
Cement Materials
scattered over the
in Canada.
Portland cement plants are

In Quebec
east to west.
Dominion from
and Ontario the Paleozoic limestones are used, and mixed with
shales or surface clays, but a number of the Ontario plants are
employing bog lime for the calcareous ingredient of the cement.
As limestones are scarce on the Great Plains, there are few
cement plants in this area, but between Calgary and the Pacific
Coast, where Paleozoic and Mesozoic limestones are plentiful,
some half dozen plants have been established. There is also at
least one in operation on Vancouver island, which is using a
mixture of Cretaceous limestone and a metamorphosed dacite
or andesite. 1
1
C. H. Clapp, private communication.
PLATE XXIII
FIG.
1.
Limestone quarry
in
Lehigh cement
district,
Pennsylvania.
(H. Ries,
photo.)
FIG. 2.
Marl
pit at
Warners, N. Y.
The dark
underlain by clay.
streaks are peat, and the marl is
(H. Ries, photo.)

(203)
204
ECONOMIC GEOLOGY
205
Lime (43, 2).

The most important single use of
mixing with sand to form mortar, and many thousands
of tons are used annually for this purpose.
In addition to this
use lime is employed for a great variety of purposes, of which
Uses
lime
is
of
for
the following are the most important: as a purifier in basic

steel manufacture; in the manufacture of refractoiy bricks,
ammonium
sulphate, soap, bone ash, gas, potassium dichromate,

paper, pottery glazes, and calcium carbide; as a disinfectant;
as a fertilizer; as a polishing material; for dehydrating alcohol,
preserving eggs, and in tanning.
Cement
The use of hydraulic cement is

United States, this being specially
true of Portland cement, which is superseding natural cement
to a great extent, and is finding an increasing use in building
and engineering operations. For pavements, Portland cement
is probably more extensively used in America than in any other
country; and as an ingredient of concrete it is widely employed.
Blocks weighing as much as 65 to 70 tons have been made for
harbor improvements at New York City (5)
The Production cf Cement. The tables on pp. 205-207 give the
production of natural-rock and Portland cement. Those given
for the latter cover a greater period than those of the former,
and are grouped with figures of import and consumption in order
to show more clearly the tremendous growth of the American
Portland cement industry.
The diagram (Fig. 69) shows most clearly the remarkable
increase in the production of Portland cement, and the rapid
decrease in the natural cement production, the latter being now
of small importance in the cement industry.
The Portland-cement curve shows a rapid rise after 1895, this
Uses
of
(2,
5)
constantly increasing in the
year marking the introduction of powdered coal fuel in the rotary

kiln.
The sag in 1907 was due to financial troubles.
PRODUCTION OF PUZZOLAN CEMENT IN THE UNITED STATES, 1909-1914
YEAR
206
ECONOMIC GEOLOGY

PRODUCTION OF PORTLAND CEMENT IN THE UNITED STATES IN
STATES
STATE
207
1914,
BY
ECONOMIC GEOLOGY
208
Bull.
Surv.,
Amer.
8,
1904.
(Many
Arkansas:
analyses.)
XXVII:
Trans.
Min. Engrs.,
Inst.
42,
1898.
9.
(S.
Branner,
W.
Ark.)
22d Ann. Kept., Ill: 687, 1902. (S. W.

11. Grimsley, Eng. and Min. Jour., LXXIlf 71,
California:
Ark.)
1901.
(Cement industry.) 12. Irelan, 8th Ann. Kept., State Mineralogist: 865 to 838, 1888; also 9th Ann. Kept: 309-311, 1889; 13th
Ann. Kept. Calif. State Mineralogist: 627, 1896; 12th Ann. Kept.:
(Cements.) Anon., Calif. State Min. Bureau, Bull. 38.
381, 1894.
U.
10. Taff,
S. Geol. Surv.,
Colorado: 12a. Eckel, U. S. Geol. Surv., Bull. 522, 1913.

13. Fla. Geol. Surv., 1st
Ann. Kept.:
Georgia: 14. Maynard,

15. Cummings, U. S. Geol. Surv.,
Ga. Geol. Surv., Bull. 27, 1912.

21st Ann. Kept., VI: 410, 1901.
Illinois:
17. Bleininger, Lines
Surv., Bull. 522, 1913.
Surv., Bull. 17, 1912.
Dept. Geol. and Nat.
Indiana:
Florida:
40, 1908.
18.
16. Eckel,
U.
S.
Geol.
and Layman, 111. Geol.

Blatchley, 25th Ann. Kept, Ind.
1900:
(Bedford limestone.)
323, 1901.
25th Ann. Kept. Ind. Dept. Geol. and Nat. Res., 1900:
20. Blatchley, Ibid.,
(Silver Creek hydraulic limestone.)
331, 1901.
28th Ann. Rept.: 211, 1903. (Lime industry.) 21. Blatchley and
Iowa:
(Marl deposits.)
Ashley, Ibid., 25th Ann. Rept.: 31, 1901.
Res.,
19. Siebenthal,
22.
Bain and Eckel,
la.
Geol.
XV:
Surv.,
XVII: 1907. (Tests of Iowa

(General.)
Williams, Ibid., XVII: 29, 1907.
23. Williams,
33.
la.
Beyer and
Kansas: 25. Haworth,
Kas. Geol. Surv., Ill: 31, 1898. 26. Adams and others, U. S. Geol.
27. Annual bulletins on
(lola Quadrangle.)
Surv., Bull. 238, 1904.
Mineral Resources, issued by Kansas Geological Survey. 28. Haworth
and Schrader, U. S. Geol. Surv., Bull. 260: 506,1905. (Independence
Geol.
Surv.,
24.
limes.)
Kentucky: 29. Kentucky Geol. Surv., New Series,

Quadrangle.)
Maine:
IV: 404. 30. Eckel, U. S. Geol. Surv., Bull. 243: 171.
31. Bastin, U. S. Geol. Surv., Bull. 285: 393, 1906.
(Knox County.)
Maryland: 32. Clark and others, Md. Geol. Surv., Rept. on Allegany Co.: 185, 1900. (Lime and cements.) 33. Martin, Md. Geol.
33a. Mathews and Grasty,
Surv., Rept. on Garrett Co.: 220, 1902.
Md. Geol. Surv., VIII: Pt, 3: 225, 1910.
Michigan: 34. Hale and
(Marl for Portland
others, Mich. Geol. Surv., VIII, Pt. 3, 1903.
1901.
Eng. and Min. Jour., LXXI: 662, 693, and 725,

36. Russell, U. S. Geol. Surv., 22d Ann.
limestones.)
Missis(Mich. Portland cement industry.)
629, 1902.
35. Lane,
cement.)
(Mich,
Rept., Ill:
37. Crider, Miss. Geol. Surv., Bull.
sippi:
Missouri:
New
9.
37o.
Jersey:
(N.
J.
38.
Buehler,
Mo.
Geol.
1,
Surv.,
Kummel, Ann. Rept. N.
Portland
cement industry.)
J.
39.
1907.
2d
(N. E. Miss.)
VI. 1907.
Ser.
State Geologist,
Kummel, N.
J.
1900:
Geol.
Ann. Rept., 1905: 173, 1906. (Limestones, Sussex and Warren

New York: 40. Bishop, 15th Ann. Rept. N. Y. State
counties.)
41. Nason, Rept, of N Y. State
(Erie Co.)
Geologist: 338, 1897.
42. Pohlman, Amer. Inst. Min.
(Ulster Co.)
Geologist, 1893: 375.
Surv.,
Trans. XVIII: 250, 1889.

(Cement rock at Buffalo.) 43.
Ries and Eckel, Bull. N. Y. State Museum, 44, 1901.
(N. Y. lime
Ohio: 44. Lord, Ohio Geol. Surv., VI: 671,
and cement industry.)
1888.
(Natural and artificial cements.) 45. Eno, Ohio Geol. Surv.,
Engrs.,
209
4th Series, Bull. 2, 1904. (Uses of cement.) 46. Bleininger, Ibid.,

Bull. 3, 1904.
(Manufacture of cement.) 47. Orton and Peppel, Ibid.,
Oklahoma: 47a Okla. Geol.
Bulls. 4 and 5, 1906.
(Limestones.)
Oregon: 476. Williams, Min. Res. Ore.,
Surv., Bull. 5: 114, 1911.
Pennsylvania: 48. Prime, Second Geol. Surv.
52, 1914.
I, No. 7:
Rep. DD: 59, 1878. 49. Clapp, U. S. Geol. Surv., Bull. 249,
(Limestones, S. W. Pa.) 50. Peck, Econ. Geol. III.: 37, 1908.
(Lehigh district.) 50a. Hice, Pa. Top. and Geol. Com., Rept. 9: 71,1913.
South Dakota: 51. S. Dak. Sch. of Mines, Bull. 8, 1908. (Black
Tennessee: 52. Eckel, U. S. Geol. Surv., Bull. 285: 374,
Hills.)
of Pa.,
1905.
1906.
States:
states.)
(Tenn.-Va.)
53. Eckel,
United
52a. Gordon, Res. Tenn., I, No. 2.
(Details on all
U.
Virginia:
54. Catlett,
U.
S.
Geol. Surv.,
Bull.
225:
457,
(Cement resources, Valley of Va.) 55. Bassler, Min. Res. of

55a. Bassler, Va. Geol. Surv., Bull.
Va., Lynchburg, 1907, p. 86.
Washington: 56. Landes, U. S. Geol. Surv., Bull. 285:
II-A, 1909.
1904.
West Virginia: 57. Grimsley, W. Va. Geol. Surv., Ill,

377, 1906.
Wisconsin: 58. Chamberlin, Geol. of Wis., II, Pt. 2: 395,
1905.
1873.
(Natural rock cement.) Buckley, Wis. Geol. and Nat. Hist.
Surv., Bull. 4: 255,
Bull. 315: 232, 1907.
1898.
(E.
Wyoming:
Wyo.)
59. Ball,
U.
S.'
Geol. Surv.,
CHAPTER
VI
SALINES AND ASSOCIATED SUBSTANCES
UNDER
salt,
the heading of salines are included the substances,
sodium sulphate, sodium carbonate, sodium and
borax,
potassium nitrate. They are all easily soluble substances, which

are either found dissolved in the waters of lakes, seas or oceans, or
may be present at times in the rocks or soils. As a result of the
leaching of the last-named by underground waters, they may be
brought to the surface and deposited there as an incrustation,

often found in arid regions; or they may be carried into bodies
of water, where they remain in solution until the waters by
evaporation leave them behind as residues. Either mode of
deposition would be characteristic of an arid climate.
The above outlines in general their manner of formation,
although there may be exceptions, as will be seen in subsequent
pages.
Bromine, calcium chloride, and iodine are also treated in this

two with sodium
chapter, because of the association of the first

chloride, and of the third with sodium nitrate.
From what has been

bodies of saline water
said above,
it
will
be readily seen that
not only vary in their degree of concentration, but also in the kind and relative amounts of the different saline substances which they contain in solution.
The analyses on
p.
may
211 will show this variation.
SALT
of Occurrence.
Types
Common
salt,
the chloride of sodium
a widely distributed mineral, being found: (1) in solu(NaCl),

tion in sea w ater or salt lakes; (2) as solid masses termed rock
is
salt;
(3)
as natural brine in cavities or pores of the rocks, from

salt springs or be tapped by wells; ard (4)
which it may exude as

in marshes and soils.
Although all four of these types of occurrence may serve as

commercial sources of salt, it is only the second that is of great
economic importance.
210
SALINES
AND ASSOCIATED SUBSTANCES
ANALYSES OF LAKE AND SEA WATERS
211
ECONOMIC GEOLOGY
212
saliferous
former
They sometimes
formations.
represent the
site
of
salt lakes.
Rock salt, which is the most important source

Salt.
commercial salt, occurs commonly in beds of variable thickness
and purity interbedded with sedimentary rocks, such as shales or
It is frequently associated with gypsum, and less
sandstones.
Rock
of
commonly with limestone, or easily soluble compounds of magnesia,

Less often, the rock salt is found in domelike
but not conformable with them. Rock
potash, and lime.
masses in
stratified rocks,
from a few inches up to as much as

Germany); and while found in all geoformations from the Cambrian to the Pleistocene, except
salt deposits
3600
vary
in thickness
feet (Sperenberg,
logical
the Cretaceous, the rock salt of the United States

formations older than the Upper Silurian.
is
not found in
One of the interesting problems

Rock Salt (l-7a).
been
to
a
correct
find
has
of geology
theory to account for the
Such
a
of
salt
deposits.
problem is not as simple as it
origin
it
at
first
for
must
explain (1) the formation
sight,
may appear
Origin of
of salt deposits of extraordinary thickness, (2) the association of

gypsum, either above or below the salt, and (3) the presence of
other minerals, which
may
or
may
not be saline ones.
generally believed that most deEvaporation Theory.

of
or
rock
and gypsum, have been formed
of
rock
salt
salt,
posits
It
is
of oceans and lakes, this process having

a
of periods from the Silurian to the
number
on
during
gone
by the evaporation
present.
If
a body of salt water
is
evaporated until precipitation begins,
the least soluble salts will generally separate out

most soluble ones do not precipitate until the last.
first,
while the
Assuming then a basin filled with sea water, similar in composition to that of the present oceans, the order of precipitation would be: (1) iron hydroxide; (2) calcium carbonate; (3)
calcium sulphate; (4) sodium chloride; and (5) easily soluble
compounds, such as sulphates and chlorides of potash and magnesia, etc., these being often of quite
This order of precipitation was
1849,
by
tests of
The
J. Usiglio,
who made an
complex composition.
demonstrated as early as
elaborate series of evaporation
Mediterranean water.
four following analyses, reduced to ionic form and to
1
Ann. chim. phys., 3d.
ser.,
XXVII:
92, 192, 1849.
SALINES
213
percentages of total solids, represent the composition of the

sea water evaporated to different densities. 1
ANALYSES OF MEDITERRANEAN WATER AND BITTERNS

CONSTITUENTS
ECONOMIC GEOLOGY
214
4.
Rock
5.
Anhydrite No. Ill (Pegmatite anhydrite)
6.
Red
7.
Younger rock
salt
....
Main
salt,
with about 400 annual rings of
averaging
12.
MgCl2 6H O) zone
(MgSO 4 H O)
Polyhalite (K2 SO 4 MgSO 4 2CaSO 4 2H 2 O)
13.
Older rock salt with about 3000 annual rings averaging
10. Carnallite (KC1,

11. Kieserite
m.
m.
m.
m.
18 m.
35 m.
245 m.
80
30-80
5-10
15-40
anhydrite, No. II
9. Salt clay,
5m.
10 m.
clay
polyhalite
8.
40 m.
zone
Nos. 11, 12, 13 have a combined thickness, ranging from 150 to perhaps
1000 meters. (Due perhaps to subsequent thickening.) The annual rings
of anhydrite form layers averaging 7 mm. thick, separating the_salt into sheets
of 8 or 9
14.
15.
mm.
Older anhydrite (I) and gypsum, averaging
Zechstein limestone or dolomite
100 m.
slates
16.
Copper
17.
Zechstein conglomerate
The lower members, beginning with anhydrite I and ending with the
form one depositional series. Above this, and separated
from it by a clay member, is a second series, which lacks the more soluble
carnallite zone,
salts.
Assuming then that the evaporation of a body of sea

graded series as shown above, we must in order to
it consider the following:
(1) The most soluble salts are
wanting; (2) salt and gypsum may occur singly; and (3)
salt and gypsum deposits exhibit great thickness.
may give a
water
apply
often
many
The absence
of the mother-liquor salts may be explained by

that
the
water never was sufficiently concentrated to
assuming
cause their precipitation, or if this did occur they may have been
redissolved, before a protective covering, such as a clay sediment,
was deposited on them.

It is not difficult to conceive that evaporation
went on
far
enough to deposit gypsum, and not enough to precipitate salt,

but it is more difficult to explain why salt was sometimes deposited,
without any gypsum under it, unless we assume that some of
the earlier oceans were of a different composition than existing
ones.
The most
difficult problem, however, is to explain the forvery thick deposits of salt between stratified rocks, on
the basis of simple evaporation of a body of water.
mation
of
SALINES
215
We
can easily understand the formation of a thin bed of salt

in this way, but the insufficiency of this
explanation
appears, when we find that the formation of 15 feet of gypsum
would require the evaporation of 35,000 feet of existing ocean
water, and since salt is more soluble, a much greater depth would
be required.
This theory, which seeks to explain the origin
Bar Theory.
(or
gypsum)
of salt deposits of great thickness, was first suggested by G.

1
It assumes
Bischof, and later elaborated by Ochsenius (l, 4).
a barrier partly shutting out the ocean water. Evaporation on

the inclosed area of the sea exceeds the supply of water from
Therefore the water
inflowing rivers and from the open ocean.
on the surface
bottom of the
becomes more dense and settles to the

basin, being prevented from escape into the open
of the sea
ocean by the barriers at the entrance. As the surface of the

bay is lowered by evaporation, ocean waters enter, furnishing a
If the barrier is complete, forming a
enter
may
only at times of high tide or storm.
will
so concentrate the solution in the
Eventually evaporation
as
to
cause
the
bay
precipitation of sodium chloride and other
constant supply of
salt.
bar, sea water
So long as these conditions lasted, salt would be precipitated, but beds of clayey material would be deposited wherever
fine-grained sediment was supplied from the land.
This theory has appealed to many, and the case of Karaboghaz Gulf on the eastern side of the Caspian Sea, is often quoted
salts.
as illustrative of the deposition of salts according to the hypothmentioned above. The Gulf referred to is connected with
esis
the sea by a shallow channel through which it is continually

supplied by water, the latter delivering a daily estimated load
of 350,000 tons of dissolved salts.
V and VI, p. 211, show the composition

and the gulf respectively.
Analyses
of the sea
of the waters
The Karaboghaz water contains 285 parts per million of salts,

gypsum will precipitate when the concentration is 202
while
It is
a sulphate chloride bittern, in which
replaces lime.
We find, then, that while some gypsum
parts per million.
magnesium
is
deposited around the margins, the bottom
nesium sulphate, which
in places
is
being estimated at 1,000,000,000 tons,

1
Allgemeine Chemische
u.
is
covered by mag-
7 feet thick, the total deposit
The
salinity,
although
Physikalische Geologic, II: 48, 1864.
ECONOMIC GEOLOGY
216
not yet sufficient to precipitate salt, but the water

sufficiently saline to prevent marine life, so that any animals
increasing,
is
is
carried into the gulf die.

Of more interest are the
Suez Bittern Lakes, which were

formerly a continuation of the present Gulf of Suez, and the
Red
Sea.
When
the gulf became silted up to such an extent that the

supply of water from the Red Sea just balanced the evaporation
from the surrounding surface of the Gulf, and the salinity was
of corresponding magnitude, salt began to deposit and continued
until some time after the complete separation from the Gulf
of Suez and transformation into the Bittern Lakes.
When the
Suez Canal was cut, a salt mass 13 km. long, 7 km. broad, and
averaging 8 meters in thickness was found. It showed parallel
layers separated by thin layers of earthy matter and gypsum.
The operation of the bar theory is probably restricted to
arid regions, where there will be little inflow of fresh water into
the bay, and where evaporation will be accelerated.

Grabau points out that: (1) the bay must be connected
with a large sea;
(2)
that there should be a contemporaneous

and (3) that the salt deposits
fossiliferous series in the sea;
themselves, as shown by Karaboghaz and Bittern Lakes, should

be fossiliferous. If these criteria fail, he believes that the deposit could not
have been formed by the evaporation of sea
water.
More
recently Branson (la) has suggested a modified bar

which
postulates overflow basins connected with a main
theory,
one, the precipitation of the salts taking place in the former.
This theory has been specially urged by WalDesert Theory.
who
the
saw
ther,
objections to the bar theory mentioned above.
According to the desert theory, extensive salt deposits might be

formed by the leaching of the salt from an older more or less
saliferous formation.
This salt might be contained in connate
waters or in the rocks. If brought to the surface either by evaporation or erosion, it may perhaps first form a crust there, and be
If in a drainless basin, it may
later removed by wind or rain.
accumulate in a body of water within the depression. As the

water evaporates, and leaves any of the salt on the drainage
slopes, it may still be washed down into the contracting sea or
lake, whose salinity gradually increases to such an extent that
the salt begins to deposit.
SALINES
Grabau
217
thinks that the Siluric salt of North America has

been derived from connate waters of the Niagara formation, of
which a vast amount has been eroded, for he says, " the fact
that all around the Salina area, the Upper Siluric strata rest on
Niagaran except where the continental deposits of Salina time
intervene, and the further fact that no
alents of the Salinan are known in
undoubted marine equivNorth America, greatly
strengthen the argument for the wholly continental origin of

these salt deposits."
Dtplh
......
Fo.
......
2000 dr
......
3000*
Figures representing the origin of dome structure by crystalline growth.

(After Harris, Econ. Geol. IV.)
FIG. 70.
Dome
Theory (Fig. 70).
some other
rock
in
ocoo
salt,
In Louisiana and Texas as well as
there are found great domelike masses of

accompanied at times by gypsum, limestone, and even
G. D. Harris (6) believes they have been formed as follocalities,
sulphur.
lows: Heated waters coming up through underlying formations
have become saturated with salt from deposits occurring in them.
These waters found a pathway in
fissures related to the differential
uplifting of the rocks in the Mississippi embayment, and marking

the position of anticlines. Cooling of the uprising solutions caused
them
It is thought that the

to deposit the salt in these fissures.
force exerted by the crystallizing salt was sufficient to lift up the
overlying Tertiary and Quaternary beds, as the accumulation
went on. 2
These cores of salt have been pushed up through Cretaceous, Eocene, and even Quaternary strata.
R. T. Hill likewise thought the salt domes due to deposition
by ascending solutions, but that the upraising of the surrounding
strata was caused by the hydrostatic pressure of the salt solu1
Principles of Stratigraphy, p. 376.
See
Day and
Becker, Wash. Acad. Sci. Proc., Vol. 7:
288, 1905.
ECONOMIC GEOLOGY
218
tions
and to
oil
rising
through the fractures
in the rocks.
On
the other hand, Hager and Veatch suggested laccolithic intrusions

as the cause of the uplift, and recently it is claimed that a hard
rock, possibly of igneous origin, has been struck by the drill
below one of these domes.

Distribution of Salt in the United States.
in a
number
FIG. 71.
Map
of states, as
Salt deposits are found
shown on the map,
Fig. 71,
but nearly
showing distribution of salt-producing areas in United States, compiled from various geological survey reports.
63 per cent of the production in 1914 came from two states, New
Most of the domestic production is obtained
either in the form of artificial brine obtained by forcing water
York and Michigan.
through wells to the salt, which is then brought up in solution, or else

as rock salt, raised through shafts from underground workings.
The range of geologic age of the United States deposits is shown
in the following table:
TABLE SHOWING GEOLOGIC DISTRIBUTION OF SALT

STATE
IN
THE UNITED STATES
PLATE
FIG.
1.
XXIV
Interior view of salt mine, Livonia,
N. Y.
Both roof and
pillar are
rock
salt.
FIG.
2.
Borax mine near Daggett, Cal.
(Photo, loaned by G. P. Merrill.)
(219)
ECONOMIC GEOLOGY
220
Salt was manufactured from brine springs at

New York (15).
Onondaga Lake as early as in 1788; but the presence of rock salt
beds was not suspected until 1878, when a bed seventy feet thick
was struck in drilling for petroleum in Wyoming County. Since
then the development of the salt industry has been so rapid that
some years New York has been one of the two leading salt-
for
producing
The
states.
salt occurs in lenticular
masses interbedded with
soft shales
of the Salina series (Fig. 72), which also carry gypsum deposits.
The outcrop of the formation coincides approximately with the
New York Central Railroad, but owing to its soluble

no
salt is found along the outcrops.
The beds dip southcharacter,
ward from 25 to 40 feet per mile, so that the depth of the salt beneath the surface increases in this direction.
line of the
At Ithaca, salt is struck at 2244 feet, and there are seven beds. The thickness of the individual beds varies, but the greatest known thickness is in a
well near Tully, where 325 feet of solid salt was bored through.
Salt has
also been struck by a deep boring in the oil field of southwestern New York
at a depth of
about 3000
obtained from
feet.
artificial brines,
Though most
New York product

mined by shafts."
of the
a small quantity
is
is
Salt in Michigan is obtained both from natural

Michigan (13).
and from brines obtained by dissolving rock salt, as in New
brines
York. The natural brines occur in the sandstones of the Mississippian, the most important locality being in the Saginaw Valley, where
the brines are found in the Napoleon or Upper Marshall sandstone.
They are remarkable for the large amount of bromine contained,

more than half the bromine produced in the United States being
obtained here. The vast beds of rock salt which occur in the Salina
(Monroe) are exploited along the Detroit and St. Clair rivers and at
Manistee and Ludington. The salt is dissolved by lake water
pumped down and then re-evaporated, and soda ash (sodium carbonate)
is
made from
the salt to a very great extent, by forced
reaction with calcium carbonate.
Ohio
Natural brines are obtained from the "Big Salt
(16).
"
(Mississippian) at Pomeroy, Meigs County, but the profit

in pumping them lies in the bromine and calcium chloride which
Sand
In northeastern Ohio the wells pierce a bed of rock

which is 148 feet thick and interbedded
with limestones and shales. The wells are about 1900 feet deep at
Cleveland and 2800 feet at Kenmore, Summit County.
they contain.
salt in the Salina (Silurian),
Private communications from Dr. A. C. Lane.
SALINES
221
222
The two
ECONOMIC GEOLOGY
following analyses are of interest, partly on account
The absence of sulphate in the first is
of their completeness.
noticeable.
ANALYSES OF OHIO BRIXES
SALINES
223
the Carboniferous; (3) in the Permian of south central Kansas as

beds of rock salt (Fig. 74). At the present time the rock salt is the
most important commercial source, being obtained in part as artificial brines and in part as rock salt.
The thickness of the salt
varies, the greatest aggregate thickness recorded in
324
The
feet.
any
well being
deposits thin out to the eastward, and the north and
Mii..
Geologic section from Arkansas City to Great Bend, Kas., showing
occurrence of rock salt.
(Kas. Geol. Surv., Min. Res. Butt., 1898.)
FIG. 74.
south limits are fairly well known, but the western boundary remains undefined. The absence of gypsum in close association with
the salt
horizon,
a significant fact, but farther south it is found at a lower

of the two is explained by a shifting sea
is
and the separation
bottom, during deposition.

Brine occurs in springs and wells in the
Louisiana (10, 11, 12).
Cretaceous area of northern Louisiana, but the most important source
of salt is in the extenTECHE OR
ATTAKAPAS COUNTRY
Showing. Location of the
AVERY SALT MINE
sive beds of rock salt
found in the southern

portion of the state.
These underlie a series
of low knolls, called the
Five Islands (Fig. 75),

and are covered by a
series of clay, sand,
and
gravel beds. The salt

occurs as great dome-
like
masses which
Harris thinks have been
pushed up into CretaTertiary, and

ceous,
Quaternary beds
FIG. 75.
,,
other
,,
Map showing location of Petite Anse and

..
.
|
salt islands,
Louisiana.
,,
(After Pomeroy.)
(p. 217).
on
Salt
j^
Grande
/-i
is
mined
r*A.4-r.
uote
or
ECONOMIC GEOLOGY
224
Weeks
Island and also on
Avery
Although the
Island.
The age of the
amount
salt
beds
is
rock salt present is

pre-Pleistocene.
in
one
case
revealing a thickness of 1756
evidently great, borings
feet of solid salt, these deposits yield but a small percentage of
of
the country's output.

In California the main supply of salt is obtained
an elaborate system of ponds, covering thousands of acres, having been built on San Francisco Bay. These are filled
at high tide, and the brine evaporated by solar heat, although artificial heat
A large deposit of salt was formerly worked
is used at some of the plants.
This is a depression 27 miles long, 3 to 9 miles wide, and
at Salton Lake.
Other Western States.
by evaporating
sea water
(8),
So-a. a.,
d
!***
FIG. 76.
*1
SACT
cc~*1.ri
a-..-,
dome salt occurrence, under Cedar Lick, La.

Harris, La. Geol. Sun., Bull. 7.)
Section illustrating
(After
its lowest point 280 feet below sea level.

The deposit is formed by evaporation of the lake waters, which are fed by saline springs from the surround-
at
The salt, which has accumulated to a depth of 6 inches, is

ing foothills.
gathered by scrapers. Salt is also found in marshes, springs, or wells in a
number of other localities in California (8).
In Idaho brine salt is obtained in Bear Lake and Bannock counties,
near the Wyoming line some also is produced in Churchill and Washoe
counties, Nevada, Torrance County, New Mexico, and from saline lakes
in several parts of Texas.
Rock salt has been found at several localities in
Texas, notably in Mitchell County, and under the oil beds at Beaumont,
;
but none is yet produced.

In Utah, some salt is obtained by evaporating the waters of Great Salt
Lake (21), and brines from several other localities. An enormous deposit
of pure salt is reported from the west side of the Utah desert, near the
Nevada
state line. 1
Throughout the Red Beds area of western Oklahama, and in parts of

eastern Oklahoma, there are numerous salt springs and seepages, but Ferguson is the only locality of importance where salt is made (18).
1
U.
S. Geol. Surv.,
Min. Res., 1908.
SALINES
225
The only salt deposits now being exploited

are those of southwest Ontario, where the material is
obtained from the Salina formation. There appear to be a num-
in
Canada
Canada
(27).
ber of beds of varying thickness, interstratified with dolomite

and shale. The average depth of the salt is over 1000 feet, and
increases gradually to the south.
In the other Canadian provinces salt springs are known to

many points, but no deposits of rock salt have been
found except at two points, viz., near McMurray, Alberta, and
occur at
at Kwinitza, B. C.
Other Foreign Deposits (12).

Rock salt deposits are widely distribmost important world's producers need be mentioned.
In England it is found in the Upper Triassic marls, the Cheshire district having two important deposits lying respectively from 120 to 210 feet,
and 240 to 300 feet, below the surface. Many large deposits are also found
in the Triassic as well as the Permian of Germany.
Those of Stassfurt,
The German deposits_may occur as lenses, beds
are specially well known.
or domes. France is another important producer, rock salt occurring as
flattened lenses in saline clays of the Lorraine Triassic, and in rocks of the
uted, but only the
same age
in the Pyrenees.
In Galicia the Miocene deposits of Wieliczka are among the most curious
The upper part of the mass consists of irregular bodies of salt
known.
with blocks of sandstone, limestone and granite in saline clays, while below
Russia contains
it is stratified salt associated with clay and anhydrite.
abundant supplies in the southeastern and southern part of the country.

Of the Asiatic deposits the most important, perhaps, are those lying along
the Salt Range of northwestern Punjab, where the beds, underlying gypsum,
have been much disturbed by tilling and folding.
Analyses
of salt.
ANALYSES OF ROCK SALT FROM VARIOUS LOCALITIES
ECONOMIC GEOLOGY
226
ANALYSES OF SOLID MATTER OF BRINES FROM VARIOUS LOCALITIES
LOCALITY
SALINES
PRODUCTION OF SALT BY STATES FROM
Cm
19'-0
TO 1914, IN BARRELS
227
ECONOMIC GEOLOGY
228
valued at $5,229, while the imports for the year 1913 were
144,446 tons, valued at $565,283.
PRODUCTION OF SALT IN PRINCIPAL COUNTRIES OF THE WORLD
COUNTRY
SALINES
Canada:
Pt.
26.
I:
Bowen, Ont. Bur. Mines, XX,

11-8.
(Ont.)
Kept. 325, 1915.
27. Cole,
(General.)
Can.
pt. I:
Dept.
229
247, 1911, also
XIV,
Mines Branch,
Mines,
BROMINE
Sources.
Bromine occurs
in
nature
combined with some
metals, as in the minerals Embolite,
Ag (Cl, Br), Bromyrite (Ag Br),

and lodobromite (2 Ag Cl, 2 Ag Br, Ag I), which theoretically contain 25, 42.6, and 17.8 per cent respectively of bromine.
None of
these are commercial sources. Sea water contains about .06 gram
per liter, and at Stassfurt, Germany, the mother liquor obtained
from salt refining contains from 15 to 35 per cent bromine.
In the United States bromine is extracted from natural brines
found at several geological horizons, but not all rock brines contain
it, some, as those of New York State, being very low in it.
At the present time Ohio, West Virginia, Pennsylvania, and
Michigan brines are used, the
first
bromine having been manufac-
tured in 1846 at Freeport, Pennsylvania.
At Pomeroy and Syracuse, Meigs County, Ohio, and at Hartford

and Mason, Mason County, West Virginia, it is obtained as a byproduct of the salt industry, the brine coming from the Pottsville
horizon (Big Salt Sand).
A plant has been operated also at Pittsburg, Pennsylvania, obThat
taining the bromine from brines in the Pocono sandstone.
manufactured in Michigan comes from the Marshall sandstone of

the Lower Carboniferous, the brine containing from
bromine.
.1
to .3 per cent
Uses.
Bromine is used for making bromides of potash, soda,
and ammonia, for medicinal purposes and photographic reagents.
A small amount is employed in the preparation of coal-tar colors
known as Eosine and Hoffman's Blue. As a chemical reagent, it
is utilized for precipitating manganese from acetic acid solutions,
for the conversion of arsenious into arsenic acid, etc.
It
may
also
be used as a disinfectant when dissolved in water, and has been
employed
in gold extraction.
PRODUCTION OF BROMINE IN UNITED STATES

YEAR
ECONOMIC GEOLOGY
230
REFERENCES ON BROMINE
1.
Merrill, U. S. Geol. Surv.,

Indus., XVI 123.
Min. Res. 1904
1029, 1905.
2.
Lane, Min.
CALCIUM CHLORIDE
A considerable quantity of calcium chloride is obtained from

natural brines in connection with the salt and bromine industry
of Michigan, Ohio, and West Virginia.
The figures of production since 1909 are given below, but these do not include the
calcium chloride obtained in connection with the manufacture
of soda, for, in that case,
it is
not an original constituent of the
brine.
The following are partial analyses of brines supplying calcium

chloride
:
SALINES
231
SODIUM SULPHATE
The hydrous sulphate, mirabilite
Occurrence and Distribution.
Glauber salt (Na^SC^ + 10H 2O), is a white saline material,
which is collected on or near the surface of some alkaline marshes in
It may also be extensively deposited in some saline
desert regions.
or
and being affected

the
season
of
the
for
since
it is much more
by
year;
soluble in warm than in cold water, the difference in temperature
between summer and winter may cause its separation and re-solulakes, its precipitation preceding that of salt,
more
or less
tion
The phenomenon has been noticed in Great Salt Lake

Exposure to warm, dry air causes the mirabilite to lose its
(5).
(4).
water and change to thenardite.
No
production of sodium sulphate
States Geological Survey.
It is
is
known to
recorded by the United

occur at several localities
(3), and some of the deposits at least owe their

the
of sediments.
to
The deposit, which may be
leaching
origin
as much as 15 feet thick, consists chiefly of mirabilite, epsomite,
in
Wyoming
natrona, and halite (7). Deposits of some extent have also

been noted in the lowest portion of the Carriso Plain, along the
northeast boundary of San Luis Obispo County, California (6).
In this lake, which remains practically dry, except in very wet

seasons, there have been deposited a series of saline beds, whose
The salt has been derived
chief constituent is sodium sulphate.
from the leaching

There
is
little
and
of soft beds of conglomerate, sandstone,
shale in the surrounding
hills.
present
demand
for
"
sodium sulphate or
salt
used in glass making, ultramarine manufacture,

dyeing and coloring, as well as to some extent in medicine (Glau-
cake."
It
is
ber's salt).
REFERENCES ON SODIUM SULPHATE

1.
Attfield, Jour. Soc.
Ill:
651, 1895.
Chem.
3.
Ind., Jan. 31, 1895.
2.
Knight, Wyo. Agric. Exper.
Knight, Min. Indus.,

Sta., Bull. 14,
1893.
5. Clarke, U. S.
Gilbert, TJ. S. Geol. Surv., Mon. I: 253, 1890.
6. Arnold and JohnGeol. Surv., Bull. 616: 233, 1916.
(General.)
7. Schultz, U. S.
(Calif.)
son, U. S. Geol. Surv., Bull. 380, 1909.
Geol. Surv., Bull. 430: 570, 1914.
(Wyo.) 8. Gale, Ibid., Bull.
4.
540^
428, 1914.
(Calif.)
ECONOMIC GEOLOGY
232
SODIUM CARBONATE
Sodium carbonate, or natural soda, is obtained by the evaporation of the waters of alkali lakes, or is found as a deposit on or near
the surface of alkaline marshes in arid regions. It is usually a
mixture of sodium carbonate and bicarbonate in varying proportions, as well as impurities such as sodium chloride, sodium sulphate,
borax, and sodium nitrate.
Sodium carbonate has been obtained from Owens Lake in CaliAn analysis of the waters by Chatard yielded: SiO 2 .220;
Fe2O3 Al 2 a .038; CaC0 3 .055; MgCO8 .479; KC1, 3.137; NaCl,
fornia.
29.415;
soda
is
Na S0
CO
NaHCO
3
11.080; Na2
26.963;
purified by fractional crystallization.
4,
to occur in Oregon
The
known
5.725.
3,
Soda
is
also
and Nevada.
REFERENCES ON SODIUM CARBONATE

1.
2. Chatard, U. S.
Bailey, Calif. State Min. Bur., Bull. 24 95, 1902.
3. Russell, U. S. Geol.
Geol. Surv., Bull. 60 27, 1888.
(Analyses.)
4. Clarke, U. S. Geol. Surv., Bull. 616:
Surv., Mon. XI: 73, 1885.
:
237, 1916.
SODA NITER
Soda
when
(NaNOs, with 63.5 per cent Ôs

found in San Bernardino and Inyo counties, Cali-
niter, or Chile saltpeter
pure),
is
fornia, along the shore lines
in
Eocene times
(1).
marking the boundary of Death Valley

rounded hills of Eocene
It occurs in peculiar
found as a layer near the surface or distributed

Very little soda niter is obtained from this
source, and the main supply of this country continues to come from
Chile, where extensive deposits are found in the desert region west
of Iquique.
There the niter (caliche} forms a bed 6 to 12 feet thick,
clay, the niter being
through the clay.
under a cap of conglomerate
(costra) 1 to 18 feet thick.
The
origin
and has caused considerable discussion.

One theory quite generally accepted is that the niter was
formed primarily by the slow oxidation in air of guano or other
of this deposit
is
interesting,
nitrogenous organic matter in contact with alkali a second theory

refers its origin to the oxidation of organic materials and ammonia,
;
by microscopic organisms known
as nitrifying germs.
REFERENCES ON SODA NITER

1.
State Min. Bur., Bull. 24: 139, 1902. 2. Clarke, U. S.

Bailey,
Geol. Surv., Bull. 616:
253, 1916.
(Chemistry, analyses, origin.)
Geol. XVIII:
3. Penrose, Jour.
1910.
4. Gale, U. S.
1,
(Chile.)
Calif.
Surv., Bull. 523, 1912.

Miller, Econ. Geol. XI, 1916.
Geol.
The term
niter,
(Nitrate deposits.)
when used
5.
Singewald and
alone, refers to potash niter.
SALINES
233
BORATES
Various compounds of boron are known in nature. When
contained in complex borosilicates the material is of no commercial value as a source of borax.
It may also be present in volcanic emanations and hot spring waters, but while in the United
States these are of no importance, in Tuscany, Italy, the gases,
steam and hot waters are of value, the waters being caught in
basins to evaporate, while the borax crystallizes out.
In the United States the chief minerals containing boron

^26467, 10 HÔ; coleman2 0; ulexite, CaNaB 5 Og, 8 H2O;
ite, Ca2B 6 On, 5
boracite, 2
are borax, tincal, or sodium biborate,
MgsBgOis, MgCb. These minerals are found usually as incrustations in alkaline marshes, in lake waters of arid regions, or as
massive deposits.
Deposits of borax (Fig. 77)
have up to the present time been discovered only in California
Borax was originally
2, 5), Nevada, and Oregon
(1,
(3, 8).
obtained by evaporation from the waters of Clear Lake, 1 north of
San Francisco, being produced in commercial quantities in 1864,
and the solution was enriched by crystalline borax obtained from
the marshes surrounding the lake. This and other lakes of
California were worked until the discovery of large deposits of
nearly pure borax in alkaline marshes of eastern California and
western Nevada in the early seventies, the mineral most characteristic
of
these .being ulexite.
Still
later there
came the
de-
velopment north of Daggett, Calif., of bedded muds and clays

with low grade borates of lime, but even these had to give way to
the subsequently developed colemanite deposits.
Colemanite was first discovered in Death Valley, Inyo County,
Calif., in 1882, and in the following year 12 miles north of Daggett,
San Bernardino County,
Calif., this
being followed by
similar formations in the
discovery at many places

general regions where the marsh and
in
its
same
mud borax had been worked.

to as a bedded deposit,
referred
has
been
which
colemanite,
between sands and clays, was supposed by Campbell to have been
deposited in a series of Tertiary lakes (2), but the beds are in
many instances tilted, due to violent crustal movements, and
The
analysis of the solids of hot spring from sulphur bank on margin of Clear
4
7.88;
Cl, 16.49; I, .03; CO 2 21.96; B 4 O7 25.61; Na, 24.99;
(U. S. Geol. Surv., Bull. 330: 154.)
.40; SiO 2 2.64.
An
Lake yielded
A12 O3
NH
ECONOMIC GEOLOGY
234
LOS
JTXNENTURAX
*
A
QELES
SAN BERNARDINO
LEGEND
^ Colemanite
Locality
Marsh or dry lake deposits
A Borate waters
60
Fie= 77.
Map
100
showing borax deposits in the United States.

U. S. Geol. Sun., Min. Res., 1913,)
(After Yale and Gale>
SALINES
235
sedimentation was supposed to have been interrupted at intervals.
of the deposits in Ventura County, Calif.,

the
following general section:
gives
more recent study
by Gale
(3a),
Shale and some sandstone
300 feet
Basaltic lava flows, with intercalated lenses of

600
shale and limestone
600
Shale
Conglomerate, bowlders, or cobbles of light

600
granitic rock cemented
"
"
"
Other sedimentary rocks below.
The
and
beds, which are believed to be of Miocene age, are folded

faulted, and the most valuable borate deposits are included
FIG. 78.
Cross section of Furnace Canon,
Amer.
Inst.
Min.
Calif.,
borate deposits.
(After Keyes,
Engrs., 1909.)
and limestone found within the basalt,

be found in the shales above and below the
in the layers of shale
though some
may
latter.
in somewhat irregular masses, lacking a

and associated with travertine-like limestone.
vein-like character is also present, and there is a
The colemanite
is
stratified structure,
Selenite of
practical absence of any other salines.

Gale does not therefore believe the colemanite to
have been
precipitated in lake basins, but suggests that emanations of

boric acid both contemporaneous with, and, possibly, subsequent
to the basalt extrusion, attacked the limestone, replacing carbonic
acid with boric acid, thus forming the colemanite.
The material mined showed varying degrees of purity ranging

from 20-25 per cent IÔs, to nearly 40 per cent as shipped.
In this connection it is interesting to refer to an occurrence of
ECONOMIC GEOLOGY
236
the boron mineral pandermite, found in layers and stocks in beds

of gypsum, in Asia Minor, and to which a fumarolic origin has been
assigned.
The reduction of colemanite to borax and boric acid is accomplished by reaction with sodium carbonate, forming the soluble
borax, which is crystallized in vats.
In 1913, small quantities only were produced in Ventura County,
the supply coming mainly from a few mines in Inyo and Los
Angeles counties, California.
The borax-bearing minerals
Uses.
manufacture of borax and boracic

trial
are utilized chiefly for the

Borax is used in indus-
acid.
chemistry, in medicine, and as a laboratory reagent.
It is
employed in the assaying of gold and silver ores, in soldering

brass, and welding metals.
Boric acid is used in the manufacture of borax, in colored glazes
for decorating iron, steel, and metallic objects, in enamels and glazes
for pottery, in making flint glass, as an antiseptic, and as a preservative for food.
Chromium borate makes a green pigment used in
calico printing, and manganese borate is sometimes employed as a
drier in paints and oils.
Borax is also extensively used in numeralso
ous cosmetics.
The chief refiners are the Pacific Coast Borax Company with
works at Bayonne, New Jersey, and Alameda, California, and the
Sterling Borax Company of San Francisco, California.
Production of Borax.
The California colemanite deposits form
the main source of domestic supply, the output being derived from
the counties of Los Angeles, Inyo, and Ventura. The marsh
deposits of Nevada are no longer productive.
The production of borax in California from 1909 to 1914
was as follows, the values being based on the boric-acid
content
of
the
corresponding number of crude tons of
manite or borate of lime:
PRODUCTION OF BORAX IN CALIFORNIA

YEAR
cole-
SALINES
237
IMPORTS FOR CONSUMPTION OF BORAX AND BORATES INTO THE UNITED

STATES, 1910-1914, IN
POUNDS
ECONOMIC GEOLOGY
238
Pennsylvania ones carrying .5587 gram of

calcium iodide per liter.
At present the entire production of iodine comes from two
sources, viz., the ashes of sea weeds and the niter deposits of Chile.
oil-well waters, certain
REFERENCES ON IODINE
1.
Clarke, U. S. Geol. Surv., Bull. 616: 17, 119, 183, 1916.

ences.)
2.
Min. Indus.,
XVI
(Many
refer-
582, 1907..
POTASH
The occurrence
of this substance
is
referred to in this chapter,
because the world's main source of supply at the present time is

obtained from deposits of salines. The element potassium is,
however, a constituent of other minerals not to be classed as

salines, but for purposes of convenience they will be discussed
here.
Practically all the potash salts of mineral origin consumed in

North American industries are at present imported from abroad,
In 1913 the U. S. imports of potash
chiefly from Germany.
salts, not
including kainit and manure salts, amounted to
612,514,916 pounds, valued at $10,805,720.

were naturally smaller, due to the war.
Potash in Saline Deposits.

salt
section
The 1914 imports

of the
remarkable
deposits at Stassfurt, Prussia, has been given on p. 213.
had been a producer of salt for some time, the

and value of the potash and magnesia salts overlying
the rock salt was not fully realized until 1860. Since then the
potash industry has assumed large proportions, and in addition
While
this locality
true nature
known at Hanover,
South Harz mountain, and West Alsatia. Mines are also operating near Hamburg and Bremen, while lean deposits with poor
to those at Stassfurt, other deposits are
cover are said to occur in Holland. 1

Small, partly developed deposits exist near Kaluz in Galicia,
and about 1912 (others were discovered near Sauria, Spain 2
These last may in time become important producers.
The United States has not only been dependent on Germany,
but has taken a large portion of its output, and its dependence
on that country became keenly recognized during the GermanAmerican potash war of 1909-10.
1
MacDowell, C. H., Amer.
Inst. Geol.
Inst. Min. Engrs., Trans., LI: 424, 1916.

de Espana, Bol. 34: 173, 1914.
SALINES
239
This led to a search for potash in the United States, attention being first turned to the saline deposits, of which there are
several possible sources.
A study of these shows that

Brines and Bitterns (6, 7).
none of the artificial brines, natural brines, or rock-salt deposits
of many examined contain sufficient potash salts to render them
The following table gives
of commercial value for this purpose.
the composition of some.
COMPOSITION OF SOLID MATTER IN BRINES FROM SALT WELLS

Parts per Million
ECONOMIC GEOLOGY
240
PROFILE OF THE FORMER
OWENS DRAINAGE SYSTEM
117
FIG. 79.
Map
showing Owens and neighboring lakes of California.

Gale, U. S. Geol.
Sun.
Bull. 530, 1915.)
(After
SALINES
241
forma; and Lake Le Conte in the Imperial Valley of the Colorado

Desert, California.
If
is
now such a
large
body
that the salts would be
of water evaporated, the assumption

as a crust on the basin floor or be
left
absorbed by the sands and clays underlying it. Another possibility is that residual brines may be found in the sands beneath
the basin floor.
Attractive as this theory apparently is on first thought, a carestudy of the subject tends to the belief that the outlook
ful
for finding potash or other salts under such conditions is not very
promising, so that most of the saline crusts, dry-lake areas,
playas of the desert region offer little induceas a source of potash. Two cases may, however, be mentioned.
salt flats, sinks or
ment
In the evaporation of a natural saline

both soda and potash, the latter would normally remain in solution much longer, and hence become concentrated in the residual brine, after most of the sodium chloride
Searles Lake, Calif, (s).
solution, containing
crystallized out, and theoretically we might expect to find

these potash-enriched brines in the sediments underlying former
lake basins.
had
The only important
case of this sort thus far discovered
is
that
Lake (Fig. 79). This lake, so-called, which is known

also as Borax Flat, is a dry-lake basin of the ordinary type,
occupying a depression which could be filled to a depth of 640
feet above the present salt flat before it would overflow into the
Panamint Valley to the south and east. This it evidently did in
of Searles
the past, and, moreover, the water that contributed to this former
high level was the overflow from Owens Lake.
At the present day we find the bottom of this desert basin

covered by a great sheet of solid white salts, unique in the variety
of its saline minerals.
This forms a central area of firm, crusted
salt,
covering about 11 square miles, surrounded by a zone of
salt-incrusted
vial material
mud and sand, composed of salts and mixed alluwashed into the basin from the surrounding valley
slopes.
The
salt of
thickness,
the central area
and
it
consists of
is
"
said to vary from 60-100 feet in

a consolidated mass crystallized
from an evaporating mother-liquor brine in which the salts are

still immersed, evaporation being about balanced by the influx
of ground water from the hill slopes."
ECONOMIC GEOLOGY
242
Analyses of the brine from

SiO 2
in the ignited residue:
K,
33.19;
works
6.22;
C0 3
7.11;
six wells
,
.02;
SO 4
for treating the brine
gave the following averages

Mg, 0; Ca, 0; Na,
As, .06;
12.76;
was being
B O7
4
Cl, 36.39;
built in 1914,
2.45.
which was
expected to handle 20,000 gallons of brine, turning out daily:

Borax, 225 tons; soda ash, 508 tons; salt, 1507 tons; sodium
sulphate, 593 tons; and potassium chloride, 489 tons.
Assuming that soluble potash
Deep Drilling (9-13).
salts
might be found in old lake bottoms, segregated as layers in such,

or in mother liquors of high concentration, attempts have been
made to discover these by drilling. Holes were put down by the
United States Geological Survey near Fallen, Nevada, and in
the Columbus Marsh, near Coaldale, Nevada. At the latter
place samples taken from 20-foot sections, averaged 5.96 per cent
water-soluble salts in the dried material, of which nearly one-third
is potassium
chloride, but the practical value of such saline
muds
is
considered problematical.
In bore holes in Railroad Valley, Nye County, Nevada, one of

the wells encountered considerable quantities of gaylussite
(Na 2 C0 3 -CaC03-5H 2 0) but no potash.

Sources of Potash, not Saline Deposits
This mineral, which has the formula
Alunite.
4SOs-6H20, has been regarded
as
among
future possibilities,
provided a sufficient quantity exists and a proper method of

extraction can be employed.
Several other localities have been recorded, as follows: 1. At
Marysvale, Utah (l). 2. In San Cristobal quadrangle, Colo. (2),

where there are several areas of alunitized granite, consisting
of quartz, pyrite and alunite, the latter in some cases forming
29 per cent of the rock.
Bovard, Nev.
(4).
The
3.
last
Near Patagonia, Ariz.

two are probably not
(3);
of
and
4, at
commercial
value.
Potash is an abundant constitIgneous Rocks. (14-17).

uent of some igneous rocks, in such minerals as orthoclase and
leucite, but the extraction of potash from these has not yet
been worked out on a commercial scale; moreover, it is doubtful
whether
it
could compete successfully with that obtained from
salines.
The
possibility of
working feldspar dikes or veins for this
SALINES
243
purpose has also been suggested, but the total available quantity
from this source would not be large.
It has also been suggested that the vast quantities of tailings
derived from the concentration of the monzonite and other
disseminated copper-bearing rocks
may some day serve
as a source
of potash (18).
The suggestion has been made that since potash volathe burning of Portland cement, it may be caught while passing
up the stack along with the dust which is precipitated by special means,
Other Sources.
tilizes in
such as an electrical treater.
The
extraction of potash from the kelp (18,
19) deposits
along the Pacific
coast has also been suggested.
REFERENCES ON POTASH
(Marysvale,
Loughlin, U. S. Geol. Surv., Bull. 620-K, 1915.
2. Larsen, Ibid., Bull. 530: 179, 1913.
(San Cristobal, Colo.)
3. Schrader, Ibid.., Bull. 540: 347,1914.
(Patagonia, Ariz.) 4. Schrader,
Alunite:
1.
Utah.)
Ibid., Bull. 540: 351, 1914.
(Bovard, Nev.) 5. Waggaman, U. S. Dept.

5a. Clapp, Econ. Geol., X: 70, 1915.
Brines: 6. Phalen, U. S. Geol. Surv., Bull.
Agric., Bur. Soils, Circ. 70, 1912.

(Brit. Col.
Soda
alunite.)
7. Turrentine, U. S. Dept. Agric., Bur. Soils, Bull.

313, 1913.
(Potash in salines.) 7a. Udden, Bull. Univ. Tex., No. 17,
94, 1913.
Arid Region Saline Deposits: 8. Dolbear,
1915.
(Tex. Permian.)
530:
Eng. and Min. Jour., XCV: 259, 1913. (Searles Lake.) 9. Dole,
U. S. Geol. Surv., Bull. 530: 330, 1913. (Silver Peak Marsh, Nev.)
10. Free, U. S. Dept. Agric., Bur. Soils, Circ. 61, 1912.
(Otero Basin,
N. Mex.) 11. Gale, U. S. Geol. Surv., Bull. 530: 295, 1913. (Desert
Basin Region). Also Bull. 540: 339, 1914, p. 407 (Death Valley) and
12. Hicks, U. S. Geol. Surv., Prof.
p. 422 (Columbus Marsh, Nev.).
Pap. 95, 1915. (Columbus Marsh, Nev.) 13. Young, U. S. Dept.
Silicates: 14. Cushman and Coggeshall, 8th Internat.
Agric. Bull. 61.
Congr. App. Chem., V: 33, 1912. 15. Herstein, Jour. Ind. and Eng.
Chem., Ill, 1911. (Feldspar.) 16. Ross, U. S. Dept. Agric., Bur.
17. Schultz, U. S. Geol. Surv., Bull. 512, 1912.
Soils, Circ. 71, 1912.
18. Butler, U. S. Geol. Surv., Bull. 620-J, 1915.
(Leucite Hills, Wyo.)
(Tailings from copper ores.)
Kelp: 18. Cameron, Frank. Inst. Jour.
CLXXVI: 347, 1913. 19. Merz and Lindemuth, Jour. Ind. and Eng.
Chem., V: 729, 1913.
CHAPTER
VII
GYPSUM
Gypsum (1,4), the hydrous sulProperties and Occurrence.
lime
occurs
most frequently in sedimenof
4
2
(CaS0
0),
phate
,
2H
tary rocks, interbedded with shales, sandstones,
and often more or
less closely associated
with rock
and limestones,
salt.
It is also
found as surface deposits mixed with clay (gypsite) (11), or in the

form of sand (5 Ariz.). The first two types are the most imporIt also occurs as efflorescent deposits, periodic
tant commercially.
lake deposits, in lumps and plates scattered through clays or shales,
in veins, and in limited quantities in volcanic regions, especially in
When occurring in bedded deposits (PI. XXV, Fig. 2).

(4).
often massive, of crystalline texture or earthy appearance, and
of variable color, although most commonly white and gray.
lavas
it is
Transparent, colorless forms,
known
as selenite, are found as veins or
crystals in the massive gypsum, or as plates and crystals in many clays,

This variety by itself never forms deposits of comshales, and limestones.
mercial importance, although selenite scales are sometimes plentifully

scattered through the purer varieties.
Alabaster is a pure white, finegrained, massive variety, which is sometimes used for ornamental work.
Gypsum when pure contains 46.6 per cent sulphur trioxide, 32.5
per cent lime, and 20.9 per cent water. It has a specific gravity of
It is therefore sufficiently soft to be
2.3, and a hardness of 1.5 to 2.
with a knife or even by the thumb nail.
from gypsum chemically in the absence of water,
Anhydrite
but changes to it on exposure to the air and moisture. In some cases
easily scratched
differs
it
may have
been derived from gypsum.
When
present,
it
may
occur as veinlets, beds or masses in the gypsum deposit; indeed, its

irregularity of occurrence is at times puzzling (PL XXV, Fig. 1).
Anhydrite contains 41.2

oxide.
As
if
it is
p"er
cent lime, 58.8 per cent sulphur triand its hardness 3 to 3.5.
Its specific gravity is 2.8 to 2.9
of
no commercial value,
it
may
cause trouble in quarrying,
present in large quantities.
Anhydrite has not usually been regarded as very abundant in

gypsum deposits of the United States. It is not uncommon
the
in the Virginia mines,
and Lane notes

244
its
occurrence in the deeper-
PLATE
XXV
View in a Nova Scotia gypsum quarry, showing large mass of anhydrite.

1.
The anhydrite forms the buttress on right of quarry face, and is not removed.
Good gypsum occurs on either side of it. (H. Ries, photo.)
FIG.
FIG
2.
Gypsum
quarry, Linden,
Y.
(Photo, loaned by
D. H. Newland.}
(245)
ECONOMIC GEOLOGY
246
gypsum series. It is also found with

Texas and Louisiana salt deposits. Some
extensive beds also occur in Oklahoma and a large mass has been
found in Lyon County, Nevada. Scattered irregular masses
and beds are abundant in some of the New Brunswick and Nova
lying parts of the Michigan
gypsum on top
Scotia
gypsum
Anhydrite
of the
areas.
be overlooked because of
may
and limestone, but although closely similar

be distinguished by the following tests (23.)..
to
Monoclinic.
Cleavage, perfect in one direction.
Cleavage, pseudo-cubic.
gr.,
about
2.9.
Hardness, 3-3J.
Fragments are square or rectangular,
with parallel extinction.
Soluble with difficulty in dilute hydrochloric acid.
Little or
easily
Gypsum
Anhydrite
Orthorhombic.
Sp.
resemblance to gypsum
its
gypsum, the two can
no water
Sp. gr., about 2.3.

c
Hardness, 1^ to l\.
Fragments are platy with oblique

extinction.
Easily soluble in dilute hydrochloric

acid.
in closed tube.
Abundant water
(20.97c)
closed
tube.
Double refraction rather strong.
Double refraction rather weak.
Clay is probably the commonest

Impurities in Gypsum.
impurity, and occurs either uniformly distributed through the
gypsum, giving it an earthy appearance and gray or brown color,
or else
it
may
be in layers.
Lime carbonate
is
often present,
though rarely in large amounts, although at times the gypsum

is interbedded with layers of limestone.
Magnesia, silica and
iron oxide may also be present, though not usually in large
amounts.
Owing to its solubility, massive gypsum sometimes contain
sink holes and underground solution channels, that not only
permit surface dirt to \vash into the deposit, but interfere at times
with the mining.
Gypsum is widely distributed

Origin of Gypsum (4,126,28).
both geographically and geologically, being found in various
horizons from the Silurian to the Recent. Most beds of this
substance have no doubt been formed by the evaporation of
salt water either in inland seas or else in arms of the ocean, the
process of precipitation having been discussed in the chapter on
As gypsum separates from sea water after 37 per cent of
Salt.
the water is evaporated, while salt precipitates only after 93 per
GYSPUM
247
cent has been removed,
it is evident that
gypsum beds may be
deposited without salt. This may also explain why gypsum is
more widely distributed than salt; and the fact that the percent-
age of gypsum in salt water is much less than that of salt probably
accounts for its usual occurrence in the thinner deposits.
Thin beds of gypsum may be formed by water percolating
through gypsum-bearing beds, and subsequently depositing the

gypsum so dissolved, by evaporation on the surface; or again,
crusts may accumulate from the drying up of the gypsiferous
waters of playas or temporary lakes.
Gypsum may also be formed by the decomposition of sulphides,
such as pyrite, and the action of the sulphuric acid thus liberated
on lime carbonate. Small quantities are formed in volcanic
regions through the action of sulphuric vapors on the lime of
volcanic tuffs or other rocks (4)
.
The
conditions under which anhydrite forms do not appear to

be thoroughly understood. According to Van 't Hoff and Weigert,
anhydrite forms from gypsum in sodium chloride solutions at

30 C., while in sea water the transformation takes place at 25 C.
Lane (12) believes that all calcium sul(Quoted by Clarke, 4).
phate precipitated at a greater depth than 500 feet is really anhydrite rather than gypsum. Indeed, some believe that perhaps
much of the gypsum now found was originally anhydrite.
Vater has pointed out that at ordinary, temperatures calcium
sulphate separates from a saturated salt solution as gypsum. The
temperatures noted above are not likely to be found in sea water,
although the Persian Gulf (la) has a mean temperature of 24 C.
owing to its shallowness, and Grabau suggests that if in such a
warmed body of water the deeper layers had become a con-
the successive influxes of calcium sulphate,

waters
during the rainy period would, on passing
by
brine
these
layers, be deposited directly as anhydrite,
through
in alternating layers with the salts.
centrated
brine,
brought in
the change of gypsum to anhydrite was brought about by

penetrating surface waters, it might account for the irregularity
That such a
of occurrence of the anhydrite in the gypsum.
If
transformation
may
extend to a considerable depth
is
shown by
the deposits at Bex, Switzerland (4), where the alteration has

reached a thickness of 60 to 100 feet.
But if the anhydrite represents the original mineral, then its

change to gypsum must be accompanied by increase of volume
ECONOMIC GEOLOGY
248
find a shattering or deformation of the surrounding beds, a condition actually found in some
in the mass,
and one might expect to
of the Paleozoic
gypsum
bearing-strata.
Another suggestion is that originally precipitated gypsum (28)

change to anhydrite when buried to depths of 1500 feet or
more. It is more than probable that in some cases gypsum has
been the original mineral, and in others anhydrite, especially if
Where the two are irregularly associated
either occurs ajone.
or mixed, the one may be derived from the other, but where
they occur in separate beds with sharp and even lines of separa-
may
tion,
both
FIG. 80.
may
Map
be original.
showing gypsum-producing
Adams, U.
United States.
(After
dirt, is an earthy or sandy variety of

surface
a
forming
deposit in Kansas (ll), and other
Gypsite,
gypsum
localities of the
S. Geol. Sure., Bull. 223.)
or
gypsum
(20, 24), which in spite of its impure appearance,

in
calcium sulphate. It is believed to be a deposit
run
high
may
either in the soil or in shallow lakes supplied by springs whose
water has dissolved the calcium sulphate from gypsum beds or
other rocks. During its precipitation by the second method,
its impure character is caused by its. becoming mixed with clay
western states
or sand
washed
1
in
from the land.
Grabau and
Sherzer, Mich. Geol.
and
Biol. Surv.,
Pub.
2.
GYSPUM
249
Distribution in the United States (Fig. "80).

Nineteen states
territories are producers of gypsum, although three of these
and
New
York, Michigan, and Iowa

the total quantity mined.
produce nearly 50 per cent of
The wide geologic range of gypsum deposits in the United States

can be seen from the following table
:
STATE OB
TERRITORY
Alaska
Arizona
Arkansas
STATE OR
TERRITORY
AGE
Permian or
Nevada
Triassic
Triassic
Triassic
New Mexico
New York
Permian
and Tertiary
(Pliocene)
Ohio
Tertiary
California Tertiary
Colorado
Iowa
Kansas
Oklahoma
Permian
Permian
Pleistocene
Map
New York
of
Silurian
Silurian
Pleistocene
Permian
South Dakota Permian
Texas
Permian
Permian
Michigan Lower Carboniferous
Montana Lower Carboniferous
FIG. 81.
AGE
Utah
Jurassic
Virginia
Carboniferous
Wyoming
Triassic
New York
(13,
showing outcrop of gypsum-bearing formations.

(U. S. Geol. Sun., Bull. 223.)
14)
largest producers, the
In this state, which is one of the three

occurs as rock gypsum, interbedded
gypsum
with shales and shaly limestones of Salina (Silurian) age.
The beds,
250
ECONOMIC GEOLOGY
Even bedded limestone
PLATE
FIG.
1.
drift.
XXVI
Gypsum quarry, Alabaster, Mich. Shows gypsum overlain by glacial

The dump in foreground is overburden removed from gypsum. (Photo.,
A. C. Lane.)
FIG. 2.
View
Pike Station, N. H.
Pike Mfg. Co.)
in scythestone quarry,
(Photo, loaned
(251)
ECONOMIC GEOLOGY
252
and is covered by glacial drift, but in places is overlain conformably

by red shales. It varies from 3 to 30 feet in thickness, with an
average of 16 feet, and much of it is sufficiently white for stucco.
Kansas.
Gypsum (11) is found occurring as rock gypsum, or
as gypsite, the deposits forming a belt extending across the central
part of the state in a northeast-southwest direction, and includes
three important areas, viz. Northern, or Blue Rapids, in Marshall
County, Central, or Gypsum City, in Dickinson and Saline counties,
and Southern, or Medicine Lodge, in Barber and Comanche coun-
The beds
ties.
of rock
gypsum
are of
Permian
age, interbedded
with red shales, those at the southern end of the belt being
graphically 1000 feet higher than those at the northern end.
strati-
The gypsite or gypsum dirt, which is of more recent age, is found in the
central area, as well as at a number of other localities. The spring waters
which have supplied it have leached the calcium sulphate either from
the gypsum beds or the red shales. The gypsite is found especially in the
central area, and the deposits were the first of then- kind worked in
the United States.
The product is used for fertilizer and cement plaster, and much is also
used for making Keene's cement. 1 The rock, which is quarried especially
in the northern and southern areas, is white in color, and may range from
8 to 16 feet in thickness.
Gypsum
Virginia.
is
also
found in beds of Lower Carbonif-
the Holston Valley of southwestern Virginia (22),

erous age
the deposits occurring in shales, between Carboniferous (Greenbrier limestone) and Siluro-Devonian sandstones (Fig. 73).
The
in
is faulted up against the Cambro-Silurian limestones, on

the southeast, and both the gypsum and salt deposits seem to be
limited to a narrow belt bordering on this fault.
section
The gypsum occurs
in bowlder masses in gray
and red
clays,
and
is
interesting because of the abundant but irregular occurrence of anhydrite,

which grades into the gypsum. The rock is mined partly by underground
workings, and some of the beds are fully 30 feet thick. The product is used
for land and wall plaster.
In Ohio gypsum has been obtained from the lower Helderberg beds of
Ottawa County, 10 miles west of Sandusky. The material occurs at different horizons, the beds being bent into rolls, the main ones having a thickness
of about 12 feet (15, 20).
Other Occurrences.
(24, 25),
Utah
Colorado (9, 20),

Arizona (7, 20). In the
1
jt
known in Wyoming
Montana (20), Idaho (20),
Oklahoma (16), Texas (20), -and
Additional occurrences are
Nevada (20),
South Dakota
(21),
last,
California
(17-19),
as well as in
cement made by burning gypsum
with alum or other chemicals.
(8),
New
Mexico, there are found
at high temperatures,
and then treating
GYPSUM
253
important deposits of gypsum sand, composed of gypsum grains broken

down by stream action and water from rock gypsum outcrops, and then
gathered into hills or dunes by wind action. Some of these dunes are more
than 100 feet high. The utilization of these sands in Otero County, New
Mexico, was begun in 1908.
Gypsum (6) of Permian or Triassic age is known to occur on Chichagof

Island in southeastern Alaska. The beds, which are folded and steeply
tilted,
to
have been extensively developed during the last few years and shipped
for preparation.
It comes into competition -with "similar mafrom the western states.
Tacoma
terial
The following analyses indicate the

Analyses of Gypsum.
from
different localities in the United
of
gypsum
composition
all be guaranteed as being of
cannot
Canada.
States and
They
serve
and
mainly to show variation in comaverage character,
position
254
ECONOMIC GEOLOGY
number of occurrences, those of Nova Scotia and New Brunswick being the most important, followed by Ontario, Manitoba
and British Columbia.
In
Nova
Scotia there are
many
deposits,
distributed over the northern half of the province from
Windsor
GYPSUM
255
to Cape Breton, while in New Brunswick the deposits are located

chiefly in the southern part of the province, with Hillsborough
and Plaster Rock as the two important localities.

The gypsum of these two provinces is of Lower Carboniferous
age, and appears to form more or less lens-shaped deposits,
associated with shales and limestones. Anhydrite is a common
accompanying rock (PI. XXV, Fig. 1), and while in many cases
it is said to underlie the gypsum, it often occurs in it, in the form
of irregular masses and veinlets.
Considerable high-grade white
is
near
quarried
Hillsborough, N. B. Gypsum also of
gypsum
Lower Carboniferous age is known on the Magdalen Islands in
the Gulf of St. Lawrence.
At York
gypsum,
in southern Ontario, the
interstratified
The material
is
white,
with
and
Onondaga formation
carries
limestone, dolomite and shale.

forms lenticular masses averaging
4 feet in thickness, with some as much as 11 feet thick. The

northern Ontario deposits are not worked.
Gypsum is actively worked in northern Manitoba northwest
of Lake St. Martin.
The thinly-bedded deposits, which are sometimes overlain by gypsum earth, may be 10 feet thick, and appear
to be of Upper Silurian or Lower Devonian age.
British Columbia contains several localities.
That near
Spatsum on the Thompson River is interbedded with crystalline
limestone, argillites and volcanic rocks, while a second, east of
Grand Prairie, shows one bed over 100 feet thick, and a second 30
feet thick, associated with gray schists and crystalline limestone.
Other Foreign Deposits. 1
Of these France is the most
important, the extensive Oligocene deposits of the Paris basin
being a most important source of supply. The gypsum contains
10-20 per cent of calcium carbonate, and soluble silica, which is
said to increase the hardness of the set plaster.
only other important European producer, the
England
chief
is
the
deposits
being found in the Triassic of Cumberland, Nottinghamshire and

Staffordshire.
number
of other countries contribute to the World's supply
(See table p. 258) but they are far behind the countries mentioned.
Uses (i, 12).
Gypsum is sold either in the ground, uncal,
cined condition, or after calcining and screening.
Uncalcined gypsum is used in large quantities as a retarder

for Portland cement, and in the past much was employed for
1
For resumS see Dammer and Tietze, Nutzbaren Mineralien, II: 64, 1914.
ECONOMIC GEOLOGY
256
purposes under the name of land plaster. Other applications are for crayon manufacture, as an ingredient of steam pipe
coverings, as a body for some paints, and as a food adulterant
fertilizing
under the name of
terra alba.
known
The pure white rock gypsum,
as alabaster, has been used for statuary, basins, vases

other objects for interior decoration.
Calcining
of its water
bining with
and
When
heated to 250 F., gypsum loses a portion

but if finely ground has the property of recomheated to 300 F. to 400 F., it is said to lose this power
Gypsum.
of hydration,
it.
If
called dead-burned. 1
is
up the
and
crystals into
minute
In addition to dehydration, burning also breaks

The set is due to the formation of
particles.
a crystalline network of the rehydrated grains.

Since calcined gypsum sets in from 6 to 10 minutes, some retarding material, such as organic matter from slaughter-house refuse, is often added
to it, and thus the setting process may be delayed from 2 to 6 hours.
Those plasters which set slowly are termed cement plasters.
The following analyses show the composition of (1) uncalcined gypsum;
(2) the calcined rock; and (3) the plaster after it has taken up water and
set.
From these it will be seen that the plaster takes up the amount of
water
lost in calcination.
SERIES OF ANALYSES SHOWING CHANGES IN GYPSUM DURING BURNING

AND AFTER SETTING
GYPSUM
S j
!
257
258
ECONOMIC GEOLOGY
IN THE UNITED STATES, 1910-1914,
SHORT TONS
MARKETED PRODUCTION OF GYPSUM

IN
GYPSUM
259
REFERENCES ON GYPSUM
PROPERTIES, ORIGIN, AND TECHNOLOGY.
1. Eckel, Cements, Limes, and

N. Y., 1907. la. Grabau, Principles of Stratigraphy,
2. Grimsley and Bailey, Kas. Geol. Surv., V, 1899.
2o. Rogers,
p. 373.
Sch. of M. Quart., XXXVI: 123, 1915.
(Anhydrite in U. S.) 3.
Wilder, Eng. and Min. Jour., LXXIV: 276, 1902. 4. Clarke, U. S.
Plasters, 2d. ed.,
Geol. Surv., Bull. 616: 1916.
AREAL.
(Origin.)
others, U. S. Geol. Surv., Bull. 223, 1904.
(United
Alaska: 6. Wright, C. W., U. S. Geol. Surv., Bull. 345:
Adams and
5.
States.)
124, 1908.
394, 1896.
(S.
E. Alas.)
California:
8.
Arizona: 7. Blake, Amer. Geol., XVIII:

Hess. U. S. Geol. Surv., Bull. 413, 1910.
XXI:
Iowa:
(Larimer Co.)
35, 1900.
XII: 99, 1902,' and Jour. Geol., XI: 723,
Kansas: 11. Grimsley and Bailey, Kas. Univ. Geol. Surv.,
1903.
Michigan: 12. Grimsley, Mich. Geol. Surv., IX, Pt. 2, 1904.
V, 1899.
Nevada: 126. Rogers, Econ. Geol. VII: 185, 1912, and Jones,
Ibid., VII: 400, 1912.
(Origin gypsum and anhydrite, Ludwig Mine.)
New Mexico: 12c. Herrick, Jour. Geol.,. VIII: 112, 1900. (White
New York: 13. Merrill, N. Y. State Museum, Bull. 11:
sands.)
14. Newland and Leighton, N. Y. State Mus., Bull. 143,
70, 1893.
OklaOhio: 15. Orton, Ohio Geol. Surv., VI: 696, 1888.
1910.
homa: 16. Gould and Herald, Okla. Geol. Surv., Bull 5: 98, 1911.
South Dakota: 17. U. S. Geol.
Also L. C. Snider, Ibid., Bull. 11.
18. Todd, S. D. Geol. Surv., Bull.
Surv., Geol. Atlas Folios, 85: 6.
United
3: 99, 1902. 19. O'Harra, S. Dak. Sch. of M., Bull. 8, 1908.
Colorado:
9.
Lee,
Stone,
10. Wilder, la. Geol. Surv.,
20. Adams and others, U. S. Geol. Surv., Bull. 223, 1904.

VirUtah: 21. Boutwell, U. S. Geol. Surv., Bull. 225: 483, 1904.
23. Watson,
ginia: 22. Eckel, U. S. Geol. Surv., Bull. 213: 406, 1903.
Min. Res. Va.: 327, 1907. (Lynchburg.)
Wyoming: 24. Knight,
States:
Wyo. Exper. Station, Bull. 14: 189, 1893. 25. Slosson and Moody,
Wyo. Coll. Agric. and Mech., 10th Ann. Rept.,1902.
Canada:
eral.)
B.)
Can. Dept. Mines, Mines Branch, No. 245, 1913. (Gen(N. S. and N.
Ibid., Summary Rept. for 1910.
(Man, and origin.)
28. Wallace, Geol. Mag., VI, 1: 271, 1914.
26. Cole,
27.
Kramm,
CHAPTER
VIII
FERTILIZERS
UNDER
term are included a number of mineral substances,

marl (p. 191), gypsum (p. 244), phosphate of
lime, greensand, guano^ kainite (K2SO4, MgS04, MgCl2, 6 PbO)
(p. 213), and niter (p. 232), which are of value for adding to the soil
to increase its supply of plant food and also in some cases correct
Some of these have other uses as well, and
its physical condition.
have been discussed elsewhere on those pages indicated by the
limestone
this
(p. 187),
numbers following them in the foregoing lines.

This occurs both as crystalline phosphate
Phosphate of Lime.
of lime, or apatite, associated with crystalline rocks and rock phosphate usually associated with stratified rocks.
This mineral when pure contains about 90 per
Apatite (6, 8)
cent tricalcic phosphate, and 10 per cent calcium fluoride, which
.
be replaced by calcium chloride. It is widely distributed in

some igneous and metamorphic rocks, especially granites, gneisses,
and some crystalline limestones, but rarely in sufficient quantity or
may
in sufficiently concentrated masses to render its extraction profitable, at least while the supply of amorphous phosphate lasts.
mining to a few
where it is associated with other valuable minerals.
In the United States apatite has been produced for several years
at Mineville, N. Y. (7) where it occurs disseminated in small grains
through the magnetite, forming sometimes as much as 5 per cent of
So, competition with rock phosphate has restricted
localities
In the process of magnetic separation the apatite is reas tailings, the first grade of these carrying about 60 per
cent tricalcium phosphate, and the second about 30 per cent.
They are used in fertilizer manufacture.
the ore.
moved
A unique as well as extensive occurrence of phosphatic material is

found at two localities in Nelson (figured under Titanium) and Roanoke
The rock which Watson has named Nelsonite (8 a)
counties, Virginia.
consists of a hard granular aggregate of white apatite and black ilmenite,
and forms dike-like masses in metamorphic igneous rocks. The commercial
value of this material as a source of phosphate remains to be proven.
260
FERTILIZERS
261
Large quantities of crystalline apatite were formerly produced

and Quebec, where the material is found in pegmatites
associated with much pyroxene, phlogopite, hornblende, etc.
in Ontario
The output
at present
is
very limited, as the material cannot
compete with the cheaper and more easily ground rock phosphate.
That produced is a by-product from mica mining.
Rock Phosphates (4, 4a, 8).
These, though composed chiefly
of phosphate of lime, also carry variable quantities of other substances as will be explained below.
They are sometimes called
phosphorites, although this term should probably be restricted
to the purer, denser, fine-grained forms. 1
Rock phosphates may be roughly classified as follows:

I. Bedded deposits, consisting of, (a) beds of massive
phosphate,
lens-shaped character, and varying purity;
sedimentary rocks; (c) bone beds mixed with more
or less phosphatic material.
II. Replacement deposits, formed by the leaching of phosphate from guano or higher-lying phosphatic formations, and
of continuous
or
(6) nodules in
its
deposition in lower-lying calcareous rocks.
fillings deposited from solution, and including;

in limestones, or (6) fissures in limestones or
cavities
(a) irregular
other rocks. These represent phosphates of high purity, and
III.
Cavity
some replacement may accompany the
filling.
IV. Residual deposits.

V. Mechanically formed deposits (placers) of marine or stream
,
origin
Minerals in Phosphate Rock.

The chief minerals in phosphate rock are calcium phosphates. According to Rogers (13)
phosphate rock appears to be a mixture of two minerals,
amorphous collophanite, largely a solid solution of calcium carbonate in calcium phosphate, and crystalline dahllite, a calcium
carbonophosphate with the formula CaeÔ^CaCOsiHaO,

analogous to fluorapatite. The amorphous collophanite graduHydroapatite is sometimes present in
ally changes to dahllite.
mammillary masses resembling chalcedony.
Phosphates of iron or aluminum may be present in small
amounts, and calcium carbonate is not rare, though never present

Other substances may include quartz, clay
and even small amounts of fluorine, titanium, manganese, etc.
in large quantity.
1
See Dana, Syst. Min., p. 762; Dammer and Tietze, Nutzbaren Mineralien, II:
106, 1914; Merrill, Non-Metallic Minerals, p. 268; Stutze, Nicht-Erze, p. 266.
ECONOMIC GEOLOGY
262
These may be objectionable beObjectionable Impurities.

cause they take the place of just so much phosphate, or because
they interfere with the process of manufacturing acid phosphate.
Iron and alumina are the most objectionable from the latter view-
and hence phosphate
is sold under a guarantee not to

2
to
4
cent
of
Alumina if present as silicate is
exceed
iron.
per
said to be more injurious than aluminum phosphate.
point,
amount
small
of calcium carbonate is beneficial, since its
reaction with the acid added generates heat which promotes

subsequent reactions among the other constituents, and the car-
bon dioxide gas given off facilitates drying. Fluorine if present

any quantity is objectionable because of the obnoxious gas
in
when the phosphate is treated with sulphuric acid.

is met with more in using apatite than with rock
generated,
This trouble
phosphate.
of
Origin
Phosphate Deposits
somewhat varied mode

is
(2,
4,
8).
Considering the
of occurrence of
obvious that different deposits
may
amorphous phosphate it
have been formed in different
ways.
We
may perhaps regard the igneous and other crystalline rocks

as the ultimate source of the element phosphorus.
The phosphate
minerals, of which apatite is the commonest, may on the weathering of the rock be attacked by the soil waters, different inorganic
phosphates showing different degrees of solubility, and their

solubility varying also with the conditions.
Thus the presence of decaying organic matter in water seems
to increase the solubility of phosphate minerals, and carbonated
water appears to exert a similar influence, as does also sodium
chloride. 1
Surface waters gather carbon dioxide from the air,
or from the soil, where they also collect organic acids.
These
then attack the phosphate compounds found in the rocks.
While a part of this dissolved phosphate of lime is no doubt
taken up by plants or held in the soil, other portions may be

carried to the sea.
There a portion of it may be abstracted by
marine animals in the construction of their

skeletons.
shell covering or
actual percentage of calcium phosphate in these
not high, but it is not to be overlooked.
The
hard parts is
It has been found
in the case of certain
swamp waters
in
South
Carolina, that calcium phosphate was dissolved when organic

matter was present to furnish organic acids. If these same
1
Patten and Waggaman, Dept. Agric., Bur.
Soils, Bull. 52.
FERTILIZERS
263
solutions stood for a time over marl, the phosphate was prePhosphate may also be precipitated on the sea
cipitated.
floor, either as grains or nodules, or sometimes apparently by
replacement of calcium carbonate of shells by calcium phosphate.
marine deposit might therefore contain phosphate formed
by chemical precipitation, as well as that contained in bones and

shells, and such a deposit might or might not be sufficiently rich
to work.
These primary deposits, however, may become the source of

richer ones of a secondary nature by: (1) Leaching out of calcium
carbonate from phosphatic limestones, leaving the phosphate
behind; (2) removal of the phosphate by solution, and its
redeposition by replacement at a lower horizon; or (3) erosion
phosphate formation, and mechanical concentration of

nodules and bones, in streams.
We can, therefore, see that phosphate deposits may in some
of the
cases exhibit considerable complexity of origin, involving in

cases several shifts of the phosphatic material.
some
This state is at present the most important

Florida (13, 14, 15).
phosphate producer, although the full extent and value of the
deposits were unsuspected until the discovery of large beds along
the Peace River in 1887. Three distinct types have been recognized, viz., hard rock, land pebble, and river pebble, but the last
Their mode of occuris no longer important, or even worked.
rence, origin
and location
is different.
The hard rock phosphate
lies in
a general north-south belt,
about 100 miles long, roughly paralleling the Gulf Coast, while
the land-pebble deposits are found farther south, chiefly in Polk
and Hillsboro counties (Fig.

The hard rock phosphate,
84).
rests on and replaces the porous and

cavernous Ocala limestone (Lower Oligocene). It consists of
boulders and lumps of phosphate rock, mixed with sands, clays,
flint nodules, etc., the phosphate often forming more than 10 to
25 per cent of the entire mass.
There have been different opinions expressed regarding the
origin of the hard-rock formation, but Sellards (14) especially,
has shown that the Ocala limestone was formerly covered by the
ECONOMIC GEOLOGY
264
Chattahoochee limestone and Alum Bluff sands.

disintegrated in situ,
81-
FIG. 84.
Map
These have
and the Alum Bluff formation, which is
Longitude
S3
West
from
82
Greenwich
showing phosphate areas of Florida.

Surv., 7th Ann. Kept.)
distinctly phosphatic, has
(After Sellards, Fla. Geol.
by leaching supplied the phosphate

which was carried downward and redeposited at a lower level,
often by replacement of the limestone, the shells of which were
in some cases completely phosphatized.
There was also some
PLATE XXVII
FIG.
FIG. 2.
1.
Rock phosphate mine near
Ocala, Fla.
(Photo.,
A. W. Sheafer.)
Shows the alternating layers of

Phosphate beds, Montpelier, Ido.
(W. F. Ferrier, photo.)
limestone and phosphate.
(265)
ECONOMIC GEOLOGY
266
the phosphate in cavities, as shown
of
precipitation
botryoidal and
by the
stalactitic forms.
The thickness
from 30 to 50
of the hard-rock phosphate formation is often

feet, and in exceptional cases 100 feet (14), the
high-grade material averaging 77 to 80 per cent tricalcic phosphate.

The land pebble phosphate (Fig. 84) is a conglomerate of peb-
sands ar.d clay, formed by the sea advancing, probably with

oscillations in level, across the exposed surface of a great
phosphatic marl, the Alum Bluff formation, while the overburden
sands represent that part of the formation deposited following
bles,
minor
accumulation
of the pebble conglomerate.

Within the
the
rock
has
been
bed,
improved by secondary enrichphosphate
ment by downward- and lateral-moving waters, because the pebbles
the
of the phosphate carry considerably

parent rock.
more P20s than those
of the
The pebble phosphate appears
to be 8 to 12 feet thick, with

In the workable deposits the
phosphate makes up 10 to 25 per cent of the whole, while the
marketed material runs from 60-74 per cent tricalcic phosphate.
maximum
of
18 to
20
feet.
Hard-rock phosphate, if in large lumps, is first crushed, after which, it,

together with finer material, passes through a log washer to separate dirt
and sand. Land pebble is put through a similar washing process, sometimes preceded by screening. After leaving the cleanser, hard rock is sorted
on a picking table.
Both kinds of phosphate must be dried before shipment. Not a little
phosphoric acid is to be regarded as lost in the low-grade material which
is thrown on the dump, and methods for saving this are needed.
South Carolina.
Phosphate is found both on the land and in the river
bottoms in a belt about 60 miles long lying inland from Charleston and
The phosphate, which rarely averages much over
Beaufort (8, 20, 21).
1
foot in
tains
thickness,
is
many bones and
commonly of nodular
The presence of
teeth.
character, and often conthese animal remains, in-
cluding both land and marine forms, has given rise to the belief that the
deposits were caused by the accumulation of bones and excrements along
a shore line, probably of Upper Miocene (Tertiary) age. Leaching of these
remains
may have
permitted a later replacement of limestone or the forma-
tion of phosphatic concretions in swamp bottoms.

Two forms are recognized, viz., land rock (the type now mined) and river
rock
The foimer ranges from 1 to 3 feet in thickness and is overlain by
The
river rock is little more than water-worn fragments

mined from the river channels. The rock now shipped
averages about 61 per cent bone phosphate.
The South Carolina phosphate rock was worked as early as 1867, and
green sand marl.

of the first type,
and
is
the production increased up to 1893, but since then

steadily.
it
has fallen
off
almost
FERTILIZERS
267
Tennessee (22-28).
Since the recognition, in 1893, of considerable quantities of high-grade phosphates in western middle
Tennessee (Fig. 85), there have been important developments
of the deposits.
Three types of
phosphate deposits are recognized,
viz.
brown,
blue and white.
Brown Phosphate (26). This is more or less confined to the

southwestern portions of the Central Basin of Tennessee, with
Flo. 85.
Map
Mount
Pleasant
showing distribution of phosphates in Tennessee.

Ruhm, Eng. and Min. Jour., LXXXIII.)
as
the
most
important
(Adapted from
producing
district
(Fig. 85).
a residum filling solution cavities or pockets in

limestone
phosphatic
(Fig. 87), which have been formed by the
of
action
surface waters, that removed the lime carleaching
bonate. Where the parent rock has not been exposed to weatherIt occurs as
ing action no concentration has occurred.
Two
types of deposit are recognized,
deposits (Plate
XXVIII,
Fig. 2) in
viz.:
(1)
which a more or
Rim
less
or collar
connected
268
group encircles a hill, and (2) Blanket deposits formed where the
limestone is exposed to weathering action over a considerable area.
The two types grade into one another.
UNCONFORMITY
CHATTANOOGA SHALE
UNCONFORMITY
CLIFTON LIMESTONE
0-60
-UNCONFORMITY-
FERNVALE FORMATION
SHALES AND LIMESTONE
0-40
U NCONFORMITY
LEIPERS FORMATION
C- 100
JNCONFORMITY-
CATHEYS FORMATION
0- 100
BIGBY LIMESTONE
30- 100
HERMITAGE FORMATION
40- 70
-UNCONFORMITY-
CARTERS LIMESTONE
40-60
LEBANON LIMESTONE
70- ICO
HEAVY BLACK REPRESENTS PHOSPHATE
FIG. 86.
Vertical section showing geologic position of Tennessee phosphates.

(After Hayes.)
A dominant factor is the presence of major joints striking

N. 60 W., and it is along these that the weathering proceeds
(Fig. 87), resulting in long
XXVIII,
narrow trenches, called
cutters (Plate
Fig. 1), filled with the commercially valuable phosphate.
PLATE XXVIII
FIG.
1.
View showing phosphate
cutters,
Mt. Pleasant, Tenn.
(J. S.
Hook,
photo.)
FIG.
2.
Collar deposit of
brown Tennessee phosphate around base
of
hill.
Hook, photo.)
(269)
(J. S.
ECONOMIC GEOLOGY
270
5
S=Soil
FIG. 87.
LS.
C= Clay Seam
= Limestone
Sections, showing
(After Hook,
J=Jointing
= Phosphate
development of "cutters" of brown phosphate,

Min. Res, Tenn., IV, No. 2, 1914.)
FERTILIZERS
These average about 15
feet in depth,
271.
and 10
feet in width,
maxima of 45 feet and 20 feet respectively.

The commercial rock is either of a porous,
structure, or of a loose,
is
platy,
with
coherent
sandy nature.
The Bigby limestone (Ordovician) from which the phosphate

derived, is when fresh, of dense, crystalline nature, usually
banded with thin black layers, which are more phosphatic than
the rest of the rock, and produce the best quality of platy phosphate.
After mining, the brown phosphate is put through a washer to
eliminate clay, iron oxide, chert, limestone lumps, and other
The washed product is sold under a guarantee
foreign matter.
of from 70 to 80 per cent bone phosphate, the maximum specified
amounts of combined iron and alumina in each case being 6^
and 4 per cent.
Blue Rock (26).
In Hickman, Lewis, Maury, and Perry
especially, there occurs a phosphatic stratum, just
below the Chattanooga shale in the Devonian, which varies
from a few inches up to 2 or 3 feet in thickness. The more
purely phosphatic portion, known as blue rock, grades into nonphosphatic sandstone or shale. Structurally it may be oolitic,
compact, conglomeratic or shaly. Just above it in the Chatta-
counties,
nooga shale
is
a layer of
flat
phosphate nodules.
The blue rock appears
to be a sediment, which has not been

altered since its deposition, the phosphatic material having been
supposedly derived from the subaerial decay of phosphatic

Ordovician limestones, and mechanically concentrated by ocean
currents into the lenticular deposits from which it is now mined.
The
blue rock after mining is crushed fine.

This is found in Perry and
White Phosphate.
(23, 25, 27, 28).
Decatur counties, and is directly associated with Silurian limestone and with breccias of Camden chert. Three varieties of
phosphate are recognized, all of which are clearly the result of
transportation and deposition
(1) Stony,
representing an
by underground water.
originally
siliceous
They
are:
limestone, from
which the calcium carbonate has been dissolved, and calcium

phosphate deposited in its place. The phosphate, which forms
27 to 33 per cent of the rock is therefore a replacement; (2)
Breccia, forming irregular masses of surface character, and consisting of small angular fragments of chert, embedded in a matrix
of phosphate;
(3)
Lamellar, consisting of thin parallel layers or
272
ECONOMIC GEOLOGY
from solutions, and filling pre-existing solution

This is the
channels, or as a matrix around chert fragments.
plates, deposited
most important type.
The Phosphatic material has probably been derived from the

formerly overlying Devonian rock, but since its deposition is
closely associated with the movement of water through irregular
solution channels, its distribution must be regarded as more or
less uncertain.
ANALYSES OF PHOSPHATE
FERTILIZERS
Pre-Upper
Carboniferous
Upper Carboniferous
(Phosphate beds near base)
273
Post-Upper
Carboniferous
Map of parts of Idaho, Wyoming, and Utah, showing localities of Upper

Carboniferous rocks containing phosphate beds. (After Weeks and Ferrier, U. S.
FIG. 88.
-
Geol.
Sun., Bull. 315, 1906.)
274
Thick
overlyir
lime
ECONOMIC GEOLOGY
FERTILIZERS
275
for a distance of 200 miles north of Ogden, Utah,

and Wyoming, and have also been found near Ellis-
They extend
into Idaho
FIG. 90.
Section showing structure of phosphate bearing formations in
Wyoming.
(U. S. Geol. Sun.)
SoeJe in feet
200
100
FIG. 91.
Section of Carboniferous strata on north side of Montpelier Creek, Ida

Weeks and Ferrier, U. S. Geol. Sun., Bull. 315, 1906.)
(After
and other places in Montana. The earlier reports

place them in the Park City formation of the Permian, but some
of the later ones assign the phosphate beds to the Phosphoria
ton, Melrose,
276
ECONOMIC GEOLOGY
formation, which is regarded as the equivalent of the two upper

of the Park City, and also of the phosphatic beds above
members
the Quadrant formation of the Melroae and Elliston district.

The phosphate forms beds interstratified with limestones and
having been much disturbed by

Those of the Georgetown area have been
shales, the series in all cases
folding and
faulting.
involved in the great Bannock thrust fault. 1

In hand specimens the phosphate is seen to be dense, with an
It is dark brown when fresh, but becomes bluish
oolitic texture.
white on weathering.
Under the microscope it shows an isoand a doubly refracting
tropic mineral, possibly collophanite,
phosphate, possibly quercyite.

The lime phosphate content of the workable beds varies from
65 to 80 per cent with an average of 70 per cent.
Just how the phosphate has been formed is not conclusively
settled, the only certain fact being that it has been precipitated in
some manner on the ocean

The following analyses
floor.
will
serve to
show
ANALYSES OF WESTERN PHOSPHATES
its
composition:
FERTILIZERS
277
Although the western phosphate beds seem to lie chiefly in the

Permian, still others are known to occur in the Mississippian of
Utah. 1
Arkansas (10, 11, 12).
Phosphate deposits have been developed on
Lafferty Creek, on the western edge of Independence County, but the beds
FIG. 92a.
Oolitic phosphate,
Cokfcville,
Wyo.
X30.
FIG. 926.
ant,
Bigbee limestone, Mt. PleasTenn. Oolitic bodies largely
phosphate; light ground calcite

with phosphate grains.
X30.
-extend from about 10 miles northeast of Batesville, to St. Joe in Searcy

County, a distance of about 80 miles. The phosphate which forms a
bed 2 to 6 feet thick in the Cason shale of the Ordovician is light gray,
homogeneous and conglomeratic with small pebbles. It carries from 25
to 73 per cent lime phosphate.
The following section is shown on Lafferty
Creek (Fig. 93).
ECONOMIC GEOLOGY
278
Clay and Chert
3 Inches
''./
~~~,
__;
Clay shale
U7T
14
"
Phosphatic shale
'/:-.$
"
41.27$
55.27^
Ca 3
..
/>
Phosphatlc and*tont
FIG. 93.
Section in Lafferty Creek, Ark., Phosphate district.

and Newsom, Ark. Agric. Exp. Sia., Bull. 74.)
'After
Branner
The true natuie of these phosphate deposits does not appear to have
been recognized for some years.
Branner and Newsom considered them to be deep-sea (though not abysmal)
deposits, formed from the droppings of fishes and other marine animals, and
to accumulations of organic matter that settled to the bottom of the quiet
waters.
Purdue believed the beds to have been laid down near shore as the sea
advanced landward, and the phosphatic nature as due mainly to fragments
of organic matter, but may have been in part the droppings of marine
The conglomerate character is thought by him to confirm the

shallow-water theory.
Other Phosphate Occurrences.
Phosphate, in the form of nodules,
white vesicular -rock, and in limestone fragments, occurs along the contact
of Oriskany (Devonian) sandstone and Lower Helderberg (Silurian)
limestone in Juniata County, Pennsylvania (19). It contains 30 to 54
per cent bone phosphate. Nodular phosphate, although not worked for
fertilizer, is known to occur in Cretaceous and Tertiary strata in Alabama
(9), Georgia (16), North Carolina (18), and Virginia (29, 30).
Phosphate
is now being obtained also from the Trenton of central Kentucky (17).
animals.
Canada. (39o). The finding of phosphates at a definite geologic

horizon in the western United States has encouraged the Canadian geologists to
make
a search for this material in the con-
tinuation of the phosphate-bearing formations to the north of

the international boundary, resulting in the finding of phosphate
rock in the Upper Carboniferous a short distance north of Banff,

"
"
in the Rocky Mountains. The finds consist of
float
phosphate
and also a phosphatic quartzite at the contact between the
Upper Banff limestone and the Rocky Mountain quartzite.
FERTILIZERS
The
latter,
279
which contains 7.6 per
to work, but
its
cent. P2Os, is not rich enough

warrants
further search.
discovery
Under this name are included surface deposits of

Guano (45, 46).
excrement, chiefly of birds. Penrose (8) recognizes two classes: (1) soluble
guano, of recent origin, usually found in sheltered places, and containing
not only phosphoric acid in readily available form, but also considerable
(2) Leached guano, which has lost its soluble constituents by
nitrogen.
the action of rain or sea water, and which contains practically no nitrogen,
while the phosphoric acid content, though usually high, is relatively in-
guano of commerce was formerly obtained

the Incas, as well as the early Spaniards, valued
it so highly that a death penalty was imposed for killing the birds which
produced it. These deposits, from which many thousand tons have been
soluble.
Most
of the soluble
from Peru, where,
it is said,
obtained, are now exhausted. No large deposits of bird guano are known
Leached guanos occur on islands in the southern
in the United States.
and in the West Indies.

Bat guano has been found in the caves of Kentucky, Texas (46), and
many other states, but few of the deposits have proved large enough to
work, and none are of great extent, although one cave in Texas was known
to yield 1000 tons.
The following analysis is representative: ammonia,
Pacific
9.44 per cent; available phosphoric acid, 3.17 per cent; potash, 1.32 per
cent.
Greensand.
This term
is
applied to beds of marine origin,
made up
in
large part of the green sandy grains of glauconite, the hydrated silicate
of iron and potash.
It also contains small amounts of phosphoric acid.
Greensand (29) is found at many localities in the Cretaceous and Tertiary
formations of the Atlantic Coastal Plain, but New Jersey (43) and Virginia
are the two important producers. The New Jersey greensand is spread
on the soil in its raw condition, but that from Virginia is dried and ground
for use in commercial fertilizers.
The following analyses show its variable composition, and the comparatively small amount of P-2O5 and K2O necessary to make it of value as
a
fertilizer.
ANALYSES OF GREENSAND
ECONOMIC GEOLOGY
280
The raw materials which can be used for this purUnited States.
pose are guano, bone, apatite, and phosphate rock. Of these the last is
the most important. Only guano that is easily obtained and high in nitrogen
can compete with phosphate rock, while the chief objection to apatite is,
the cost of mining, and the evolution of fluorine gas when treated with
in the
sulphuric acid.
Foreign Deposits
Next
(4).
to the United States,
North Africa ranks
as an important producer, the deposits of Algiers and Tunis being of conThese lie chiefly on the boundary between the Cretaceous
siderable extent.
and Tertiary, and consist of phosphatic beds, with phosphate nodules, teeth,
and bones, and gypsum, interstratified with phosphatic marls and limestones.
Some
of the deposits are 3 meters thick.

number of producing localities, most of which yield
phosphate from bedded deposits of Cretaceous age, or in the Pyrenees, beds
In France there are a
of upper Devonian age. An exception is formed by the Quercy phosphates,

which occur as veins in limestone.
The Belgian deposits are also bedded and found in the Cretaceous.
Production of Fertilizers.
The production of phosphate in
the United States for several years was as shown in the table on
page 281.
The following table shows what a large

of
the
percentage
phosphate rock produced in the United States
Exports and Imports.
is
exported:
PRODUCTION AND EXPORTATION OF PHOSPHATE ROCK IN THE UNITED STATES,

1909-1914, IN
YEAR
LONG TONS
FERTILIZERS
I
i
s
c
E
PH
SB
p
i
c
c
s
PH
281
282
it
ECONOMIC GEOLOGY
World's production. The table given below is of interest, since

brings out clearly the leading position of the United States as a
producer of phosphates.
WORLD'S PRODUCTION OF PHOSPHATE ROCK, 1910-1912, BY COUNTRIES,
IN METRIC TONS
FERTILIZERS
283
State
Museum, Bull. 102: 50, 1906. (New York.) 8. Penrose, U. S.

Geol. Surv., Bull. 46, 1888.
80. Watson, Min. Res. Va.:
(General.)
86. de Schmid, Dept. Mines, Mines Branch, No.
(Va.)
300, 1907.
118,
1912.
Phosphates: Alabama: 9. Smith, Ala. Geol. Surv.,

Arkansas: 10. Branner, Amer. Inst. Min. Engrs.,
11. Branner and Newsom, Ark. Exper. Sta.,
580, 1897.
(Canada.)
Bull. 2:
1892.
9,
XXVI:
Trans.
Bull. 74, 1902.
12. Purdue, U. S. Geol. Surv.. Bull.

analyses.)
Florida:
13. Eldridge, Amer. Inst. Min. Engrs.,
13a. Matson, U. S. Geol. Surv., Bull. 604,
Trans., XXI: 196, 1893.
1915.
14. Sellards, Fla. Geol. Survey, 3d Rep.: 17, 1910; 5th Rep.:
315:
(Many
1907.
463,
15. Waggaman, U.
23, 1913; 7th Rep.: 25, 1915.
Soils, Bull. 76, 1911.
Georgia: 16. McCallie,
S. Dept. Agric.,
Ga. Geol. Surv.,
Bull. 5-A, 1896.
Kentucky: 17. Foerste, Ky. Geol. Surv., 4th Ser.,
I: 387, 1913.
North Carolina: 18. Carpenter, N. Ca. Agric. Exper.
Bur.
1894.
(Marls and phosphates.)
110,
Pennsylvania:
U. S. Geol. Surv., 17th Ann. Rept., Ill: (ctd.): 955,
1896.
South Carolina: 20. Rogers, U. S. Geol. Surv., Bull. 580:
21. Waggaman, U. S. Dept. Agric., Bur. Soils, Bull. 18,
183, 1914.
1913.
Tennessee: 22. Barr, Amer. Inst. Min. Engrs., Bull. Sept.,
1914.
(Mining and washing.) 23. Eckel, U. S. Geol. Surv., Bull.
213: 424, 1903.
(Decatur County.) 24. Hayes, U. S. Geol. Surv.,
21st Ann. Rept., Ill: 473, 1901. 25. Hayes, Ibid., 16th Ann. Rept.,
IV: 610, 1895.
(White phosphate.) 26. Hook, Res. of Tenn., IV,
Bull.
Sta.,
19. Ihlseng,
No.
1,
2,
1914.
1915.
(Brown and blue phosphate.)
(White phosphate.)
28.
27.
Hook,
Waggaman, U.
S.
Ibid.,
V, No.
Dept.
Agric.,
(General.)
Virginia: 29. Stose, U. S.
Geol. Surv., Bull. 540: 383, 1914. 30. Watson, Min. Res. Va.: 302,
1907.
Western States: 31. Weeks and Ferrier, U. S. Geol. Surv.,
Bur.
Soils,
Bull.
81,
1912.
32. Blackwelder, Ibid., Bull., 470: 452, 1911.

449, 1907.
33. Schultz and Richards, Ibid., Bull. 530:
267, 1913.
35. Blackwelder,
34. Gale and Richards, Ibid., Bull. 430, 1910.
Bull. 315:
(E.
Ido.)
(Ido.)
430: 82, 1910.

(Utah.) 36. Pardee, Ibid., Bull. 530:
(Mont.) 37. Richards and Gale, Ibid., Bull. 577, 1914.
38. Stone and Bonine, Ibid., Bull. 580: 373, 1914.
(Mont.)
(Ido.)
39. Waggaman, U. S. Dept. Agric., Bur. Soils, Bull. 69, 1910.
(General.)
Canada: 39a. Adams and Dick. Report for Can. Conserv'n Com.,
Ottawa, 1915. (Phosphate in Rocky Mts.) Greensand: 40. Clark
Ibid.,
285,
Bull.
1913.
and Martin, Md. Geol.
(Maryland.)
Surv., Rept. on Eocene, 1901.
Cook, Geol. of N. J., 1868: 261, 1868. 42. Parsons, U. S. Surv.
Min. Res., 1901: 823, 1902. (General.) 43. Prather, Jour. Geol.,
XIII: 509, 1905. (N. J. glauconite.) 44. Watson, Min. Res. Va.:
Guano: 45. Penrose, U. S. Geol. Surv., Bull. 46: 117, 1898.
396, 1907.
46. Phillips, Mines and Minerals, XXI; 440, 1901,
(Texas Bat Guano.)
41.
CHAPTER IX
ABRASIVES
Under this heading are included those natural
Introductory.
products which are employed for abrasive purposes. Since the
main use of some is not for work of abrasion, they are simply referred to briefly in this chapter, the detailed description of them
being given on another page. Brief reference will also be made
to some artificial compounds which come into serious competition
with the natural ones.

While some abrasive substances occur as constituents of
veins, or in disseminated form, the great majority form a part
of rocks of either sedimentary, igneous, or metamorphic origin,
and of various degrees of consolidation. They are widely dis-
ributed both geologically and geographically, but since the localities of production change from time to time, their distribution
can be better illustrated by the table on page 286 than by

a map.
Millstones and Buhrstones l (2) are stones of large diameter
used for grinding cereals, paint ores, cement rock, barite, fertilizers,
The American stones are either coarse sandstone or quartz
etc.
conglomerate, and are quarried at several points along the eastern
side of the Appalachian Mountains from New York to North Carolina,
the most important being the
quarried in the
Shawangunk Grit (Silurian)

Shawangunk Mountains of eastern New York
are also quarried in Pennsylvania, North Carolina,

and Virginia (22). The material adapted to millstones is very
Some of the stone is also cut into chasers, used
limited in extent.
Some
(20, 21).
for grinding quartz
and
grinding machinery the

in recent years.
Many
many.
1
Owing
feldspar.
demand
to the use of improved
for millstones
has fallen
off greatly
buhrstones are imported from France, Belgium, and Ger-
Those from the
first
two
localities are hard, cellular rocks,
The term buhrstone belongs properly to those millstones made

full of cavities, some of them representing casts of shells.
donic rock,
284
of a chalce-
PLATE
FIG.
FIG.
2.
1.
XXIX
Grindstone quarry, Tippecanoe, Ohio.
(J.
H.
Pratt, photo.)
peridotite and gneiss, Corundum Hill, Ga.

(After Pratt, U. S. Geol. Sura., Bull. 180.)
Corundum vein between
(285)
286
ECONOMIC GEOLOGY
TABLE SHOWING ABRASIVES OBTAINED FROM DIFFERENT STATES IN 1913

AND 1914
ABRASIVES
prized for this
West
purpose.
287
Virginia also contributes to the
output.
Pulpstones, which have a diameter of 48 to 56 inches, a thickness
of 16 to 26 inches, and a weight of 2300 to 4800
pounds, are a thicker
variety of grindstone.
They are used for grinding wood pulp in
paper manufacture, and hence have to withstand continual exposure to hot water. On account of their superior quality, pulpstones from Newcastle-upon-Tyne, England, supply most of the
American demand; but it is probable that certain beds of the Ohio
sandstones will be found suited for this purpose (2).
Whetstones, Oilstones (2, 13, 17), etc.

includes those stones used for sharpening
when
being often applied
The term
tools, the
"
term
whetstone
"
oilstone
''
"
placed on the stone to prevent heating and clogging of the pores by grains of steel.
The stones used
for making whetstones are either
or
sedimentary
metamorphic in
oil is
and include sandstone,
quartzite, mica schist, and novacselected will naturally vary somewhat with the
exact use to which it is to be put, but even texture and compara-
character,
ulite.
The stone
A small amount of clayey matter

tively fine grain are essentials.
adds to the fineness of grinding, but an excess lowers the abrasive
In the schists used, abrasive action is due
efficiency of the stone.
to the grains of quartz, or sometimes garnet, which are
among the fine-grained scales of mica.
Rocks suitable
embedded
whetstone manufacture are found in many

on account of
keen competition and limited demand, only the better grades from
for
states, especially east of the Mississippi (2, 13), but,
the best-located deposits are employed. Most of the supply is

therefore obtained from a few states, especially Arkansas, Indiana,
Ohio,
New
York, Vermont, and
New
Hampshire.
Among the whetstones quarried in the United States, the Hindostan or Orange stone of Indiana and the Deerlick oilstone of Ohio are
much used for oilstones.
in Grafton County,
At Pike
Scythestones are made from schistose rock

and Orleans County, Vermont.
New Hampshire,
Station,
N. H. (PL XXVI,
Fig. 2), the
raw material
quarried for scythestones is a fine-grained, thinly laminated, micaceous sandstone, whose quartz grains occur in definite layers, separ-
ated by thin layers of mica flakes. Those portions of the rock

in which the quartz grains are coarse or irregularly disposed, as well
1
as argillaceous portions, are unfit for abrasive purposes.
The novaculite quarried
in
Garland and Saline counties, Arkan-
sas (17), represents a unique type,

1
Min. Res., U.
S.
much
prized for high-grade
Geol. Surv., 1908.
ECONOMIC GEOLOGY
288
and in demand both at home

an extremely fine-grained sandstone made up of
oilstones for sharpening small tools,
and abroad.
FIG. 94.
It
is
North-south section through Missouri and Statehouse Mountains show-
ing folded character of novaculite and slate-bearing formations of Arkansas,
Bigfork chert;
novaculite;
e.
b.
Stanley shale.
a.
Missouri Mountain slate; d. Arkansas

(After Purdue, Ark. Geol. Surv., 1909.)
Pclk Creek shale;
c.
under the microscope. The

and has a conchoidal
fracture.
While the deposits, which are stratified, have a total
thickness of over 500 feet, the commercial novaculite is found only
in thin beds varying from a few inches to 15 feet in thickness.
The
and Fig. 94), and are cut by sevbeds have a steep dip (PI.
eral series of joints, which greatly interfere with the extraction of
There are also
large blocks, and sometimes even with small ones.
structural irregularities and almost invisible flaws, so that much
waste is caused in quarrying the rock. The rock has been variously
finely fragmental quartz grains, visible
rock
is
chertlike in superficial appearance
XXX
regarded as a metamorphosed chert, a siliceous
silt,
or a silicified
limestone.
Pumice and Volcanic Ash.
The term
"
pumice," as used in
the geological sense, refers to the light spongy pieces of lava, whose
peculiar texture is due to the rapid and violent escape of steam
from the molten lava. It is put on the market either in lump form,
or ground to powder, or in com-
pressed cakes of the ground-up

In the commercial
material.
"
"
insense the term
pumice
cludes volcanic ash (Fig. 95) as
well as true pumice.
Most of the pumice used in
the United States
is
obtained
from the island of Lipari, north

of Sicily. The stone, after being
freed from the volcanic ash with
which
FIG.
95.
ash from Madison

(After J. P. Rowe.)
Volcanic
County, Mont.
it is
mixed,
is
sorted ac-
cording tocolor, weight, and size,

~
,
.,
before it is shipped to market.
,
PLATE
XXX.
View
in
Arkansas novaculite quarry.
(Photo, loaned by Pike Maniir
facturing Co.)
(289)
ECONOMIC GEOLOGY
290
Deposits of volcanic ash are abundant in

for example, in
Nebraska
(10),
Utah
(13),
many
western states,
Montana
(14),
Oregon
Colorado (15), etc., but owing to their inaccessibility these materials cannot compete with Lipari pumice, which
is imported as ballast, and sells in its prepared form for 2 to 2^ cents
per pound. The pumice produced in the United States in 1913
came from Kansas, Utah and Nebraska. The deposits are very
abundant in the last named state, as Barbour remarks that nearly
the whole of it is underlain by pumice beds as far east as Omaha.
This material has been used to some
Diatomaceous Earth. 1
extent for abrasive purposes, either in the form of polishing
powder or in scouring soap. Since it has many other and more
important possible applications, it is described separately on a
(12),
Wyoming
(ll),
later page.
Tripoli.
and sold as
(See p. 412.)
Some
tripoli flour,
whose value
of the Missouri tripoli

f.o.b. is
is ground
$6-$7 per ton. This
employed as an abrasive for general polishing, burnishing,

burring, as \vell as an ingredient of scouring soaps.
The so-called " silica " obtained in Union County, Illinois, is
similar to tripoli, and may have had the same origin.
Both of these run high in silica, and in that respect are different
from a so-called tripoli, obtained in Johnson County, Tenn., and
representing a leached Cambrian limestone. It carries about 68
flour is
and
per cent
silica (Ref. p. 414).
Crystalline Quartz
(2, 13).
Some
of the vein quartz quarried
United States, and also quartzite, is pulverized and used for

abrasive purposes.
Considerable quartz sand is employed by
stone cutters as an abrasive in sawing stone, and a small quantity
in the
utilized in
making sandpaper. (See further, p. 390.)

This also is used to a small extent for abrasive
Feldspar (13).
it
but
since
has other and more important uses it is dispurposes,
cussed separately on p. 321.
The garnet group includes several mineral
Garnet (13, 16).
is
which are essentially silicates of alumina with iron or lime,

magnesia, manganese, and chromium. They crystallize in the isometric system, have a hardness of 6.5 to 7.5 and a specific gravity
Their color is variable, but commonly a shade
of 3.55 to 4.30.
The two commonest species are Almandite
of red or brown.
and
Grossularite
4
[Ca 3 Al 2 (SiO 4 )3].
3
Al2(Si0
)3]
{Fe
species
Infusorial earth
earth.
Both are
and
tripoli are
incorrect.
terms sometimes
applied to Diatomaceous
ABRASIVES
Garnet
is
Garnet
is
291
common
mineral in many metamorphic rocks, and

a
subordinate
constituent of these, it may in
though ordinarily
some cases become the chief one.
an abrasive because of
of value as
ness and cleavage.
The
best material
is
its hardness, toughthat which is well crys-
and relatively free from impurities, for it has greater

strength and stands up better under conditions of service than
finely granular material, or that containing inclusions of other
tallized
The common
impurities found in garnet are hornThe parting or imperfect

cleavage which garnet possesses causes it to break with smooth
surfaces and sharp edges, the latter adding to its abrasive
minerals.
and pyroxene.
blende, chlorite, mica,
value.
Although garnet
is
common
mineral in
many metamorphic
rocks, especially gneisses and schists, few deposits of economic

value are known, and in the United States the most productive
deposits are found in the Adirondacks, while others are

in New Hampshire and North Carolina.
New
worked
York (16, 16a)

The garnet industry is an important one
Adirondack region, a steady production having come from
Warren and Essex Counties. The garnet, which is Almandite,
.
in the
may
occur in several different ways,
in Grenville gneisses,
of the
metamorphism
3. As
intrusive rocks.
viz.:
and representing a
of sediments;
large,
more or
2.
As
1.
crystals or grains
crystallization product
As
less
distinct crystals in
rounded masses with
hornblende reaction rims, occurring in long, lens-like

inclusions of Grenville hornblende gneiss in sjênite or granite;
4. As more or less distinct crystals, without hornblende rims, in
a certain special basic syenite like an acidic diorite-like rock.
distinct
At the
largest
gneiss mined.
mine the garnets form 7 to 8 per cent of the

is crushed, and the garnet concentrated
The rock
and pneumatic separators.

Garnet is also produced in New Hampshire
In the former state, the rock quarried
Carolina.
and
North
(I5o)
at Wilmot consists of garnet, biotite, quartz and albite, of which
by
jigs
Other Localities.
first named forms about 60 per cent.

Some garnet has been imported from
the
Spain, and is said to be

obtained by washing the sands of certain streams in the province
of Almeria.
Garnet is used in the manufacture of garnet paper,
Uses.
being a valuable abrasive for leather and wood. It has also been
ECONOMIC GEOLOGY
292
employed
made
in polishing and grinding brass.

Attempts have been
it as a substitute for corundum in the manufacture of
to use
emery wheels,
although
for,
having a splintery
smooth.
softer, it possesses
fracture,
Corundum and Emery
which prevents
(3-9).
Corundum
the advantage of
it
(A12
from wearing
3)
is,
next to
diamond, the hardest of the natural abrasives known, having a

hardness of 9, but varying slightly from this.
Its fracture is irregular to conchoidal,
and gives a good cutting
A
surface, but the presence of parting planes decreases its value.
it
4
to
from
other
of
distinguish
helps
light-colored
specific gravity
minerals found in the
variable behavior
when
corundum regions. Corundum shows a

heated, some forms crumbling when ex-
posed to a high temperature. Such kinds are worthless for the

manufacture of emery wheels, all of which must be fired in order to
fuse the clay bond used in their manufacture.
Nearly all corundum analyses show SiO2 Fe 2 3 and H 2 O, and it

must be remembered that in analyses of commercial corundum
the alumina percentage does not indicate the quantity of corundum
present, as some of it may belong to aluminous silicates.
,
The
following analyses represent selected rather than commercial
samples:
ANALYSES OF CORUNDUM
ABRASIVES
A number
of other minerals
may
293
be associated with
it
as follows (5):
Associated minerals.
and
In gneiss
zircon, rarely
granite:
Besides
essentials,
garnet magnetite,
pyrite t
monazite and sodalite.
In peridotites and other basic rocks: Olivine, magnesian amphibole,

pyroxenes, rarely plagioclase; chromite and spinel, accessory primaries.
In contact zones: Corundum, biotite, muscovite, garnet, staurolite,
tourmaline, rutile, etc.
In regionally metamorphosed rocks: biotite. muscovite, amphibole,
silli-
manite, cyanite.
With the exception of a few localities in Monand one or two in California,
Distribution.
tana, two
in Colorado, one in Idaho,
the
known United
States
occurrences
all
are confined to the
Appalachian region,
commercially
the
valuable deposits for

abrasive
purposes
being found in a belt

of
basic
magnesian
rocks,
extending
from Massachusetts
to
Alabama.
These
their
velopment
in
Carolina
(5)
Georgia
of the
reach
rocks
greatest
de-
North
and
Section showing occurrence of corundum

around border of dunite mass.
(After Pratt,
FIG. 96.
Most
(3).
corundum is
U. S. Geol. Sun., Bull. 180.)
found there, in peridotite, especially near its contact with the

surrounding gneiss.
It is believed that the corundum which was one of the earliest
minerals to crystallize out from the cooling peridotite was concentrated around the borders of the mass by convection currents. This
zone of corundum sent off tongues toward the interior of the mass,
and now that erosion has removed the main zone of corundum,
these tongues remain as apparently separate veins within the peridotite (Fig. 96).
the greatest development of corundum is in a belt
is also found east of the Blue Ridge.
Georgia
at Pine Mountain,
(3) contains scattered deposits, the most important being
Rabun County. Some mining has been done in South Carolina and Geor-
In North Carolina
in
Macon County.
(5)
Some
ECONOMIC GEOLOGY
294
gia,
and deposits
in garnetiferous
mica schists cut by granite have been
recorded from Patrick County, Virginia (9).

No corundum production is recorded in the United States since 1906.
in Canada (2a).
Important deposits of this mineral
worked at Craigmont, Ontario. The northern part of this
hill is composed of granite gneiss of the Laurentian batholith,
which appears to merge into the overlying corundum-bearing
This latter
series that forms the summit and southern slope.
Corundum
are
complex of different but closely related rock types

representing differentiation products of one highly alkaline and
aluminous magma, containing nepheline. These rocks are intersected by syenite pegmatite, which contains the largest and most
abundant crystals and masses of corundum. These dykes sometimes attain a width of 18 feet, and usually run parallel with the
series is a
foliation of the series.
Emery.
This
is
a mechanical mixture of corundum, magnetite
or hematite, and sometimes spinel.

Feekskill, New York (6-8), is
now the most important sources of production, Massachusetts
having discontinued.
/
At the former locality, the deposits which lie southeast of the town,
and were first opened for iron ore, occur along the contact of basic intrusions
belonging to the gabbro series. The emery deposits, according to G. H.
Williams, are simply segregations of the basic oxides in the norite, and the
ore is made up of corundum, magnetite, and hercynite (an iron-aluminumIn some specimens the corundum forms over 50 per cent of the
spinel).
mass, while in others the hercynite may make up nearly 100 per cent of it.
The Peekskill material is very serviceable when made into wheels with a
bond. The following are analyses of it.
ABRASIVES
2P5
while the emery streak in it averages about 6 feet, it being bordered

by chlorite seams. The emery is in pockets, but these are
traceable by a small vein of chlorite. The Massachusetts output has been
or 12
feet,
on both
sides
diminishing and none has been reported since 1912.
After mining, both corundum and emery need to be cleaned and

concentrated by special mechanical processes. The chief use of
an abrasive, and for this purpose it is used in the

and blocks, emery paper, and powder.
Practically all the corundum and emery used in the United
The emery is imported crude as ballast from
States is imported.
Turkey and Greece. Corundum is imported mainly from Canada
this material is as
form
of wheels
in pulverized form.
Black diamonds, known as borts and carbonados,

Diamonds.
which are of no value for gem purposes, are much sought after for
use in drilling, being set in the end of the cylindrical drill tube.
They are often of rounded form, translucent to opaque, and lack
the cleavage possessed by the gem diamonds. Brazil, Africa,
Borneo and India serve as sources of supply, but the first-named
said to yield the best ones.
The ordinary sizes for drills
1 carat, but in special cases pieces weighing 4 to 6
carats are used.
The price ranges from $50 to $75 per carat.
country
is
-weigh from % to
Diamond powder is also used as an abrasive for cutting other

diamonds, gems, glass, and hard materials which cannot be cut by
softer and cheaper substances.
These are used for grinding
Pebbles for Grinding (23-25)
.
minerals, ores, cement clinker, etc., and those employed in the

United States have been chiefly flint pebbles obtained from the
chalk formations of
Denmark and
France, but not a few have been
imported from other foreign countries. The value of flint pebbles

lies in their hardness and uniform character; moreover, they contain little else but silica, and hence there is little danger of the
material worn
example
in
off
the ground product, as for

which must be free from iron
contaminating
grinding
feldspar,
oxide.
The decrease in foreign supply, due to the European war, has

stimulated search for domestic sources of supply with some
Pebbles of granite and quartzite have been imported
results.
into the United States from Newfoundland and Ontario for some
Stream pebbles of
and similar ones could be found here.
in
California
tried
been
gold mills; dense silicified
quartz have
time,
ECONOMIC GEOLOGY
296
rhyolite has given satisfactory results in some of the metallurgical

mills of Nevada, and basalt has been tried in Oregon.
Artificial
Abrasives.
much manufactured.
which
Several
artificial
abrasives
Prominent among these
are
now
carborundum,
furnace of a mixture
is
produced by fusion in the electric

and sawdust; the reaction beingSK)2+3 C = CSi
+2 CO. The sawdust is added to give porosity to the mixture.
Other forms of carborundum are aloxite and samite.
Artificial corundum or alundum, whose introduction is of more
is
of silica, coke,
is made by fusing bauxite in the electric furnace.

It is
put on the market in the form of wheels, etc., while carborundum
Borois either made into wheels or sold in powdered form.
recent date,
carbone is similar to alundum.

The value of the abrasives proProduction of Abrasives.
duced in the United States during the last five years, together
with the imports and artificial abrasives, was as follows:
VALUE OF ALL ABRASIVE MATERIALS CONSUMED

1910-1914
KIND OF ABRASIVE
IN THE UNITED STATES,
ABRASIVES
297
9a.
emery.) 9. Watson, Min. Res. Va., 1907.
(Va. corundum.)
Sloane, S. Ca. Geol. Surv., Ser. IV, Bull. 2: 150, 1908.
(S. Ca. corDiatomaceous Earth: See references on p. 318.
Pumice
undum.)
and volcanic ash:
10.
Barbour, Neb. Geol. Surv.,
I: 214, 1903.
lOo.
11. Barton
Surv., Bull. 13, 1914.
(Okla.)
and Siebenthal, U. S. Geol. Surv., Bull. 364: 65, 1907. (Wyoming.)
12. Diller, U. S. Geol. Surv., Prof. Pap. 3: 40, 1902.
13.
(Oregon.)
Buttram,
Okla.
Geol.
Merrill, G. P., Non-metallic Minerals,
New
and Hewett, Min. Res. Ore:, I, No. 6:

14. Rowe, Bull. Univ. Mont., No. 17, Geol.
15.
Woolsey, U.
-Garnet:
York, 1904.
72,
Ser.
1914.
No.
1,
13o. Pardee
(Vole, ash, Ore.)
1894.
(Montana.)
Geol. Surv., Bull. 285: 476, 1906.

(Colorado.)
15o. U. S. Geol. Surv., Min. Res., 1913: 266, 1914.
16.
S.
Newland, N. Y. State Mus., Bull. 102: 70, 1906. (New York.) Also
Ref. 13.
16a. Miller, N. Y. State Mus., Bull. 164: 95, 1913, and
Econ. Geol. VII: 493, 1912. (N. Y.)
Whetstones, Grindstones,
and Millstones: 17. Griswold, Ark. Geol. Surv., Ann. Rept., 1890,
18. Grimsley, W. Va. Geol. Surv.
(Ark. novaculite.)
III, 1892.
IV: 375, 1909. (Grindstones.) 19. Kindle, Ind. Dept. Geol. 'and
Nat. Res., 20th Ann. Rept.: 329, 1896. (Indiana.) 20. Nason, N.
Y. State Geol., 13th Ann. Rept., I: 373, 1894. (N. Y.) 21. Newland,
N. Y. State Museum, Bull. 102: 110, 1906. (N. Y.) 22. Watson,
Min. Res. Va.: 401, 1907. (Grindstones.)
Tripoli: See references,
Pebbles: 23. Carpenter, Min. and Sci. Press, Jan. 23, 1915.
p. 414.
(Danish and substitutes.) 24. Eckel, Ibid., Jan. 16, 1915. (Tube
mill pebbles.)
25. Anon., Ibid., Feb. 13, 1915. (Substitutes for Danish
pebbles.)
CHAPTER X
MINOR MINERALS. ASBESTOS
Asbestos Minerals (l, 13).
The minerals which have been
mined and sold under this name include: Chrysotile, the fibrous
form of serpentine (H4Mg 3 Si20g), Actinolite [Ca(MgFe)3(SiOa)4],
and Anthophyllite (MgFe) Si0 3
Crocidolite (NaFeSi 2 O 6 FeSiO 3 )
.
is
also
The
mentioned by some.
following table gives the chemical composition of the
different ones:
ANALYSES OF ASBESTOS MINERALS
MINOR MINERALS
2.
Slip fiber
to the walls.
3.
Mass
This
It
fiber
299
lying in slipping planes with the fibers parallel

may be either chrysotile or amphibole.
with the fiber occurring in bundles or groups.
always anthophyllite.
Of the three asbestos minerals,
Comparison of Types.
and anthophyllite next. The
most
the
is
important
chrysotile
commercial value of asbestos depends on the fineness, length,
Chrysotile asbestos is
flexibility, and strength of its fiber.
is
FIG. 97..
Map
showing asbestos
districts of the
United States.
(After Diller,
U. S. Geol. Surv., Min. Res. 1913.)
Thetford, Que., chrysotile; 3. Rocky Mount, Va.,

Mountain, Ga., anthophyllite; 5. Llano, Tex.
and Globe,
amphibole; 6. Casper Mountain, Wyo., chrysotile; 7. Grand Canyon,
Ariz., chrysotile; 8. Kamiah, Ido., anthophyllite; 9. Towle, Calif., amphibole.
1.
2.
Lowell, chrysotile;
Amphibole
slip
fiber;
4.
Sail
it in
generally taken as the standard. Anthophyllite equals
but
is
far
resistance to acid, heat, and insulating properties,
and
tensile
strength.
inferior in regard to flexibility, fineness of fiber
Crocidolite
but equals
is inferior
it
to chrysotile in
its fire-resisting
properties,
in other respects.
mode of occurrence is cheaper to

latter forms but a small perthe
mine than chrysotile, since
has to be crushed and freed
and
rock
mass,
centage of the entire
Canadian extraction as
the
from impurities. Hopkins gives
Anthophyllite because of
6.45 per cent
and that
its
of Georgia as
90 to 95 per cent.
ECONOMIC GEOLOGY
300
in the United States.

The ancient crystalline
which the famous Quebec deposits occur, extend
southwestward through the eastern states, as far as Alabama,
and while a number of small deposits of asbestos are known,
yet nowhere are there any large ones, moreover, most of the
Distribution
rocks
in
deposits are of the amphibole type.
Vermont
The only
(8,9).
in Lamoille
chrysotile deposit
worked
in the
and Orleans
counties, Vermont, where

found occupying a rather limited area in a large
Two types of chrysotile are found, one formserpentine area (9)
eastern belt
the material
is
is
FIG. 98.
Asbestos vein in serpentine.
(Photo, by G. P. Merrill.)
ing branching veins similar in character and quality to the Canadian fiber, the other, of inferior quality, occurring as short fibers on
slickensided surfaces.
In 1908 a mill was erected near Lowell,

had up to 1913
for separating the fiber, but the district

not entered the list of steady producers.
Vermont,
Sail Mountain, Georgia, has been the main

Georgia (4).
source of supply of asbestos in the United States for some years.
The
anthophyllite forms lens-shaped masses in peridotites and

pyroxenites, which are associated with pre-Cambrian gneisses,
the largest lens exploited being 70 by 50 by 50 feet. The fibers
are If inches or less in length, but break into shreds of j to TV
inch.
Pyrite, magnetite, talc, calcite and dolomite are the im-
MINOR MINERALS
purities.
by the
It is
301
supposed that the anthophyllite has been formed
and enstatite of the igneous rocks.

hydration and oxidation both the anthophyllite and any
unaltered olivine may be converted into serpentine, and the latter
alteration of olivine
By
partly into talc.

The rock is crushed, fiberized and screened, the product being
used chiefly as a cement for boiler covering.
FIG. 99.
Geologic
map
of
Vermont asbestos
Amer., Bull.
XVI,
area.
(After Marsters, Geol. Soc.
1905.)
Amphibole asbestos is found in slip-fiber veins near

Virginia (2, 16).
Bedford, Va. The prevailing rock, which consists of hornblende and olivine,
or in some cases pyroxene and olivine, is cut by occasional shear planes
along which the slip fiber has developed.
Asbestos was discovered about 25 miles northeast of
Arizona (2).
It forms cross-fiber veins in limestone, overlying diabase,
in 1913.
the higher-grade veins being associated with a diabase dike.
Somewhat similar is the occurrence in the Grand Canon of the Colorado
Globe
River, near Grand View, where the asbestos forms veins in a serpentinous
Diller has suglayer, enclosed in limestone, not far from a diabase sill.
gested that the serpentine is derived from some mineral in the limestone,
ECONOMIC GEOLOGY
302
while the asbestos veins post-date the serpentine, and
may represent a phase

metamorphism.
Near Kamiah, the anthophyllite asbestos forms ledges,
Idaho (2).
within mica schist, and may represent an altered intrusive. It is shipped
to Spokane, Wash., where it is sawed up and also ground.
South and southeast of Casper are pre-Cambrian inWyoming (2).
trusives consisting of hornblende schist, diorite, granite and serpentine,
the last-named being much crushed and sheared, and containing both cross
and slip-fiber veins of chrysotile.
of contact
Precambrian
|
Palaeozoic
M Asbestos and
HChromite Rock*
SCM.L OF Mats
FIG. 100.
Map
of
Quebec asbestos
area.
(After Dresser, Can.
Min.
Inst.,
Trans. XII.)
is
The main source of the world's supply

Quebec, Canada.
obtained from southern Quebec, and as it is the best known
occurrence
The
it
may
be properly referred to here.
geologic relations (Fig. 100) of the serpentines and associated rocks are imperfectly known, but it appears certain that they
PLATE XXXI.
General view of asbestos quarry, Thetford Mines, Que.

(H. Ries, Photo.)
(303)
ECONOMIC GEOLOGY
304
represent a series of stocks and
sills,
cutting rocks of Cambrian,

of the asbestos belt are
The rocks
Ordovician and Silurian age.
generally much altered to serpentine; pyroxenite,

to talc; gabbro; diabase; and a breccia, in
altered
frequently
part of volcanic material.
peridotite,
The serpentine is an alteration product of peridotite, it and the

pyroxenite being of laccolithic character, while the granite, which
Photomicrograph showing vein of asbestos (a), with irregular margins,

and mid streak of magnetite (6). Serpentinized rock (c) on either side.
FIG. 101.
(After Dresser, Can. Geol. Sun.,
Mem.
forms dikes and isolated masses,
22.)
may
be a final and extremely acid
product of differentiation of the general magma of which the basic

equivalent is the olivine-rich portion of the peridotite.
The asbestos is found forming veins in the serpentine, the width
of these varying from a mere line to two or three inches.
It develin
in
first
and
afterwards
other
oped probably
joint planes,
cracks,
forming thus a network (Fig. 102). An interesting and suggestive

is the band of pure serpentine on either side of the vein
feature
(Fig. 102), the ratio of the asbestos vein to the entire
pentine and asbestos being
6.6.
The
band
veins are formed
of ser-
by the
&7
s
**
3
cr
(H
03
a
""
ft
M g
s-l
(305)
ECONOMIC GEOLOGY
306
growth of minute crystals of chrysotile, perpendicular to the walls,

and there is in most cases a central parting marked by a film of
chromite or magnetite. The principal mines are near Thetford
Mines (PL XXXI), Black Lake, East Broughton, and Danville.
The first-named
locality
Peridotite
is
of great importance.
Asbestos
Serpentine
FIG. 102.
s>coje.
Diagram showing asbestos and serpentine
MM
The largest vein
iwo inch3S via,.
in peridotite.
la
(After Dresser,
Econ. Geol, IV.)
The asbestos milling rock forms from 30 to 60 per cent of the

quantity quarried, and 6 to 10 per cent of this is fiber.
There has been some difficulty in explaining satisfactorily the
origin of the chrysotile veins in serpentine, for
quite different
we have
here two
forms of the same mineral.
to explain the origin of the vein
filling,
Pratt, in attempting
believes that the fissures
represent contraction cracks formed around the edge of the peridotite mass while cooling, and which were then filled by aqueous
solutions
from which the chrysotile
crystallized.
Merrill,
on the
other hand, believes the fissures to have been caused by shrinkage

incident to a partial dehydration of the rocks and subsequent filling
by
crystallization extending
suggested by
Kemp,
a loss of
from the walls inward (11, 5). As

silica may also have produced some
shrinkage.
Cirkel (1), believes the vein crevices to have been formed
by
MINOR MINERALS
partial dehydration,
and
in part
by
307
fracturing resulting from the
intrusion of the granite.

All investigators agree
on the wall rock being the source of the

while admitting the filling of the veins by
infiltration, suggests that they have been enlarged by replacement
He points out that the veins usually
of the walls (Fig. 101).
show a middle parting of ore minerals, and furthermore, that
chrysotile.
Dresser
(3),
microscopic study indicates that the fibers have grown outward

from each side of the seam of ore, indicating alteration and recrystallization
of the
serpentine
to chrysotile in situ.
It
is
furthermore
thought that the depth at which the chrysotile

formed probably precluded the existence of open fissures in which
the material could have crystallized.
It is still to be regarded as doubtful whether meteoric or magmatic water was operative in bringing about the change, although
most
geologists favor the latter.

Outside of Canada, Russia is the only other
important producer. The chief deposits are in the Urals (1) near the station
of Baskenovo, and the asbestos occurs as cross fiber in serpentine.
Other
The Russian production for 1913
deposits occur in the Orenburg district.
was 18,594 short tons. Asbestos of the hornblende variety is obtained in
Crocidolite has been mined in West
Italy, but the production is small.
Griqualand, Africa, but the industry has not been established on a per-
manent
basis.
The usefulness of asbestos depends

Uses of Asbestos.
mainly on the flexibility of its fibers, and fibrous structure, and to
a less extent on its low conduction of heat and electricity, and on
Asbestos is used in fire-proof paints,
its moderate refractoriness.
boiler coverings, for packing in fire-proof safes, and for electric insulation where some heat resistance is necessary.
Chrysotile is
also used in making fire-proof rope, felt, tubes, cloth, boards,
Asbestic is a name given to short-fibered chrysotile
blocks, etc.
mixed with serpentine. Asbestine is a pigment of which asbestos is
an important ingredient, and serves to hold up other heavier pigments. Asbestos is also used for filtering in chemical work, and
for this purpose the amphibole asbestos is better adapted.
Many
patented mixtures of asbestos and other materials, such as Port-
land cement,
etc.,
are
now used
for
making such products as
asbes-
wood, asbestos slate, asbestolith, etc. Asbestos roofing tile,

roofing felt and shingles are now also made in large quantities.
tos
ECONOMIC GEOLOGY
308
The United States

Production of Asbestos.
producer of manufactured asbestos products, but
is
the largest
less
than one
per cent of the raw material is mined in this country. Canada is

the main source of supply, and will no doubt continue so for a long
time.
Next to Canada, Russia
much
is
the largest producer, and
United States.
The production and imports from 1910 to 1914 were as follows:
exports
of its product to the
ANNUAL PRODUCTION AND ANNUAL VALUE OF IMPORTS OF ASBESTOS INTO

THE UNITED STATES, 1910-1914
YEAR
MINOR MINERALS
309
9. Marsters, Geol. Soc. Amer., Bull. XVI:

10.
419, 1905.
11. Merrill,
Merrill, Non-metallic Minerals:
183, 1910.
(General.)
Geol. Soc. Amer., Bull. XVI: 416, 1905.
12. Pratt, Min(Origin.)
eral Census, 1902, Report on Mines and Quarries: 973, 1904.
13.
mont.)
Merrill, Proc., U. S. Nat. Mus., XVIII: 281.

(Asbestos and asbesti14. Pratt,
in. World, July 8, 1905. (Ariz.)
15. Rich-
form minerals.)
ardson, Vt. State Geologist, Rept., 1909-10; 315, 1910; Ibid., 1911-12:
16. Watson, Min. Res. Va.: 285, 1907.
(Vt.)
269, 1910.
BARITE
Properties and Occurrence.
Barite, the sulphate of barium,
contains when pure, BaO 65.7 per cent, and 80s 34.3 per cent.
Its specific gravity is 4.3 to 4.6 and its hardness 2.5 to 3.5.
It
commonly white, opaque to translucent, and crystalline,

while the texture is granular, fibrous, or more rarely earthy.
Barite is a common mineral which may be found in many kinds of
is
It has in nearly
igneous, sedimentary, and metamorphic.
cases been formed by deposition from aqueous solutions, and
rocks
all
not found as an original constituent of igneous rocks, nor in

contact metamorphic zones, or pegmatite veins. Furthermore
it is not a product of dynamo-metamorphism.
is
Analyses of many rocks show at least small amounts of barium,

it has also been noted in orthoclase feldspars and some
and
micas.
has frequently been found in spring and mine waters, where

be in solution as the chloride, carbonate, or perhaps even
as sulphate. 1
Contact of solutions containing the first two with
It
it
may
sulphate waters will form barium sulphate, although

may be retarded by the presence of chlorides.
tion
its
precipitaTrav'ertine
deposits containing varying amounts of barite are also known,

one described from Doughty Springs, Colo., showing from a
small percentage up to 95 per cent 2 barium sulphate.
These facts indicate that barite is deposited from

and probably most deposits are formed in this manner.
Form
barite
I.
of
may
Commercially
Deposits.
include the vollowing types:
Veins formed by the
by cementing
filling of
important
fissures,
solution,
deposits
of
by replacement, or
of fault breccias, the wall rocks being lime-
Barium sulphate has a solubility of 1 part in 400,000 of water, but the natural
compound is said to be six times more soluble than the artificial.
2
Headden, Col. Sci. Soc., Proc., VIII: 1, 1905.
1
ECONOMIC GEOLOGY
310
quartzite, sandstone, schist, gneiss or volcanic

rocks in the different occurrences (3, 5a, 8a, ll).
stone,
II.
Bedded deposits
(so
called),
formed by replacement of
pyrite (la).
III. Irregular masses, occurring as
IV.
replacements of limestone
(ll).
in residual clays (ll).
Lumps
V. Filling the interstices of brecciated masses (ll, 12).

These vary with the indiAssociated Minerals (3, 5a, ll).
The vein and replacement types
vidual deposit.
often contain
metallic sulphides, especially galena, but sometimes sphalerite,

Galena is harmful, since it discolors the
chalcopyrite, and pyrite.
ground product, and other sulphides may cause similar trouble.

Quartz, calcite, and fluorite are also at times abundant, the last-
named
being especially noted in Kentucky and Tennessee veins

some of the Great Valley occurrences of Virginia.
Residual deposits especially may carry considerable iron and
as well as in
manganese
oxides, as well as quartz.
Small amounts of iron
oxide can be removed
by treating the ground product with H^SO.*,

but the manganese is more difficult to eliminate (ll).
Barite veins have not been sufficiently worked in the United
is much change with depth,
but this has been noted in several European ones (la)
This, in the case of
Geologic Age of Associated Rocks.
the deposits of the United States and Canada, may be briefly
States to determine whether there
summarized as
Triassic.
follows:
Virginia.
Mississippian.
Devonian.
Ordovician.
Western Kentucky.
Five Islands, N. S.
Missouri.
Central
Cambro-Ordovician.
Kentucky,
Tennessee,
Appa-
lachian Valley region of Virginia, Georgia, Alabama, Maryland,
and Pennsylvania.
Of these the deposits
of the
Cambro-Ordovician are the most
important, practically all the United States production coming

from Missouri and the Appalachian states.
The location
Distribution of Barite in the United States.
of the deposits in the eastern half of the
country
is
shown on the
map, Fig. 103, and the more important ones at least may be briefly
referred to since they represent several different types of occurrence.
Barite forms scattered deposits in Washington
Missouri (3).
and adjacent
counties,,
though many
of the occurrences are clus-
MINOR MINERALS
FIG. 103.
Map
311
Appalachian states. (After Watson and

Min. Engrs., Butt. 98, 1915.)
of barite deposits of
Grasty,
Amer.
Inst.
Dolomite
FIG. 104.
Barite veins in Potosi dolomite, southeastern Missouri.

ley,
Mo. Bur.
Geol.
and Mines, IX.)
(After
Buck-
ECONOMIC GEOLOGY
312
tered around Mineral Point, Washington County.

The material
is obtained from the Potosi
(Ordovician) limestones, in which it
occurs as replacement veins (Fig. 104) mixed with lead, or in
and drusy quartz, the whole forming a

no great depth (Fig. 105).
residual clay with chert

sheet-like deposit, at
Surface of Ground
'-'.-.'
[_
FIG.
105.
Drnsy Quartz
Clay
Chert
1^1
Dolomite
Barita
Barite deposit in residual play near Mineral Point,

(After Biirklru.
Jiff
n->ir.
Clpnl
a-nd
Mo.
Mines, IX.)
Barite occurs in many parts of the state (Fig.

Virginia (ll).
but
the
106),
industry has been confined mainly to a few localities.
The
barite deposits
may
be grouped into three areas, as follows:
Deposits of the Triassic red shale-sandstone series, in which the

It has
barite is associated with red shales and impure limestones.
1.
been deposited from solution in fractures in the red
SKETCH MAP OF
FIG. 106.
Map
shales, or
VIRGINIA
of Virginia
showing location
(After Watson,
of
Min. Res. Va.,
worked areas
1907.)
of barite.
MINOR MINERALS
313
more
rarely as thin, tabular replacement masses in the limestone.

Deposits of the crystalline metamorphic area, probably for the
most part of pre-Cambrian age, and in which the barite occurs either
as irregular lenses
2.
of 100-200 feet di-
ameter
in
lime-
stone, or as nodules
in a residual lime-
stone-schist clay
In one
(Fig. 107).
locality
fills
the barite
a vein in
ceous
sili-
re-
schists,
mote from
calcare-
ous rocks.
3.
The
mountain region
southwestern
ginia.
barite,
of
Vir-
FIG. 107.
Here the
which is
Ideal section in Bennett Barite Mine, Pitt(After Watson, Min. Res.
sylvania County, Va.

Va., 1907.)
associated with the Shenandoah limestone (Cambro-Ordovician),

found either as lumps in the residual clay, or in the fresh rock.
is
The frequent
areas
is
association of the barite with limestone in
all
the
quite noticeable.
The second region is the most important producer.

Watson believes that the source of the barite is the rocks in
which the deposits are now found. Thus in the Valley region it
was no doubt derived from the Shenandoah limestone, while in
the Piedmont area it may have come either from the crystalline
schists or limestone mass.
That of the Thaxton area was doubtless obtained from the silicates of the granite.
The liberation and
removal of the barium in solution
complished by shallow circulations.
is
considered to have been ac-
The
barite
is
always crystal-
line in texture.
The vein type of occurrence is well

Kentucky (5a, 8, ll).
developed in this state, there being two areas. Those veins
in the central part of the state (Figs. 108, 109) are confined to
the Ordovician, and are found filling simple fissures, or fault frac-
tures, the chief associates being calcite, fluorite, sphalerite and

galena.
They are from 1 to 3 feet in width, with a maximum of
24
feet,
and have been mined
western area, fluorspar
is
In the
to depths of 100 to 325 feet.
secondof
barite
the chief mineral, with
ECONOMIC GEOLOGY
314
FIG. 108.
Map
of barite veins near Lexington,
4th
ser., I:
mm
Barytes
FIG. 109.
Fluorspar
Sections of a
Ky.
(After Fohs,
Ky. GeoL SurvS,
441, 1913.)
Calcite
Kentucky
E53
Limestone
barite vein.
(After Fohs.)
MINOR MINERALS
ary
importance,
and the
veins
315
occurring
in
Mississippian
limestone.
Barite deposits are known to occur near
Georgia (6).
Cartersville,
Ga., associated with the Beaver (Cambrian) limestone and Weisner (Cambrian) quartzite (Fig. 110).
It is thought that the barite was originally deposited
by the replacement of cer-
tain beds of the shaly lime-
stone overlying the quartzbut it now forms nodules
ite,
\,
;
andmasses scattered through

a residual clay, and mixed
with some quartzite fragments. Gravity has probably aided in concentrating
the barite into workable
Ig^v
Quartzite
Shaly limestone
Sketch section showing relations of

barite and limonite to underlying formations
near Cartersville, Ga.
(After Hayes and
Phalen, U. S. Geol. Surv., Bull. 340.)
FIG. 110.
deposits.
Other
The
Occurrences.
barite
County,
of
North
Gaston
Carolina,
occurs as lenticular fissure

sphalerite,
associated with quartz, galena,

South Carolina is in similar
either in residual clay overlying the Knox dolo-
fillings in schist,
and pyromorphite, while that
of
that in Tennessee is
mite (Cambro-Ordovician) as in the Sweetwater
rocks;
schist, as in the
French Broad
district (7, 11).
ANALYSES OF BARITE
district,
or as veins in
ECONOMIC GEOLOGY
316
The only productive district is at Lake

(8a, 12).
Cape Breton, where barite is found in veins in the preCambrian felsite. Calcite and fluorite are occasional associates.
Canada
Ainslie,
Other veins are found
in schists of the
Louisburg shale formation
North Cheticamp.
Near Five Islands, Nova Scotia, barite has been found filling
fissures and brecciated zones in Devonian slate and quartzite,
but the deposits have not been worked steadily. The barite here
is believed to have been deposited by vadose waters, as small
amounts of it are shown to occur in the surrounding rocks.
at
Barite deposits are widely distributed, but

are probably the most important.
They include:
curious bituminous barite deposit, near Meggen, Westphalia, supposed
those of
1.
Germany
(la)
have originated by the replacement of portions of a bedded Devonian

2. Vein deposits closely assopyrite which in turn grades into limestone.
ciated often with the Permian, and showing a considerable variety of metallic
to
The barite is of higher grade than the Meggen product. Among

minerals.
other European deposits may be mentioned the replacement ones in Carboniferous limestone of Belgium, as well as minor vein deposits of France,
Italy, Austria,
and Great
Britain.
Origin of Barite.
Sulphate of barium is but slightly soluble,
but is perceptibly decomposed by a dilute solution of carbonated
If present in one of the silicates (feldspar) in granite it
be
decomposed by sulphates of the alkalies, lime sulphate,
might
alkali.
or
magnesium sulphate,
resulting
in
precipitation
of
barium
sulphate.
Buckley (3) believes that the Missouri barite was possibly derived from solutions of the bicarbonate, precipitated with alkaline
sulphates.
AVatson
(ll)
suggested that in the case of the Virginia barite
it
was probably taken into solution as the soluble bicarbonate, and

precipitated under favorable conditions as the insoluble sulphate.
Laboratory experiments by Dickson (4) with solutions of barium
carbonate on selenite crystals and pure anhydrite in presence of
C02, and on pyrite crystals in presence of an oxidizing agent,
water, caused precipitation of barium sulphate in each case.
Barite deposits
Mining, Preparation, and Uses (9a, ll).
may be worked by open cuts, shafts or pits. The greatest depth
reached in mining
The removal
1
is
probably not over 200 feet.

from merchantable barite includes
of impurities
Dammer und
Tietze,
Nutzbaren Mineralien,
II:
7,
1914.
MINOR MINERALS
317
hand cobbing,
sorting or grading, washing and crushing.

Ground
barite requires bleaching with
sulphuric acid to remove iron, dry-
ing and grinding.

Since the barite deposits are usually small and
pockety, the mill
must be located to permit its drawing on numerous and
changing
sources of supply.
Washed barite is used in the manufacture of paper, for coating
canvas ham sacks, in pottery glazes, and in the manufacture of
barium hydroxide. Its main use perhaps is in white pigments to

mix with white lead, zinc white, or a combination of both of these
formerly regarded as an adulterant of
considered to make the mixture more
permanent, less likely to be attacked by acids, and freer from
discoloration.
Lithophone paint is a mixture of barium sulphate
pigments. Although
white pigments, it is
now
(68 per cent), zinc oxide (7.28 per cent),
and
zinc sulphide (24.85
per cent).
Barium hydrate
is
used chiefly in the beet-sugar industry;
barium chloride in the color industry and the manufacture of

wall paper; barium carbonate as a chemical reagent, in glass
manufacture, and to prevent scumming of clay products. Other
uses are in the manufacture of rubber, asbestos, tanning leather,
enameling iron and oilcloth, poker chips, boiler compounds,
hydrogen peroxide, etc.
Production of Barite.
The production of barite for several
years is given below.
insecticides,
PRODUCTION OF CRUDE BARITE IN THE UNITED STATES, 1912-1914,

BY STATES
STATE
ECONOMIC GEOLOGY
318
Imports.
The imports
were as follows
of
barium compounds for 1912 to 1914
VALUE OF THE IMPORTS OF BARIUM COMPOUNDS, 1912-1914
MINOR MINERALS
319
tion serves to identify it at once.

Diatomaceous earth is commonly white or light gray in color, but may be brownish, dark
gray, or even black, due to the presence of organic matter.
exceedingly porous.
and water on
FIG. 111.
If pure, it
analysis, but
should show
most earths have
Diatomaceous earth from Lompoc,
little else
than
amounts
at least small
Calif.
(Calif. State
It is
silica
Min. Bur.,
Bull. 38.)
of other substances,
and some contain a

VI below).
large
amount
of clayey
impurities (see analysis
The
of
following analyses represent the composition of a
American earths
ANALYSES OF DIATOMACEOUS EARTH
number
ECONOMIC GEOLOGY
320
Diatomaceous earth occurs
as deposits of comparatively small extent in the bottoms of ponds,

lakes, and swamps, sometimes mixed with organic matter, or it may
marine origin and showing at times great

A few localities may be mentioned.
California (1, 2, 4).
Important deposits of diatomaceous earth
are known to occur at a number of points in the Coast Ranges of
California, but the most important, perhaps, are those found in
form bedded deposits
of
extent as well as thickness.
occurs mainly in the

Monterey (Middle Miocene) and in the lower part of the Fernando
(Upper Miocene) formations.
northern Santa Barbara County.
There
it
The
deposits range from those of high purity, through impure

shaly beds, to flinty deposits. The earth is found interbedded
with volcanic ash at some localities (south of Lompoc), and with
limestones at others.
The thickness of the diatom deposits is often
remarkable, being 2400 feet south of Harris, and 4700 feet between
the Santa Ynez and Los Alamos valleys.
New York (3, 5).

Although diatomaceous earth is known to occur
at several localities, the only one recently worked is near Hinckley, Herkimer County, where it forms a bed 2 to 30 feet in White Head Lake. It
by w ashing and pressed into cakes.
In the Atlantic Coastal Plain, deposits of diatomaceous
Virginia (8).earth are not uncommon in the Miocene (Tertiary) formations, and those
is
purified
Richmond have long been known. Along the Rappahannock

River, especially below Wilmot, there are long exposures, the bluffs of the
material standing out prominently in the sunlight.
around
Maryland.
Beds
of
diatomaceous earth occur at the base of the Calvert
formation, deposits being known in Anne Arundel, Calvert,

and Charles counties. Few of them are worked, although some attain a
thickness of at least 25 or 30 feet.
(Tertiary)
Other States.
Connecticut, Massachusetts, Florida, Nevada, and Washington are also producers, but the deposits are of limited extent.
Diatomaceous earth is known to occur at a number
Foreign Deposits.
of
Canadian
Many
localities,
deposits are
but the only production recorded

in Europe. 1
is
from Nova Scotia.
known
Diatomaceous earth, on account of its porous character,

Uses.
was formerly used as an absorbent of nitroglycerine in dynamite,
but little or none appears to be now employed for this purpose in
the United States. It can be used for polishing powders, and as a
nonconductor of heat it has been occasionally utilized for steam
boiler backing, for wrapping steam pipes, and for fireproof cement.
1
Dammer and
Tietze,
I:
202, 1913.
MINOR MINERALS
Mixed with
clay, or
partition brick or
into
even alone,
tile.
it can be used for

making porous
of the California material can be cut
used as a filter stone, or even for build-
Some
any desired shape, and
ing purposes.
321
Recently
it
has been used in talking machine
records.
In Europe, especially in
Germany, it has of late years found
extended application. It has been used in the
of artipreparation
ficial fertilizers,
especially in the absorption of liquid manures, in the

manufacture of water glass, of various
cements, of glazing for tiles,
of artificial stone, of ultramarine and various
pigments, of aniline
and alizarine colors, of paper, sealing
wax, fireworks, gutta-percha
objects, Swedish matches, solidified bromine, scouring
powders,
papier-mache, and a variety of other

large
and steadily growing demand
The production
is
articles.
for
There
is
said to be a
it.
given under Abrasives, where
it is
included
with Tripoli.
REFERENCES ON DIATOMACEOTJS EARTH

1.
Arnold and Anderson, U. S. Geol. Surv., Bull. 315 438, 1907.

(California.) 2. Aubury, Calif. State, Min. Bur., Bull. 38. 3. Cox, Trans.
N. Y. Acad. Sci., XIII 98, 1893. (New York.) 4. Fairbanks,
:
U. S. Geol. Atlas Folio, 101: 14, 1904. (California.) 5. Newland

N. Y. State Mus., Bull. 102: 67, 1906. (New York.) 6. Pardee and
Hewett, Min. Res. Oregon, I: 71, 1914. (Ore.) 7. Phalen, U. S.
Geol. Surv., Min. Res., 1908.
8. Ries, Va. Geol. Surv., Bull. II:
143,
1906
(Virginia.)
FELDSPAR
The feldspar group includes
several species, all silicates of alumina, with one or more of the
bases potash, soda, and lime. These species may be divided into
two groups,
viz.,
spars, a division
the potash feldspars, and the lime-soda feldis not without practical value, since the two
which
groups differ somewhat in their fusibility and mineral associates.

Orthoclase and microcline, whose composition is expressed by
the formula KAlSisOg, are the chief representatives of the first
Expressed in percentages their composition is SK>2, 64.7

per cent; AÔs, 18.4 per cent; KÔ, 16.9 per cent. Soda may
partly or wholly replace the potash. If the latter occurs, anorthogroup.
Potash-soda feldspars are usually pinkish to nearly

but
white,
some, as that mined in Ontario, is a distinct reddish
color.
Nevertheless, even the strongly colored ones may calcine
clase results.
ECONOMIC GEOLOGY
322
pure white color, and show a sufficiently low iron oxide

content to permit their use in pottery manufacture.
The lime-soda feldspars, or plagioclases, present a series of comto a
pounds ranging from the soda
feldspar, albite, through soda-lime

feldspars, to the pure lime spar, anorthite, at the other end.
whose formula is NaAlSi 3O 8 has SiOs, 68.7 per cent;

19.5 per cent; Na 2 O, 11.8 per cent.
Anorthite, CaAl 2Si 2 O 8 ,
has Si0 2 43.2 per cent; A12 O3 36.7 per cent; CaO, 20.1 per cent.
All feldspars in melting pass gradually from a solid condition to
Albite,
A1 2
3,
that of a very stiff fluid (5), complete fusion occurring usually

about Seger cone 9(1310C.). A mixture of soda and potash spar
seems to have a slightly lower fusing point, while the lime spar,
anorthite, does not melt until 1532 C. (5).
Most of the feldspar quarried in the United States is the potashsoda type, but in some localities the soda spar, albite, may be present.
If plagioclase is present in feldspar used for pottery, it is generally
albite.
Feldspars are widely distributed in many igneous and metamorphic rocks, but in most cases they are so intimately mixed with
other minerals, that their extraction is not commercially practicable,
and
it is
only
when found
in pegmatites that they are worked.
Of these rocks, two

matites, which are very coarse-grained
types are recognizable, viz. the granite peg-
and carry quartz, potash

tourmaline, etc., and the soda pegma-
feldspar, muscovite, biotite,

which consist mainly of albite with a little hornblende.
tites,
of the deposits
worked
in the
United States belong to the
first
Most
type,
only a few from southeastern Pennsylvania and northeastern Maryland falling in the second class.
It
may
worked
be mentioned here that
for their feldspar contents,
all
pegmatite deposits are not
some serving as sources
of other
Their value as spar dethe material present.

on
the
and
of
quantity
purity
posits depends
The pottery trade demands that the spar be free from iron-bearing
minerals, such as mica, quartz, or gems.
Muscovite is also undesirable on account of the diffiin grinding it, while the permissible limits for
encountered
culty
from
5 to 20 per cent.
quartz range
In quarrying or mining some sorting is often necessary, and in
minerals.
those states lying south of the glaciated area the deposit

capped with residual clay.
Distribution of Feldspar in the United States.
States feldspar quarries are operated in
New
may
be
In the United
York, Connecticut,
MINOR MINERALS
Maine,
deposit
Pennsylvania,
is
sylvania
and Maryland.
The
similar in all the states, but those
and Maryland are
The
wall rock
is
323
general
worked
form of
Penn-
in
albite spar, while the others

gneiss or schist.
potash spar.
In recent years feldspar deposits have also been developed
1
California, Colorado, and Minnesota.
The following table

number of localities
are
in
gives the composition of feldspar from a
ANALYSES OF FELDSPARS
ECONOMIC GEOLOGY
324
Most
Canadian production is derived from

the province
Ontario, the principal mines being located in
Frontenac County, about 20 miles north of Kingston (PI. XXXII,
The feldspar, which is often of a deep pink color and high
Fig. 2)
Canada.
of the
of
purity, occurs as veins in the
pre-Cambrian gneiss of that region.

and
veins
are
sometimes
horses
present, and tourmaline is
Quartz
While the spar veins are very abunlikewise found in patches.
all are of sufficient purity to be workable.
Other
in
been
worked
Ottawa
have
one
mine
County, Quebec,
deposits
near Villeneuve having yielded a very white albite.
dant, not
Many
for use in the pottery industry.
feldspar deposits are worked in Europe,

of Norway and Sweden are the
Those
the product being exported in considerable quantity.

mention may be made of Cornish stone, a partly weathered,
coarse-grained granite, quarried in Cornwall, England, and used in some
quantity by the potters of Europe and America.
largest producers,
In this connection
Uses (1).
Feldspar is used chiefly as a flux in the manufacture
of pottery, electrical porcelain, and some enameled wares.
For all
these purposes it should be as free from iron as possible, but some
of the
ground commercial spar
carries as
much
as 15 to 20 per cent
free quartz.
Feldspar
is
also
employed as a
flux or binder in
emery and
car-
borundum
wheels, and to some extent in the manufacture of opalescent glass.

For the last purpose it can carry more quartz and muscovite than pottery spar, and does not have to be as finely ground,
50 to 60 mesh being
As an ingredient
sufficient.
of scouring soap, feldspar possesses
advantages
over quartz, because it is softer and less liable to scratch glass.

Selected feldspar is used in the manufacture of artificial teeth.
The possibility of using feldspar as a fertilizer, because of its potash

contents, has been suggested; but no commercially practicable means
of extracting the desired element has as yet been found (2).
The production of feldspar from

Production of Feldspar.
The crude refers to that sold in
is given below.
the unground state, but all spar is crushed before use.
1909 to 1914
PLATE XXXIII
FIG.
1.
gneiss.
FIG.
2.
Stewart graphite mine, near Buckingham, Que. Rock on right, graphitic

On left at farther end of cut, a basic igneous rock. (H. Ries, photo.)
Lacey mica mine, Ontario.
(Photo loaned by Can. Dept. Mines.)

(325)
ECONOMIC GEOLOGY
326
PRODUCTION OF FELDSPAR, 1909-1914, IN SHORT TONS
YEAR
MINOR MINERALS
No.
3,
which
is less
327
carefully selected and may carry enough

it unfit for pottery
purposes.
iron-bearing minerals to render
Feldspar free from quartz is much sought after and difficult

to obtain in large quantities in the United States.
The average price in 1914 of crude feldspar used for pottery and
enamel ware was about $3.07 per short ton f.o.b. ,while the average price of the ground was about $7.40 per short ton f.o.b. mills.
REFERENCES ON FELDSPAR
1.
Bastin, U. S. Geol. Surv., Bull. 420, 1910.

2.
Cushman, U.
S.
(General and United States.)

Dept. Agric., Bur. Plant Industry, Bull. 104, 1907.
3. Day and Allen, Amer. Jour. Sci., XIX:

(Fertilizer uses.)
98, 1905.
(Thermal properties.) 3a. Galpin, Ga. Geol. Surv., Bull. 30, 1915.
(Ga.) 4. Hopkins, Ann. Kept. Pa. State College, 1898 to 1899, Ap-
pendix, Pt. II. 5. Mathews, Md. Geol. Surv., Kept, on Cecil Co.:
6. Watson, Min. Res. Va., 1907: 275.
Also forth217, 1902.
(Va.)
coming bulletin, Va. Geol. Survey.
FLUORSPAR
Fluorspar, or fluorite (CaF2 ), contains 48.9 per cent fluorine and
51.1 per cent calcium.
Its hardness is 4, its specific gravity, 3.18,
and
it
has a pronounced octahedral cleavage.
Fluorite shows a
variety of colors, including white, green, purple, etc. The mineral

is commonly found in veins which may be fissure fillings or replace-
ments, and is often associated with ore minerals, especially lead and
tin.
Limestone is the most important wall rock of the American
deposits, but in some districts granites, gneisses, or volcanic rocks
may form
the vein wall.
In the United States fluorite

found at a number of points in the Piedmont and Appalachian
areas from Maine to Virginia, and is likewise noted (usually in small
amounts) in many metalliferous veins of the west; but the most
is
important producing districts are in Kentucky and Illinois. Colorado, Arizona, and Tennessee are also to be included in the producing states.
In the western Kentucky district, which is

Kentucky (3, 4).
one of the largest producers of the world, the fluorite occurs as vein
deposits in fault fissures cutting limestones (PI. XXXIV, and Fig.
112), sandstones,
and shales
of Carboniferous age.
The minerals
ECONOMIC GEOLOGY
328
have been deposited by
(1) a filling of the fissure cavity, (2) replacing the wall rock of the fissure, or (3) cementing a breccia of the
same. Associated with the fluorspar are barite, calcite, galena,
and sphalerite, as well as other minerals in smaller amounts. The
different minerals
may
occur in the veins, either intimately inter-
or in separate bands; in
eral may be present in the vein.
grown
some
The
cases,
and northwest, but the former carry more
FIG. 112.
Section of
Memphis mine
(After Fohs,
however, only one min-
fault fissures strike northeast

fluorite.
group, along line
Ky. Geol Sun.,
SS
of PL.
XXXIV.
Butt. 9.)
supposed that the fluorite has been deposited by thermal

waters, which were given off during cooling by the dikes of mica
The fissures, fault
peridotite which are found in the district.
and
dike
contacts
served
as
trunk
channels
along which the
planes,
waters ascended, and from which they also spread out into the adIt is
jacent rocks.
fluorite.
The
Weathering has produced a disintegration of the

show a maximum width of 36 feet for gravel
veins
ore and 16 feet for
lump
ore.
The product
of the veins is divided into lump, representing the

coarse product; gravel, which is the naturally or artificially disin-
tegrated spar, and ground fluorspar. Washing and jigging are

Number 1
necessary to separate clay and associated minerals.
fluorite is usually white and carries 96 per cent or more of calcium
fluoride; Number 2 grade has at least 90 per cent calcium fluoride
and under 4 per cent silica; while Number 3 carries from 60 to 90

per cent calcium fluoride.
Until 1898 the mines of Hardin and Pope counties,
Illinois.
Illinois,
were the only domestic source
(1),
and
this area continues
MINOR MINERALS
329
to be an important producer. There the deposits

Lower Carboniferous limestones or sandstones.
fill
fault fissures
Dikes of mica
in
also
occur
the
but
in
not
contact
with
the veins.
district,
peridotite
These latter in some places attain a width of 45 feet and a proven
depth of 200 feet. This great width is due partly to enlargement of
in
by solution, and partly to a replacement of the limestone

In the limestone footwall, the fluorspar sometimes forms a
solid mass from 2 to 12 feet thick, but that on the hanging wall is
the fissure
walls.
The vein
less pure.
filling is chiefly fluorite
sociated with these are smaller
occasionally pyrite or
galena
The
is
amounts
chalcopyrite.
and
calcite,
while as-
of galena, sphalerite,
It
is
and
significant that the
slightly argentiferous.
is somewhat doubtful, but Bain (1) beprobably been derived from heated waters of either
meteoric or magmatic origin which leached the mineral from some
origin of the fluorite
lieves that it has
mass of low-lying igneous rocks of which the dikes are offThese heated ascending solutions are thought to have
carried fluosilicates of zinc, lead, copper, iron, barium, and calcium.
large
shoots.
The
dissolved compounds were probably broken up by cold descending waters, which possibly also furnished the sulphur to combine with the metals.
In eastern Colorado fluorspar occurs in considColorado (2).

erable quantities in a belt extending from Boulder County to Custer
County. The veins, in most cases, cut granites and gneisses of
pre-Cambrian age that have been intruded by
later dikes, especially
Metalliferous minerals are associated with

of quartz porphyry.
the fluorite, but in several instances the latter forms most of the
vein
filling.
The
deposits have thus far not been extensively derather far from the rail-
veloped, and much of the material lies

road.
The three producing localities
County; Evergreen, Jefferson County;
are Jamestown, Boulder

v
and near Rosita, Custer
County.
In 1913 shipments were made from an interesting vein at Wagon
Wheel Gap (26). The fluorite here occupies a fissure averaging
3 feet in width in rhyolitic tuffs and breccias. It is associated
with hot springs, and contains small quantities also of barite,
in the altered
calcite, quartz, and altered pyrite, the latter mostly
wall rock.
Even small amounts
of gold
and
silver occur in the
fluorite.
New Mexico
found
(2o).
in steeply
Ten
miles north of Deming, fluorspar
is
dipping veins cutting monzonite porphyry, the
ECONOMIC GEOLOGY
330
and Cretaceous sediments, Fig.

2
to
5
feet in width, with a maximum
from
113. The veins range
a
show
of 12 feet and may
distinctly banded structure, or at other
times consist of massive spar with pockets of quartz. Brecciation
latter being intrusive in Paleozoic
4000
b,
andesitic
/,
monzonite;
map.
ft.
above Sea Level
Map and
FIG. 113.
sections of fluorspar deposits,
agglomerate;
g,
c,
basalt dikes;
(After Darton
sandstone;
h, rhyolite;
and Burchard, U.
d,
i,
Deming, N. Mex.
limestone;
e,
fluorite veins,
a,
Desert
fill;
intrusive granite;
marked
and 2 on
S. Geol. Sure., Bull. 470.)
The partly siliceous veins are slightly more

also common.
resistant than the surrounding porphyry, but at the surface the
fluorspar is in places altered to calcium carbonate.
is
Tennessee (3, 5) fluorspar comes from Smith,

Other States.Trousdale, and Wilson counties of that state; while that obtained
in Arizona (5) is mainly from the Castle Dome district, Yuma
County.
as
a
3
i
i
*
4
%
*
&
>
i
ECONOMIC GEOLOGY
332
Canada.
Fluorspar
and
County, Ont.,
is small.
is
also in
known
to occur near
Madoc, Hastings
Huntingdon township, but the output

Next to the United States, Great Britain
the largest producer, the fluorspar of Derbyshire and Durham, associated
with lead-zinc ores of the Carboniferous, serving as an important source
of supply.
Most of the mineral comes from the tailings of lead mines,
is
and the gob
Some
of abandoned workings.
idea of the importance of the industry
is gained from the fact that

the 1913 production amounted to 53,663 long tons, of which over 37 per cent
was shipped to the United States.
In
Germany
fluorspar veins are worked, especially in the southern Harz

The veins may be
Bavaria, Black Forest and Thuringian Forest.

large, and contain the common associates.
district,
Considerable gravel spar is produced as tailings

Imports.
from the English lead mines and shipped as ballast to the
United States, thus competing with the American product as
It is high in silica and is almost
far west as Pittsburg.
The estientirely consumed by open hearth steel makers.
mated imports for 1913 were not over 22,682 short tons, valued
at $71,463, while those for 1914 were 10,205 short tons valued
at $38,943.
These imports amount to about 22.3 per cent of the domestic

gravel spar production.
Cryolite.
This mineral, which
is
a sodium-aluminum fluoride,
not produced in the United States, the entire supply being

1
The
imported from Ivigtut on the south coast of Greenland.
is
quantity imported for consumption in the United States in 1914

tons, valued at $94,424, or an average price of
was 4612 long
Canada imported $33,487 worth in 1913.

The analyses (2, 3), given on page
Analyses of Fluorspar.
333, will indicate the variation in composition of the American
$20.47 per ton.
product.
Uses.
was
Fluorspar
hydrofluoric acid, but not
formerly used chiefly for making

more than 5 to 10 per cent of the
domestic product is now employed for this purpose, while increasing quantities are sold for the manufacture of opalescent glass.
The greatest demand for it, however, is as a flux in iron manufacture, since it saves from 3 to 5 per cent more iron than limestone flux, reduces the sulphur and phosphorus contents, and
1
Mining Magazine, Apr., 1916.
MINOR MINERALS
ANALYSES OF FLUORSPAR
LOCALITY
333
ECONOMIC GEOLOGY
334
FLUORSPAR MARKETED IN 1912-1914, IN SHORT TONS
STATE
MINOR MINERALS
335
coarser grades are employed for heavy castings.

The core sands
have but little cohesiveness, owing to their lack of
clayey matter,
and hence require the addition of an artificial binder.
Requisite Properties.
dry sands are:
The
requisite physical qualities of foun-
make the grains cohere

pressed together to form the parts of the mold, the deficiency
in this respect in core sands being supplied by artificial
binders;
2. sufficient refractoriness to prevent extensive fusion in the sand
when exposed to the heat of the molten metal; 3. texture adapted
1.
sufficient cohesiveness to
when
to the grade of casting to be poured in it; 4. sufficient

porosity
and permeability to permit the escape of the gases given off by the
cooling metal; 5. durability, or sufficient length of life, to permit
as
much of the sand
as possible being used over again.

of a molding sand might properly
include the determination of (1) its texture (by mechanical analy-
The laboratory examination
porosity, (3) permeability (by aspirator method), (4) average

1
fineness (by aspirator method), (5) tensile strength, and (6) refracsis), (2)
toriness.
Chemical analyses of foundry sands are in most cases of little

no light on the physical properties.
few are, however, given below
value, mainly because they shed
CHEMICAL ANALYSES OF FOUNDRY SANDS
ECONOMIC GEOLOGY
336
The
and
following table gives the mechanical analysis, specific gravity,

porosity of a number of samples of foundry sand.
PHYSICAL TESTS OF FOUNDRY SANDS
MINOR MINERALS
337

Many thousands of tons of
foundry sand are used annually by foundries, scattered all over
the United States. In most cases these represent natural mixtures,
but for some grades of work, especially steel casting, artificial mixtures of quartz, clay, etc., are used.
Sands for cores and molds for general
work are widely distributed

and obtainable from many surface formations, usually of recent age;
but the finer-grained sands, such as are required for stove plate and
The regions around Albany,
brass casting, are of rarer occurrence.
New
York, Conneaut, Ohio, Newport, Kentucky, Valparaiso, Indiana, etc., are noted for their supplies of the finer grades of molding sands. New Jersey is also an important producer, but there
is obtained largely from Cretaceous and Tertiary deposits.
In the digging of molding sand, careful sorting is sometimes necessary, the deposit of good sand being often thin, or of irregular
thickness, and interbedded with other sands of no value, although
the sand
closely resembling the good material.

The literature on molding sands is not extensive.
The value
is
of
molding sand produced
in the
United States in 1914
reported as $1,756,383, but these figures are probably only ap-
proximate.
REFERENCES ON FOUNDRY SANDS

1.
Newland, Amer. Foundrymen's Assoc., 1915. (Albany sand.) 2. Ktimmel

and Parmelee, N. J. Geol. Surv., Ann. Kept. 1904: 189, 1905. (General
and N. J.). 3. Merrill, Non-Metallic Minerals: New York, Wiley and
4. Ries and Gallup, Wis. Geol. and Nat. Hist. Surv.
Sons.
(General.)
5. Ries, Metal Industry
Bull. XV: 197,1906.
(Wis. and General.)
June and July, 1908. (Relative advantages of chemical and physica,
examination.) 6. Ries and Rosen, Mich. Geol. Surv., Ann. Rept. for
1907.
(General and Mich.). 7.. Watson, Min. Res. Va., Lynchburg,
1907:394.
(Va.).
8.
Condit, Jour. Geol.,
XX:
152, 1912.
(O.).
FULLER'S EARTH
may be regarded as a peculiar

absorbent
a
power for many substances,
type of clay which has high
for
is
of
value
it
on which account
decolorizing oil and other liquids.
Properties.
Fuller's earth (7)
and chemical composition are variable, and its specific

gravity ranges from 1.75 to 2.5. The quantitative analysis shows
it to differ chiefly from common clay in having a relatively higher
percentage of combined water.
Its color
The
following analyses represent the composition of fuller's earth
ECONOMIC GEOLOGY
338
from
of
different localities,
little
but
it
should be emphasized that they are
value in judging the quality of the earth
CHEMICAL ANALYSES OF FULLER'S EARTH
MINOR MINERALS
339
of low yield, are interesting because those of the most

important or Westerwald district are a weathering product of basalt, while some of the Saxon
ones come from the decay of gabbro and amphibolite.
Uses.
Fuller's earth was originally used for
fulling cloth,
but in this country its employment for this purpose is small, the
chief use being for bleaching, clarifying, or filtering,
fats, greases,
and oils. It has also been employed in the manufacture of pigments for printing wall papers, for the detection of certain coloring matters in some food products, and as a substitute for
talcum powder.
For treating mineral
cylinders,
and the
being that the
oil
oils
the carefully dried earth
is placed in
slowly through it, the result
comes out water white. In the treatment
allowed to
first oil
filter
of vegetable oils, these are heated in large tanks to above 212 F.,
from 5 to 10 per cent oil added, and after strong stirring, the mix-
ture put in a
filter
and the discolored
oil
strained out.
Production of Fuller's Earth.

Fuller's earth was dixcovered
in the United States in 1891 near Alexander, Ark.
It was subsequently accidentally discovered near Quincy, Fla., and this
state has remained the leading producer.
The domestic output
has never been large, and much is still imported from England.
PRODUCTION OF FULLER'S EARTH IN UNITED STATES, 1912-1914

YEAB
ECONOMIC GEOLOGY
340
REFERENCES ON FULLER'S EARTH

Amer. Inst. Min. Engrs., XLIII: 520, 1913. (Ark.) la.
Day, Jour. Frank. Inst., CL, 1900. (Distribution.) 16. Gilpin and
Branner,
1.
Bransky, U.
2.
earth.)
1901.
(General.)
Guide to Study
3.
of
(Diffusion of oil through

Non-metallic Minerals: 337,
Parsons, Bur. Mines, Bull. 71, 1913.
(Proper-
(Properties
Porter, U. S. Geol. Surv., Bull. 315: 268, 1807.
5. Ries, U. S. Geol. Surv., 17th Ann. Kept., Pt. Ill (ctd.):
tests.)
ties.)
and
Merrill,
4.
6. Ries, Amer. Inst. Min. Engrs., Trans. XXVII:

(General.)
7. Ries, Clays, Occurrence, Properties, and Uses, 2d ed.:
333, 1898.
la. Sellards, Fla. Geol. Surv., 1st Ann. Rept.
(General.)
516, 1908.
877.
and 2d Ann. Rept.: 257, 1909. (Fla.) 8. Vaughan, U. S.

9. Wesson,
Geol. Surv., Min. Res., 1901: 922, 1903.
(Ga. and Fla.)
Min. and Eng. World, XXXVII: 667, 1912. (Bleaching oils.)
33, 1908,
GLASS SAND
Glass sand
is
obtained from quartzose sands, sandstones, or

sand is employed, it is sometimes necessary to
When
quartzites.
it through a washing process in order to separate the impurities,

while in the case of sandstone or quartzite, at least a preliminary
put
crushing and screening are usually necessary.

Since silica is the major ingredient of
the sand, it influences the character of the ware to a marked degree.
1
Sand with impurities
is therefore to be avoided, especially if it is

to be used for the higher grades of glassware.
Chemical analysis of
almost any sand may show at least traces of iron oxide, alumina,
titanium oxide, lime, magnesia, and organic matter, but most of

these are included in mineral grains other than quartz.
Iron oxide, even in small amounts, colors the glass green, and is
avoided by a selection of the whitest sand, although whiteness does
not necessarily indicate freedom from impurities. Washing may
remove much of the iron, and the iron color may also be counteracted to some extent by the addition of arsenic. Magnesia causes
trouble by rendering the batch less fusible, but it is more apt to be
1
Frink (Ref 14) believes that

.
of
MgO
and
Al-iOs are incorrect,
monly imagined.
many of
the views held regarding allowable limit
and these substances are
less
harmful than
is
com-
MINOR MINERALS
introduced through the limestone than the sand.
able, since it tends to cloud the glass.
CHEMICAL ANALYSES OF GLASS SANDS
341
Clay
is
undesir-
ECONOMIC GEOLOGY
342
Few mechanical analyses of glass sands have been published,

but the following will serve to show the texture of several from different localities
(2, 3).
MECHANICAL ANALYSES OP GLASS SANDS

LOCALITY
MINOR MINERALS
343
and Crystal City on the Mississippi River.
Indiana (4) contains

sandstone suitable for glass manufacture in the Silurian,
Devonian,
Carboniferous, and Tertiary formations, but most of it comes
from the Mansfield sandstone of the Carboniferous in the southwestern part of the state. Beds of high-grade sandstone occur in-
terbedded with Silurian limestones in northwestern Ohio (4), but

the most important deposits are found in the Mississippian, Pottsville, and Lower Coal Measures in the eastern portion of the State.
In eastern Canada the Oriskany sandstone is used.
Production of Glass Sand.
About 19 states report a production of glass sand, but
glass manufacture.
all of
the material
The production
of the
as well as the total for the United States
is
may
not be used in
important producers
given below:
QUANTITY AND VALUE OF GLASS SAND IN UNITED STATES, 1912-1914
CHAPTER XI
MINOR MINERALS
GRAPHITE MONAZITE
GRAPHITE
Graphite, or black lead, as it is often
termed popularly, is a form of carbon, of which two varieties are
The first of these,

generally recognized, especially in the trade.
the crystalline, has a lamellar or flaky structure, and is of high
which is classe'd as amorphous, lacks
and may be quite impure. However, even
the purest graphite may contain at least a few tenths per cent ash
and volatile matter, and commercial graphite often contains an
Those containing 90-95 per
appreciable content of impurities.
cent graphitic carbon meet the requirements of the general trade,
purity, while the other form,
crystalline structure,
but for many purposes, especially paint-making, graphites with as

low as 30 to 35 per cent graphitic carbon can be employed.
The following analyses of graphite from a number of localities
(6) show the variation in its composition, but probably do not in all
cases represent commercial samples.
ANALYSES OF GRAPHITE
LOCALITIES
MINOR MINERALS
345
Graphite is usually easily recognized by its peculiar physical

properties, such as extreme softness, steel-gray to blue-black color,
greasy feel and black streak. The specific gravity is 2.20 to 2.27.
The luster is metallic in the leafy form, but earthy when the
graphite is in a finely divided state. In such event it may be
from amorphous carbon, although graphite can

be told by its property of forming graphitic acid, when treated
with nitric acid. Molybdenite is the only mineral with which it
might be confused, but this has a bluish or greenish tinge and a
difficult to tell it
greenish streak.
Mode of Occurrence.
Graphite always occurs in eruptive
or metamorphosed rocks, especially the latter. The different
occurrences include schist, gneiss, quartzite, crystalline limestones, granulite, syenite, etc.
The shape of the deposit is also varied.
may
in
form:
(1)
disseminations
metamorphic or
in
Thus the graphite
in
metamorphic rocks;
igneous rocks; (3) veins; and
(2)
pockets
(4)
bedded
deposits.
The gangue minerals

of separation,
are important, since they affect the process
in general those common to the c untry

case of veins, when they may be different.
and are
rock, except in the

Mica and chlorite are undesirable, as they are hard to separate.
Both quartz and calcite may be common gangue minerals, and

the less abundant may include rutile, titanite, apatite, etc.
It seems probable that graphite may
Genetic Occurrence.
be of either igneous or sedimentary origin, although the latter is
more important. The following cases are recognized:

There is no doubt that graphite may
In Igneous Rocks.
form an original constituent of rocks formed by the cooling and
possibly the
1.
For examples of this we may refer

crystallization of a magma.
of
to the occurrence
graphite in meteorites, in the native iron of
in
the
nepheline syenite of Siberia, or in pegmatite
Greenland,
dikes.
Of course, where the intrusive rock has pierced sedimentary

ones, there is always the doubt or possibility that the graphite
may have been derived from these. This fact thas been pointed
1
out in the case of a graphite-bearing pegmatite from Maine,
and another from New Jersey.2

This manner
2. In Veins.
1
Smith, U.
S.
G.
of graphite occurrence affords
S.,
Spencer, U. S. G.
Bulk 285: 280, 1906.
S.,
Geol. Atl. Fol. 161, 1908.
346
ECONOMIC GEOLOGY
puzzling problem.
The
and may be several
veins appear to represent fissure filling,

They are found not only in
feet in width.
igneous rocks such as granites and pegmatites, but also in metamorphosed sediments, and while they were probably formed at
considerable depths, it has been suggested that in some cases at
1
least, the temperature did not exceed 575 C.
Some
believe that the graphite
was derived from surrounding
sediments, and deposited shortly
after the pegmatitic injection.
Others hold the view that the graphite has been derived from
gaseous constituents of the magma, it being pointed out that if
CO and are present, they will react below 500 C. according to
the equation
2CO+2H 2 <^2C+2H 2 O.
This
may
be the origin of the graphite in the veins of Ceylon,
Montana and New York.

These may include regionally and
3. In Metamorphic Rocks.
and contact metamorphosed rocks. It is quite generally admitted
that the carbonaceous matter of sedimentary rocks may undergo
a recrystallization during metamorphism resulting in the formation of graphite.
Where graphite has been produced by contact metamorphism,

some writers (Weinschenk) have sought to show that it represents
exhalations from the magma, but this hardly seems necessary,
when we find that the metamorphosed formation,

away from the eruptive, is carbonaceous.
especially
traced
if
The intrusion of igneous rocks into or near coal appears in

some cases to have produced crystalline (l, p. 41), in other instances
2
As an example of the latter we may
amorphous graphite.
refer to deposits in central Sonora, Mexico, where coal beds up
to 24 feet in thickness, enclosed in sandstone, have been meta-
morphosed by
Distribution
granite.
of Graphite in the United States.
Crystalline
graphite is widely distributed in the United States, occurring in
contact zones between igneous and sedimentary rocks, in metamorphic rocks, etc., but the known deposits of commercial value
are few in number.
Most
of the domestic supply has
been obtained from
New York
State.
New
1
York
(4, 11, llo, 12).
Bastin, Econ. Geol. V: 152, 1910.
The producing mines

2
are located
on
Bastin, U. S. Geol. Surv., Min. Res. 1908.
MINOR MINERALS
FIG.
114.
Map
showing
principal
graphite
mines
347
of
northeastern
states.
Crown Point Graphite Co.; 2. Ticonderoga mine; 3. Dixon's American

Mine; 4. Hague mine; 5. Rowland Graphite Co.; 6. Champlain, and Adiron1.
dack Graphite Companies; 7. Sacandaga Graphite Co.; 8. Empire Graphite

9. Saratoga Graphite Co.; 10. Macomb Graphite Co.; 11. Bloomingdale
Mine; 12. Raritan Graphite Mine, High Bridge; 13. Eynon Graphite Co.,
Coventry ville; 14. Girard Graphite Co., Rock Graphite Mining Co., Crucible
Flake Graphite Co.; 15. Anselma Mine, Federal Carbon Mine, Chester Mine;
17. Boyertown Mine;
16. Acme, Pennsylvania and Pettinos Bros.' Mine;
20. Sturbiidge Mine.
18. Penn Mine, Mertztown;
19. Baokenstoe Mine;
(U. S. Geol. Sure., Min. Res. 1913.)
Co.;
ECONOMIC GEOLOGY
348
the southeastern side of the Adirondacks in Essex, Warren, Washand Saratoga counties, and the state leads all others in its
ington,
production of graphite, partly because of the steady production of

one large mine.
The graphite occurs in the following ways 1. In pegmatite veins,
forming bunches, associated chiefly with quartz, but also feldspar,
:
pyroxene, hornblende, mica, calcite, scapolite, apatite, sphene, etc.

This type of deposit is of little commercial value. 2. Veinlets of
graphite with quartz in gneiss.
ing
3.
Graphitic quartzites, representThese are the most
metamorphosed pre-Cambrian sediments.
Graphitic disseminations in Algonkian lime-
4.
important type.
stones.
At the American Graphite Company's mine, which is represenworked is a medium-grained, quartz-
tative of 3, the material
graphite schist, which averages 6.25 per cent graphitic carbon.

The associated minerals are quartz, mica, and apatite. The graphite rock varies from 3-20 feet in thickness, and is overlain by
garnet gneiss.
Rhode Island
Amorphous graphite, graphitic anthracite, or

as
it
has
been variously called, has been known for
graphitic shale,
to
in
occur
the metamorphosed Carboniferous rocks
many years
(5).
near Providence and Tiverton, Rhode Island, but the production

has been irregular. At the Cranston Mines near Providence, which
are the largest, the section shows a series of interbedded, sandy,
carbonaceous, and graphitic shales, something over 300 feet thick,

all folded and perhaps faulted.
The main graphitic bed is 30 feet
thick.
The following analyses represent the range of composition

the material:
01
13.26
23.68
1.
2.
2.56
3.01
65.30
42.54
18.88
30.77
Ashley has characterized the material as a high-ash, highgraphitic anthracite coal of high specific gravity
(1.65-2.45), which cannot be used successfully as a fuel, unless it
can be mined and delivered at the furnace in Providence or Boston
for less than one-half the wholesale price of competing coals.
moisture,
The material
Pennsylvania
ties in eastern
is
(8).
used chiefly for paint and foundry facings.

Crystalline orraphite has been mined at several localit occurs in crystalline rocks.
Pennsylvania, where
MINOR MINERALS
349
Alabama (14).
Crystalline graphite is found in granites and schists in
Clay, Chilton, and Coosa counties. In Clay County, for example, the graphite is uniformly disseminated throughout a zone of mica-free weathered
Its depth has been
granite, ten miles long and several hundred feet wide.
proven to 75 feet, with an average of 4.5 per cent graphite. A graphitic
clay found in the slightly crystalline schists of the Palaeozoic area of Clay
and Tallapoosa counties is used as a lubricant.
New Mexico (10).

of the
Amorphous graphite
is
known
to occur in the
Canadian River, about 7 miles southwest of Raton.
The
canon
bed, which
nearly horizontal, has been traced laterally into the principal bituminous
seam of the Raton field, and that portion which is graphitized owes its
character to diabase intrusions, the change being most complete where the
bed was fractured and the diabase forced into it. The graphite is said to
occur in pockets or irregular masses in the diabase, and is columnar normal
It has been mined somewhat and sold for
to the faces of the igneous rock.
is
coal
the manufacture of mineral paint.
Montana (20).
Near Dillon, Mont., there is a deposit somewhat similar
to those of Ceylon, for the graphite occurs in veins.
These may be irregular,
forming a network, or some of the narrow ones appear persistent. They
occur in schists and crystalline limestones, which have been penetrated
The graphite is said to be softer than the Ceylon product.
Other States.
Developments of graphite have been made in other
by pegmatite.
states,
such as Michigan, Wisconsin, Virginia (17),

(9), etc., but the output is not steady.
Wyoming
(2),
Maine
Georgia
(15),
Canada (l, 6).

Mining for graphite in Canada began in
and
continued
has
since, the production coming from rocks
1847,
of the Hastings-Grenville series of eastern Ontario and the
adjoining portions of Quebec. The 1913 production came from
the
district, Quebec and Calabogie and Wilberforce,

Canadian graphite occurs in the following three ways:
Buckingham
Ont.
the beds
(1) As disseminations in gneiss, quartzite or schist,
being sometimes more highly graphitic, where pierced by intruin or near igneous
sives; (2) As usually narrow or irregular veins,
near igneous
rocks; (3) As veins or irregular masses in limestone
veins
cutting the
As a constituent of pegmatite
rocks;
(4)
Grenville series.
Only the
first
of these
is
of
much economic
importance.

Ceylon (1, 3) is the leading graphite-prothe mountainous
ducing country of the world, the chief mines being locatedjn
chief
area of the southwestern and south central part of the island. The
some
and
intrusives,
interbedded
dolomites,
rocks are gneisses with some
While some disseminated graphite is found
especially granite pegmatites.
in gneiss
and limestone, the commercially important deposits are veins
irregular width, occurring along fracture planes.
of
In small veins the graphite
ECONOMIC GEOLOGY
350
forms an aggregate of parallel needles at right angles to the wall, but in

the larger veins a coarse platy structure is observed.
Pyrite and quartz
are not uncommon, while biotite, orthoclase, pyroxene, apatite, allanite,
and
rutile are
more
rare.
another important producer. There, in the Passau district

(Fig. 115), the country rock is cordierite gneiss, surrounded by granite, and
containing bands of schist, and limestone, as also some intrusive rocks.
Bavaria
FIG. 115.
(1) is
Geologic
map
of Passau, Bavaria, graphite district.
De Launay, from
Stutzer,
(After Giimbel-
Die Nicht-Erze.)
The
graphite forms lenses conformable with the gneiss and schist, with often
a foot wall of limestone and syenite, and a hanging wall of granite. Both
the country gneiss and graphite are strongly decomposed. Weinschenk
advanced the theory that the graphite was deposited by exhalations from
the granite, and that the kaolinization was due to the same cause. The
first is disputed by some, who consider the carbon to be original in the
rock, while the latter
of weathering.
is
very unlikely, the kaolin being an ordinary product
Austria is the largest producer in Europe, the deposits of southern Bohemia being similar to those of Bavaria. The Styrian ones form thin beds
MINOR MINERALS
351
and those of Mahren occur in crystalline limestone which is interbedded with schists, gneisses and quartzites. The Madagascar l deposits
of crystalline graphite, and Ko:ea 2 deposits of amorphous graphite are
in schist,
also important.
Uses.
On
account of
its refractoriness
and high heat con-
ductivity, graphite is employed in the manufacture of crucibles

for use in the steel, brass, and bronze industries.
For making
these
it is
mixed with clay and some sand.
Ceylon graphite
is
specially suitable for this class of work, because of its peculiar

fibrous structure, but small amounts of American and Madagascar
graphite are also used.

success in crucible work.
making stove
Amorphous graphite has not

In addition graphite
is
given
employed
for
foundry facings, paint, lead pencils, lubricating powder, glazing, electrotyping, steam piping, for adulterating
fertilizers, coloring and
glazing coffee beans or tea leaves,
polish,
etc.
The use of graphite for paint has increased greatly in the last
few years, the material employed being chiefly of the amorphous
variety and rather impure. Another recent and increasing use
of amorphous graphite and of fine flake graphite is for boiler compound.
Both amorphous and crystalline graphite can be used for lubriThe use of graphite for pencil manufacture,
cating purposes.
and perhaps the best known, consumes but
an
one,
early
though
a small percentage (under 10 probably) of the world's supply.
this purpose amorphous graphite is demanded, and while
Bohemian and Bavarian graphite were originally used, Sonora,
Mexico, now supplies American manufacturers with all they
For
need.
Graphite
is
also
made
artificially
from anthracite
coal,
but
its
introduction has not seriously affected the market for the natural
product.
Crystalline graphite is put through a concentrating process beshipment to market. This is necessary in order to free it from
fore
Both wet and dry methods of separation

more recently air separation has been tried
the associated minerals.

are employed, while
with some success.

In spite of the importance of graphite,
Graphite Industry.
not
the United States does
produce more than about one-seventh
1
U. S. Geol. Surv., Min. Res., 1913: 23, 1914.
Ibid., p. 238.
352
ECONOMIC GEOLOGY
of the total quantity consumed in this country.

condition of the domestic industry is due to:
This unsatisfactory
(1)
The
superiority
low cost of production of the

(2)
Ceylon product; and (3) the fact that both United States and
Canadian graphites are disseminated and hence require separation
of the Ceylon product;
the
from the associated minerals. Considerable Madagascar graphite, which is of the flake variety, is imported into the United
It is cleaned after being received here.
States.
Korean amoris also imported.
Production of Graphite.
The domestic production of crystalline graphite does not form more than a small proportion of the
phous graphite
entire consumption.
In 1914 the total production of crystalline graphite came from
New York, Pennsylvania, and Montana. The Alabama

production amounted to 2,410,200 pounds, valued at $118,000,
which was less than half of the total production of 5,220,539
Alabama,
pounds, valued at $285,368. Alabama showed a slight increase

over the production of the previous years.
PRODUCTION OF NATURAL GRAPHITE IN THE UNITED STATES, 1910-1914
MINOR MINERALS
WORLD'S PRODUCTION OF NATURAL GRAPHITE IN 1912
COUNTRY
353
ECONOMIC GEOLOGY
354
LITHIUM
The two minerals most commonly used
(KLi[Al(OH,F )]Al(SiO3) 3 )
Lepidolite
The
as a source of lithium are
and Spodumene (LiO 2 A1 2O 3

,
known in the
United States are found near Pala, California. Spodumene occurs
in some quantities in the Black Hills of South Dakota and in Con4 Si0 2 ).
largest deposits of lepidolite at present
necticut and Massachusetts, but none of these occurrences have

yet been worked to supply lithium.
In the last few years there has been a great demand for lithium
minerals for use in the manufacture of lithium carbonate. Since
most of this substance now in use is made in Germany, nearly all the
American mineral has been shipped to that country. The American
supply of carbonate is imported from Germany, selling in New York
for $4.20 a
pound. The chief use of lithium
salts is in the
preparation
of mineral waters.
The production of lithium minerals in the United States

very irregular and small.
is
LITHOGRAPHIC STONE
Lithographic stone
Properties.
homogeneous limestone, used
(1,
3)
is
a very fine-grained,
It
for lithographic purposes.
may
be either pure lime carbonate or magnesian limestone, but so far as

known this difference in composition exerts no important influence
The two following analyses will serve to

its physical character.
indicate this difference in composition, No. 1 being the standard
Bavarian stone and No. 2 the Brandenburg, Kentucky, rock:
on
SOLUBLE IN HCI
INSOLUBLE IN HC1
SiO 2 (AlFe) 2 O 3
CaO
A1 2 O 3
FeO
MgO
1.
1.15
.22
Trace
.23
.26
.56
2.
3.15
.45
.09
.13
.31
6.75
CaO
Na 2 O K,O
Moist.
HO
CO 2
53.80
44.76
.07
.23
.69
.13
.41
.47
42.69
43.06
The physical character of the stone is of prime importance, for in

order to yield the best results it should be fine-grained, homogenefrom veins or cracks, of just sufficient porosity to absorb the
grease holding the ink, and soft enough to permit its being carved
with the engraver's tool. Owing to these strict requirements but
few localities have produced good stone.
ous, free
MINOR MINERALS
355
Sources of Supply.
Lithographic stone is not confined to any
one geologic formation, and deposits have been reported from many
states both east and west.
Some of these appear to be of inferior
while
others
are
too
far from railroads.
The most promquality,
is
that
found
at
ising developed deposit
Brandenburg, Kentucky
(2, 6), at which locality a bed of blue-gray stone three feet thick is
quarried and used by some establishments in the south and southwest. Another bed of good quality has also been described from
Iowa
(1).
The main source of the world's supply is obtained from the Jurassic
limestone of the Solenhofen district in Bavaria (4), in which the quarries
have been worked for a number of years, but the supply is said to be
The stones are trimmed at the
becoming unsatisfactory and unreliable.
quarries, and sizes of 22 or 28 by 40 inches are in the greatest demand.
From
sell
these they range
up
to sizes
The
40 by 60 inches.
best quality stones
for 22 cents per pound.
The domestic demand is not large, and it is probable that one or

two well-developed and well-managed native quarries could no
doubt satisfy it.
The successful substitution of zinc or aluminum plates for certain
classes of lithographic work is said to have had a noticeable influence on the demand for lithographic stone.
Onyx has also, in
some cases, been found to make a good substitute.
REFERENCES ON LITHOGRAPHIC STONES
1.
XIII 339, 1902. (la.,

Hoen,
Eng. and Min. Jour., LXXII 668, 1901.
la. Geol. Surv.,
Resources, U.
article.)
1913.
4.
S.
(Europe.)
6. Ulrich,
Geol. Surv., 1900
Dammer und
5.
Mo.
Tietze,
Geol.
also general.)
2.
Kiibel,
(Ky.) 3. Ktibel, Min.

869, 1901.
(Excellent general
Nutzbaren
Surv.,
Eng. and Min. Jour., LXXIII:
412,
Mineralien, I:
1890.
38,
(Mo.)
895, 1902.
(Ky.)
Bull.
3:
MAGNESITE
This mineral, which is a carProperties and Occurrence.
bonate of magnesium with 47.6 per cent magnesia (MgO), has a
hardness of 3.5 to 4.5 and a specific gravity of 3 to 3.12.
It commonly occurs in veins or in masses replacing other rocks
'rich in
etc.
magnesia, such as serpentines, talcose
schists, dolomites,
and when massive it someand is quite brittle, but when
Its color is white or yellowish,
times resembles unglazed porcelain,

limestone.
crystalline it resembles coarse-grained metamorphosed
ECONOMIC GEOLOGY
356
Magnesite occurrences may be grouped into two classes,

the dolomite and the serpentine type.
The only important occurrence of
Dolomite Type (4).
viz.:
this
type is in a belt in Austro-Hungary, the mcst important district

being near Veitsch in Styria. The material, which is coarsely
crystalline, occurs as replacements of Carboniferous dolomite,
and may not only contain an admixture of siderite, or even scattered metallic sulphides, but also veinlets of dolomite and sometimes
talc.
These deposits form the main source of the world's
supply.
An impure
magnesi+e containing considerable dolomite is

Quebec, and a deposit of hydromagnesite at Atlin, B.C.
This type forms veins (PI. XXXV,
Serpentine Type (i, 3, 4).
known
in
and has been derived from the

even from the minerals that altered to serpen-
Fig. 2), or lenses in serpentine,

latter, or possibly
tine,
probably by the action cf surface waters.
The
following
equations will illustrate this change:
H 4 Mg3 Si20 9 + 3C0 2 = 3MgC0 3 +2Si0 2 +2H 2

or
3Mg3FeSi 2 08+3C02+4H 2 0+O
The
silica formed above may be deposited with the magnesite,

or in separate veins as opal or chalcedony.
Other impurities in the magnesite may be iron, alumina and
lime.
In texture the
serpentine magnesite
is fine
grained, dense or
massive, and when pure, white in color.

Although this type is of almost world- wide distribution, the
most important deposits are on the Island of Eubosa, Greece,
where some of the lenses are 50 feet thick and 75 to 100 feet
long
(4).
Small ones are known in Pennsylvania and Maryland, but are

not worked, as they cannot compete with the imported magnesite.
(l).
Deposits of magnesite (Fig. 116) are scattered
the
Coast
Range from Mendocino County at least to a point
along
south of Los Angeles, and along the western slope of the Sierra
Nevada from Placer County to Kern County. The greatest pro-
California
duction comes from near Porterville in Tulare County (Fig. 116).
PLATE
FIG.
FIG. 2.
1.
XXXV
Magnesite mine near Winchester,
Network
Calif.
of magnesite veins in Serpentine,
(//. Ries, photo.)
same mine. (H.
Ries, photo.)
(357)
ECONOMIC GEOLOGY
358
The
deposits all occur as veins in serpentine, the larger

being in the Coast Range.
FIG. 116.
Map
of part of California
(After Yale
and
number
showing distribution of magnesite deposits.

Min. Res. 1913.)
Gale, U. S. Geol. Sun.,
The much-fractured and
faulted serpentines of the Coast

which
are
Ranges,
probably of Lower Cretaceous age, appear
to have been derived from olivine-pyroxene rocks, and the magnesite may have been formed from both the serpentine-making
MINOR MINERALS
359
minerals and the serpentine itself. In some cases the

magnesite
forms a network of veins in the serpentine, but since its
origin
is due to the action of surface
waters, the
be of
deposits
FIG. 117.
may
Plan of magnesite veins and workings 4 miles northeast of Porter(After Hess, U. S. Geol. Surv.
ville, Calif.
Bull. 355.)
limited depth.
As the magnesite weathers less readily than the
serpentine, the vein outcrops often stand out in bold relief.
The following analyses show the composition of the magnesite
from several
localities:
ANALYSES OF MAGNESITE
ECONOMIC GEOLOGY
360
Crude magnesite is used chiefly for making carbon

but
its application for this purpose is decraasirg.
dioxide,
Caustic magnesite is that which has not been thoroughly
calcined and contains 3 to 4 per cent carbon dioxide.
This is
Uses.
used for making oxychloride cement (a mixture of magnesia and

magnesium chloride), and probably over 90 per cent of the serpentine magnesite
is
employed
for this purpose.
The
caustic
magnesite deteriorates on exposure, and after 4 or 5 months may

have taken up two or three Hmes as much carbon dioxide as was
left in it.
Dead-burned magnesite has less than

and does not take up any from the air.
per cent carbon dioxide,

The dolomite variety is
used almost exclusively for this purpose and goes into the manufacture of refractory bricks.
Magnesite is used as a toilet preparation, or in medicine,
as a boiler covering when mixed with asbestos.
and
California magnesite has been used in the paper-manufacturing

Epsom salt, while
industry, after conversion into bisulphite.
derived chiefly from the Stassfurt salt deposits,
is
also
manufac-
tured from magnesite.
The metal magnesium is not made from magnesite, but from

magnesium chloride obtained from the Stassfurt, Germany, and
other brines.
The domestic production

and has been as
is
obtained entirely from California
follows:-
PRODUCTION OF MAGNESITE IN UNITED STATES, 1912-1914

YEAR
PLATE
jr lt
vi ew
gl ass S and pit,
tion of bed of glass sand.
XXXVI
on Severn River, Md.
The
The tunnel shows
overlying beds carry too
much
posiiron oxide.
(H. Ries, photo.)
FIG. 2.
-View showing sapphire workings, Yogo Gulch, Mont. (Photo by

dike.
Rowe.) The cut indicates position of sapphire-bearing
(361)
J. P.
362
ECONOMIC GEOLOGY
OF MAGNESITE INTO THE UNITED STATES
FOR CALENDAR YEARS 1912-1914, IN POUNDS
IMPORTS, FOR CONSUMPTION,
MINOR MINERALS
363
been located in Grant County, New

Mexico, and although not
yet commercially developed, deserve mention.
Sepiolite has a probable composition of
H4 Mg2Si 3 Oio, and when
pure is a white, porous mineral, with a specific gravity of about 2.

It absorbs water readily,
becoming somewhat plastic, but hardens
again on drying. It has a hardness of 2 to 2.5, great toughness, and
earthy or conchoidal fracture, the toughness being most pronounced
having a leathery or fibrous texture. Its peculiar
physical properties make it of great value for carving into pipes.
In New Mexico two localities are
both of which lie in the
in those forms
known,
upper Gila River valley, at points located respectively 23 miles
east of north, and 12 miles northwest of Silver
City.
At the Dorsey mine, northwest of Silver City, the meerschaum
occurs as veins, lenses, seams, and balls in a limestone of
probable
Ordovician age. The veins are filled with chert, quartz, calcite,
clay, and meerschaum, and the chert which is the most important
gangue mineral, occurs in the veins with meerschaum in bands,
lenses, and nodules.
The meerschaum
massive form.
less leathery,
itself
occurs either as irregular nodules, or in
Both kinds are tough, but the

and heavier.
latter is finer grained,
The three following analyses represent, (1) the Dorsey mine

product; (2) the theoretic composition of meerschaum; and (3) a
material from another deposit, which resembles the true meerschaum, but
differs
from
it
in its high
alumina content.
ANALYSES OF MEERSCHAUM
ECONOMIC GEOLOGY
364
REFERENCES ON MEERSCHAUM
1.
Min.
XXVI:
(N. Mex.) 2. Sterrett, U. S.

688, 1907.
1908.
(General and N. Mex.) 3. Dammer
Tietze, Nutzbaren Mineralien, II: 354, 1914.
Collins,
\Vld.,
Geol Surv., Bull. 340:
and
MICA
There are few minerals more
in
distributed
rocks
than mica, and yet deposits
widely
crystalline
economic value are rare because the mica flakes are either too
small, or too intimately mixed with other minerals for profitable
extraction.
Only two of the several known varieties of mica,
muscovite (H2KAl 3 Si 3 Oi2) and phlogopite (HgKeMgyA^SiO^T),
are of economic value, the former only being found in deposits
of commercial value, in the United States.
Both phlogopite and
muscovite are found in Canada, but only the former is of much
commercial importance. The India mica, which is shipped to
the United States is muscovite.
The commercial deposits of muscovite are found in pegmatites,
cutting granites, gneisses, and schists. In these the mica is associated with quartz and feldspar (usually orthoclase or microcline, more rarely plagioclase) being found in rough crystals called
blocks or books, and which are either irregularly distributed
through the vein or collected near its sides.
of
In addition to the quartz and feldspar, other minerals such as

tourmaline, beryl, zircon, columbite, samarskite, uranium min-
sometimes present. The pegmatite, which

and may be of igneous or gas-aqueous origin,
erals, garnet, etc., are
carries the mica,
occurs as lenses, veins, irregular masses, etc., of varying thickness

and length. The value of the deposit depends more on the
abundance and quality
of the
mica than the
size of
pegmatite
body.
The best mica is obtained from the more coarsely crystalline

rocks; but the widest veins do not necessarily contain the largest
blocks. As a rule the mica does not form more than 10 per cent
of the vein, and usually not more than 10 or 15 per cent of that
mined can be cut into plates, the rest being classed as scrap mica.
There has been some discussion as to whether the pegmatites
are true igneous dikes or veins, but the matter cannot be said to
be definitely settled in all cases. It is probably that each type
of origin
is
represented.
MINOR MINERALS
The phlogopite mica
of
Canada
365
found in veins or dikes of
is
pyroxene cutting gneiss or limestone. Its chief associate is

apatite, occurring in a granular form or large rough crystals.
Other minerals present in smaller amounts are calcite, scapolite,
The deposits are

titanite, and even sulphides.
to the apatite scapolite veins of Norway.
similar
In
genetically
these the phlogopite occurs in the same irregular manner as the
muscovite In pegmatites.
tourmaline,
The value
of a
mica deposit depends on the abundance and
of the books, perfection of cleavage, color and clearness.

Large sheets of mica are the exception rather than the rule.
size
Mica may show
several internal structures which affect its

These are:
"
A " structures, which are striations or slight ridges
(1)
appearing on cleavage faces, and following definite crystallo"
V." (2) Herring-bone strucgraphic lines, meeting to form a
ture, similar to the preceding, but with a third set of striations
"
A." (3) Ruled mica, resultbisecting the obtuse angle of the
ing from the development of partings, and forming a series of
straight, sharp, parallel cracks which cut through the book, at
an acute angle to the cleavage face.
Large mica crystals may include smaller ones, or also grains
or crystals of other minerals. Mica containing minute inclusions
These inclusions may be dendritic in
is known as specked mica.
market value.
character.

Deposits of mica have
been worked in a number of states both east and west, and yet
but few are steady producers. The more important ones may be
described.
The mica mined in this state, which is

from three belts (Fig. 118); viz., the
comes
the leading producer,
Blue Ridge, and the Piedmont belts.
the
Cowee-Black Mountain,
"
That from the first is chiefly clear and of light color (" wine
or "rum "); that from the second is dark smoky brown and often
more or less speckled, while that from the third is often of good
quality and similar to the Cowee-Black Mountain product. OwNorth Carolina
(4, 9).
ing to a frequent capping of residual
soil,
discovery of the deposits
is difficult.
The mica-bearing pegmatites occur

hornblende, and granite gneisses and
in mica, garnet, cyanite,
schists, all of
the important formations being the Carolina and
Archaean age,
Roan
gneisses.
ECONOMIC GEOLOGY
366
The rocks of these two are interbanded with, and cut by, streaks of
granitic or pegmatitic material, the latter forming lenticular bodies
100
50
Chiefly clear
rum- Areas
colored-mica
FIG. 118.
Map
showing
areas in
150
of principal
200
-Mile,
Chiefly dark-colored
or specked mica
productiou
North Carolina
in
which mica has been mined.
(After Sterrett, U. S. Geol. <Sur., Bull. 315.)
or vein-like deposits, which may, or

the schistosity of the country rock.
>11
MicaeneiM
rock and horwt
FIG. 119.
Pegmatite
Mica pocket.
Mica pockets
may
not be conformable with
Quartz
Solid granular
mica in quartt
Section across pegmatite at Thorn Mountain mine,

(After Sterrett, U. S. Geol. Surv., Bull. 315.)
Macon
Co., N. Ca.
While they vary in size, 1 to 2 feet seems to be the minimum

"
workable limit for rich and regular
veins." The muscovite,
which is the main mica present (biotite being the other), shows a
At one time it is evenly distributed
variable mode of occurrence.
MINOR MINERALS
367
through the pegmatite, at another large crystals are found in

clusters scattered through the vein
(Fig. 119).
The better grades of North Carolina mica are used for the glazing
industry, while the less perfect sheet material is employed for electrical work.
The pegmatite veins also carry a number of rare minerals.
South Dakota (s). Mica is mined in the region around Custer,

South Dakota. The muscovite, as is usual, occurs in pegmatite,
cutting schists and gneisses, and granite. The material is of
evenly granular texture, or shows an irregular segregation of the
minerals, with but little banding. This latter is sometimes
800
FIG. 120.
ft.
Generalized cross section of No. 1 or New York Mine, near Custer

(After Sterrett, U. S. Geol. Surv., Bull. 380.)
South Dakota.
roughly produced by a segregation of the mica along the walls of

the deposit. Very few of the pegmatites around Custer, however,
carry enough mica to pay for working them.
In the New York mine (Fig. 120), for example, the rough mica
obtained along the walls amounts to 6 or 7 per cent, while the
interior portion of the pegmatite carries about 0.5 per cent, and
not worked. The shape of the pegmatite bodies around Custer
is
variable, but in general they resemble the dike type, and appear
to represent an end phase of the granite intrusions of that region,
for they not only cut the granite itself, but in places grade into it.
is
Their age
is
not definitely known.
Mica in pegmatite has been worked at Mica Hill, 4 miles

Other States.
northwest of Canon City, Colorado, and 6 miles north of Texas Creek. That
obtained at the former locality is peculiarly adapted to grinding purposes (10).
occurrences, especially those in Amelia and Henry
some importance. That found near Amelia Court House
and at Eidgway, Henry County, occurs in pegmatite dikes, which inter-
The
Virginia
(12)
counties, are of
ECONOMIC GEOLOGY
368
The largest dikes are more than

50 feet wide, and the mica occurs in them as thick, highly cleavable blocks,
and masses of varying size. Deposits are also known to occur in northwest
Georgia (4), and while they resemble the North Carolina deposits, they have
not been worked much.
sect the biotite gneiss of the district.
Distribution in
Canada
(2).
Muscovite deposits are found
over the Dominion, where the prequite widely

Cambrian crystalline rocks are exposed. They have been worked
at a number of localities, but are of little commercial importance
distributed
at the present time.
Fhlogopite deposits are confined to two areas, viz.: (1) The

Quebec area lying between the Gatineau and Lievre rivers;
and (2) the Ontario area lying principally east of the Kingston
and Pembroke Railway.
The most important mine in Canada, is that worked at Sydenham, Ont. (PL XXXII, Fig. 2), which has attained a depth of
nearly 200 feet. The only other important active one is in Templeton township northeast of Ottawa.
"
"
lead
varies from a few
In the Sydenham mine the mica
inches to 25 feet in width, being at times almost a solid mass of
The mica is mottled, wine-amber, and

crystals.
occurs in a greenish-gray pyroxenite. Bunches of massive apatite are occasionally met, and these are mixed with white calcite.
enormous mica
The leading world's producer is Bengal, where

muscovite mica has been obtained for many years. It is found associated
with quartz, feldspar, and kaolin, in pegmatite veins cutting gneisses and
Much muscovite has also been obtained from the pegmatite veins
schists.
of
German East
Africa
(3).
The irregularity of its occurrence

Mining and Uses (2).
makes mica mining somewhat uncertain. This often leads to the
type of mining known as ground hogging or gophering. The
rough crystals obtained from the mine range in size from small
These rough crystals are
crystals to blocks several feet across.
cobbed and cleaned, and then split into plates about one sixteenth
inch thick.
The
plates then have the rough edges cut off, and

and quality are ready for further splitting
Mica can be split into sheets one five-hundredth
after grading as to size
and trimming.
of an inch or even
The
less in thickness.
mica is for electrical purposes, it being

as an insulating material in dynamos, motors, high-
chief use of sheet
employed
voltage induction apparatus, switchboards, lamp sockets, etc.
MINOR MINERALS
369
The domestic product
is found to be
uniformly satisfactory for
work, except for insulation between the copper bars of
commutator segments. This use seems to be best served by the
electrical
amber or phlogopite mica
of
Canada and that
The
of Ceylon.
superiority of this variety is due to its easier wearing qualities,

which cause it to wear down even with the copper segments. Mi-
mica board is sheet mica obtained by cementing small

mica together under pressure. Since it can be
and
bent, rolled,
punched, it is utilized mostly for the same puras
sheet
mica.
The use of mica for stove doors and chimneys
poses
canite or
clear pieces of scrap
is decreasing, although the glazing industry still demands a considerable amount of the finest grades of sheet mica.
Scrap mica
is
ground for use
in the
manufacture of wall papers, lubricants,
fancy paints, and micanite. That used for electrical work must
be free from metallic minerals, and that for wall paper and paints
must have sufficient luster.

Ground mica is also used in rubber goods as an adulterant,
while mixed with shellac or plaster it is employed in the form of
moulded mica for insulation of trolley wire. Tar and other roofing
papers
may
be coated with coarse flakes of bran mica to prevent
Micarta is a mica product

sticking when rolled for shipment.
used as a substitute for hard fiber, glass, porcelain, hard rubber,
etc., for use in commutators and other parts of electrical apparatus.
The quantity and value of mica proProduction of Mica.

in the United States from 1910 to 1914 by kinds is given
below. The complete production by states is not given by the
duced
United States Geological Survey.

PRODUCTION OF MICA IN THE UNITED STATES FROM 1910 TO 1914
ECONOMIC GEOLOGY
370
The average prices for the individual states vary

from
greatly
year to year, due in part to variation between proporThe
tion of rough and trimmed mica, and size of sheets produced.
2d
North
of
of
several
sizes
1st
and
grade
prices per pound
Carolina mica in 1913 were as follows:
cents in 1912.
2X2
$1.35;
in.,
4X6
2X3 in., $.70; 3X3 in., $1.15; 3X4

$2.25; 6X8 in., $4.00; 8X10 in., $6.00.
$0.30;
in.,
The imports
of
in.,
mica are given for the last five years, since to

would not clearly show the fluctuations.
state those of one year
MICA IMPORTED AND ENTERED FOR CONSUMPTION IN THE UNITED STATES,

1910-1914, IN POUNDS
MINOR MINERALS
371
used directly after cleaning and grinding, while others are roasted to
give the desired color.
The substances used and considered in this chapter include
ocher, umber, sienna, hematite, siderite, ground slate, and shale.
Other substances used in the paint trade, but mentioned elsewhere,
are asbestos (p. 298), asphalt (p. 117), barite (p. 309), clay (p.
170), graphite (p. 344), gypsum (p. 244), magnesite (p. 355),
pyrite (p. 400), silica (p. 390), talc (p. 407),
and whiting.
Hematite.
Certain kinds of hematite, such as the Clinton ore

(see Iron Ores), are ground and sold under the name of metallic
paints, and much used for coating wooden surfaces and coloring
mortar.
The ores are sometimes roasted before grinding to improve
and durability. Although hematite deposits are wideand

sometimes of large size, the quantity of material showspread,
the
ing
necessary uniformity of color, freedom from grit, etc., retheir color
quired for mineral paint is small. Much crude material is supplied

by the Clinton ore mines at Clinton and Ontario, New York (8).
At some localities in northwest Georgia and southeast Tennessee the Clinton oolitic hematite occurs in beds too thin to be
now
mined
and
for iron ore,
but
its softness,
make it available for red

The following analyses show
color
high percentage of iron oxide
paint (3).
the composition of this material.
ECONOMIC GEOLOGY
372
Ochers may result from (5, 10) the leaching action of percolating waters and subsequent deposition; as residual products, formed
by the removal or solution of the soluble parts of the original rock,
leaving the insoluble portions, clay and iron oxide, to form the
:
different ocherous colored clays;
from the decomposition of rocks

of beds of pyrite;
by oxidation
rich in iron-bearing silicates;
by
by alteration of more
by replacement; by sedimentation.
alteration or decomposition of hematite beds;
compact forms
of
Distribution of
limonite;
Ocher.
Georgia and
Pennsylvania are the
largest producers of ocher, but California,
Vermont, and other
states help to swell the total.
In this state the ocher deposits occur in a

Georgia (5, 6, 10).
north-south belt, 8 miles long, lying east and southeast of Cartersville.
The ocher is limited to the Weisner (Cambrian) quartzite,
in
which
FIG. 121.
it
occupies an extensively shattered zone of similar posi-
Section showing relations of ocher, quartzite, and clay, near Cartersville,

Ga. (After Watson, Ga. Geol. Siirv., Bull. 13.)
tion to that of the residual clay derived

121).
The
following analyses represent
from the rock decay

its
composition.
ANALYSES OP GEORGIA OCHER
(Fig.
MINOR MINERALS
373
The average percentage of limonite in a number of analyses was

74.15 per cent for both the crude and refined ocher.
There is admixed with it about 20 per cent of clay and finely divided quartz
which cleansing will not eliminate. The ocher of this district
ranges from a dark to a light yellow color dependent chiefly on the
amount of admixed clay.
According to Watson (10), the Bartow County ocher deposits
have been formed by molecular replacement of the quartzite, and
subsequent weathering has resulted in the ocher bodies being inclosed in many cases in residual clays derived from the decay of the
original rock.
Hayes (5) states that the ocher forms a series of
irregular branching veins, extending in all directions, but often expanding into bodies of considerable size.
by Watson
It is believed
(10)
that the iron oxide of the ocher was
derived largely from the decay of surface rocks and carried downward by surface waters in the form of soluble ferrous salts, but that
some was probably contributed by
pyrite in the quartzite.
The
deposition may have been due to the carbon-dioxide solution of

ferrous carbonate meeting an oxidizing solution, resulting in a
precipitation of the iron and a solution of the silica of the quartzite.
The main use

of linoleum
is
and
of the Georgia yellow ocher is in the manufacture

It
oilcloths, especially in England and Scotland.
employed to a limited extent
The ocher
for paint
manufacture.
eastern Pennsylvania
Pennsylvania.
include the residual deposits of the Reading-Allentown district and
the bedded deposits of the Moosehead district. The first named
deposits
of
includes the principal ocher belt of Pennsylvania and lies in Berks

and Lehigh counties, where the ocher deposits occur as irregular
masses in a residual clay derived from the Shenandoah (CambroAssociated with the ochers are nodules and
Silurian) limestone.
geodes of limonite, as well as smaller quantities of turgite, ilmenite,
The product after washing, drying, and grindsiderite, and pyrite.
ing contains from 12 to 30 per cent Fe20sIn the Moosehead area a bed of soft, buff-colored shale, found at
the base of the
Mauch Chunk
sandstone (Lower Carboniferous),

grade,
and
mined
shale,
is
resting
on the Pocono
It is of low
for paint.
carries from 6 to 7 per cent ferric oxide.

sienna have been produced in small quantities in
and the product
Umber and
1
Van
Hise, Treatise on
Metamorphism,
p. 417.
ECONOMIC GEOLOGY
374
Illinois
and Pennsylvania, and sienna
tained from
New
in addition has
York.
ANALYSES OF MINERAL PAINTS FROM PENNSYLVANIA
been ob-
MINOR MINERALS
Below are given (I) an analysis of the crude ore
(7),
analysis of the roasted product (4).
375
and
(II)
ANALYSES OF SIDERITE PAINT "ORE" FROM PENNSYLVANIA
an
ECONOMIC GEOLOGY
376
Calcium Carbonate, in the form of chalk, known commercially as whiting

or paris white, is used as a pigment to alter the shade of other pigments
as a basis for whitewash.
Kentucky, Michigan and Missouri produced whiting in 1914, but all of it

was not used as pigment. Whiting may be prepared by grinding different
kinds of white limestone, but
it is
not as
as the artificially prepared material.
fine
grained or as light in weight
fine-grained rhyolitic tuff has been
Los Angeles County, Calif., for white pigment.

Paints sometimes classed as mineral paints are made
from other crude minerals, as follows: zinc white from zinc ore; white
lead, red lead, and orange mineral from lead; Venetian red from iron sulphate; vermilion or artificial cinnabar from quicksilver; chrome yellow
from chromite; cobalt blue from cobaltite.
produced
in
Other Paints.
Production of Mineral Paints.
The production
of mineral
paints, as well as the imports, are given below.
PRODUCTION OF NATURAL MINERAL PIGMENTS, 1909-1914, IN SHORT TONS
PIGMENT
MINOR MINERALS
PRODUCTION OF OCHERS IN CANADA, 1912-1914
YEAR
377
ECONOMIC GEOLOGY
378
commercial monazite varies between 3 and 9 per cent.
Although
grains of monazite are found scattered through many granites and

gneisses, still no occurrences of this type have thus far proven to be
of commercial value.
The economically valuable
deposits are
all
found in stream gravels, derived from the disintegration of monaMonazite is usually light yellow to honey
zite-bearing rocks.
yellow, red, or brown in color, has a resinous luster, a specific
gravity of 5.203 (Penfield and Sperry) and a hardness of 5 to
5.5.
It is
very
brittle.
Its gravity
and
color aid in its
ready
determination.
In the United States deposits of monazite sand have been found

in the granite and gneiss areas of North Carolina (2, 4) and South
Carolina (3), and these, together with deposits found in Brazil (1),
supply nearly the entire world's demand. A small quantity is also
obtained from southern Norway, as a by-product in feldspar mining.
The
following analyses indicate the composition of monazite
ANALYSES OF NORTH CAROLINA MOXAZITE
MINOR MINERALS
379
Where the monazite has been found
in the bed rock, it has been

pegmatized gneiss. In the ordinary gneiss,
and in the highly pegmatized gneiss, the monazite is far less abundant.
These occurrences in bed rock have not, however, proved
to be of commercial value, and the only important deposits are the
placers, and gravel beds in the streams and bottom lands, as well as
chiefly in a porphyritic
some surface soils, adjoining the rich gravel deposits.

In some areas the saprolite or rotted rock underlying gravel deposits has been washed with favorable results.
The monazite-bearing gravels range in thickness from one to two
feet, including overburden, up to 6 to 8 or more feet, and the monazite on account of its gravity has collected more abundantly in the
lower portion.
The
deposits are richest in those regions contain-
ing an abundance of granitic rocks, pegmatized gneisses, and schists,

while in the gravel itself, the presence of considerable quartz debris,
and fragments
of such rocks as pegmatite, granite, mica,-and cyanite
gneiss, are favorable signs.
In some cases the supply of monazite in the stream gravels may be

by wash from the hillsides which are underlain by residual soils containing monazite grains.
The monazite found in the pegmatized gneiss is believed to have
been derived from aqueo-igneous solutions passing through the
rock, and depositing and recrystallizing portions of it into the minreplenished
erals of pegmatite.
Monazite is usually separated from the gravels by a

washing process, and in addition magnetic separation has in some
cases been employed to separate it from the associated garnet,
magnetite, and quartz.
The value of monazite lies in the incandescent properties of the
oxides of the rare earths, cerium, lanthanum, didymium, and thorium, which it contains, and which are utilized in the manufacture
Uses.
of mantles for incandescent lights.
Production of Monazite.
The production
of monazite de-
maximum
of 1,352,418 pounds, valued at $163,908

in 1905, to 99,301 pounds, valued at $12,006 in 1910, since which
time there has been no production in the United States, the gas
been supplied by imports from Brazil.
mantle
clined from a
industry having
REFERENCES ON MONAZITE
1.
Dennis, Min. Indus., VI: 487, 1898.

Surv., Bull. 9,
1895.
(General.)
1003, 1903; and 1903:

S. Geol. Surv., Bull. 340: 272, 1908.
U.
2.
Nitze, N. C. Geol.
Pratt, U. S. Geol. Surv., Min. Res., 1902,

4. Sterrett:
(N. Ca. and S. Ca.)
1163, 1904.
3.
(N. Ca. and S. Ca.)
CHAPTER
MINOR MINERALS
XII
PRECIOUS STONES
WAVELLITE
PRECIOUS STONES
THE names gems and precious stones (I, 2) are applied to certain
minerals, which on account of their rarity, as well as hardness, color,
and luster, are much prized for ornamental use. The hardness is of
importance as influencing their durability, while their color, luster,
and even transparency affect their beauty. A distinction is some
times made between the more valuable stones, or gems (such as
diamond, ruby, sapphire, and emerald), and the less valuable, or

precious stones (such as amethyst, rock crystal, garnet, topaz,
moonstone, opal,
etc.).
Most gems are found in unconsolidated surface deposits representing either residual material or alluvium derived from it, and in the
latter their concentration and preservation are due to their weight
and hardness. When found in solid rock, the metamorphic and
igneous types are more often the source than the sedimentary ones.
Many different minerals are used as gems (1, 2), but only a few
of the important ones can be mentioned here, and the number of the
more valuable kinds found
in the
United States
is
very limited
(4, 12).
Every year, however, discoveries of one kind or another are
reported, and reference is usually made to these in the Mineral Re-
sources of the United States published annually

States Geological Survey.
by the United
Diamond.
This mineral, which is the hardest of all known
natural substances, is pure carbon, crystallizes in the isometric
system, and has a specific gravity of 3.525. It occurs in many
different colors, of which white is the commonest, and is found
either in basic igneous rocks or in alluvial gravels.
The massive forms, known as bort or carbonado,
have little or no
and are of value only as an abrasive.
The greatest number of diamonds come from South Africa, but
other deposits of commercial value occur in India, Borneo, and
cleavage,
Brazil.
380
MINOR MINERALS
in
381
In the United States a few scattered diamonds have been found

the drift or soil of the southern Alleghanies, California, Wiscon-
and Indiana, but they are all small (10, 12, 13, 15).
Arkansas. The only and first locality in North America where
diamonds have been found in place, is in Pike County, Ark.
sin,
(9, 13),
boro
where, near Murfreesareas
several
are
dotite
(Fig. 123).
of peri-
known to occur
The first diamonds
were found in 1906, and up

to 1913, approximately 1375
stones, aggregating about 550
carats, were reported to have
been recovered.
The sedimentary
this
area
rocks
of
consist of strongly
folded Paleozoic ones, overlain

by Cretaceous beds, and these
have been
intruded by the
peridotite.
This has in most
places disintegrated to a soft
whose topographic feanot diftures, however, do

fer from those of the Trinity
10
Bingen
sand
Peridotite
Map
FIG. 123.
area.
Trinity
Sandstone
formation
earth,
of
(After Miser,
Arkansas diamond
U.
<S.
Geol. Sure.,
Bull. 540.)
(Cretaceous) clay.
The residual clay derived from the peridotite is usually yellowish green above and bluish green below, the solid rock being in
some
cases as
much
as 30 feet deep.
10 Feet
Section in Arkansas diamond area.
FIG. 124.
South Africa
in
some
(5a,
respects
24a).
some
The Arkansas diamond occurrence resembles

There the gems have
South African ones.
(1) In northern Cape Colony;
localities, viz.:
of the
been discovered at several
(After Miser.)
ECONOMIC GEOLOGY
382
(2)
At
(4)
In
Jagerfontein, Orange Colony;

Africa.
(3)
near Pretoria, Transvaal;
and
German Southwest
In the Kimberley field, for example, the diamonds occur in volcanic

necks or "pipes" of kimberlite. These necks pierce a series of sandstones,
The
lavas, and shales, ranging from Carboniferous to Triassic in age.
upper part of the kimberlite is weathered to the so-called yellow ground,
while below it is the unoxidized rock or blue ground. The latter is the
material
now worked, and has
to
the diamonds can be extracted from
be disintegrated by weathering before

it.
The
pipes are to be regarded as vents filled with the products of exand the diamond crystals disseminated through this, may
be crystallizations from the magma.
plosive eruptions,
The Premier mine, where the

berley, has yielded the Cullinan
conditions are similar to those at
diamond,
the largest ever found,
Kim-
weighing
3024f carats, and measuring 4 by 2 inches.

The German Southwest Africa deposits are unique in that the diamonds
occur in a windblown sand and gravel resting on the crystalline bed rock.
Their exact source, whether from the crystalline rocks of the district, or a
hypothetical basic igneous rock now below sea-level, is open to doubt (56,
24a).
British Columbia (7a).
A highly interesting, but not commercially
important occurrence of diamonds has been found at Olivine Mountain,
in the Tulameen district of British Columbia.
The rock is a serpentinized
peridotite, containing small segregations of chromite,
and
it
is
with, these
that the diamonds are found, forming without doubt original constituents
of the igneous mass.
They are all small, not larger than a pin head, of
yellowish to brownish color, and partly or wholly opaque.
found in the neighboring stream gravels.
Origin.
The
origin
of
liie
few have been
diamond has provoked much discussion
of successful attempts have been made

These indicate its formation by crystallization
from a fused magma, which in most cases has a composition resembling
As corroborative of this we have the occurrence of South
peridotite.
African diamonds in or near volcanic pipes of peridotitic character, and
Lewis has suggested that the stones were formed by the solvent action of
the molten peridotite magma on carbonaceous shales. Some have disputed this idea, and believe that the diamond is an original constituent of
the magma, from which it crystallized on cooling. As opposed to an igneous
origin is the statement of G. F. Williams, that he found an inclusion of
apophyllite (a highly hydrous mineral) in a Kimberley diamond. The
occurrence in British Columbia, already referred to, seems to leave little
doubt as to a possible crystallization from a magma. All diamonds do not
occur in peridotite, for in Brazil hydromica schists and quartzite may
contain them, while certain Indian ones appear to have been derived from
pegmatite, and some Australian ones in hornblende-diabase.
The most that can perhaps be said is that, while much of the evidence
indicates an igneous origin, the diamond has not necessarily been obtained
in all cases from the same kind of magma.
among
scientists,
to produce
it
and a number
artificially.
MINOR MINERALS
Emerald.
aluminum
This
383
gem is a variety of beryl,
essentially a glucinumIts hardness is 7.5 to 8, and its specific

gravity
Its brilliant green color is attributed
by some to chro-
silicate.
2.5 to 2.7.
mium, by others to organic matter. Brazil, Hindustan, Ceylon,

and Siberia are all important sources. In the United States a few
have been found in western North Carolina (12, 15) in gravel deFlawless emeralds are very rare, and equal in value to
posits.
diamonds.
Aquamarine and
Brazilian emerald
is
oriental cat's-eye
are also varieties of beryl.
a green variety of tourmaline, and
lithia
emerald
an emerald-green spodumene.
Gem
Beryl.
New
beryl
has been
England, and while at some
found at many localities in

it has been obtained as
of these
an accessory mineral in feldspar mining, at others the veins have

been worked for the gem mineral alone. Thus in Connecticut
golden beryl has been obtained near New Milford, and good
aquamarine near East Hampton. Other localities have been
worked in Maine, Massachusetts and New Hampshire. 1
Garnet.
Of the several varieties of garnet, three are well
-
known
as
gem
stones, viz., the precious garnet, or almandite,
Bohemian garnet, or pyrope, and manganese garnet, or spessartite.

The first two are of deep crimson, the last of orange-red or
India is the main source of supply. All
light red-brown color.
three varieties mentioned are found in the United States, but
there is a regular production only of the pyrope from Arizona and
New
Mexico, and a purple-red garnet known as rhodolite from

North Carolina (4, 12, 15).
Those found in the southwest (22) have for many years been
Clear red garnets associated
collected by the Navajo Indians.
with peridot gems, which have been weathered out of basic
igneous rocks, have been found at several places around and north
of Fort Defiance, Arizona, but those obtained from these localities
are small and not worth cutting. The supply of gem garnets
comes from close to the Utah-Arizona line, at a point 12 miles
southwest of the junction of the Chin See Valley and San Juan
River in Utah. In this region, which is underlain by sandstone
of probable Triassic age, pierced by numerous basic igneous rocks,
the garnets are found chiefly in a coarse, unconsolidated drift or
gravel layer, associated with feldspar, diopside, quartz, and
igneous rock fragments.

1
The garnets range
Min. Res., U.
in
size
S. Geol. Surv., 1913, p. 656.
from small
ECONOMIC GEOLOGY
384
grains to others over 3 centimeters in diameter, but the

are not over 12 millimeters across.
gem
stones
Opal, which is hydrous silica chemically, is amorphous, with

conchoidal fracture, yellow, red, green, or blue color, and often
showing considerable iridescence.
The
varieties recognized are
and common opal. The finest

are
obtained
from Hungary. Others
of
precious opal
examples
are also found at Queretaro, Mexico, and in Oregon and Wash-
the precious opal,
fire opal, girasol,
The United States production is small, although it is

there are many scattered occurrences in the igneous
that
thought
rocks of Washington, Idaho, Oregon, California, Nevada, and
ington.
Utah
(4, 12).
considerable prospecting was done in the opal

1913,
field of Virgin Creek, Humboldt County, Nevada, a region that
1
In
was discovered in 1908. The formations consist of tuffs, ashes

and rhyolitic lavas, which have been broken by block faulting
and tilting, and the opal occurs in the ash beds, mostly associated
with the petrified wood. It is found as casts of different parts of
the trees, and as coatings and filling in cracks in the silicified wood.
This name
Peridot.
is
applied to a deep olive-green variety of
hardness (6.75) as
magnesium and iron. Peridot has a low

compared with other gems, while its specific
gravity, 3.3 to 3.4,
is
chrysolite, a silicate of
relatively high.
in two regions in Arizona (22) viz. north of
Gem peridot is found
Fort Defiance in the Navajo Indian Reservation, and near Rice

White Mountains Apache Indian Reservation. In the
in the
is plentiful, and is found associated with

These are monzonite porphyry, orthoclase basalt,
and peridotite agglomerate. The peridot, which appears to have
been derived from the agglomerate, is found in the soil, and asso-
former district the peridot
volcanic rocks.
ciated with
it
are such minerals as garnet, diopside, quartz, calcite,

Gems of 1 to 2 carats' weight are fairly abundant,
titanic iron, etc.
and some
of 3 to 4 carats are found.
color are
commonest.
Those of dark yellowish-green
In the Rice district peridot is found not only in the original

basalt rock matrix, but also loose in the soil.
A red, transparent variety of corundum (A1 2 3 ), having

Ruby.
a hardness of 9 and a specific gravity of 4. The most valuable color
in ruby is a deep, clear, carmine red.
Rubies of large size are
1
Merriam, Science, n.
Min. Res., 1913, p. 677.
s.,
XXVI:
380, 1907,
and
Sterrett,
U.
S. Geol. Surv.,
MINOR MINERALS
385
scarce, so that a 3-carat stone of
good color and flawless is worth

diamond of the same size. The best
ones come from Burma. In the United States
they have been
found in the stream gravels of Macon County, North Carolina, but
the production is not a steady one. Those found in Arizona and
several times as
much
as a
other western states are not true rubies, but a variety of garnet
(4, 12, 15).
is a blue, transparent
variety of corundum (A12 3). It
of slightly greater hardness and specific gravity than the
ruby,
though of similar composition. Sapphires of good color and size
Sapphire
is
more common than rubies and cheaper. The best sapphires,

come from Siam. In the United States they have been found in
the gravels of Cowee County, North Carolina, but Yogo
Gulch,
Montana, is now the main source of domestic supply. They range
in weight from under 1 up to 4 or 5 carats (4, 12, 18).
The Montana sapphires were first found in gravel bars on the
are
Missouri River, but subsequently they were discovered in dikes

of basic igneous rock cutting Carboniferous (?) limestone in southwestern Fergus County. The rock is of somewhat basic character
belonging to a type known as monchiquite, and the sapphires are
obtained from the somewhat decomposed portions of the dike.
There are two companies, both operating on the same dike, which
has a width of 10 to 20
feet,
and has been traced
for a distance of
5 to 6 miles.
A remarkable transparent lilac-colored and pale

Spodumene.
pink to white spodumene, known as Kunzite (14) has been found in
California not far from the rubellite locality, and occurring in a
pegmatite dike, where it is closely associated with gem tourmalines.
This is a fluosilicate of alumina, crystallizing in the
Topaz.
orthorhombic system, with a hardness of 8, specific gravity of 3.5,
vitreous luster, and yellow, green, blue, red, or colorless.
It occurs
in gneiss or granite, as well as in other metamorphic or igneous rocks,
and is associated with beryl, mica, tourmaline, etc. It is also found
in alluvial deposits.
The best gem stones come from Ceylon, the
Urals,
and
Brazil.
In the United States they have been found in
small quantities in Maine, Colorado, California (12), and Utah.

In Utah topaz (17) is found in the Thomas range of mountains about
40 miles north of Sevier Lake, at a locality known as Topaz Mountain. The
transparent crystals occur in lithophysae in rhyolite, and vary from colorless to wine color.
Rough opaque crystals are scattered through the solid
The crystals are believed to have been formed by vapors or solurhyolite.
ECONOMIC GEOLOGY
386
tions contemporaneous or nearly so with the final consolidation of the rock.

In the weathering of the rock the crystals fall out and become mixed with
the soil, the colored ones fading on exposure to the light.
Topaz is obtained from pegmatite veins near Ramona, San Diego County,
where
it
occurs in pockets in albite and orthoclase.
yellow, sea-green,
and sky-blue, some
of
them being
The topazes
are white,
of large size (14).
This is a complex silicate, of aluminum and

with
usually varying amounts of iron, magnesium, alkalies,
boron,
and water. It has a hardness of 7 to 7.5 and a specific gravity of
Tourmaline.
2.98 to 3.20.
The
color is variable,
and
this variation
may exist
in
the same crystal.
The opaque, black, or brown tourmaline is a somewhat common

mineral in many metamorphic rocks, as well as in granite and other
eruptive rocks, but this variety has no value as a gem.
Gem tourmalines are, however, rather rare, being known in Brazil,
Russia, and Ceylon, and in this country in the states of Maine,
Connecticut, and California.

are
most highly
Of the gem tourmalines the red ones
prized, especially the darker ones;
the green ones
are usually dark green.

A large number of green tourmalines have been obtained from a
pegmatite granite at Paris, Maine, and

tending from Auburn to
Newry
(23).
many
are found in a belt ex-
The gems here
are likewise
found in pegmatite, and are associated with beryl.

An interesting and important occurrence of red tourmaline
(rubellite) has been worked at Pala, San Diego County, California.
The crystals here form radiating groups in lepidolite and the earlier
discovered ones were clear enough for cutting. Valuable crystals,
many of gem character, have since been found in pegmatite veins
near Pala, and near Mesa Grande (14).
Turquoise is a massive hydrated aluminum copper phosphate,
Its hardness is 6,
of waxy luster, blue to green color, and opaque.
and
specific gravity 2.75.
in volcanic rocks.
The
It usually occurs in streaks and patches

best varieties are obtained from Persia,
but it is also obtained from Asia Minor, Turkestan, and Siberia.

In the United States turquoises are found in the Los Cerillos
Mountains near Santa Fe, New Mexico, and Turquoise Mountain,
Arizona, as well as in Colorado.
It is interesting to note that turquoise was hardly known in the
United States in 1890, but now a considerable supply comes
from the southwestern states and
The production
territories (I6a, 22, 25).
of turquoise in the United States has at dif-
MINOR MINERALS
387
come from New Mexico, Nevada, Arizona, California,

and Colorado.
Turquoise mines have been operated in the Burro Mountains,
ferent times
15 miles southwest of Silver City, New Mexico.

The country
rock of granite, which is cut by andesite-porphyry, andesite, and
dacite, is
much
fissured zone,
altered, and the turquoise is found in a vein or

which contains kaolinized feldspar and secondary
quartz.
In this strip, which is 40 to 60 feet wide, the turquoise occurs as

veins and nuggets, the former filling cracks in the granite
to f
inches wide, and the latter in the kaolin. The veinlets often cross
and indicate successive periods
of deposition.
A diversity of opinion exists regarding the origin of the turquoise.

Silliman (Amer. Jour. Sci., 1881, July, p. 67) believes it to have
been formed by heated water and vapors, which destroyed the original character of the rock and produced new compounds.
Clarke
and Diller suggested that the turquoise represents a replacement of
the apatite of the granite. Johnson (16 a) advanced the theory
that gases played a role in the decomposition of the rock, and called
The
attention to the association of fluorite with the turquoise.
he
was
derived
from
the
the
of
alumina
thinks,
turquoise,
feldspar,
the phosphorus from the apatite, and the copper from cupriferous
solutions which formed the ores in that region.
Zalinski (25) believes that hot solutions, coming from below,
caused a kaolinization of the granite, the
silica set free in this
connec-
tion being deposited in cracks and fractures with the turquoise.

Solutions carrying aluminum phosphate rose along fissures parallel
with the walls, while the copper solutions came along an intersectIntermingling of the two solutions formed the turquoise.
ing series.
Mohave County, Arizona
(22), the turquoise is found in the

and
intrusive
granite, both of which have been
porphyries
younger
more or less altered, especially around the turquoise deposits.
This alteration consists of kaolinization, but there has also been
In
silicification, as shown by a deposition of quartz in joints and

between the grains. Some of the turquoise seems to have been
derived from the kaolin by the addition of phosphoric acid and
copper, but much of it has been deposited from solution, as it occurs
as seams and veinlets, as well as in patches or streaks in quartz
seams and veinlets. The nodular turquoise is less common.
The Colorado turquoise deposits are associated with trachyte,
but they show relations similar to the Arizona material.
some
ECONOMIC GEOLOGY
388
In the district of northeastern San Bernardino County, California, where several large mines have been operated, the turquoise occurs in a coarse porphyritic granite, and a monzonitic
(?)
These have been fractured, and then sericitized and

well as stained with limonite.
Later solutions
as
kaolinized,
of
the
elements
carrying
turquoise passed through the same
fissures where kaolinization occurred and deposited the turquoise
in seams and veinlets, as well as in nodular masses in the kaolinized and sericitized rock. 1
This mineral alone is not used as a gem stone,
Variscite.
but it is cut with its associated matrix. This mixture, which is
sometimes called amatrice (26), is composed of variscite, wardite,
and probably other associated minerals such as chalcedony and
porphyry.
quartz.
The
first
two are hydrous phosphates
showing varying shades of

and having a hardness of
consists of chalcedony and
them yellowish gray and
value of the material
lies in
of
green, of compact, tough
aluminum,
character
The matrix
quartz with other minerals, among
white phosphates. The decorative
4 and 5 respectively.
the variety and arrangement of
its
colors.
The United States produces

Production of Precious Stones.
of different kinds of gems and precious stones, but the
total output is by no means large.
Moreover, those kinds most
used are produced in but small amounts. The collection of aca
number
curate statistics of production is, for several reasons, quite difficult

and therefore the output has to be estimated in some cases. The
figures of production for 1912 to 1914 are given
on the opposite
page.
The imports of precious stones into the United States for 1909 to
1914 as reported by the Bureau of Statistics is given below.
IMPORTS OF PRECIOUS STONES INTO THE UNITED STATES, 1909-1914
YEAR
MINOR MINERALS
389
PRODUCTION OF PRECIOUS STONES IN THE UNITED STATES IN 1912-1914
ECONOMIC GEOLOGY
390
REFERENCES ON PRECIOUS STONES
GENERAL WORKS.
tion
L.
by
Minerals.
1.
J.
Edelsteinkunde.
Bauer,
(Chicago, 1903.)
(Leipzig,
1896.
Transla-
Farrington, Gems and Gem,

3. Goodchild, Precious Stones.
(N. Y..
London.)
Spencer,
2.
Kunz, Gems and Precious Stones of North America. (N)

5. Streeter, Precious Stones and Gems.
Y., 1892.)
(London, 1892..
5a. Stutzer, Die Nicht-Erze, Berlin, 1911.
(Diamond, general.) 56
Boise, Min. Mag., XII: 329, 1915.
(German S. W. Africa.)
SPECIAL PAPERS. 6. Baskerville, Science, n. s., XVIII: 303, 1903. (Kunz4.
1908.)
7.
ite.)
monds
monds,
Blatchley, Ind. Dept. Geol. Nat. Res.,
in drift, Ind.)
Brit.
Col.)
XXVII:
11.
(Dia-
7a Camsell, Econ. Geol., VI: 604, 1911. (Dia8. Clarke, U. S. Geol. Surv., Bull. 491:
306,
Derby, Jour. Geol., XIX: 627, 1911.

Hobbs, Jour. Geol., VII: 375, 1899.
11. Kunz., U. S. Geol. Surv., Min. Res., 1905:
(Wis. diamonds.)
12. Louderback, Univ. Calif. Pub., V,
1249, 1906.
(Opal, Ore.)
No. 23: 331, 1909. (Benitoite.) 13. Kunz and Washington, Amer.
Inst. Min. Engrs., Trans. XXXIX:
(Ark. diamonds.)
169, 1908.
14. Kunz, Cal. State Min. Bur., Bull. 37, 1905.
(Calif, gems and
ornamental stones.) 15. Kunz, N. Ca. Geol. Surv., Bull. 12, 1907.
16.
(History N. Ca. industry.)
Kunz, Amer. Jour. Sci., IV: 417,
1911.
(Diamond
genesis.)
(Origin Brazil diamonds.)
9.
10.
'
1897.
(Mont, sapphire.) 16a. Johnson, Sch. of Mines Quart., XXIV:
166. MacFarlane, Eng. and Min.
(N. Mex., Turquoise.)
493, 1903.
16c. Miser, U. S. Geol. Surv.,
Jour., Oct. 28, 1911.
(Opals, Mex.)
Bull. 540:
16d. Paige, Econ. Geol. VII:
382.
(Ark.)
534, 1914.
17. Patton, Geol. Soc. Amer.,
(Turquoise, Burro Mts., N. M.)
17a. Penrose, Econ. Geol.,
(Topaz, Utah.)
177, 1908.
18. Pirsson, Amer. Jour.
(Premier diamond mine.)
275, 1907.
1912.
Bull.
II:
XIX:
IV: 421,1897.
(Petrography
Nat. Acad. Sci., XII, Pt. Ill, 1915.
Sci.,
Montana sapphire rock.)
18o. Pogue,
19. Pratt, U. S. Geol.

(Turquoise.)
20. Pratt and Lewis, N. Ca.
(Sapphire.)
Surv., Bui. 269, 1906.

Geol. Surv., I:
180, 1905.
(Ruby.) 21. Purdue, Econ. Geol., Ill:
22. Sterrett, U. S. Geol. Surv., 1908.
(Ark. diamonds.)
525, 1908.
(Moss agate, Wyo.; Peridot, Ariz.;
Chapter on Precious Stones.
23.
Ariz.; Turquoise, Ariz, and Colo.; Variscite, Utah.)
Wade, Eng. and Min. Jour., June 5. 1909. (Tourmaline and Beryl,
Me.
24. Watson, Min. Res. Va., 1907: 386.
(Amethyst, Va.) 24a.
Williams, G. F., Diamond Mines of South Africa (London, 1902.) 25.
Zalinski, Econ. Geol., II: 464, 1907.
(Turquoise, N. Mex.) 26. Za(Utah Amatrice.)
linski, Eng. and Min. Jour., May 22, 1909.
Garnet,
1
QUARTZ
Although this material has been briefly referred to under abraand glass sands, it is sufficiently important to require treat-
sives
ment
as a special topic.
MINOR MINERALS
391
is the second most abundant constituent of the earth's

and
crust,
quartz, of which it is an important ingredient, is the
most abundant of all minerals, but varies greatly in its mode of
occurrence and uses. Thus some varieties, such as rose or smoky
Silicon
quartz, amethyst, etc., are used as gems.

Quartz in the form of
is employed for molding (p. 335), building, glass-making
sand
In the form of sandstone

(p. 340), and pottery manufacture, etc.
and quartzite (p. 156) it is of value as a structural material.
The forms of quartz considered here are the massive crystalline
quartz (often known as vein quartz), flint, and quartzite used for
purposes other than building or paving.
This form of quartz, which is white, or less
Vein Quartz (1-3).
often rose or smoky, occurs in veins or dike-like masses, usually in
metamorphic rocks. It may be of high purity, or may be mixed

with feldspar, mica, etc., as an ingredient of pegmatite, in which case
Vein
it is obtained as a by-product in the mining of feldspar.
is produced in Connecticut, New York, Pennsylvania, and
Maryland. A crystalline quartz, not of vein character, obtained in
southern Illinois is referred to under Tripoli (p. 412).
This rock is quarried at a few localities for special
Quartzite.
Thus in Cherokee County, North Carolina, a vitreous
purposes.
Cambrian quartzite has been quarried for use as a flux in copper
smelting.
Large quantities of a hard brittle quartzite have also
been quarried near Wausau, Marathon County, Wisconsin, the
ground product being used for sandpaper and other abrasive pur-
quartz
poses, filters, bird grit,
wood
filler, etc.
It analyzes 99.07 per cent
silica.
This term
Flint or Chert.
compact texture and
is applied to lusterless quartz of very

conchoidal fracture, which often forms
nodules in limestone or chalk.
In some cases these concretions
represent silicified fossils. Flint nodules are found in many

formations in the United States, but little of the domestic mate-
may
rial
true
has been utilized except for road metal.

flint
demanded by
this
The
entire supply of
country for special purposes is obtained
from France, England, Norway, and even Greenland, being brought

over as ballast.
much
The
of the supply
is
smaller nodules are used in tube mills, but

and then ground for use
calcined to whiteness
in pottery manufacture.
Uses of Quartz.
Quartz
is extensively used in pottery manufacture to diminish the shrinkage of the ware in burning, and for this
In recent
purpose it should have under 1 per cent of iron oxide.
ECONOMIC GEOLOGY
392
years quartzite and sandstone have been more used than vein
It is also employed in the manufacture of wood filler,
quartz.
scouring soaps, sandpaper, filters, and tooth powders.
Blocks of massive quartz and quartzite are employed as a filter for
acid towers.
Quartz is also used as a flux in copper smelting and
Much chemical
in the manufacture of silicon and ferrosilicon.
paints,
ware
is
now made
of fused quartz.
PRODUCTION OF QUARTZ IN THE UNITED STATES, 1909-1913, IN SHORT
TONS
MINOR MINERALS
393
Of these two the former is the more important, but the latter is the
more valuable, as the strontium salts can be more easily extracted
from it.
Both
and
celestite
strontianite
have been found at a number of
the United States, but seldom in large quantities. One

important deposit of celestite has been found in limestone caves near
Put-in Bay, Strontian Island, in Lake Erie, and in opening up the
localities in
cave 150 tons of the mineral were taken out. Similar occurrences
have been found in limestones in other states, but none of them
have any commercial value.
Nearly all the strontium salts now used in the United States are
imported from Germany, the crude material being obtained in part
from Westphalia, Germany, and also from Thuringia, Germany,
and Sicily.
Uses.
Strontium salts are used in sugar refining, in fireworks
manufacture, and to a small extent in medicine.
REFERENCE ON STRONTIUM
1.
Pratt, U. S. Geol. Surv.,
Min. Res., 1901: 955, 1902.
SULPHUR AND PYRITE

These two minerals are discussed in the same chapter because
both serve as sources of sulphur or sulphuric acid.
SULPHUR
Native sulphur
may be formed in several different ways as follows
Solfataric Type.
Sulphur is often found in fissures of lava and
1
tuff around many active and also extinct volcanic vents.
When
thus formed as a volcanic sublimate it may be a product of reactions

between sulphur dioxide and hydrogen sulphide. It may also be
formed by incomplete combustion of hydrogen sulphide, probably

= 2 H2 + 2 S. This latter change probas follows: 2 H 2 S +
2
occurs
at
least
a
short
distance below the surface, where oxygen
ably
is deficient, as at the surface the H^S may form HaSO^
Deposits of the solfataric type are rarely of commercial importance, but they are worked in Japan, and have also been worked in
the crater of Popocatepetl in Mexico.
Mineral Spring Deposits.

around mineral springs,
posit
1
Ferric chloride
is
Sulphur
its
is
not an
uncommon
de-
deposition being due to imperfect
sometimes deposited around fumarolic vents, and might, owing
to its similar color, be at first mistaken for sulphur.
ECONOMIC GEOLOGY
394
oxidation of hydrogen sulphide, the sulphur appearing in the

spring waters as a whitish powder. It has been noticed, however,
that the associates of this type of sulphur deposit are often some
form of lime carbonate, or gypsum, and that the sulphur depositing springs sometimes rise through fissures in limestone, leadl
ing to the belief that a reaction like the following may occur:
or
The calcium hydrosulphide formed will yield calcium carbonate

gypsum on the escape of the H 2 S as follows
:
Ca(SH) 2 +2O 2 +2H 2 O = CaSO 4 -2H 2 0+H 2 S;
Ca(SH) 2 +CO 2 +H 2 O
=CaCO 3 +H 2 S.
Ihis accounts for the travertine and gypsum found with some
mineral spring deposits (p. 397). It is possible also that some of
the sulphur is deposited by sulphur bacteria. 2 These have the
H2 S
H 2 S04, and retaining free sulphur

an excess of H 2 S. The H 2 S04 formed
will in turn attack calcium bicarbonate, which the cell takes up
from the water and converts it into calcium sulphate. Sulphur
under favorable conditions may also be carried in the colloidal
power
of oxidizing
in their cells,
if
there
to
is
3
form, and be later precipitated.
This type, which is of world-wide
Gypsum Type (3e, 8).
of its constant association with
is
so
called
because
distribution,
with gypsum. Limestone, marls, and bituminous matter are

The Sicilian and Louisiana deposits are wellalso found with it.
known members of this group, and are referred to on pages 398 and
396.
and
Because of
its
lack of association with volcanic
activity
sedimentary formations, the true explanMost of

ation of its origin has been somewhat difficult to find.
the theories have been advanced in connection with a study of
the Sicilian deposits, and may be briefly stated as follows
1. The sulphur is thought to have been formed by the reducing
action of bituminous matter on gypsum according to the following
close relationship to
reactions
XVI:
Bechamp, Ann. chim.
Winogradsky, Botan. Zeit,, XLV, No. 31-37, 1887.

Raffo and Marneini, Zeitschr. Chemie Ind. Kolloide, IX:
phys., 4th ser.,
234, 1869.
58, 1911.
MINOR MINERALS
CaSO 4 +2C = CaS+2CO 2
395
CaS + CO 2 + H 2 O = CaCO 3 + H 2 S
= H 2 O+S.
This theory was
first
1
suggested by G. Bischof, and
is still
held
by many.
2.
Stutzer
(8a)
has suggested that the sulphur
sedimentary origin.
structure;
(6)
He
bases his belief on:
is
of purely
(a) Its stratified
the interstratification with limestone, and in the

absence in the gypsum; and (c) the
Sicilian deposits at least, its
presence of interbedded clay layers, which would prevent circulation, and preclude the deposition of the sulphur by permeating
waters.
In accordance with this view he assumes that decaying organisms in the water yielded hydrogen sulphide, or that it might
have been formed by the action of hydrocarbons on calcium sulphate. The oxidation of the hydrogen sulphide was brought
about either by the oxygen of the air, or by sulphur bacteria
(p. 394).
third theory is that the hydrogen sulphide was supplied

cold springs discharging into fresh-water lakes,2 or by hot
3
Tings flowing out over the ocean floor.
3.
4.
Hunt
(3o), after
noting that the sulphur of Sicily forms basin-
ike deposits, underlying the more continuous gypsum which contains occasionally lens-shaped masses of secondary sulphur, suggests the following:
The sulphur was collected in small basins, whose water had a

comparatively high average temperature, and a high sulphate
content. Bacterial reactions extending over a period of years
caused a copious production of H 2 S from decomposition of sulphates,
and reactions similar to those mentioned under Mineral
393), might cause a simultaneous precipitaand calcium carbonate. Some of the sulphur
would, however, be absorbed by the Ca(SH) 2 forming an unstable
poly sulphide, which would yield copious precipitations of free
sulphur from time to time. Continued evaporation of the basin
waters eventually rendered them so saline as to check bacterial
action and also precipitate the overlying gypsum.
Spring Deposits
(p.
tion of sulphur
1
2
3
Chem. u. Phys. Geol. II: 144, 1851.

A. von Lasaulx, Neues Jahr. Min., 1879, p.
G. Spezia, Neues Jahrb. Min. 1893,, I: 38.
490.
ECONOMIC GEOLOGY
396
In the ease of the Louisiana deposits at least, Harris has

suggested ascending hot waters as the source of the sulphur.
5.
Metallic Sulphide
Type
(4).
Sulphur
may
result
from alteration of pyrite,
marcasite, or related sulphides, possibly through action of bituminous matter.

Gypsum is a common associate. No deposits of economic value have been
formed
manner.
in this
Louisiana and
Distribution of Sulphur in the United States.
Texas are the most important producers, smaller quantities coming
from other western states, especially Wyoming.
The deposits of sulphur found in this state
Louisiana (4, 5, 10).
are the most important domestic source of this material.
They
occur in Calcasieu Parish, and were discovered as early as 1868 in
boring for oil and gas at the head of Bayou Choupique, 15 mile,?
west of Lake Charles.
The bed
which is of Cretaceous age (Harris and

300 to 400 feet below the surface, is over 100 feet
of sulphur,
lies
Veatch),
and is underlain by gypsum and salt. It is supposed by

some to have been derived from gypsum, but Harris suggests the
thick,
possibility of its precipitation
under
from ascending hot waters
(.see
Salt, p. 210).
Owing
to the quicksand-like character of the overlying beds,
attempts to sink a shaft to the deposit were unsuccessful. It is

now obtained by pumping superheated steam down through pipes,
melting the sulphur, and drawing it to the surface, where it is
discharged into vats to cool and solidify.
A similar deposit of sulphur is found near Bryan Heights,

Brazoria County, Texas. It is in one of the structural domes so
characteristic of the Mississippi embayment and referred to under
Oil (p. 106).
Utah
(6).-
Sulphur of the solfataric type was mined at Sul-
Utah for some years. In this district there

phurdale
found
a
series
of
are
rhyolites and andesites, overlain in places
in central
by basalts, the whole resting probably on Paleozoic sediments.

The sulphur, which occurs in a soft rhyolitic tuff (sometimes
called
gypsum), sometimes forms cylindrical masses or cones 10
to 15 feet in diameter, and with a rudely radial structure, but

most of it is found as a dark-colored impregnation or cementing
substance of the
tuff.
Occasionally there are seen branching veins of nearly pure yellow

sulphur, with a banding parallel to tke walls, and these may repre-
MINOR MINERALS
397
sent fissure fillings from solution, since acid water partly filled with
yellow sulphur issues from the fissures.
The crude material varies greatly

some showing as much
in richness,
as 80 per cent sulphur, but rock running as low as 15 per cent is market-
An
able.
analysis of the sulphur
from the retorts yielded: S, 99.71;

nonvolatile matter (SiO2, Fe20s,
etc.),
at 100
.23; free
S0 3
tr.;
moisture
C., .06.
volcanic origin
is
suggested for
the sulphur, because of its close

association with volcanics, and the
position of the beds along a fault
Gas now escapes from the

deposits in large volumes, and hy-
line.
drogen sulphide boils up through

water standing in the workings.
The sulphur may therefore have
been precipitated by the oxidation
of the hydrogen sulphide, which is
presumably of volcanic
origin.
Oxi-
dation of the sulphur may give 80s

and this by reaction with water,
H^SOi. Analysis of water issuing

from the beds shows sulphuric acid.
Native sulphur has
Wyoming.
in
been mined
Wyoming near Cody
near
Thermopolis (11), the
(12), and
at the two localoccurrence
of
mode
At the
ities being almost identical.
latter locality the deposits are found
Embar (middle Carwhich immelimestone

boniferous)
travertine
a
underlies
deposit
diately
in the altered
(Fig. 125).
The sulphur
occurs in small yellow
crystals filling veins or cavities in
the rocks, and in massive form as a replacement of calcium carbonate

by sulphur, the original structure of the limestone being retained.
ECONOMIC GEOLOGY
398
The
distribution of the sulphur appears to be very irregular,
and
confined to those portions of the limestone surrounding the channels of the hot springs that deposited the travertine.
The attempted explanation of the origin of the deposits is that surface
Marl
Silicified
Gypsum and bituminous marl
iForaminiferous marl
limestone
Sulphur bearing bed
FIG. 126.
Section in Sicilian sulphur deposits.
(After Mottura,
from
Stutzer,
Die Nicht-Erze.)
way downward along the sandstones from the

Owl Creek Mountains (Fig. 125), and came into contact with some
waters worked their
uncooled body of igneous rock, which not only heated them, but
also supplied them with hydrogen
Following this they passed
sulphide.
upward through the much-fractured

beds of the anticline with which the
deposits are
associated.
As these
waters approached the surface, the

sulphur was precipitated by oxidation, or by other processes mentioned
under Mineral Springs Deposits (p.

Hot springs carrying both
393).
H2& and CO2 exist there at present.
The depth
FIG. 127.
ing
Banded sulphur-bear-
rocks from
Sicily; black,
sulphur;
dotted,
limestone;
white, calcite.
(From Stutzer,
Die Nicht-Erze.)
Other States.
(1),
and California
two
of the deposits at these
localities is
but
not believed to be
the rich
pockets the
sulphur may form 30 to 50 per cent
of the rock.
great,
in
Sulphur deposits have been worked in Colorado, Nevada

(2).
In the Sicilian sulphur-producing region ^he sedimentaries

include (1) Sands, sandstones and shell breccia of Upper Pliocene; (2) Foraminiferal limestone of Lower Pliocene; and (3) Upper Miocene sulphur-bearing
Sicily (3a, 8a).
MINOR MINERALS
series, consisting of: (a)
399
an upper gyspum member with occasional lenses of
secondary sulphur, and (6) a series of beds of sulphur-bearing limestone, separated from each other by bituminous, salty clays and shales. The individual
in thicksulphur beds may vary from one to thirty (exceptional) meters
also
Associated with the sulphur are celestite and calcite, less often barite,
bituminous matter. The whole series has been disturbed by folding
and
faulting.
ness.
The most important use of sulphur is for

Uses of Sulphur.
of
the manufacture
sulphuric acid and in paper manufacture. Some
in
is also used
making matches, for medicinal purposes, and in
making gunpowder,
fireworks, insecticides, for vulcanizing india
rubber, etc.
In recent years pyrite has largely replaced sulphur for the manufacture of sulphuric acid, and the increase in price of Sicilian sulphur
has helped
this.
greater portion of the world's supply of sulphur is obtained

Sicily, the United States consuming the largest amount.
The
from
Production of Sulphur.
The sulphur industry
of the
United
grown rapidly in the last few years, and in 1907, for the
first time in its history, the value of the importations fell below the
States has
million dollar mark, due to the great decline in the imports of crude
Louisiana continues to be a great producer, and the comsulphur.
the product from this state with imported Sicilian mateof
petition
rial
has reacted somewhat disastrously on the latter.

for 1909 to 1913 is given below.
The production
SULPHUR IMPORTED AND ENTERED FOR CONSUMPTION IN THE UNITED STATES,

1910-1914, BY KINDS, IN LONG TONS
YEAR
ECONOMIC GEOLOGY
400
The imports came mainly from
The exports
Italy and Japan.
to 98,153 long tons, valued at $1,807,334, this
being 72,018 long tons in excess of the import. These figures
indicate that the country is producing more than enough sulphur
in 1914
amounted
to supply its
own
needs.
REFERENCES ON SULPHUR
1.
Adams, U.
Calif.
U.
S.

Min. Bur., Bull. 38:
S.
State
Dammer and
3a.
36. Hess,
Utah.)
U.
3c.
Tietze,
497,
1904.
(Nev.)
354,
576, 1916.
1906.
(Calif.)
(Origin,
I: 85,
2.
Aubrey,
3.
Clarke,
many
references.)
1913.
(General.)
530: 347, 1913.

(San Rafael Canon,
Hewett, U. S. Geol. Surv., Bull. 540: 477, 1914. (Park
3d. Hewett, Ibid., Bull. 530: 350, 1913.
(Sunlight Basin,
S. Geol. Surv., Bull.
Wyo.)
Wyo.) 3e. Hunt, Econ. Geol. X: 543, 1915. (Origin and Sicily.)
4. Kemp, Min. Indus., II: 585, 1894.
5. Kerr, Assocn.
(General.)
Eng. Soc. Jour., XXVIII: 90, 1902. (La.) 5a. Larsen and Hunter,
U. S. Geol. Surv., Bull. 530: 363, 1913. (Mineral Co., Colo.) 6. Lee,
U. S. Geol. Surv., Bull. 315: 485, 1907. (Utah.) 6a. Phalen, Econ.
6b. Richards and Bridges, U. S.
(Origin.)
Geol., VII:
732, 1912.
Geol. Surv., Bull. 470: 499, 1911.
7. Richardson, U. S. Geol.
(Ido.)
8. Spurr, U. S. Geol. Surv.,
(Tex.)
Surv., Bull. 260: 589, 1905.
Prof. Pap. 55: 157, 1906.
(Sulphur and alum, Silver Peak, Nev.)
1911.
8a. Stutzer, Die Nicht-Erze,
9. Thomas,
(General.)
Berlin,
Mining World, XXV: 213, 1906. (Texas.) 10. Willey, Eng. and
Min. Jour., LXXXIV: 1107, 1907. (Mining, La.) 11. Woodruff,
Co.,
U.
S.

S. Geol. Surv.,
Woodruff, U.
13.
Min. and
Sci. Press,
Aug.
373,
1909.
Bull.
340:
10. 1907.
12.
(Thermopolis, Wyo.)
1908.
(Cody, Wyo.)
451,
(Colo.)
PYRITE
Properties and Occurrences.
Pyrite, FeS2 when chemically
pure, has 46.6 per cent iron and 53.4 per cent sulphur, and occurs in
well-defined cubes or modifications of the same, in irregular grains
or as granular masses, of a brassy yellow color.
,
It is widely distributed in nature, being found in many kinds of

rocks and in all formations, and in these may occur as disseminated
grains, in contact zones, as concretions in sedimentary rocks, in

and as lenticular bodies of variable size usually in
fissure veins,
metamorphic rocks.
Pyrite as mined is never chemically pure, but contains admixtures of other sulphides, as well as non-metallic minerals.
If chalcopyrite is present in sufficient quantity to bring the
copper content of the ore above 3 or 4 per cent, the material
may be
MINOR MINERALS
401
sold for copper making instead of acid manufacture.

Pyrrhotite is
in some of the Virginia deposits.
In some regions the
abundant
pyrite carries enough gold to render its extraction profitable, but

such deposits are not worked for their sulphur contents.
Pyrite as offered to the trade rarely contains over 43 per cent

sulphur, and if the content falls below 38 per cent, the acid makers
Careful sorting and jigging of the pyrite is usually necesobject.
sary.
able.
Lead, zinc, arsenic, antimony or selenium are objection-
The pyrite produced in the United States is obtained from (1)

Massive deposits, often of lenticular form and disseminations
occurring in gneisses or schists (Va., N. Y.); (2) from the lead
and zinc mines of the Upper Mississippi Valley; and (3) from the
coal mines of Indiana and Illinois.
When pyrite is roasted SO 2 is given off, which is changed to SO 3 by mixing
with fumes given off from a mixture of NaNO 3 and H2 SO 3 in properly conIn thoroughly roasted pyrite there remains a resi"
blue billy" or purple ore, and can be
of iron oxide, which is known as
used in the blast furnace for iron manufacture. The roasted chalcopyrite
structed lead chambers.
due
is
sometimes also used for copper making.

The most important domes-
occurrences are found in a belt of pre-Cambrian metamorphic

rocks extending from New Hampshire to Alabama (8), in which the
tic
Virginia and New York are

pyrite occurs in lenticular deposits.
the most important eastern producers. California is the only
western state producing appreciable quantities.
The counties of Louisa and Prince William

Virginia (7, 8).
contain workable deposits of pyrite, which have been most extensively developed,
tic
and yield a little more than half of the
total
domes-
production.
FIG. 128.
Plan of pyrite lenses at Sulphur Mines, Louisa County, Va., showing

and crystalline schists (6). (After Watson, Min. Res., Va., 1907.)
pyrite (a)
ECONOMIC GEOLOGY
402
FIG. 129.
schists (b)
Min.
Plan of pyrite lens (a), showing stringers of pyrite, interleaved with

on hanging wall. Arminius mine, Louisa County, Va. (After Watson,
Res., Va., 1907.)
In these counties the pyrite occurs as bodies of lenticular shape

(Figs. 128, 129), in quartz-mica schists, which may contain more or
The schists, which

less hornblende and garnet locally developed.
are completely and thickly foliated, have a general strike of N. 10
to 20 E., and a variable dip.
The pyrite is massively granular, and the associated minerals in

the order of their importance are sphalerite, chalcopyrite, galena,
and magnetite. Calcite, quartz, green hornblende, and
red garnet are present, but the last two rather favor the margin of
the ore bodies.
pyrrhotite,
The
lenses of pyrite follow each other along the strike, sometimes

overlapping, and may also be connected by stringers of ore (Fig.
The main bodies may be several hundred feet long, indeed

129).
one in Louisa County has a length of 700 feet and a thickness of 60
to 80 feet.
Another in Prince William County is 1000 feet long.
Pinches and swells are common, and while the pyrite bodies are usuthey may at times grade into the country rock.
ally sharply defined,
An analysis of Louisa County pyrite gave: S, 49.27; Fe, 43.62;

Cu, 1.50; Zn, .38; insol., 4.23; CaO and MgO, 1.32. Traces of
arsenic may be present.
The sulphur averages 43 to 45 per cent.
Watson
considers that the inclosing schists are
undoubtedly
metamorphosed sedimentary limestones, as shown by the presence

of bands and stringers of impure limestones and the abundant development of lime-bearing silicates.
have been formed by replacement.
The
pyrite
is
believed to
The ore is worked by underground methods, the schist picked out,

and the pyrite crushed and jigged. The entire output is used for acid
making. The gossan of the pyrite was originally worked for iron ore.
Sulphuric acid is also obtained from the pyrrhotite-chalcopyrite deposThese are mentioned under Copper.
its of Carroll County, etc.
MINOR MINERALS
403
New York (2, 5a). Pyrite deposits are worked near Canton and Gouverneur, St. Lawrence County. The pyrite is low grade, carrying 20 to 35
per cent sulphur which can be raised to 45 to 50 per cent by concentration.
The ore deposits, which are associated with crystalline limestones and
schists of the Grenville series, appear to represent impregnation zones in
the schist, which by local enrichment may give lens-like accumulations.
Pyrite was produced near Davis, Franklin County .

of irregular width in steeply
The deposits have
dipping, northeasterly striking, crystalline schists.
been opened up along the strike for about 900 feet, and to a depth of 1400
feet on the dip.
Horses of country rock occur in the pyrite. Five feet is
regarded as the minimum workable thickness. Garnets and chalcopyrite
are present, the latter forming either masses or veins in the pyrite. An
analysis of the pyrite concentrates yielded, S, 47 per cent; Fe, 44 per cent;
SiOo, 3 per cent; Cu, 1.5 per cent; Zn, trace; As, none.
Massachusetts
(3, 5).
The material forms a somewhat tabular deposit
Other States.
in
Some pyrite is produced from deposits in crystalline
Clay County, Alabama
California
(1).
product in the mining of coal
Not a
schist
near Acworth and Villa Rica, Georgia, and in

In Indiana, Illinois, and Ohio some is obtained as a by(8),
(6).
pyrite (marcasite) is obtained from the Wisconsin

of
of
a
the
Illinois lead-zinc district.
it is
Some
sepaby-product
little
rating plants, but the greater part

often average 45 per cent sulphur.
is
shipped as mined, and
ANALYSES OF PYRITE AND PYERHOTITE
may
ECONOMIC GEOLOGY
404
According to Fraleck, the pyrite bodies are divisible into 3

(1) Those in gneissoid rocks; (2) those of the iron
formation, including the Helen Mine deposits, where the pyrite
occurs in the hematite; and those of the crystalline limestones of
eastern Ontario; (3) deposits associated with crystalline schists,
classes, viz:
with eruptive greenstones near by.

of lenticular form.
The
ore bodies are frequently
Pyrite of slightly cupriferous character is obtained from Eustis

It is described under Copper.
(la).
and Weedon, Quebec

France, Germany, Italy, Norway, Portugal,
and Spain are all large producers of pyrite, but only the last-named country
serves as an important source of supply for the United States.
The Huelva deposits of Spain, with Rio Tinto as an important producing
town, consist of lenticular ore bodies in schist.
below 47 per cent sulphur.
The
ore
is
said to rarely
fall
Some
Uses
of these are referred to in
more
detail
under Copper (Chapter XVI).
Pyrite is used chiefly and in increasing quanthe manufacture of sulphuric acid. About 75 per cent
of Pyrite.
tities for
of the production is
the rest represents
from pyrite, marcasite and pyrrhotite, while

by-product acid made in connection with
copper and zinc smelting.

This acid is used in the manufacture of superphosphates and
explosives, in refining crude oil, and other ways.
Production of Pyrite.
PRODUCTION OF PYRITE IN THE UNITED STATES, 1910-1911, IN LONG TONS
STATE
MINOR MINERALS
405
PRODUCTION OP PYRITE IN THE UNITED STATES, 1912-1914, IN LONG TONS
STATE
406
ECONOMIC GEOLOGY
Canada. The production of pyrite in 1914 amounted to 224,956

short tons, valued at $735,514, while the exports were 89,999 short
tons, valued at $377,985.
The imports of pyrite in 1914 amounted to 1,026,617

valued
at $4,797,236.
long tons,
They came chiefly from Spain,
from
some
with
Portugal, Canada, and Newfoundland.
Imports.
PRODUCTION OF SULPHURIC ACID FROM COPPER AND ZINC SMELTERS IN

1912-1914, IN SHORT TONS
(Reduced to 60
Baume" acid)
MINOR MINERALS
407
TALC AND SOAPSTONE

Talc, a hydrous magnesium siliProperties and Occurrence.
is
a
cate [H 2 Mg3(Si0 3 )4],
widely distributed mineral, but rarely
occurs in large quantities.

It is characterized by its extreme softness, soapy feel, and freedom
from grit. The color is white, gray, or green; and though generally
foliated, it
may
be fibrous.
a term ordinarily applied to a dark, bluish gray or

Soapstone
greenish rock, composed essentially of talc, but containing other
minerals as impurities, such as mica, chlorite, amphibole (tremois
lite),
and
pyroxene
pyrite.
(enstatite),
It too is soft
and
also quartz, magnetite, pyrrhotite,
enough to be
easily cut with a knife,
and
has a pronounced soapy or greasy feel.

Talc is an alteration product of other magnesia minerals, such as
tremolite, actinolite, pyroxene or enstatite, and is often associated
with talcose or chlorite schists, serpentine, and such basic igneous
rocks as peridotite and pyroxenite.

dolomite.
It is also
found associated with
Soapstone, which often forms large masses, is found chiefly in

In some cases, it has
association with the older crystalline rocks.
no doubt been derived from an altered eruptive rock, but in others
probably from magnesian sediments by metamorphism.

The production of talc
and soapstone is limited almost exclusively to the belt of old crysforming the axis of the Appalachian Mountain system,
and although quarried in eight or ten states, but few are important
producers, and these are mentioned below.
Deposits of talc and soapstone are known in some of the western
states, but commercial conditions have not been favorable for
their development.
Small quantities of talc have been produced
in the past in both California and Washington.
This state is the most important producer of
Virginia (ll).
soapstone, and while the material is found at a number of localities
in the state, nearly the entire production comes from a narrow
northeast belt at least thirty miles long, extending from Nelson
talline rocks
into Albernarle counties.
"
The soapstone occurs
in a
number
veins," 30 to 165 feet in thickness,

of 500 to 800 feet.
The
deposits dip southeast
of dike-like
masses called
and separated by intervals
60, conformable with the
inclosing
ECONOMIC GEOLOGY
408
crystalline schists,
ceous sandstone.
schist, or
which vary from a mica-quartz

Occasionally the wall rock
schist to a mica-
a dark graphite
is
an altered basic eruptive.
The soapstone varies in color from light bluish gray to dark greenish
gray, the former or higher grade containing the most talc, and being the
easiest and most satisfactory to work.
Under the microscope the better grade is seen to consist mostly of talc,
with small quantities of chlorite, magnetite, as well as traces of amphibole
and pyroxene.
The dark green soapstone owes its color and greater
hardness in part to chlorite and other silicates, such as hornblende and
pyroxene. The product is used mainly for laundry tubs, while smaller
amounts are converted into table tops, sinks, and switch boards. Much of
it is shipped to foreign markets.
All of the talc mined in the state is obtained
New York (10).
from a small area southeast of Gouverneur. The most abundant
country rocks of this area are pre-Cambrian gneisses, in which
there occur irregular northeast-southwest belts of crystalline limeThe schistose layers

stone, the greater portion of which is impure.
of impurities carry tremolite and enstatite as their chief constituents, and it is the alteration of these that has produced the talc, the
change being indicated by the following equations
TALC
ENSTATITE
MgSi0 +
3
+ CO 2 =
H Mg3Si
2
12
+ MgC03
TALC
TREMOLITE
*
+ H O + CO2 = H^MgsSiAs + CaCO3

2
This change of the enstatite and tremolite to talc is supposed to

have been accomplished by the action of water charged with CO 2
but whether it occurred at shallow or greater depths is uncertain.
The talc layer, which varies in thickness from a few feet to over 50
feet, averaging about 20, shows either a fibrous or bladed structure.
It is used mainly as a filler for writing papers, being even exported
,
to Europe.
North Carolina (9).
The talc deposits of this state form an interesting
contrast with those of Virginia, for here the material occurs as a series of
lenticular masses and sheets in blue and white Cambrian marbles, thus
In other deindicating its probable derivation from a sedimentary rock.
posits the talc is found in a Cambrian conglomerate, in Archaean rocks
associated with peridotite, showing an undoubted derivation from igneous
rocks.
The
first-mentioned group
is
associated with the
Murphy
Marble, in
MINOR MINERALS
409
Swain County, and forms lenticular bodies, with a maximum size of 50

It crumbles down under weathering
feet thickness and 200 feet length.
Most of the North
action, and the deposits are detected by float material.
Carolina talc is ground to powder, but some is sawed into slabs, or made into
pencils, crayons, gas tips, etc.
Vermont (5). - Talc occurs at a number of localities in Vermont, some

That worked at East Granville is a talc schist, inof which are worked.
That at Chester and Athens occurs in gneiss.
closed between other schists.
New Jersey (8). -Talc has been found at a number of points in the
New Jersey, and also across the river near Easton,

The talc occurs with serpentine in dolomite and near pegmatite intrusions. The latter by contact metamorphism developed tremolite,
white pyroxene, and phlogopite in the limestone. Later, during break-thrust
vicinity of Phillipsburg,
Pennsylvania.
faulting,
accompanying minor
folding, squeezing, and faulting in this area,

by water to talc and other products.
the magnesian silicates were altered
The following analyses from several localities show the kind and
quantity of impurities which good talc may contain:
ANALYSES OF TALC
ECONOMIC GEOLOGY
410
California (3).
counties, California,
Talc deposits which occur in San Bernardino and Inyo

have recently undergone considerable development.
Section of talc deposit near Tecopa, Calif., t, talc with some limestone
and serpentine; b, banded, somewhat cherty limestone, 125
feet; s, lighter colored, less ferruginous, and apparently dolomitic limestone;
(After Diller, U. S. Geol. Sun., Min. Res., 1913.)
d, diorite.
FIG. 130.
tremolite, schist
The
talc
is
usually quite white, and
banded limestone, but
serpentine are found in

in the manufacture of tiles.
Canada
(l, 4)
Talc
is
The
County, Ontario.
lies
on the contact between diorite and

its thickness.
Tremolite and
talc.
It has been used chiefly
very irregular in
association with the
is
mined only in Madoc township, Hastings

material, which is massive and white,
occurs in a brown quartzose limestone of the Grenville series. It

varies from 25 to 40 feet in width, and has been mined for a
There seems to be no
horizontal distance of about 500 feet.
has been formed by the alteration of magnesian

limestone, although the exact process is not clear, except that the
doubt that the
talc
may have yielded silica-bearing

have
been worked intermittently
Soapstone deposits
in southern Quebec (4).
neighboring granite intrusion
solutions.
The largest European talc deposits are

those on the north side of the Pyrenees in southern France. The material
lies
between mica schists and Ordovician
slates,
and contains beds
of lime-
Another important occurrence

stone, as well as scattered granite blocks.
is that found in Styria, where, in a saddle-shaped fold the talc lies between
an underlying graphite slate, and an overlying limestone of Silurian age.

The talc is supposed to have been derived by the alteration of the graphitic
slate and grades into it.
A similar and important occurrence of pure talc
is worked near Pinerolo in northern Italy.
Numerous other foreign deposits
are known, but they are much less important than the above-mentioned
ones.
Uses.
talc.
Talc
is
marketed as rough
sawed slabs, or ground

extreme fineness, softness,
to a number of uses, of which the
talc,
Its peculiar physical character,
and freedom from grit adapt it

following are most important: fireproof paints, foundry facings,
boiler and steam-pipe coverings, soap adulterants, toilet powders,
dynamite, in wall plasters, for dressing skins and leather, as a
MINOR MINERALS
411
base for lubricants, as a filling for paper, and for sizing cotton
cloth.
It has been used to a slight extent for adulterating food.
It can, on account of its softness, be easily sawed or carved, and
extensively used for washtubs, sanitary appliances, laboratory
tanks and tables, electrical switchboards, hearthstones, mantels,
footwarmers, etc. Most of the New York fibrous talc is used as a
paper filler, being better suited for it than the North Carolina
is
product.
pencils,
The compact
and
for coal-
varieties of pure talc are
and acetylene-gas
employed
for
tips.
The average price of rough talc in 1914 for the whole United States was
$5.83 a ton, but some sold as low as $2.00 per ton, and talc worked up into
The average price for manupencils or crayons brought as high as $100.
factured talc in 1914 was $27.98 per ton.
The prices of soapstone vary with the form in which
it is
sold,
and
also
with the size and quality of the stone. In the rough as quarried, its value
ranges from about $1.50 to $2.00 per ton. Sawed slabs of good size and
quality may exceed $15.00 per ton in value, and when manufactured into
laundry tubs, the average value is about $30.00 per ton.
Pyrophyllite differs from talc chemically, being a hydrous alumiinstead of a magnesium silicate, but when sufficiently
num silicate,
free
from
grit, it is
put to the same use as
talc.
It is
sometimes
in-
correctly called agalmatolite, because of its resemblance to the

true mineral of that name. Deposits, more extensive than those
It varies
of talc, are found near Glendon, North Carolina (9).
from green and yellowish white to white, but in all cases becomes
nearly white when dried.
Production of Talc and Soapstone.

has been as follows
last four years
The production
for the
PRODUCTION OF TALC AND SOAPSTONE, 1911-1914, BY STATES, IN

SHORT TONS
ECONOMIC GEOLOGY
412
The total imports of talc in 1914 amounted to 15,734 tons,

valued at $177,321, an increase of 14.4 per cent in quantity and
of nearly 28.8 per cent in value as compared with 1913.
PRODUCTION AND IMPORTS OF CANADIAN TALC
YEAR
MINOR MINERALS
413
The tripoli is an even-textured, finely porous rock, whose grains

are mostly under .01 mm. in diameter, and are probably chalcedony. The following analyses represent the composition of the
stone from Seneca, Missouri:
ANALYSES OF TRIPOLI FROM SENECA, Mo.
ECONOMIC GEOLOGY
414
The rough blocks are sawed up into filter stones, while

Uses.
the spalls and small pieces are ground up for tripoli flour, and there
has been a great increase in the production since 1885. The
worth $6 to S7 per ton f.o.b. Tripoli stone is used to
for blotter blocks and scouring bricks.
Tripoli flour
is used as an abrasive for general polishing, burnishing, and buffing,
ad also as an ingredient of scouring soaps.
tripoli is
some extent
REFERENCES ON TRIPOLI
1.
2. Hovey, Sci.
(Illinois.)
Bain, HI. Geol. Surv., Bull. 4: 185, 1907.
Amer. Suppl., July 28, 1894, p. 15487. (Missouri.) 3. Parr, Ernest
and Williams. Jour. Indus, and Eng. Chera., I: 692, 1909. (Illinois.)
4. Siebenthal and Mesler, U. S. Geol. Surv., Bull. 340:
429, 1908.
(Missouri.)
5.
Glenn, Res. Tenn., IV: No.
1.
(Tenn.)
WAVELLITE
Wavellite has been used to a small extent in the United States as
a substitute for rock phosphate, in making phosphorus.

This mineral does not usually occur in minable quantities, but a
somewhat unique deposit has been found on South Mountain, near
Mount Holly Springs, Pa. There the wavellite occurs in a white

residual clay derived from talcose schists, and associated with manganese and iron ores. The iron and manganese have been concentrated during the weathering of the rocks, and deposited in the
residual materials, near the contact of the limestones of the valley
and the mountain sandstones. The phosphate occurs as nodules,
scattered through a white clay, lying between a manganese-bearing

red clay and the mountain.
The width of the deposit is 40 to 50
feet.
The mining of this material was reported by the United
States Geological Survey for 1906, but since then no production has
been recorded.
used mainly for making matches as well as for fuse

and insect poison, phosphoric acid, and for other
in
used
medicine and the arts. It is also used in the
compounds
Phosphorus
is
compositions, rat
preparation of precious metals, electrotyping,

bronze.
and
in
phosphor
REFERENCES ON WAVELLITE
1.
Stose, U. S.
Geol.
Surv., Bull. 315
325, 1907.
Kept. Pa. State College, 1889-1900, appendix III
2.
:
13.
Hopkins, Ann.
PLATE
XXXVII
1.
Section of an artesian basin. A, porous stratum; B, C, impervious beds
below and above A, acting as confining strata; F, height of water level in porous
bed A, or, in other words, height in reservoir or fountain head; D, E, flowing
wells springing from the porous water-filled bed A.
FIG.
Section illustrating artesian conditions in jointed crystalline rocks without

A, C, flowing wells fed by joints; B, intermediate well between
and C of greater depth, but with no water; D, deep well not encountering
FIG. 2.
surface covering.
pump well adjacent to D, obtaining water at shallow depths; S, dry

hole adjacent to a spring, showing why wells near springs may fail to obtain
water.
joints; E,
3.
Section illustrating conditions of flow from solution passages in limestone.
A, brecciated zone (due to caving roof) serving as confining agent to v/aters
reached by well 1 B, silt deposit filling passage and acting as confining agent to
waters reached by well 2; C, surface debris clogging channel and confining
waters reached by well 3; D, pinching out of solution crevice resulting ia
confinement of waters reached by well 4.
FIG.
Section illustrating conditions of flow from joints, cracks, and solution

passages in stratified rocks covered by impervious clays and fed from morainal
FIG. 4.
drift.
(All after Fuller.)
(415)
CHAPTER
XIII
UNDERGROUND WATERS
THE investigation of underground waters has assumed such importance in the last few years, that it is hardly possible to do it
Howjustice in the limited space which can be devoted to it here.
ever, some of the more salient points can perhaps be touched upon,
and those who desire more detailed information are referred to
the selected bibliography at the end of the topic.
While much of the water used for supplying towns and
cities,
for irrigation purposes, etc., is obtained from below the surface, all
of it originates in rainfall.
The rain water falling on the surface is
disposed of in part by evaporation and surface run-off, but a variable and sometimes large percentage seeps into the ground.
Ground Water
the
(5,
6)
ground
retained
by cap-
illarity
in
the
surface
soil,
to be
returned again to
the atmosphere,
either
by
direct
position of ground water and the undulations of the water

table with reference to the surface of the ground and bed
rock.
through plants;
but most of it
way
Ideal section across a river valley, showing the
FIG. 131.
or
evaporation
finds its
small part of the water soaking into
is
(After Slichter,
U. S. Geol. Sun., Water Supply
Bull. 67.)
into deeper layers of the
soil,
which
it
completely
saturates.
The water
in this saturated zone,
which
is
termed the ground
water (Fig. 131), forms a great reservoir of supply for lakes, springs,
and wells; and its upper surface, known as the water table, agrees
somewhat
it
under
from
and nearer to it under the valleys. Under
may even reach the surface and form springs
closely with that of the land surface, but is farther
hills (Fig. 131),
some depressions
it
The depth of the water

but
few
below the surface in
a
feet
table is quite variable, being
moist climates, while in arid regions it may be 100 feet or more.
or
swampy
conditions (see Fig. 131).
416
UNDERGROUND WATERS
417
In any area, however, the water table may show periodical fluctuaNear
tions, due in part and mainly to variation in the supply.
the coast
In
all
line,
the rise and
fall
ground water there
is
of the tide
may also affect it
(Fig. 132)
a slow but constant movement from
higher to lower levels, just as in the case of surface waters, so that

the ground water flows toward the valleys. There it may dis-
charge into the streams, but in some instances it follows the valley
bottom below the river bed, separated from the river water by a
more or less impervious layer (6). The composition of the ground
water also shows a somewhat close relation to the rocks or soils in
which it accumulates.
Under this heading are included those waters
Artesian Water.
confined in rocks of consolidated or unconsolidated character, under
sufficient
water to
pressure to cause the

toward the surface,
rise
along an avenue of escape, but

not necessarily high enough to
produce an outflow.
The artesian water found in
rocks
may
collect there in cavi-
ties of diverse
FIG. 132.
Section showing effect of tide
on
level of water table.

(After Ellis,
U. S. Geol. Surv., W. S. Bull. 232.)
size,
origin,
and
shape, such as pores between the

gra i ns
joint
Cracks,
bedding
,
,.
...
...
planes, solution cavities, cavities

due to brecciation, gas cavities of lavas, etc. (PL XXXVII). The
surface water finds its way down into these open spaces in the rocks,
and if there is some confining agent, such as denser rock, or other

more or less impermeable barrier, present, it may be held there.
Under these conditions it may be under more or less pressure and if
some avenue of escape, such as a drill hole, is opened up, the water
rises
towards the surface.
The
an artesian flow might therefore be

(1) adequate source of water supply; (2) a
retaining agent offering more resistance to the passage of water than
the well or other opening; (3) an adequate source of pressure.
requisite conditions of
stated as follows (2):
The
retaining agent may be a stratum, vein, or dike wall, joint,

a water layer, etc., while the pressure is due primarily to
variations in level in the different parts of the artesian system,
fault,
although there may be numerous modifying factors. It will be

understood, from what little has been stated above, that a supply of
artesian water might be found under a variety of conditions.
Only
ECONOMIC GEOLOGY
418
two of these will be considered here, although several others are

Shown in Pis. XXXVII and XXXVIII.
The structure sometimes found in stratified
Stratified Beds.
rocks closely approaches the most favorable conditions for an arThat is, we have inclined layers of pervious
tesian circulation.
rock, inclosed between beds of impermeable, or but slightly permeable, character. Water flowing down these permeable beds,
either through the pores, or in the pores and joints together, may
accumulate in sufficient quantity to yield a large and sometimes
steady supply. While sandstones usually show the highest porosity

of any of the sedimentary rocks, limestones may also yield a good
water must accumulate largely in the

Such a structural type, composed of water-bearing
beds between denser ones, may be termed an artesian slope (PI.
flow, although in these the
joint planes.
l),and it is of great importance. The wells tapping

such a supply are sometimes many miles from the area of intake,
and may be sunk to depths of as much as 2000 feet in order to reach
the water-bearing bed. A more or less tight bed over the porous
XXXVII, Fig.
one
but the underlying bed need not be impervious.

of artesian reservoir is that found in
where water-bearing lenses of sand or gravel are over-
is essential,
not
uncommon type
glacial drift
more or less surrounded by clay. In this case the water

downward from the surface collects in the gravel pocket.
lain or
ing
There are
many
seep-
areas in the United States in which the condi-
tions are favorable to
an artesian water supply
in stratified rocks,
as the various state and government reports will show.

the more important ones may be briefly referred to.
few of
Along the Atlantic and Gulf coastal plain an abundant supply

water is obtained from the Cretaceous and Tertiary
beds at depths varying from 50 feet along the inland border, to
1000 feet and over along the coast (7, 10, 22, 41, 48) (Fig. 133).
of artesian
A second area is that of the upper Mississippi Valley (50), in

which an abundant supply of potable water is obtained from the
St. Croix and St. Peters sandstone, whose outcrop in Minnesota
and Wisconsin covers some 14,000 square miles.
In the Great Plains (8) region water is obtained from the Dakota
sandstone, whose collecting area is around the border of the Black
This
Hills (Fig. 134) and eastern edge of the Rocky Mountains.
source is available in South Dakota and eastern Nebraska and
Kansas and Colorado. The chief use of the water in this region
is
for irrigation.
FIG.
1.
FIG.
2.
Fie.
3.
Section illustrating conditions of flow from foliation and schistosity planes.

A, Foliation plane feeding flowing well 1. (After Fuller.)
Section illustrating conditions of flow from vesicular trap.

zone feeding well 1. (After Fuller.)
A, Vesicular
Section showing accumulation of water in stratified rocks with low intake.

(After Ellis.)
(419)
ECONOMIC GEOLOGY
420
For the arid regions of the west this source of supply has been of
inestimable value, and has been the means of reclaiming many an
area of hitherto useless land.
FIG. 133.
Geologic section of Atlantic Coastal Plain, showing water-bearing hori(After Darton, Amer. Inst. Min. Engrs., Trans. XXIV.)
zons.
Crystalline Rocks.
considerable
tical joint
amount
Recent investigations have shown that a

of water
may
seep
planes of crystalline rocks (PI.
granite, crystalline limestone, gneiss,

in the horizontal joint fissures, but
rocks, very
little
and
downward along the
XXXVII, Fig.
schist,
2),
ver-
such as
and become stored
owing to the density of these

water can accumulate in the pores. If now a well
GRANITE |/_-/-~X*
FIG. 134.
Section from Black Hills across South Dakota, showing artesian well
conditions.
(After Darton.)
so as to strike these water-bearing joints, a more or less

steady supply may be obtained. In most cases the volume is not
more than 10 gallons per minute, but occasionally as much as 90
is drilled
gallons has been obtained by pumping.

While the finding of a supply of water in crystalline rocks
is
more
UNDERGROUND WATERS
421
still the proportion of successful wells is

although the possibility of success decreases greatly below
200 feet, and is less even below 50 feet than above it.
A number of wells have been bored in the crystalline rocks of
or less a matter of chance,

large,
New
England and even other eastern states
(3, 21,
31).
REFERENCES ON UNDERGROUND WATERS

1. Chamberlin, U. S. Geol. Surv., 5th Ann.
2. Fuller, U. S. Geol.
(Artesian water supply.)
3.
(Controlling factors of Artesian flow.)
Surv., BuU. 319, 1908.
525, 1909.
(Water in crystalline rocks.) 4.
Clapp, Eng. Rec.,
Johnson, U. S. Geol. Surv., W. S. pap. 122, 1905. (Relation of law to
underground water.) 5. King, U. S. Geol. Surv., 19th Ann. Rept., II :
ORIGIN AND ACCUMULATION.

Rept.
125, 1885.
LX
1899.
(Underground water circulation.) 6. Schlichter, U. S.
Geol Surv., W. S. pap. 67, 1902. (General on underground waters.)
AREAL. General: 7. Darton, U. S. Geol. Surv., Bull. 138, 1896. (At8. Darton, U. S. Geol. Surv., Prof. Pap. 32,
lantic Coastal Plain.)
1905. (Central Great Plains.) 9. Darton, U. S. Geol. Surv., W. S. pap.
149, 1903.
(Deep well borings of U. S.) See also Fuller and others,
No. 264, 1905. 10. Fuller and others, U. S. Geol. Surv., W. S. pap,
114,1905. (E.U. S.) 11. Fuller, Ibid., No. 100, 1905. (Hydrography
U. S.) 12. Fuller and others, U. S. Geol. Surv., W. S. paps. 120, 1905.
Alabama
13. Smith, Ala. Geol.
and 163, 1906. (Bibliography.)
Arkansas
14. Veatch, La. Geol. Surv., Bull. I.
Surv., Bull., 1907.
California: 15. Lee, U. S. Geol. Surv., W. S. pap.
1905.
(S. Ark.)
59,
181, 1906.
(Owens Valley, Calif.) 16. Mendenhall, Ibid., No. 225.
17. Mendenhall, Ibid., No. 222, 1908.
1909.
(San
(Indio region.)
Joaquin Valley.) 18. Mendenhall, Ibid., No. 219, 1908. (Calif.)

18a. Waring, Ibid., No. 338, 1915.
Colorado:
(California Springs.)
19. Eldridge, U. S. Geol. Surv., Mon. 27.
(Denver basin.) 20. Gil20a.
(Ark. valley.)
bert, Ibid., 17th Ann. Rept., II:
557, 1896.
ConDarton, U. S. Geol. Surv., Prof. Pap. 52, 1906. (Ark. Valley.)
necticut: 21. Gregory, U. S. Geol. Surv., W. S. Pap. 232, 1909.Florida:
21a. Sellards, Fla. Geol. Surv., Bull.
and Matson and Sanford, W.
S.
Paper, 319,
McCallie, Ga. Geol. Surv., Bull.
7,
1899,
1,
1908.
1913.
(Cent, Fla.)
Georgia:
and Stephenson, et
Illinois:
23. Udden,
al.,
W.
22.
S.
111.
Geol.
(Coastal Plain.)
341, 1915.
(Peoria district.) 24. Savage, Ibid., Bull.
Surv., Bull 8: 313, 1907.
4: 235, 1907.
25. Leverett, U. S. Geol.
(Springfield quadrangle.)
Pap.,
Indiana: 26. Leverett, U.

Surv., 17th Ann. Rept., II: 701, 1896.
S. Geol. Surv., W. S. Pap. Nos. 21 and 26, also Capps and Dole, W. S.
Pap. 254, 1910.
XXI,
1912.
Iowa: 27. Norton, la. Geol. Surv.,

(N. cent. Ind.)
27a. Haworth, W. S. Pap. 6, 1897.
Ken-
Kansas:
Matson, U.
S. Geol. Surv., W. S. Pap. 233, 1909.

(Blue
Also Glenn, W. S. Pap. 164, 1906.
Louisiana: 29.
30. Harris, U. S.
Harris, and Veatch La. Geol. Surv., Bull. I, 1905.
Geol. Surv., W. S. Pap. 101, 1904.
Maine: 31. Clapp and
(S. La.)
Michigan: 32.
Bayley, U. S. Geol. Surv., W. S. Pap. 223, 1909.
tucky:
28.
grass region).
ECONOMIC GEOLOGY
422
W.
W.
W.
W. S. Paps. 30 and 31. 33. Leverett, Ibid.,

Mississippi: 34. Crider and Johnson, U. S. Geol. Surv.,
Missouri: 35. Shepard, U. S. Geol. Surv.,
S. Pap. 159, 1907.
Montana: 36. Fisher, U. S. Geol. Surv.,
S. Pap. 195, 1907.
Nebraska: 37. Condra,
S. Pap., 221, 1909.
(Great Falls Region.)
U.
S. Geol. Surv.,
Lane, U. S. Geol. Surv.,

183, 1907.
New
8.
W.
S.
Pap. 215, 1908. (N. E. Neb.). See also Ref.

U. S. Geol. Surv., W. S. Pap. 145,
38. Smith,
Hampshire:
New Jersey: 39. Woolman, N. J.

J905.
(Portsmouth, region)
New
Geol. Surv., Ann. Rept., 1902: 59, 1903. See also Ref. 7.
Mexico: 40. Lee, U. S. Geol. Surv., W. S. Pap. 188, 1907. (Rio
New York: 41. Veatch and others, U. S. Geol.
Grande valley.)
Surv., Prof. Pap.
44,
1905.
(Long Island.)
Ohio:
41a. Fuller
and
Oklahoma: 42. Gould,

(S. W. Ohio.)
Pap. 259, 1912.
U. S. Geol. Surv., W-. S. Pap. 148, 1905.
Oregon: 43. Waring, U.
Texas: 44.
S. Geol. Surv., W. S. Pap. 220, 1908.
(S. Cent. Ore.)
(Panhandle region.)
Gould, U. S. Geol. Surv., W. S. Pap. 191, 1907.
Clapp,
W.
S.
45. Taylor, Ibid., No. 190, 1907, and Deussen, Ibid., 335, 1914.
(S.
Utah: 46. Lee, U. S. Geol. Surv., W. S.
E. Tex.)
(Coastal plain.)
Pap. 217, 1908. (Beaver Valley.). 47. Richardson, Ibid., No. 157,
1906.
Virginia: 48. Watson, Min.
(Utah Lake and Jordan River.)
Res. Va.: 259, 1907, and Sanford, Va. Geol. Surv., Bull. IV, 1913.
-Washington:
consin:
51.
49.
Ruddy, Wash. Geol.
50. Kirchoffer,
Bull. Univ. Wis.,
Surv., I:
296, 1901.
No. 100, 1905.
Wis-
(General.)
Weidman, Wis. Geol. Surv., Bull. 16: 666, 1907. (Crystallines

N. Cent. Wis.)
Wyoming: 52. Knight, Wyo. Univ. Exper.
area,
Sta., Bull. 45, 1900.
MINERAL WATERS
This term is commonly applied to those spring waters containing
a variable amount of dissolved solid matter of such character as
Their origin, although often
to make them of medicinal value.
dissolved
substances having been
is
the
as
curious,
simple,
regarded
derived from the rocks through which the spring waters have circuMany mineral waters contain carbonic and even other acids,
lated.
which further increase their powers of solution. There

apparently some connection between hot mineral springs and
geological structure, as they are more abundant in regions of faulting or recent volcanic activity. Waters flowing from shallow
sources usually show the lowest mineralization, and those derived
from sedimentary rocks often show a greater quantity of dissolved
material than those occurring in igneous rocks.
Springs whose temperature is above 70 F.' are termed thermal,
those between 70 F. and 98 F. being classed as tepid, and those
and
is
alkalies,
UNDERGROUND WATERS
423
hotter than this as hot springs.

The following will serve as examples to show the temperature of different thermal springs Sweet
:
Springs,
West
Virginia,
74
F.;
Warm
Springs,
French Broad
River, Tennessee, 95; Washita, Arkansas, 140 to 156; San

Bernardino Hot Springs, California, 108 to 172; Las Vegas, New
Mexico, 110 to 140.
The volume of discharge shown by mineral springs is quite variable.
The famous Orange Spring
of Florida discharges 5,055,000
gallons per hour, while others are as follows:
Champion
Springs,
New
York, 2500 gallons; Roanoke Red Sulphur Springs,

1278
Virginia,
gallons; Warm Sulphur Springs, Bath, Virginia,
360,000 gallons; Glen Springs, Waukesha, Wisconsin, 45,000
Saratoga,
gallons.
waters may be geographic, geoor

that
logic, therapeutic,
prepared by A. C. Peale is
chemical,
as
mineral waters into
as
He
subdivides
perhaps
satisfactory
any.
While a
classification of mineral
the following classes
Alkaline
ECONOMIC GEOLOGY
424
are those of sodium or magnesium, since they have similar medicinal effects.
The engineer must know which, as the former is harmless, while the latter
forms boiler
scale.
There
Distribution of Mineral Waters in the United States.
according to Peale, between eight and ten thousand mineral

springs in the United States, and of this number 695 reported production, 1908. The majority of the commercially valuable mineral
are,
springs are located in the eastern United States and Mississippi

West of the 101st meridian they are confined chiefly to
Valley.
the Pacific coast.
No
thermal springs are
known
in
the
New
the American springs, those at Saratoga,

New York, have an international reputation, and compare well
with many of the foreign ones. Others of importance are the Hot
England
states.
Among
Springs of Virginia and the Hot Springs of Arkansas.

The following table contains the analyses of several types of
mineral waters from the United States
:
ANALYSES OF AMERICAN MINERAL WATERS
UNDERGROUND WATERS
425
PRODUCTION OF MINERAL WATER IN THE UNITED STATES, 1910-1914

YEAR
PART
II
ORE DEPOSITS
CHAPTER XIV
ORE DEPOSITS
Definition.
The term ore deposits is applied to concentrations
of economically valuable metalliferous minerals found in the earth's
crust, while under the term ore are included those portions of the
ore deposit of which the metallic minerals form a sufficiently large

proportion and are in the proper combination to make their extraction possible and profitable.
The term ore mineral can be applied
to those minerals carrying the desired metallic elements which
occur within the deposit. These ore minerals

the entire mass of the ore.
may
in
some cases
make up
A metalliferous
mineral or rock might therefore not be an ore at

become so at a later date, because improved
the present day, but
methods
of treatment or other conditions rendered the extraction
of its metallic contents profitable.

few metallic minerals serving as ore minerals, such as gold,
copper, platinum, and mercury, sometimes occur in a native condi-
tion
but in most cases the metal
is
combined with other elements,
forming sulphides, oxides, carbonates, sulphates, silicates, chlorides, phosphates, or rarer compounds, the first five of these
being the most numerous. A deposit may contain the ore minerals
of one or several metals, and there may also be several compounds
same metal present.

Associated with the economically valuable
Gangue Minerals.
of the
metallic minerals there are usually certain common ones, of metallic

or non-metallic character, which carry no values worth extracting.
These are termed the gangue minerals. They often form masses
in the ore deposit which can be avoided or thrown out in mining,
but at other times they are so intermixed with the valuable metalliferous minerals that the ore is crushed and the two separated
by
special methods.
Quartz
fluorite,
is
and
the most abundant gangue mineral, but calcite, barite,

siderite are also common, while dolomite, hornblende,
pyroxene, feldspar, rhodochrosite,
etc.,
429
are found in
some ore
bodies.
ECONOMIC GEOLOGY
430
The fact that ores form masses of greater

Origin of Ore Bodies.
or less concentration is explainable in two ways
either they have
been formed at the same time as the inclosing rock (contemporaneous or syngenetic) or else they have been formed by a process of
:
concentration at a later date (subsequent or epigenetic). The first

theory is found to be applicable to some ores in igneous rocks,
and to some sedimentary ones, while the second applies to most
ere deposits, regardless of the character of the inclosing rock.
It must not be inferred from this, however, that the origin of all
known ore bodies has been definitely settled, for a strong difference
sometimes exists among geologists regarding the same

first in one class and then in
deposit,
but
with
all
this
shifting the number of occurrences
another;
in
the
class
has increased considerably and now
falling
syngenetic
includes some large and important ore deposits.
These may be divided into two groups,
Syngenetic Deposits.
of opinion
and some have been placed
viz.
those of magmatic origin, and those of sedimentary origin.
Magmatic Segregations
(2, 4, 13, 21,
52-60).
Under
this head-
ing is included a small class of deposits, whose intimate association with igneous rocks proves beyond doubt that they have been
derived from the igneous magma by a process of segregation during their crystallization from
it.
These separations generally take place during the early stages

of cooling, and form the first of a series of minerals, usually crystalizing out in a
somewhat
definite order.
The order of crystallization stated by Rosenbusch, and which applies

especially to granitic and dioritic rocks, there being some exceptions for more
basic ones, is as follows:
1.
Iron
ores aiid accessory constituents (magnetite, hematite, ilmenite,
apatite, zircon, spinel, titanite, etc.).

2.
3.
silicates (olivine, pyroxene, amphibole, mica, etc.).

Feldspathic constituents (feldspars and feldspathoids, including leucite,
Ferromagnesian
nephelite, sodalite, etc.).

4.
Free
We
silica (quartz).
see then that the crystallizations
show an order
of decreasing basicity.
Moreover, if the magma contains watei, this is retained in part in the still
fluid or molten part, so that finally we may have a mixture of silica, possibly
some alkalies, water and other mineralizers (fluorine, boron, etc.).
Separations of the heavy metals appear to be characteristic

magmas deficient in acid-forming constituents, but this
not surprising, for a consideration of the composition of igneous
of igneous
is
ORE DEPOSITS
431
v^
rocks shows us that sincere basicity of an eruptive rock depends
partly on the percentage of the oxides of heavy metals, the basic
ones are more apt to yield ijiagmatic separations than the acid ones.
In some cases, however, metallic concentrations occur in acid
rocks.
In these segregations
it is
seen that the metallic minerals which
have gathered together to form the ore deposits are simply common
accessory, and not important, constituents of the igneous rocks.
That
erals,
body and the country rock contain the same minbut the relative abundance of the silicates and metallic
is,
the ore
^*SM^.
R3&Z*&f3S&*
u VlJfi
FIG. 135.
Chromite
in olivine (in part altered
Austria.
minerals
is
reversed.
chromium
to serpentine),
from Kraubath,
X 15.
As an example: the average percentage
in the rocks of the earth's crust is
about .01 per cent.

In a peridotite magma it forms about .2 per cent, but in segregations within the magma we find 40 to 60 per cent CÔs.
of
Where the
metallic minerals
crystallize
out and segregate,
the ore body forms a portion of the igneous mass, and usually
grades off into it, but in some cases the ore minerals have not only
become
differentiated from the parent magma, but this separated

portion has been forced up from below, independent of the rest
of the igneous mass, thus forming a true dike.
The end products in the cooling of a magma, which crystallize

out as pegmatite dikes or quartz veins, may sometimes carry
metals, such as tin (North Carolina) or gold (Silver Peak, Nev.)
ECONOMIC GEOLOGY
432
and these are
likewise regarded
by some
as
magmatic syngenetic
deposits.
Ores formed by magmatic segregation show a crystalline text(Fig. 164), usually of coarse, but sometimes fine, grain.
ure
Porphyritic texture is sometimes developed in these deposits,

the phenocrysts being ore minerals.
Graphic inter-growths may
occur, and while some believe it indicates that the magma contained a eutectic mixture of two minerals which crystallized at
the same time, this view is not held by all geologists.
Form
Ore deposits formed by

of Magmatic Ore Bodies.
magmatic segregation not only show a varying degree of conSome
centration, but vary greatly in their size and form.
exhibit vast dimensions, as the Scandinavian iron ore deposits
and Luossavara (Fig. 162); indeed, [these are
of Kirunavara
much
larger than any of this type known in North America,

the nearest approach to them being the nickel deposits of Sudbury-Ontario.
(1) as irreguMagmatically segregated ore bodies may occur
:
larly distributed deposits, which show a transition into the surrounding igneous rock; (2) as deposits on the border of the igne-
ous rock, but lying mainly within the former and sending tongues
out into either; or (3) as dikes in the igneous rock. In the latter
case they might be regarded as very basic segregations, which have
been forced up from below, subsequent to the intrusion of the basic

itself.
(See Iron ore, Wyoming.)
As stated above, the number of ore deposits formed by magmatic
rock
is
segregation
be referred to
1.
small in number, but the following types can probably

this class
Titaniferous iron ores in basic and intermediate eruptives
New York, Iron Mountain, Wyoming, etc.), and

perhaps some iron ores in acid eruptives (Mineville, New York).
2. Chromite in peridotites and the secondary serpentines.
3. Some sulphide ores (Sudbury, Ontario, and Lancaster, Penn-
(Adirondacks,
4.
sylvania) (?).
Nickel-iron ores in eruptive rocks (no value).
6.
Platinum in basic eruptives (no value).

Tin ores in some pegmatites (South Carolina).
7.
Some
5.
1
gold ores in quartz veins (Silver Peak, Nevada).
Syngenetic Deposits cf Sedimentary Origin.
mentary rocks are

1
of
If ores in sedi-
contemporaneous origin they must have been
These would be referred to the deeper vein zone by some.
ORE DEPOSITS
433
formed at the same time as the rock in which they occur, the
process being either a chemical or mechanical one, similar to that
by which the different kinds of stratified rocks have been formed.
Two classes might be recognized, viz. (1) interstratified deposits,
and (2) surficial deposits or placers.
These may have originated
Interstratified sedimentary deposits.
by processes analogous to those which have formed the inclosing
rocks.
Some may have accumulated by precipitation from sea
water or fresh water, a process which is going on even at the present
day, as shown by the deposition of limonite in ponds, or the formation of nodules of limonite, pyrite, or manganese on the ocean bottom.
Others may be of mechanical origin, the grains of metallic

minerals having been set free by disintegration of rocks on the land,
and the particles later becoming segregated, as in the case of magne-
may
formed along the beaches by wave action. Both types

be subsequently covered up by other sediments, or in rarer
cases
by igneous
tite sands,
flows.
Sedimentary deposits of the two types just mentioned are of

tabular form, and thin out horizontally in all directions, but many
of them are of great extent and even of curiously uniform character, as for example the Clinton ores of the eastern United States
(p. 538), the bedded limonites of France and Germany (p. 556)
or the hematite of Newfoundland (p. 546). They are sometimes
sharply separated from the inclosing rocks, or at others grade into
them. Further characteristics to be noted are the absence of
fragments of the overlying country rock in the ore and of veinlets
branching off from the bed. If folding of the rocks has occurred,
the beds follow the folds. Sedimentary deposits are occasionally
enriched by water circulating through the beds and causing a
concentration of the contents, either by removal of soluble ele-
ments, addition of metallic compounds or rearrangement of those

present.
Syngenetic bedded deposits often show a fine-grained
In cases they are oolitic or even fossiliferous, the metaltexture.
lic
minerals in part replacing the
crystalline quartz
Placer
deposits.
fossils.
Some may show
finely
and
also finely crystalline secondary minerals.

This term is applied to deposits of gravel,
sand, or even clay, containing heavy metallic minerals like gold,

cassiterite, platinum, etc,, concentrated usually by mechanical
agents such as streams, waves or wind.
When the products of rock decay are washed down the slopes
434
ECONOMIC GEOLOGY
and into the streams, the
lighter material is carried off to sea, while

the heavier particles such as pebbles and metallic mineral grains
remain behind in the stream channels. The metallic fragments
by reason of their higher specific gravity settle to the bottom of

the channel, and all become more or less rounded by the rubbing
action they are subjected to while being moved along by the stream
current.
Placer deposits
may
also be
formed along beaches by wave
action, while a rare type are those which originate in dry climates
by the disintegration of rock, little of the material being removed,
except sandy particles which are blown
away by the wind.
somewhat
special type, called eluvial placers, originates by the

weathering of gold-bearing rocks, the residual products remaining
at the point of origin, or migrating a short distance down grade.

The gold in these is rough and angular. Eluvial placers are known
in the southern Appalachians.
From what has been said above, one must not get the idea
that placer deposits did not form in the past, for they did, and are
known to exist in sedimentary formations as far back as the
(See Gold, South Dakota.)
These, as previously stated, are of
Epigenetic Ore Deposits.
In other words, they have been
later age than the inclosing rock.
Cambrian.
concentrated in the rocks by natural processes.

In order to demonstrate this it is necessary to show: (1) the
source of the metals found in the rocks; (2) the existence of a car-
which could transport the metals, in solution probably; and (3)

the existence of conditions favorable to the precipitation of the ore.
rier
Occurrence of Metals in the Rocks.
It is well
known
that
metallic minerals in small quantities are widely distributed, in both

igneous and sedimentary rocks. Sandberger (18), for example,
has shown by analyses the presence of nickel, copper, lead, tin,

and cobalt in such minerals as hornblende, olivine, and mica; and
Curtis has found traces of silver, gold, and lead in the quartz-por1
phyries at Eureka, Nevada, and silver, arsenic, lead, copper,
and gold in the granite at Steamboat Springs, Nevada. 2 Grout 3
found .029 per cent copper in Keweenawan traps of Minnesota,

while Lewis4 recorded .025 per cent CuO in the New Jersey dia1
2
U.
S. Geol. Surv.,
Ibid.,
Mon. XIII:
Mon. VII:
350.
Econ. Geol., V: 471, 1910.
lbid., II:
242, 1907.
80.
ORE DEPOSITS
435
Winslow has pointed out the presence of small quantities

and zinc in the limestones of Missouri and Wisconsin (see
lead and zinc references), and Wagoner has made similar tests on
base.
of lead
California sediments (172).

originally derived
latter
must be the
rocks.
Since, however, the sediments were

it follows that the
from the igneous rocks,
1
original source of the minerals.
It is interesting
to note that even in the igneous rocks the metals are not impartially distributed, but that certain metals seem to favor certain
Thus
iron,
manganese, nickel, cobalt, chromium, and
platinum, seem to favor basic rocks; while tin, tungsten, and some
Titanium has been found in
rarer metals favor the acid ones.
both acid and basic.
While the occurrence of metallic minerals
in the rocks of the
earth's crust is widely recognized, few, perhaps, realize the small

percentage existing outside of those concentrated portions, the
ore deposits; and the following table, showing the average com3
position of rocks of the earth's crust, will serve to emphasize
this point:
Oxygen
Silicon
Aluminum
Iron
Calcium
Magnesium
Potassium
Sodium
Titanium
47.29
28.02
7.96
4.56
3.47
2.29
2.47
2.50
46
078
Manganese
Sulphur
103
Barium
092
033
020
004
063
Chromium
Nickel
Lithium
Chlorine
Fluorine
10
Zirconium
Hydrogen
Carbon
.16
Vanadium
13
Stiontium
Phosphorus
.13
017
017
033
An examination of the above figures shows that, of some twenty

metals that are of importance to us for daily use, only five, viz.
aluminum, iron, manganese, chromium, and nickel, are included
above list, and that the others must be present in amounts
of less than .01 per cent.
Professor Vogt 4 has endeavored to estimate the approximate
in the
average amount present of other important (economically) metals,

1
For a most interesting discussion
Bull. 606:
2
of this see Siebenthal,
67, 1915.
De Launay, Ann.
d. Min., Aug., 1897.

Clarke, U. S. Geol. Surv., Bull. 616: 27, 1916.
Zeitschr. prak. Geol., July and Sept., 1898.
U.
S. Geol. Surv.,
ECONOMIC GEOLOGY
436
not included in the table on page 435.

percentage amount
of tin, zinc,
and lead
According to him, the

is expressed by a digit
in the third or fourth decimal place, copper in fourth or fifth,

silver in sixth or seventh, gold and platinum in seventh or eighth.
Mercury would show a slightly larger percentage than silver, and

antimony, molybdenum, and tungsten, between copper
and silver. Bismuth, selenium, and tellurium would be placed
between silver and gold in the list.
Lindgren (13) differs somewhat from Vogt, and would place the
percentage of copper at .01 to .005, zinc at .004 per cent and lead
arsenic,
at .002 per cent.

He suggests that silver may constitute .00001
per cent of the earth's crust, and gold .0000005 per cent.
As
actual examples of the
following determinations
localities:
METAL
amounts
made on
present,
we may quote
the
eruptive rocks from several
ORE DEPOSITS
lead
may
facilitate
437
the extraction of gold and
silver,
while zinc
Lastly, with changed conditions, a rock which was

formerly of no economic value may become a profitable ore to
work, partly because improved methods of treatment have
hinders
it.
lowered the cost of production.
an ore
in
Ores
"
for profitable
working
The quantity
is
of metal necessary
"
Value of
referred to under
in this chapter.
Source of Water in the Earth's Crust (142, 143, 145, 147, 152). is known to be widely but not uniformly distributed in
the rocks of the earth's crust, and much of it is in slow but con-
Water
Geologists admit that this ground water has

carrier, but there has existed a strong
stant circulation.
been an important ore
difference of opinion, regarding its source, or at least the source

of that portion which has been active as an ore carrier.
Three types of ground water are recognized,

Connate and (3) Juvenile.
viz.
(1)
Meteoric,
(2)
Meteoric Water.
variable portion of the rain falling on the

and other cavities of the
earth's surface penetrates the pores
regolith and bed rock, forming a more or less saturated zone,

whose upper limit is known as the water-table. While the latter
follows in a general way the surface contours, it may approach
close to the surface under the valleys, and lie at a greater depth
In moist regions the average depth of the water

hills.
shallow, but in arid regions it may lie deep, sometimes
2000 feet or more.
below the
table
is
Between the surface and the water table
is
a zone of descending
oxidizing waters, as well as one containing altered rocks and

This zone has been variously called the vadose region
minerals.
(Posepny),
belt
of weathering
(Van Hise) and gathering zone
(Finch).
Below the water table, the meteoric water penetrates to

variable but probably not great depths.
Some, like Van Hise,
believed that it might go as deep as cavities existed, in other
words to the bottom of the zone of fracture or cavities. Hoskins figured that this might be as deep as 10,000 meters, but the
l
experiments of Adams and King indicated that it may be even
deeper.
The last named, in their experiments, subjected granite cylinders with a

.05-inch hole bored through them to a pressure of 96,000 pounds per square
inch, and a temperature of 550 C.for 70 hours, without producing any change
1
Jour. Geol.,
XX:
119, 1912.
ECONOMIC GEOLOGY
438
The pressure corresponded to that which would exist at a

depth of 15 miles, and the temperature to that estimated to prevail at 11 miles
below the surface. In granitic rocks therefore cavities might exist at the
above mentioned depth.
in the opening.
There seems strong doubt, however, as to whether surface

waters penetrate to any such depth, for observations in mines not
only indicate frequently a decrease in water with depth, but the
bottoms of some deep ones are dry and dusty.
Finch suggests dividing the water below the water table into
two zones. The upper one he calls the discharge zone, and in this
the water is in lateral motion toward some lower discharge level.
The lower is called the static zone, and in this the water is stationary or nearly
so.
Attempts have been made to estimate the quantity of water in the outer
part of the earth's crust, the amount being expressed in terms of thickness of
a sheet of water covering the earth's surface. 1
These estimates by
different authors are:
Delesse, 1861, 7500 feet.

Slichter, 1902, 3000-3500 feet.
Chamberlin and Salisbuiy, 1903, 800 feat.
Chamberlin and Salisbury, 1903, 1600 feet (on another assumption).
Van Hise, 1904, 226 feet.
Fuller, 1906, 96 feet.
The
later estimates,
which are probably more exact, indicate a rather
shallow depth, and indicate the impossibility of assuming meteoric waters

to be genetic factors in the formation of deep veins.
That meteoric waters were the most important, if not the only
was advocated by many of the earlier
2
3
4
geologists, including J. Le Conte, F. Posepny, and L. De Launay,
collecting agents of ores,
while in recent years this theory of ore formations has been strongly
urged by Van Hise (12).

There is no doubt that the circulation of meteoric waters
quite extensive,
and
it
is
plays an important role in the secondary
concentration of ores, by downward-moving solutions, but its

effects as a factor in the primary concentration of ore deposits
are probably unimportant except in a few regions.
Connate Water
rocks containing
1
2
3
Fuller,
This is water which is indigenous to the

such as original sea-water in a sedimentary
(147).
it,
Water Supply Paper,
160: 59, 1906.
Amer. Jour. Sci., July, 1883, p. 1.

Trans. Amer. Inst. Min. Engrs., XXIII,
La Recherche, Captage,
et
p. 213.
Amenagement des Sources Thenno-Minerales.
PLATE
XXXIX
FIG.
Specimen from Moresnet, Belgium, showing

Dark bands, pyrite (M)
(From specimen in Cornell collection.)
FIG.
crustified structure.
1.
bands, sphalerite (S)
Light grains, galena
Light
((?)
2.
Steamboat Springs, Nev. The white deposit is siliceous sinter carrying
mercury and antimony. Steam rises from numerous fissures whose sides are
coated with sulphur crystals.
(H
Ries, photo.)
(439)
ECONOMIC GEOLOGY
440
rock or magmatic water in an igneous rock. In the former it is

found chiefly in sandstones and sands, the brines of the Lower
Carboniferous and some other formations being examples of it.
Igneous rocks may retain some of their magmatic waters on
consolidation,
which go on
and it is possible that some of the changes

them after solidification depend on this residual
in
liquid (13).
Submarine lava flows may absorb ocean water, and that found
some deeply-buried lava flows, as those of the Keweenaw penLane (l 8), in his
insula of Michigan, may be of this nature.
Lake Superior work, has called attention to the relatively large
in
calcium chloride content of the copper-mine waters at depths of

600 to 1600 feet, and believes that it must be of marine origin.
In fact, both sodium and calcium chlorides are in evidence with
depth, the former preponderating at first, but deeper down yielding to the latter.
Magmatic Water
(40,
75,
80,
83,
130,
145,
147,
152).
The
majority of geologists now believe that the primary concentration of ores has in most cases been performed by magmatic waters.
This theory, although it has grown greatly in recent years,

not a new one, for it was suggested by Elie de Beaumont as
1
but its full significance was not grasped until
early as 1850;
is
some years later, when the writings of Vogt 2 (in 1894), Spurr,3
Lindgren, and especially Kemp (80) did much to emphasize its
importance.
The
general theory is that deep-seated masses of igneous rock

have dissociated water as well as other gaseous elements, the
water-
and
addition,
the
gas-filled
there
magma
may
solidified,
In
in quartz indicating this.
As
water.
combined
be
also
chemically
the water (probably in gaseous form) was
cavities
expelled, carrying along dissolved substances.

Some have claimed, of course, that the water contained within
magma may have come from external sources in

ways as follows: 1. By infiltration of sea-water to
the
at least
two
the igneous
drive it
would
heat
as
the
a
somewhat
mass,
unlikely process,
2. By the absorption of hydrated rocks, which became
out.
engulfed in the rising
magma
phenomenon regarding which

1
2
8
as
field
it
forced
evidence
its
is
lacking.
Geol. Soc. France, Bull. IV: 1249.

Zeitschr. fiir prak. Geol. II.
U.
S. Geol. Surv.,
way upward, a
16th Ann. Kept., II.
ORE DEPOSITS
441
One thing seems certain, and that is, that the igneous rocks
give off water in vaporous form during cooling. Evidence of
its presence is found in volcanic emanations, as most convincingly
shown by Day
by
against
and the work
this evidence there is
of R. T. Chamberlin. 1
field
data, that water
is
not given
of the points brought out
by the advocates
of
magmatic
based on possibly insufficient

off
by the analyses published

As
the statement of P. Brun (37),
and' Shepherd (39),
F. C. Lincoln (40),
by magmas.
Many
waters as ore-concentrating agents have been used as arguments

These include
against the possible efficiency of meteoric ones.
the following: Meteoric waters do not reach great depths, in fact
probably not more than 2000 feet or sometimes less from the
surface, and when they do penetrate to a greater distance, it is
because they have followed some fissure. The lower levels of
many deep mines are so dry as to be dusty. Ores have been concentrated at a much greater depth than that reached by surface
waters.
It is
perfectly reasonable to regard igneous rocks as
an important source of water, and the experiments of Daubree

have shown that a molten granite contains a large amount of
vapor which it retains while at great depths, but gives off on
approaching the surface and cooling.
It is an undeniable fact that most metalliferous veins are found
in areas of igneous rocks, and Lindgren (see Metallogenetic Epochs
on a later page) has shown that in the case of the gold deposits
of North America the periods of vein formation agreed closely
with those of igneous activity. It is also a noteworthy fact that,
with the exception of some deposits of commoner metals, such as
some iron, copper, lead, and zinc, ores are found in close association with igneous intrusions, which seems to postulate a close
connection between igneous rocks and ore deposits, as advocated
by such
authorities as
While the importance
Weed, Kemp, Lindgren, and Emmons.

magmatic waters as agents of primary
of
deposition is quite generally admitted, it is true that the metalliferous minerals as originally deposited have not always been
but they have become

concentrated at a later date by meteoric waters, as at Bisbee,
Arizona.
(See Ransome, under copper references.)
Posepny
(84), in his work on the Genesis of Ore Deposits, distinguishes
sufficiently concentrated to serve as ores,
between descending surface waters, or vadose circulations, and

1
Carnegie Institution, 1908.
ECONOMIC GEOLOGY
442
ascending waters from great depths. It is the former that have

been active in the secondary concentration of ores.
Composition of Ground Waters (5, 13, 140, 142, 147). The ground
waters show a variable temperature and always a variable quantity of dissolved matter.
The waters of sedimentary rocks, beyond the influence of igneous intrusions, are mainly of carbonate character. In chloride
waters, sodium and calcium are prevalent, and even calcium
and sulphate ones are not uncommon, but sodium carbonate
waters are rare in mining regions. The waters are chiefly cold,
although many tepid ones, and even some hot ones occur. Both
hydrogen sulphide and carbon dioxide may be present in either
hot or cold waters.
In the older igneous rocks, where the effects of vulcanism have
The surface waters in these,
subsided, there is less variation.
where free from disturbing influences, are of the calcium carbonate type, but may often show sodium chloride, ferrous and
magnesium carbonates, and even much silica. If the rocks
contain pyrite, sulphuric acid may be present locally, together
with sulphate of lime, alumina and iron.
Ascending waters in igneous rocks of recent or Tertiary volcanic
activity are often tepid or hot.
They may carry sodium chloride,
or sodium carbonate with carbon dioxide.
Mine Waters (110, 140, 146, 148).

These are usually surface
waters, whose composition is modified by the presence of soluble
salts derived from the decomposing minerals of the ore body, or
igneous sources. They may therefore contain both metallic and
non-metallic elements, and show the power of water to transport
different elements in solution.
The analyses on page 443 will
serve for purposes of illustration.
Metalliferous Deposits from Springs (141, 149, 150, 153).
The composition of many spring waters also affords further
testimony of the ability of underground waters to serve as ore

carriers.
Moreover, occasional examples of metalliferous deposits
now being formed by springs are sometimes found as shown
below.
Weed
has described a hot spring near Boulder, Montana (153),

depositing auriferous quartz, and the deposit is pointed
out by him to be identical with silver- and gold-bearing quartz
veins of the region between Butte and Helena, Montana. Of
which
still
is
more
interest
is
the collection,
by evaporation,
of copper
ORE DEPOSITS
ANALYSES OF MINE WATERS
(Parts per million)
443
ECONOMIC GEOLOGY
444
probably deposited when the spring waters issued at a

Higher up the slope is a narrow vein, carrying small
amounts of gold and silver in a gangue of colorless fluorite and
some barite, and capped by a calcareous tufa. The latter is supposed to have been deposited at the surface while the fluorite
fluorite,
higher level.
was precipitated farther down in the vein fissure.

At Steamboat Springs, Nev., the hot chloride waters are depositing siliceous sinter (Plate XXXIX, Fig. 2), which contains mercury and antimony in small amounts, while stibnite crystals have
been found in some of the spring basins.
Mode of Concentration.
From what has been said above we
see that water
is
not only widely distributed in the rocks, but also
serves as a carrier of mineral matter.
tant concentrating agent, whatever
its
It is, therefore, an imporsource.

While cold water,
from impurities, has comparatively little solvent power,

the presence of acids or alkalies materially increases its solvent
capacity, while heat and pressure have also a great influence.
free
Before considering the causes governing the precipitation of

ore minerals in cavities or solid rocks, we may turn to a discussion
of the deposits formed by waters of magmatic origin.
Under magmatic emaDeposits from Magmatic Emanations.

are
included
or
nations
gases, vapors,
liquids, given off by molten
-
magmas
during cooling.
These emanations
(37-40),
actually in process of emission
be determined from those

from cooling igneous magmas, or
may
from those which remain imprisoned in the rocks.

As evidence of the variety of the former we
nations identified at two well-known volcanoes:
may
NH
list
the following ema-
N a2SO 4 -CaSO 4 Li 2 (SO 4 ) 3

4 C1, FeCl 3
Vulcano, S, Te, As.S., B 2O 3 NaCl,
A1 2 (SO<) 3 Tl, Rb, Ce, Co, Zn, Sn, Bi, Pb, Cu, I, P.
Vesuvius, 1895. HC1, SO 2 H 2 S, CO 2 S, CaSO 4 iron and copper chlorides,
Fe 2 O 3 Se, HF, HBr, NaHCO,.
4 C1, CuO,
NaCl, KC1, Na 2SO 4 K 2 SO 4
The springs of Carlsbad, Bohemia, which are supposed to be or magmatic
derivation show CO 2 and salts of the elements Cl, F, B, P, S, Se, Tl, Rb, Cs,
As, Sb, Zn, Na, K, Li, Ca, Mg, Sr, Ba, Fe, Mn, Al and Si.
,
NH
In order to point out more clearly the several processes by which
be deposited from magmatic emanations it may be well

moment to the molten magma and consider certain
which
take place during the period referred to.
changes
A study of large intrusive masses has shown us that the molten
mass after coming to rest sometimes tends to separate into two
ores
may
to turn for a
ORE DEPOSITS
parts, the
tween.
445
one basic, the other acid, with a gradational zone beacid portion may be either the outer or central part
The
of the mass.
segregation of metallic minerals

as a whole does not split up.
magma
a differentiation occurs,
may
occur,
even
if
the
But whether or not such

the molten magma, after coming to rest,
and upper portion, the contraction incident to solidification causing numerous fractures. Into these there
may be forced molten rock from the still uncooled lower portions
will cool first in its outer
water and gases forced out of the solidifying parts

magma. This water, however, must be in a vaporous form,
because the heat is undoubtedly sufficiently great to raise its temperature above the critical point, and the pressure is likewise heavy.
In many cases no doubt the fissure may become filled by a mixture
of water and magma, the former in such excess that it may be difficult to say whether this should be called an igneous fusion, or a
watery solution, for under pressure water can mix with a magma
of the mass, or
of the
all proportions, giving us a series of mixtures, with a fused

at one end and a hot solution at the other.
in
mass
Many magmas in cooling give off mixtures of watery vapors

and gases (such as fluorine, boron, etc.) and these before leaving
the igneous mass no doubt extract metallic or other elements and
carry them along, only to deposit them later, either in the outer
;
parts of the cracks in the border of the intrusion or in the surrounding rocks.
As these emanations from the
magma get farther away from it,

where temperature and pressure are less, the watery vapors condense, and these hot solutions (magmatic or juvenile waters) gradually work their way towards the surface, sometimes reaching it,
and flowing out as hot springs.
It is possible and indeed probable that as they reach shallower
depths they may become more or less mixed with meteoric waters.
These magmatic emanations with their burden of mineral matter
may not only deposit this at a varying distance from the intrusive,
but they in many cases often attack the rocks through which they
pass, altering them to a marked degree, and in addition dissolve
materials from the rocks they permeate.
The kind of materials deposited and the character of the alteration depend to a large degree
upon physical
conditions, primarily
temperature and pressure.

If
the deposition and alteration occur while the magmatic emana-
ECONOMIC GEOLOGY
446
a vaporous form (due to high temperature and

is termed pneumatolysis (gaseous).
If it
is in liquid form, it is termed hydatogenesis
In some instances both gases and liquids may be pres(aqueous).
ent, the work then being gas-aqueous or pneumato-hydato-genetic.
tions are
still
in
pressure), the process

occurs when the water
It
is
naturally difficult to prove in
many
cases whether the
phenomena observed were produced by pneumatolytic
or hydato-
genetic processes.
Certain important types of deposits, formed under these varying physical conditions,
Pegmatite Dikes
may now
be referred
to.
The
last unconsolidated
be forced out from the
parent mass to form dikes. These dikes, which may be of either
basic or acid character, will in general contain the same constituents that are present in the parent magma, but in different
When
proportions, certain residual products being in excess.
coarse grained these dikes are termed pegmatites.
Basic rocks
like gabbros may be accompanied by pegmatites containing
(2,
portions of an intrusive
13,20, 21).
magma may
chiefly plagioclase feldspar and pyroxene, while granites are

accompanied by those consisting chiefly of feldspar, quartz and
muscovite, as well as cassiterite, tourmaline, topaz, monazite,

or even other rare minerals.
An important feature is the presence of volatile substances,

mineralizers (including watery vapor), which tend to lower the
solidification point of the mass.
Indeed, the temperature according to Lindgren may be lower than 500 C., and this combined with
the fluidity of the mass, due evidently to a high water content,
undoubtedly permits the pegmatite to force its way into many
rocks along the separation planes.

Of the mineralizers, fluorine and boron seem to favor acid
pegmatites, while chlorine, phosphorus and sulphur are present
in the basic ones.
Pegmatite
dikes form an interesting
and important
link in
the chain of magmatic products, and while rich in minerals, are

not important as sources of the ores. They have been worked
South Carolina (Ref. 10, Tin) and South

For gold, as at Silver Peak, Nev. (Ref.
for bismuth in the New England district of New South
92, Gold)
Wales; and for molybdenite in Norway. New South Wales and
for cassiterite as in
Dakota
(Ref. 14, Tin).

;
Queensland.
1
See Harker, Natural History of Igneous Rocks, p. 293.
\
ORE DEPOSITS
High-Temperature Veins.
447
These form a
series related in
to the pegmatite dikes.

The latter were intrusions, containso
much water as to be classed properly as aqueo-igneous
ing
fusions, and having naturally rather sharply defined boundaries.
way
The high-temperature
forced out from a cooling
veins
magma,
represent magmatic products

consisting probably of a mixture
and gases, with other substances in solution, the whole

under
high pressure and temperature. The latter is probabeing
not
in
excess
of 575 C., the inversion point of crystalline
bly
1
nor
is
it
supposed to have been below 300 C., and the
quartz,
water being heated above its critical temperature was undoubtedly
in a vaporous form.
of water
characteristic feature of these veins
metasomatic alteration
of
is
the frequently intense
rock, which may result

into a coarse-grained mineral
the wall
in the conversion of the latter
aggregate.
The evidence
of these conditions is shown by the presence of

minerals (p. 458), some of which
high-temperature
essentially
in
the
These include
crystallize only
presence of mineralizers.
pyroxenes,
amphiboles, garnets, apatite, ilmenite, tourmaline,
brown and green micas, spinel, soda-lime feldspars, cassiterite, arsenopyrite, pyrrhotite and some others.
The veins have been formed at great depth, and while in some
topaz,
cases they are close to the intrusive, or even within it, at others
they may be some distance from it, but still initially at such
depth as to maintain
the
conditions
of
temperature
and
pressure.
Several classes of veins seem to belong to this group, as follows:
Veins of
1.
cassiterite,
wolframite and molybdenum, the
first
named being
specially important.
2. Gold-bearing veins in crystalline schists as those of the southern Appalachians, southern Brazil, southeastern Alaska, Ontario, Lead City, S. Dak.,
and Kalgoorlie, W. Australia.
3.
Eng.;
Copper-gold-tourmaline deposits, represented by those of Cornwall,

3
Cactus Mine, Utah; Rossland, British Columbia; and Meadow Lake,
Calif."
1
F. C.
Jour. Sci.,
2
Those
Wright and E.
S.
Larsen, Quartz as a Geologic Thermometer, Amer.
XXVII:
147, 1909.
not referred to in the following footnote are discussed in subsequent
chapters on those metals.

s
Vogt, Krusch and Beyschlag, Ore Deposits, Translation,
4
Lindgren, Amer. Jour. Sci., XLVI: 201, 1893.
I:
431.
ECONOMIC GEOLOGY
448
4.
Lead-silver
tourmaline veins
associated
with the Helena batholith,
Montana. 1
5.
Cobalt-tourmaline veins of San Juan, Chile. 2
These include
(24-36).
Contact-Metamorphic
Deposits
masses of metallic minerals and silicates which are found in some
sedimentary rocks, chiefly calcareous ones, near their contact with
igneous intrusions, specially those of a more or
less acidic char-
acter (Fig. 136).

It has long been known that an igneous mass may often exert
considerable effect on the rocks which it has penetrated, sandstone,
Section through a contact-metamorphic zone; showing (a) intrusive

Contact-metamorphic zone
quartzite;] (c) limestone; (d) shale.
shown in stippled area, including ore in black. (From .Rt'es and Watson,
FIG. 136.
rock;
(6)
Engineering Geology.)
for example, being altered to quartzite, clay or shale to hornstone,
and limestone to marble.

is
Moreover, the contact-metamorphism
accompanied by the development of
new minerals
in the wall
rock.
Thus
in limestone there
may
be formed garnet, wollastonite,
epidote, diopside, amphibole, wernerite, vesuvianite, etc.; while

in aluminous rock such as shale and slate we find andalusite, silli-
manite, biotite, etc.

It was formerly believed by many that these silicates, as in
the limestones, must be segregated and recrystallized impuri1
Knopf, Econ. Geol., VIII: 105, 1913.
Stutzer, Zeitschr. prak. Geol.,
XIV:
294, 1906.
ORE DEPOSITS
ties,
and hence could form only
in
449
impure rocks, the pure lime-
stones yielding simply a marble.

Investigation of these contact zones has
shown
us,
however,
that they contained many elements which were not found in the
limestone outside of this belt of metamorphism, and we are
therefore driven to the conclusion that they represent substances
which have been given
off
by the magma and lodged
in the lime
rock.
The theory usually advanced to explain the origin of these

contact-metamorphic deposits, is that the original magma contained various volatile substances in solution, such as water,
carbon dioxide, sulphur, boron, chlorine, and fluorine, which on
the cooling and solidification of the magma are forced out into the
surrounding rocks. The watery vapor was evidently heated
above
its critical
temperature (365 C.).

of the other elements found in contact
are
supposed to have been carried out by
metamorphic deposits
their
form of combination during emission
but
exact
these vapors,
it
has
been suggested that some were
is not known, although
The metals and many
combined with fluorine or boron.

These were forced out into the fissures or pores of the limestone, and replaced the latter wholly or in part, the silica, alumina
and iron combining with some of the lime to form different silicates.
While contact-metamorphic effects may extend to a distance

from the eruptive, ore deposits rarely extend more
than a few hundred feet, and often terminate suddenly.
of 1 to 2 miles
Normal granites or other highly acid intrusives may produce

contact metamorphism, but do not as a rule form ore deposits.
Intrusives like monzonite, quartz monzonites or granodiorites
are important associates of contact-metamorphic ores, as can be
seen
by the numerous occurrences in the Cordilleran region of

The more basic rocks are of less importance,
the United States.
although
they sometimes yield contact-metamorphic ores in
limestones as in the case of gabbro at Hedley, British Columbia,

and diabase at Cornwall, Pennsylvania.
Contact-metamorphic deposits were probably formed at depths

thousand feet, and possibly in most cases within the
of several
zone of fracture. The temperature according to Lindgren was

probably high, from 300 C. to 600 C.
Contact-metamorphic deposits are usually of irregular shape
ECONOMIC GEOLOGY
450
and somewhat bunchy
in character, but very little can be said

to
which they may extend. Where the
the
depth
regarding
followed
certain beds a tabular structure often
has
development
results.
The common
ore minerals found are magnetite
and
specularite,
together with such sulphides as bornite,

pyrrhotite,
and
silver
and more
may
chalcopyrite, pyrite,
zinc blende.
Some gold
rarely galena and

be present, but tellurides are probably very rare.
Molybdenite and tetrahedrite are known.

The gangue minerals are in general lime-alumina silicates,
and include garnet l (Fig. 137), wollastonite, epidote, tremolite,
FIG. 137.
Section of garnetiferous limestone from Silver Bell, Ariz,

garnet; black, sulphides.
diopside, hedenbergite, zoisite, vesuvianite, ilvaite, quartz and

calcite.
The first of these is especially abundant and may form
nearly the entire mass of the rock. There may also be present
minerals containing boron, fluorine, and chlorine, such as axinite,
tourmaline, fluorite, scapolite and danburite.
Some
difference of opinion exists regarding the details of the
contact-metamorphic process.
Thus, while most geologists are agreed that most of the constituents of the ore body are derived from the magma, others like
1
Mainly andradite, the iron-lime garnet, and
alumina garnet.
less often grossularite,
the lime-
ORE DEPOSITS
451
some magmatic emanations, hold that the

are mainly the result of the recrystallizaminerals
gangue
This means the
tion of original constituents of the limestones.
removal of an excess of certain constituents and a consequent
Leith, while admitting
silicate
reduction of volume, a fact which is said not to be proven by the

evidence.
In strong contrast to the usually accepted theory of the formation of contact-metamorphic deposits, is that advanced and
field
energetically defended
by A. C. Lawson
(30),
who contends
that
they originate by the action of meteoric waters. According to

him any circulation of groundwater will be profoundly disturbed
by igneous
of this there
As a result
injections into sedimentary terranes.
would be developed an upward circulation following
along the periphery of the heated mass, and competent, he conFractures

siders, to form the characteristic lime-silicate zones.
country rock caused by the igneous intrusion, or shrinkage

cracks in the latter due to crystallization or cooling, would afford
channelways for the rising waters, and these by bringing in
material leached from the surrounding region, or by additional
in the
leaching of the intrusive, could deposit these in the area referred

to usually as the contact-metamorphic zone.
W.
O. Crosby has also suggested that contact-metamorphic
deposits are the work of meteoric waters (26), while Klockman

believes that they represent pre-existing ore bodies altered by
intrusives (29).
Other divergent views refer to the question of whether or not

the
magma was
consolidated before mineralization began. Some

metamorphism of the limestone occurred
writers consider that the

first,
followed by mineralization.
order of succession of the minerals
The
is
certainly not always
the same, and according to different observers the sulphides sometimes follow the silicates, or at other times are contemporaneous
with them.
Contact-metamorphic deposits, though sometimes rich enough

to mine whpfe not secondarily enriched, need this process in many
cases to make the ore workable. This was well illustrated in
the case of the Morenci, Arizona, copper ores.
Although this class of deposits was recognized by von Groddeck,

as early as 1879, he failed to appreciate the true importance of
the associated intrusive. In more recent years the writings of
Vogt,
Kemp, Weed, Lindgren, and
Barrell have greatly increased
ECONOMIC GEOLOGY
452
our knowledge of the true nature of these interesting deposits, and

we now know, moreover, that they form a very important and
somewhat common type, which in the United States is restricted
mainly,
known
however,
in
the
to
Pacific
Cordilleras.
Canada, the Yukon, Alaska, and
They
many
are
also
other coun-
tries.
Contact metamorphic deposits
may be
1.
Magnetite deposits.
Examples: Iron Springs, Utah,
2.
Chalcopyrite deposits.
classified as follows
(13)
2
1
3
Fierro, N. Mex., and Cornwall, Pa.
Chief ore minerals, chalcopyrite, pyrite, pyr-
molybdenite and specularite.

6
4
6
Examples: Clifton, Ariz., San Pedro, N. Mex., and Cananea, Mex.
Galena-blende deposits.
7
Examples: Magdalena Mines, N. Mex.
rhotite, sphalerite,
3.
4.
Arsenopyrite-gold deposits.
Chief minerals,
arsenopyrite
and pyr-
rhotite.
8
5.
Examples: Hedley, Brit. Col.

Gold deposits.
9
Examples: Cable Mine, Mont.
6. Cassiterite deposits.
Examples: Pitkaranta, Finland,
Ore Deposits Formed
10
Seward Peninsula, Alas. 11
at Intermediate Depths.
Following the
succession of deposits formed under conditions of gradually decreasing temperature and pressure, there has been recognized
another group formed presumably at intermediate depths, de-
by ascending hot waters, and evidently genetically conwith

intrusive rocks.
nected
It is, of course, difficult to tell the exact depth of their forma-
posited
which Lindgren has estimated within a somewhat wide

range of 4000 to 12,000 feet; but it can sometimes be approximately judged by determinating the thickness of overlying rock
tion,
removed by
is
erosion.
An
important character of these deposits
the absence of high-temperature minerals.

1
3
4
5
6
7
8
9
10
11
Leith and Harder, U. S. Geol. Surv., Bull. 338, 1908.

Graton, Ibid., Prof. Pap. 68: 313.
Spencer, Ibid., Bull. 430.
Lindgren, Ibid., Prof. Pap. 43, 1905.

Lindgren and Graton, Ibid., Prof. Pap. 68.
Emmons, S. F., Econ. Geol., IV: 312, 1910.

Lindgren, U. S. Geol. Surv., Prof. Pap. 68: 241.
Camsell, Can. Geol. Surv., Mem. 2, 1910.
Emmons, W. H., U. S. Geol. Surv., Bull. 315: 45, 1907.
Vogt, Krusch and Beyschlag. Lagerstatten.
Knopf, U. S. Geol. Surv., Bull. 358, 1908.
ORE DEPOSITS
453
The deposits are often fissure veins or a related type, and while
the minerals frequently fill open fissures, replacement deposits
are not uncommon, and where limestone is the country rock,
may
be of considerable extent.
The most important metals

copper, lead
and
in these deposits are gold, silver,
zinc, but the deeper-formed members of the
molybdenum, bismuth, tungsten and arsenic.

Sulphides, arsenides, sulpharsenides and sulphantimonides are
the prominent compounds, while oxides are rare. Quartz is
the chief gangue mineral, but carbonates are common.
The country rock usually shows intense alteration next to the
ore, feldspathic and ferromagnesian rocks yielding
sericite,
carbonates and pyrite, and calcareous rocks often showing siliciThe last-named process may also be accompanied by
fication.
may
series
carry
dolomitization.
The following types, with examples added,

longing to this class:
1.
Gold quartz veins
of California
may be enumerated
and Victoria type.

and Nova
Intei ior Cordilleran region; 1 Victoria, Australia, 1

2. Gold-bearing replacements in limestone.
gold ores of Black

3.
4.
Hills, S.
Sierra
as be-
Nevada, 1
Scotia. 1
Mercur, Utah;
siliceous
Dak. 1
Gold-bearing replacements in quartzite. Delamar Mine, Nevada.

Gold-bearing replacements in porphyry. Cripple Creek, Colo,
Little
part).
(in
3
Rocky Mountains, Montana.
5. Silver-lead veins,
a.
b.
c.
including
Quartz-tetrahedrite-galena veins.
4
Organ, N. Mex.
6
Tetrahedrite-galena-siderite veins. Wood River, Idaho.
Galena-siderite veins. Co3ur d'Alene, Idaho. 6
Lead-silver veins with calcite, siderite and barite.
6.
Przibram, Bohemia.
7. Pyri tic-galena-quartz
veins.
Arizona. 8
8. Silver-lead
replacements
6
Clausthal, Ger-
many and
in
Freiberg,
Saxony;
Cerbat
Aspen * and Leadville,

Park City and Tintic, Utah; 8
limestones.
Lake Valley, N. M.;
Colo.; Eureka, Nev.;

Sierra Mojada, N. Mex. 6
9. Tungsten veins.
Boulder County, Colo. 9
1
"*
*
4
See references under Gold.
Emmons, S. F., Amer. Inst. Min. Engrs., Trans., XXXI: 658,

Emmons, W. H., U. S. Geol. Surv., Bull. 340: 98, 1908.
Lindgren and Graton, U. S. Geol. Surv., Prof. Pap. 68: 209.

Lindgren, Ibid., 20th Ann. Kept., Pt. 3: 190, 1900.
6
See under Lead-Silver ores.
*
See under Lead-Silver ores.
8
Schrader, U. S. Geol. Surv., Bull. 397, 1909.
8 See under
Tungsten.
5
range,
1901.
ECONOMIC GEOLOGY
454
10. Native silver veins.

With cobalt and nickel as at Cobalt, Ont.,*
and Annaberg, Saxony; 1 with zeolites, as at Kongsberg, Sweden.
2
2
11. Copper veins.
Butte, Mont., and Virgilina, Va.
2
Mt. Lyell,
12. Pyritic replacement deposits.
Rammelsberg, Harz;
2
2
2
Shasta
Rio
County, Calif.;
Tyee, Vancouver
Tasmania;
Tinto, Spain;
Island. 2
These inOre Deposits Formed at Shallow Depths (13, 21).

number of fissure-vein deposits, found in the Cordilleran
region, and carrying gold with much silver, as well as subordinate
amounts of lead, zinc, and copper. The fact that they are found
clude a
in flows of volcanic origin indicates their formation at comparatively shallow depths, that is, from a few hundred to four or five
thousand feet. They include most of the veins of western Nevada,
the San Juan region of Colorado, Cripple Creek, Colorado district, etc.
Gold and silver are prominent, although the former is more

abundant and the native gold usually more finely divided.
Like the deeper veins, they may carry pyrite, galena, and sphalerite, but in addition chalcopyrite, arsenopyrite, argentite, and
stibnite are characteristic ore minerals.
gangue mineral, and

are also found.
Quartz
is
calcite, dolomite, siderite, barite,
Adularia
is
also widespread as a
common
and
fluorite
gangue mineral.
somewhat with the different rocks. In

moderately acid rocks sericitization and even pyritization seem
to be common near the vein, and propylitization3 farther away.
Metasomatism
varies
In basic igneous rocks, propylitization may extend close to the

Silicification
vein, but sericitization occasionally takes its place.
of the wall rock may occur, especially in rhyolites and sometimes
in calcareous rocks.
change in the character of the vein mineralization is somewhen earlier calcite gangue is replaced by quartz
times shown, as
and
adularia.
Since these ores are of shallow origin, they are formed in the
zone of fracture, and are therefore found filling cavities of varied
origin
and wide
distribution.
Deposits formed at shallow depths

as follows:
1
may be
separated into different types
See under Nickel-Cobalt.

See under Copper.
*
This consists in the development of chlorite and epidote as well as pyrite, from
dark silicates, and the breaking down of feldspar to quartz, chlorite, and epidote,
the rock assuming a dull green color.
2
ORE DEPOSITS
1.
Quicksilver deposits.
2
2. Stibnite deposits.
3.
455
Gold-quartz veins.
a. In andesite, Brad, Transylvania; Hauraki Peninsula, N. Z.
De Lamar, Ido.
b. In rhyolite.
4.
3
Argentite-gold-quartz veins.
5.
3
Argentite veins.
6.
Gold-telluride veins. 3
7.
Gold-selenide veins. 3
Tonopah and Comstock Lode, Nev.

Pachuca and Guanajuato, Mexico.
8.
Base-metal veins. 3
9.
Gold-alunite veins. 3
Cripple Creek, Colorado.
Republic, Washington.
San Juan region, Colorado.
Goldfield,
Nevada.
At
Deposits Formed at the Surface by Hot Waters (83).
or near the surface mineral deposits may be formed by hot springs,
but they are not usually of economic importance.
Such springs may deposit earthy carbonates as sinter, and silica
as opal or chalcedony. Ore minerals developed under these conform are stibnite, marcasite, and cinnabar,
but other sulphides have been detected by chemical means. Calcite, fluorite, barite, and celestite may also develop.
According to what has been said above there is a somewhat
continuous series of deposits from the deepest to the higher and
cooler zones, the mineral combinations gradually changing from
those of magmatic and contact-metamorphic conditions, to those
ditions in crystallized
known
to exist in surface hot springs.
The deposition of ores in the rocks is

by the presence of cavities along which the
ore-bearing solutions freely pass, and consequently a great many
ore deposits occur in such spaces. There are a number of different
ways in which cavities may be formed in rocks. The percolation
Formation of
Cavities.
greatly facilitated
of surface water through certain ones, such as limestones, often

results in the formation of solution cavities,these in many instances
attaining the size of veritable caverns ; a soluble rock may contain
more
lapses
or less insoluble material, such as clay or chert, which colwhen the surrounding rock is dissolved, and partly fills the
At times the more resistant parts are so bound

together that they remain in their original position, forming a
porous mass, in the cavities of which mineral matter is later decave thus formed.
posited.
Dynamic disturbances produce

1
2
3
cavities of variable extent in
See under Mercury.

See under Antimony.
See under Gold-silver.
ECONOMIC GEOLOGY
456
many
the
These range from microscopic cracks, like

enormous faults of great depth and
different rocks.
rift
planes of granite, to
linear extent,
of almost
all
joint planes so common in the rocks

Fault fissures form one of the most important
and include the
regions.
types of passageways for ore-bearing solutions.

irregular, branching,
and partly
filled
the breaking of the rock during the

plane.
resulting
by
They
are often
fault breccia, caused
movement along
by
the fault
third important group of cavities in the rocks are those

from shrinkage of the mass, which may be due to
(1) shrinkage during cooling, as in igneous rocks; (2) shrinkage

during certain forms of replacement. For example, the change of
calcite to dolomite may be accompanied by a shrinkage of the
mass, which renders the dolomite more porous than the original
rock; and in the alteration of siderite to limonite there is a shrink-
A fourth type of channelway for

age of fully 20 per cent (139).
the passage of underground water is the contact plane between
two quite different kinds of rock, one of them~TairTy dense and
impervious.
clastic rocks
Gas
cavities of lavas
and the pore spaces
of pyro-
may also serve as openings for ore deposition.

Open cavities may, acDeposition of Ore in Open Cavities.
cording to general belief, exist to a depth of many thousands of

If rock pressure alone were active, they
feet below the surface.
could not theoretically exist below the zone of fracture, but it
seems probable that hydrostatic pressure due to gravity may to
some extent counteract rock pressure.
There
is
evidence to show that some large cavities must have

and here it is supposed that the force of
existed at great depths,
crystallization has been sufficient to spread the walls apart. Becker

of such a force, 1
and Day have demonstrated the actual existence
but Lindgren points out that it seems scarcely possible to attribute

such power to it as would be necessary to open deep-seated crev-
room for the crystals, and moreover that it

would " seem impossible that under these conditions comb structure and coarsely, even-grained quartz could be produced."
Graton 2 suggests the crevices formed below the zone of fracture
have been opened by the pressure of solutions forced out of the
vices sufficiently to form
cooling
magma.
In some cases the

Precipitation of Metals from Solution.
metalliferous and other minerals found in ore deposits have no
.
U.
Wash. Acad.
Sci.,
VII: 283.
S. Geol. Surv., Bulletin 293.
ORE DEPOSITS
457
doubt been taken into solution by surface waters, and precipitated

at no great depths; but in the majority of instances the metals
were taken into solution at some point considerably below the
point of precipitation, where heat and pressure were evidently
The ascent then of these solutions toward the surface
high.
where temperature and pressure were low, would reduce the
solvent capacity of the liquid and cause deposition.
As has been pointed out by Lindgren (83) the physical conditions during deposition, especially temperature and pressure,
are of great importance in determining the mineral association
in ores formed by deposition from solution.
Certain minerals, for example, are very stable under high

pressure and temperature, and could not therefore exist under
conditions prevailing near the surface.
That is to say, that
"
the different minerals have their
critical level/' above or
below which they cannot form or exist. Other minerals are

"
termed persistent minerals," because they have a large interval
of existence. 1
The conditions under which different ore minerals, as well as

some others, may exist are given in the following table (pp. 458461) compiled
2
by Emmons.
The
deposition of the metals may have been due, however, to

other causes, such as the mingling of waters, resulting in chemical
reactions, contact of the solution with reducing agents such as car-
bon, ferrous sulphate, or hydrogen sulphide; or where the pre,

cipitation occurs near the surface, by oxidation.
Other conditions may, however, operate to cause precipitation,

for, as shown by Sullivan (86), the natural silicates have the
"
power of precipitating metals from solution of salts, while at the
same time the bases of the silicates are dissolved in quantities
nearly equivalent to the precipitated metals." The bases which
most commonly replace metals in such a process are potassium,
sodium, magnesium, and calcium, and the metals are precipitated
as hydroxides or basic salts.
Cupric sulphide, for example, is
as
a
basic
similar to brochantite or
cupric
sulphate
precipitated
langite.
The same
investigator (87) has also found that
when a
solution
of ferric sulphate is passed through a Pasteur filter, 18 per cent of

the iron is held in the tube. Repeated passage of the same solu1
a
A. Grubenmann, Die Kristallinen Schiefer, Berlin, 1904, p. 55.

Econ. Geol., Ill: 611, 1908.
ECONOMIC GEOLOGY
458
BY
BY
ZONES
LPHIDE
NEAR
NEAR
DEPTH.
DEPTH.
MODERATE
MODERATE
AND
MINERALS.
ROCKS
ROCKS
OF
OF
LLOW
SHALLOW
MINERALS
OXIDE
DEPOSITS
CONTACT-M
DE
AND
AND IGNE
IGNEOUS
OF
EPOSITS
DEPOSI
ENRICHMENT
SEC'Y
Acmite
Actinolite
Adularia
Aegerite
Alum
Alunite
Albite
Allanite
Amalgam
Amphiboles
Analcite
Andalusite
Andradite
Anglesite
Anhydrite
Ankerite
Anorthite
Anthophyllite
Antimony
Apatite
Aquamarine
Apophyllite
Arfvedsonite
Argentite
Aragonite
Arsenic
Arsenopyrite
Atacamite
Augite
Auriehalcite
Azurite
Barite
+?
Bauxite
Beryl
Bismuth
Bismuthinite
Biotite
Bornite
Bort
Bromyrite
Brookite
.
Calamine
Calaverite
Calcite
Caledonite
Calomel
Cancrinite
Cassiterite
Celestite
Cerussite
Cerargyrite
Chalcanthite
Chalcedony
Chalcocite
Chalcopyrite
Chert
Chlorite
Chromite
Chrysocolla
Cinnabar
Cobaltite
ORE DEPOSITS
MINERALS.
459
ECONOMIC GEOLOGY
460
MINERALS.
ORE DEPOSITS
461
ECONOMIC GEOLOGY
462
Replacement, or Metasomatism (99-105). It is a well-known

under favorable conditions mineral-bearing solutions may
attack the minerals of the rocks which they penetrate, dissolving
fact that
FIG. 138.
Vein breccia from Freiberg, Germany.
The specimen shows fragments
of altered schist (S), which are in some

and in others more or less completely replaced by sphaland cemented by quartz (Q). Scattered grains of pyrite (P) are also
cases surrounded,
erite
(Z),
present.
(Specimen in Cornell
collection.)
them wholly
some
of the original burden

This replacement, termed
"
metasomatism," is an important factor in the formation of many
ore deposits, and may involve a total or partial loss of certain
constituents of the rock attacked and a gain of others, even to
or in part, and depositing

in place of the material removed.
the extent of
elements.
introduction of
entirely
new compounds and
ORE DEPOSITS
463
While some (100) believe that replacement may be accompanied by a volume change, others (102) assert that it proceeds
independent of molecular weight,
molecular
volume,
and
specific
gravity.
The replacing solutions gain

entrance to the rock mass, along
fractures
of
different
sorts,
and
penetrate the rock first along the

smallest cracks, and then work
into the individual min-
their
way
eral
grains
along
their
cleavage
planes until they finally permeate

the entire mass (Figs. 139, 140, FlG x 39.
-Photo-micrograph of a
and 142). The reactions between
section of quartz conglomerate,
the
dissolved
mineral,
and
showing replacement of quartz
the
(white),
original rock probably take place

in films of the solution coating the
diam.
Sci.,
by pyrite
(black),
(After Smyth,
XIX,
X25
Amer. Jour.
1905.)
grains.
Metasomatic processes show great variety, and are not confined
FIG. 140.
Pyrite replacing hornblende, Mineral, Louisa County, Va.

Black, pyrite; gray, hornblende; white, quartz.
to one kind of rock or "mineral.
metasomatism
may
In
its
often be seen in
X35.
simplest form the result of

f ossiliferous
rocks,
where
ECONOMIC GEOLOGY
464
organic remains have been replaced by common mineral compounds, as in the replacement of the lime carbonate of corals by
From
quartz, or the replacement of molluscan shells by pyrite.
such simple conditions there is every gradation to the complete replacement of extensive areas of rock by ore, or to the
extensive operation of metasomatism along the walls of fissure
veins.
The complexity
may
of metasomatic processes referred to above

be due to variations in temperature, character of rock, and
nature of solution.
Metasom-
may take place through a

wide range of temperature, but
heat greatly aids the process, and
atism
the replacing solutions while usually liquid,
may
Of the many
also be gaseous.
different rocks af-
fected, limestones are
most favor-
able to replacements, while those

high in alumina are least easily
attacked.
The original structure and even

the texture of the rock
FIG.
141.
Replacement
vein
in
syenite rock, War Eagle Mine,

Rossland, B.C. (a) granular orthoclase with a little sericite; (6) sec-
illustrations of the
ondary
sometimes seen
quartz;
ary
biotite;
(c)
chlorite;
pyrrhotite.
Amer.
Inst.
XXX.)
secondary
black, second-
(g)
(After Lindgren,
Min. Engrs., Trans.
may
be
preserved, although its mineral
composition
is
completelyaltered,
former being
in silicified lime-
stones, or of the latter in replaced

porphyritic rocks, in which the
outlines of the
phenocrysts are
still
preserved.
replacing mineral is referred to as the metasome, while
if it shows crystal outlines it is called a metacryst, and some minerals in replacement show a greater tendency to develop crystals
The
than others.
Replacement at high temperatures is usually indicated by

complete recrystallization, the development of silicate minerals
with little or no water, and coarse texture. That performed at
lower temperatures commonly results in a much finer-textured
mass.
To definitely decide whether replacement has occurred, both
In hand specimens
field and laboratory study is often necessary.
ORE DEPOSITS
465
not always possible, without examination of a thin section

under the microscope, to decide whether the minerals present are
due to replacement or to simple interstitial filling.
Certain criteria representing both field and laboratory features
have been suggested (100) although all are rarely applicable to a
These are: (1) Presence of complete crystals in
single deposit.
it is
foreign rock masses; (2) Preservation of rock structures; (3)

Intersection of rock structures by replacing mass; (4) Absence
of crustification;
(5)
Presence of unsupported nuclei;
Va., mines.
X 20
Rela-
FIG. 143.
FIG. 142.
FIGS. 142 and 143.
(6)
Photo-micrographs of thin sections of ore from Austinville,

diam. crossed nicols. Shows crystalline granular dolomitic
limestone, and the filling of fine cracks accompanied by replacement of limestone grains along crystallographic directions by the sulphides. Very dark
Reentrant angles along marirregular areas in center represent sulphides.
gins of the sulphides and the spider-like arrangement of the sulphide areas as
a whole are well shown. (After Watson, Va. Geol. Sure., Bull. /.)
tion of replacement to fissures

of deposit.
As mentioned
variety.
before,
Non-metallic
and other
cavities;
and
(7)
Form
metasomatic processes show endless
minerals
may
replace
each
other
as
quartz replacing calcite, or metallics may replace nonmetallics,

as galena in limestone or pyrite in hornblende (Fig. 140); and
one sulphide may be replaced by another, as pyrite

chalcocite (Plate XLII), or sphalerite by chalcocite.
Although the process of metasomatism was recognized
lastly
by
by
Charpentier as early as 1778, it was generally disregarded, and

not widely accepted or recognized until many years later, and
geologists continued to assume that ores precipitated from solution were deposited in cavities.
Replacement was, however,
ECONOMIC GEOLOGY
466
United States, being applied by PumLake Superior copper deposits in 1873; by Emmons to
Leadville in 1886, and by Irving and Van Hise to the Gogebic
Range in 1887 to 1888.
finally recognized in the
pelly to the
Ore deposits of great size, as those of Leadville, Colorado,

or Bisbee, Arizona, may be formed by replacement, and a frequent expression of it is seen in the alteration of the wall rocks
of
many fissure
veins.
(See
Hydrothermal
alteration, p. 486.)
Ore bodies vary greatly in their

Forms of Ore Bodies (163).
form, and this character has at times been used as a basis of classification by some writers: but the more modern tendency is to use
genetic characters instead, making shape of secondary importance
Certain forms of ore bodies are so numerous as to
in the grouping.
deserve special mention.
Fissure Veins (2, 21,
fissure vein
may
125,
be defined
127, 128, 131,
(103)
133, 135, 138, 163).
a tabular mineral mass
as
occupying or closely associated with a fracture or set of fractures

in the inclosing rock, and formed either by filling of the fissures
as well as pores in the wall rock, or by replacement of the latter
(metasomatism). When the vein is simply the result of fissure
the ore and gangue minerals are often deposited in successive
layers on the walls of the fissure (Rico, Colorado), the width
of the vein depending on the width of the fissure and the boundaries
filling,
mass being sharp. In most cases, however, the oresolutions

have entered the wall rock and either filled its
bearing
or
replaced it to some extent, thus giving the vein an
pores
Therefore the width of the fissures does
indefinite boundary.
of the ore
not necessarily stand in any direct relation to the width of the

The term vein material is best
vein (138) (Butte, Montana).
used to apply to the aggregate of materials which
Vein stone, though sometimes used, is
ore body.
(Emmons)
make up the
less desirable
filling of a fissure often show a

banded structure of varying regularity termed crustification 1 by
Posepny (Plate XXXIX, Fig. 1 and Fig. 144), which may some-
Veins formed by the simple
times be brecciated by later movements along the fissure. Secondary bands may be formed after reopening of the fissures (Fig.
144), and such a movement may cause brecciation of the vein material.
1
There are many
The replacement
produce a banded
filled fissure
veins in which banding
of certain layers only in a

structure.
bed of
stratified
rock
may
is
also
PLATE
FIG.
1.
Banded vein from
Ciausthal,
Argillite wall rock, W, fragments of

crystallizing in the cracks.
FIG. 2.
Banded
vein,
(black)
same
locality.
Calcite,
XL
Germany. Sphalerite, S; Quartz, Q;

which have been separated by quartz
Sphalerite, S; Galena, G; Chalcopyrite,

streak of later quartz, Q.
(white)
(467)
ECONOMIC GEOLOGY
468
absent, the ore minerals and gangue being intermixed, but so related as to indicate probably simultaneous deposition of the two.
Later movement along

the
layer of
may
wall
vein
sometimes
f<irm
soft,
clayey
material, known as
gouge or selvage, be-
tween the vein
and
the country rock, but

where the vein filling
adheres closely to the

country rock it is said
to be frozen to the walls.
Where the
fissure has
not been
filled,
completely
thus leaving a
central
Section of vein in Enterprise mine, Rico,
FIG. 144.
Colo.
The
right side shows later banding
due to
reopening of the fissure. (After Ransome, U. S.

Geol. Sun., 22d Ann. Rept., II.)
different ores.
Among
the
commonest
space
into
which the crystals of

a
gangue
project,
comb structure is formed.
The bands in a
filled fissure
sist
of
may con-
gangue
and
ore alternating, or of
ore minerals seen in these
and sulphides
regions afford especially fine examples of banded
veins, notably those of Grass Valley, California, and Rico, Colorado.
Abroad the mines of Freiberg, Saxony, and Clausthal, Prussia, also
fissure veins are pyrite, chalcopyrite, galena, blende,
of silver.
Some
often yield magnificent specimens.
Even
in a single vein the ore
may follow certain streaks which are termed shoots (q.v.) or again it
may be restricted to pockets of great richness, which are known as
bonanzas.
In some veins the friction breccia or dragged in fragments of the

country rock form a considerable portion of the vein filling, and the
ore has been deposited in layers around these fragments.
Fissure veins in which metasomatic action has predominated
show great
boundaries
irregularity of width and an absence of well-defined

they also lack as a rule the symmetrical banding and
the breccias cemented by vein material.
There are
all
gradations
PLATE XLI
FIG
Stibnite and
Vein specimen from Przibram, Bohemia; Galena, G;
Galena and quartz, M; Dolomite, C; Quartz, Q; Fragments
'quartz, A;
graywacke wall rock, W.
FIG. 2.
Veinlets of tin ore in granite, Altenberg, Saxony.
(469)
ECONOMIC GEOLOGY
470
between these two types
of fissure veins
and even in a
single vein
simple filling may occur in one part and replacement in another.

Veins often split or intersect, and at the point of intersection or
splitting the ore is apt to
be
There are other reasons
richer.
variations in richness,
for
amgng the
most important being the character of the wall rocks, some

kinds being more easily replaceable or more porous than others.
Their
physical
character
will
moreover exercise considerable

influence on the shape and size
FHJ.
Section showing
145.
Tough rocks like

change in of the fissure.
gneiss, for example, give a clean-
character of vein passing from gneiss

to) to quartz porphyry ().
(After
Beck, Lehre von aer Erzlagerslatten :
fi
the fissure
133.)
'
is
^^
apt to
split fre-
quently, and therefore a vein

be workable in one kind of rock, but becomes worthless when
passing to another, since the profuse branching interferes with economical mining (Fig. 145). A dike may also cause local irregularities, and in a given region the fissures not uncommonly show great
may
variation in their direction.
west
veins
Thus
at Butte,
Montana
(q.v.),
east-
predominate,
while in the Silverton dis-
Colorado they cut
trict of
the rocks in
all
directions,
but the majority show a

north of east trend. In the
Monte
Cristo,
district
the
Washington,
veins
with w
northeast
trend
dominant
(Fig. 146).
are
pre-
Fissure veins vary considerably in their width,

swelling at some points and
pinching or narrowing at
others.
They also at times
show
lateral
(Ouray, Colorado) for inwhere the ore cuts

;
stance,
through
stratified
beds,
Tabulation of strikes of principal

Monte Cristo, Wash., district.
(After Spurr, U. S. Geol. Surv., 22d Ann.
FIG.
enrichment
into
146.
veins
in
Rept., II.)
which the ore-bearing solutions
ORE DEPOSITS
471
have spread out laterally along the planes of stratification or

other planes. It has been noticed in some veins, especially those
formed by replacement, that the filling varies with the wall rock,
at times changing suddenly; but where the vein is formed wholly
by the filling of an open fissure, the rock exerts no influence on
the character of the ore

wall
is
If
(138).
spoken of as the foot wall
the vein
is
inclined, the lower
and the upper one as the hanging
wall.
horse
is
a mass of rock broken
held between the walls of the

ore,
and
may
itself
fissure.
off
from the vein wall, and

surrounded by
It is often
sometimes be mineralized to a varying
degree.
Parallel fissures are not
uncommon, but the several veins do not

show
an
necessarily
equal degree of richness. Where the vein is of
FIG. 147.
composite character,
Linked veins.
that
is,
(After Ordonez.)
consisting of closely spaced parallel
accompanied sometimes by a mineralization of the interit is termed a lode.

vening rock,
The term vein systems is suggested for a larger assemblage of vein
fissures, which may include several lodes.
Subordinate fractures, such as little veins, that cross the material
fissures
included within the vein walls, are called veinlets or stringers.

The top of the vein is called the apex, and is occasionally traceIt does not necessarily outcrop at the
able for a long distance.
surface.
Linked veins represent a type in which the parallel fissures are

connected by diagonal ones (Fig. 147), giving a series resembling
the links of a chain.
ECONOMIC GEOLOGY
472
Gash veins are a special type of fissure vein of limited extent.

are formed by the enlargement of joint planes and some-
Some
times bedding planes.
They
are
characteristic
of the
upper
Mississippi Valley lead and zinc

region, but are usually of limited
and local importance.

In the simplest form they are a
vertical fissure, but develop into
extent
Gash vein with associated

"
"
"flats" (a) and
(b).
pitches
zinc
Wisconsin
(After
region.
Grant, Wis. Geol. and Nat. Hist.
F:G. 148.
types shown in Fig. 148. Other

S ash Veins ma y be the result f
torsional strain, as those
parrym
C
Surv., Bull. IX.)
cr
the
accom-
Catoctin type of
PP er 0reS
Bedded Vein.
'
This term is
sometimes applied to a deposit conforming with the bedding.
It is also called bedded deposit.
Among miners the term blanket
vein
is
commonly applied
to
any nearly
flat deposit.
deposits, found parallel with the stratification of sedimentary rocks, and sometimes of contemporaneous origin (Clinton iron ore).
Cross veins is a term applied to those which cross the stratifica-
Bedded
tion.
Lenticular veins are short lenses, frequently found in metamorphic rocks, and often scattered along a line, or lying more
or less parallel in a zone.
The manner in which fissure veins

Filling of Fissure Veins (131).
filled, and the source of the metals which they contain, formed a
been
have
most
subject of discussion among the earlier geologists. The several

advanced and the arguments for and against them are well set
forth in Kemp's paper (131), and it may simply be said here that most
fruitful
theories
now believe that the primary deposition of ores

was accomplished by solutions ascending along the
geologists
in fissure-vein
deposits
fissures,
which
sometimes spread out into the wall rocks, to a variable distance.
Other Forms of Ore Deposits.

Chimney is a term applied to ore
bodies which are rudely circular or elliptical in horizontal cross-sec-
stock is a somewhat
but may have great vertical extent.
similarly shaped ore body, but of greater irregularity of outline.
Fahlband is a term originally used by German miners to indicate
tion,
certain bands of schistose rocks impregnated with finely divided

It is occasionally
sulphides, but not always rich enough to work.
Stockwork
is
the
in
this
term
used
applied to a rock
country.
ORE DEPOSITS
473
mass broken
in different directions by short fissures, which may

be mineralized. Impregnation is a term indicating the occurrence of minerals in a finely disseminated condition in rocks, either
FIG.
149.
Section at
Bonne
Terre, Mo., showing ore disseminated through

limestone.
as a filling of open spaces or as a replacement of certain minerals.

Disseminated deposits (Fig. 149) is regarded as a better term by
some. Contact-metamorphic deposits, as now understood, represent
ore bodies formed along the contact of a mass of igneous and
LONGITUDINAL SECTION
FIG. 150.
FIGS. 150 and 151.
FIG. 151.
Sketch showing dimensions of an ore shoot.

gren and Ransome.)
(After Lind~
country or invaded rock (usually calcareous), the ore having been

derived wholly or in part from the intrusive mass (Clifton, Arizona,
in part).
If the term contact-metamorphic deposit is used for this
not necessarily conflict with the term contact
would
it
type,
deposit, applied to
any ore body occurring along the boundary

between two formations or two kinds of rock. Ore channels
include those ore bodies formed along some path which the mineral
ECONOMIC GEOLOGY
474
solutions could easily follow, as the
boundary between two
differ-
ent kinds of rock (Mercur, Utah).

Shear zones or sheeted zones represent a zone of rock broken by
numerous parallel and often closely spaced fractures, which may
be mineralized as at Cripple Creek, Colorado (Fig. 262).

Few ore deposits are of uniform character
Ore shoots (92-96)
throughout, indeed the occurrence of pay ore is apt to be more
.
or less irregular, the richer material being often somewhat reThese richer portions, if small, may be
stricted in its occurrence.
but
if
or
called nests,
large, the term ore shoot is commonly
pockets,
applied to them. According to some authors the ore shoot

includes only the richer portion of the workable ore.
(Van
Hise.)
Other writers, among them Emmons, Lindgren and Ransome,

employ the term ore shoot or pay shoot to signify the workable
part of a lode or similar deposit.
Ore shoots are commonly of irregular shape, and usually steep dip,
may be nearly horizontal.

Emmons the ore shoot, as a rule, has a longer axis
to
According
that forms a large angle with a horizontal plane. This longer axis
1
may be called the pitch length, and the horizontal dimensions along
although they
the level the slope length. Ore shoots are evidently caused by varying chemical and physical conditions in different parts of the deposit,
at the time the ore
was formed, thus causing a more abundant pre-
More
cipitation of the ore minerals in certain parts of the deposit.
abundant fissuring, or brecciation, in certain parts of the rock may
operate to promote deposition in those parts of the mass clay walls
may be influencing factors in guiding the ore solutions towards
;
certain spots
or intersecting fissures
may
permit the mingling of
reacting solutions, thereby bringing about more abundant precipitaThe existence of fissures in
tion of ore at these crossing points.
certain parts of the ore
body might produce additional deposition
in those parts, by serving as a guiding channel to either ascending

or descending enriching solutions.
The examples cited above apply especially to epigenetic deposits;
but if the term ore shoot is used in its broadest sense, one might
reasonably include ore masses formed by magmatic segregation.

Several attempts have been made to classify ore shoots, all of them
2
being on a genetic basis. Thus Van Hise divides them into three
1
Lindgren and Ransome.

Amer. Inst, Min. Engrs., Trans.
XXX:
27.
475
groups as follows: (A) those explained largely by structural features;
(B) those formed by the influence of wall rocks; and (C) those
formed by secondary concentration by descending waters.

Irving (92) has classified
them
as (1) shoots of variation, or those
which vary from the inclosing material only in relative richness of

the ore; and (2) shoots of occurrence, or those which occur in isolated positions with no other ore of any kind about them.
l
makes a
division into (1) paragenetic shoots, or those

at
the
time of the original formation of the ore
developed mostly
them
and
deposit inclosing
(2) postgenetic shoots, or shoots devel-
Winchell
oped mostly after the original formation of the inclosing ore deposit.
Ore
Secondary Changes in Ore Deposits (106-122, 155-158).
in
and
their
sometimes
are
often
changed
upper parts,
deposits
to a considerable depth, by weathering agents, while the lowerlying portions, below the ground-water level, are often enriched by
secondary processes.
The two zones each show a somewhat characteristic set of compounds. Thus in the weathered zones we find sulphates, carbonates,
silicates, oxides, chlorides, arsenates and native metals; while in the
lower zone the compounds are sulphides, tellurides, arsenides, and
antimonides.
^^Z
/
:
+ .L
B.xter
Tor,]
LeT.l
RU'el
No.l LeTel Holbrook
No.2
Lel Cur >nd Holbrook
No.3 Le.el Czar >nd Holbrook

No.4 Lvfl
Czr
>IK)
Holbrook
No.5 Lael Holbrook
Section through Copper Queen Mine, Bisbee, Ariz., showing variable

depth of weathering. (After Douglas, Amer. Inst. Min. Engrs., Trans. XXIX.)
FIG. 152.
Weathering may disguise the true character of an ore body

most effectually. For example, the ore found in the outcrop may
be a gold ore, and mills are sometimes erected and operated for a
period on such ore, without any suspicion that beneath there may
be great bodies of copper or lead sulphides. Such a change has
been found at Bingham, Utah; Butte, Montana; or Mount
Morgan, Australia. The last has been one of the world's greatest
gold mines, but is now producing copper from its lowest levels.
1
Econ. Geol., Ill: 425, 1908.
ECONOMIC GEOLOGY
476
In other cases, the base metals may all have been leached out of the
upper part of the ore body, and too little gold remains in the gossan
make it profitable. Butte, Montana, is a well-known example

of this, for the nearly barren outcrops gave little clew to the great
to
sulphide ore bodies lying below, and which might never have
been discovered but for the presence of another system of closely
associated veins carrying silver.
Weathering or Superficial Alteration
Nearly
(155-158).
all
minerals are attacked by the weathering agents, but the metallic

minerals are more easily and more profoundly affected than the
non-metallic ones.
This weathering process involves both chemical and physical

changes similar to the decay and disintegration of common rocks,
but in ore bodies the great number of minerals involved, including
many
with a metallic base, give
rise to
a large
number
of in-
tricate chemical reactions.
As a
result of weathering worthless minerals
may
be removed,
leaving the weathered part more porous, and this may increase
the richness, because we have a greater quantity of metals per
ton of rock.
The character of the outcrop in non-glaciated areas depends

on the relative resistance to weathering of the ore and wall
rock.
Hard quartz veins, silicified ledges (Plate LVIII, Fig. 2),
or dense fine-grained garnet rock are usually more resistant than
the country rock, and may remain standing in more or less strong
relief.
Pyritic deposits weather more easily usually than the wall
and
hence a depression may be developed.
rock,
A mixture of quartz and pyrite will yield a mass of rusty
honeycombed quartz, or a hard porous limonite, such a mass
being
known
as gossan or iron hat (French, Chapeau de fer; GerSolid sulphide ore bodies also are often
man, Eisener Hut).

capped by a gossan.
'The weathering of
an ore body
is
a comparatively slow process,
so that in glaciated areas, unweathered ore may extend close

to or actually up to the surface, because since the retreat of the
time has been too short to permit much weathering.

Oxidation in general extends to the water level, although
there may be a number of exceptions to this rule. It may hence
ice the
show great variation

from
depth due to this cause alone, but aside

an influence, such as topographic
nature of the rock, whether fissured, porous
in
this other factors exert
conditions, rainfall,
ORE DEPOSITS
477
or dense, kind of ore minerals, climate, etc. Even in the same

deposit oxidation may extend to greater depths in one place than
another (Fig. 152), because of the presence of fissures which permitted local penetration of the surface waters.
of the maximum depth to which weathering
extend in some parts of an ore body the following can be
As examples
may
mentioned
1600 feet
2000
1300
1200
100
400
Bisbee, Ariz
Utah
Bingham, Utah
Tintic,
Tonopah, Xev
Ducktown, Tenn
Butte,
Mont
in places.
As a result of oxygen-bearing surface waters entering the ore

body, chemical changes begin, oxidation and hydration being
important; and these together with other changes, produce
many
soluble compounds.
oxidation of pyrite, for example, gives sulphuric acid,
the latter is active in the formation of ferrous and ferric
The
and
sulphates, of which the last-named
is
important as an oxidizing
agent.
Not
all of
the sulphides appear to be attacked with equal readi-
and the same mineral may show different degrees of resistance under different conditions. That the order of resistance
does not seem to be the same in all cases, is indicated by the
ness,
The second table by Emmons (no),

an interesting manner the changes that have taken place
in the weathering of the copper ores at Ducktown, Tenn.
Whatever the order in which the sulphides succumb to the
attacks of the weathering agents, they all yield, forming new compounds stable under surface conditions, and sometimes of soluble
character, which permits their removal.
Among the compounds found in the oxidized zone are the
first
table on page 478.
shows
in
iron, hematite, manganese oxides, free gold under favorable conditions, silver chloride, silicates, carbonate and
sulphate of lead, and oxidized compounds of zinc and copper.
hydrous oxides of
Tolman
(120) claims
that the zone of weathering can be divided
which beginning at the surface
are:
(1)
of complete oxidation; (2) zone of complete leaching:

zone
of oxide enrichment which is of variable thickness
(3)
and
and
into three subzones,
Zone
lying immediately above the sulphides.
ECONOMIC GEOLOGY
478
The
cap.
represents complete oxidation and includes the iron

shows limonite, hematite, residual silica, and some-
first
It
ORDER OF OXIDATION OF SULPHIDES, ACCORDING TO SEVERAL AUTHORITIES

1
ORE DEPOSITS
479
times residual gold, as well as silver chloride.

copper oxidation products may be present.
Lead, zinc, and

Thp second is
usually somewhat thoroughly leached of its metallic contents, but

the gold and less often silver may extend down into it. The
third may contain partly oxidized minerals, and include native
elements, oxides, carbonates and silicates brought from above.
Some authors do not
agree to this constant zonal division of the
weathered zone.
The reactions that take place in

Reactions of Oxidized Zone.
the oxidized zone are primarily those taking place between the
sulphides, oxygen, water, carbon dioxide and sulphuric acid.
These may be followed by reactions between the products so
formed or between these and other minerals, the result in some
cases being the formation of minerals of stable and slightly
soluble character, which are evidence of weathering reactions.
Some
of the possible reactions follow
= FeSO 4 +S,
FeS 2 +4O
FeS 2 +70+H 2 O = FeSO 4
2 SO 4
= FeSO 4 +SO 2
FeS 2 +6O
+H
Ferrous sulphate, however, oxidizes to
ferric sulphate,
2FeSO 4 +H 2 SO 4 +O = Fe 2 (SO 4 ) 3 +H 2 0.
But the ferric sulphate is not very stable near the surface,
although deeper down this salt together with ferric chloride
and even other ferric salts may remain in solution, and serve as
oxidizing agents..
Both
ferric
and ferrous sulphates
may yield
limonite as follows
6FeSO 4 +30+3H 2 O = 2Fe 2 (SO 4 ) 3 +Fe2 (OH) 6
Fe 2 (S0 4 ) 3 + 6H 2 O = 2Fe (OH) 3 + 3H 2 SO 4

4Fe(OH) 3 =2Fe 2 3 +6H 2 O = 2Fe 2 O 3 -3H 2 O+3H 2 O,
2Fe 2 (SO 4 ) 3 + 9H 2 O = 2Fe 2 O 3 3H 2 O + 6H 2 SO 4
,
As evidence
of the oxidizing effect of ferric sulphate
we have
FeS 2 +Fe 2 (SO 4 ) 3 = 3FeSO 4 +2S and

2S+6Fe 2 (SO 4 ) 3 +8H 2 O = 12FeSO 4 +8H 2 SO 4
Again the
ferric
sulphate
may
break up in the presence of water
as follows:
Fe 2 (S0 4 ) 3 +H 2 O = 2FeS0 4 +H 2 S0 4 +O.
ECONOMIC GEOLOGY
480
the atom of oxygen liberated being free to attack oxidizable substances.
Another important role played by ferrous and ferric salts

as solvents and precipitants of gold (Emmons).
Gold forms no insoluble compound in the oxidized zone,
and it is not soluble in sulphuric acid; nor is it soluble in ferric
sulphate as has been sometimes stated.
is
If gold is in solution as the chloride, it is precipitated by ferrous

sulphate, formed in manner indicated above, but if much manganese oxide is present, the ferrous sulphate is oxidized to ferric
The presence
sulphate, which does not precipitate the gold.
of
manganese oxides therefore favors the dissolving of gold in acid

On meeting a reducsolutions, and it may be carried downward.
ing environment, however, both the gold and manganese are
precipitated.
Copper sulphides
also are subject to oxidizing action, thus:
CuFeS 2 +8O = CuSO 4 +FeS0 4

At
times, however, a reduction
equation
may occur,
as
shown by the next
uSO 4 +2FeS0 4 = Cu+Fe 2 (S0 4 ) 3

The copper sulphate may be
held in the oxidized zone as a
result of the following reactions:
2CuSO 4 +2H 2 Ca(C0 3 )2
= CuCO 3 (CuOH) 2 +3CO 2 +2CaSO 4 +H 2 O,

3CuSO 4 +3H 2 Ca(CO 3 2
- 2CuCO 3 (CuOH) 2 + 3CaSO 4 + 4C0 2 + 2H 2 O,
)
Cu 2 O+H 2 SO 4 = Cu+CuSO4 +H 2 O,
CuS0 4 +H 2 Ca(CO 3 ) 2 +H 4 SiO 4
= CuO-H 4 Si0 4 +CaS0 4 +H 2 0+C0 2
If zinc sulphide is present
unaccompanied by pyrite the reaction
will be:
If, however, pyrite or some other source of Fe 2 (SO 4 ) 3 is present,

then the reactions may be more complicated, as shown by the
following:
1
Wang, Y.
T.,
Amer.
Inst.
Min. Engrs., Bull. Sept., 1915, 1959.
ORE DEPOSITS
481
3ZnSO4+3Na 2 CO 3 +4H 2 O =
= ZnC0 3 -2Zn(OH) 2 +3Na 2 SO4+2H 2 C0 3
= CaC0 3 +ZnC0 3 +H 2 S04,
= ZnCO 3 +Na 2 SO4+H 2 CO 3
Downward
In
many
Secondary
ore bodies there
Enrichment (106-122).
Sulphide
is found below the oxidized zone a
second one in which the ore
may
be richer than that above or
below it. This zone, known as the secondary sulphide zone, has
been enriched by the deposition of secondary sulphides, is of
variable thickness
and
richness,
and represents the
results of
important processes which have often converted a non-workable

1
ore deposit into a workable one.
The process of downward sulphide enrichment briefly stated
Ore minerals in the zone of weathering become conis as follows
:
verted into soluble compounds (sulphates chiefly), as explained

above, and these, on being carried down below the water level,
come
in contact with unaltered sulphides or other reducing agents
1
There is likely to be some confusion if, in the future different investigators
do not adhere to uniformity in usage of the terms primary and secondary. In this
book, the term secondary sulphide enrichment is applied to the precipitation of
sulphides below the oxidized zone, from meteoric waters, penetrating the ore body
from above, and taking metallic salts from the oxidized to the unoxidized zone.
Emmons (HO) applies the term primary to al 1 ore bodies whose chemical and
mineral composition have remained essentially unchanged by superficial agencies
A secondary ore he classes as one that has been
since the ores were Deposited.
altered by superficial agencies.
Tolman (120) classifies the minerals of an ore deposit into original minerals of
the rock; primary minerals introduced by vapors and waters of deep-seated or
igneous origin, and secondary minerals contributed by descending surface waters.
Rogers (117) would apply the name secondary to a mineral formed at the
expense, or by the replacement of, an earlier formed mineral. He then uses the
term upward secondary enrichment to sulphides deposited from rising solutions,
and downward secondary enrichment to those deposited from descending solutions.
These two terms correspond respectively to Ransome's hypogene and supergene.*
In the case of copper ores which Rogers has studied he states that the criteria
of downward chalcocite enrichment may be summarized as: (1) comparatively
regular replacement along anastomosing channels; (2) the presence of quartz
veinlets related to chalcocite deposition; (3) the association of melaconite with
Criteria of upward chalcocite enrichment may be
chalcocite along veinlets.
summarized as follows: (1) Irregular intricate replacements; (2) the presence
of so-called graphic intergrowths of bornite and chalcocite; and (3) presence of
sericite related to chalcocite deposition.
Further study will be required to see
whether these criteria hold.
* U.
S. Geol. Surv., Bull. 540; 52.
1914.
ECONOMIC GEOLOGY
482
which reduce them again to insoluble sulphides. Thus they

bring about a secondaiy enrichment of the ore body.
Important as this process is, it was not clearly recognized until
a comparatively late date, when the writings of De Launay l in
France, and of S. F. Emmons (108), Weed (122), and Van Hise
(88), in the United States did much to increase our knowledge of
the subject.
All ore minerals are not subject to the process of secondary
enrichment as outlined above, it being most often seen in ores of
copper, gold, and silver, and to lesser extent in lead and zinc.
Secondary-sulphide enrichment like weathering may be affected

These include
of, and sometimes the same factors.
by a number
climate,
locality,
Warm
altitude,
permeability,
relief,
geologic
history of the
chemical and mineral composition.

climates favor chemical reactions, and cold climates not only
retard them, but freezing temperatures prevent solution. Secondary-enrichment zones are rare in north latitudes as compared with southern ones.
If formed in the past under different climatic conditions they may have been
removed by glaciation.
Rainfall in abundance may be favorable, because of its stimulating effect
on groundwater
circulation,
but scarcity of
rainfall
does not preclude the
possibility of finding secondary ores, as a moderate supply of water acting

through a long period of time may have yielded favorable results.
High altitude may act unfavorably because of rapid erosion and low
temperatures, but under favorable conditions enrichment may occur.
Strong relief favors deep and rapid underground circulation and hence
cause relatively deep enrichment, while in a base leveled area the circulation will be sluggish, and the waters will not descend far before losing the
may
metals dissolved higher up.
Slow erosion means a longer exposure of outcrop, hence long weathering

leaching, but if the process continues there may be a downward
migration of both the oxidized and secondary enrichment zone; the products
of secondary enrichment may therefore be derived from portions of the ore
body long since removed.
Permeability is an essential factor, because unless the solutions can penetrate the unweathered part of the ore body, secondary enrichment can not
occur.
The permeability may be due to original porosity of the ore, or to
fractures caused by post-mineral movements.
Comparatively small openings
sometimes appear sufficient for permeation.
and thorough
An
is the past topography, for the enrichplace when physiographic conditions were quite difare now, and hence the zone of secondary sulphides
important point to consider
ment may have taken

ferent from what they
shows no rational relationship

1
to the present land surface.
Les variations des filons metalliferes en profundeur, Revue g6n6rale des

Sciences, etc., Apr. 30, 1900, No. 8.
PLATE XLII.
tains,
(cc.)
Photomicographs of polished specimens of ore from Burro MounN. Mex., showing progressive replacement of pyrite (p) by chalcocite
X40.
(R. E. Somers, photo.')
(483)
ECONOMIC GEOLOGY
484
Under normal conditions the secondary sulphides would be deposited

below water level, but subsequent changes in the lattei, too rapid for the
chemical changes to keep pace with,
extending above the water level.
may
result in secondary sulphides
Downward Secondary Sulphide Enrichment
Criteria of
(ill, 116,
geologic, mineralogic and textural.

one alone will not necessarily afford conclusive evidence.
These
117).
maybe
geologic criteria include suggestive surface conditions
Any
The
such as a
leached ferruginous gossan, underlain by chalcocite and this in

turn by cupriferous pyrite. Or the weathered zone may show
argentiferous galena, more or less altered to cerussite, with
deeper
and
down
pyrite.
the appearance in increasing quantities of sphalerite

Assay maps of an ore body showing a lean zone above,
passing downward into one of relatively greater richness, and

this in turn into a much poorer zone, are also suggestive.
It is difficult to name any mineral as distinctively characteristic
of secondary enrichment.
Even chalcocite which at one time was
regarded as typical of this process is now known to be formed by
primary deposition.
Textural criteria
may
be of value.
Thus we
find veinlets of
rich ore in leaner material; the irregular replacement of one minevidence of solution followed
eral by another (Plate XLII);
by deposition of fresh material; or grains of primary sulphide

surrounded by secondary ones, as chalcocite surrounding pyrite.
No one of these, however, should be used alone.
Chemistry of Secondary Sulphide Enrichment (110, 119, 120).
The exact equations of secondary sulphide enrichment are not
always known.
those that
may
Reference has already been made to some of

occur in the zone of weathering, resulting in the
formation of soluble sulphates, chlorides or bicarbonates.

Precipitation below the water level may be due to (1) Reduc:
tion of sulphates to metallic sulphides by carbonaceous matter;

(2) Reduction by hydrogen sulphide; and (3) Reaction of salts
with sulphides.
With regard to the precipitation of sulphates by sulphides, it

has been found that this agrees somewhat closely with Schurmann's law which arranges the metallic sulphides in a series, any
member
of which will be precipitated at the expense of any sulin the series. 1

lower
His series was Hg, Ag, Cu, Bi, Cd,
phide
Mn.
According to this pyrite for example
Pb, Zn, Ni, Co, Fe,
1
Liebig's Ann. der Chemie,
CCXLIX:
326, 1888.
ORE DEPOSITS
would
485
above
precipitate, copper, lead, zinc or others in the series
we had descending
solutions carrying copper, lead

and silver, the order of precipitation of the sulphides of these
would be silver, copper and lead sulphides.
Again
it.
if
The order of precipitation mentioned above may not hold

under all conditions, for as mentioned by Tolman (120), on
account of mass action, a strong solution of a metallic salt,
may cause a precipitate at the expense of a member of the series
higher up.
Reactions of Secondary Sulphide Deposition (110, 120). Various
reactions have been written to explain the precipitation of metallic
sulphides in the zone of secondary enrichment. It is probable
that some of them do not always state the case exactly, and that
the change instead of being a simple and direct one may involve
several intermediate steps.
Thus, for example, chalcocite is
found as a secondary mineral, precipitated by pyrite, but careful
work by Graton and Murdock (ill), corroborated by experimental work performed in the Carnegie Geophysical Laboratory
at Washington 1 has shown that the change from pyrite to chalcocite is not a direct one, but that there may be intermediate
stages so that the order of formation in
some
cases at least
is:
Bornite-+Covellite >Chalcocite. These

>Chalcopyrite
changes result from the action of copper sulphate solutions on
Pyrite
and at low temperatures are probably exceedingly slow.

For copper some of the enrichment zone reactions published are:
sulphides,
2CuSO 4 +2FeS 2 = Cu 2 S+2FeSO 4 +3S, or

14CuSO 4 + 5FeS 2 + 12H 2 O = 7Cu 2 S + 5FeSO 4 + 12H 2 SO 4
4CuSO 4 +FeS 2 +3SO 2 +6H 2 O = 2Cu 2 S+FeSO 4 +6H 2 SO 4
CuSO 4 +CuFeS 2 = 2CuS+FeSO 4 or

2CuSO 4 +CuFeS 2 +SO 2 +2H 2 O - Cu 2 S+CuS+FeSO 4 +2H 2 SO4,
CuSO 4 +2FeS 2 +2O = CuFeS 2 -}-FeSO4 +SO 2
CuSO 4 +ZnS = CuS+ZnSO4
CuSO 4 +H2 S = CuS+H 2 SQ4
,
may be 2
ZnSO4 +FeS 2 = ZnS+FeSO 4 +S, or
2ZnSO 4 + FeS 2 + H 2 O = 2ZnS + FeSO4 + H 2 SO 4 +
For zinc the equations
or
Day, Min. and Sci. Pr., CX: 841, 1915.

2
For cases of secondary sphalerite see Blow, Anier. Inst. Min. Engrs., Trans.,
XVIII: 172, 1890; Graton, TJ. S. G. S., Bull. 430, 71: 1910; Ransome, Ibid.,
Prof. Pap. 75: 169,1911; Finlayson, Econ. Geol., V: 417,1910.
1
ECONOMIC GEOLOGY
486
7ZnSO 4 +4FeS 2 +4H 2

For lead we have
= 7ZnS+4FeS0 4 +4H 2 S0 4
PbSO 4 + FeS 2 + O 2 = 9PbS + FeSO 4 + S0 2

PbS0 4 + ZnS = PbS + ZnS0 4
It is difficult to distinguish secondary lead and zinc minerals

from primary ones, because they are the same in each case, and
while they no doubt occur, few well-defined cases have been de-
scribed. 1
Secondary silver sulphides undoubtedly occur. The compounds said by Ransome to be more often secondary than primary
are stephanite, polybasite, argentite, pyrargyrite and proustite.
Hydrothermal Alteration
(13,
21,
103).-
The hot ascending
solutions of varying composition often bring about a most profound alteration of the rocks which they traverse, extracting it
may be, certain elements and adding others. Indeed in some
cases the alteration
no resemblance to
so extensive that the rock affected bears
is
its
former
self.
usually most intensive along the fissures which

guided the solution, but if the rock is extensively fractured it
may be affected over a large area.
Alteration
is
The changes produced
will
not only vary with the composition
of the solution, but also with the temperature
some cases
similar changes
of non-magmatic character.
in
The types
of
may
and pressure, and
be wrought by cold solutions
hydrothermal alteration which are well recognized
are propylitiaztion, sericitization, silitification, alunitization
and
greisenizat-ion.
Two
sometimes occur in the same rock.

This is a common type of alteration,
which affects chiefly andesites and basalts, but rarely rhyolites.
It results in a change of the silicates to abundant chlorite, and
Carbonates are likewise
pyrite, as well as epidote in some cases.
formed, and in some cases there may also be sericite. The rocks
so changed are usually of a greenish-gray color, but may preserve
of these
may
Propylitization
(21, 103).-
their original texture.
The
process
may
involve extraction of
soda and potash, as well as silica, and even lime, and magnesia
unless carbonates are formed, while the additions consist chiefly
of sulphur and water.
1
See Finlayson, Econ. Geol., V: 421, 1910; Weed, Amer. Inst. Min. Engrs.,
424,1901; Irving and Bancroft, U. S. G. S., Bull. 478: 97,1911.
XXX:
ORE DEPOSITS
is
487
Propylitization is probably a somewhat shallow process, and

a common accompaniment of some western gold and silver
It is found in the rocks bordering the veins at Virginia

City and Tonopah, Nev., Cripple Creek, Colo., and other places.
This is a common type of hydrothermal alteraSericitization.
tion, which is often seen near veins, but may pass outward into
veins.
The
propylitic alteration.
rocks so altered are white or light
yellow in color, and the mass often appears clay-like. Indeed

sericite masses are sometimes mistaken for kaolin, and it is diffi-
from kaolinite, under the microscope.

Sericitization involves a loss of soda and a gain of potash.
cult to distinguish sericite
may be reduced or increased in amount, and carbonates

be formed, while pyrite is usually added. The resultant
product is a fine-grained mixture of sericite, adularia and pyrite,
Silica
may
with sometimes calcite and quartz, the first-named of these being

developed from both quartz and feldspar. Close to the vein,
silicification
sometimes overshadows
The
Sericitization.
latter
take place in veins of both shallow and intermediate

depth; moreover although chlorite may be developed first,
sericite may crowd it out later (Butte, Mont.).
process
may
Silicification.
This
is
also a
common form
of alteration associ-
ated with the deposition of ores, being more often noticed in acid
than in basic rocks. Rhyolites may often show it, both the
groundmass and phenocrysts being affected. At Goldfield, Nev.,
ledges so prominently associated with the ore bodies
are formed by the alteration of andesite (Plate LXVIII, Fig. 2).
The quartz thus formed is of cherty character, but the original
the
silicified
structure of the rock
may be clearly preserved.

may also be silicified, as
other calcareous rocks
Limestones and
in
some contact
metamorphic deposits. (See Bisbee and Miami, Arizona.)

In some cases silicification may be brought about by meteoric
waters (southwest Missouri zinc district).
Alunitization.
This type of alteration, which
common
was
first
one,
feldspars have been
is
not a very
noticed at Goldfield, Nev., where the
somewhat extensively altered to alunite.

that
takes
place at shallow depths, and is thought
change
to be due to the action of descending sulphuric waters, meeting
It is a
ascending alkaline ones.
The
alunite at Goldfield occurs not only as a massive crystalline
constituent of the altered rocks, but also intergrown with pyrite,

gold, tellurides, and other minerals of the ore.
ECONOMIC GEOLOGY
488
number
Alunitization has since been noticed at a
western
localities.
Greisenization.
of other
(See references under Potash.)

The granite walls of many tin veins
show a
strong and characteristic alteration, the feldspar and muscovite
being attacked by water vapors carrying fluorine and boric acid,

resulting in the development of a mass of quartz, topaz, tourmaline and lepidolite, to which the name greisen is applied.
Cassiterite
may also
be present in the altered w all rock.

r
The terms rich and poor, as applied to ores,

Value of Ores.
are used with great frequency, although most indefinite and often
Under very favorable conditions it is possible to
meaningless.
work an ore of given value at one locality, while if found
under other less favorable conditions at another point it might be
almost worthless.
Those who have not given special study to ore deposits often
fail to realize that in the majority of ores the percentage of metal
contained in the ore falls considerably below the theoretic percentage of the metallic contents in the ore-bearing minerals, due
profitably
of course to the presence of a greater or less quantity of gangue

minerals which tend to dilute the metallic values of the vein.
Many
and
low-grade lead ores are profitably mined because their gold

more than pay the cost of metallurgical treat-
silver contents
ment.
In
many
cases the metallic contents of the ore
by mechanical concentration or by roasting

phides), or both, before the ore
Allowable
Minimum
of Metal in
is
is
increased
(in the case of sul-
smelted.
an Ore
(52).
Iron ores are of
little
value, wherever they may be located, unless they contain at least 30 per
cent of iron when charged into the furnace.
Copper has an average minimum of about 2 per cent, but the Lake
Superior ores, because of their peculiar characteristics, can be operated on a
lower percentage. Many of the western disseminated copper sulphides,
which are worked on such an extensive scale, do not average much over
2 per cent. In the case of these low-grade ores the metallic contents are
raised by mechanical concentration or roasting, or both, before entering the
furnace.
Lead.
carrying as
I
In southeastern Missouri lead ores are profitably mined when

little as 5 to 10 per cent metal, but the concentration raises the
ercentage up to 65 or 70 per cent.

Zinc ores on entering the furnace should have a
minimum of 25 to 30 per
cent zinc, but the contents are sometimes raised to 60 or more per cent by
concentration, the concentrates being sold on a percentage basis. Some of
the Missouri zinc ores as mined run as low as 3 per cent zinc.
Gold and Silver. The metallic contents of these ores are expressed, not
ORE DEPOSITS
489
but in troy ounces per ton, a troy ounce in a ton being -^^
per cent. The market value of silver is, in round numbers, 50-60 cents per
ounce, while gold in round numbers is figured at $20 per ounce.
Silver rarely occurs alone, and the ore may be treated primarily for its
in percentages,
associated lead
and copper.
In the base ores there should be enough silver to yield a minimum of $5

or 10 ounces in the resulting ton of copper, to make its extraction profitable.
If now in a 5 per cent copper ore 20 tons of ore are concentrated to 1 ton
of pig copper (or 21 tons, allowing for losses), it follows that we need 10
ounces of silver, in 21 tons of ore, or a minimum of f ounce silver per ton,
or
ô
P er cent.
Under favorable conditions gold can be extracted down
to
ounce per
ton or g^Vo P er cent. It usually runs from to 1 ounce.
ounce gold may be an
In some copper or lead ores the saving of even
In gravels, a gold content of as low as 7 to 10 cents per cubic yard
object.
(wo to 3^75- ounce) may be saved.
For this metal the crude ore commonly ranges from 1.5 to 3 per
Tin.
cent, but by concentration it can be raised to 70 per cent.
Nickel should reach 2 to 5 per cent in the crude ore.
Owing to the scarcity of this metal, few figures aie availbut in Russia placers are worked which carry $ ounce per cubic yard,
which is the equivalent of -^ ounce per ton or 5.5 hundred- thousandth perPlatinum.
able,
cent.
Manganese to be considered of commercial grade must contain at least

35 per cent manganese and otherwise conform to the specifications of the
trade in which they are used.
Chromium ore should carry 40 per cent of the metal.
Classification of
Ore Deposits.
Many
attempts have been
made
to develop a suitable classification of ore deposits, and many

schemes have been suggested (46). These are usually based either
en form, mineral contents, or mode of origin. The first is perhaps

the most practical from the miner's standpoint, the second is undesirable because several kinds of ore may often be found in the
same ore body, while the third is the most scientific, and is of
value to the mining geologist and engineer.
Those desiring to look into this phase of the subject in more
detail are referred to the bibliography at the end of this chapter,
especially the papers
and Vogt
Two
by Kemp
(46),
Posepny
(68),
Van Hise
(2),
(13).
classifications are given here, viz., those of
and W. Lindgren.
Both are based
characters, but the second goes a

to indicate
more
W. H. Weed
on genetic
and attempts
in part at least
little
farther,
definitely the physical conditions of deposition.
ECONOMIC GEOLOGY
490
CLASSIFICATION OF
A. Igneous,
(a)
magmatic segregation.
Siliceous.
1.
2.
3.
(6)
ORE DEPOSITS (AFTER WEED)
Masses, Aplitic masses. Ehrenberg, Shartash.

Dikes, Beresite or Aplite. Berezovsk.
Quartz veins. Alaska, Randsburg, Black Hills.
Basic.
Peripheral masses.
Copper, iron, nickel.
(Sudbury, Ont.)
Dikes, titaniferous iron. Adirondacks, Wyoming.
B. Igneous emanations.
Deposits formed by gases above or near
1.
2.
the critical point,

(a)
365
C. and 200 atmospheres for
O.
1.
Deposits confined to contact. Magnetite deposits (Hanover,

N. Mex.), chalcopyrite deposits, Kristiania type, gold ores,
2.
Deposits impregnating and replacing beds of contact zone.

Chalcopyrite deposits, pyrrhotite ores, magnetite ores, Cananea type, gold tellurium ores, Elkhorn type, arsenopyrite
Bannock,
ores,
(b)
e.g.
Contact-metamorphic deposits.
Ido., type.
Similkameen type.
Veins closely allied to magmatic veins and to Division D.

1. Cassiterite.
Cornwall.
2. Tourmaline copper.
Sonora.
3.
Tourmaline gold.
4.
Augite copper,
C. Fumarolic deposits.
etc.
Helena, Mont., Minas Geraes, etc.
Tuscany.
No commercial imporetc., in clefts in lava.

Copper, iron, etc.
D. Gas-aqueous or pneumato-hydato-genetic deposits, igneous emanations, or primitive water mingled with ground water.
(a)
Metallic oxides,
tance.
(a)
Filling deposits.
1. Fissure veins.
Impregnation of porous rock.

Cementation deposits of breccia.
Replacement deposits.
1. Propylitic.
Comstock.
2. Sericitic kaolinic, calcitic, Copper
thai.
De Lamar, Ido.
2.
3.
(b)
3.
4.
5.
silver, Silver lead.
Silicic dolomitic, silver lead,
Aspen.
Cinnabar, California.
Sideritic silver lead.
Co3ur d'Alene, Slocan,
Silicic calcitic.
Wood
Biotitic gold copper.

Rossland, Brit. Col.
7. Fluoric gold tellurium.
Cripple Creek, Colo.
6.
8.
Zeolitic.
Michigan copper
ores.
Structure Types of Above
Fissure veins.
(San Juan, Colo.)
Volcanic stocks, Xagyag. Cripple Creek.
Contact chimneys. Judith.
River.
Glaus-
ORE DEPOSITS
491
Dike replacements and impregnations.

Bedding or contact planes. Mercur.
Axes of folds, synclinal basins, anticlinal saddles.
Bendigo,
Elkhorn.
E. Meteoric waters.
(a)
2.
(Wisconsin lead and zinc.)

Replacements. Iron ores, Michigan
3.
Residual.
1.
(6)
(Surface derived.)
Underground.
Veins.
Gossan iron
ores,
lead, zinc.
manganese deposits.
(Virginia.)
Surficial.
1.
Chemical.
Bog
iron ores, sinters.
Some bedded
iron ores, etc.
(Clinton ore.)
2. Mechanical.
Gold and tin placers.
Metamorphie deposits. Ores concentrated
metamorphism, dynamo or regional.
F.
CLASSIFICATION OP
from
rocks
older
by
ORE DEPOSITS (AFTER LINDGREN)
I.
Deposits produced by mechanical processes of concentration.

ture and pressure moderate.)
Ex. Placers of gold, platinum, etc.
(Tempera-
II.
Deposits produced by chemical processes of concentration.
(Tempera-
ture
and pressure vary between wide
limits.)
A. In bodies of surface water.

1.
By
interaction of solutions:
2.
Temp.,
Anorganic reactions. Clinton iron ore.

b. Organic reactions.
Ex. Bog iron ore.
By evaporation of solvents. (No metallic examples).
a.
0-70.
Pressure
moderate.
B. In bodies of rocks.
1.
By
concentration of substances contained in the geological
body
a.
itself.
Concentration by rock decay and residual

weathering near surface. Ex. Residual
iron
6.
and manganese
Concentration by ground water of deeper

Ex. Lake Superior
circulation.
ironj
ores
c.
ores.
o-100
p
Concentration by
metamorphism.
some schists?
mo(jerate.
o-100
p
moderate.
Temp, up
dynamic and regional

Ex.
Fahlbands in
j
,QQ
O
"
p
,
50-300.
Pressure
!Temp.,
moderate.
ECONOMIC GEOLOGY
492
2.
Concentration effected by introduction of substances foreign

to the rock.
a.
Origin independent of igneous activity.

f
By
circulating atmospheric waters at

moderate or slight depth. Ex. Miss,
valley lead
b.
and
zinc ores.
Temp.,
.
IAQQ
p
moderate
Origin dependent upon the eruption of igneous rocks.

a. By hot ascending waters of uncertain origin, but
charged with igneous emanations.

f
1.
Deposition and concentration at

Ex. Goldfield,
slight depth.
Nev.
Temp.,
50-
150.
j
Pressure
moderate.
2.

Ex.
intermediate depth.
Leadville,
Colo.;
Cobalt,
Ont.
Temp.,
150300.
Pressure
high.
3.

great depth or at high tem-
300-
perature and pressure.

Ex. Tin veins; Ontario quartz
Pressure
veins.
b.
By
direct igneous emanations.
Temp.,
500
very high.
ORE DEPOSITS
493
of igneous activity.
This process has been active, during a
of periods in the past, as shown by the geologic records,
available data
for
number
and the
North America have been summarized by
Lindgren as follows (62)

Pre-Cambrian Period.
The pre-Cambrian
rocks,
which under-
a number of extensive areas in the United States, include not

only metamorphosed schists and gneisses, but also various types
lie
of intrusives, the characteristic metals being iron, copper, nickel,
Lead and zinc are less

gold, and silver.
in the later periods, while quicksilver and
The
ilmenites
and magnetites
abundant than they are

antimony are rare.
of the eastern states are chiefly
Lake Superior are partly

igneous and partly sedimentary, but subsequently oxidized and
concentrated by surface waters, a process which is believed to have
gone on in pre-Cambrian times. The copper and nickel ores are
of igneous origin, while the hematites of
associated with basic igneous rocks, some of these, as in Michigan,

being of effusive nature. This copper concentration Lindgren
suggests
close of
age are
must have gone on in pre-Cambrian times, following the

Keeweenawan (Algonkian) volcanic activity. Of similar
the cobalt-silver veins of Ontario. The auriferous-quartz
veins of the southern states, whose deposition followed that of

granitic intrusions in schists, are also to be placed here, although
some writers would date them later.
In the Cordilleran region the pre-Cambrian was productive of

gold and copper deposits, which are found at many points from
South Dakota and Wyoming to Arizona. These gold ores are
usually lenticular quartz veins in schists, associated with such
gangue minerals as tourmaline, garnet, etc. The copper ores often
contain chalcopyrite, and form veins or irregular masses, which

are probably of magmatic origin, and have been modified by
dynamo-metamorphism. Sphalerite may accompany the chalcopyrite, but lead
is almost entirely wanting.

In Ontario a careful study of the pre-Cambrian rocks by Miller
and Knight l (66) has shown the possibility of recognizing at
least five metallogenetic epochs as follows
1. Grenville.
Epoch of extensive deposition of "iron formation," as a chemical precipitate among other sediments.
:
2.
tion
3.
1
Timiskanian.
"
of
minor deposition
of
"
iron forma-
as a chemical precipitate.
Algoman.
For
Epoch
classification
Epoch
following granite intrusions, of gold at
used here, see Geol. Soc. Amer., Bull.
XXVI:
87, 1915.
ECONOMIC GEOLOGY
494
Porcupine and other loca

ceding
granite
ities,
intrusions,
Timiskanian age, gave
and
basic
of auriferous mispickel.
intrusions
rise to nickel, titaniferou?
erous magnetites and chromite.

4.
Animikean.
of
Epoch
of deposition of
"
Pre-
probable
and
postnon-titanif-
iron formation
"
as a
chemical precipitate.
Keweenawan.
Epoch following basic intrusions of: a. Silnickel
and
arsenic at Cobalt and elsewhere; b. Nickel
ver, cobalt,
and copper at Sudbury and copper elsehwere.
Paleozoic.
During this time a number of granitic intrusions
occurred from New York and New England northward to Quebec
and Nova Scotia, and these were accompanied by the formation
of some gold-quartz veins; but little metallization occurred in the
West during this period.
5.
Two
periods of iron-ore formation occurred during Paleozoic

One of these was in the Silurian, when the per-
time in the East.
sistent beds of low-grade Clinton hematite were formed; the other

was during the Carboniferous, when the layers of carbonate blackband ores were deposited.
Mesozoic.
During the Triassic, small deposits of copper and
iron ores were formed in the eastern states, along the contact of the
trap sheets and sedimentary rocks. The deposits were in part
veins and in part of contact-metamorphic character.
In the West important accumulations of ores were beginning,
began a series of eruptions which

continued through the Jurassic, the products of these being basic
The metallavas which were extruded from California to Alaska.
for during the Triassic there
accompanying or following these yielded copper deposits,

which include some of those found in California, British Columbia,
and those of the Copper River region in Alaska.
Another important metallization epoch followed the intrusion
of the great early Cretaceous quartz-monzonite or grano-diorite
lization
batholiths of the Pacific coast.
These injections were of vast extent, one batholith extending

through California, and another from Washington up through
British Columbia to Alaska, while other smaller masses occur in
several of the western states.
These intrusions were followed by
intense metallization, mineral deposits being formed in abundance
around the margin of the batholiths, as in the gold belt of California. Gold was the chief metal formed, with copper next. Along
the Pacific coast, where there is little limestone in the intruded
ORE DEPOSITS
495
sediments, lead is rarely found, but in the interior (Nevada and

Idaho) where limestones were present, lead and zinc both occur.
Silver is everywhere present, but is rarely important unless associated with lead; arsenic and antimony are rare; and mercury is
wanting in commercial quantities.
About this time, perhaps a little earlier, or
Early Tertiary.
a little later, important concentrations of lead and zinc took place
in the Mississippi Valley, but they appear to have been independent of igneous intrusions, and are thought by most geologists to
represent the work of surface waters, the ultimate source of the

metals being the pre-Cambrian rocks.
At the close of the Cretaceous violent outbursts began along
the eastern margin of the Cordilleran region, the magmas being
and laccolithic form.

Columbia through Montana, Colorado,
of intermediate character
British
eastern Arizona
down
They occur from
New
Mexico, and
into Mexico.
There ensued then another or third epoch of Cordilleran metallization, during which many contact-metamorphic deposits and
Gold and
veins were formed around the margins of the laccoliths.
silver are the characteristic metals, with abundant lead and zinc,
The latter may also
especially where the intrusions cut limestones.
show copper and iron along the contact. Arsenic and antimony
are more common than they were in the earlier epochs, but mercury
is still rare.
Late Tertiary.
After a period of mountain-making disturbances,

warping, and dislocations, there were extruded a series of
lava flows which spread over a large area in the far West, and are
uplift,
prominent in California, Washington, Oregon, Idaho, Colorado,

Utah, Nevada, New Mexico, and Arizona. Andesites and rhyolites predominate.
This was accompanied by a fifth metallization,
whose characteristic metals are gold and silver, forming deposits
often of great richness lead and zinc are not abundant, except
in limestone, and neither is copper.
Tellurium and antimony are;
not that they are absent in older metallizations, but the tellurium
seems to be especially characteristic of this epoch. The metallic
deposits seem to be somewhat restricted, occurring mainly near
;
the foci of igneous activity.

Post-Pliocene.
There came
finally
an epoch of metallization
and
at a late date, restricted, however, to the Pacific coast line,

characterized by the mercury deposits of the Pacific coast belt.
Cretaceous or Later Copper Epochs.
These, being of wide time
ECONOMIC GEOLOGY
496
range, cannot be included in the previous classes. They represent

disseminations of copper in sandstones, shales or conglomerates,
and carry in most cases primary chalcocite with a little silver.
The
Summary.
following table of Lindgren summarizes the
conditions for the western states:
PRINCIPAL ROCKS
ASSOCIATED \VITH
DEPOSITS
PRINCIPAL
METALS
1.
Deposits of the pre-Cam,
2.
Deposits
of
4.
epoch
the
5.
7.
Copper
Gold
....
.
epoch
Deposits
of
Gold, silver
gabbro
Basalt, diabase,
gabbro
Granodiorite,
Granodiorite,
quartz-monzonite,
Copper, lead, zinc
....
the
Granites,
diorites,
{'quartz-monzonite
Deposits of the late Tertiary
6.
early
.
Deposits of the early Tertiary epoch
Deposits of the late Mesozoic
Mesozoic epoch
3.
,,
Gold and copper
brian period
monzonite
Gold, silver
J
{
Andesite
Rhyolite,
Post-
Cretaceous or later concentrations in sedimen-
Quicksilver
Basalt
Copper
Sandstone, shale,
conglomerate
tary rocks
Metallographic Study of Ores (14). Owing to the opaque

character of most ore minerals these cannot be examined in thin
sections
by transmitted
light,
as
is
done with
non-metallic
mineral?.
Another method of study has therefore been developed in recent

and consists in examining polished surfaces of the ore under
the microscope by reflected light. By this means the relation-
years,
ships of the different metallic minerals in the ore can be quite

satisfactorily studied, and differentiated by means of their color,
microchemical
tests, etc.
Plate XLII, shows a series of ore speci-
mens examined and photographed in the manner described above.

This method of etudy has been most helpful in studying genetic
problem?, secondary enrichment processes,
etc.
ORE DEPOSITS
497
REFERENCES ON ORE DEPOSITS

Bain and Others, Types of Ore Deposits. San FranBeck, Lehre von den Erzlagerstatten. Berlin, 3d ed.,
1909. Translation by Weed. New York, 1909. 3. Berg, Mikroskopische
Untersuchung der Erzlagerstatten. Berlin, 1915. 4. Bergeat, Die
Leipzig, 1904. 5. Clarke, U. S. Geol. Surv., Bull.
Erzlagerstatten.
616:626,1916. 6. v. Cotta, Die Lehre von den Erzlagerstatten. Frei-
GENERAL WORKS.
cisco, 1911.
1.
2.
Geology. New York, 1912.

Traite des Gites Mine'raux et Metalliferes.
New York, 1912.
9. Gunther, Exarr.ination of Piospects.
Paris, 1893.
New York, 1909. 11.
10. Hayes, Handbook for Field Geologists.
berg,
8.
1859.
Fuchs
et
7. Farrell,
Practical Field
De Launay,
New York, 1906.

of United States and Canada.
Krusch. Die Untersuchung und Bewertung von Erzlagerstatten.
New York, 1913. 14.
13. Lindgren, Mineral Deposits.
Stuttgart.
Murdock, Microscopic Examination of Opaque Minerals. New York,
1916. 15. Parks, A Textbook of Mining Geology.
London, 1914. 15a.
Posepny, Amer. Inst. Ming. Engrs., Trans., XXIII: 197, 1894. (GenKemp, Ore Deposits
12.
16. Phillips, Treatise on Ore Deposits.

London,
2d edition rewritten and enlarged by Henry Louis, 1896. 17.
Thomas and MacAlister, The Geology of Ore Deposits, London, 1909.
18. Sandberger, Untersuchungen uber Erzgange.
Wiesbaden, 1882.
esis of ore deposits.)
1884;
Geology Applied to Mining. New York, 1904. 20. Van Hise,

Treatise on Metamorphism, U. S. Geol. Surv., Mon. XLVII, 1905.
21. Vogt, Krusch and Beyschlag, Die Lagerstatten der Nutzbaren
!
19. Spurr,
Mineralien und Gesteine.
London, 1914.
Translation by Truscott,
Stuttgart, 1909.
Phil22. WTiitney, Metallic Wealth of United States.
adelphia, 1854.
Papers of Special Character

CLASSIFICATIONS. 23. For a statement of the many proposed see Refs. 2, 11,
13, 21, above.
CONTACT-METAMORPHIC DEPOSITS. 24. Barrell, A. J. S., XIII: 279, 1902.
Pap. 57, 1907. (Marysville, Mont.)

Min. Engrs., Trans., XXXVI: 626, 1906.
(Washington Camp, Ariz.) 27. Kemp, Econ. Geol., II: 1, 1907.
28. Kemp, Min. and Sci. Pr., XCII: 220,
(Limestone contacts.)
29. Klockmann, Zeitschr. prak. Geol., XII:
1906.
(Garnet zones.)
25. Barrell,
26. Crosby,
U.
S. Geol. Surv., Prof.
Amer.
Inst.
30. Lawson, Univ. Calif Pub'ns, Geology, VIII: 219, 1914.

1904.
(Meteoric waters as agents in contact met'm.) 31. Leith, Amer. Inst.
73,
Min. Engrs., Trans., XLVIII: 209, 1915, and Econ. Geol., IX: 292,
1914.
(Limestone crystallization at igneous contacts.) 32. Lindgren,
Amer. Inst. Min. Engrs., XXXI: 226, 1902; also U. S. Geol. Surv.,
33. Lindgren, Ibid., XLVIII: 201, 1915; also
Prof. Pap. 43, 1905.
Econ. Geol., IX: 283, 1914. 34. Prescott, Econ. Geol., X: 55, 1915.
36. Uglow, Econ.
35. Stutzer, Zeitschr. prak. Geol., XVII: 145, 1909.
(Emphasizes segn. of elements in
Geol., VIII: 19, and 215, 1913.
Discussions by Stewart and Kemp, Econ. Geol., VIII: 500 and
rock.)
597, 1913.
ECONOMIC GEOLOGY
498
EMANATIONS
37. Brun,
(GASEOUS).
Recherches
sur
L'Exhalaison
Vol-
Geneva and Paris, 1911. 38. Chamberlin, R. T., Jour. Geol.,

XVII: 534, 1909 and Carnegie Inst. Wash., Pub. 106, 1908. 39. Day
and Shepherd, Geol. Soc. Amer., Bull., XXIV: 573, 1913. 40. Lincoln,
canique.
Econ. Geol., II: 258, 1907.

FAULTS. 41. Ransome, Econ. Geol.,
Bull.,
XX:
171, 1910.
I: 777, 1906.
(Geometry
42. Reid, Geol. Soc.
Amer.,
43. Reid, Davis, Law(Report of Committee on
of faults.)
son and Ransome, Ibid., XXIV: 163, 1913.

44. Spurr, U. S. Geol. Surv., Prof. Pap. 42: 144,
fault nomenclature.)
1905.
46.
(Tonopah.) 45. Tolman, Econ. Geol., II:
506, 1907.
Tolman, Min. and Sci. Pr., CII: 810 and GUI: 128,1911. (Graphical
solution of fault problems.)
GANGUE MINERALS.
See this topic in text books cited on p. 497, also follow-
47. Catlett, Amer. Inst. Min. Engrs., XXXVIII: 358,

ing papers.
1908.
(Barite in Cuban iron ores.) 48. Lindgren, Econ. Geol., I: 163,
1906.
49. Lindgren, Amer. Jour. Sc.i, V:
(Albite in Bendigo veins.)
(Orthoclase in fissure veins.) 50. Lindgren, Econ. Geol.,
418, 1898.
V: 522, 1910. (Anhydrite.) 51. Rogers, Econ. Geol., VI: 790, 1911.
(Orthoclase
bearing veins.)
MAGMATIC DIFFERENTIATION.
52. Garrison,
Min. and
Sci. Pr.,
XCVIII:
53. Gregory, Smithson, Inst., Ann. Rept., 1908: 311.

(Igneous ore.) 54. Read, Econ. Geol., I: 111, 1906. (Phase rule and igneous magma.) 55. Spurr, Amer. Inst. Min. Engrs., XXXIII: 288,
45, 1909.
(Magmatic segregation.) 56. Spurr, Econ. Geol., II: 178, 1907.

and Steel Inst,, Jour., LXXIV: 106, 1907. (Lap58. Vogt, Zeitschr. prak. Geol., I: 4, 125 and 237, 1893.
59.
land.)
(Problems in GeolVogt, Amer. Inst. Min. Engrs., XXXI: 125, 1902.
60. Watson and Taber, Va. Geol. Surv., Bull.
ogy of Ore Deposits.)
1903.
57. Stutzer, Iron
II1-A.,
1913.
(Rutile deposits.)
See also references
METALLOGENETIC EPOCHS AND PROVINCES.
2, 13, 21, p.
61. Finlayson,
Quart.
497.
Jour.
Geol. Soc., LXVI: 281, 1910.

(Metallogeny British Isles.) 62. de
Launay, Traite de Metallogenie. Paris, 1913. 63. de Launay, Ann.
(Metallogeny Asiatic Russia.)
Mines, 10th ser., XV: 220 and 303, 1909.
de Launay, Internat. Geol. Cong., 10th session, 1906. (Metallogeny Italy.) 65. Lindgren, Econ. Geol., IV: 409, 1909 and Can. Min.
Inst. XII.
(Metallogenetic epochs, U. S.) 66. Miller and Knight, Cnt.
64.
Bur. Mines,
67. Spurr,
Geol.
XXIV,
Amer.
Surv.,
Prof.
(Pre-Camb. epochs Ontario.)

243, 1915.
Min. Engrs., Trans., XXIII: 328, 1903, and U. S.
Pt. I:
Inst.
Pap.,
42:
276,
1905.
(Metalliferous
provinces.)
METALLOGRAPHY. 68. See Refs. 3 and 14, p. 497.

METAMORPHISM. 69. Clarke, U. S. Geol. Surv., Bull., 616: 1916. 70.
71. Van
Leith and Mead, Metamorphic Geology. New York, 1915.
(Treatise on MetamorphHise, U. S. Geol. Surv., Mon., XLVII, 1904.
ism.)
ORE DEPOSITION.
72. Barus, Amer. Inst. Min. Engrs., XIII: 417, 1885.

73. Butler, Econ. Geol., X: 101,
(Electrical activity in ore bodies.)
74. Emmons,
1915.
(Rel'n ore deposits to different intrusive types.)
S. F., Min. and Sci. Pr., C: 739, 1910.
(Former theories ore deposition.)
75.
Emmons,
S. F.,
Geol. Soc. Amer., Bull.,
XV:
1,
1904.
(Ore dep'n
ORE DEPOSITS
499
76. Emmons, W. H., Econ. Geol., III: 611, 1908.

(Mineral
77. Fox, Amer. Jour.
according to depositional conditions.)
Sci., XXXVII: 199, 1839.
(Vein form'n by galvanic agencies.) 78.
Gillette, Amer. Inst. Min. Engrs., XXXIV: 710, 1903. (Osmosis theory.)
theories.)
class'n
Hatscheck and Simon, Inst. Min. and Met., Trans., XXI: 451, 1912.
(Gels in rel'n to ore dep'n.) 80. Kemp, Amer. Inst. Min. Engrs., Trans.,
XXXIII: 699, 1903. (Rel'n igneous rocks to ore dep'n.) 81. Kohler,
79.
XI: 49, 1903. (Adsorption as factor in ore form'n.)

Min. and Sci. Pr., CVII: 418, 1913. (Gels.) 83. Lindgren,
Econ. Geol., II: 105, 1907. (Phys. cond'ns ore dep'n.) 84. Posepny,
Amer. Inst. Min. Engrs., Trans., XXIII: 197, 1894. (Genesis of ore
85. Spurr, Econ. Geol., VII: 485, 1912.
deposits.)
(Theory of ore
86. Sullivan, Econ. Geol., I: 67, 1906, and U. S. Geol.
deposition.)
Surv., Bull. 312. 87. Sullivan, Econ. Geol., Ill: 750, 1908.
(Precipitation by filtration.)
88. Van Hise, Amer. Inst. Min. Engrs., Trans.,
XXX: 27, 1901. (Deposition of ores.) 89. Weed, Eng. and Min.
Jour., LXXIX: 365, 1905.
(Adsorption.) 90. Wells, Econ. Geol.,
V: 1, 1910, and U. S. Geol. Surv., Bull. 609, 1915. (Fractional precipitation of sulphides.)
91. Wells, Econ. Geol., VIII: 571, 1913 and U. S.
Zeitschr. prak. Geol.,
82. Krusch,
(Electrochemical activity.)
92. Irving, Econ. Geol., Ill: 143, 1908.
(Classification.)
For discussion see Ibid., Ill, pp. 224, 326, 425, 534, 637, 1908. 93.
Lindgren, Econ. Geol., IV: 56, 1909. 94. Penrose, Econ. Geol., V: 97,
ORE SHOOTS.
1910.
(Causes of.) 95. Pope, Econ. Geol., VI: 503, 1911.
(Magmatic differentiation as cause of.) 96. Winchell, Econ. Geol., Ill:
425, 1908.
97.
Emmons, W.
98. Storms,
Min. and
OUTCROPS.
H., Min.
Sci. Pr.,
and
Sci. Pr.,
XCIX:
751, 782, 1909.
CI: 537, 1911.
REPLACEMENT. 99. Fenner, Sch. M. Quart., XXXI: 235, 1910. (Rhyolite

by stephanite and chalcopyrite.) 100. Irving, Econ. Geol., VI: 527
and 619, 1911. (General.) 101. Krusch, Zeitschr. prak. Geol., XVIII:
165, 1910.
(Primary and secondary processes in ore bodies.) 102.
Discussion by
(General.)
Lindgren, Econ. Geol., VII: 521, 1912.
103. Lindgren, Amer. Inst. Min.
Stevens, Ibid., VIII: 397, 1913.
Engrs.,
Trans.,
Amer. Jour.
XXX:
Sci.,
Econ. Geol., VII:
SECONDARY SULPHIDE
1913.
104. Smyth,
(In fissure veins.)
578, 1901.
105. Turner,
(Quartz by pyrite.)
277, 1905.
(Siliceous rock by pyrite.)
708, 1912.
ENRICHMENT. 106. Bastin, Econ. Geol., VIII: 51,
XIX:
(Metasomatism
in
downward
sulphide
enrichment.)
107.
108. Emmons,
(Silver ores.)
Cooke, Jour. Geol., XXI, No. 1, 1913.
S. F., Amer. Inst. Min. Engrs., Trans., XXX: 177, 1901.
109. Emmons, W. H., Econ. Geol., X: 151, 1915. (Temp, chalcocite zones.)
110. Emmons, W. H., U. S. Geol. Surv., Bull. 529, 1913.
(General
111. Graton and Murdock, Amer. Inst. Min. Engrs., Trans.,
treatise.)
XLV: 26, 1914. (Copper ores.) 112. Grout, Econ. Geol., VIII: 407,
1913.
alk.
(Reaction cold acid sulphate solutions copper, silver, gold, and

met. sulphides.) 113. Kemp. Econ. Geol., I: 11, 1906.
sol'n
114. Palmer and Bastin, Econ. Geol., VIII: 140, 1913.

ores.)
Discussion by
(Metallic minerals as precipitants of silver and gold.)
(Copper
ECONOMIC GEOLOGY
500
X: 580, 1915.
Elley, Ibid.,
1915. (Silver ore experiments.)
117. Rogers,
1910.
(Criteria.)
115. Ravicz,
Econ.
X:
Geol.,
368,
Ransome, Econ. Geol., V:

Min. and Sci. Pr., CIX: 680.
116.
205,
1914.
119.
118. Sales and Gregory, Econ. Geol., V: 678, 1910.
(Criteria.)
120.
(Chalcocite enrich't.)
Spencer, Econ. Geol., VIII, No. 7, 1913.
Tolman, Min. and Sci. Pr., CVI: 38, 141 and 178, 1913. 121. Tolman,
Amer.
Min. Engrs.,
Inst.
122.
references.)
Bull.,
Weed, Amer.
(Chalcocite enrichment and

Min. Engrs., Trans., XXX: 424,
Feb. 1916.
Inst.
1901.
(Gold and silver.)
VEINS, ORIGIN, STRUCTURE, ETC.
123. Bancroft, Amer. Inst. Min. Engrs.,

(Formation and
245, 1908: and XL: 809, 1910.
124. Beck, Zeitschr. prak. Geol., XIV: 71, 1906; and
enrichment.)
Geol. Mag., Dec. v, III, No. 1, 1906.
(Relation between ore veins and
Trans.,
XXXVIII:
Emmons,
125.
pegmatites.)
S. F., Col. Sci. Soc., Proc., II:
126. Emmons,
(Origin of fissure veins.)
1909.
127. Glenn,
(Segregated veins.)
W.
189, 1885.
H., Econ. Geol., IV:
Amer.
Inst.
Min.
755,
Engrs.,
XXV:
128. Kemp, Econ. Geol., VIII:

(Fissure walls.)
499, 1896.
129. Kemp, Econ. Geol. I: 207,
(Artificial vein form'n.)
543, 1913.
1906.
(Problem of metalliferous veins.) 130. Kemp, Amer. Inst.
Min. Engrs., XXXI: 169, 1901. (Igneous rock and vein formation.)
131.
ard,
Kemp,
Amer.
M. Quart., XIII: 20, 1892. (Filling.) 132. RickMin. Engrs., Trans., XXXI: 198, 1902. (Bonanzas in
Sch. of
Inst.
(Vein walls.)
Ibid., XXVI:
193, 1897.
XL: 475, 1909. (Law of fissures.) 135. Weed,
Eng. and Min. Jour., LXXXIII: 1145, 1907.
(Displacement by inter133. Rickard,
gold veins.)
134. Stevens, Ibid.,
136. Weed, Ibid., LXXIV: 545, 1903.

(Enrich't by
secting fissures.)
137. Weed, Amer. Inst. Min. Engrs.,
ascending alkaline waters.)
XXXIII: 747,1903.
Ibid.,
XXXI:
(Enrich't
634, 1902.
by ascending hot
waters.)
138.
Weed,
(Effect of wall rock.)
WATERS, MINE, SPRING AND UNDERGROUND.

(Mineral
prak. Geol., XVI: 401, 1908.
139. Delkeskamp, Zeitschr.
140. Emmons
Springs.)
(Comparison of mine
653, 1913.
Harrington, Econ. Geol., VIII:

141. Emmons and Larsen,
hot spring waters.)
235,
1913.
(Wagon Wheel Gap,
Colo.)
and
and
Econ. Geol., VIII:

Ann. Min.
142. Gautier,
Translated Econ. Geol., I: 688, 1906.

(Ther6ser., IX: 316, 1906.
mal waters and relation to vulcanism.) 143. Fine 11 Proc. Colo. Sci. Soc.,
144. Hague,
VII: 193, 1904.
(Underground water and ore
p'n.)
x
(Yellowstone Park waters.)

Min. Engrs., Bull., Feb. 1908. (Volcanic
Hodge, Econ. Geol., X: 123, 1915. (Mine waters in
147. Kemp, Amer. Inst. Min. Engrs., Trans. (Ground
sulphides.)
148. Lane, Eng. and Min. Jour., XII: 1909.
(Mine waters.)
waters.)
149. Lindgren, Amer. Inst. Min. Engrs., Trans., XXXVI: 27, 1905.
(Steamboat Springs, Nev.) 150. Lindgren, Econ. Geol., V: 22, 1910.
151. Mendenhall, Ibid., IV: 35,1909.
(Ground water.)
(Ojo Caliente.)
152. Tolman, Min. and Sci. Pr., Mar. 16, 1912.
(Magmatic origin of
Geol. Soc. Amer., Bull.,

145. Hastings,
146.
waters.)
Amer.
ore solutions.)
153.
spring deposits.)
227, 1900.
XXII:
103, 1911.
Inst.
Weed, U. S. Geol. Surv., Bull. 260, 1905. (Hot

Weed, U. S. Geol. Surv., 21st Ann. Rept., II:
154.
ORE DEPOSITS
501
and Gottschalk, Econ. Geol., V: 28, 1910.

156.
ox'n of sulphides.) Also Ibid., VII: 15, 1912.
(Weathering ore deposits.) 157.
Penrose, Jour. Geol., II: 288, 1894.
Steidtman, Econ. Geol., Ill: 381, 1908. (Graphic comparison of alter-
WEATHERING.
155. Buehler
(Experimental
ation
by weathering and hot
158. Winchell, Econ. Geol.,

best general discussions are in
solutions.)
(Ox'n of pyrite.)
290, 1907.
textbooks. See also Ref. 110, 120.
II:
The
159. Apgar, Amer. Inst. Min. Engrs., Trans.,

(Use of microscope in mining engineering.) 160.
Becker and Day, Wash. Acad. Sci., Proc., VII: 283, 1905. (Linear
161. Emmons, S. F., Amer. Inst. Min.
force of growing crystals.)
MISCELLANEOUS TOPICS.
XLVII:
65, 1914.
XXII: 53, 1894. (Geol.

Emmons, S. F., Ibid., XVI: 804, 1888.
163. Emmons, S. F., Min. and Sci. Pr.,
Engrs., Trans.,
distrib'n useful metals.)
162.
(Struct rel'ns of ore deposits.)

(Forms of ore
Sep. 22, 1906.
XXXIX:
164. Hastings, Amer. Inst. Min. Engrs., Trans.,

deposits.)
165. Irving, Smith and Ferguson,
(Origin pegmatites.)
104, 1909.
Ore Deposits, pub'd by Amer. Inst. Min. Engrs., 1913. (Many mis166. Kemp, Can. Min. Inst., XII: 356, 1910;
Min. and Sci. Pr., Mar. 20, 1909. (What is an ore.) 167. Lindgren,
Econ. Geol., I: 34, 1906. (Ore dep'n. and deep mining.) 168. Rick(Persistence of ore
ard, Inst. Min. and Met., Bull. 122, Nov. 12, 1914.
169. Rogers, Econ. Geol., VII: 638, 1912.
in depth.)
(Paragenesis.)
170. Stevens, Amer. Inst. Min. Engrs., Trans., XLVII: 91, 1914.
(Laws of jointing.) 171. Vogt, Zeitschr. prak. Geol., VI: 225, 314, 377
and 413, 1898; VII: 10, 1899. (Distribution of elements and conc'n
172. Wagoner, Amer. Inst. Min. Engrs.,
of metals in ore bodies.)
(Gold and silver in sedimentary rocks.)
Trans., XXXI: 798, 1902.
173. Washington, Amer. Inst. Min. Engrs., Trans., XXXIX: 735, 1909.
174. Wells, Econ. Geol., VI:
(Distrib'n of elements in igneous rocks.)
cellaneous references.)
175. Wright and

1911.
(Hydrolysis in geological chemistry.)
(Quartz as
Larsen, Amer. Jour. Sci., 4th ser., XXVII: 421, 1909.
211,
geologic thermometer.)
CHAPTER XV
IRON ORES
IRON is an abundant constituent of the earth's crust, and yet few
minerals are capable of serving as ores of this metal, because they
do not contain it in the right combination or in sufficient quantity
to
make its extraction possible or profitable.

The iron ores having the greatest commercial value
at the present
day are usually those which are favorably located, of high quality,
in considerable quantity, and possessing a structure such as to render
These four requirements have been met to
their extraction easy.
such an eminent degree by the deposits located in the Lake Superior
district that they now form the main source of supply for furnaces
in the eastern and central states, and many of the iron mines in
the eastern part of the United States have found it difficult to compete with them, although it is true that a number of deposits are
worked to supply local demand, owing to their proximity to furnace,
flux, and coal, or because they possess certain desirable characteristics.
The
Iron-ore Minerals.
their composition
ore minerals of iron, together with

of metallic iron, are:
and theoretic percentage

Fe O 4
.....
MAGNETITE.
HEMATITE.
Magnetic iron
LiMONiTE. 1
Brown
SIDERITE.
Spathic ore, blackband, clay-iron stone, kidney
ore,
Specular iron ore, red hematite,
Fe 2 O
ore,
fossil ore,
70%
hematite, bog iron ore, ochre,
brown ore
2Fe 2 O 3 3H,O
59.89%
ore,
FeCO 3
Of subordinate value:
PYRITE.
FeS 2
FRANKLINITE. (Fe, Zn,
PYRRHOTITE.
72.4%
Clinton
48.27%
....
.
Mn)O,
(Fe,
Mn) O
2
Chiefly FeS
46.6%
44.1%
61.6%
Magnetite is black, often granular with a metallic luster. It has a black

streak, hardness of 5.5-6.5, specific gravity of 5.5-6.5, and is strongly magnetic.
1
The group name
"
brown
ore
oxides, such as limonite, turgite,
"
is sometimes used
and gothite.
502
to include several
hydrous
IRON ORES
Some
503
may run high in titanium, especially those found in basic

Hematite is red to brownish red, steel-gray, or even black.
It is commonly fine-grained, but the specular varieties may be quite coarse.
It ranges from massive to powdery, and has a specific gravity of 5.2. Limonite
is never crystalline, and varies widely in appearance; some forms are powdery,
others massive, and these may be porous, vesicular, stalactitic, or even,
occurrences
igneous rocks.
though rarely, solid. The specific gravity is 3.8. The color is brown to
brownish yellow on the fracture, but may be black and shiny on the natural
surface. Gothite (Fe 2 O 3 H 2 O) and other hydrous oxides with less water than
limonite are sometimes associated with it.
Indeed much of the commercial
limonite or brown ore is an intimate mixture of several of the hydrous oxides of
iron.
Siderite, when occurring in commercial quantities, is rarely in cleavable
form, but occurs as a fine-grained mass, with impurities. Hematite is by
far the most valuable of the iron-ore minerals, chiefly on account of its easier
reduction, but also because of the greater richness of the known important
,
deposits.
The
deficiency in iron content shown by many ores is due to the

presence of common rock-forming minerals in the gangue, the impurities which they supply being alumina, lime, magnesia, silica,
and also metallic minerals which have titanium, arsenic, copper,
phosphorus, and sulphur.

to weaken the iron.
The
effect of the last four is in general
because it displaces iron, and because just so much

required to flux it, but some furnaces turn out iron for foundry purposes containing 10 or more per cent. Ores carrying as high as 40 per cent
SiO 2 are used in small quantities. Lime in small amounts does no harm.,
Silica is objectionable
lime
is
but in large quantities needs to be fluxed off. It is not present in any quanAlumina may
tity in limonite, but may run high in the Clinton red ores.
run somewhat high in limonites, because of admixed clay. Pyrite is the
common source of the sulphur, but in some limonites it may come from
gypsum or barite. Titanium, a common ingredient, is found in some quantity
in
many magnetite deposits
(see Titaniferous magnetites, also refs. 28, 30, 33a)
and up to the present time has rendered them practically useless, not because
it interferes with the quality of the iron, but because it makes the ore highly
Experiments have been
refractory, and drives much of the iron into the slag.
made
looking towards the utilization of these titaniferous magnetites for the

manufacture of ferrotitanium; indeed these have been used for several years
in the manufacture of this alloy, for although rutile is preferred it is too
Manganese, when present, is found mostly in the limonite ores
expensive.
and for certain purposes is desirable. It is also prominent

Lake Superior ores. Apatite yields the phosphorus. As
in
some
this
of the
cannot le
eliminated in either the blast furnace or the acid converter used in making
Bessemer steel, and as the allowable limit of phosphorus in pig iron used for
purpose is Y& P er cent, a distinction is usually made between Bessemer

and non-Bessemer ores, the maximum amount of phosphorus permissible in
iron ore to be used for this purpose being rcr&o of the percentage of metallic
this
ECONOMIC GEOLOGY
504
iron contents of the ore.
falls
The phosphorus contents
of
many
high-grade ores
considerably below the allowable limit.
Classification.
Iron-ore deposits have originated in a
of different ways, including:
New
(Lake Sanford,
York,
1.
number
Magmatic
etc.)
2.
segregation deposits
Contact-metamorphic de-
Utah; etc.).
Sedimentary ores (bedded
hematite and limonite, bog ores, etc.). 4. Ores concentrated by
meteoric waters, and deposited as replacements (some Lake
3.
posits (Iron Springs,
Superior hematites, Qriskany limonites), or in residual materials

5. Lenticular masses in
(Virginia Cambro-Silurian limonites).
(some magnetite and pyrite

Gossan ores (limonite capping of many sulphide
7. Replacements by ascending waters;
and 8.
rocks, of variable origin
metamorphic
6.
deposits).
ore bodies).
Placer deposits (magnetite sands).
Iron-ore bodies may show a variety of form, but many of the
important deposits known in this country are lens- or basin-shaped
in outline.
Irregular masses and beds are not uncommon.
Iron ores show a wide geologic distribution, those found in the

United States for example ranging from pre-Cambrian to Recent.
The occurrences
of the different kinds of ore are best discussed
separately, and for practical as well as for other purposes a

mineralogic and geographic grouping seems better in this case
than a genetic one.
MAGNETITE
United States.
Magnetite occurs (Fig. 153) (1) as lenticular
masses commonly in metamorphic rocks; (2) as more or less lensshaped and tabular bodies in igneous rocks; (3) as sands on the
and seas; (4) as contact-metamorphic deposits;

as replacements in limestone, not of contact-metamorphic
character; (6) as veins, and (7) in residual clays.
shores of lakes
(5)
The first class includes the most important deposits now worked
The second and third groups run too high in
titanium to have any commercial value at the present time, but
l
in this country.
the second
may become
over some of
of importance in the future,
and more-
representatives are of large size.

Examples of
the fourth class are known at a number of points in the West,
and while few of them are worked, they may some day become
its
of great importance.
netite.
The
1
This
is riot
carry hematite in addition to magand seventh groups are unimportant.
They
fifth, sixth,
true of
all
the European deposits, see p. 517.
IRON ORES
505
Distribution of Magnetites in the United States 1 (Fig. 153).

Non-Titaniferous Magnetites.
These are usually found in the
form of lenticular deposits in metamorphic rocks.

important
The most
series of occurrences lies in the crystalline belt of rocks
New York into Alabama, deposits being known in

New York, New Jersey, Pennsylvania, Virginia, and North Caroextending from
lina.
107
FIG. 153.
The
Longitude
West
93
from
Gretowich
91
Map showing distribution of hematite and magnetite deposits in the

United States. (After Harder, U. S. Geol, Sum., Min. Res., 1907.)
which are interbedded with gneisses of either acid or

and often conform with the latter in dip and strike,
are of variable size, and may occur either singly or in series, the ore
body commonly showing pinching and swelling, or even faulting.
Well-defined boundaries are sometimes wanting.
Feldspar, hornblende, and quartz are common gangue minerals, while apatite is
lenses,
basic character
Although the ore as mined is frequently of

be shipped direct to the blast furnace, in some
instances it is so lean as to require concentration by magnetic
methods. A description of one or two occurrences will serve as types
Adirondack Region, New York (27, 30)
The rocks of the Adirondack region (Fig. 154) are almost exclusively of pre-Cambrian age,
prominent in some.
sufficient purity to
with occasional
1
Magnetites
inliers of
the bordering Paleozoic strata, whose basal
in general fall into
two
the non-titaniferous and titaniferous.
classes
on basis
of titanium content, viz.
ECONOMIC GEOLOGY
506
FIG. 154.
Geologic
map
of
Adirondack Region, New York, showing location of

(After Newland, Econ. Geol., II.)
iron-ore deposits.
member, the Potsdam sandstone, rests unconformably on the older

crystallines. The latter have in most cases been subjected to powerful compression, and sometimes greatly changed by metamorphism,
much
in fact so
so that their original character
is
determinable with
difficulty.
The
I.
following
members
Metamorphic
are recognized, beginning with the oldest:
rocks.
These
Sedimentary or Grenville Series.
and dolomites, often impregnated wijth pyrite,

graphite, and silicates, and by an increase in the latter may pass
into schists. Both rock types occur in long narrow belts, bounded
consist of limestones
by sedimentary
showing
2.
gneisses.
Gneisses of acid
to basic character,
garnet, sillimanite, graphite, cyanite, pyrite, etc.
phibolites,
composed mainly
of hornblende
and
feldspar,
may be metamorphosed dikes or magnesian shale.

infrequent occurrence.
5.
3.
often
Am-
and which
4. Quartzites of
Gneisses of doubtful relationships.
IRON ORES
II. Igneous Rocks.
These include: (1) anorthosite (the earliest),
gabbro, syenite, and granite, all connected by intermediate rock
types and probably representing derivations from the same magma.
Dikes, mostly diabases.

The non-titaniferous magnetites are the most widespread
of the Adirondack ores, and occur on both the eastern and western
(2)
Ores.
sides of the mountains.
MAP OF THE
LAKE C.HAM PLAIN & MQRIAH
RAILROAD
Scale.1 incl
FIG. 155.
Map
N. Y., iron-ore district.

Min. Jour., LXXXI.)
of Mineville,
(After Graribery, Eng.
and
The ores vary from impure lean varieties, consisting of magnetite

mixed with the country-rock minerals (i. e. quartz, feldspar, pyrox-
The richest ore averene, hornblende, etc.), to pure magnetite.

ages 60 to 70 per cent iron, and comes chiefly from Mineville, while
those ores carrying under 50 per cent have to be concentrated.
The phosphorus content
is variable, but seems to be lower in the

leaner ones, while in the non-Bessemer ores it may exceed 2 per
cent.
The amount of sulphur is also changeable, but is highest
in those ore bodies
found in the Grenville
gneiss.
ECONOMIC GEOLOGY
508
While the ore bodies are variable in shape they show in general a
somewhat lenticular cross-section, with the tabulation extending
parallel \vith the strike; but regularity is more common on the
north and west sides of the province, for in the eastern districts
the greatest irregularity due to a complexity of pinches,
and compressed folds. The wall rocks include gneisses
of granitic, syenitic, and dioritic composition, as well as schists
and occasionally limestones.
The ore bodies at this locality are
Minerille, New York (30).
the largest and most productive in New York State at the present
there
is
swells,
time.
They
FIG.
are of lenticular character, but in
156.
Thin section
netite (black);
some
cases the lenses
gneiss, Lyon Mountain, N. Y.

pyroxene (crossed cleavage). X30.
of magnetite
feldspar (gray);
Mag-
and of such extent as to be commonly spoken of as beds;

moreover, some of them have been bent over into a southwesterly
pitching fold, whose crest has been stretched and pinched, while
faulting at the northern end of this has complicated the structure.
The ores occur as integral members of the syenite series, and are
are so
in the
flat
form of layers conformable to the banding or foliation of
the inclosing rocks.
There are at least three large ore bodies (Fig. 157), viz.
1. The Barton Hill ore body, forming a practically continuous
bed, whose outcrop is approximately 3500 feet long in a direction
:
PLATE XLIII
FIG.
1.
left to
of open cut in magnetite deposit, Mineville, N. Y.

The pillars are
support the gneiss hanging wall. (After Witherbee, Iron Age, Dec. 17,
View
1903.)
FIG.
2.
General view of magnetic separating plants and shaft houses, Mineville,

N. Y. (After Witherbee, Iron Age, 1903.)
(509)
ECONOMIC GEOLOGY
510
a
little
trates,
Iron content, 30-35

Fe, .025 per cent P.
east of north.
65 per cent;
per cent;
concen-
Longitudinal Scctiou><l"Mine to-B"Shaft
GEOLOGICAL CROSS-SECTION
TO ACCOMPANY
MAP OF THE MINEVILLE AREA

EXPLANATION
1Z3
ESS
Drift
Gneiss
Datum
FIG. 157.
\s
can
Gabbro
Trap Dike
Ore Veins
is level
of
Lake Champlain
Sections of the old,

(After Granbery,
2.
Hill,
The Harmony
and
bed,
"21 "-Bonanza-Joker ore beds, Mineville, N. Y.

Eng. and Min. Jour., LXXXI.)
ying to the southwest ward of Barton
striking northwest, with a rather flat southwest dip.
IRON ORES
10 to 20 feet thick and cut
It is
by
511
several
narrow trap dikes
which occupy fault planes of 10 to 50 feet displacement.

3.
large ore body which appears to be made up of three principal
and separated parts, known as the Miller, the Old Bed or Mine 23,
"
and the 21"-Bonanza-Joker. This is the chief source of the ore.
some doubt whether there is any connection between the

This Old Bed group extends in a praca half mile, exhibiting at the same
stretch
for
about
unbroken
tically
time a most complex fold, referred to above.
The ores are granular masses of magnetite which in the Barton
Hill group were prevailingly of Bessemer grade, but which in the Old
There
is
Joker and the Harmony.
Bed series are high in phosphorus.

The lean ores are mixed with the minerals of
among these the basic syenite is the chief one.
the wall rocks, and
At Lyon Mountain (30) the ore is a lean magnetite traceable for 6 miles
and from 20 to 200 feet wide, and occurs in a rock intermediate between
granite and syenite. Most of the ore is low in phosphorus, the concenabout .008 per cent P and 65 per cent Fe.
In northern New Jersey, the magnetite deposits form
layers or bands in the Franklin (pre-Cambrian) limestone, or as flat lenses
trates carrying
New
Jersey.
in the associated gneisses.

The ore according to Bayley (24a) consists mainly of magnetite, horn-
pyroxene, and apatite, sometimes intimately mixed. Pyrite and

quartz are not uncommon, and all the associated minerals occur in the
country gneiss.
The ore bodies, which are lens-shaped, lie with their longer axes conforming to the foliation of the gneisses, and the ore usually grades into the
Several
gneiss, although sharp boundaries are in some cases known.
lenses may overlie each other, and then the intervening rock may be either
gneiss, pegmatite full of magnetite, or coarse-grained hornblendic rock,
with ore veinlets paralleling the foliation of the gneiss. This series of
magnetites extends northeastward into the Highland region of New York.
blende,
Origin of Magnetites. The origin of the magnetites found in the

gneisses has formed a puzzling problem to geologists, whose
correct solution depends in part at least on the correct interpretation
of the origin of the inclosing rocks.
If
the gneisses are of sedimentary origin, then
it is
possible that the
represent metamorphosed deposits of magnetite sands,

limonite, or siderite, and the parallelism of the ore bodies with the
foliation of the gneisses might be regarded by some as evidence in
ores
may
favor of such a view.
ECONOMIC GEOLOGY
512
But even if the gneisses were of sedimentary origin, it might still

be possible that the ores were of later introduction, as has been
suggested by some. Thus Keith held the view that the North Carolina magnetites were replacement deposits (26), while
Kemp formerly advanced the theory that the ore bodies at Mineville (27) have
been formed by iron-bearing magmatic waters, which were given
off from the neighboring gabbros and penetrated the gneisses while
the latter were probably still at great depths, and before their
metamorphism was complete. The presence of apatite and fluorite

was thought to show that mineralizing vapors also played a part.
A similar origin was suggested by Spencer for the New Jersey magnetites (34).
Later studies by Kemp and Newland in the Adirondacks (30)

seem, however, to indicate that the acid gneisses are probably of
igneous origin, and that the magnetites themselves are products
magmatic differentiation. That there is no obstacle to this

theory is shown by Newland, who points out that the acid igneous
rocks of the region contain a large excess of iron over the amounts
combined with the lime and magnesia to form silicates. The peculiar form of some of the ore bodies is likewise perhaps only
of
explainable by this theory. A fact not to be overlooked, however,

is the occurrence of fluorite, apatite, hornblende, etc., intercrystallized with magnetite, or the frequent association of the latter with
pegmatite or vein quartz, a group of conditions which are suggestive of mineralizing agents, and their deposition by pneumatolytic
or aqueous action.
A somewhat unique deposit occurs at

Cornwall, Pennsylvania (35).
Cornwall, Lebanon County, Pennsylvania, and at several other localities
The ore is found along the contact of Triassic
in southern Pennsylvania.
diabase, with Cambro-Ordovician limestones or more rarely Triassic shales,
and consists mainly of magnetite, but carries sufficient pyrite to require
The ore forms large
roasting, and occasionally a little specular hematite.
and small masses of irregular shape, lying either within the sediments or
along the contact, and while it appears to be a true contact metamorphic
The ore averages about
deposit, the contact silicates are not prominent.
45 per cent iron, is low in phosphorus, but high in sulphur, silica, lime, and
magnesia. It also carries some copper.
Iron deposits are widely scattered
Iron Springs, Utah (29).
over the western states, but few have been worked, owing to the
limited demand in that region.
They can be regarded, however,
as reserves which
Among
the best
may become
known
of
importance in the future.
of these are those of the Iron Springs
IRON ORES
of
district
513
southwestern Utah, which belongs to the contact-
metamorphic type.
At
this locality the series of sedimentary rocks ranges
boniferous to Pleistocene (Fig. 158), and
from Car-
intruded by three laccoliths of biotite andesite, which have especially affected the Homeis
Pleistocene and Recent

lake,
stream and outwash
f (3
deposits
e
PleistoceneC?) conglomerate
(100'JQi
rt
Late tuffaceousrhyolite
(400')
Biotite- hornblende- pyroxen
andesite (200')
Biotite dacite
(300')
Pyroxene andesite brec^

cia and agglomerate *:
(1000
Hornblende andesite "I
breccia and agglomer->ate (150')
Latest trachyte
50'-
300
),-
Later trachyte (50')''

Early tuffaceous rhyolit*
(300'- 400')
Early trachyte
50'- 600'
Claron limestone, conglomerate

and sandstone (1000 ?)
1
Pinto sandstone, shale, conglomand limestone lenses

(1,500';
erate
Homestake limestone (50'- 500')
Biotite andesite
FIG. 158.
Geologic column of the Iron Springs, Utah district.

and Harder, U. S. Geol. Sun., Butt. 338.)
(After
Leith
ECONOMIC GEOLOGY
514
stake (Carboniferous) limestone, and to a lesser extent the Claron

(Tertiary) limestone.
The ore bodies are of three types,
viz.:
(1)
fissure veins
in
andesite; (2) fissure and replacement deposits on the contact of

the andesite and Carboniferous limestone; and (3) as breccia cement
in Cretaceous quartzite.
Map of a portion of the Iron Springs, Utah district, showing occurrence

of iron ore in limestone near andesite contact, and also in the igneous rock.
FIG. 159.
(After Leith
and Harder, U.
S. Geol. Surv., Bull. 338.)
The second of these is the most important, and while the ore
bodies are roughly lens-shaped, with their longer diameters parallel
to the contact, still there are numerous irregularities, due to faulting
and other
causes.
deepest test shaft is
The vertical dimensions are unknown, as the

down only 130 feet, and has not reached water
level.
The
ore consists of magnetite and hematite with a small amount

first two, of course, being characteristic of contact-
of limonite, the
The
ore shows a hard, crystalline texture

sometimes found in arid regions, becomes
softer with depth.
The gangue is chiefly quartz or chalcedony near
the surface, but calcite increases with depth. The contact minerals,
metamorphic
deposits.
at the surface, but, as
is
IRON ORES
garnet, diopside, apatite, mica, hornblende,
515
and other
silicates,
are
minor constituents.
500 feet
district,
ore
a, iron
Homestake limestone
b, laccolithic
;
e,
Mound
contact deposit, Iron Springs, Utah

d, altered
c, Homestake limestone
Pinto sandstone. (After Leith and Harder, U. S. Geol.
Cross section of Desert
FIG. 160.
andesite
Sun., Bull. 338.)
While much of the ore runs above 60 per cent in iron, the average
about 56. Phosphorus is uniformly high, but sulphur, copper, and
titanium are not in prohibitive amounts.
is
Leith and Harder believe that the ores are closely related in origin
to the andesite laccolith intrusions, and suggest the following
The contact metamorphism first produced a zone of about 60
:
feet width, containing
varying amounts of
albite, kaolinite, actin-
diopside, quartz, orthoclase, serpentine, phlogopite, andradite, iron ores, osteolite (earthy apatite), andalusite, wollastonite,
There is also glassy material which appears to reprecalcite, etc.
olite,
Solutions given off by the andesite dissolved out the lime and magnesia carbonates, while the residue
Later the iron was brought in from
recrystallized to form silicates.
sent fused wall rock.
the eruptive, probably as ferrous chloride, which reacted with water

(above 500 C.), yielding magnetite and hydrochloric acid, thus:
The.
HO=
Fe3 O 4 + 6 HC1 + H + 77 calories.

HC1 attacked the limestone, which was replaced by the mag-
3 FeCl 2
netite.
This view that the eruptive contributed but little material to the
is disputed by Kemp, who, by taking the author's
analyses and recasting them, shows that the reverse may be true.
contact zone
Moreover, if Leith's conclusions are correct, then a contact zone

60 feet thick must represent a shrunken residue of a limestone belt
300 feet thick which, as pointed out by Kemp, seems hardly
possible.
Small deposits of magnetite are found in the

Group and their residual clays in southwestern
The magnetite, which is associated with hematite and
Other Occurrences (16).
limestones of the Shenandoah

Virginia (16, 23a).
516
ECONOMIC GEOLOGY
high grade and low in phosphorus (23a).

Magnetite occurs
sparingly in the Marquette Range of Michigan, where it is found in the schists.
Contact-metam orphic deposits are found at a number of localities in the
siderite, is of
West, but the chief occurrences are in Colorado, New Mexico, Utah, and
That at Fierro, N. Mex. (25a) occurs in Paleozoic limestone,
near its contact with a Tertiary monzonite porphyry. Another found at
California.
Heroult, Calif.,
lies chiefly
at the contact of diorite
and
Triassic limestone
(32).
Analyses of Magnetites.
The
following table gives the com-
position of non-titaniferous magnetites from a number of localities.

It is not possible in all cases to obtain analyses of recent date.
ANALYSES OF MAGNETITES
IRON ORES
The
517
believed to be a replacement of the schistose quartz

porphyry along sharply denned zones, and the banded structure
may be an original one.
ore
is
Moose Mountain, Out. (97)

This deposit, which is situated
north of the Sudbury nickel basin (page 796) is one of the largest
The magnetite shows a more or less strongly banded
in Canada.
.
due to alternations of iron ore and silica, while epidote

sometimes fills fissures in the ore, which are often bordered by
The iron
hornblende that passes outwards into magnetite.
formation which lies in Keewatin schists is steeply tilted. Ordinary banded ore runs about 36 per cent iron and is concentrated
to 55 per cent, but much of the good ore exceeds the first figure.
Texada Island, B. C. (89).
Contact-metamorphic deposits
of magnetite with some copper, occurring in limestone near
granite and diorite contacts are found on Texada Island, northwest of Vancouver, but they have not been steadily worked.
structure,
FIG. 161.
Photomicrograph
of thin section of ore
from Kiruna, Sweden.
Black
magnetite; white, apatite.

Two of the most remarkable deposits of,
magnetite known in the World are those of Kiruna and Gellivare in northern
Sweden. 1 That at Kiruna occurs as a great steeply dipping tabular or
dike-like mass, traceable for about 8 kilometers in the hills of Kirunavaara
and Luossavaara (Plate XLIV, Fig. 1 and Fig. 161), and has a width of
,
Amer.
Zeitschr. prak. Geol.,
Inst.
Min. Engrs., Trans.
XIV: 65 and
137, 1906.
XXXVIII: 766,1907.
Stutzer,
ECONOMIC GEOLOGY
518
The total tonnage as determined from outcrops and borestimated at 480,000,000 tons. The footwall is an orthoclase porphyry
or syenite, while the hanging wall is quartz porphyry, which in turn is overlain
32 to 152 meters.
;
is
ngs
by quartzites, clay slates and conglomerates, supposedly of pre-Cambrian age.

The ore is a fine-grained mixture consisting chiefly of magnetite and apatite (Fig. 161).
Much discussion has been aroused over the origin of these ores. Hogbom
in 1898 thought them to be due to magmatic segregation, while de
Launay
argued for a sedimentary origin, assuming that the footwall was a submarine
from which iron chlorides and sulphides emanated in gaseous form
to ferric oxide, which later was changed to magnetite
by a covering flow of quartz porphyry. Stutzer, with probably more reason,
flow,
and were then oxidized

Luossavaara
ocS-
11 I*!
?|| ||f
.3
x*
o"
Ss'ffS'S
E
|3f
i I
ogth and height 1:8,000
200
300
400
i'r3J.v,viv.jcs
|T5~ S~1~i~f3--g
?_
I
J
500 M.
Section across Luossavaara near Kiruna, Sweden.
FIG. 162.
5"
(After
Lundbohm.)
has regarded the ore as a dike, whose intrusion was preceded by the footwall
and followed by the hanging wall quartz porphyry.
At Gellivare (Plate XLIV, Fig. 2), the ore is similar to Kiruna mineralogicIt occurs as steeply dipping irregular lenses, in a
ally, but coarser grained.
gray or red gneiss, often surrounded by a curious hornblendic zone (skarn).
syenite,
The
ore
altered
is
probably similar in origin to that at Kiruna, but has been strongly
by metamorphism. 1
Other large magnetite deposits are known
in the
Ural Mountains at
Wys-
sokaia Gora and Goroblagodat. 2 Of historic and scientific interest are the
contact metamorphic deposits of magnetite with some sulphides found in the
3
province of Banat, Hungary, and first described by von Cotta.
Most interesting are the Cuban 4 deposits lying in a belt stretching eastward
from Santiago, and supplying ore which is chiefly magnetite, but carries some
hematite and pyrite, especially in its upper parts. Prominent among the
sedimentary and igneous rocks of the district is a large area of intrusive
1
Sjogren, loc.
1910.
2
3
4
cit.,
and Lundbohm, Internal. Geol. Cong., Sweden, Guidebook,
Beck, Erzlagersttaten, 3rd

Beck, loc. cit.
Kemp, Amer.
106: 2171, 1915.
ed., I:
29.
Min. Engrs., Bull. 105: 1801, 1915; Lindgren,

These contain additional references-
Inst.
Ibid., Bull.
PLATE
FIG.
1.
View
of iron ore
iron ore.
Lower
mines in Kirunavaara, Sweden. Open cuts near top

slopes chiefly hanging wall.
'
"V*
XLIV
'
*'--!
in
(H
in
Ries, photo.)
liBM-
Bttfif
Iron deposit at Gellivare, Sweden. Note pit in floor connecting with

lower workings. Walls of cut are country gneiss and in part " skarn." (H.
FIG. 2.
Ries, photo.)
(519)
ECONOMIC GEOLOGY
520
diorite,
which encloses fragments of an
deposits consist of:
(1)
The ore
older, bedded limestone.
small streaks to larger ones in limestone, with quartz,
garnet and epidote, gangue, and evidently of contact-metamorphic origin;

(2) Great tabular masses in diorite, but showing the same gangue minerals
first.
Kemp regards the latter as replacements along fracture zones in
the diorite, while Lindgren is inclined to the view that the ore bodies are a
product of contact metamorphism exerted by the diorite on included masses
as the
of limestone.
These form a
(24, 28, 30, 33a).
by themselves, and with one or two exceptions are
Titaniferous Magnetites
peculiar class
found always associated with rocks of the gabbro family. The

ore bodies usually represent products of magmatic segregation,
and may occur: (1) within the eruptive mass but grading off into
it; (2) as irregular bands (schlieren); or (3) as dikes which have
separated from the magma at greater depth, and then forced
way upward.
An exception to any of the above is the deposit at
their
Colo.,
Cebolla Creek,
part of the contact metamorphic type (336).
titaniferous magnetites are granular aggregates of mag-
which
Many
is in
and ilmenite, the relation between the two minerals being

The ilmenite is highly
usually those of a granular igneous rock.
lustrous with a rougher surface, while the magnetite shows duller,
The grains of the latter sometimes have
black, cleavage surfaces.
netite
minute intergrowths of ilmenite, which show most commonly as

lines and dots, the former representing sections of very small
ilmenite lamellae oriented parallel to the octahedral faces of the
magnetite.
The gangue minerals may be pyroxene, brown hornblende,

hypersthene, enstatite, olivine, spinel, garnet, and plagioclase.
The ores are usually low in phosphorus and sulphur, but V, Cr,
Ni, and Co are almost always present.
Titaniferous magnetites are found in many parts of the world,
the deposits being often of large size, but their possibilities have
been greatly overestimated.
This
is
due to the
fact that it is
often impossible to separate the ilmenite (non-magnetic) from the

magnetite (magnetic) to a sufficient degree, owing to the fine
intergrowths of the two.

United States (28, 33a).
In this country titaniferous magYork, New Jersey, Wyoming, MinneThe two

sota, Virginia, Colorado, etc., but are not worked.
localities of greatest importance are Sanford Hill, in the Adiron-
netites are found in
dack region of
New
New
York, and Iron Mountain, Wyo.
IRON ORES
The
following analyses illustrate their composition
521
:
ANALYSES OP TITANIFEROUS MAGNETITES
ECONOMIC GEOLOGY
522
large ones occur in the anorthosite
and
may
be segregations during
cooling, or actual intrusions forced into the anorthosite after partial

consolidation.
The
and ilmenite, the richest showand running about 60 per cent Fe. The magnetite
grains are recognizable by parting planes parallel to the octahedron
and smooth breaks, while the ilmenite grains show a rough fracture,
brighter luster, and but slight magnetism.
ing
ores are essentially magnetite
little else
Other minerals present are plagioclase, pyroxene, hornblende,
The
biotite, olivine, garnet, pyrite, apatite, spinel, and quartz.
usual order of crystallization is reversed, being silicates, pyrite,
ilmenite, magnetite.
Analyses of the Sanford deposits show
70.73-87.60 Fe 3
.007-.022
4,
.87-2.46 Si0 2
.027-028
9.45-20.03
Ti0 2
.53-4.00 A1 2
3 ;
S.
The following results were obtained by magnetic separation after crushFiner crushing would probably improve the product.
ing to 40 mesh.
IRON ORES
523
The granite is probably the youngest of the pre-Cambrian rocks, and

grades into, as well as being cut by, a biotite-pegmatite which carries some
magnetite.
Fig. 164 shows a thin section of a
low grade titaniferous ore found in
gabbro at Cumberland, Rhode Island.

These
Sands.
are
Magnetite
found in those regions where the
of
are
beach
sands
composed
weathering products of metamorphic
The sorting
and igneous rocks.
action of the waves serves to carry
the heavy mineral grains high up on
the beaches, where they form black
stieaks, composed mostly of magnetite
with
(usually
titaniferous),
monazite,
apatite,
and
mixed
other
heavy minerals.
are
known in this
Deposits
country on the shores of Lake
Champlain, Long Island, etc., but
they are of small extent as well as
lacking in quality.
New
Zealand and Brazil are said

to possess magnetite sands of commercial value.
R71W
R72W
3
iMilM
6 I 2
3i5
Kllometar
abode
Map of Iron Mountain,
Wyo., titaniferous magnetite dea, post-Devonian
posit,
6, anor-
FIG. 163.'
of
Upper Cretaceous
and carrying
titaniferous magnetMontana, but are of
Sandstones
age,
ite are
known
in
no commercial value
FIG. 164.
granite; d, gneiss; e, ore.

(After Kemp, Zeitschr. prak. Geol.,
thosite;
c,
1905.)
(36a).
Section of Cumberlandite (Rhodose) from Cumberland, R.

ilmenite and magnetite; white, olivine.
X30.
I.
Black
ECONOMIC GEOLOGY
524
Canada (85, 88)

Titaniferous magnetites have been found
number of localities in Ontario, those of the Chaffey and
Matthews mines being well known. Another large deposit
.
at a
occurs at St. Urbain, Quebec

Along the St. Lawrence River, in Saguenay County, Quebec
Where the sands
(88), magnetite sands are somewhat abundant.
.
have been worked over by the waves, the magnetite grains have
been concentrated into lenses distributed through the ordinary
Analyses of the sand,
sand.
etc.,
are given below:

INSOLU-
Crude sand
First concentrate
First tailings
...
Fe
TiOz 1
BLE RESIDUE
14.7
67.2
8.3
4.43
3.51
4.7
76.00
7.45
.006
.006
.043
.012
Soluble iron only.

number of titaniferous magnetite deposits
are found in Scandinavia. The best known is that of the Ekersund-Soggendal l
on the south coast of Norway, where the labradorite rock contains some
Routivare in northern Sweden has a large mass of spinellarge ore bodies.
bearing titaniferous magnetite in altered gabbro, while at Taberg in southern
Sweden is still another large deposit, which occurs in olivine-gabbro and was
recorded as early as 1806.
HEMATITE
This is by far the most important ore of iron in the United States,
having in 1914 formed over 90 per cent of the total production,
and about 85 per cent of the hematite mined came from the Lake
Superior region. It is also an important ore in some other countries.
Hematite may occur mixed with magnetite in magmatic
segregations (Kiruna, Sweden, page 517) and contact-metamorphic
deposits (29), as beds in sedimentary rocks (51-59), as replace-
ments
in limestone (page 548)

as irregular deposits formed by
circulating surface waters (page 525); and as specular hematites
in metamorphic rocks (page 525)
;
Distribution of Hematite Ores in the United States (Fig. 153)

At the present day there are but two very important hematite.
producing regions, in the United States, viz. the Lake Superior

and the Birmingham, Alabama, district. Other areas
which are worked will also be referred to, but they are less imregion
portant.
1
Vogt, Krusch u. Beyschlag, Ore Deposits, Translation,
I:
250, 1914.
IRON ORES
Lake Superior Region
(45, 47).
Under
525
this
great series of deposits lying in the region
and west
head are included a
surrounding the south
Lake Superior (47). The rocks are of remote

and the age and names of the iron-bearing formations
sides of
geologic age,
are as follows
Algonkian system.
Keweenawan
series:
Carries titaniferous gabbros in Minnesota but no
hematite.
Huronian
series:
Upper Huronian (Animikie group).

Biwabik formation of Mesabi.
Animikie group of Animikie district, Ontario.
Ironwood formation, Penokee Gogebic district,
Michigan and
Wisconsin.
Vulcan formation, Menominee and Calumet districts, Michigan.

Vulcan iron-bearing member of Crystal Falls, Iron River, and
Florence districts. Michigan and Wisconsin.
Gunflint formation, Gunflint Lake district, Canada, and Vermilion
district,
Minnesota.
Bijiki schist,
Marquette
district,
Michigan.
Deerwood iron-bearing member, Cuyuna
district,
Minnesota.
Middle Huronian. 1
Negaunee formation, Marquette
district,
Michigan.
Archaean system. 1
Keewatin series:
Soudan formation, Vermilion district, Minnesota.
Helen formation, Michipicoten district, Ontario.
Unnamed formation of Atikokan district, Ontario.
Several non-productive formations in Ontario.
The
detail,
ore-bearing districts have been studied in considerable

but the intervening parts are less well known, and it is
therefore difficult to correlate the
major geological units
of the
several districts.
The Archaean includes a complex series

Character of formations.
and basic igneous rocks, and two or more sedimentary formations, including the iron formations and slate of the Keewatin.
of acid
The Algonkian
includes four unconformable sedimentary series,
all
associated with igneous rocks, the entire succession being separated

by an unconformity from the Archaean below and the Potsdam
above.
The iron ores occur

1
as concentrations in the so-called iron forma-
The Lower Huronian and Laurentian, although
tions found in this region, do not carry
any ore
present in the series of forma-
bodies.
ECONOMIC GEOLOGY
526
tions,
which range in thickness from a few hundred to a thousand
feet.
In their present form these iron formations represent alterations

of chemically deposited sediments, such as cherty iron carbonates,
which are usually interbedded with normal clastic sediments such
as slate and quartzite.

In general terms the iron formations
may
be described as consisting
mainly of chert or quartz and ferric oxide, usually segregated into bands,
but sometimes irregularly mixed. Jasper is a banded rock of highly crystalline character with the quartz layers colored red.
Ferruginous chert differs
from it in being less crystalline, and with the quartz either banded or irregThis latter type is known as taconite in the Mesabi district.
ularly mingled.
Other phases of the iron formation are clay slates, paint rocks (alterations of
preceding), amphibole-magnetite schists,
ferrous silicate (greenalite), and iron ores.
cherty iron carbonate, hydrous
The
original iron rocks were cherty iron carbonate, ferrous

silicate, and pyritic iron carbonate, and unaltered remnants of
these are
still
found.
The average
iron content of all the original phases of the ironfor the region, excluding interbedded slates,
formations
bearing
is 24.8 per cent, and the iron ores, though of great commercial
importance, form but a small percentage of the rocks of the ironThis percentage varies from .062 to 2.00
bearing formations.
per cent.
The
iron ores are the result of subsurface alterations of richer
layers of the iron-bearing rocks, and are localized both where

these alterations have been most effective, and structural features
have served to
collect the
underground waters.
The
existence of ore then, depends largely on secondary conOf great importance in determining the distribution
centration.
of the ores are impervious basements
often shaped like pitching troughs.
and
fractures, the former
The ore bodies vary widely in their form, although steeply

dipping deposits are the rule, with the horizontally tabular ones
of the Mesabi range forming a marked exception.
The
ores of the
Lake Superior region vary from hard blue ores
They are mostly hematite with small quantibut some magnetite is known in the Marquette
to soft earthy ones.

ties of limonite,
district.
The following tables, taken from Van IJise and Leith, show the
average composition and range of Lake Superior ores. Many
IRON ORES
527
additional ones can be found in the reports on Mineral Resources

by the United States Geological Survey.
issued annually
AVERAGE COMPOSITION OF TOTAL YEARLY PRODUCTION OF LAKE SUPERIOR

IRON ORE FOR 1906 AND 1909
ECONOMIC GEOLOGY
528
TYPICAL ANALYSES OF LAKE SUPERIOR IRON ORES
CONTENT
IRON ORES
529
Upper and Middle Huronian, the latter being the more important. That of
the Upper Huronian is underlain by quartzite and covered by slate, while the
Middle Huronian iron formation is underlain by slate which in turn rests on
quartzites.
Igneous intrusions of Keweenawan age are common. The
structure of the range
is
that of a great east-west synclinal basin containing
>
FIG. 165.
Map
tion lines.
of
Lake Superior
(After
iron regions, shipping ports, and transportaLeith, U. S. Geol. Sura., Mon. LII.)
Van Hise and
number of minor folds, and while the ores occur on .both limbs of the basin,
they are most abundant on the northern one.
The ores may be divided into three classes, namely, (1) ores at the
a
base of the iron-bearing Negaunee (Middle Huronian) formation, (2) the

ores within the Negaunee formation, (3) detrital ores at the base of the
Goodrich (Upper Huronian) quartzite. Ores of the first and second
class are mostly soft hydrated hematite, while those of the third class are
hard specular ores with some magnetite from metamorphism due to
greater movements along the contact of the Middle and Upper Huronian
during the faulting within these rocks themselves.
While this carries iron formations in both
Menominee Range (39).
the Middle and Upper Huronian, only the former are commercially imThe iron
portant and are confined to the southern part of the district.
ores are mainly gray, finely banded hematite with lesser amounts of a
flinty hematite which shows local banding.
ECONOMIC GEOLOGY
530
FIG. 166.
FIG. 167.
Sections of iron-ore deposits in Marquette range.
(After
V an Hise).
Generalized vertical section through Penokee-Gogebic ore deposit and

Colby mine, Bessemer, Mich. (After Leith.)
adjacent rocks
Penokee-Gogebic Range
The
(42).
the iron formation being overlain
by
slate
ores occur in
Upper Huronian,
and underlain by quartzite and
ECONOMIC GEOLOGY
532
The latter is covered by a gabbro of Keweenawan age,

found in contact with the iron formation in places and has altered
black
slate.
which
is
and amphibole-magnetite rock.
Most of the iron formation,

The steeply dipping sedimentary rocks
ferruginous chert.
are cut by dikes of basic igneous rocks, thus forming troughs in which the
ores are concentrated.
Most of the deposits reached depths of 1000 feet
and upwards, but the horizontal extent is small. While soft hydrated
it
to jasper
however,
is
is the normal type of ore, still the hard slaty ore is not uncommon. Manganese is found in a few deposits.
Mesabi Range (44).
The rocks of this region are less folded and
metamorphosed, and dip slightly to the southeast. The iron formation,
which is mainly ferruginous chert, is overlain by a thick slate and underlain by a thin quartzite, which in turn rests on granite, or graywacke and
At the eastern enld of the range the iron
slate of lower Middle Huronian.
hematite
formation has been metamorphosed to amphibole-magnetite rock by a

gabbro intrusion. The iron-ore deposits are very irregular in shape, but
their horizontal extent is great as compared with their depth (Fig. 168),
most of them being less than 200 feet. The mining is done mainly by open
pits (PI.
XLV), and
the ore
is
a rather soft hematite of high grade.
serves the stratification of the original iron formation

grading into the latter.
and
It pre-
in places is
found
PLEISTOCENE.
FIG. 168.
Generalized vertical section through Mesabi ore deposit and adjacent

rocks.
Vermilion Range
folded and
(40).
The
(After Leith.)
chief
metamorphosed Keewatin
ore deposits occur in the highly

and the iron formation is
rocks,
The country rock

largely altered to jasper.
which the jasper occurs in basins or troughs.
mostly greenstones in
ores associated with
the jasper in these troughs usually have a greenstone footwall and consist of dense hard red or blue hematite, which is sometimes brecciated but
is
The
rarely specular.
This range lies to the southwest of the Mesabi

Cuyuna Range (48).
range and shows a series of small northeast-southwest anticlines in a
broad synclinal basin on whose northern limb the Mesabi range is situated, while on the southern limb we find the Penokee.
Owing to the
limited
number
the geology
-
is
of outcrops and lack of development at the present time,

not yet perfectly known, but the formations seem to include
quartzite and its altered equivalents, iron formations, slate, and intrusive
The ores form the altered and concentrated upper
granite and diorite.
PLATE XLVI
FIG.
1.
Iron mine, Soudan, Minn. Shows old open pit with jasper horse in middle.
FIG. 2.
View
of limonite pit near Ironton, Pa.
(H. Ries, photo.)

(533)
ECONOMIC GEOLOGY
534
parts of the steeply dipping iron-formation strata, which are exposed by

the erosion of the anticlines. The hanging wall is commonly chloritic
slate
and iron carbonate
in varying proportions and degrees of alterations,

either a quartz schist or amphibole-magnetite schist.
ore bodies thus far found seem to be in the form of lenses 100 to 250
while the footwall
The
is
feet thick, with their longer dimensions parallel to the highly tilted bedding of the series.
On the Canadian side of the boundary there are

Canada (79, 80, 81).
a number of iron-bearing areas (Fig. 165), only one of which is of importance,
Here the iron-bearing formation lies in the
viz. the Michipicoten district.
Keewatin, the geology and structure being similar to the Vermilion district of
Minnesota. The iron formation includes sideritic and pyritic cherts, jaspers,
siderite, schists and iron ore, and the Helen ore body lies in an amphitheatre
with iron carbonate on the east, ferruginous chert on the north, and tuffs on
the south, while a diabase dike crosses the basin.
The ore, which chemically resembles the hydrous Mesabi ores, dips eastward, apparently under the carbonate, but exploration below the latter has
developed a very large body of pyrite.

The origin of these ores has for years been a puzzling
to
Foster and Whitney considered them
problem
geologists.
while
Brooks
and
eruptive,
Pumpelly looked upon them as altered
Origin.
limonite beds.
The work
of
Van Rise and
Leith has shown us that the Lake
Superior ores were concentrated in certain sedimentary iron formations, and it was at first believed that these sediments were derived
of land areas containing much igneous rock.
Further study has led them to conclude, however, that the iron
formations have not only been derived in this way, but that the
iron has actually been contributed by greenstone magmas directly
from the weathering
to the water in
magmatic solutions and that there are all intermediate
stages between the two processes (41).

The iron ore as first deposited consisted essentially of chemically
precipitated iron carbonate or ferrous silicate (greenalite) with
some
ferric oxide, all finely interlayered
Later on,
with chert.
when
these sediments were uplifted to form the land

surface and exposed to weathering, the ferrous compounds, the
and greenalite, were oxidized to hematite and limonite.

While this occurred mainly in place, some of the iron was carried
off and redeposited elsewhere.
This resulted in a ferruginous chert
carrying less than 30 per cent jof iron.
Further concentration of the iron to 50 per cent or over was accomsiderite
complished mainly by the

ferruginous chert.
silica
being leached from the bands of
IRON ORES
Where the concentration
chemistry of the process
is
535
of the ore has occurred in troughs, the
thought to be as follows
Part of the ferric oxide was deposited as an original sediment containing silica and other impurities, or in some cases as sulphides or carbonates.
This was later enriched by the addition of iron carbonate. These were
originally contained in the rocks near the surface, and became oxidized
by percolating waters, which took up the carbon dioxide liberated, and
were thus able to dissolve iron carbonates or silicates, which they came
in contact with in their downward course toward the troughs in which the
ore
is
found.
The
precipitation of the ore was then caused by these solutions meeting with others which had filtered in by a more open and direct path from
the surface, and hence contained some free oxygen, which converted the
dissolved iron compounds into oxides.
The same solutions, carrying carbon dioxide, dissolved the alkalies out
of the basic igneous rocks, and these waters were then able to dissolve
silica.
In some cases the solution of silica proceeded faster than the
deposition of the iron ore, and made the rock quite porous. The general
was therefore a concentration of the iron and removal of silica.
result
processes have yielded mainly soft ores and ferruwhile

ginous cherts,
metamorphism has formed hard red and blue
brilliant
ores
and
specular
jaspers, as well as changed the iron for-
The weathering
mation into amphibole-magnetite

Most
schists.
found above the 1000-foot level, except in the

where the deposits are shallow, as compared with their
horizontal extent, some, however, being over 400 feet deep.
In the early period of mining many of the Lake Superior bodies were
worked as open cuts, but with depth underground working has been reThere are many deposits in the Mesabi district which are
sorted to.
worked as open pits from which the granular ore is dug with a steam
shovel and loaded directly on to the ore cars, which are run along the
working face (PL XLV).
The market value of the ores is based on the iron contents, percentage
of water, and amount of phosphorus, and -at times the manganese contents
Mesabi
of the rich ores are
district,
taken into consideration. Some objection was at first raised to the fine
character of the Mesabi ore and its tendency to clog the blast furnace,
therefore requiring the admixture of lump ore from the other ranges
but this objection has disappeared, and some furnaces now use over 75
per cent of Mesabi ore in their charge.
The Lake Superior iron ore region is not only the most important in
the world, but the production of some of the individual mines is startling.
is
The Mar(See production of individual mines at end of this chapter.)

quette range was developed as early as 1849, the Mesabi as late
as 1892, and the Cuyuna some years after this.
The total yield of
the Lake Superior region from 1854 to the end of 1914 has been 666,268,797
long tons. While the output has been phenomenal, and the supply large,
ECONOMIC GEOLOGY
536
high-grade ore
is
now
is
no longer abundant, and much ore running high
in silica
shipped.
Wyoming
(60).
Important deposits of hematite are found
schists at several localities in
in the
the Hart-
Wyoming,
pre-Cambrian
ville District, Laramie County, and near Rawlins, in Carbon County.
The Hartville deposits form a portion of the Hartville uplift,
which is a broad, low dome similar to that formed by the Black Hills,
and while the iron range extends from Guernsey to Frederick, a
distance of 8 miles, the productive area extends only from a point 2
miles northeast and
viz. in
mile southeast of Sunrise.
The pre-Cambrian sediments have been
folded into a complex

a
common
has
been
and
phenomenon, while
synclinorium,
faulting
the brecciation which accompanied both the folding and faulting
was an important structural factor in the ore formation.
The most important ore bodies are lenses occurring in the schist
along a limestone foot wall, the ore either replacing the schist or to a
lesser extent filling the joint, fault, and breccia cavities.
These
lenses range
the schists.
The
feet in length, and conform to the foliation of

Detrital ores derived from the foregoing are also found.
up to 1000
following geological section
Pleistocene
is
involved
IRON ORES
viz.
537
a hard gray hematite, and a soft greasy one of brown-red
color.
Siderite
and limonite are
of subordinate importance, while the
associated minerals are calcite, quartz, gypsum, chalcedony, barite,

The copper minerals occur in the fractures in the
chrysocolla, etc.
hematite.
Both types
of hematite grade into the schist, but
much
of the soft ore has been derived from the hard

Ball assigns an epigenetic origin to
by percolating waters.
the ore, believing that it was
deposited by descending waier, because (1) the ore is along zones of

maximum downward circulation, (2) lenses and veins are found along
from the main body, and (3) the associated minThe

erals, quartz, calcite, and limonite, are all water-formed ones.
magnetite and iron pyrite of the schist lying above the limestone footjoints at a distance
wall are regarded as the source of the iron.

During pre-Cambrian
times there was extensive erosion of this schist, and a downward
transferal of this iron by carbonated surface waters flowing along
the impervious limestone footwall, where it was precipitated by

oxygen-bearing waters coming by a more direct path.
Clinton Ore (51-59).
This
ore,
which
is
also called fossil, pea,
or dyestone ore, was given the first name on account of the ore bed
having been originally discovered at Clinton, N. Y. It is one of
the most persistent iron-ore deposits that is known (Fig. 169), for
it occurs at most points where rocks belonging to the Clinton
stage of the Silurian are found.
The following districts may be enumerated as showing the

location of the more important deposits: (1) west central New
York; (2) several narrow belts in central Pennsylvania; (3) Alleghany County, Virginia; (4) a belt through Lee and Wise
counties, Virginia, extending southwestward into the La Follette
district of Tennessee
(5) narrow belts in the region of Chat;
Bath
(6) Birmingham, Alabama;
(7)
and (8) Dodge County, Wisconsin. 1 Other
known occurrences of minor importance are indicated on the
map, Fig. 169, and in addition the ore has been recently discov-
tanooga, Tennessee;
County, Kentucky;
ered by drilling in Missouri.

Of all these districts, the Birmingham, Alabama, one
is
most important, with Chattanooga, Tennessee, and central

York ranking respectively second and third.
the
New
1
It has been recently shown that this area is not of Clinton age, but is older and
represents deposition in local, but connected basins of Maquoketa (Richmond)
time
(58a).
LEGEND
PLATE XLVII.
Geologic
(After Burchard,
map
of
Amer.
western half of Birmingham, Ala.,
Inst.
Min. Engrs.,
Bull. 24, 1908.)
district.
Mines
PLATE XLVIII.
Geologic
(After Burchard,
map
of eastern half of
Amer,
Inst.
Min.
Birmingham,
Ala., district.
Engrs., Bull. 24, 1908.)
(539)
ECONOMIC GEOLOGY
540
The Clinton
ore deposits occur as beds, or lenses, interstratwith shales and sandstones at different horizons in the
Clinton, and as many as three or four beds may be present
at any one locality.
They show extremes of thickness, rang-
ified
FOSSIL IRON ORES

IN
T.HE UNITED STATES
Map
FIG. 169.
of eastern United States,
iron ore. 1
showing areas of outcrop of Clinton
(After McCallie, Ga. Geol. Surv., Bull. 17.)
ing from a few inches to 40 feet, but rarely exceeding 10 feet.

The thicker beds often contain sandstone and shale partings,
and a
single
bed
is
sometimes traceable for miles along the
outcrop.
The
dip of the beds depends on the intensity of folding that

in any given area.
Thus the ore beds in New
has occurred
See footnote, page 537.
IRON ORES
541
li
1.
A Y
.
At RAN-
Ashland
Areas containing
workable, iron-ore
FIG. 170.
Map

or no workable Iron-ore
Areas containing possibly

workable iron-ore
Scale
1
20
15
i'ii
10
25
30
\poLPH
little
miles
showing outcrop of Clinton ore in Alabama.

Amer. Inst. Min. Engrs., Bull. 24, 1908.)
(After Burchard,
York State are nearly horizontal, and can at times be mined

for some distance from the outcrop by stripping; while those
found in the Appalachian region show a variable and sometimes
ECONOMIC GEOLOGY
steep
and hence require
dip,
to be
worked by underground
methods.
Two
ore,
textural varieties of Clinton ore are recognized, viz. (1) fossil
and
(2) oolitic ore.
The former is made up almost
entirely of a mass of fossil fragments,

while the latter consists of small, rounded grains of concretionary
character.
These two varieties may occur in the same or separate
beds.
Fiu. 171.
A
(2)
Outcrop of Clinton iron ore, Red Mountain, near Birmingham, Ala.

(Photo, from Tennessee Coal and Iron Company.)
second
hard
classification,
ore.
The former
based on grade, includes (1) soft ore, and

is found in the outcropping portion of the
to variable depths, sometimes as much as

400 feet, while the latter, which is usually sharply separated
from the former, occurs lower down. The soft ore runs high in iron
and silica, but low in lime, because this has been removed by weathThe hard ore runs high in lime, but low in silica and iron.
ering.
Both varieties are high in phosphorus and hence of non-Bessemer
seam and may extend
grade.
The great development of the BirBirmingham, Alabama (ol).

district
is
due
to
mingham
peculiar local conditions, for we find the
iron ores, flux, and fuel all in close proximity to each other (Fls.
XL VII, XL VIII).
IROX ORES
543
The Clinton
ore beds are found in Red Mountain (Figs. 170,

on the east side of the valley in which the city of Birmingham lies. There the Clinton formation, which is 200 to 500
feet thick and dips southeastward from 20 to 50, is composed
cf beds of shale and sandstone and includes four well-marked
iron-ore horizons, generally in the middle third of the forma171)
tion.
These beds are known as the Hickory, Ida, Big, and Irondale seams,
but there is difficulty in correlating them in different parts of the field.
Of these four beds the Big and Irondale are the most important. The
thickness of the former is estimated at from 16 to 30 feet, but the good
ore is rarely more than 10-12 feet thick, and at most places only 7 to 10
In the middle of the district, the bed is separated inio
feet are mined.
two benches by a parting along the bedding plane, or by a shale bed.
Either bench, though producing in one part of the district, may grade
into shaly low-grade ore in another part.
The following analyses are given by Harder (Min. Res. 1908), to show
the gradation from hard ore to soft ore.
ANALYSES OF CLINTON IRON ORE FROM ALABAMA
ECONOMIC GEOLOGY
MAP SHOWING
POSITION AND EXTENT
OF THE
OUTCROP OF THE
CLINTON FORMATION
IN
NEW YORK
Buffalo
i
!
I?.
Map
N T A R oc ;
CanandaiguaK 2
i
LWYOMING ]f
/LIVINGSTON.
ont
FIG. 172.
rT-o
1 Geneseo
K,TATLjHV
A _*fL\\ T
!
'j
qAr
CorninffoHCHEMUN^ OwegoJ
showing outcrop of Clinton ore formation in

(After Newland.)
New York State.
The following are analyses of the

Analyses of Clinton Ore.
Clinton ore from several localities, which serve more to show its
variation in character, than as types.
Alabama.
Others are given above under
IRON ORES
Origin of Clinton Ore.
siderable
discussion,
The
545
origin of this ore has created con-
and whatever theory
is
advanced,
it
must
(1) the fossiliferous character of

explain the following features
some beds, (2) the oolitic character of others, (3) the bedded
:
structure, (4) the soft non-calcareous ore at the surface,

hard or more calcareous ore at lower levels.
and the
The
three theories which have been advanced are the following

(1) original deposition, (2) residual enrichment, (3) replacement.
As can be easily seen, the correct solution of the problem is of practi:
cal value, since
it
indicates the possible extent of the ore body.
Residual Enrichment.
This theory supposes that the ore beds represent the weathered outcrops of ferruginous limestones.
That is to say,
the lime carbonate was leached out by surface waters down to the water
level, leaving the insoluble
trated form.
If this
theory
portion carrying the iron, in a more concenis correct, then the ore should pass into lime-
stone below the water level.

Russell (57),
who was an
earnest advocate of this theory, noted that

at Attalla, Alabama, the
Clinton limestone at a
depth of 250 feet from the

surface carried only 7.75
per cent of iron, while
at the outcrop it had 57
per cent of iron. These
figures
would
seem to
bear out this theory, but

Eckel (51) has recently
claimed that they must
._
rp
FIG. 173.
,
Typical profile of slope on Red Mountain,
Jf
be meorrect as th
hard
Shows bedded
starting on the iron-ore out-crop.
re
at
tlie de P th men character of ore.
(After Burchard, Amer. Inst.
tioned above carries 38
Min. Engrs., Bull. 24, 1908.)
to 42 per cent of iron.
Moreover, in none of the many fairly deep mines in Clinton ore has any
change to limestone been noted.
This supposes that the ores are of contemSedimentary Origin.
poraneous origin with the inclosing rocks, having been deposited on the
sea bottom as chemical precipitates.
This view was advocated at an early date by James Hall, who believed
that the iron came from the old crystalline rocks, which were leached of
.
,-,
their
iron
ocean
the oolitic ore being a chemical precipitate on the
floor.
Smyth
the ore.
talline
content,
(59) in
amplifying this theory agrees with Hall as to the source of
He points out that during Clinton times the drainage from the crysarea was carried into a shallow sea or basin. When the iron was
carried into these inclosed basins,
it was slowly oxidized and

precipitated,
gathering layer upon layer about the sand grains, thus forming oolitic ore.
ECONOMIC GEOLOGY
546
Where the ferruginous waters came in contact with shell fragments

the iron was precipitated around these, either due to a reaction with the
carbonate of lime in the shells, or more often by oxidation.
Later both
types of deposit became covered by ordinary sediments such as shales,
sandstones, or even limestones.
Additional evidence favoring a sedimentary origin is the continuation
of the ore with depth, some mines in Alabama being 2000 feet from the
Moreover some borings in Alabama have struck the ore \ to 1

outcrop.
mile from the outcrop and 400 to 800 feet below the surface. The occurrence of fragments of ore in the overlying limestone also points to the
ore being laid down before the lime rock.
McCallie
sedimentary
(54), after studying the Georgia ores, while admitting their

origin, believes that the original iron mineral was greenalite
or glauconite.
Replacement Theory.
much
This theory assumes that the ores were of
later origin than the inclosing rock, and were

of the lime carbonate by iron, brought in
formed by the replaceby percolating waters,

which had leached the ferruginous constituents from the overlying strata.
The structure of the formations, the comparative absence of iron in
the limestone overlying the ore, and restricted vertical range of the ores
ment
have been advanced as arguments against this theory.

Rutledge (58), however, as a result of his studies of the Clinton ores of
Stone Valley, Pennsylvania, concludes that they represent replacement deposits, and that the only part of the iron content which is of sedimentary
character is that contained in the siliceous concretions, most of the iron having come from the shale overlying the ore beds the hematite deposits have
thus been formed by replacement of limestone and concentration of the
ore.
The evidence presented in favor of this view is: (1) the invariable
association of the soft, rich ore with the leached decolorized shales, and of
the hard, lean ores with unweathered bright shales
(2) the relations of
;
the ^res to the shattered sandstones and to the topographic situation of

the ores
(3) the fact that analogous replacements are now taking place
;
in the
Medina
(4)
of the limestone to
the observed progressive steps in the transformation

ore, which may be followed in the field, in thin
an
sections, and in chemical analyses, and (5) the absence of conditions,

such as a local crumpling, including a shrinking of the strata, pointing to
a relative rather than an absolute enrichment of the ores.
In view of the fact that the advocates of the several theories often
bring apparently good evidence to support their case, one may perhaps
question whether several different methods of concentration have not
been operative. To the author, it seems that the sedimentary mode of
accumulation has probably been the dominant one in most cases.
Canada.
Wabana, Newofundland
(84).
The
ores
found
here are of a distinctly bedded character, being part of a series

of northwesterly dipping Ordovician sediments exposed for about
three miles along the north shore of Bell Island in Conception
Bay. The whole series extending from Lower Cambrian to Lower
IRON ORES
Ordovician
is
547
and consists of unbut in the upper thousand
several thousand feet thick,
metamorphosed sandstones and
shales,
been a concentration of ferruginous minerals.

Within the Lower Ordovician series, considered as equivalent
feet there has
to the British beds of Arenig to Llandeilo age, there are six zones,
containing beds of shale and sandstone alternating with oolitic
iron ore, and in one zone oolitic pyrite.
The iron ore is red brown,
massive, and breaks up readily into parallelopiped-shaped blocks,

the breaks being marked by minute veinlets of calcite and quartz.
Texturally the ore shows a number of concretions from -jV to i
inch diameter. These spherules are composed of alternating concentric layers of hematite
living boring algae.
and chamosite, which were pierced by

is locally abundant and may replace
Siderite
hematite, chamosite or even quartz.

The ore, which is of shallow-water orgin, and shows ripple-
marked
surfaces, is
thought to represent a chemical precipitate.
Iron brought into the sea from crystalline rocks on the land,
was precipitated by the oxidizing action of the algae, as ferric
oxide, some of which
to form chamosite.
monium carbonate
may have
The
given
reacted with aluminous sediment
was possibly formed by amas a decomposition product, below
siderite
off
the sediment surface.
The
oolitic pyrite represents
a deeper water formation, formed
presumably in the same way as the pyrite nodules now originating

in the Black Sea, viz. due to the action of hydrogen sulphide
The
liberated by bacterial action, reacting with iron salts.
ANALYSES OF CANADIAN IRON ORES
ECONOMIC GEOLOGY
548
Wabana
deposits are of great economic importance, the underground workings extending out under the sea.
Nictaux-Torbrook Basin, Nova Scotia (94)
An interesting
.
bedded Silurian ores is found in this belt lying between

the Devonian granites, and the Triassic area, of southwestern
Nova Scotia. The ore, which is interbedded with shales and
sandstones, dips steeply, and while it is chiefly hematite, it may
be locally changed to magnetite. Other bedded hematites of
similar age occur at Arisaig on the north shore.
series of
The hematite deposits of the Minas Geraes

some 300 miles from the coast, are among the largest
known iron deposits of the world. The iron series includes clay slates, subordinate limestone beds, and most important, quartzites (itabirite), the last
district of Brazil,
located
ranging from a nearly pure quartz rock with scattered flakes of hematite,
The ore forms lenses, often of tremendous
to massive quartz-free hematite.
size,
interbedded with the quartzite. The following analyses show the com(I), hard blue massive ore, and (II) thin-bedded ore.
position of:
Fe
69.35
63.01
II
.010
.184
Mn
Si
Al
.13
.15
.33
1.79
.16
1.53
CaO
MgO
Ign
tr
.03
.01
.31
.08
.01
.03
6.00
The iron-bearing formation is supposed to represent a sedimentary series,

the iron having been deposited originally as ferric hydrate, or possibly ferrous
carbonate. Subsequent metamorphism changed the iron to crystalline
gave some detrital deposits.
Other interesting and to some extent important hematite deposits are, the
2
replacements of hematite in limestone of Bilbao, Spain, the contact meta3
on
the
of
the
island
Elba,
replacement deposits of Erzberg
morphic deposits
in Styria, 4 and similarly formed hematites in Carboniferous and Silurian
heiratite, while later surface weathering
limestones of Cumberland and Lancashire, Eng. 5
LIMONITE
Limonite
(23, 23n,
62-73)
or
brown hematite,
is,
like magnetite,
United States as compared with hemaimportance

but
3.7
tite, having yielded
per cent of the total domestic iron-ore
in
in
other countries of the world it may
but
1914,
production
in the
of little
sometimes be of great commercial importance.

1
Leith and Harder, Econ. Geol., VI: 670, 1911; Derby, Iron Ore Resources of
World, Stockholm, 1910: 817; Harder, Econ. Geol., IX: 101,1914.
Vogt, Krusch u. Beyschlag, Lagerstatten II: 319, 1912.

Vogt, Krusch u. Beyschlag, Ore Deposits, Translation
4
Vogt, Krusch u. Beyschlag, II: 311, 1912.
2
3
Ibid. p. 317.
The name
iron oxides.
limonite
is
I:
369, 1914.
used here in a broad sense to include the different hydrous
IRON ORES
549
Limonites are rarely of high purity, mainly because of the fact

that they are frequently associated with clayey or siliceous matter,
but this can sometimes be separated to a large extent by washing.
Types
of Deposits
(23a, 626,
63a).
Limonite ores
may
occur under a
variety of conditions, and associated with different kinds of rocks, the

important types being as follows:
more
Residual deposits, consisting of residual clay derived from different kinds

by weathering processes, through which the limonite is scattered in
The deposits are usually
pieces ranging from small grains to large masses.
siliceous, except in those of a lateritic character (Cuba).
1.
of rocks
2.
Gossan deposits, derived usually from the weathering of sulohide ore

These may cap pyrite masses, or sulphides of other metals (many
bodies.
western ones).
Replacement deposits.
Bedded deposits, usually of oolitic character, and marine origin (Luxembourg). Here the limonite may have been precipitated as such on the ocean
bottom, or it was possibly precipitated as siderite or glauconite and later
3.
4.
changed to the
ferric hydroxide.
Bog-iron ores, representing deposits of ferric hydroxide precipitated in
bogs or ponds, the iron having been brought to the pond in solution. Ferrous compounds are more easily soluble than ferric ones, and the iron may
go into solution as sulphate, as bicarbonate in presence of an excess of CO2, or
5.
as soluble salts of organic acids.
The
be due
to: 1. Certain bacteria, which deposit ferric

oxidation of ferrous carbonate; 3. By precipitation of ferrous carbonate first as such due to loss of CO 2 and presence
of organic matter, the carbonate sometimes changing over later to the hydrox4. By change of ferrous sulphate to ferric hydroxide in presence of oxyide.
precipitation
hydroxide in their
may
cells;
2.
By
gsn, but the former might react with calcium carbonate, and yield siderite
with gypsum; or the sulphide may be derived from sulphate in presence of
decaying vegetable matter.

The ferric hydroxide is possibly precipitated first in colloidal form, and
changes later to a crystalline condition. Its precipitation in some localities
has been sufficiently rapid to permit gathering a supply from the pond bottom
every few years.
Distribution of Limonite in the United States
(13, 22o, 62-73).

Although deposits of limonite are widely scattered over the United
States (Fig. 174), about nine-tenths of the quantity produced cones
from
five states, viz.,
Alabama, Virginia, Tennessee, Georgia, and
Pennsylvania; indeed, the
first
supplied over 60 per cent of the
total output in 1914.
The residual limonites supply a large perResidual Limonites.

of
domestic
the
production, and have been formed (1) by
centage
the weathering of pyritiferous sulphide bodies (see gossan), or
(2) more often by the weathering of ferruginous rocks.
ECONOMIC GEOLOGY
550
FIG. 174.
Map
showing distribution of limonite and
siderite in the
United States.
(After Harder.)
Gossan deposits (16, 23a).

Limonite gossan ores derived from
the oxidation of pyrite, chalcopyrite, and pyrrhotite deposits
are found at a number of localities in the crystalline belt of
New England and
the southern Atlantic states, but they are of
limited importance at the present time.
One
belt
of historic
and former commercial importance is the " Great Gossan

Lead " found mainly in southwestern Virginia (23a), and traceable for over 20 miles,
deposit*
Hematite deposits
ED
Contact of crystalline rocks

.... r>_.
<_ _,
^
and
Palcoroic sediments
FIG. 175.
Map
its
Waêtirc
contents averaging 40 to 41 per cent
dcposi
Contact crf"crystai
and coastal plam de.
showing location of iron-ore deposits in Virginia.

U. S. Geol. Sun., Bull. 380.)
(After Harder,
PLATE
FIG.
FIG
1.
XLIX
(After McC alley, Ala. Geol.

Rept. on Valley Regions, Pt. II.)
Pit of residual limonite, Shelby, Ala.
Sun.
2.
Old limonite pit, Ivanhoe, Va., showing pinnacled surface of limestone
which underlies the ore-bearing clay. The level of surface before mining began
is seen on either side of excavation.
(H. Ries, photo.)
(551)
ECONOMIC GEOLOGY
552
metallic
iron.
(See also
Ducktown, Tennessee, and Copper
in
Virginia.)
Limonite gossan ores are not

sulphide deposits,
and many
of
uncommon
in
many
them carry more
of the western
or less
manganese
Uriskanj brown ora
Clinton tRockwood) formation
Clinton fossil
hematHa
Liberty Ball limes*
"ChickamaugaJ
ilurat Limestone
Vallej brown ore

(Blue Ridge district)
sKnox
Natural Bridge limestone<Nolithikjl
Homier-
"Buena Vista" shale Watauga)

(
Sherwood limestone (Shsdj)

Valley brown ore
(New RiTer district)
Lower Cambrian quartxt
Lower Cambrian quartzite and shale
Siliceous specular hematite
2000 Feet
FIG. 176.
Geologic section showing position of iron-ore deposits in Virginia.

(After Watson, Min. Res. Va., 1907.)
oxide, some, as those at Leadville, having sufficient to be used in

the manufacture of spiegeleisen. Their main use, however, is as a
flux in copper and silver smelting in the western states.
The most
important ones are in the Black Hills, South Dakota; Leadville,
Colorado; Neihart, Monarch, and Elkhorn, Montana; the Tintic
district, Utah; Tombstone, Arizona; and Pioche and Eureka,
Nevada.
Limonites in Residual Clays.
The other
class
of residual
IRON ORES
limonites has
many
553
scattered representatives, but the most im-
portant ones form a belt extending from Vermont to Alabama

(51, 71) and divisible into two groups, viz., the mountain and
the valley ores. In these the iron occurs as grains, lumps, or
masses scattered through residual clays, associated with CambroSilurian limestones, shales,
and
quartzites.
Vertical section showing the structure of the valley brown ore deposits
FIG. 177.
at the Rich Hill mine, near Reed Island, Va.
(After Harder, U. S. Geol. Surv.,
Bull. 380.)
ores are located in the eastern part of the Appalachian limonite belt, generally in the Blue Ridge or Appalachian
The mountain
least near their western edge.

valley ores are closely associated with them
there is no sharp line of separation between the two.
Mountains, or at
The
on the west, and

The two types,
however, present certain important differences.

Thus the mountain ores usually form relatively small, disconnected pockets in the residual material over the Lower Cambrian
at or near its contact with the overlying formation,
a
limestone, while other types of less common occurrence
usually
The valley ores, on the other hand, form more extensive
are known.
shallower
though
deposits in residual clay overlying limestones
quartzite,
above the quartzite.

In either case, however, the ore is not uniformly distributed
through the clay, so that individual pockets soon become worked out,
necessitating the finding of a new one.
(Fig. 177)
Mountain ores may extend to a depth of several hundred feet,

but the valley ores rarely exceed fifty feet in depth, and in neither
case do the deposits as a rule exceed 500,000 tons, the average being
ECONOMIC GEOLOGY
554
FIG. 178.
Va.
Section of fractured quartzite from residual limonite deposit, Pitt-sville,

Iron oxide deposited in part between grains and in part by replacement?
100,000 to 200,000. The ore may form from 5 to 20 per cent of

the clay and sand in different deposits or different parts of the
same deposit. Limonite and gothite are the two iron-ore minerals,
the higher grades carrying as much as 55 per cent metallic iron,
but the average shipments run about 45 per cent. The mountain
ores are usually poorer than the valley ones, and phosphorus
generally high enough to make the ore non-Bessemer.
The
show the percentage range

mountain ore, and II, valley ore:
following tables
(Harder) of
I,
is
of the chief constituents
IRON ORES
FIG. 179.
555
Section illustrating formation of residual limonite in limestone.
(After
Hopkins, Geol. Soc. Amer., Bull. XI.)
As the shale and limestones overlying the Cambrian quartzite

weathered, the iron oxide was set free, either by the decomposition
of ferruginous silicates, or of pyrite or siderite in the limestones.
This was then carried downward and concentrated
first in
the resid-
If weathering
ual clays of the limestone, forming the valley ores.
continued still deeper, the downward percolating iron solutions
reached the impervious quartzite, the ores (mountain type) becom-
ing concentrated in the clay overlying this, although some

deposited in crevices in the quartzite.
Oriskany Limonites
(23a)
was
These are so called because of their

To be more exact, they
limestone, under the
association with the Oriskany sandstone.

are found in the Lewistown (Silurian)
(Oriskany)
sandstone,
or
the
Romney
districts
ducing
in
(Devonian)
The main
shale.
proare
Alleghany County,
Virginia,
and central
Pennsylvania, but local

deposits are found at
the same horizon in
West
Ken-
Virginia,
tucky, and Ohio.
The
deposits
(Fig.
180) form replacements

in the upper portion
of the
stone,
Lewistown limeand may extend
along the strike for a

distance
miles.
FIG. 180.
Section of Oriskany limonite deposit.
(After Holden,
Min. Res. Va.,
1907.)
of
The
several
thickness
and depth are variable,

but in some cases may
ECONOMIC GEOLOGY
556
reach 75 feet and 600 feet respectively.
The formations
in
which
the ore occurs have been folded and the Oriskany removed from
the crests of the folds by erosion, so that the ore is found along
the outcrops on the flanks of the ridges.
The Oriskany ore resembles the mountain ore in texture, grade,
and impurities, but differs from it in forming larger and more continous deposits.
It
grades into limestone with depth.
Other Limonite Deposits.

In northwestern Alabama, western Kentucky, and Tennessee, limonite occurs in residual and sedimentary clays
1
Brown ore also occurs in the
overlying the Mississippian limestone.
Claihorne (Tertiary) formation of northeastern Texas (62/>, 65, 70), and Adjoining parts of Louisiana (622) and Arkansas. The ore forms horizontal beds
of slight thickness but
some
extent.
It is of little value.
In the Ozark region of Missouri and Arkansas (73), limonites are found
in residual clays over Cambrian limestone, but are of little economic
value.
Small deposits are known in Iowa
Oregon
(63),
Wisconsin
(62),
Minnesota, and
(16).
The brown
ores of the Appalachian belt are
much used by
pig iron
manu-
facturers because, owing to their siliceous character, they can be mixed with
high-grade Lake Superior ores which are deficient in silica. They are also
cheaper, and their mixture with other ores seems to facilitate the reduction
of the iron in the furnace.
The
analyses on page 557 give the composition of limonites
from a number
Canada
of different localities.
Bog iron ore has been obtained from deposits

Three Rivers District of Quebec, but its importance is
Some of the ore obtained at the Helen Mine (p. 534)
decreasing.
is quite strongly hydrated, but otherwise comparatively little
limonite is mined in Canada.
(4, 92).
in the

Limonite is obtained at a number of localities
but only a few need mentioning.
The so-called minettes 2 of Lorraine, Luxembourg, and Germany are of
in other countries (1),
great importance to the European iron industry. They represent great flat
lenses associated with shales, sandstones and marls of middle Jurassic age.
ore, which is chiefly limonite, with some admixture of calcite, is low
Other constituents
grade, its iron content ranging from 30 to 40 per cent.
include: P, 1.3-1.8 per cent; SiO2 7.5-33.6 per cent; CaO, 5.3-12.3 per cent.
The
iBurchard, U.
S.
154, 1907;
and Hayes and
Ulrich,
Geol. Atlas Folio, 95, 1903.

2
Cayeux, Minerals de fer oolitique de France, Paris, 1909; Iron
of the World, Stockholm, 1910.
Ore Resources
IRON ORES
Pi
557
ECONOMIC GEOLOGY
558
The theory of their origin is that the ore has been precipitated in sea water
directly as limonite, or first as siderite or glauconite and then oxidized.
Other oolitic bedded deposits may carry chamosite and thuringite, as those
of Thuringia and
Paleozoic rocks.
FIG. 181.
Section of oolitic iron ore (minette) from Luxembourg.
Cuba
Eastern
of these
Moa
Bohemia, or hematite as some European ones found in
X33.
contains three important districts of residual iron ore, two

in Oriente province, and a third, San Felipe in
and Mayari
province. The ore is in residual clay derived from serpentine,

and shows a dark red, earthy, surface zone occasionally containing shots
and lumps of solid brown ore and hematite, below which is yellowish or yellowish brown ore changing rather suddenly to serpentine.
The average depth
at Mayari is 15 feet.
The analyses indicate appreciable hematite and bauxite in the upper zone, while farther down hydrous iron oxides predominate.
We have here then a case of lateritic alteration.
Analyses of the surface ore I, and bottom layer II indicate the high grade
Camaguey
of these ores.
SiO 2
AhOs
Fe2 O 3
Cr2 O 3
2.26
7.54
14.90
4.97
68.75
64.81
1.89
3.66
FeO
NiO
.77
.74
1.49
2.75
MgO
1.50
comb.
11.15
12.75
SIDERITE
United States.
Siderite (74-78) is of little importance in the United
States, both on account of the small extent of the deposits (Fig. 174) and its
low iron content. When of concretionary structure with clayey impurities,
it is termed clay ironstone, and these concretions are common in many shales
and clays. In some districts siderite forms beds, often several feet in thick1
Kemp, Amer. Inst. Min. Engrs., Bull. 98: 129, 1915. (Has bibliography.)
Leith and Mead, Ibid., Bull. 103: 1377, 1915; and Ibid., Trans., XLII: 90, 1911.
IRON ORES
559
but containing much carbonaceous and argillaceous matter, and is known

This is found in many Carboniferous shales.
Iron carbonate in bedded deposits is found in the Carboniferous rocks
of western Pennsylvania, northern West Virginia, eastern Ohio, and northeastern Kentucky. These ores were formerly the bases of an important ironmining industry, but little is obtained now except in southeastern Ohio (16).
Concretions and layers of iron carbonate occur in the Cretaceous clays
ness,
as black band ore.
of
Maryland
(13)
and were formerly mined somewhat extensively in the

and Washington. Small deposits are also known in
vicinity of Baltimore
the Chickamauga (Ordovician) limestone of southwestern Virginia (23a).

In the western states iron carbonate nodules are found associated with
the Laramie (Cretaceous) formation in Colorado and northern New Mex-
but they possess no commercial value (16).

1
Earthy carbonates, occurring as beds, form the great
Foreign Deposits.
bulk of the British iron ore deposits. The most important ones are those
found in Mesozoic rocks, especially of the Yorkshire district. Others of less
importance occur in the Carboniferous. Considerable siderite has been
ico,
obtained from the Cretaceous limestones at Bilbao, Spain.
PYRITE
Pyrite is primarily used for sulphuric acid, but after driving off
the sulphur, the residue is sometimes sold under the name of
"
"
and used for iron manufacture, being mixed with a
blue billy
natural ore in the desired proportions.

The iron-ore mining industry in the
Production of Iron Ores.
United States has progressed with phenomenal strides, and this
country
now
leads the world in the production of iron ore.
so great has the production become that in 1903 it

combined output of Germany and Luxemburg
Indeed
was equal to the

and the British
Empire for 1902. Moreover, the average iron content

mined in the United States is higher than that mined
of the ore
countries, thereby resulting in the production of a greater

pig iron from a given quantity of ore.
amount
of
shown
in
The phenomenal growth

the following table:
DECADE
of the iron-mining industry
in foreign
is
560
65,000,000
60,000,000
55,000,000
50,000,000
O
o
45,000,000
*j
be
40,000,000
d
35,000,000
1h
30,000,000
25,000,000
20,000,000
15,000,000
10,000,000
5,000,000
IRON ORES
561
In the United States the Utah and some other western deposits
will no doubt be drawn upon, and many ores now looked upon as too
low grade to work will also be considered. Aside from domestic

sources of supply there are foreign ones which may perhaps be eventually turned to, such as those from Canada, Ne vfoundland, and
Brazil on this side of the Atlantic, or even those of Scandinavia on
the European side. Cuba, even now is sending considerable ore
to the United States.
PRODUCTION OF IRON ORES IN THE UNITED STATES FROM 1909-1914, BY

VARIETIES, IN
LONG TONS
562
ECONOMIC GEOLOGY
PRODUCTION OF LAKE SUPERIOR IRON ORE BY RANGES, 1904-1914, IN LONG
TONS
YEAR
IRON ORES
EXPORTS AND IMPORTS OF IRON ORE IN CANADA
563
564
ECONOMIC GEOLOGY
producing region. An accompaniment of this will ke the general adoption of

by-product coking, and Hayes points out that in certain furnaces now operating in the Lake Superior district the profit corresponds approximately to
the value of the by-products from the coke ovens.
The following table gives in condensed form the figures compiled by a
committee of the International Geological Congress (1). They are, because
of the difficulties involved in making estimates, to be regarded as only approximate, but they show enormous reserves nevertheless.
IRON ORES
565
S. Geol. Surv. Min. Res., 1908, I: 61, 1909.

and bibliography.) 17. Hice, Top. and Geol. Com.
17a. Lowe, Miss. Geol. Surv., Bull. 10,
(Pa.)
Pa., Rep. 9: 71, 1913.
1914.
18. McCreath, Sec. Pa. Geol. Surv., MM: 229, 1879.
(Miss.)
(Many analyses.) 19. Nitze, N. Ca. Geol. Surv., Bull. 1, 1893. (N.
21. Shaler,
(Ohio.)
Ca.) 20. Orton, O. Geol. Surv., V: 371, 1884.
(W. Va.)
16.
Harder, U.
(Brief re'sume' U. S.
22. Shannon, Ind. Dept.

Surv., New Ser., Ill: 163, 1877.
23. Smock, N. Y.
Geol. Nat. Res., 31st Ann. Rept.; 299, 1907.
(Ind.)
State Mus., Bull. 7, 1889.
(N. Y.) 23a. Watson and Holden, Min.
Res. Va., 1907: 402.
(Va.)
Ky. Geol.
24. Ball, U. S. Geol. Surv., Bull. 315: 206, 1907.

(Iron Mtn.,
(N. J.)
Wyo.), 24a. Bayley, N. J. Geol. Surv., Fin. Rep., VII, 1910.
25. D'Invilliers, Sec. Pa. Geol. Surv., D 3, II, Pt. I: 237, 1883.
(Berks
Co.) 25a. Graton, U. S. Geol. Surv., Prof. Pap. 68: 313, 1910.
(Fierro,
N. M.) 256. Harder, Econ. Geol., V: 599, 1910. (York Co., Pa.)
25c. Harder and Rich, U. S. Geol. Surv., Bull. 430: 228, 1910.
(Dale,
25d. Harder, U. S. Geol. Surv., Bull. 430: 240, 1910.
Calif.)
(Dayton,
Nev.) 26. Keith, U. S. Geol. Surv., Bull. 213: 243, 1903. (N. C.)
27. Kemp, Amer. Inst. Min. Engrs., Trans. XXVIII 146, 1898.
(Mine28. Kemp, U. S. Geol. Surv., 19th Ann. Rept., Ill: 377,
ville, N. Y.)
1899.
(Adirondack titaniferous ores.) 28a. Kemp, N. Y. State Mus.,
Bull. 149, 1911.
(Comparison pre-Camb., N. Y. and Swe.) 29. Leith
Magnetite.
and Harder, U. S. Geol. Surv., Bull. 338, 1908. (Iron Springs, Utah.)
Newland and Kemp, N. Y. State Mus., Bull. 119, 1908. (Adiron-
30.
31. Paige, U. S. Geol. Surv., Bull. 380, 1909.

(Hanover,
N. Mex.) 31a. Paige, U. S. Geol. Surv., Bull. 450, 1911. (LlanoBurnet region.) 32. Prescott, Econ. Geol., Ill: 465, 1908. (Heroult,
dacks.)
33. Prime, Sec. Pa. Geol. Surv., I: 19C, 1883.

Calif.)
(Lehigh Co.)
33a. Singewald, U. S. Bur. Mines, Bull. 64, 1913.
Econ. Geol., VIII:
336. Singewald, Econ. Geol.,
207, 1913.
(Titaniferous magnetites.)
VII: 560, 1912.

34. Spencer, Min. Mag., X:
(Cebolla dist., Colo.)
35. Spencer, U. S.
377, 1904.
(Origin Sussex Co., N. J., magnetite.)
36. Spencer, U. S. Geol.
(Cornwall.)
(Berks and Lebanon Cos., Pa.) 36a.
Surv., Bull. 315: 185, 1907.
Stebinger,
U.
S.
Geol.
Surv.,
Bull.
430:
329,
1914.
(Titaniferous
magnetite sandstones, Mont.) 37. Stewart, Sch. of M. Quart., April,

1908.
(Putnam Co., N. Y.) 38. Wolff, N. J. Geol. Surv,, Ann. Rept.
1893: 359, 1894.
(N. J.)
Like Superior District.

39. Bayley, U. S. Geol. Surv., Mon. XLVI, 1904.
(Menominee.) 40. Clements, U. S. Geol. Surv., Mon. XLV: 1903.
41. Clements, Smyth, Bayley, and Van Hise, U. S.
(Vermilion.)
Geol. Surv., 19th Ann. Rept., Ill: 1, 1898, and Ibid., Mon. XXXVI,
42. Irving and Van Hise, U. S. Geol. Surv.,
1899.
(Crystal Falls.)
10th Ann. Rept,, I: 341, 1889.
(Penokee.) 43. Lane, Can. Min.
(Mine waters.) 44. Leith, U. S. Geol. Surv., Mon. XLIII,
Inst., XII.
1903.
(Mesabi.) 45. Leith, Amer. Inst. Min. Engrs., Trans. XXXV:
454, 1904.
(Summary L. Superior Geology.) 46. Leith, Econ. Geol.,
II: 145, 1907.
(Cuyuna.) 47. Van Hise and Leith, U. S. Geol. Surv.,
Mon. LII, 1911. (General.) 48. Van Hise, Bayley and Smyth, U. S.
ECONOMIC GEOLOGY
566
Geol. Surv., Mon. XXVIII, 1897.

(Marquette.) 49. Weidman. Wis.
Geol. and Nat. Hist. Surv., Bull. 13, 1904.
(Baraboo.)
Clinton Ore.
50. Burchard, Tenn. Geol. Surv., Bull 16, 1913.
(E. Tenn.)
Burchard, Butts, and Eckel, U. S. Geol. Surv., Bull. 400, 1909.

(Birmingham, Ala.) 51a. Butts, U. S. Geol. Surv., Bull. 470: 215, 1911.
(Montevallo-Columbiana reg., Ala.) 52. Chamberlin, Geology of Wis53. Kindle, U. S. Geol. Surv., Bull. 285:
(Wis.)
consin, II: 327.
(Bath Co., Ky.) 54. McCallie, Ga. Geol. Surv., Bull.
180, 1906.
55. Newland and Hartnagel, N. Y. State Mus.,
(Ga.)
17, 1908.
56. Phalen, Econ. Geol., I:
Bull. 123, 1908.
(N. Y.)
660, 1906.
57. Russell, U. S. Geol. Surv., Bull. 52: 22, 1889.
(N. E. Ky.)
(Residual theory of origin.)
58. Rutledge, Amer. Inst. Min. Engrs., Trans.
XXXIX: 1057, 1908. (Stone Valley, Pa.) 58o. Savage and Ross,
51.
Amer. Jour. ScL, XLI: 187, 1916. (s.

Jour. Sci., XLIII: 487, 1892.
(Origin.)
Surv., Bull. 540: 338, 1914.
(s. e.
59. Smyth, Amer.

Wis.)
59a. Thwaites, U. S. Geol.
e.
Wis.)
60. Ball, U. S. Geol.,

(other than Clinton and L. Superior).
60a. Harder, U. S.
(Hartville, Wyo.)
Surv., Bull. 315: 190, 1907.
606. Jones, Econ.
(Eagle Mts., Calif.)
Hematites
61. Winslow, Haworth,

VIII: 247, 1913.
(Palisade, Nev.)
and Nason, Mo. Geol. Surv., IX, Pt, 3, 1896. Also Ref. 14. (Iron
(Va.)
Mtn., Mo.) 61a. Watson and Holden, Min. Res. Va., 1907.
Limonite.
62. Allen, Eleventh Report Mich. Acad. Sci., 1909: 95.
(Spring
Geol.,
Valley,
(n.
62a. Burchard, U. S. Geol. Surv., Bull. 620-G, 1915.

626. Burchard, U. S. Geol. Surv., Bull. 620-E, 1915.
(n. e.
63. Calvin, la.
Geol. Surv., IV: 97, 1895.
63a. Dake,
(la.)
Wis.)
La.)
Tex.)
Amer.
Inst.
tribution,
Min. Engrs., Bull. 103:

636. Diller, U.
ores.)
bog
1429, 1915.
(Formation and
dis-
S. Geol. Surv., Bull. 213: 219, 1903.
(Redding, quadrangle.) 64. Eckel, Eng. and Min. Jour., LXXVIII:

65.
(e. N. Y. and W. New Eng.)
Eckel, U. S. Geol. Surv.,
432, 1904.
Bull. 260:
66. Garrison, Eng. and Min. Jour.,

(Tex.)
348, 1905.
(Chemical characteristics.) 66a. Gordon and
258, 1904.
(E. Tenn.)
Jarvis, Tenn. Geol. Surv., Res. Tenn., II, No. 12: 458, 1912.
67. Hayes, Amer.
Inst. Min. Engrs., Trans.
(Car403, 1901.
LXXIII:
XXX:
Hobbs, Econ. Geol. II: 153, 1907. (Conn., N. Y.,

(Pa.
Mass.) 69. Hopkins, Geol. Soc. Amer., Bull. 11: 475, 1900.
Cambro-Silurian ores.) 69a. Jarvis, Tenn. Geol. Surv., Res. Tenn.,
70. Kennedy, Amer. Inst.
II, No. 9.
(Valley and mountain ores.)
Min. Engrs., Trans. XXIV, 258, 1894. (E. Tex.) 71. McCalley, Ala.
72. McCallie.
Geol. Surv., Rept. on Valley Region, II, 1897.
(Ala.)
Ga. Geol. Surv., Bull. 10, 1900. (Ga.) 73. Penrose, Geol. Soc. Amer.,
Bull. Ill: 47, 1892.
(Ark. and Tex. Tertiary ores.) 73a. Weld, Econ.
tersville,
Geol.,
X:
Ga.)
68.
399, 1915.
(Oriskany ores, Va.)
Lowe, Miss. Geol. Surv., Bull., 1912. (Miss.) 74a. Moore 3

Ky. .Geol. Surv., 2d ser., I, Pt. 3: 63, 1876. (Ky.) 75. Orton, Ohio
Geol. Surv., V: 378, 1884.
76. Second Pa. Geol. Surv., K:
(Ohio.)
77. Raymond, Amer. Inst. Min.
(Pa.)
386, and MM: 159, 1879.
(N. Y.) 78. Smock, N. Y. State MuEngrs., Trans. IV: 339, 1876.
Siderite.
74.
seum, Bull.
7:
62, 1889.
(N. Y.)
IRON ORES
Canada.
80.
81.
567
79. Bell, Ont. Bur. Mines, XIV, Pt. 1

278, 1905.
(Michipicoten.)
Coleman and Willmott, Ibid., XI: 152, 1902. (Michipicoten.)
Coleman and Moore, Ibid., XVII: 136, 1908. (Ranges east of
:
L. Nipigon.)
Coleman, Econ. Geol.
Mine.) 82. Coleman, Ibid., XVIII, Pt.
trict.)
83.
Hardman, Can. Min.
Inst.,
84. Hayes, Can. Geol. Surv.,

wick.)
85. Willmott, Can. Min. Inst., XI:
I:
521,
I:
151,
XI:
Mem.
106,
1906.
1909.
156, 1908.
78, 1915.
1908.
(Helen
lion
(Nipigon dis(New Bruns-
(Wabana, N.
(Titaniferous.)
F.)
86.
Lindeman, Mines Branch, No. 105, 1913. (Bathurst, N. B.) 87.

Lindeman, Ibid., No. 184, 1913. (Magnetite, Central Ont. Ry.) 88.
Mackenzie, Ibid., No. 145, 1912. (Magnetite sand, St. Lawrence Riv.)
89. McConnell, Can. Geol. Surv., Mem. 58, 1914.
(Texada, Id.) 90.
Miller and Knight, Ont. Bur. Mines, XXII, Pt. II, 1914.
(s. e. Ont.)
91. Moore, Econ. Geol., V.: 528, 1910.
(Bog ores Thunder Bay, Ont.)
92. Moore, Ont. Bur. Mines, XVIII: 180, 1909.
(Bog ore, English Riv.)
93. Warren, Amer. Jour. Sci., XXXIII: 263, 1912.
94. Wood(Que.)
man, Mines Branch, No. 20, 1909. (N. S.) 95. Young, Can. Min.
96. Young, Internat. Geol. Congr.,
488.
(N. B.)
Jour., XXXI:
Guide Book No. 1, 1913. (N. B.) 97. Young, Ibid., No. 7, 1913.
(Moose Mtn., Ont.)
CHAPTER XVI
COPPER
Ore Minerals of Copper.
Copper-bearing minerals are not only
numerous, but widely though irregularly distributed. More than
this, copper is found associated with many different metals and
under varied conditions.
Nevertheless but few copper-bearing minerals are important in
the ores of this metal, and the
tricts is
number
of important producing dis-
comparatively small.
The ore minerals of copper together with

and percentage of copper are as follows
tion
ORE MINERAL
their theoretic composi:
COPPER
569
Occasionally low-grade ores are found

which are self-fluxing, as those of the Boundary District of western
Canada. The introduction of pyritic smelting has permitted
the profitable treatment of low-grade pyritic-copper ores, even if
they carry no gold or silver. Complex ores of copper, lead, and
zinc sulphides are more costly to treat, but this expense may be
sibility of concentration.
more than made up
for
by
their gold
and
silver contents.
In the unaltered portion of the ore body the copper compounds

are mainly sulphides, but arsenides and antimonides are also
known.
In the gossan the copper occurs as carbonates, sulphates,
and more rarely as phosphates, arsenates,

and
vanadates.
antimonates
Quartz is the commonest gangue mineral,
Gangue Minerals.
are abundant in a few; barite, rhodoand
siderite
but calcite
are
also known.
Sericite is found in some
and
fluorite
chrosite,
in
so
is
tourmaline
certain
and
tin-copper and gold-copper
veins,
silicates, oxides, native,
ones.
which cause trouble in the reducmost objectionable, but bismuth,

though rare, is also very undesirable, but can be eliminated by electrolytic
Arsenic, antimony, tellurium, and selenium arc partially elimrefining.
inated in smelting, but must be completely removed by electrolytic
methods to make the copper pure enough for electrical work.
Tellurium is not uncommon in some districts, and renders the metal
red-short even in small amounts.
Silver, even if present in as small
amounts as .5 per cent, lowers the electric conductivity, and above 3 per
cent affects the toughness and malleability of the copper. Sulphur up to
.25 per cent lowers the malleability and .5 per cent renders the metal
cold-short, while .4 or more per cent phosphorus makes it red-short.
Metallic impurities may be present
Of these zinc is the
tion of the ores.
high percentage of
silica is
detrimental, as
it
requires too
much
basic
flux.
Occurrence and Origin.
Copper ores are found
in
many
formations ranging from the pre-Cambrian to the Tertiary, and

the deposits have been formed in many different ways. Indeed
some cases more than one mode of origin may be represented

by the deposits of one locality (Clifton, Ariz,; Bingham, Utah),
which makes it a little difficult to separate the different occurrences sharply on genetic grounds. Then too, a difference of opinion sometimes exists regarding the origin of some one deposit
in
(Rio Tinto, Spain)
A rough
grouping might therefore be
1.
Magmatic
2.
Contact-metamorphic deposits, in
made
as follows
segregations.
crystalline, usually gar-
ECONOMIC GEOLOGY
570
netiferous
limestone,
along
igneous
rock
contacts.
(Clifton-
Bingham, Utah, etc.)

3. Deposits formed by circulating waters, and deposited
fissures, pores, or other cavities, or by replacement.
Morenci,
Ariz.,
A.
B.
4.
By
By
in
ascending thermal waters.

waters, probably of meteoric character, and unassociated with igneous rocks.
Lens-shaped deposits of variable
origin in crystalline schists.
All cf these except the first have important representatives in

the United States, but in many cases their commercial value
depends on secondary enrichment and not the
mode
of
primary
deposition.
Superficial
Alteration
(2, 4,
11, 12,
14, 17,
18, 19).
This
may
produce results of great economic importance, and excellent

examples of it are seen in some of the Arizona ores, where the
upper portions of the copper deposits are brown or black ferruginous porous masses, brightly colored with oxidized copper minsuch as cuprite, malachite, azurite, and chrysocolla, while
below this at a variable depth they pass into sulphides.
In weathering, the copper minerals, such as chalcopyrite or other
erals
sulphides, are usually oxidized first to sulphates, and subsequently

changed to oxides, carbonates, or silicates, and occasionally even
concentration of the ore deposit may take place
to chlorides.
partly by segregation and partly

ore form, which are surrounded
by leaching, and pockets of the

by oxidized iron minerals form-
ing part of the gangue.

While the oxidation will not increase the total copper content
of the ore body, still it may change it into a more concentrated
form, for the carbonates and other oxidized copper minerals contain more copper than the original sulphide.
The ore in the
gossan may therefore run from 8 to 30 per cent or more, while

below it may show only 5 per cent of copper (see Penrose under ore
These altered ores cannot, however, be more
deposit refs.).
cheaply treated.
freed of
its ore,
If leaching follows oxidation, the gossan may be

as at Butte, Montana, where the upper part of
the ore-bearing fissures is poor siliceous gangue.

Below the zone of oxidation, there often lies a zone of secondary
sulphide enrichment (p. 481), of variable depth, followed still
lower down by the primary ore.
But even with secondary enrichment, the deposit may not
ECONOMIC GEOLOGY
572
carry more than 2 to 3 per cent of copper, and yet because of
its
be worth working.
concentrating possibilities
The processes of secondary enrichment have been referred to
on p. 481, and it was shown there that the work of Graton and
Murdock has demonstrated that the change is not as simple or
and
direct as
size
was formerly thought.
Importance
of
United States as a Copper Producer.
The
L, sets forth clearly the distribution of copper ores

in the United States, and statistics show the leading position of
map, Plate
country as a world's producer. The following table comby Butler shows in an interesting w ay the production of
copper according to the geologic age of the deposits.
this
piled
PERCENTAGE
IN 1913
Pre-Cambrian.
Jerome, Ariz.; Encampment, Wyo.

Paleozoic.
Ducktown, Tenn., and other Appalachian deposits
Mesozoic. Shasta County, Calif.; Foothills belt, Calif.; Ely,
Nev.; Yerington, Nev.; Alaska; Bisbee, Globe, and Ray, Ariz.;
Others
Tertiary.
Butte, Mont.; Morenci, Ariz.; Santa Rita, N. Mex.;
Michigan;
Bingham, Frisco and
Tintic,
15.60
1.60
36.71
45.98
Utah; Others
About 82 per cent of the copper produced in the United States in

1914 was obtained from four states, viz. Arizona, Montana, Utah
and Michigan, named in the order of their output, nearly all of
the rest coming from the Appalachians and Cordilleran region;
the ores of the latter are often worked chiefly for their gold contents,
with copper as a secondary product.
Magmatic Segregations
known
that copper sulphides may crystallize from

a magma, chalcopyrite being the best known example, still few
While
it is
cases of copper ores formed
Moreover,
it
is
sometimes
by rnagmatic segregation are known.

difficult to
prove definitely that the
deposit has originated in this manner, in other words whether

the copper sulphide has crj^stallized from fusion, or has been
deposited from solution.
The
criteria that
may
be used include:
primary intergrowths of sulphides and silicates, (2) inclusions

cf sulphides in silicates, (3) corrosion of silicates by sulphides, if
(1)
the latter crystallized later, and

effects.
(4)
absence of hydrothermal
Metamorphism may sometimes obscure the
characters of the ore bodv.
original
COPPER
573
The deposits of this class fall into two groups, viz. 1, those
representing crystallizations from the magma, with the sulphides
and silicates intergrown, and 2, bodies of comparatively pure
sulphides, which are believed by some to represent injections.
Those of the first group usually show pyrrhotite associated with
the chalcopyrite, the best
known example being
the Sudbury,
In the United States

Ontario, deposits (described under Nickel).
a small one has been described from Elkhorn, Mont., and another
from Knox County, Me. 1 Of greater interest, however, is an

occurrence found in Plumas County, California (48), where a
norite-diorite carries bornite, chalcopyrite and magnetite associated with the silicates in such a way as to leave little doubt of
their
magmatic origin.
Another interesting deposit
consists of
silicates in
is
found near Apex, Colo.
and
(50),
primary bornite and chalcopyrite, intergrown with

monzonitic dikes.
Of the injected pyritic deposits, the best known cases perhaps

are those of Roros and Sulitjelma, Norway, where great flat
lenses, carrying pyrite, chalcopyrite and pyrrhotite are found
in
metamorphic schists,
gabbro, and sometimes
doubted by some.
Others are
known
closely associated with

in
it.
at Bodenmais, Bavaria
Contact
metamorphosed
Their intrusive nature

2
may
be
and Falun, Sweden. 3
Metamorphic Deposits
Some of the most important copper deposits of the world

belong not only to this type, but are located in the United States.
It should be pointed out, however, that the ores of some of these
districts are not exclusively of this type, but include several
others which are closely associated genetically.
Moreover, while
in some cases il was the true contact-metamorphic ores that were
first
worked at some
of these localities, the other types are
now
There are included under

which
have the proper mincertain
this heading also
deposits,
no
associated
intrusive.
but
show
closely
eralogic characters,
or
Warren
District
Bisbee
States.
United
(32,
34, 37).
This district, which contains the famous Copper Queen Mine,
lies on the eastern slope of the Mule Pass Mountains (Fig. 183),
the important sources of production.
XVI:
124, 1908.
Journ. Geol.,
Weinschenk, Zeitschr. prak. Geol., 1900: 65.

Sjogren, Internal. Geol. Cong., Stockholm, 1910, Guidebook.
ECONOMIC GEOLOGY
574
but a short distance from the Mexican boundary. The section

that locality involves strata from pre-Cambrian to Cretaceous age, with an important unconformity between the Carbon-
at
iferous
FIG. 183.
and Cretaceous
Map
of Arizona,
(Fig.
185).
showing location
Prior to the deposition of
of
more important mining districts.
(After Lindgren.)
the latter the rocks had been broken by numerous faults (Fig. 184),
one of these, the Dividend fault, being specially prominent in
forming one boundary of the ore-bearing area.
This was followed
magma forming dikes, sills, or irregular

which
have
stocks,
metamorphosed the Carboniferous limestones,
by
intrusions of a granite
with the production of characteristic contact minerals.
COPPER
575
The Carboniferous limestone forms a shallow
basin,
which
is
cut through by the Dividend fault.

The principal ore bodies
lie around the porphyry stock, and along faults and fissures
where replacement of the limestone has occurred. Most of the
I
II
sill
e
>!
ECONOMIC GEOLOGY
576
ore has been developed in the Carboniferous and Devonian limethough in recent years important bodies have been dis-
stones,
covered in the Cambrian, and some even in the granite porphyry.

ore bodies form large, irregularly distributed, but rudely
The
The ore consists of malachite, azurite, cuprite,

oxidized
other
and
copper minerals above, which pass at variable
into
unaltered
sulphides; but between the two, or at least
depths
tabular masses.
Red nodular
shales with cross-bedded, buff,
tawnv, and red sandstones.
Cinlura formation, 1,800 feet
few beds of
plus uaknown'thickneas,
removed by erosion.
overlain by fluviatile Quaternary deposits.
.Mural limestone, 650 feet
Buff,
tawny and red sandstones and darkMorita formation 1,300 feet.
red shales, with an occasional thin bed of
impure limestone near
top.
beds of moderate thickness. Contains
Naco limestone, 3,000 feet

plus unknown thickness,
abundant
removed by pre-Cretacoous
Chiefly light-gray, compact limestone In
Cut by granite-porphyry
fossils.
Thick-bedded, white
&
light-gray, limestone
Contains abundant crinoid stems.
Cut by
granite-porphyry.
Dark -gray
Martin limestone, 340
fossiliferous limestone in beds of
feet
moderate thickness. Cut by granite-porphyry.

Thin-bedded, impure
cherty limestone!
Abrigo limestone. 770 .feet.
Cut 'by granite-porphyry.
Moderately thick, cross-bedded quartzites, with Bolsa quamite, 430 fet

basal conglomerate. Cut by granite-porphyry;
Great-unconformity.
,
Sericite-schists.
Cut by granite
an'd granite
pinal
porphyry.
500 1000
FIG. 185.
200U feet
Geological section at Bisbee, Ariz.
(After
Ransome, U. S. Geol. Surv.,
Prof. Pap. 21.)
never far from the
effects of oxidation, masses of massive or sooty

chalcocite are frequently found.
The primary ore consists of pyrite, chalcopyrite, with smaller
bodies of galena and some sphalerite, and was
deposited
metasomatic replacement
of the limestone.
the deposits usually contained too
As
by
originally formed,
little copper to make them

commercially valuable, but they have been subsequently enriched
by secondary enrichment. Large bodies of primary sulphides
of commercial grade have been
recently developed.
COPPER
577
The general relations of these ores to the intrusive porphyry and

the contact silicates indicate that they are of contact-metamorphic
origin.
In some cases an iron gossan has indicated an underlying- ore

many others do not outcrop.
body, but
LEGEND
SEDIMENTARY ROCKS
All\Mad Bands and grarels
Pinkard formation
Shales and sandstones*
partly metamorphosed)
limestones
and dolomites)
^Corallferous limestone,
tHeary-bedded
lowest member)
"Morenci formation
(upper shales)
lower urgillaceoua limestone)
formation
(cherty limestones
rngfellow
and lime
shales)
METAMORPHIC ROCKS
Contact metamorphic limestone

id shale of Paleozoic age
Contact metamorphic limestone now garnet, epidote

and magnetite
(mainly Modoc formation)
GEOLOGIC MAP OF THE VICINITY OF MORENCI,

ARIZONA
2000 feet
artz-monzonite-porpfayry
r
Faults
\/
FIG. 186.
Geologic
map
of vicinity of Morenci, Ariz.
Shafts
Drainage
(From Weed.)
In 1914 the average copper recovery of the Bisbee ores was

about 5.4 per cent and the average precious metals value about
$1.35 per ton of ore.
Clifton-Morenci District
(33).
The copper
deposits of this dis-
Morenci (Fig. 183) and Metcalf in eastern

Graham County. The ores were discovered in 1872, but remained
undeveloped for a long time because of the fact that they were of
too low grade, and too far from the railroads.
trict are located at
ECONOMIC GEOLOGY
578
At the present time, however, these large bodies

are utilized, most of the work being done by three
The
geologic section involves the following
of low-grade ore
large companies.
Quaternary (Gila) conglomerate.

Tertiary flows of basalt, rhyolites, and some andesites.
Cretaceous shales and sandstones. Several hundred feet thick.
Lower Carboniferous heavy-bedded pure limestones, 180 feet.
Devonian (?) shale and argillaceous limestone, 100 feet.
Ordovician limestone, 200 to 400 feet,

(?) quartzitie sandstone, 200 feet.
Pre-Cambrian granite and quartzitie schists.
Cambrian
Intrusions of granitic and dioritic porphyries of post-Cretaceous age

all the older rocks, forming stocks, dikes, laccoliths, and sheets.
pierce
All
these
of
faulted
by
rocks have been
bowed up and subsequently
late Cretaceous or early Tertiary
movements.
Copper Mt
FIG. 187.
Section in Morenci, Ariz., district.
ments; F,
fissure veins;
metamorphic
Jour.,
M, metamorphosed
P, porphyry; S, unaltered sedilimestone and shale; O, contact-
ores; R, disseminated chalcocite.
(After Lindgren, Eng.
and Min.
LXXVIII.)
Photo-micrograph showing replacement in Clifton-Morenci ores. Dark

gray chalcocite, developing by replacement of pyrite (light gray). The chalco-
FIG. 188.
accompanied by small amounts of microcrystalline quartz, sericite shreds,

Black areas represent open field. (After Lindgren, U. S. Geol. Sun.,
Prof. Pap. 43.)
cite is
and
kaolin.
COPPER
579
Briefly stated, the distribution of the deposits of copper (Fig.

187) ore is practically coextensive with a great porphyry stock
and
dike systems, the deposits occurring either in the^poror

close to its contact, as well as along dikes of porphyry
in
other rock.
some
phyry
its
The original ores were pyrite and chalcopyrite, of too low grade
to be workable, but they have since become so by a process of
secondary enrichment. No ores were formed before the porphyry
intrusion.
Where the
with the granite and quartzite,
latter is in contact
sw
Feet abort gel level
Old Blue shaft
/^
Manganese
Blue Mine
C?W'?
NE
Detroit Mine
Detroit Shaft
(projected)
South'Shaft
Elev.48M
Elev.4884
ft.
ft.
Ordovician
limestone
Elev.4488
.?
FIG. 189.
tact
No
Cp F^
E'-.4459
QrF?
ft.
Vertical section of ore body in Clifton-Morenci district, showing conmetamorphosed limestone. (After Lindgren, U. S. Geol. Sure., Prof. Pap.
43.)
little change is produced, but where the porphyry is found

adjoining the limestones or shales, extensive contact metamorphism
developed, resulting in the formation of large masses of garnet and
but
epidote, especially in the Lower Carboniferous limestones.

Where alteration has not masked the phenomena, magnetite,
chalcopyrite,
minerals.
pyrite,
and
zinc
blende
accompany the contact
ore bodies in the limestone are often irregular, but more

frequently roughly tabular, because of the accumulation of the
The
minerals along the stratification planes, or walls of dikes.

In many parts of the district the copper occurs in fissure veins
which cut porphyry, granite, and sedimentary rocks, and were
ECONOMIC GEOLOGY
580
probably formed shortly after the consolidation of the porphyry.

These in the lower levels carry pyrite, chalcopyrite, and sphalerite,
but no magnetite. Surface leaching of these veins has often left
limonite-stained, silicified porphyry outcrops.
Accompanying these veins, and of more importance commercially,
These
are often extensive impregnations of the country rock.
disseminated deposits in the highly altered porphyry are leached

out above, but lower down show a zone of pyrite and chalcocite,
which does not usually extend below 400
Most
feet.
of the copper in the district is obtained

ores containing chalcocite in altered porphyry.
from concentrating
In 1914 the yield
of copper from the concentrating ores was 1.65 per cent, while
the smelting ores gave an average yield of 4.7 per cent.
The precious metal content is so low that much of the output
of this district
is
not refined electrolytically unless the copper
is
not pure enough to put on the market.
The intrusions of porphyry produced strong contact metamorphism in the shales and limestones of Paleozoic age, resulting in the
contemporaneous and metasomatic development of various contact silicates and sulphides, 1 the contact zone thus receiving
additions of iron, silica, sulphur, copper, and zinc, substances unknown in the sedimentary series away from the porlarge
phyry.
Subsequent to the solidification of the porphyry, extensive

fissuring occurred in both it and the sediments, resulting in the
deposition of quartz, pyrite, chalcopyrite, and zinc blende in the
fissures and by replacement of the wall rock.
These are low in
but
there
is
a
close
relation
between
the
veins
and contact
copper,
of
because
the
of
their
metallic
deposits
similarity
contents, and
tremolite and diopside where
extensive impregnation of the
porphyry also occurred at this time. Subsequent exposure of
the deposits by erosion permitted the entrance of surface waters
which was followed by weathering and secondary .enrichment.
of the
similar
development of
limestone forms the wall.
Bingham Canon, Utah
The
(101, 102).
This camp, which
is
the
leading copper-producing locality of Utah, is situated in the northcentral part of the state, on the eastern slope of the Oquirrh
Mountains, 20 miles southwest of Salt Lake City.
The
1
rocks of this area include a great thickness of Carbonif-
Garnet, cpidote, diopside,
etc., pyrite,
magnetite, chalcopyrite and sphalerite.
ECONOMIC GEOLOGY
582
erous sedimentary formations, which are divisible into a lower

member of massive quartzite with several interbedded limestones,
and an upper member of quartzite with black calcareous

sandstones, and limestones.
FIG. 190.
Thin section
of altered porphyry,
taining grains of pyrite
from Clifton-Morenci
surrounded by chalcocite (both black).
shales,
district,
con-
X18.
The sediments, though showing in general a northerly dip, and

northeast-southwest strike throughout the region, vary in their
from east-west on the western slope to north-south on the
eastern, so that they form a synclinal basin, with northward
strike
pitch.
The whole series of sediments, but especially the lower member, is

pierced by an igneous intrusion, forming dikes, sills, and laccoliths.
Prominent among these are two large areas of monzonite, one forming an irregular laccolith, the other a broad irregular stock. An
extensive latite flow, outcropping on the eastern slope of the ranges,
covered some of the sediments and older intrusives.
There has been fissuring at several different periods following the

igneous intrusion, but in most cases displacement along these fractures does not exceed 150 feet.
The northwest-southeast fissures
carry the most important lead-silver ores.
The limestones of the lower member, averaging 200 feet in thickness,
have been highly marbleized, and carry large bodies of copper
PLATE LII
FIG.
1.
Smelter of Arizona Copper Company, Clifton, Ariz.

Mag., X.)
FIG,
2.
View
of
Bingham Canon, Utah.

Pap.
(After Keith,
(After Church,
Min.
U. S. Geol. Surv., Prof.
38.)
(583)
ECONOMIC GEOLOGY
584
and the calcareous carbonaceous shales of the upper member

sometimes carry it as well.
ore,
In many cases
Two types of
the ore
is
closely associated with the intrusives.
(1) great
copper deposits are recognized, viz.
tabular replacement masses in limestone, lying roughly parallel with
the bedding, and showing sometimes an extent of several hundred
:
feet along the strike, as well as a thickness of even 200 feet; (2) disseminations in a large monzonite laccolith, especially in the fractured,
fissured,
and altered portions
of the same.
The contact replacement
deposits have been important ones in

the past, but the enormous bodies of low-grade disseminated ore in
the monzonite are now the most important (PI. LI).
The limestone
primary pyrite and chalcopyrite,

and tetrahedrite. Quartz is
by
gangue mineral, but as might be expected in a contact
ores consist
enriched in some cases

the chief
of
chalcocite
deposit, garnet, epidote, tremolite, specularite, pyrrhotite, sphalerite,

galena, etc., are also present.
The primary ore of the disseminated type consists of grains
and veinlets of pyrite and chalcopyrite, distributed through both
FIG. 191.
Section showing replacement of limestone by pyrite (P) and chalcocite

Quartz (Q). (After Boutwell, U. S. Geol. Surv., Prof. Pap. 38.)
(Ch).
COPPER
585
shattered and altered monzonite porphyry and quartzite. The

commercial ore is due to secondary enrichment, and the zone
it
containing
and
thickness
and
underlies the leached or partly leached capping,

primary ore. In this ore zone, whose average
overlies the
about 165
is
feet,
the secondary sulphides are covellite

thickness of the capping was 115
The average
chalcocite.
feet.
The theory
quartzites
of origin advanced by Boutwell is that the

and limestones were intruded by the monzonite in
Mesozoic or early Tertiary times, producing contact metamorphism of the limestone and replacing it with sulphides.
After the upper portion of the monzonite intrusion was partly
by northwest-southeast
cooled, the inclosing rocks were fractured
fissures, along which there ascended heated aqueous solutions from

the deeper, un cooled portions of the magma. These solutions not
only altered the fissure walls, but deposited additional metallic
sulphides, thus enriching the limestones as well as altering the
monzonite by the addition of copper, gold,
silver, pyrite,
and
molybdenite.
In 1914 the ore treated at the mills of the Utah Copper Company
had an average copper content of 1.425 per cent, with an average
recovery of 66.04 per cent.
This district, although of recent developEly, Nevada (79, 81).

ment, promises to become of great importance. The copper belt,
which lies 6 miles west of Ely, in White Pine County (Fig. 232), is
about one mile wide and six miles long extending in an east-west
direction.
It lies in a pass through the

route to Eureka, Nevada.
The
Egan Range, along what used to be a
section there involves the following formations:
Ruth limestone
Arcturus limestone
Ely limestone, Carboniferous

White Pine shale \ _
AT
j if Devonian
Nevada limestone
1000 feet
1500 feet
1000 feet
m/v\rfeet*
1000
The sediments which have a gentle dip are
cut
by a coarse-grained
quartz monzonite, which has effected only a limited amount of

alteration in the adjacent limestone, producing some garnet rock
and chalcopyrite.
There are present also dikes of porphyry and rhyolite lavas, the
On property of Utah Copper Company.
1
ECONOMIC GEOLOGY
586
latter resting
on the uneven limestone surface
(Fig. 192),
but these
eruptives bear no genetic relation to the ore.

Of importance in this connection are the monzonite intrusions,
which carry
The
ore.
ore, consisting of pyrite
and
chalcocite, is
disseminated through the much altered and shattered monzonite

porphyry and there is a sharp line of separation between the gossan
and unoxidized bluish white rock containing the grains of pyrite

and chalcocite. The oxidized zone on the average extends to a
FIG. 192.
Section of Ely, Nev., district.
(From Weed.)
depth of 100 to 150 feet, while a thickness of ore ranging from

190 to 280 feet has been determined.
Some of the ore bodies are of great size, that at the Ruth mine
having a width of 50 to not less than 250 feet, and being developed
for a length of not less than 900 feet.
Lawson believes that the ore bodies have resulted from a leaching of secondary ores in the oxidized zones and that the only
primary ore now known is the chalcopyrite in the garnet rock
occurring beneath the quartz
"
blouts."
These
latter are
of quartz occurring mainly along the contact, and formed

replacement of both limestone and porphyry with silica
was leached out
masses
by the
which
porphyry by carbonated waters.

The ores are worked in part as open cuts (PL LIII, Fig. 2),
and the average copper content of those mined in 1914 was
of the
1.483 per cent.

Other Deposits.
Among the other deposits, yielding copper ores in part
or wholly of the contact metamorphic type may be mentioned those of the
following districts; Santa Rita, N.
Bell,
Ariz.
(40).
The
first
named
M.
(85); Yerington, Nev. (78, 80); Silver

of these is becoming important chiefly
on account of its great disseminated deposits in highly altered and shattered

sedimentary and intrusive rocks, in which the copper occurs largely native
or as the oxide, although chalcocite is by no means uncommon.
PLATE LIII
FIG.
1.
View looking northeast from the Eureka ore pit of the Nevada Consolidated Copper Company, Ruth, Ely district, Nev. (D. Steel, photo.)
2.
South end of the Eureka ore pit, Ruth, Nev. The hills in the background are limestone at the top and porphyry at the base. (D. Steel, photo.)
FIG.
(587)
ECONOMIC GEOLOGY
588
Alaska.
Ketchikan District
(26,
28).
The most important
ore bodies are contact-metamorphic ones occurring in irregular

masses from 10 to 250 feet in dimensions, along the contacts of
the intrusive rocks, usually with limestones, the ore composed
mainly of chalcopyrite, magnetite, pyrrhotite, and pyrite in a

gangue of amphibole, orthoclase, epidote, garnet, and calcite.
FIG. 193.
Geologic
Alas.
map
of
Copper Mountain Region, Prince
of
Wales Island,
(After Wright, U. S. Geol. Surv., Butt. 379.)
In addition to these there are lode deposits in shear zones, vein

deposits in fissures, and disseminated ores.
The ores mined are somewhat low in grade, with a little gold and
silver, but high in iron and lime, and form a desirable flux for
Tacoma and British Columbia.

At Copper Mountain in the Hetta Inlet
smelters of
district (Fig. 193) the
ores are (1) contact deposits occurring between granite
and lime-
PLATE LIV
FIG.
View from open cut of Old Dominion mine, Globe, Ariz., looking towards
Rocky surface beyond tank, weathered dacite; low ridges beyond
1.
Miami.
creek, Gila conglomerate.
(H. Ries, photo.)
p.
'
':'&>?*
=
Open cut, Mother Lode mine, near Greenwood, Brit. Col. Right wall,
limestone; left wall, contact metamorphosed rock.
(H. Ries, photo.)
FlG. 2.
(689)
ECONOMIC GEOLOGY
590
stone or schist, and (2) vein or shear zone deposits, occurring

along the bedding planes of the greenstone schist and quartzites.
The contact zone
is
of variable
118).
Boundary
width and
is
broadest in the
limestone.
Canada
Copper
(117,
ores,
which
in
District, British
many respects
Columbia.
possess the characteristics of
contact-metamorphic deposits, are

found in the Boundary District of
southern British Columbia. In the
Phoenix area the geologic section
a S
involves the following formations
Pulaskite
Tertiary.
augite
flows;
porphyrite
porphyry,
and
trachyte
conglomerate, sandstone and
shale.
Jurassic.
Granodiorite;
a bath-
olith, probably underlying Phoenix.

Carboniferous. Rawhide forma-
tion.
Argillites.
Brooklyn formation, with: (1)

Mineralized zone of garnet,
epidote and ore; (2) zone of
jasperoids, tuffs, argillites and
altered basic intrusives; and
~
IS
(3) crystalline
Knob
Hill
breccias,
with
II LI
limestone.
group.
Massive
and cherts,
and limestone.
tuffs,
argillites
disturbances have
obscured the relationships of
Crustal
- 3
2 's
the different formations.
The
lenticular ore bodies
lie
in
in the jasper-
basin-shaped troughs
oid zone and crystalline limestone
(Fig. 194). The average ore, which
to 1.6 per cent copper, and the
1.2
from
self-fluxing, ranges
metallic minerals, which are disseminated through the gangue,
along fracture and cleavage planes (Fig. 195), consist of chalcoThe gangue
pyrite, pyrite, specular hematite and magnetite.
minerals are epidote, garnet, actinolite, quartz, calcite and chlorite.
is
COPPER
591
At Deadwood (117) the geological formations and ores are

similar to those occurring at Phoenix.
Fig. 196 shows a section
FIG. 195.
Thin section
across the
of crystalline limestone containing branched veinlet of

X33.
sulphides, from Phoenix, B. C.
Mother Lode
ore
body
at
Deadwood.
The
consists of a massive mixture of chalcopyrite, pyrite
ore here
and mag-
Section through Mother Lode ore body at Deadwood, B. C. O, ore;

C, crystalline limestone, Brooklyn formation; Cl, mineralized contact metamorphic zone of C; Gd, granodiorite; Khl, Knob Hill group, chert tuff zone;
Kh2, Knob Hill group, jasperoid tuff zone; G, clay, sand, gravel. (After
Le Roy, Can. Geol. Sum., Mem. 19.)
FIG. 196.
and uniformly distributed along fracture and cleavage planes in the gangue minerals, which consist chiefly of contact
netite, finely
silicates.
and
The
ore carries 1.1-1.3 per cent copper,
silver per ton.
and $1.00 gold
ECONOMIC GEOLOGY
592
These deposits are located

Whitehorse, Yukon Territory.
in southern Yukon Territory.
They consist of contact metamorphic deposits in Carboniferous limestone near its contact with a
Mesozoic granite. The chief ore minerals are bornite and chalcopyrite,
with
occasional
tetrahedrite
and
chalcocite.
Iron
sulphides are not abundant, but iron oxides are common and may
form separate masses. The non-metallic gangue is chiefly andra-
The general average of

augite, tremolite and calcite.
copper contents is 4 per cent, and gold and silver are present, but
not in large amounts (119).
dite,
The copper deposits of Cananea, which are in part of the conmetamorphic type, are well known. They have been developed in Paleozoic limestones, by the intrusion of diorite porphyry and granodiorite, and
carry chalcopyrite, sphalerite, bornite, magnetite, hematite and galena, in a
gangue of contact silicates. Of greater importance, however, are the lodes
and disseminations in sericitized and silicified diorite porphyry. Other
2
3
4
interesting deposits occur at San Jose, Matehuala and Velardena.
Mexico.
tact
Deposits Formed by Circulating Waters

This grouping includes deposits of the fissure vein or related
types which have been formed by cavity filling or replacement,
and is further subdivided into: (A) those deposited by ascending
thermal solutions, evidently of magmatic origin, and (B) those
deposited by waters, probably of meteoric character, and unassociated with igneous rocks.
A. Deposits
Formed by Ascending Thermal Waters
This group includes copper ore bodies formed in the lower

vein zone, and those deposited at intermediate depths.
Lower Vein Zone.- Copper veins or lodes carrying tourmaline
as a high temperature index mineral have been described from a
In the United States the most important
of localities.
number
deposit is that found in the Cactus mine of southern Utah. This

a low-grade chalcopyrite-pyrite ore containing tourmaline and
occurring in a brecciated area of sericitized and tourmalinized
is
lEmmons, S. F., Econ. Geol., V: 312, 1910.

2
Kemp, Amer. Inst. Min. Engrs., Trans. XXXVI:
178, 1905.
Spurr, Garrey and Former, Econ. Geol., VII: 444, 1912.

<Spurr and Garrey, Ibid., Ill: 688, 1908.
1
COPPER
593
Other deposits are known at Copperand Meadow Lake, 2 Calif.

In Canada, a somewhat important example of this type occurs
at Rossland, Brit. Col. (115).
Here the Carboniferous sediments
have been cut by a series of extrusives and intrusives ranging
from Triassic to Tertiary in age, with several periods of deformation and two of mineralization.
The ores occur as replacements
fissures
and
sheeted
zones, chiefly in the augite-porphyrite
along
and monzonite, with pyrrhotite and chalcopyrite as the ore minpost-Paleozoic monzonite.
opolis, Ore.,
erals in a
gangue of altered country rock. Hydrothermal alteris marked, the high temperature conditions
indicated
the
being
by
development of biotite, and also some
wollastonite
and epidote.
tourmaline, garnet,
The values run about .7-3.6% Cu; .4-1.2 oz. Au; and .3-2.3
ation of the wall rock
oz.
Ag.
Deposits
of
the
Intermediate Vein
Zone.
These consist
usually of deposits of the fissure vein type, but sometimes form

disseminations, etc. They include a large number of very
important deposits.
The mining camp of
United States.
Montana (70-77)
Butte is of importance and interest both on account of the size
and extraordinary richness of its deposits, all of which have
combined to make it the greatest copper-producing camp of the
.
world.
Up
to
August,
1913,
it
had yielded
in
round
numbers,
6,000,000,000 pounds copper; 260,000,000 ounces gold 1,250,000

ounces silver; and a large but not definitely known tonnage of
;
zinc (74).
lies on the western border of the Boulder batholith, the
having a width of 75 miles and a length of over 100 miles.
Lying between the main range of the Rocky Mountains on the
east, and the Bitterroot Mountains on the west, the batholith
seems to have been intruded in the Eocene (?) after a period
of folding and thrust faulting, and without causing any doming.
Associated with the batholith are a number of fissure veins,
one type of which is found only in the Butte district, and thereThe rocks of the Butte district include:
fore concerns us here.
or
Granite
(1)
quartz monzonite, the Butte granite, much jointed,
Butte
latter
and hence permeable to

1
solutions;
Lindgren, U. S. G.
Lindgren, A. J. S.,
S.,
(2) Aplite, in irregular
22d Ann. Kept., Ft.
XLVI:
201, 1893.
2, p. 551.
bodies
ECONOMIC GEOLOGY
594
Pal - ALLUVIUM AND WASH PLEISTOCENE
SILVER VEINS
COPPER VEINS
Nrl - INTRUSIVE RHYOLITE NEOCENE
ap
APLITE
POST CARBONIFEROUS
9''- GRANITE
FIG. 197.
Map
of eastern part of Butte, Mont., district, showing distribution of

veins,
and
and geology.
(U. S. Geol. Surv.)
dikes, especially in the northwestern portion of the district;
Quartz porphyry dikes, roughly parallel in an east-west

direction, and following the earliest vein system; (4) Hhyolite,
of intrusive and extrusive character, especially in west and northwest part of district, its offshoots cutting both the copper and silver
(3)
veins; (5) Andesite, of pre-Tertiary age

to the ores.
and bearing no
relation
COPPER
595
The granite is cut by many faults, which are hard to detect,

and which are often mineralized. Fissures are common in the
batholith, and there are two main series, striking east-west, and
northwest-southeast, corresponding broadly to the two most
important fracture zones of the

district.
There have been identified
six
distinct fissure systems, which cut
the granite,
aplite
and quartz-
porphyry, but not always the

and displacement is
rhyolite,
found along some. These systems
are:
Anaconda or
(1)
oldest,
east-west and carrying

important ore bodies. (2) Blue,
striking
striking in
earliest fault fissure,
general N. 55 W., and carrying

ores of great value;
(3) Mountain view breccia fault, striking
E. and carrying ore; (4)

northeaststriking
N. 75
Steward,
southwest,
bearing;
(5)
and not usually ore

Rarus fault, a com-
plex fissure of variable northeast
and
strike,
dipping about 45
with fragmental ore
in from
other veins
northwest,
dragged
200);
(Fig.
198,
faults,
non-orebearing;
tinental
(6)
striking
fault,
Middle
Con-
(7)
north-
south on eastern edge of district,

of recent age, with 1500 feet
vertical displacement,
on down-throw
and Butte
side (Fig. 198).
The
granite is
especially in the
of pyrite, sericite
much
altered by hydrothermal metamorphism,

Anaconda Hill area, so that it is now a mass
and quartz near the veins.
The ore deposits are fissure veins, formed by the filling of fissures
and replacement of the country rock, the oldest fissures having
been continuously mineralized.
ECONOMIC GEOLOGY
596
Within the Butte district there is: (1) A main or central

copper zone, free from zinc and manganese (2) An indeterminate
intermediate zone, with copper predominant, and with some
sphalerite, rhodochrosite and rhodonite; (3) An outer peripheral
zone, without copper, but filled chiefly with quartz, rhodonite,
rhodochrosite, sphalerite, and pyrite and which is silver bearing.
In the central or copper zone, the order of relative abundance
;
of the copper sulphides
is
tetrahedrite,
chalcopyrite,
(74);
chalcocite, enargite.,
tennantite
and
covellite.
bornite,
Quartz
and pyrite form the gangue.

Sales (74) gives the following details regarding the sulphides:
Chalcocite has supplied 60% of the Butte copper to date, occurring
Longitudinal vertical projection of the High Ore Vein, a member of

the Blue Vein system, showing distribution of the ore shoots.
(After Sales,
FIG. 199.
Amer.
Inst.
Min, Engrs., XLVI.)
and at
in veins of all ages,
Once regarded
down to below 3000 feet.

downward secondary enrichment
all levels
entirely as a
it is now divisible into, (a) sooty secondary chalcocite,

a
dull black coating on pyrite and other sulphides or
forming
product,
replacing
pyrite,
sphalerite,
enargite
and
chalcopyrite;
(6)
massive chalcocite, considered as primary because: (1) it is

abundant in the depest levels (over 3000 feet); (2) its intimate
association with bornite, enargite and pyrite show it to be conoccurs at all depths without relation to
found in dry veins, at deep levels, cut by the
older faults; (5) it replaces granite at deep levels; and (6) there
is no evidence of present replacement except in the sooty material.
Enargite is of wide vertical and lateral distribution, of com-
temporaneous;
topography;
(3)
it
(4) it is
paratively old mineralization, and usually primary but sometimes
secondary.
ECONOMIC GEOLOGY
598
Bornite
is
is
primary, of
all
ages,
and at
all levels.
unimportant and chiefly primary, so also
is
Chalcopyrite
covellite.
The vein outcrops are usually barren of copper, and while the
oxidation depth is variable, it averages 250 feet.
In the silver zone, quartz and manganese are the common
gangue materials, the veins showing on the surface as ledges
of
manganese-stained quartz.
FIG. 200.
fault
Plan of 500-ft. Level of Pennsylvania Mine, showing effect of Rarus

on different veins. (After Sales, Amer. Inst. Min. Engrs., XLVI.)
The Butte
ores have been derived primarily from igneous

the
rocks,
quartz porphyry having perhaps opened up the way
for the ore-bearing solutions, the elements carried by the latter
having included Si0 2

Au, Te, Bi, and K.
S, Fe,
Cu, Zn,
Mn,
As, Pb, Ca,
W,
Sb, Ag,
In the central part of the area, the more highly heated and acid
solutions deposited the copper ores, while the zinc, manganese
COPPER
599
and lead were precipitated toward the periphery where the temperature was lower, and the solutions more alkaline from reactions
with the granite.
In 1914 the smelting ores averaged 4.97 per cent copper, and
yielded about 28 per cent of the output, while the concentrating
FIG. 201.
Geologic
map
of western half of
ores averaged 2.04 per cent,

gold .059 ounce.
The
Butte
district.
(U. S. Geol. Surv.)
Silver averaged 1.83 ounces,
and
history of this mining camp is full of interest. Butte in 1864 was

difficulties in working the gravels directed attention to the
a gold camp, but
mineral-vein outcrops, and unsuccessful attempts were made to work their

copper and silver contents, so that it was not until 1875, following a period of
quiescence, that the discovery of rich silver ore in the Travona lode revived
the mining industry of Butte. In 1877 several silver mines were opened, followed by others; but this did not last many years, for with the drop in the
price of silver many mines closed, although one, the Bluebird, had produced
2,000,000 ounces of silver from 1885 to 1892.
ECONOMIC GEOLOGY
600
The copper mines were worked to only a limited extent at first, and the
industry did not assume permanance until 1879-1830, when matte smelting
was introduced. In 1881 the Anaconda mine, which was first worked for
silver, began to show rich bodies of copper ore, and since then the output
of copper has steadily increased, there being a
plants located at Anaconda and Great Falls.
Globe-Miami, Arizona District
(35,
36,
number
of
41).
large smelting
This
district
became well known through the Old Dominion mine at Globe,

long before the now more important ores at Miami were developed.
The formations include a pre-Cambrian crystalline complex,
the Final schist cut by granitic intrusives. Overlying these
unconformably is a thick series of Paleozoic sediments including
conglomerates, quartzites, shales and limestones. In Mesozoic
times probably there followed an intrusion of diabase and granitic
rocks, and then after an erosion interval Tertiary volcanics and
sediments, the Gila conglomerate being prominent
among the
Faulting of both pre- and post-Tertiary age is known.

Around Miami the great disseminations of chalcocite, in the
latter.
Final schist near the Schultze (Mesozoic) granite are of importance.

The original ore was a sulphide of iron and copper, which
in its upper part has undergone leaching and oxidation, accom-
panied by secondary enrichment of the ore below.
The
section
therefore shows a leached capping, followed by an irregular zone

of oxidized ore, and this in turn by a secondary enrichment zone,
showing grains and stringers of pyrite and chalcopyrite replaced

by chalcocite. The ore-bearing solutions are believed to have
come from the Schultze granite, and resulted not only in deposition of ore, but also a more or less complete silicification of the
schist.
These disseminated ores represent such an important type in the

few. figures showing their low grade, extent,
etc., as explanatory of their working at a profit, may be given.
The estimated ore reserves of the Miami Copper Company at
Miami l on January 1, 1915, were 19,500,000 tons of sulphide
West to-day that a
averaging 2.4 per cent copper, and 17,000,000 developed tons,

averaging 1.21 per cent copper, also 6,000,000 tons oxidized or
partly oxidized ore averaging 2 per cent copper. The copper
per cent in ore milled averaged 2.28 per cent. The mill extraction was 69.93 per cent, and the concentrates contained 39.31
per cent copper.
1
The
Inspiration
Company
near by has similar deposits.
COPPER
601
In the Globe section of the district the ore bodies occur as lenticular replacein limestone, and as fault lodes, or fissure zones in diabase.
Much of the limestone ore thus far extracted has been oxidized, but that
ments
Some bodies of primary ore of commercial

value have also been developed. In 1914 the average copper contents of the
smelting ore was 8.28 per cent; concentrating ore 4.69 per cent; and silica
The gold and silver run low, but are saved.
lining, 3.12 per cent.
in the diabase is enriched material.
Mineral Creek
here
is
or
Ray
similar to that at
FIG. 202.
Creek
district,
Miami.
The
Ariz.
(42).
The geology
deposits (Figs. 202 and 203)
Vertical section (A B, Fig. 203) showing ore body in schist, Mineral

district, Arizona.
(After Tolman, Min. and Sci. Press, XCIV.)
are found in sedimentary rocks associated with faults and fissures,

or as disseminations in the Final schist and granite, this second
type being the more important.
In 1914 the ore
concentrated
averaged
1.76 per cent copper. At

the beginning of 1915
the
ore
were
reserves
estimated at 74,765,789
averaging 2.214
tons,
per cent copper.
Another
interesting
of
the dissemi-
district
nated type is that of the

Burro Mountains in New
Mexico
(86).
Virailina
region
This ^ IG> ^3.
Va
.
is
of
interest
Geologic map of a portion of the

Mineral Creek, Ariz., copper district. (After
TolmaTli
XCIX
.)
especially because of the

relationships of the primary sulphides
found within the ore
body.
The rocks are greenstone and sericitic schists, intruded in places

by granite and gabbro. The schists have been derived from a
ECONOMIC GEOLOGY
602
and quartz porphyries with a preponderating

fissure veins, which occur in the chloritized
and epidotized andesite, contain primary bornite and chalcocite,
in a gangue of quartz, and subordinate calcite or epidote.
The
ore-bearing solutions are thought to have come from the granite,
series of andesites
amount
of tuffs.
The
Quartz vein carrying copper sulphides, between walls of chloritized and

schistose andesite, Virgilina, Va.
(H. Ries, photo.)
FIG. 204.
whose intrusion postdates the development
of schistosity in the
volcanics.
is
Alaska.
Copper River District
situated
some distance from the
access,
has been but
facilities
little
(23, 24)
coast,
This
region,
and hence
which
difficult of
developed, although transportation
have now been provided.
The primary
ore is chiefly chalcocite with some bornite reTriassic

limestone near a greenstone. The ore is chiefly
placing
chalcocite, but other sulphides as well as oxidized ores occur.
In the Bonanza mine on the Chitina River, the ore consists

mass of chalcocite in limestone, averaging about 60 per
of a solid
cent copper, with about 22 ounces of silver to the ton.
COPPER
603
Foreign Deposits.
Among those which deserve mention here is the tlammelsberg deposit of the northern Hartz district of Germany, interesting not
only historically, but also because of its disputed origin. The ore body lies
more or less conformably in strongly folded Devonian slates, and has a variable thickness.
The
sphalerite in a
gangue
ore minerals are chalcopyrite, pyrite, arsenopyrite and

chiefly of barite.
Banding is present, and the ore
minerals excepting pyrite are drawn out into streaks. Bergeat 1 and Klockmann 2 thought it a sedimentary deposit, while Vogt 3 and others believed
to have been deposited from solutions of
magmatic origin. Lindgren and

a bedded vein, in part conformable to the surrounding slates,
and exhibiting the structure of a dynamo-metamorphic rock. They agreed
with Vogt as to the source.
it
Irving
called
it
At the Braden mines in the Chilean Andes, the ore minerals
are chalcopyrite,
bornite, magnetite and sphalerite, with toumaline, quartz, sericite,

etc., occurring as lodes in andesite, at its contact with a tuff.
epidote,
vol-
The
canics surround an ancient crater.
Chuquicamata, Bolivia, remarkable for its great masses

by sulphides should also be mentioned. 3
of brochantite un-
derlain
Native Copper Deposits.
Deposits of native copper occur-
ring in basic volcanic rocks, especially those of basaltic character,
form a widespread type.
work
from
They
are not strictly speaking the
of circulating waters, although the minerals are precipitated

solution.
noteworthy fact is the constant association of
the copper with zeolites, calcite, quartz, epidote, etc., the ore and
gangue minerals either filling the gas cavities or replacing the rock.
The igneous rocks are regarded by many as the source of the
copper, analysis often showing a small percentage of this metal,
and its concentration seems to be associated with the development of the zeolites, so that a theory proving the origin of one
must include the other. It is therefore believed by some that
the magmas erupted either on the ocean floor, or in bodies of
fresh water, absorbed the water of these on cooling, and that this
on mixing with magmatic exhalations broke up the copper silicate
Iron silicates were
present, changing it to copper chloride.
These chlorides were then decomposed by
similarly affected.
silicates or even carbonates of lime, yielding native copper, ferric
oxide and calcium chloride as shown by the following reactions:
2FeCl2+2CuCl+3CaSi03=2Cu+Fe 2 03+3SiO2+3CaCl2.
Widespread as native copper deposits of this type are, they are
In North America, the Michigan
all of economic importance.
not
Erzlagerstatten, p. 329, 1904.
Berg und Huttenwesen des Oberharzes, 1895,
Zeitschr. prak. Geol., 1894:
"Econ. Geol., VI: 303, 1911.
p. 57.
173.
5
Min. Mag., IX:
36, 1913.
ECONOMIC GEOLOGY
tf)
IS
COPPER
605
all others.
Some production has also been obtained
from the Triassic traps of New Jersey (82) and from those on the
Bay of Fundy, in Nova Scotia (I15a). Other occurrences are
known in Oregon (92a), the White River region of Alaska (22),
and in Arctic Canada (114). In other countries they are known
ones outrank
MAP
Of
THE
PORTAOE LAKE
MINING
FIG. 207.
Map
DISTRICT
of a portion of the
Michigan copper
district,
showing strike cf
lodes.
in
New
etc.,
Guinea, Brazil, the Transbaikal,

but are not all productive.
Norway,
i
Beck, Lehre v. d. Erzlagerstatten, I: 345, 1909.
ZHussak, Centrbl. f. Min., 1906: 333.
Beck, Zeitschr. prak. Geol., 1901: 391.
*Ibid. VII:
t
12, 1899.
Germany,
606
ECONOMIC GEOLOGY
This region, which was discovered in 1830

Michigan (63-68).
has
become one of the most famous, as well
by Douglas Houghton,
as one of the leading, copper-producing districts of the world.
The rocks of the region, known as the Keweenaw series, consist

of interbedded lava flows, sandstones, and conglomerates, the
latter being rounded fragments of igneous rocks, mainly reddishquartz porphyry.
This series of beds, whose entire thickness
may
be from 25,000
to 30,000 feet, dips westward (Fig. 206) from 35 to 70 degrees,

being overlain conformably on the west by sediments, while on
(Sl Copper jgSgAmygdaloid EEEB Tra P
/J4YGDALOID COPPER LODE

FIG. 208.
IN
QUINCY WINE
Section showing occurrence of amygdaloidal copper, Quincy Mine,

Mich. (After Richard, Eng. and Min. Jour., LXXVII.)
the east they are faulted up against the horizontal
Potsdam sand-
stones.
These beds form a belt 2 to 6 miles wide, which extends from

of the Keweenaw peninsula, and rises as a
ridge from 400 to 800 feet above the lake (PL LVI).
The ore, which is native copper, and is occasionally associated
with native silver, occurs (1) as a cement in the conglomerate of
Houghton to the end
porphyry pebbles, or replacing the latter, (2) as a filling in the

amygdules of the lava beds (Fig. 208), (3) as masses of irregular
and often large size, in veins with calcite and zeolitic gangue.
The tilting of the beds has been accompanied by some slipping
and cross faulting, and the presence of copper in cross joints and
planes indicates later deposition.
veins, which cut both the igneous and sedimentary rocks,
have yielded much copper in former years, and the large masses
slip
The
obtained from them have
made the region famous but at the pres;
ECONOMIC GEOLOGY
608
ent time most of the production comes from the Calumet conglomerate, while the balance comes from two other copper-bearing
conglomerates known as the Albany and the Allouez, and from the
ashbeds and amygdaloids, whose gas cavities are filled with a mixture of native copper, calcite, and zeolites.
A curious and hitherto unexplained feature
is the irregular distribution of the copper in the different beds, which may be due to the
copper solutions being directed by certain joints or slip planes.

Thus the Calumet conglomerate carries practically no ore outside
of the Calumet and Hecla ore shoot, which is three miles long, 12-15
feet thick, and has been mined to a depth of 5000 feet.
Various theories have been brought forward to account for the

origin of the copper ores in this region.
The diabase was looked upon by Pumpelly as a possible source

and since its extensive alteration was no doubt accompanied by the oxidation of protoxides of iron, this might account
of the ore,
for the reduction of the copper mineral to the native or metallic
condition, it being
metallic copper (1).
known
More
that ferrous salts

recently
Lane
may
(65, 66)
precipitate
has suggested
that originally buried water has also been an important factor

in concentration, but agrees that the final precipitation was by
water working downward.

Lane has pointed out that the mine waters show a striking
increase in chlorine with depth, in fact there is more than enough
to satisfy the sodium present, and it is contained in relatively
Moreover, the molecules
large amounts of calcium chloride.
of sodium chloride decrease steadily with depth, while those of
calcium chloride increase.
He
therefore suggests, and his views are backed by chemical

experiments, that the basalt flows originally contained small percentages of copper that while still heated they no doubt absorbed
;
sea water charged with sodium chloride, and in later times atmospheric waters not containing any, but obtaining it as they seeped
through the rocks.

These waters, rich in NaCl, migrated downward, taking copper in
solution as copper chloride.
Reactions with the glassy base or original minerals of the volcanic
rocks gave rise to the formation of sodium silicates, accompanied
by
precipitation of
copper and formation of calcium chloride.
Descending solutions from wide areas became concentrated along

lines favorable to underground circulations, and hence shoots of
COPPER
relative richness resulted.
slips
It
is
609
supposed that certain faults and
guided these waters.
although reasonable and backed by laboratory

may not be universally accepted, and some observers believe that these deep-seated waters with their peculiar
The
theory,
experiments
(5),
composition are very likely of magmatic origin.

Although these deposits were worked in prehistoric times, as evidenced
by copper implements and ornaments found in the mines, the famous Calumet
and Hecla Mine was not opened up until 1846. In 1847 Michigan produced
213 long tons of the total United States production of 300 tons of copper.
Since 1863 the annual output has exceeded 1000 tons and gradually and
Since
steadily increased up to 1905, when it reached 230,287,992 pounds.
that year it has only exceeded it once, and has usually been less.
The ores from this district, which are known as Lake ores, 1 are all of low
grade, but the deposits are of great extent and rather uniform mineralization, and this fact, together with the possibility of high concentration and low
cost of refining, makes it possible to work these low-grade deposits at a profit.
The richest ore now mined contains under 1.5 per cent of copper, while
the poorest runs but little over .5 per cent.
The crushed and concentrated material carries about 65 per cent copper,
and this passes through a combined smelting and refining process.

That portion of the copper which contains enough silver to make its
recovery profitable, and some which runs too high in impurities for certain
The amount so treated has been lessened,
uses, is refined electrolytically.
owing to a recent demand
for copper carrying arsenic.

covery of silver per ton of rock mined was .2 fine ounce.
B. Deposits from Meteoric Waters

In
many parts
The average
re-
of the world there are low-grade disseminated ores of copper
(chiefly chalcocite) in sandstones
and
shales, ranging
from Carboniferous to
are not as a rule sufficiently rich to work, although the

carbonates on the surface may make them attractive propositions to some.
That they seem to have been concentrated from the surrounding rock by
Triassic in age.
They
is a commonly accepted view.

This type of copper occurrence is widespread in the Red Beds (Permian)
of the southwest, but is of no economic importance.
Similar deposits have
been worked in the well -known Corocoro 2 district of Bolivia, and in the
Triassic of England.
They are also known in the Permian of Russia and
Bohemia, and the Triassic of western Prussia.
Reference may be m/ide in this connection to the famous Mansfeld copper
meteoric waters
deposits of Germany, which are probably of syngenetic nature.

occur as minutely disseminated sulphides in Permian shale. 3
These
1
The term has now lost its original meaning, since copper from western states
brought to Michigan for refining and sold as Lake ore.
Vogt, Krusch u. Beyschlag, Lagerstatten, II: 428, 1912.

Bergeat, Erzlagerstatten.
is
ECONOMIC GEOLOGY
610
Deposits, Usually Lens-Shaped, in Crystalline Schists.
number of copper sulphide

in character, and occurring
or
less
lenticular
often
more
deposits,
in schistose rocks, which may be either igneous or sedimentary
Scattered over the world are a
Some
metamorphics.
criticism
may
be urged against grouping
them together, because their mode of origin is admittedly somewhat variable, but otherwise they show more or less mineralogical
and structural resemblances.
In general
it
may
be said that they represent deposits formed
at deep or intermediate levels, by replacement or in cavities.

Zones of shearing have often afforded channel ways for the
While the host rock is often a schist, in other cases it

of which little or nothing now remains,
so complete has been the replacement.
United States.
Copper deposits in schist are most prominent
The more
in the Appalachian belt of the. east, and in California.
solutions.
may have been a limestone,
important ones are reviewed below.
Appalachian States
contain a
number
Maine to Alabama,
(29,
30,
104).
The Appalachian
states
of copper deposits in schist distributed from

but few of them are of commercial importance.
Here we have steeply dipping

and faulted schists.
These lenses, whose exact origin was not clear until sufficient
mining had been done to furnish the necessary evidence, range
from a few feet to over 250 feet in thickness, have the shapes
and character of closely folded sedimentary beds. The ores are
somewhat metamorphosed and the gangue minerals bent. PriDucktown,
Tenn.
(97-99).
lenses replacing calcareous beds in folded
ore consists of pyrrhotite, pyrite, chalcopyrite, sphalerite,

bornite, hematite and magnetite in a gangue of calcite, actinolite,
mary
tremolite,
zoisite
and other
deep-seated
conditions
garnet,
representing
silicates,
and
combination
limestone
replace-
ment. The gossan of the different bodies, now worked out, had
a maximum thickness of 100 feet, and showed 40-50 per cent Fe,
under 12 per cent SiC-2 and AbOs, and .3-. 7 per cent Cu. Between the gossan and dense sulphides there were found shallow
zones of rich chalcocite.
In 1914 the ores yielded 28.7 pounds of blister copper per ton,
or 1.435 per cent, with an average value of 9 cents in gold and
Some of the copper is marketed without
silver per ton of ore.
The massive ore requiring little timber in
electrolytic refining.
COPPER
611
mining, together with cheap fuel and labor costs, have
made
it
work these low-grade ores at a profit. Pyritic smelting

employed, and large sulphuric acid plants have been erected
possible to
is
to utilize the sulphur driven oft from the ores in roasting.

EAST TENNESSEE^C/
CULCHOTE
OLD TENNESSEE
^CALLAWAY
Grajircke and
icica schist
POLK COUNTY
Stiurolitic beds
2000
Plan of ore bodies at Ducktown, Tenn.

Geol. Swr., Bull. 470.)
FIG. 209.
4000 Fc-t
(After
W. H. Smmons, U.
5.
The Gossan Lead of southwestern

and the copper deposits of Ore Knob,
North Carolina, also belong to this type. At the former the ore
is a mixture of pyrrhotite with subordinate chalcopyrite, and
admixed quartz and schists. The vein fills a fault fracture between sericite schists, which contains mica, calcite, quartz, and
actinolite, replaced by the later pyrrhotite and chalcopyrite (Fig.
The copper content is low, viz., .75 per cent, and hence
211).
Virginia-North Carolina.
Virginia (104) (Fig. 210)
the ore
is
used for acid making, but the residue
is
available for
copper.
The ores occur in a pre-CamArizona, Jerome District (31).

brian schist, and consist of pyrite, chalcopyrite, some sphalerite,
and varying amounts of quartz, replacing the schist.
ECONOMIC GEOLOGY
Map of Carroll County, Va., pyrrhotite area, showing position of the

Great Gossan Lead " in heavy black band, and principal copper mines located
on it. Broken lines are other probable leads. (After Watson and Weed, Min.
FIG. 210.
"
Res, Va.)
FIG. 211.
Section of ore from Chestnut Yard, Va., showing pyrrhotite (white)
and chalcopyrite (black) replacements

Weed and Watson, Econ. Geol., I.)
in hornblende (parallel lines).
(After
The ore body is really composed of a series of irregular lenses.

Unlike most of the other Arizona copper deposits, this ore carries
rather high gold and silver values.
In the Klamath Mountains of Shasta
California (44, 45, 46).
County, there are important replacement deposits of pyritic ore
occurring mainly along fissures and shear zones of an intrusive
COPPER
Mesozoic alaskite porphyry. Two
Sacramento River are recognized.
613
areas
separated
by the
An
eastern one, containing the Bully Hill and Afterthought

districts, with deposits more vein-like, the ore siliceous, relatively
high in chalcopyrite, and sphalerite important. A western one,

with more or less flat, tabular ore bodies, carrying pyrite, some
chalcopyrite and variable sphalerite, the last being sometimes
enough to form zinc ore.

is gypsum, calcite and barite, and while chalcocite and bornite are sometimes found intergrown with chal-
rich
The gangue
copyrite, they
may
at times be secondary.
Good gossans
are
found.
Magmatic waters
are supposed to have deposited the ore in the
highly sericitized alaskite porphyry.

In 1914 the average copper content was 3.56 per cent, with
$1.70 per ton of precious metals.
The
so-called Foot Hills belt (46), occupying a somewhat extenCounty, carries pyrite and chalcopyrite
sive area in Calaveras
lenses in schistose rocks.
The
ores at times carry considerable
and precious metals.

Alaska. Prince William Sound
lead, zinc
the ore
The
District (21).
In this district
chalcopyrite disseminated through metamorphic schists.

most important mine is on Latouche Island, and here the ore,
is
which is a mixture of chalcopyrite, pyrrhotite, and pyrite, has

been deposited mainly as a cavity filling, less often as a replace-
ment
or impregnation, in a shear zone in interbedded slates
and
graywackes.
Canada (112).
number of interesting pyritic deposits occur
in the eastern townships of Quebec.
There are three belts of
by apparently Paleozoic sediments

of the former prove to be altered
but
some
by intrusives,
crystalline rocks separated
cut
schistose volcanics.
Most
of the copper deposits are associated with more or less

altered
schistose volcanic rocks, and while a few were
highly
formed by the impregnation and partial replacement of limestone,

most of them have originated by the irregular impregnation of
the more schistose bands along shear zones in metamorphosed
igneous rocks.
given
In other cases the replacement of the schists has

bodies of ore, which include some of the
rise to lenticular
most important mines. The sulphides are chiefly chalcopyrite

and pyrifce, but zinc and lead may occur in small amounts.
ECONOMIC GEOLOGY
614
Of the many foreign occurrences, the two best
known perhaps are those of Rio Tinto, Spain, and Mount Lyell, Tasmania.
The former occur as lenses, often of large size, in sheared and schistose
porphyries and slates. The massive pyritic ore carries pyrite, chalcopyrite,
The hematite gossan, caps sulphides which, due to
sphalerite and galena.
enrichment, carry from 3 to 12 per cent copper. The wall rocks, according to
Finlayson, show hydrothermal alteration. Klockman argued for a sedil
DeLaunay regarded them as veins or lodes formed by
mentary origin
;
Vogt assigned a pneumatolytic origin, following the por3

phyry intrusion; while Finlayson believes them to have been the result of
metasomatism by magmatic solutions along shear zones. 4
At Mount Lyell we have great lenses of pyrite, with quartz and barite
gangue, occurring chiefly in sericite schists, which have been intruded by
The ore carries from 2 to 3 per cent copper, due to a chalcoporphyrites.
5
Large deposits are also worked in Russia.
pyrite content.
cavity
filling;
Since prehistoric times copper alloyed with

Uses of Copper.
tin has been used in various parts of the world for the manufacture
Thus it was used for this purpose in Homeric times,
of bronze.
it is found in the lake dwellings of Switzerland.
The bronze
found in Troy contains a very little tin, and since this metal is not
found in the excavations in the West, it seems probable that the
bronze was made in Asia, perhaps in China or India, by some
secret process, and imported to the western countries.
By an alloy of copper and tin, although both metals are soft, a
comparatively hard metal is produced. The properties of this
and
vary greatly according to the proportions of the

constituents, and these vary with the use for which the
is
United States ordnance is 90 per cent copper
intended.
alloy
and 10 per cent tin, while ordinary bell metal is about 80 per cent
copper, though the percentage varies with the tone required.
Statuary bronze is generally an alloy of copper, tin, and zinc;
and, in these various bronzes, the color varies from copper-red
to tin-white, passing through an orange-yellow.
An alloy of copper and zinc produces brass, which is found of so
much value for small articles used in building and for ornamental
alloy, bronze,
two metallic
purposes in machinery.
Copper
also
is
used in roofing and
plumbing.
large supply of this metal is made into copper wire, and the
of copper is in electricity, for which its
most important present use

1
Zcitschr. prak. Geol., 1897:
Ann. des Mines.,
113.
XVI:
Zeitschr. prak.
Geol., 1894:
241.
Econ. Geol., V: 357, 1910.

Stickney, Kyshtim deposits, Min. Mag., XIV: 77, 1916; also Econ. Geol.,
XI, 1915.
ser. 7,
407.
COPPER
high conductivity especially
fits it
615
for the transmission of electric
currents.
Production of Copper.
The production of copper in the United
States has increased steadily and rapidly in the last fifty years,
placing the United States in the lead of the world's copper producers.
This increase can be seen from the following tables
PRODUCTION OF COPPER IN THE UNITED STATES, 1910-1914, BY STATES,

IN
POUNDS
ECONOMIC GEOLOGY
GIG
COPPER PRODUCED IN 1914 FROM ORES IN WHICH COPPER CONSTITUTES

THE PRINCIPAL VALUE, BY STATES
State
COPPER
617
TOTAL UNITED STATES IMPORTS AND EXPORTS OF COPPER, INCLUDING ORE,

MATTE, AND REGULUS, Pias 3 BARS, INGOTS, PLATES, RODS AND WIRE
YEAR
ECONOMIC GEOLOGY
618
and Murdoch, Amer. Inst. Min. Engrs., Trans., XLV: 26, 1913. (Secondary sulphides.) 5. Fernekes, Econ. Geol., II: 580, 1907. (Copper
6. Kemp, Econ. Geol.
precip'n from chloride sol'ns by ferric chloride.)
I:
7. Lane, Can. Min. Inst,, XIV: 316,
11, 1906.
(Sec'y enrich't.)
1912.
(Native copper deposits.) 8. Lindgren, Econ. Geol. VI: 687,
1911.
(Copper ores in basic rocks.) 9. Lindgren, Econ. Geol. VI:
568, 1911.
(Copper in sandstones and shales.) 10. Lindgren, U. S.
Geol. Surv., Bull. 394: 131, 1909.
(Copper ore reserves.) 11. Posnjak, Allen and Merwin, Econ. Geol., X: 491, 1915.
(Sulphides of
12. Rogers, Min. and
Sci. Pr., CIX:
copper.)
680, 1914.
(Sec'y
13. Thompson, Econ. Geol., IX: 171, 1914.
(Rel'n pyrand chalcopyrite to other sulphides.) 14. Spencer, Econ. Geol.,
15. Stevens, Copper Hand621, 1913.
(Chalcocite enrich't.)
Published annually by W. H. Weed, New York. 16. Stokes,
enrich't.)
rhotite
VIII:
book.
Econ. Geol., I: 644, 1906. (Sol'n transport'n, dep'n of copper.) 17.

Tolman, Amer. Inst, Min. Engrs., Bull., Feb., 1916: 401. (Types of
18. Tolman and Clark, Econ. Geol., IX: 559, 1914.
Chalcocite, etc.)
(Chemistry of copper sulphide dep'n.) 19. Tolman and Clark, Min.
and
Sci.
Pr.,
CVIII:
172,
Copper Mines of the World,
AREAL PAPERS.
1914.
(Sulphide
enrich't.)
20.
Weed,
New York.
Alaska:
21. Johnson, U. S. Geol. Surv., Bull. 592: 237,

Sound.) 22. Knopf, Econ. Geol., V: 247, 1910.
(Native copper, White River.) 23. Lincoln, Econ. Geol., IV: 201, 1909.
24. Moffit and Madden, U. S. Geol. Surv., Bull.
(Big Bonanza Mine.)
25. Smith, P. S., U. S. Geol. Surv.,
374, 1909.
(Kotsina-Chitina.)
Bull. 592: 75, 1914.
26. Wright, C. W., U. S. Geol.
(Ketchikan.)
Surv., Prof. Pap. 87, 1915.
(Copper Mtn.) 27. Wright, C. W., Econ.
1914.
(Pr.
Geol., Ill:
Wm.
(Kasaan Peninsula.) 28. Wright, F. E., and

410, 1908.
(Ketchikan.)
Appa-
Wright, C. W., U.
lachian States:
29. Emmons, U. S. Geol. Surv., Bull. 432, 1910.

(Me.
and N. H.) 30. Weed, U. S. Geol. Surv., Bull. 455, 1911; Amer.
Arizona: 31. Graton,
Inst, Min. Engrs. Trans., XXX: 454, 1901.
U.S. Geol. Surv., Min. Res. 1907, Pt. I: 597, 1908. (United Verde.)
32. Jenney, Eng. and Min. Jour., XCVII: 467, 1914.
(Porphyry ores,
Bisbee.)
33. Lindgren,
U.
Pap. 43, 1905.
(Clif-.
Ransome, U. S. Geol. Surv., Prof. Pap. 21, 1904.

35. Ransome, Ibid., Prof. Pap. 12, 1903; also Min. and Sci.
(Bisbee.)
36. Ransome, U. S.
Pr., C: 256, 1910 andCII: 747,1911.
(Globe.)
Geol. Surv., Bull. 529: 183, 1913.
37. Ransome,
(Globe.)
Ibid.,
Bull. 529;
38. Ransome, Ibid., Bull. 529 :192,
179, 1913.
(Bisbee.)
1913.
(United Verde.) 39. Ransome, Ibid., Bull. 540: 139, 1914.
40. Stewart,
Amer. Inst. Min. Engrs., XLIII: 240,
(Superior.)
1913.
41. Tovote, Min. and Sci. Pr., CVIII: 442 and
(Silver Bell.)
(Globe district.) 42. Weed, Min. Wld., XXXIV: 153,
487, 1914.
1911.
Calif.
State Min. Bur.,
California: 43. Aubury,
(Ray.)
Bull. 23, 1902.
44. Boyle, Amer. Inst, Min. Engrs., Trans.,
(General.)
ton-Morenci.)
34.
XLVIII:
67, 1915.
430:
1910.
71,
Bull. IV:
411.
(Bully Hill.) "45. Graton, U. S. Geol. Surv., Bull.

46. Knopf, Calif. Univ. Dept. Geol.,
(Shasta Co.)
47. Reid, Econ. Geol., II: 380, 1907.
(Foothills belt.)
COPPER
619
48. Turner and Rogers, Econ. Geol., IX: 359, 1914.

(Plumas Co.) 49. Bagg, Econ. Geol., Ill: 739, 1908. (Sangre de
Colorado: 50. Bastin and Hill, Econ. Geol., VI: 465,
Christo Range.)
51. Emmons, S. F., U. S. Geol. Surv., Bull. 260,
1911.
(Gilpin Co.)
1905.
(Copper in Red Beds.) 52. Emmons, W. H., U. S. Geol. Surv.
Bull. 285, 1906.
(Cashin Mine, Montrose Co.) 53. Lindgren, U. S.
(Copperopolis.)

(Chaffee, Fremont and Jefferson Cos.) 54.
163, 1903.
(Pearl, Colo.)
Spencer, U. S. Geol. Surv., Bull. 213:
(Seminole
Georgia: 55. Watson, U. S. Geol. Surv., Bull. 225, 1904.
copper deposits.) Idaho: 56. Calkins and Jones, U. S. Geol. Surv.,
Bull. 540: 167, 1914.
285, 1906.
430, 1910.
(St.
57. Collier,
(Mullan.)
Joe River basin.)
58. Gale,
U.
U.
Geol. Surv., Bull.
S.
(Montpelier, Bear Lake Co.) 59. Kemp, Amer. Inst. Min.

(White Knob.) 60. Lindgren,
Engrs., Trans., XXXVIII: 269, 1908.
Min. and Sci. Pr., LXXVIII: 125, 1899. (Seven Devils.) 61. Ransome
and Calkins, U. S. Geol. Surv., Prof. Pap. 62:

d'Alene.)
Maryland: 62. Butler and McCaskey,
150,
1908.
Amer.
Inst.
(Coeur
Min.
XLIX:
284, 1915.
(New London Mine.) Overbeck, Econ.
XI:
1916.
63.
Geol.,
151,
(Metallographic study.)
Michigan:
1910.
(Keweenawan copper.) 64.
Grout, Econ. Geol., V: 471,
65. Lane, Mich.
Irving, R. D., U. S. Geol. Surv., Mon. V. 1885.
Engrs.,
66. Lane, Can. Min.

Geol. ser. 4, Vols. I and II, 1911
Bull. 7, 1909.
67. Rickard,
(Copper mine waters.)
Geol. Surv.,
Inst. Quart.,
Eng. and Min.
LXXVIII:
Jour.,
585,
625,
665,
745,
785,
865,
68. Van Hise and Leith,

(Historic and geologic.)
905, 1025, 1904.
U. S. Geol. Surv., Mon. LII: 573, 1911. Missouri: 69. Bain and
Montana:
(General.)
267, 1905.
Ulrich, U. S. Geol. Surv., Bull.
Amer. Inst. Min. Engrs., XLVI, 1914. (Butte minerals.)

Econ. Geol., VII: 35, 1912.
(Alter'n wall rock, Butte.)
72. Ray, Econ. Geol., IX: 463, 1914.
(Paragenesis Butte minerals.)
Ref. 117, Chap. XIV. (Up73. Rogers, Econ. Geol., VIII: 781, 1913.
70. Bard,
71. Kirk.
ward sulphide
XLVI,
1914.
enrich., Butte.)
(Gen'l on Butte.)
74.
Sales,
75. Sales,
Amer. Inst. Min. Engrs.

Econ. Geol., V: 15, 1910.
76. Weed, U. S. Geol. Surv., Prof. Pap.

(Superficial alter'n, Butte.)
77. Winchell, Eng. and Min. Jour.,
1912.
(Butte.)
Nevada: 78. Carpenter, Min. and
782, 1903.
(Chalcocite synthesis.)
LXXXV:
74.
Sci.
Pr.,
CI:
Geol., Bull. 4:
380: 99, 1909.
(Ely.)
1908.
1910.
4,
284.
79. Lawson, Cal. Univ. Dept.

Ransome, U. S. Geol. Surv., Bull.
(Yerington.)
(Ely.)
(Yerington.)
80.
81. Spencer, Ibid., Bull. 529:
189, 1913.
New Jersey: 82. Lewis, N. J. Geol. Surv., Ann. Rept., 1907: 131,
New Mexico: 83. Ball, Min. and Sci. Pr., July 26, 1913. (Sand-
stone deposits, Bent.) 84. Lindgren, Graton and Gordon, U. S. Geol.

(Santa Rita.) 85. Paige, Econ,
Surv., Prof. Pap. 68: 305, 1910.
86. Somers, Amer,
(Santa Rita, Chino.)
Geol., VII:
547, 1912.
Inst.
U.
S.
Min. Engrs.,
Bull.
101:
Geol. Surv., Bull. 470,
(Burro Mts.) 87. Paige,

958, 1915.
1911.
(Burro Mts.) North Carolina:
399, 1911.
(Virgilina.)
Geol., VI:
(Gold Hill district.)
Surv., Bull. 21, 1910.
Bull. 22, 1910.
(Cid district.) 91. Weed, Amer.
88. Laney,
Econ.
N. Ca. Geol.
89. Laney.
90. Pogue'
IUd.,
Inst.
Min
ECONOMIC GEOLOGY
620
Engrs.,
Trans.,
W.
Tarr,
XXX:
Oklahoma:
449.
A., Econ. Geol.,
(Types of deposits.)
V: 221, 1910.
(Copper in
Red
Lindgren, U.S. Geol. Surv., 22Ann. Rept.,Pt.2: 551, 1901.
Eng. and Min. Jour.,
XXXV;.
Beds.)
92.
92a.
Pennsylvania:
1883.
(Adams Co.)
(South Mountain.)
Kept., July, 1914.
95. Lyman, Jour. Frank. Inst., CXLVI: 416, 1898.
(Bucks and Montgomery counties.) 96. Stose, U. S. Geol. Surv., Bull. 430, 1910. (So.
93. Bailey,
94. Bevier,
Top and
Geol.
88,
Com.
Emmons and Laney, U. S. Geol. Surv., Bull.

(Ducktown.) 98. Kemp, Amer. Inst. Min. Engrs.,
(Ducktown.) 99. Weed, U. S. Geol. Surv.,
Trans., XXX] _224, 1901.
Bull. 455: 152, 'l911. Texas: 100. Phillips, Eng. and Min. Jour., XCII:
Utah: 101. Beeson, Amer. Inst. Min.
1181, 1911. (Permian ores.)
Engrs., Bull. 107: 2191, 1915.
(Bingham.) 102. Boutwell, U. S. Geol.
103. Butler, U. S. Geol. Surv.,
Surv., Prof. Pap. 38: 1905. (Bingham.)
Prof. Pap. 80, 1913 ;" also Econ. Geol. IX: 413 and 529, 1914.
(San
Francisco district.) Virginia: 104. Watson, Min. Res. Va., 1907.
(Va.)
105. Weed and Watson, Econ. Geol., I: 309, 1906. (Va.) 106. Watson,
Geol. Soc. Amer., Bull. XIII: 353, 1902.
107. Laney, Econ. Geol.,
VI: 399, 1911.
Washington: 108. Weaver, Wash. Geol.
(Virgilina.)
T
Wisconsin: 109. Grant,
is.
Geol.
Surv., Bull. 7, 1912.
(Index.)
and Nat. Hist. Surv., Bull. 9, 1903. (Douglas Co.) Wyoming: 110,
111. Spencer.
Ball, U. S. Geol. Surv., Bull. 315, 1907.
(Hartville.)
Ibid., Prof. Pap. 25, 1904.
(Encampment district.) Canada: 112,
Bancroft, Dept. Col'n, Mines and Fisheries, Mines Branch, Que., 1913.
113. Clapp and Cooke, Can. Geol. Surv., Summ. Rep., 1913:
(Quebec.)
84, 1914.
(Vancouver Is.) 114. Douglas, Can. Min. Inst., XVI: 83,
1914.
115. Drysdale, Can. Geol. Surv.,
(Native copper, Arctic.)
Mem. 77, 1916. (Rossland.) 115a. Ells, Can. Geol. Surv., Min.
116. Le Roy, Can. Geol. Surv., Mem.
Res., 1904.
(N. S., N. B., Que.)
Mtn.)
Tennessee: 97.
470;\ 151,
1911.
21,
117. Le Roy, Ibid., Mem. 19, 1913.

(Phoenix.)
(Mother
118. McConnell, Can. Geol. Surv., Mem. 58, 1914.
(Texada
119. Cairnes, Internat. Geol. Congr., Can., 1913, Guidebook of
1912.
Lode.)
Is.)
Excursions, No. 10.
CV,
107, 1912.
(White Horse.)
(South
120. Stewart,
Rossland.)
See also Annual Reports, Minister of Mines,
especially Rept. for 1914: 143 for Granby Bay.
Min. and
Sci.
Pr.,
belt,
British
Columbia,
LEAD AND ZINC

IT is usually customary to treat these two ores together for the
reason that they are so frequently associated with each other, but it
must not be understood from this that they are found free from
association with other metals, as in the Rocky Mountain region for
example, gold, silver, or copper may often occur with them, forming
ores of
The
somewhat complex character.

form a somewhat
silver-lead ores
distinct class
and are treated
separately.
Ore Minerals
of Zinc.
percentage of zinc
The
zinc-ore minerals, together with ths
which they contain, are:
Sphalerite (Isometric)
Wurtzite (Hexagonal)
Smithsonite
Calamine
....
ECONOMIC GEOLOGY
622
Ore Minerals
of
their composition
are:
Galena
Lead.
The
lead-ore minerals, together with

of lead which they contain,
and the percentage
LEAD AND ZINC
623
masses or disseminations, formed by replacement or impregnation in limestones or quartzites; (4) in contact-metamorphic

deposits; (5) in cavities not of the fissure-vein type; and (6) in
residual clays.
Mode of Origin. While both lead and zinc may form under
a variety of conditions, they are not found in commercial quantities
in igneous rocks including pegmatites.
Occurrences of workable
character
of
one
or
the
other
found
are
in:
(1)
contact
metamorphic deposits; (2) deeper zone veins; (3) intermediate

depth veins; and (4) in sedimentary rocks, unassociated genetically with igneous ones, and concentrated by meteoric circulation.
The third and fourth are the most important, and veins of the
third often contain gold, silver, and copper, but these are treated
in the next two chapters.
Neither lead nor zinc ores are restricted to any one formation,
but the majority of economically valuable deposits of these metals,
without silver, gold, or copper, are found in the Paleozoic formations,
although a few are
known
in
pre-Cambrian and Triassic
(Silesia) rocks.
While the metallic content of the ore as mined is often low, still,
owing to the great difference in gravity between ore and gangue
minerals (excepting pyrite or marcasite and blende), it is often
possible to separate them by mechanical concentration; and for
the zinc ores magnetic separation has been successfully tried.
Galena is
Superficial Alteration of Lead and Zinc Ores.
often altered near the surface to anglesite or cerussite.
The
is unstable in the presence of carbonated waters
former, however,
and changes readily to the carbonate.
Phosphates are developed
in rare instances-
common ore of zinc, is often changed superto smithsonite, hydrozincite, or calamine.

Such oxidized
ores are of greater value than unoxidized ones, because, although
Sphalerite, the
ficially
carrying a lower percentage of zinc, they occur in a more

concentrated form and yield more easily to metallurgical treat-
ment.
The chemical changes involved
in the
weathering of lead ores
are probably simple, but those of zinc are more complex than
formerly thought (3). They are given on p. 489.
was
more resistant to weathering and solution than

hence
when associated in the same deposit, galena is
sphalerite,
often found in the oxidized zone while sphalerite is removed.
Galena
is
ECONOMIC GEOLOGY
624
The soluble compounds produced by weathering may be cardown below the water level and reprecipitated as sulphides
(see reactions, p. 485), but authentic cases of secondary zinc and
ried
lead sulphides are rare.

Distribution of Lead
and Zinc Ores
in the
United States.
The
general distribution of lead and zinc ores is shown on the map,

Deposits of lead alone are found in the Appalachian
Fig. 212.
southeastern
Missouri. With the former there are also
and
belt,
number
of small veins in metamorphic rocks from Maine to

with the exception of some of the Virginia occurbut
Georgia,
FIG. 212.
Map
showing distribution of lead and zinc ores in the United States.

(Adapted from Ransome, Min. Mag., X.)
Zinc ores, almost free from

rences, they are of little importance.
occur
in
New
the
lead,
Jersey,
Virginia Tennessee belt, the Saucon
and
southwestern
Missouri. Lead and zinc
Valley, Pennsylvania
together, free from gold, silver, or copper are prominent in the
Upper Mississippi Valley. The mixed ores are prominent in the
Cordilleran region.
Desilverized Lead. 1 -
The important
localities supplying this

lead-silver
under
ores, but brief refertype
ence may be made to them here. Idaho is the most important
prducer, most of the ore coming from the Cceur d'Alene district.
In Utah much is obtained from the Park City district of Summit
of lead are described
1
This term is applied to those occurrences of lead associated with
smelting of the ore, the two metals are separated.
silver.
In the
GEOLOGIC CROSS SECTIONS

SCALE OF FEET
600
1200
Cambrian Limestone Franklin Limestone

and Quartzite
(white crystalline
(blue limestone)
Gneiss
Outcrop of Zinc
Ore Bodies
1800
Magnetite Outcrop
limestone)
GEOLOGIC MAP OF FRANKLIN FURNACE AND VICINITY

WITH SECTIONS OF THE ZINC ORE BODIES
PLATE LVII.
Geologic map of Franklin Furnace and vicinity, with sections of

the zinc-ore bodies.
(After Spencer, N. J. Geol. Sun.)
(625)
ECONOMIC GEOLOGY
626
County, the Bingham Canon and Cottonwood districts of Salt

Lake County, and the Tintic district of Juab County. Colorado's
main supply is yielded by the Leadville mines in Lake County
and the Aspen mines of Fitkin County, while smaller amounts are
obtained from Creede, Lake City, Ouray, and Rico.
(See LeadSilver references.)
lead is produced in the western states,

mentioned above. The important lead ores
of this region being closely associated with both igneous and
sedimentary rocks.
Comparatively
little
except in the three
Most
of the zinc
obtained in the
Rocky Mountain
states
is
from complex ores. Leadville is the most important producer,

and is described below together with some others of minor importance.
Contact-Metamorphic Deposits
United States.
known.
Few undoubted
Magdalena, N. Alex.
(42).
deposits of this type are

At this locality faulted
THE FRANKLINITC ORE BODY

BCMMfct
FIG. 213.
Model
of
Franklin zinc-ore body. (After Nason, Amer. Inst. Min.

Engrs., Trans. XXIV.)
blocks of Paleozoic limestone have been cut by granite-porphyry

dikes, the former containing roughly lenticular ore bodies, which
zone yield lead, silver and zinc, while in the

the
ore carries much sphalerite with a little galena
zone
sulphide
and chalcopyrite. Magnetite and specularite are present, w hi.e
the gangue has abundant epidote, pyroxene and tremolite, but
in their oxidized
little
is
garnet.
Sussex County, New Jersey (39-41). The output of these mines

second in importance to those of Mississippi Valley region.
LEAD AND ZINC

The
district
627
(PL LVII) includes two general areas situated close
together, the one called
Mine
Hill, at Franklin,
and the other
called Sterling Hill, at Ogdensburg, two miles farther south.

The ore deposits are in white crystalline limestone, which
is
bounded on the northwest by gneiss, and on the southeast by blue

Cambrian limestone along a fault line.
At Mine Hill (Fig. 213) the northerly pitching ore body lies in
the white limestone adjacent to its contact with the gneiss, and has
the shape of a trough, whose southern end appears to be doubled
over into an anticline. Magnetite deposits outcrop locally along
the limestone-gneiss contact, both adjacent to the zinc deposit,
and for a distance of more than one-half mile to the southwest.
The Sterling Hill (Fig. 214) deposit at Ogdensburg lies away from
the limestone-gneiss contact. The ore body is also a trough, which
FIG. 214.
Plan of outcrop and workings of the Sterling Hill ore body.

Spencer, N. J. Geol. Surv., Ann. Rept., 1908.)
(After
Both
pitches towards the east, and has a hook-like outcrop.
sides of the trough dip southeast; the exact extent of this ore
body is not known.

The ore minerals are principally franklinite, willemite (often
somewhat manganiferous) and zincite.
These, together with
,
tephroite, are practically the only metallic minerals at Sterling

Hill; but in the Mine Hill deposits, several other zinc- and
manganese-bearing minerals, mainly
silicates,
are not
uncommon.
Sphalerite occurs sparingly.

The gangue minerals are calcite, rhodonite, garnet, pyroxene, and
hornblende. The ore is granular, and some of it shows strong foli-
ECONOMIC GEOLOGY
628
usually a gradation from ore into country rock,

and while the ore appears to show a lamination corresponding with
that of the gneisses, the three dominant ore minerals mentioned are
There
ation,
is
not evenly mixed in
all
parts of the ore body.
At Mine Hill the run of mine ore has been estimated to contain from
19 to 22.5 per cent iron, 6 to 12 per cent manganese, 27 per cent zinc.
The franklinite has been found to contain from 39 to 47 per cent iron,
10 to 19 per cent manganese, and 6 to 18 per cent zinc the willemite from
1.5 to 3 per cent each of iron and manganese and the zincite about 5 per
;
cent manganese
At
and
iron.
Sterling Hill the. limestone lying between the outcropping ends

is mineralized, while inside the trough of
of the sides of the trough
ore there
is
a curved dike of hornblendic pegmatite, and on the con-
vex side of the dike, towards the ore, there are occasional developments of garnet, zinciferous pyroxene, and biotite.
We have in this district two zinc deposits, which are quite different
from all other known deposits of this metal, not only because of the
association of iron, manganese, and zinc in such ore bodies, but also
because of the form of combination of the zinc ores. Thus we have
the oxides franklinite and zincite, together with the silicate willemite,
occurring in great abundance, although very rare elsewhere.
The origin of these deposits is of unusual interest, for they not
only contain in abundance a number of zinc minerals, rare or unknown elsewhere, but many other mineral species as well.
Kemp
(39)
considers that the ore
solutions stimulated
by
was probably deposited by

and subsequently
intrusions of granite,
metamorphosed, but Wolff (41) suggests that they are contemporaneous in form and structure with the inclosing limestones and
hence older than the granites.
Spencer (40) argues that the present characters of the ore masses
and wall rocks originated contemporaneously because the two are
not sharply separated; so that the deposits must have been introduced either before or during the metamorphism of the containing
rocks and the igneous rocks which are now gneisses. He favors
the view that the lean ore of Sterling Hill was probably deposited
by magmatic waters which permeated and replaced the limestone,
and while the richer ore may have been formed in the same way,
there is also the possibility that the main ore layer at Sterling Hill
and the mass of ore at Mine Hill were injected bodily into the limestones, like igneous intrusions.
The pegmatites are evidently the source of
many
of the rarer
LEAD AND ZINC
629
minerals found in these deposits, because they are closely associated with them.
AVhile the origin of these deposits has undoubtedly been a
puzzling problem, one is forced to admit that it is perhaps as well
to class them as contact-metamorphic deposits, a view held by
both Vogt and Lindgren.

These ore bodies are of some historic
interest,
having been prospected
The Mine Hill deposits were worked

as early as 1640 and mined in 1774.
for iron ore as early as the beginning of the last century, the zinc mining
having begun about 1840.
The Sussex County ores, while chiefly valuable as a source of zinc, are
likewise of importance because of their iron and manganese contents.
Three products, viz. spelter, zinc oxide, and spiegeleisen, are made
from them.
The Mine
Hill ores are
now
yield three products, as follows

tion of zinc white, the residuum
by magnetic separators, which

Mainly franklinite, used in preparafrom this going to blast furnace to make
treated
1.
Half and half, containing franklinite, rhodonite, garnet,

with attached particles of the richer zinc minerals.
This contains a little more zinc than the franklinite, and while it can be
used for zinc white, the residuum is too high in silica for the spiegeleisen
furnaces.
3. Willemite product, which consists of willemite and zincite,
with calcite and silicates as impurities. The calcite is removed in jigs
and on concentrating tables, leaving material adapted to manufacture of
spiegeleisen.
and other
2.
silicates
high-grade spelter free from lead or cadmium.

The dust from the crushing and concentrating plant is also saved for
making zinc oxide. The following gives the approximate percentage of
each product and its zinc contents.
PRODUCTS OF MILL AT FRANKLIN FURNACE
ECONOMIC GEOLOGY
630
Deposits
Formed
at Intermediate
Depths
Most of the deposits of this type found in the

United States.
United States carrying lead or zinc, contain sufficient gold or
silver to be classed with the silver-lead (p. 658) or gold-silver ores
The most prominent example deserving notice in this
that of Leadville, Colo., but in recent years large quantities of blende have been obtained from Butte, Mont.
(See
under Copper), and considerable zinc also comes from the Cceur
(p. 675).
chapter
is
(See under Silver-Lead.)

d'Alene, Idaho, .district.
Leadville District, Colorado (6-12)
This region lies on the
western side of the Mosquito Range at the
.
headwaters of the Arkansas River in southcentral Colorado, while the town of Leadville is situated on the western spurs of the
range overlooking the Arkansas Valley. The
latter is bounded by the Sawatch Range on
the west.
The mines which have made

famous
Leadville
for its production of silver, gold, lead,
iron, and manganese are mostly high

on
the ridge and from 2 to 3 miles east
up
of the town, but in later years developments
have been spreading westward towards the
The district was formerly placed
valley.
lead-silver camps, but since the
the
among
zinc,
rich bodies of silver-bearing lead carbonate
have become exhausted a large tonnage is

obtained from the lead-zinc sulphide ore
bodies deeper down, and for that reason it
placed here, although it is not to be understood from this that other metals are not
is
produced there in quantity.

The Sawatch Range is an oval mass of
gneisses, granites, and schists on whose flanks
rest the
Cambrian and
later sediments, dip-
ping away from the range on
The Mosquito Range

14,000 feet)
rocks, with
all sides.
(elevation 13,000 to
mainly of Paleozoic
composed
some Mesozoic deposits on
is
its
eastern flanks, while between these beds are
PLATE LVIII
FIG.
View from top of Carbonate Hill, Leadville, Col., looking towards Iron
The valley in center ground marks position of the Iron fault. Shaft house
that of Tucson shaft, and ridge in distance fault scarp of Mosquito Range.
1.
Hill.
is
(H. Ries, photo.)
FIG. 2.
View from south end of Carbonate Hill, Leadville, Colo., overlooking
Sawatch
California Gulch in foreground, and town of Leadville in the valley.
Range in distance. (H. Ries, photo.)
(631)
ECONOMIC GEOLOGY
632
sills
and
laccoliths of igneous rocks,
whose intrusions occurred be-
fore the uplift of the region.
This uplift was formed by an east-to-west thrust which pushed

the beds up into folds against the Sawatch Range and later faulted
them
(Fig. 215).
In consequence, therefore, of folding, faulting, igneous intrusions,

and detrital material, the structural geology of Leadville affords a
somewhat complex problem.
The
geological section best
as follows
LOCAL NAME
shown
in
Carbonate
Hill
perhaps
is
LEAD AND ZINC
633
copper sulphides carrying silver and gold, the proportions of the

several metals varying in different parts of the district.
For some years the oxidized ore bodies of cerussite and cerargyrite in a matrix of iron and manganese oxide formed the mainstay of the camp, but the practical exhaustion of these led to
deeper mining and the discovery of the large sulphide bodies at

lower levels.
Fio. 216.
Vertical section along line

(After Argall, Eng.
AB,
Fig. 186.
and Min. Jour.,
Tucson
shaft, Leadville, Col.
LXXXIX.)
While the sulphide ores became an important source of supply,

as late as 1911 (7, 9) there were discovered in the blue and
still,
also white limestone great quantities of zinc carbonate of replacement origin. P. Argall has also noted the presence of great
masses of manganiferous siderite in the limestone associated with

intrusive gray porphyries
The camp now
is
(8).
turning out a large tonnage of lead and
zinc sulphides which may carry gold and silver, zinc carbonate,
manganese ores from oxidized deposits on Carbonate Hill, some
copper sulphides, and some bismuth ores.
ECONOMIC GEOLOGY
The
origin of these ores has been discussed
Emmons and Blow

Emmons,
being
in his classic
among
by
several geologists,
the earlier ones.
monograph on
this district (4) expressed
GEOLOGICAL PLAN
ON PLANE OF
5TH LEVEL
EEl
FIG. 217.
Geologic plan of
and workings, Tucson shaft, Leadville, Col.

and Min. Jour., LXXXIX.)
fifth level
(After Argall, Eng.
the following views regarding the origin of the ore deposits: (1) that
they have been derived from aqueous solution (2) that this solu;
tion
came from above;
(3)
that the ores derived their metalLc con-
tents from the neighboring eruptive rock.
He
further adds that
LEAD AND ZINC

these statements are not intended to clen3r the possibility that the
may have originally come from depth, nor to maintain that
metals
they were necessarily derived entirely from eruptive rocks at present

immediate contact with the deposit. (4) The ores were deposited
in
by replacement
of the country rock.
(5)
They
are of later age than
the porphyry sheets, but were introduced before the faulting of the
region occurred.
These views are not agreed to entirely by ail persons familiar

district, and there is a tendency among many engineers
who have a more or less
with the
intimate knowledge of the

region to feel that the ores
may have been

by
brought in
solutions ascending di-
rectly
from the granite, a
theory which they regard as

being strengthened by the
finding of fissure ores in the
Cambrian quartzite
(tigs.
216, 218).
T
We
-,-v
/.A
must remember,
COUrse, that since
of
Emmons'
WOrk was done the district

has been greatly and more
'
and blende; B, galena; C,
pyrite
Di
open cavity; E
mud
deposit;
Quart21tes
FJQ 218 ._ Ca vities in Cambrian quartzite,

Tucson shaft, Leadv.lle, Col. (After Argall.)
deeply developed, thus affording apportunity for more extended

investigation.
The plan
(shown at the top of page 636) shows graphically

the course of treatment of Leadville ores from mine to market.
The quantity
of the several classes of ore
produced in 1914 was:
short
Siliceous
tons; sulphide ores,

gold-silver ores, 33,000
307,559 short tons; oxide ores, 192,143 short tons, of which
113,881 were zinc carbonate.
Even in former years Leadville was a mining camp of great importance,

having indeed given Colorado its first serious start as a mining state. From
an area of about a square mile the output of silver was for a number of years
greater than that of any foreign country except Mexico, and during the
same period the production of lead was nearly equal to that of England and
greater than that of any European country excepting Spain and Germany.
Although regarded originally as a
nearly fifteen years ago, and
1
From U.
is
'silver
camp,
it
really ceased being such

of at least eight
now an important producer
S. Geol. Surv.,
Min. Res., 1911.
ECONOMIC GEOLOGY
636
Hine Month
Old
J ^
Mine Mouth
Mine Mouth
Mine Mouth
Mill
Wet
Dum
Mine Mouth
Mine Montfl
Jl
Jl
JUl
Jl
Enriched lead furnace matte
T
(40-45/1
copper)
Copper
refineries
Spelter and zinc

oxide markets
'
Base bullion
Ea8tern_refineries
metals, of which five or six are sometimes all obtained from the same group
It will thus be seen that the successful marketing of one may
of properties.
Leadville began as a gold camp in 1860, when a placer

deposit of gold was found in a gulch near there and several million dollars'
worth of metal were extracted, resulting in the establishment of a flourishing
town called Oro, which, however, soon lost its importance when the gold
affect all the others.
began to be exhausted. Not until 1875 was the carbonate of

since been so important, actually recognized.
Deposits Formed Near Surface
United States.
Several ore districts
referred to under this head.
Thus
district carry considerable galena
(lla),
and cut volcanic
rocks.
Colorado there are found
lead,
the west
of
certain veins of the
and zinc
Again
which has
may
in a quartz
in the
Creede
be
Lake City
gangue
district of
fissure veins in rhyolite, also
showing
lead and zinc with a gangue of quartz, barite and fluorite (10a).
Others carrying a stronger content of the noble metals are referred
to
under Lead-Silver and Gold-Silver.

Deposits in Sedimentary Rocks, Unrelated to Igneous Ones
Deposits of lead and zinc in sedimentary rocks, and showing

no relationship to igneous rocks form a widely distributed type,
whose association with calcareous rocks, as limestones, dolomites
and calcareous shales is most pronounced.
1
These
localities are
not strictly lead-zinc producers.
PLATE LIX
FIG.
FIG.
1.
View
of valley at Austinville, Va.

of mill tailings on right.
Zinc ores in
hill
at
left,
white heap
(H. Ries, photo.)
2.
Old oxidized ore workings at Austinville, Va. The ore was in residual
clay which formerly covered these limestone pinnacles.
Sulphides underlie
these.
(H. Ries, photo.)

(637)
ECONOMIC GEOLOGY
638
The primary ore minerals are galena and blende, while above
them in the weathered zone are the usual oxidation products.
Iron sulphide may often be present, and is undesirable, but
gold and antimony are rare, and the deposits are with few exThe blende may contain small
ceptions non-argentiferous.
quantities of cadmium, or the latter as the sulphide, greenockite may be present as a secondary mineral.
Nickel and
cobalt are found in small amounts in the southeastern Missouri
ores.
Dolomite is a common gangue mineral, and chert is often
present.
The
deposits,
which are not of great depth,

form disseminations.
may
fill
solution
cavities, fault fissures, or
Most geologists believe that the ore bodies of this type have
been formed by meteoric circulation.
United States.
In the United States this type of ore deposits
is especially important in the Mississippi Valley region, -and also
in southwestern Virginia and east Tennessee.
Zinc and some lead ocVirginia-Tennessee Belt (50-53,59).
cur in a belt extending from southwest Virginia into Tennessee.
Section of Bertha zinc mines,
FIG. 219.
Wythe
Co., Va.,
showing irregular sur-
by residual clay-bearing ore. (After Case, Amer.

Trans. XXII.)
Compared with Plate LIX, Fig. 2.
face of limestone covered

Inst.
The
Min. Engrs.,
ores
limestone,
are
intimately
associated
and show two types,
viz.:
Cambro-Ordovician
with
(1)
secondary or weathered
including calamine, smithsonite, and

are concentrated in the residual clays next
ores,
weathered surface of the limestone
and
(2)
pyrite,
primary
belonging
ores, including
to
the
(Fig.
Avhich
irregular
219 and LIX, Fig. 2)
sphalerite,
disseminated
cerussite,
to the
galena,
and some
replacement
breccia
LEAD AND ZINC

type
(Fig. 220),
and which have been
639
localized
along the crushed and faulted axes of the folds.
by ground waters
The gangue miner-
Section showing replacement of limestone by sphalerite and galena,

(After Watson, Va. Geol. Surv., Bull. I, 1905.)
FIG. 220.
Austinville, Va.
Fluorite is known,
als are chiefly calcite, dolomite, and some barite.
and quartz may occur in the form of chert. One deposit only, in
Albemarle County, is
found in schist, and is
closely associated with
igneous rocks.
Pennsylvania
-
The
Saucon
(48, 49).
Valley
deposits promised at one

time to become promi-
nent producers, but have

not,
owing more to geoconditions than
logical
actual scarcity of ore.
Mississippi Valley
Lead and Zinc Region.
This region contains
Map of Ozark region.
PIG. 221.
(After Bramier,
Eng. and Min. Jour., LXXIII.)

viz.: (1)
(3)
and
the Ozark Region,
^^
somewhat Sepaof deposits>
upper Mississippi Valley area,

chiefly in northern Arkansas, Kentucky
outlying districts,
Of these the
Illinois.
Ozark Region
several
(5, 23,
(2)
the most important.

This region, which lies mostly in
first is
27-36).
ECONOMIC GEOLOGY
Missouri
(Fig. 221),
but also in-
cludes portions of Arkansas, has

four districts, viz.: (1) the south-
western Missouri, which

tially lead-producing,
5Q
is
essen-
and has been
described on an earlier page; (2)

the Central Missouri, containing
small ore bodies with both lead and
zinc (28)
(3)
the Missouri-Kansas,
or southwestern Missouri, mainly a
zinc-producing area;
(4)
northern
Arkansas (l, 2), producing chiefly

zinc, with some lead.
The third, or most important
one, will be specially referred to.
The Ozark uplift or plateau is a
low, rudely elliptical
222, 223)
dome
(Figs.
lying mostly in southern
Missouri and northern Arkansas.

.2 '3
The Boston Mountains form the

southern boundary, while it merges
into prairie on the west and north,
and the Gulf Plains on the
east
and
southeast.
The rocks are mostly of sediment.5
>
ary origin, but pre-Cambrian granand porphyry form some of the
ites
peaks of the
St.
Francis Mountains.
The Cambrian and Cambro-OrdoJ<3
vician dolomites, and limestone and

sandstones underlying the central
Ozark
area, surround these mountains concentrically, and are in turn
flanked successively by Devonian

to Pennsylvania!! rocks.
G
c
_
S
is
This
Joplin Area (27,31-34).
the most important area in the
Missouri-Kansas
district,
and the
generalized geological succession is

shown in the accompanying diagram
(Fig. 224).
3 o
LEAD AND ZINC
641
The
ore deposits of the Joplin district occur in large but very

irregular masses of chert and limestone, which are unusually brecciated
and cemented by, or impreganted with, dolomite,

FORMATION
jasperoid,
CHARACTER OF ROCKS
Drab to black shale and gray to

buff sandstone with occasional
Cherokee
beds of
coal.
-UNCONFORMITY
Light to dark shales and shaly

and oolitic limestone with
some massive soft to hard
Carterville
sandstones.
UNCONFORMITY
(
Massive homogeneous bed of
Short Creek
oolite
member,)
oolitic limestone.
Limestone,
Boone
line,
in large part crystal-
with interbedded chert.
Heavy -bedded, solid
(Grand Falls
member.)
chert.
chert
FIG. 224.
Generalized geologic section of the Joplin
district.
(U. S. Geol. Surv.,
All. Fol. 148.)
and carry considerable amounts of sphalerite,

and iron sulphide. Of subordinate importance are chalcoWeathering develpyrite, greenockite, barite and other minerals.
ops oxides, carbonates, sulphates, and silicates of many of the
above. They are found in the Boone formation and show a close
association with certain forms of fracturing and brecciation.
Jasperoid, which is the commonest gangue material, forms a
cement of chert, breccias or intercalations in practically undisclacite or sphalerite,
galena,
ECONOMIC GEOLOGY
642
turbed beds in sheet ground; it is usually of a dark gray to

nearly black color when fresh, and the microscope shows it to be a
Some
fine-grained allotriomorphic aggregate of quartz (Fig. 225).
have thought it to be a mud-like deposit that was later silicified,
but it is more probably a siliceous replacement of limestone.
Photo-micrograph of jaspcroid, showing fine granular aggregate of

quartz, with sphalerite (shaded) and dolomite, the latter including minute quartz
FIG. 225.
crystals.
53.
(After
Smith and Siebenthal.)
The two important forms of ore body are runs and sheet ground.
The runs are irregular, usually elongated, and in places tabular
and inclined bodies
of ore, associated with breccias produced, ac-
cording to Smith, by minor faulting.

and are comparatively shallow. It
They may be 1050 ft.
wide,
thought they represent ore

upper part of the Boone
formation (Fig. 224) during a period of pre-Pennsylvanian erosion.
Sheet ground deposits, which occur in the Grand Falls chert
deposition in sink holes
formed
is
in the
member
of the Boone formation are tabular ore bodies, often

The sulphides occur
of great lateral extent, and 6 to 15 feet thick.
in part along bedding planes of cherts and in part in breccias
resulting from slight folding and faulting of the bedded rocks.
In the breccias the ore occurs as a cement or in jasperoid, while

in the
is
bedding planes
it is
in solution cavities or in jasperoid.
The sheet ground averages lo-êr

more uniform in character and being
in
all
ore content than the runs, but

at one level is more easily mined
PLATE
FIG.
1.
View
in Joplin district near
Webb
LX
City,
Mo.
(Photo from F, C. Wai-
lower.)
FIG.
2.
Chambers
in
Disbrow Mine, near Webb City, Mo. These include both

"
"
broken ground
above.
(Photo from F. C. Wai-
sheet ground and the
(643)
ECONOMIC GEOLOGY
644
Ore running 6 per cent is regarded as good, but when it falls to 2| per cent
hardly pays to work it.
In the runs the galena is most abundant above, while the sphalerite
occurs in the middle or lower portion, but in the sheet ground there is no
such vertical separation.
The Joplin district is a most important producer of zinc, and while
the content of this metal is low in the ore as it comes from the mines,
still concentration raises it to about 58 per cent.
The average tenor of
lead is .5 to 1 per cent and of iron from 1 to 2 per cent.
It assays about
30 per cent sulphur, and the remainder, besides a little cadmium, is silica.
An analysis representing the average of 3800 carloads of blende shipped
from the Joplin district in the first part of 1904 is given by Ingalls as
Zn, 58.26
Cd, .304
Pb, .70
Fe, 2.23
Mn, .01 Cu, .049 CaC0 3
1.88; MgCO 3 .85; Si0 2 3.95; BaSO 4 .82; S, 30.72; total 99.773.
it
Most of the theories of the origin of these ores

Origin of the Ores.
agree in considering that their concentration has been caused by
circulating meteoric waters which have collected the ore particles
from the limestones, although in one instance at least they were
thought to be associated with igneous intrusions (35).
Analyses of the limestones (36) show amounts of from .001 to
.015 per cent of lead and zinc in the Cambro-Silurian magnesian
limestones and Archaean rocks in the southeastern part of the
Ozark region, and from .002 to .003 per cent in the Lower Carboniferous limestones.
These averages, expressed in different form, give 87 pounds of

galena per acre in a one-foot layer, and 261 pounds of blende in the
same volume of rock.

The most detailed study
made by
Siebenthal
(33)
of the genesis of these ores has been

points out that the erosion of the
He
Pennsylvanian shale from the central portion of the uplift exposed

the Cambro-Ordovician and Mississippian rocks, down the dip of
which the surface waters flowed, and ascended again on the inner
margin of the Pennsylvania shale which still covered the flanks
This water charged with carbon dioxide took the
of the up^ft.
sulphides into solution as bi carbonates. As the solutions rose in
the broken, cavernous ground in the Mississippian limestones, the
CO 2 escaped and the metals were precipitated as sulphides by the
hydrogen sulphide
still
remaining in solution.
There has been some difference of opinion among geologists who have
studied these ores in the past, and therefore a brief resume of these views is of
interest partly because they indicate what varied conceptions may be based
on the same evidence.

A. Schmidt l believed that dolomitization
1
Mo.
Geol. Surv.,
I,
of the cherty limestones
1873-1874.
caused
LEAD AND ZINC
645
a shrinkage of the rock, and was accompanied by a deposition of the ore.

Subsequent solution of the limestone caused a collapse of the residual chert,
followed by further deposition of ore.

Haworth 1 suggested that after the chert and limestone were greatly
fractured and dislocated, the sulphides were deposited, but that the deposition
secondary chert had begun before sulphide deposition ceased.

Winslow (36) thought that the breccia-filled caverns in the country rocks
were formed by the percolation of surface waters, and that the metalliferous
minerals were leached out of the overlying rocks by surface solutions and
of
deposited in the breccias.
Jenney
(31),
however, believes the ores to have been deposited by ascend-
ing solutions.
Bain and Van Hise (27) after studying the district .concluded that both
ascending and descending waters were active. They also expressed the
view that while the more important circulations have occurred in the Cambro-Silurian limestones and those of the Mississippian or Lower Carboniferous series, still the concentration process has been often repeated in many
different horizons
and at
different depths.
According to their theory, then, the chemical changes which took place
in the primary concentration of the ores were the oxidation of sulphides
(in
and
the limestones) to sulphates, the transportation of these in solution,

their reprecipitation as sulphides in favorable localities.
The localiza-
tion of the ore bodies has been due to the presence of fissures which permitted
the mixing of the ore-bearing solutions, but the circulation of the latter has
been limited in many instances by impervious beds of shale, and organic
matter has served as a reducing agent.

In the section presented in the Ozark region, the Devono-Carboniferous
shales and the undifferentiated Carboniferous shales afforded impermeable
The former, where not faulted, held down the ascendbarriers to circulation.
ing solutions; but where absent or fissured, the solutions from the underlying Cambro-Silurian formation were able to pass upward into the Missisippian and impregnate them.
The Cambro-Silurian ores were first concentrated by deep circulation,
and formed the disseminated ores. Later, when erosion cut away the DevonoCarboniferous capping, further concentration took place by descending solutions, giving rise to the ore bodies in crevices, breccias,
and
synclines.
Two
concentrations have occurred in the Mississippian limestones.

Smith (34) agreed with Van Hise and Bain that the immediate sources
were the various limestone formations below the Pennsylvanian.

that the surface waters entered the Mississippian and CambroSilurian exposures to the south and east.
Flowing westward along these
beds, they then pass upward through fractures into the Mississippian 1 meBoth flows are believed to have
stones, mingling with the waters from these.
leached the smaller quantities of lead and zinc ores from the limestones through
which they passed.
of the ores
He assumed
Precipitation of the ore occurred in the brecciated portions of the Boone

formation (Fig. 224), and was caused by hydrocarbons which reduced the
1
Contribution to Geology of Lead and Zinc Mining Districts of Cherokee Co.,
Kansas.
ECONOMIC GEOLOGY
646
sulphates to sulphides. These hydrocarbons were set free by the dolomitization of the limestone, while CO 2 was set free by reaction between the hydro-
The CO 2 thus liberated

carbons and the dissolved metallic compounds.
attacked some of the adjacent limestone, a part of which became replaced by
silica.
The
repetition of this cycle gave a continuous formation of dolomite,

and disseminated blende. Secondary concentration of the ore may
jasperoid,
have occurred.
There are certain points
of similarity in the two preceding views.

Quite different, however, is the theory worked out by Buckley and Buehler
(29).
According to them there was an elevation of the region after the deposition of the Burlington limestone, followed by its extensive erosion and dis-
section.
As a
result of this process, great surface breccias of residual chert
were probably produced on the hillsides and along the edges of the stream
Subsidence during the Coal Measures period caused their burial
valleys.
under Pennsylvanian (Middle Carboniferous) sediments, where they now lie
and have been identified by some (Bain) as fault breccias, but in reality are
due to weathering.
They also of necessity lie along the horizon of what is now a marked
unconformity, giving the semblance of faults. The metals and their ores are
believed by these authors to have been derived from the overlying Pennsylvanian rocks, through the agency
oi
descending surface waters.
Central Missouri district, containing small deposits of both lead

and zinc. In this area the ore as far as exploited occurs rather
in vertical crevices or chimneys than in breccias.
The northern Arkansas
district,
but partly developed, has
many
rich ores, occurring as bedded deposits (disseminations), veins

(in faults or filling breccias), or as replacements (4, 5).
Southeastern Missouri
(30, 36).
The disseminated
lead ores
mainly within St. Francis, Washington,

and Madison counties, the geologic section involving the following
formations
of southeastern Missouri
lie
Potosi dolomite.
Doerun argillaceous dolomite.

Derby dolomite, thickly bedded.
Upper and Middle

Cambrian.
Davis formation,
with thin beds
300
60-100
ft.
4-
ft.
40ft.
chiefly shale
of limestone,
dolomite and limestone conglomerate.

Bonneterre,
mainly magnesian
limestone with sandy dolomite
170
and shale.
Lamotte sandstone.
305
200
ft.
ft.
ft.
or less.
Unconformity.
Pre-Cambrian.
The abstract
and rhyolite with intruGra_nite

sive diabase dikes.
of this district
was kindly furnished by Dr.
P. Buckley.
LEAD AND ZINC
647
While the sedimentary series as a whole has retained its originally

approximately horizontal position, there are numerous local dips,
some of which may be as much as 45. The numerous small faults
of the district are roughly groupable into a northeast-southwest
and
a northwest-southeast system.
Most of
the faults are of normal type and usually
have a throw of
less
than 100
feet;
but
those of the major zones show aggregate
displacements of 700, 600, and 400 feet

respectively.
The
ore bodies of the district usually
lie
and while some galena

of massive crystallized type has been mined
with profit from the Potosi, and upper part
in pitching troughs,
LEGEND
of the Bonneterre, the disseminated dewhich are the main source of the
CHLOnlTIC LIMESTONE
posits,
lead ore in the district at the present day,

occur mainly in the lower half of the BonneCHLOnlTIC SHALE
terre.
In the so-called disseminated lead-ore

bodies, seven types of occurrence are noted,
which the
of
first is
the most important:
disseminations in dolomite, shale, and

chloritic rock
(2) horizontal sheets along
(1)
(3) filling or lining
bedding planes;
the
walls of joints; (4) in cavities, vugs, and

similar openings, sometimes embedded in
mixed with
soft blue clay or
FIG. 226.
half
foot
Four and one (6)

section show-
mg
(5)
and
m d
occurrence of ore
Bonneterre
limestone,
Doe Run, Mo.
calcite
in shale
along fault planes;

in cubes and aggregates of cubes in red
pyrite;
(After
Buckley MO. Bur. Geoi.

Mm., IX.)
fim
channels and large openings
*
along fault zones (7) as cerussite in decomposed dolomite.
;
The disseminated
ea d-ore bodies are in
part the result of the abstraction of lead

from waters circulating along channels and bedding planes in their
journey from the surface to the Lamotte sandstone, and in part
from
solutions, under hydrostatic pressure, which rise along channels

extending upward into the dolomite, from the underlying sand-
stone.
In the Bonneterre formation the conditions were favorable for
ECONOMIC GEOLOGY
648
the reduction of the metallic
salts, resulting in their
precipitation
as ore bodies.
The
At the
details of the deposition are considered to
be about as follows
an oxidized zone containing galena, which is being

abstracted by surface water percolating down towards the Lamotte sandstone, which on account of its high porosity serves as a storage reservoir
Between these two zones is the
of water- containing lead in solution.
Bonneterre formation, with its carbonaceous and chloritic reducing agents,
and in which formation the lead has been deposited.
Channels furnish connecting ways between the oxidized zone and the
sandstone, and the rocks along these have been and are being oxidized, persurface there
is
mitting the direct transference of oxidizing solutions, carrying lead.

Some water may have also entered the sandstone by other channels.
The dolomite, which is now oxidized along the channels traversing it,
was at one time of a reducing nature, and the deposition of the galena
found in the rock adjacent to these passageways must have occurred
before the dolomite was oxidized. At such time any oxidizing solutions
carrying lead which penetrated the lower horizon of the Bonneterre formation must have been brought in from other areas, chiefly through the
rock outcropping near the area of igneous rocks. The galena in the
crevices may have been introduced in part by ground water from the surIt is
face, and in part from water rising from the Lamotte sandstone.
thought that the ore bodies in the Bonneterre are mainly subsequent to
the establishment of zones of communication along the oxidized channels.
The original source of the lead was the igneous rocks, its transference to
the sedimentary formation having taken place during successive periods
of decomposition by the surface and ground water circulations, the waters
carrying the metallic compounds down into the sea where they became
incorporated in the sediments then forming.
This area embraces southwestern

Upper Mississippi Valley.
Wisconsin (63), eastern Iowa (20, 21), and northwestern Illinois
(11), but the first -named state contains the most productive territory. The section in theWisconsin area (63), which may be taken as
typical, involves the following formations, beginning at the top:
FEET
Pleistocene
7
Loess, alluvium, and soil
Silurian
50
Niagara limestone
f Maquoketa shale
160
Galena limestone
230
Ordovician
Platteville limestone (Trenton)
55
^
St. Peter sandstone
70
Lower Magnesian limestone
200
Cambrian
Potsdam sandstone
700
Pre-Cambrian
Crystalline rocks
I
*-
A bituminous shah
of the Galena,
layer,
and below
known
as the
oil rock,
occurs at the base
or at the top of the Platteville, is a finegrained limestone called the glass rock. While the series as a whole
shows a very gentle southwest dip, there are a few low folds.
it,
LEAD AND ZINC

The
649
ores occur in crevices (Fig. 227) in the dolomite or as disIn the former the order of deposition
seminations in certain beds.

or arrangement
and
is (1)
marcasite, (2) sphalerite with
some
galena,
galena.
The crevice deposits (Fig. 227) form the most important source
of the ore, and consist commonly of a vertical fissure, which at its
(3)
lower end splits into two horizontal branches called flats, while these
in turn pass into steeply dipping fissures termed pitches.
Galena
commonly predominates
in
the crevices,
while sphalerite occurs
3TRENTON
3ulMESTONE
^J GLASS ROCK
fissure
FIG. 227.
Section showing occurrence of lead and zinc ore in Wisconsin
ore in flats and pitches, and disseminated ore in wall rock.
(After Chamberlin.)
;
in great
abundance lower down. The main crevices extend approxiand west, but there are other less important intersect-
mately east
ing fissures.
The chief ore bodies lie in the lower part of the Galena limestone.
Flats unconnected with pitches are found just above the oil rock at
base of Galena, and in the lower part of the glass rock, while disseminated deposits may occur in the same position as these
even in the oil rock.
flats,
or
The ores below the ground-water level are galena, sphalerite, and
iron sulphide (usually marcasite), while above this they are galena,
Calcite is a common gangue mineral.
smithsonite, and limonite.
In explaining the origin of the ore bodies some have claimed (63)
that the metallic minerals were gathered by circulating meteoric
waters from the Galena limestone; these waters entered the limestone probably from the northeast, where the overlying shales had
been eroded, and moved to the southwest. The ore was precipi-
ECONOMIC GEOLOGY
650
tated in crevices as sulphides, either because of a reducing action

exerted by bituminous matter present in the rocks or by hydrogen
sulphide.
Surface waters descending crevices have produced a secondary

concentration, which has resulted in a separation of the zinc and
galena, accompanied by a
transferal of much of the
former to lower
levels.
More
recently Cox (18)

has expressed the opinion
that the
shale
Maquoketa
was the probable source of

the lead and zinc.
Lead was
discovered in the
L'pper Mississippi area as early as

1692, and the first mining was
done
in
early
work was
Dubuque
in 1788.
The
restricted to lead
mining entirely, the zinc ores be-
The increased
ing disregarded.
price of zinc in later years led to
opening of deposits below
water level, and a continued
production of zinc. Mechanical
concentration methods have been
the
introduced,
IS
013
Old
Structural
DlriSi
rkiuga
Contours
Map of a portion of Wisconsin

lead and zinc district, showing strike of
crevices, underground contours of Galena
FIG. 228.
limestone,
and
underground
workings.
(After Bain, U. S. Geol. Sure., Bull. 294.)
and while the galena
can be separated quite thoroughly

from the sphalerite and marcasite,
the last two are parted with

On account of the
difficulty.
presence of marcasite in most of

the mines, the zinc ores of this
district
comn and
a lower price
than those from other areas.
Both
electrostatic
and
electro-
magnetic separation have been used on these ores with good results. Thus
working on a material that assays 30 per cent zinc and 20 per cent iron, the
zinc product assays 56 per cent zinc and 4 per cent iron, while the iron product gave 39 per cent iron and 5 per cent zinc.
The crude ore yields from 5 to over 20 per cent concentrates, and these in
1914 averaged 35.0.5 per cent zinc.
Foreign Deposits.
Europe contains two important lead-zinc
districts,
The first of these is the

to the Mississippi Valley type.
Moresnet district in Belgium and Prussia, where the ores, which carry sphalerite, galena, iron sulphide and calcite are associated with faults in the Devon-
somewhat analogous
ian
and Carboniferous limestones, and have been deposited

1
Vogt, Krusch und Bcyschlag,
Lagerstiitten.
in cavities or
by
LEAD AND ZINC
651
replacement. Considerable oxidized ore was obtained from the upper part
of the ore bodies.
The second of these, located in Silesia, Prussia, is among the world's leading
producers.
The
ore here appears to form replacements in dolomitized Tri-
assic limestone at
two horizons, the lower one yielding
and the upper one smithsonite.

Other European occurrences in limestone are those
sphalerite, galena
and
marcasite,
of Raible
and Bleiberg
in Austria; Santander, Spain, Sardinia^ etc.
Uses
of
Lead and
Both of these are important base metals;
Zinc.
although in value of production they rank below gold, silver, copper,

and iron, neither do they come into competition with these, for
they lack the high tenacity of iron and steel, the conductivity of
copper, and the value resulting from scarcity possessed by gold and
silver.
They are of value, however, on account of their high mallea-
and the application of their compounds

Lead finds numerous uses
bility
Uses of Lead.
for pigments.
in the arts, the
most
important
Litharge, the oxide of lead, is used
not only for paint, but also somewhat in the manufacture of glass,
although red lead is more frequently employed instead.
being for white lead.
further use of lead
is
for
making pipe
for
water supply, sheet
lead for acid chambers, and shot.
formed by lead are type metal (lead,

and
bismuth, with copper, or iron), white metal,
antimony,
organ-pipe composition, and fusible alloys used in electric
Among
the alloys
lighting.
In addition to these, the acetate, carbonate, and other compounds are used in medicine. In smelting, lead is used to collect the gold
is
and
silver,
and the bulk
of the lead of
commerce
obtained as a by-product in the smelting of the precious
metals.
Uses of Zinc.
partly owing to
it
used for a variety of purposes,

and secondly, because
can be rolled into thin sheets. In this condition it is used
Metallic zinc
is
its slight alteration in air,
extensively for roofing and also for plumbing, and as a coating

to iron this metal is extensively called for in galvanizing.
It
is
also used for cyaniding gold.
of the most important applications is for making brass, which

ordinarily composed of from 66 to 83 parts of copper and 27 to
34 parts of zinc. The composition varies, entirely depending on. the
One
is
it is to be put, and, with the variation in proportion,

the color becomes more golden, or whiter, according as the percentage of copper is increased or decreased. With an increase in the
use to which
ECONOMIC GEOLOGY
652
amount
of zinc, the alloy
becomes more
fusible, harder,
and more
brittle.
White metal is an alloy of zinc and copper in which zinc predominates, and which is often employed for making buttons.
Imitation gold is also made by alloying zinc with a predominance
of copper, varying from 77 to 85 per cent of the mass, and this is
"
"
for gilding.
Zinc is also made use of
in common use as
gold foil
in the construction of electric batteries.
German
use
is
for
Zinc
is
silver has 60 parts copper, 20 zinc, and 20 nickel.

mathematical and scientific instruments.
used wholly or in part as the base of four pigments,
zinc oxide, leaded zinc oxide, zinc-lead oxide,
Its
viz.
and lithophone.
All
made
directly from the ore, and the first three usually

Zinc oxide is the most important of the four. Lithophone is
are.
an intimate mixture by chemical precipitation of zinc sulphide and
barium sulphate.
Production of Lead and Zinc.
The production of refined lead
and spelter in the United States from 1875 to 1914 are given
below. Other statistics of production are given in the tables on
pages 653 to 655.
of these can be
The imports
of manufactured, block, and pig zinc amounted to

in 1912; $632,036 in 1913, and $84,120 in 1914.
$1,363,884 worth
The
total
amount
of zinc ore
valued at $149,503.
manufactured zinc
The
in 1914
imported in the year 1914 was
total value of the exports of ore
were valued at $9,381,050.
and
The im-
ports of zinc oxide in 1914 amounted to 2,629 short tons, while

the exports in that same year amounted to 15,592 short tons,
valued at $1,408,525.
The total value of lead imported in 1914 was $504,978, while

the exports were valued at $4,501,674 for the same period.
PRODUCTION OF REFINED LEAD AND SPELTER IN THE UNITED STATES,
1875 TO 1914, IN SHORT TONS
YEAR
LEAD AND ZINC
653
PRODUCTION OF PRIMARY SPELTER IN THE UNITED STATES IN 1912-1914,

APPORTIONED ACCORDING TO SOURCE OF ORE, IN SHORT TONS
SOURCE
ECONOMIC GEOLOGY
654
The Canadian imports of zinc blocks, pigs, and sheets in 1914

were valued at $189,785, and spelter at $551,031.
SOURCES OF PRIMARY LEAD SMELTED OR REFINED IN THE UNITED STATES,
1912-1914, IN SHORT TONS
SOURCE OF ORE
LEAD AND ZINC

THE WORLD'S PRODUCTION OF
655
SPELTER, 1912-1913, IN SHORT TONS
ECONOMIC GEOLOGY
356
11. Emmons and Irving,

(Creede.)
(Downtown district, Leadville.) lla. Irving
320, 1907.
and Bancroft, U. S. Geol. Surv., Bull. 478, 1911. (Lake City.) 12.
Moore, Econ. Geol., VII: 590, 1912. (Recent developments, Leadville.)
Larsen, Ibid., Bull. 530: 42, 1913.
Ibid.,
Bull.
22d Ann. Rept., II: 229, 1901. (Rico

Lindgren, U. S. Geol. Surv., 20th Ann. Rept., Ill:
(Wood River district.) 15. Schrader, U. S. Geol. Surv.,
190, 1900.
20th' Ann. Rept., Pt. Ill: 187.
Illinois: 16. Bain, U. S. Geol. Surv.,
13.
Ransome, U.
Idaho:
Mts.)
S. Geol. Surv.,
14.
17. Bain, Ibid., Bull. 225: 202, 1904.

(N. W. 111.)
(N. W. 111.) and Bull.
19. Cox, Econ. Geol., VI: 427 and 582, 1911.
(Origin
Bull. 246, 1906.

18.
(111.)
16:
Cox,
24, 1911.
111.
Up. Miss. Val. ores.) Iowa: 20. Bain, U. S. Geol. Surv., Bull. 294, 1906.
21. Calvin and Bain, la. Geol. Surv., X: 370, 1900.
22. Leonard, la.
Geol. Surv., VI: 10, 1897.
Kansas: 23. Haworth and others, Kas.
Geol. Surv., VIII, 1904. Kentucky: 24. Miller, Ky. Geol. Surv., Bull.
1905.
25. Ulrich and Smith, W. S. T., U. S. Geol.
(Cent. Ky.)
2,
Prof. Pap. 36, 1905.

Massachusetts: 26. Clapp and Ball,
Econ. Geol., IV: 239, 1909. (Newburyport.) Missouri: 27. Bain,
Van Hise and Adams, U. S. Geol. Surv., 22d Ann. Rept., II: 23, 1901.
28. Ball and Smith, Mo. Bur. Geol. Min., 2d ser., I, 1903.
(Central
Mo.) 29. Buckley and Buehler, Mo. Bur. Geol. Min., 2d ser., IV, 1905.
(Granby area.) 30. Buckley, Mo. Bur. Geol. Min., IX, 1908. (S. E.
Mo.) 31. Jenney, Amer. Inst. Min. Engrs., Trans. XXII: 171, 1894.
32. Siebenthal, Econ. Geol., I: 119, 1906.
33.
(Genesis.)
(Joplin.)
Siebenthal, U. S. Geol. Surv., Bull. 606, 1916.
(Origin Joplin ores.)
34. Smith and Siebenthal, U. S. Geol. Atlas Folio, No. 148, 1907.
(Jop-
Surv.,
Eng. and Min. Jour., LXXVII: 517, 1904. (Rel'n

36. Winslow, Mo. Geol. Surv., VI and VII,
1894.
(Mo. and general.) Montana: 37. Pepperberg, U. S. Geol. Surv.
Bull. 430: 135, 1910.
(Bearpaw Mtns.) Nevada: 38. Bain, U. S.
New Jersey: 39. Kemp, N. Y. Acad.
Geol. Surv., Bull. 285.
(Zinc.)
40. Spencer, N. J. Geol. Surv., Ann. Rept..
Sci., Trans. XIII: 76, 1894.
1908: 23, 1909. 41. Wolff, U. S. Geol. Surv., Bull. 213: 214, 1903,
New Mexico: 42. Lindgren, Graton and Gordon, U. S. Geol. Surv..
lin.)
35. Wheeler,
lead to
igneous
rock.)
Prof. Pap. 68, 1910.
(Tres
Hermanas
(General.)
district.)
New
43. Lindgren. Ibid., Bull. 380, 1908,

44. Ihlseng, Eng. and Min.
York:
LXXXV:
45. Newland, N. Y. State

(Ellenville.)
630, 1903.
Oklahoma:
Bull. 161: 101, 1912.
(St. Lawrence County.)
47. Snider, Okla.
46. Siebenthal, U. S. Geol. Surv., Bull. 340, 1907.
Jour.,
Museum,
Geol. Surv., Bull. 9, 1912. Pennsylvania: 48. Clerc, U. S. Geol. Surv.,

Min. Res., 1882: 61. 49. Hall, Sec. Pa. Geol. Surv., D3: 239. Tennes51. Osgood,
see: 50, Keith, U. S. Geol. Surv., Bull. 225: 208, 1904.
Tenn. Geol. Surv., Bull. 2, 1910. 52. Purdue, Tenn. Geol. Surv., Bull.
53. Watson, Amer. Inst. Min. Engrs., Trans.
14, 1912.
(N. E. Tenn.)
XXXVI: 681, 1906. United States: 54. Ingalls, Lead and Zinc in
55. U. S. Geol.
the United States. New York, 1908.
(Historic.)
Statistics and trade
Surv., Mineral Resources, published annually.
data. Utah: 56. Crane, Amer. Inst, Min. Engrs., Bull. 106: 2147,1915.
57. Tower and Smith, U. S. Geol. Surv., 19th Ann. Rept., Ill:
(Tintic.)
LEAD AND ZINC

601, 1899.
(Tintic.
657
District as a whole treated under Lead-Silver ores.)
58. Zalinski, Eng. and Min. Jour., June 21, 1913.

(Tintic ox'd zinc ores.)
Virginia: 59. Watson, Va. Geol. Surv., Bull. 1, 1905; also Min. Res.
Va., 1907. 60. Watson, Amer. Inst. Min. Engrs., Trans., XXXVII:
304, 1907.
(Metallurgy, etc.) Washington: 61. Bancroft, U. S. Geol.
(Metaline district.) Wisconsin: 62. ChamberSurv., Bull. 470, 1910.
Geol. of Wis., Pt. IV, 1882. 63. Grant, Wis. Geol. and Nat. Hist.
Surv., Bull. 14, 1906. 64. Wright, C. A., Bur. Mines, Tech. Pap. 95.
(Mining and milling.) Canada: See refeiences under Silver-Lead ores.
lin,
CHAPTER
XVIII
SILVER-LEAD ORES
THE
form a large class, of rather wide distwo metals characterizing the group are
and
while
the
tribution,
also
there
be, and often is, present a variable
prominent,
may
of
as gold, zinc, and copper. Indeed,
other
metals
such
quantity
some that are included in this chapter might possibly be placed
in the fallowing one.
The silver contents, though sometimes
are
not
high,
necessarily visible, and may be contained within
silver-lead ores
the galena as Ag2S. 1

The ore bodies as a whole present a variety of forms, the
ore having been deposited either by cavity filling or replacement, or both. Most of the important occurrences seem to
have been formed at intermediate depths. Oxidation zones
frequently cap the ore body, and downward secondary enrichment has probably occurred in some cases.
Silver-lead ores
form a widely distributed
class in the
Cor-
dilleran region of the United States and supply most of the

lead mined in this country.
Deposits are prominent in Colo-
rado, Idaho, and Utah, but are also
known
in
New
Mexico,
Montana, Wyoming, Nevada, Arizona, California, and South

Dakota.
Canada supplies a small but steady production from British
Columbia, while in other foreign countries districts worth
noting for either commercial or historic importance are Broken
Clausthal and Freiberg, Germany;
Hill, New South Wales;
Przibram, Bohemia; Sala, Sweden; Laurium, Greece; Mexico,
etc.
Deep-vein Zone Deposits

United States.
Silver-lead mines of this class are
unim-
portant in the United States, but some carrying tourmaline

occur in the Boulder batholith (15) of Montana (p. 593).
1
Xisscn, A. E., and Hoyt, S. L., Ecoii. Geol.,
658
X:
172, 1915.
SILVER-LEAD ORES
659
In Canada there are certainly two occurrences

Columbia that should be mentioned. One of these,
the Sullivan mine (30), northwest of Cranbrook, represents
Canada.
in British
a conformable replacement of argillaceous quartzites by galena,

blende, iron sulphides, and jamesonite (Pb2Sb2i$5), with garnet,
This has been a good prodiopside, actinolite, and biotite.
ducer.
The other deposit, no longer worked,

at Moyie (29), which is a replacement in a
is
the St. Eugene
fractured quartzite,
similar
mineral
somewhat
shows
and
composition to the preceding.
The best-known example perhaps of this
Other foreign deposits.
1
group is the Broken Hill Lode in western New South Wales.
This great lode, discovered in 1883, was first worked for silver, then
The rocks of the region include:
silver lead, and in recent years, also zinc.
(1) pre-Cambrian sediments, chiefly arkoses and sandstones near the lode,
all altered to gneisses and schists; (2) amphibolites derived from eruptives;
and (3) granite gneisses and pegmatites. Regional metamorphism was
accompanied by shearing along the line of the lode, and later injection of
pegmatite along the ore zone. There was also developed in the country
rock, garnet, gahnite (ZnAl 2 O 4 ), sillimanite, and rhodonite.
The ore bodies, which are associated with the shear zone, often form
A gossan rich in manganese and iron,
peculiar saddle-shaped masses.
passes downwards into oxidized ores of lead, silver, and some copper, while
below this is a coarse-grained mixture of sphalerite and galena, carrying
Oxisilver, and intergrown with quartz, garnet, feldspar, and rhodonite.
dation extends to depths of 500 to 600 feet, and secondary enrichment is
The primary ores average 3 to 14 oz. silver, 14 to 16 per
well marked.
cent lead, and 8 to 18 per cent zinc.
The theories advanced to explain these saddle deposits include, lateral
secretion (Pittman and Jacquet); bedded deposits (Krusch, Stelzner and
Bergeat); epigenetic origin (Beck), and contact metamorphism (Vogt).
Moore 2 suggests replacement in the hanging wall of the tabular shear zone,
the beds being replaced in such a way as to give the saddle form.
In this same group may also be mentioned the lead-silver-zinc ores of
Sala,
Sweden, which occur in dolomitized limestone.
One
series of steeply-
dipping ore bodies carries silver and lead, with some blende, pyrite, arsenopyrite, and stibnite; the other series of lesser dip predominates in zinc.
The
ore minerals are intergrown with salite, tremolite, actinolite, epidote,

and a little tourmaline. They are regarded as replacements, but
biotite,
show no
direct connection with
any
instrusive. 3
Vogt, Krusch, and Beyschlag, Ore Deposits, Translation, I: 399, 1914.

Jacquet, Mem. Geol. Surv., N. S. W., No. 5 Geology, 1894; Mawson, Mem.
Roy. Soc. S. Austral., 1912; Austral. Inst. Min. Engrs., VI, No. 2, 17, 1910.
1
Manuscript notes, kindly loaned to author

Vogt, Krusch, and Beyschlag, Lagerstatten, II: 264, 1912; also Sjogren,'
Internat. Geo!. Cong., Stockholm, 1910, Guidebook, No. 28.
3
ECONOMIC GEOLOGY
660
Deposits Formed at Intermediate Depths
United States.
Most of the occurrences of silver-lead ores
found in the United States are placed in this group.
The Cceur d'Alene district
Coeur d'Alene, Idaho (13).
(which
120
120=
is
really
116
ll'J=
118-
119
FIG. 229.
made up
Map
116-
117
117
of
several local
114
115"
113
mining
112 3
112
11
showing location of Coeur d'Alene,

some, U. S. Geol. Sun., Prof. Pap.
districts)
111-
110"'
111
Ido., district.
(After
Ran-
62.)
Shoshone County, mostly on the western slope of the

Cceur d'Alene Mountains. Wallace is the principal town,
but there are several smaller ones, as Wardner, Mullan, Burke,
lies in
Mace, Gem, and Murray.
The
prevailing rocks here are a thick (10,000 feet), apparently

conformable series of shales, sandstones, and some limestones of
Algonkian age, which on the west are faulted down against granitic
and gneissic rocks, but extend some distance to the eastward.
The condensed
section
is
as follows:
FEET
and sandstones
Wallace sandstones, shales and limestones
St. Regis shales, and sandstones
4,000
Revett white quartzite
1,200
Striped
Peak
shales
shales and sandstones

Prichard shales and sandstones
Burke
....
1,000
1,000+
2,000
8,000
17,200
FIG.
1.
View near Linden
in
Wisconsin lead and zinc
district.
(H.
Ries,
photo.)
2.
View looking north over the Coeur d'Alene Mountains from the Stemwinder tunnel above Wardner. Shows mature dissection of plateau-like uplift.
Town of Wardner in foreground. (After Ransome, U. S. Geol. Sure., Prof. Pap.
FIG.
62.)
(661)
ECONOMIC GEOLOGY
662
The igneous rocks includes some small intrusive stocks of monzonite, and a few dikes of diabase and lamprophy re-like rocks,
but the age of
Areas
in
which
uncertain.
all is
Areas in which occur
occur lead-silver
lead-silver deposits of
deposits of
secondary Importance
known primary
po far at present
FIG. 230.
Geologic
map
of
which
copper
.n
Principal a
area
Prospects or mines
Dot of primary"
importance
Coaur d'Alene, Ido., district.

Pap. 62.)
(After
Ransome, U. S.
Geol. Surv., Prof.
The rocks show a
series of complex,
sometimes overturned,
been
folds as well as extensive faults, and slaty cleavage has

developed in all except the quartzite.
to
The largest ore bodies, although wonderfully persistent, are likely

become poor at depths ranging from 1000 to 2000 feet. Three
types of ore bodies are recognized, and of these, which are described
below, the first is the most important.
deposits, consisting essentially of metasomatic
formed in greater part by replacement of siliceous
sedimentary rocks, along zones of fissuring, and carrying mainly
galena and siderite. The galena may first replace the quartzite, or
siderite may replace quartzite first and then be replaced by galena.
Pyrite and sphalerite are always present, and tetrahedrite, if
1.
Lead-silver
fissure veins,
SILVER-LEAD ORES
663
found, indicates high silver values, but chalcopyrite

dized ores occur above.
The
lead-silver
veins,
which
is
rare,
Oxi-
in that portion drained
by
and its tributaries, occur
mostly in the Burke formation, while
a few are found in the Revett, Wallace, St. Regis, and Prichard.
The average contents of ore in silver
is a little over half an ounce to each
lie
mainly
the south forks of the Coaur d'Alene River
per cent of lead per ton.
Bunker
In 1914 the
and Sullivan milling ore

10.35 per cent of lead and
Hill
assayed
3.796 ounces silver, while concentrates
from the same mine averaged 62.91 per
FIG. 231.
Section of lead-silver vein,
Coeur d'Alene, Ido. (1) Country

rock. (2) Sheared rock.
(3) Galena and siderite. (4) Fissure with
fine-grained galena.
(5)
Barren,
country rock.
{After
Finlay Amer. Inst. Min. Engrs.,
silicified
cent lead and 20.68 ounces silver. The

tailings assayed 2.675 per cent lead and
The bulk of
1.331 ounces of silver.
the ore ranges from 3 to 14 per cent
lead and 2.5 to 6 ounces silver per
Most of the ore in the district
ton.
is
XXXIII.)
concentrated to 50 or 60 per cent
lead.
and concentrates may be sent to Tacoma San Francisco

Helena, Montana; etc.
In the mines, the galena is shown to have a vertical range of at least
The
rich ores
Salida, Colorado
2600
feet.
2.
Gold deposits, including bed veins,

two periods.
fissure veins,
and
placers formed
in at least
The productive gold-quartz
veins occur near
Murray and
are bed
following stratification planes of the Prichard formation.

They
are usually a foot or two in width and carry quartz, gold, pyrite, galena,
The
sphalerite, and chalcopyrite, with occasional bunches of scheelite.
veins,
average value of the ore probably does not exceed over $7 per ton.
3. Copper deposits, consisting either of impregnations along certain
quartzitic beds or metasomatic fissure veins.
Only the former type is of
commercial importance, and at the Snowstorm mine it forms an imThe ore is chalcopyrite,
pregnated zone with a maximum width of 40 feet.
bornite, chalcocite, etc., and the greater part runs 3 to 4 per cent copper,
and 4.5 to 5.5 ounces silver.
It is believed that the association of
Origin of lead-silver ores.
the ore with fissures and the absence of irregular deposits indicate
has been deposited by ascending solutions, moreover the

mineralogical composition of the ore suggests its precipitation from
hot solutions.
that
it
These solutions are thought to have been given

zonite in vaporous form, producing contact
by the monmetamorphism and

off
ECONOMIC GEOLOGY
664
depositing ores rich in sphalerite and pyrrhotite associated with

garnet and biotite, found in some parts of the district.
Farther away from' the intrusive the lead-silver ores were deposIt is probable that the solutions entered the stratified rocks
carrying ferrous carbonate and lead sulphide, and not only filled the
open spaces but replaced the quartzite.
ited.
The first prospecting occurred in this district about 1878, and subsequent discoveries in 1879 started a rush to this region, but this centered
round the placers, which commanded the most attention even up to 1885
but in the following year the miners awoke to an appreciation of the leadsilver deposits, and the building of a railroad into the district in 1887 gave
a great impetus to the lode-mining industry. Since then the Cceur d'Alene
has been an important producer, in spite of severe though temporary setbacks due to labor troubles in 1892 and 1899.
;
Park
City,
Utah
(22),
which
is
located on the eastern slope
Wasatch Range, about 25 miles southeast of

City (Fig. 246), has made Summit County famous
of the
Salt
Lake
as one of
the important mining centers of this country, as there are here

large bodies of rich silver-lead ores carrying minor values of
gold and copper. The success of this camp, therefore, depends
more or less on the condition of the silver and copper industry.

The geological section involves a series of limestones, quartzites, and shales, of Carboniferous to Triassic age, the series
being folded into an anticline, which has been intruded by
diorite rocks of post-Cretaceous age.
The
Numerous
fault fractures
which in the oxidized zone are

cerussite, anglesite, azurite, malachite, etc., and in the sulphide
zone are galena, sphalerite, tetrahedrite, and chalcopyrite,
occur either as lodes or fissures, or as bedded deposits in limestones.
The latter, which supply most of the ore, form replacements in certain strata of both the Upper Carboniferous
and Permocarboniferous, and lie between siliceous members
cross the district.
as walls.
Both types
ores,
of ore deposit are frequently associated
with porphyry.
The
fissures carry either silver or lead
with or without zinc,
and copper or gold with some silver. The replacement ores of

the limestones hold silver and lead chiefly. The contact ores
contain copper and gold \vith or without silver, and form
irregular
bodies
igneous rock.
in
metamorphic limestone adjacent to the
SILVER-LEAD ORES
FIG. 232.
Map
of
Nevada, showing location
The ordinary crude
of
more important mining
665
districts.
ore carries 50 to 55 ounces silver, 20 per cent lead,

Silver is
ounce gold, 1.5 per cent copper, 10 to 18 per cent zinc.
obtained in the proportion of 3 ounces silver to each per cent iron, 1 ounce
.04 to .05
ECONOMIC GEOLOGY
666
silver to
each per cent lead, and .5 ounce silver to each per cent zinc.
The low-grade ores are treated at the concentrat-
Bonanzas are known.
ing mill, while the rich ores are shipped to the smelter.
Tintic
District,
Utah
(23
and
26)
This district
lies in
the
Tintic Mountains, about 65 miles southwest of Salt Lake City

The rocks of the district include over 12,000 feet
(Fig. 246).
of
Paleozoic
sediments,
and broken by
folded into an
faulting,
fissuring
overturned syncline,
Following a
and sheeting.
period of erosion there was a period of igneous activity in the
IIIWMI
Qtsartztte
ff/?yo//te
KflKdHliU
Eureka
Gnrfivn /
antA
imp
K"^^! Monzonite
Ww&A
fiumt>ug\
Series I
/V/uvit.
MINES
FIG. 233.
Geologic
map of Tintic district,
Utah.
MINEULS.
(Adapted from Tower and Smith.)
Tertiary, yielding rhyolites, tuffs and breccias, as well as monThe ore deposits include: (1) Thin ironzonitic intrusions.
manganese deposits on the limestone-igneous rock contacts;
(2)
and
veins of silver-lead ores in monzonite, mostly abandoned;

The last, or most
(3) limestone replacement deposits.
important, occur in four parallel zones, the lead-silver ores

predominating at the north end of the belts, and gold-copper
ores at the south end, while zinc is found in both.
The ores
are mainly oxidized ones, weathering having reached a depth
from 1500 to 2300 feet. Crane suggests that the ore-bearing

solutions came from the monzonite.
The Tintic is one of the oldest camps in the state, the ore
of
PLATE LXII
FIG.
1.
General view of Rico, Col., and Enterprise group of mines.
FIG.
2.
\icw
of a portion 01 Aieix-ui, I tan,
and the Mereur mine.

(667)
ECONOMIC GEOLOGY
668
having been discovered in 1869, and it was at first shipped as

far as Baltimore and Wales.
Since then mills have been erected
at the mines.
The chief towns are Eureka, Mammoth, Rob-
and Diamond.
The same type of ore occurs in Big and
canons .and Bingham Canon (Fig. 246), the
inson, Silver City,
Little
Cottonwood
latter
having been
worked longer than those of the Tintic district. The camps

lie southeast and southwest of Salt Lake City, and the ores
are oxidized silver-lead ones, parallel to the bedding of Carboniferous limestones and the underlying quartzite. Galena
and pyrite occur in the lower workings below water level.

San Francisco district, Utah (23).
This is an area producing essentially silver-lead ores, as well as copper and zinc,
and lies in Beaver County, Utah. There is a sedimentary
series of Paleozoic limestones, shales, and quartzites, covered
by a thick flow of lava, and intruded by quartz monzonite and
related rocks.
The
ore
deposits consist of:
(1)
Replacements
along fissures in quartz monzonite, as in the Cactus ore zone,

referred to under Copper; (2) replacements in limestone, con-
with smaller amounts of gold and

copper, and also some contact deposits; (3) replacement fissure
deposits in the lava, the primary ore containing chiefly pyrite,
sisting chiefly of lead-silver
galena,
lava.
and sphalerite
in a
gangue
Interesting replacements of
Aspen,
Colorado
(ll).
The
of quartz, sericite
and altered
one sulphide by another occur.
ores are oxidized
and occur
in
highly folded and faulted Carboniferous limestone, although the

section involves rocks ranging in age from Archa3an to Mesozoic.
Two quartz porphyries, one at the base of the Devonian, the other
in the Carboniferous, are present, but bear
no special relation to the
ore.
At the
close of the Cretaceous the rocks
were folded into a great
anticline, with a syncline on its eastern limit, which passed into a

Contemporaneous
great fault along Castle Creek west of the mines.
with the folding there were also produced two faults parallel to the
bedding of the Carboniferous dolomite, while at the same time much

The ore is found chiefly at the intersection
cross faulting occurred.
of these two sets of fault planes, and Spurr believes that the ores
were deposited by magmatic waters ascending vertically along
faults, and were precipitated by a reaction between the solutions
and certain wall rocks, chiefly shale. Mingling of solutions at
SILVER-LEAD ORES
669
the intersection of fissures also played an important role in the

formation of the ore. This stronger deposition of the ore at the
was thought by Weed to be due to

but
Spurr finds little evidence of secondary
secondary enrichment,
intersection of fault planes
sulphide formation.
On account of the intimate association of the dolomite, quartz, and
barite with the ore their origin is considered as similar.
The
ores
are
peculiarly
from other metals except

lead and the rich polybasite
free
(AggSbSe) ores of Smuggler

Mountain do not contain
even
this.
The mining camp of Aspen

started in 1879, but
velopment
its
de-
a time was
for
much retarded by lawsuits.

The richer ore bodies were
not discovered
until
1884,
and then by underground

exploration, for owing to the
heavy mantle of glacial gravden.
outcrops were hidSince also the ore
carries
no iron or manganese,
els their
as do the Leadville ores, its
outcrop
be inconspic-
may
uous.
I
'--
PARTING QUARTZITE
The railroads did not reach

camp until 1887, so that
the
YULE FORMATION
WEBER FORMATION
LEADVILLE DOLOMITE
during the
SAWATCH FORMATION
I****
first
history the ore

out on burros.
** GRANITE
QUARTZ PORPHYRY
FIG. 234.
Section of ore body at Aspen, Col.

(After Spurr, U. S. Geol. Surv., Man. XXXI.)
few years of its

to be carried
had
In both Aspen and Smuggler

Mountains long tunnels have
been run for drainage and hauling purposes.
The Cowenhoven
over 8300 feet long, and taps a

number of mines. Aspen was one of the first mining camps in the West
to install electric machinery for hoisting, haulage, etc., and the current
was cheaply supplied by the neighboring water power. One shaft 1000
tunnel, which
feet
is
the largest of these,
is
deep
At
is operated electrically.
the present day the larger ore bodies are worked out, but the
camp
ECONOMIC GEOLOGY
670
From
still an active producer.

worth of silver.
is
1881 to 1895
it
produced $63,653,989
In this region the

Rico, Dolores County, Colorado (3, 9, 10).
of
which
are
the
remains
the
structural
dome rising
mountains,
above the Dolores plateau lying
in the
San Juan
region, contain
sedimentary beds ranging from Algonkian to Jurassic in age,

which have been uplifted partly
series of
by the intrusion of igneous rocks,

as stocks, sills, and dikes, and
by upthrows due to fault-
partly
ing.
The
ore occurs as lodes, re-
placements in limestones, stocks,

and blankets, the last consisting
usually of
deposits
parallel to the planes of
lying
bedding
or to the sheets of igneous rock,

and known locally as " contacts." although not such in the
true sense.
The four types of deposit mentioned
Most
has,
may pass into each
other.
of the ore in the district
however, come from the

and the bulk of this
blankets,
has been found in the Carbon-
FIG. 235.
Diagrammatic section across
a northeasterly lode at Rico, Col., show"

"
l
an ke * of r e
? i
,
,
L S. Geol.j Surv., 22d
Ann.
Rept.)
:
iferous,
mosa
especially
in the
W^*;~.
Her-
formation, a striking feature of the deposits being their limited
vertical range.
The ores are primarily galena, often highly argentiferous and

associated with rich silver-bearing minerals.
In many deposits
the more or less complete oxidation of the silver ores has resulted
in
powdery masses, often very
rich in silver.
Below the zone
of
oxidation, the veins have not been successfully worked.

The bulk of the ores can be roughly divided into j>yritic ores,
usually low grade, and silver-bearing galena ores, sometimes con-
taining rich silver minerals.

Quartz is the commonest gangue mineral, but the beautiful pink rhodochrosite is also conspicuous.
The
ore deposition is believed to be closely associated with the

igneous intrusions of the district, especially with the later ones.
SILVER-LEAD ORES
671
Most of the ore produced in the Rico district has been shipped
crude or smelted in Rico without mechanical concentration.
Other Occurrences.
district
in Chaff ee
(4),
Argentiferous lead ores also occur in the Ten Mile

County, and along the Eagle River (8), both in
Colorado.
The Eureka
in 1868,
is
district
(17,
18)
of eastern
chiefly of historic importance.
Nevada (Fig. 232), discovered

The ores are oxidized lead-silver
some gold. They occur

Cambrian limestone which is much
faulted and crushed, and is part of a
ores, carrying
in
Paleozoic section 30,000 feet thick.

The ore is associated with a great
and
oxidized to a depth of
There are two mining districts, Prospect Hill and Ruby Hill.
Near the mines are great prophyry
masses which are supposed to have
afforded the ores.
Up to 1882 the
output was not far from $60,000,000
of precious metals and 225,000 tons of
lead, but the production now is insigfault,
1000
is
feet.
nificant.
Montana
contains
lead-silver ore localities.
of Neihart
(16)
several
Those
occur as veins
gneiss and igneous rocks,

the ores being galena, silver sul-
Wt;
in
phides, and some blende.

veins are best defined in
The
Sandstoce
the FlG 236
gneiss, and are mostly replacement deposits, which have been

and
fractured
subsequently
Crushed Rock
|4r-s
Shodochrosi t e
Vein
Trans,
filling
a fault
f^M.
fissure,
Zt
xxvi.)
secondarily enriched. Lead-silver ores also occur at Glendale

and in Jefferson County. Some are also known in South
Dakota, and at Lake Valley, New Mexico (20, 21).

Canada. British Columbia.
The Slocan (28) district, which
lies between the Kootenay and Arrow Lakes of the Selkirk
province of southern British Columbia, contains a number of
and zinc deposits. The country rock includes a
series of interbedded argillaceous quartzites, limestones and
silver-lead
slates of the Slocan series (Carboniferous ?) which have been

invaded by the granitic rocks of the Nelson (Jurassic ?) bath,
olith.
Folding, faulting, and lithologic similarity of the sedi-
ECONOMIC GEOLOGY
672
merits have interfered with an
accurate determination of the
an extensive system of quartz

porphyry and lamprophyre dikes which seem to antedate the
There
structural details.
The
vein fissures.
is
also
ores occur in veins, in part breccia
filled,
whose length varies from a few hundred to over 4000 feet,

and a thickness of from a few inches to over 50 feet. Ore
shoots of varying size and sometimes following cross-fractures
are common. The chief ore minerals are galena, sphalerite
and freibergite, as well as ruby silver, native silver, and argentite.
Chalcopyrite and pyrite are common but unimportant. Siderite, calcite, and quartz form the gangue.
Weathering effects
are shallow, and the ore seems to be primary, derived probably
from the Nelson batholith.
The tenor of the ores ranges from 7 per cent Pb and 20
ounces per ton Ag to 50-75 per cent Pb and 80-175 ounces
per ton Ag.
little
gold
is
found in some.
Other foreign deposits.

Przibram, Bohemia, is a classic locality,
1
The steeply dipping veins occur in grayyielding argentiferous lead ores.
slates, which have been folded, faulted, and intruded by
a diorite stock. There are also a number of diabase dikes, which follow
the veins more or less closely. The veins, some of which have been followed to a depth of over 3500 feet, show a variable thickness, some being
wackes and clay
feet.
The common ore minerals are galena and blende, with some
pyrite and chalcopyrite, in a gangue chiefly of calcite, siderite, and quartz.
Silver sulphides are found especially in the oxidized zone.
Where the veins
pass from the graywacke into the diorite, they may lose their galena and
25
and take up stibnite (Plate XLI, Fig. 1). The origin is not perfectly
but was possibly connected with the associated intrusives.
The Freiberg, Saxony, district, now practically closed, possesses an
historic interest, because it was here that Werner in 1791 developed his
theories regarding fissure veins. The veins, of which over 1100 are known,
occur in an arch of biotite gneiss, and are separable into an older and a
silver,
clear,
younger group.
The former
and argentiferous ("noble
'')
contains the argentiferous quartz, pyritic lead,

lead formation.
The latter, the barytic-lead
formation. 2
r
3
Clausthal, Germany, is also w ell known on account of its series of veins
carrying argentiferous galena, blende, and subordinate chalcopyrite, pyrite,
or marcasite, in a gangue of calcite-quartz (Plate XL), or barite-siderite.
The enclosing formations consists of Devonian and Carboniferous clay
and graywackes. The ores are found filling fissures or breccia zones,
and while unassociated with igneous rocks, may be genetically connected
with the granite of the Brocken Mountains of the Harz.
slates
und Beyschlag, Lagerstatten,
Vogt, Krusch,
Ibid., II:
163, 1912.
Ibid., II:
177, 1912.
II: 197, 1912.
SILVER-LEAD ORES
is another locality deserving mention, its

replaceof ores carrying argentiferous galena and sphalerite in crys-
Laurium, Greece,
ment deposits
talline limestone.
as a
673
Bawdwin mines are looked upon by some

They represent replacements of ancient vol-
In Burma,- the
coming great producer.
canic rocks. 2
Among
the Mexican silver-lead deposits those of the
Sierra
Mojada
forming replacement deposits in Cretaceous limestone and similar ones

of the Santa Eulalia district 4 are of importance.
Deposits Formed at Shallow Depths
United States.
In the Creede
district
lead-silver zinc veins occur in rhyolite,
Colorado
of
and rhyolite
the ore carrying sphalerite, galena, pyrite,
etc.,
(5),
breccias,
in a
gangue
of manganiferous quartz, barite, chlorite, and adularia.

At Lake City, Colo. (6), the ores fill fissures in Tertiary
The primary
flows and tuffs of the Silverton volcanic series.
minerals at lower levels are chiefly quartz, galena, blende, and

pyrite, while at shallower depths there are also tetrahedrite,
rhodochrosite, barite, and jasperoid. Secondary minerals are
chiefly pyrargyrite and galena, as well as some chalcocite and
Native gold occurs in the upper part of

possibly proustite.
the sulphide enrichment zone. The mineralizing solutions came
probably from a quartz-monzonite intrusion.
REFERENCES ON SILVER-LEAD
Knopf, U. S. Geol. Surv., Bull. 580-A: 1, 1914. (Darwin
Colorado
3.
Spurr, U. S. Geol. Surv., Bull. 208, 1903.
Cross and Spencer, U. S. Geol. Surv., 21st Ann. Rept., II: 15, 1900.
(Rico Mts.). 4. Emmons, S. F., Ibid., Ten Mile Atlas Folio.
(Ten
Mile district.) 5. Emmons, W. H., and Larsen, Ibid., Bull. 530: 42,
California:
1.
dist.).
2.
1913.
(Creede.)
6.
Irving
and
Bancroft,
Ibid.,
Bull.
478,
1911.
XVI: 570,
(Lake City.) 7. Kedzie, Amer. Inst. Min. Engrs., Tran
1888.
(Red Mts.) 8. Olcott, Eng. and Min. Jour., XLIII: 418,
9. Ransome,
(Eagle Co., Colo.)
436, 1887 and LIII: 545, 1892.
10.
U. S. Geol. Surv., 22d Ann. Rept., II: 229, 1902.
(Rico Mts.)
Rickard, Amer. Inst. Min. Engrs., Trans. XXV: 906, 1896.
(Enterprise
Mine, Rico.) 11. Spurr, U. S. Geol. Surv., Mon. XXXI, 1898; also
Econ. Geol., IV: 301, 1909. (Aspen.)
Idaho: 12. Hershey, Min.
and Sci. Press, CIV: 750, 786 and 825, 1912. (Wardner district.)
1
Vogt, Krush und Beyschlag, Lagerstatten, II: 163, 1912.
Hoffman, Min. Mag., XIV: 39, 1916.

Malcolmson, Amer. Inst. Min. Engrs., Trans. XXXII: 100, 1902.
*
Weed, Amer. Inst. Min. Engrs., Trans. XXXII: 396, 1902.
ECONOMIC GEOLOGY
674
13.
Ransome and
(Cocnir d'Alene.)
Montana:
15.
lead veins.)
16.
1900.
(Neihart.)
Calkins, U. S.
14.
Umpleby,
Geol. Surv., Prof. Pap. 62, 1908.

1914.
(Dome dist.)
Ibid., Bull. 540,
Knopf, Econ. Geol., VIII:
105, 1913.
(Tourmaline
Weed, U. S. Geol. Surv., 20th Ann. Kept., Ill: 271,

Nevada: 17. Curtis, U. S. Geol. Surv., Mon. VII,
1884.
18. Hague, Ibid., Mon. XX, 1892.
19.
(Eureka.)
(Eureka.)
New
(Pioche.)
Pack, Sch. M. Quart., XXVII: 285 and 365, 1910.
Mexico: 20. Clark, Amer. Inst. Min. Engrs., Trans. XXIV: 138.
(Lake Valley.) 21. Lindgren, Graton and Gordon, U. S. Geol. Surv.,

Prof. Pap. 68, 1910.
Utah
22. Boutwell, U. S. Geol. Surv., Prof.
Pap. 77, 1912. (Park City.) 23. Butler, U. S. Geol. Surv., Prof.
Pap. 80, 1913, also Econ. Geol. IX: 413, 1915. (San Francisco.) 23a.
:
(Tintic.)
Crane, Amer. Inst. Min. Engrs., Bull. 106: 2147, 1915.
Econ. Geol., X: 225, 1915. (Mineral'n and enrich't,
24. Lindgren,
Econ. Geol., IX: 1, 1914. (Oxid. zinc ores,

Ann. Kept,, III: 601, 1899.
27. Argalls and others, Rept. of Com. on Zinc
Tintic.)
25. Loughlin,
Tintic.)
26.
Tower and Smith, 19th
(Tintic.)
Canada:
Resources
Brit.
Col.,
Mines
Branch,
1906.
28.
LeRoy,
Internat.
29. Schofield,
(Slocan.)
Congr., Canada, 1913, Guidebook 9.
Can. Geol. Surv., Summ. Rept. for 1911: 158, 1912.
(St. Eugene
30. Schofield, Econ. Geol., VII: 351, 1912.
(E. Koomine, Moyie.)
Geol.
tenay, Brit. Col.)

British Columbia.
31. See also
annual reports of Minister of Mines,
CHAPTER XIX
GOLD AND SILVER
GOLD and silver are obtained from a variety of ores, in some of
which the gold predominates, in others silver, while in still a third
class these two metals may be mixed with the baser metals, lead,
copper, zinc, and iron. Few gold ores are absolutely free from silver,
and vice versa, so that a separate treatment of the two is more or less
however, some lead-silver
difficult;
ores,
although they
may
carry
some
gold, are sufficiently prominent to be discussed as a separate

and
have been referred to in the preceding chapter.
type,
Ore Minerals of Gold.
Gold occurs in nature chiefly as native
mixed with pyrite, or as telluride such as calavAu, 39.5 per cent; Ag, 3.1 per cent; Te, 57.4 per
gold, mechanically
erite
cent).
(AuTe2
Gold
stibnite,
pyrite.
is
also
found at times in chalcopyrite, arsenopyrite, and
but not as a rule in such large amounts as may be shown by

Sphalerite and pyrrhotite sometimes carry it.
The gold-bearing
sulphides, as well as the tellurides, are of
primary character, although auriferous chalcopyrite might be

formed by secondary enrichment.
Native gold may occur in the primary, secondary enrichment,
or oxidized zones.
The tellurides, which are usually associated
with pyrite, are widely distributed, though not so abundant,
but not always recognized; indeed by some they are mistaken
for sulphides.
Ore Minerals
of Silver.
The minerals which may
serve as
ores of silver, together with the percentage of silver they contain, are shown in the table on the following page.
Galena, sphalerite, pyrite, chalcopyrite, and chalcocite
may
all
be and frequently are argentiferous, but in most ore deposits

is usually favors the first named.
Of the ore minerals above mentioned, the most common primary
ones are argentiferous galena, sphalerite, and pyrite, while native
silver and the sulphides and arsenides are less common.
1
Other tellurides are sylvanite and krennerite.

675
ECONOMIC GEOLOGY
676
MINERAL
GOLD AND SILVER

ment has been
much
active.
On the
677
other hand the influence of locality
has been found that
many gold- and

deposits are closely associated with masses of
igneous rock, the most common of these being diorite, monzonite,
quartz-monzonite, granodiorite, while true granites are rare as
is
stronger, for
it
silver-bearing
A second large class of vein systems shows a close

with
lavas of recent age, and the telluride ores rather
association
associates.
favor these
(s).
The superficial alWeathering and Secondary Enrichment.

from
ores
differs
somewhat
of
that of deposits
teration
gold
containing ores of the other metals. In quartz veins with auriferous pyrite, the change of the latter to limonite leaves a rusty
quartz with nuggets or threads of free gold, and leaching may
remove most
of the iron.
The
conditions under which gold is

of manganese are discussed on p. 480.
Telluride ores weather in a
removed by the influence
somewhat
characteristic manner,
the product being free gold. This may be of earthy appearance

and faint brownish color, or consists of aggregates of extremely
small crystals of gold which form a spongy mass, or a thin film
on the surface of the rock.

Silver sulphides are changed to chlorides, and native silver
may also be formed. In the weathered portion of some silver-
bearing deposits, silver bromides and iodides are also fcund.

Penrose has suggested l that such ore bodies were in the
vicinity of saline deposits,
where haloid compounds were
dis-
waters that penetrate the ores. Keyes, howbelieves

that
the prevailing source of saline materials is
ever,
the wind-blown dust produced by disintegrative processes so
solved
by the
predominant
soil
in arid regions (9).
Downward secondary enrichment has
evidently occurred in
a number of silver and silver-gold deposits.

According to
W. H. Emmons (7), all deposits in which gold appears to have
migrated include manganiferous ores. In deposits carrying both
metals, especially where chlorides form, secondary silver minerals are likely to be precipitated as bonanzas near the surface,
while gold is carried deeper, but if chlorides are not formed in
manganiferous deposits, silver may be carried deeper than gold.
is said to rapidly halt the downward migration of both gold and silver. In copper deposits where silver
Uour. Geol. II: 1894.
Abundant pyrrhotite
ECONOMIC GEOLOGY
678
and gold migrate downward, these are deposited chiefly in the

upper part of the secondary sulphide zone. Many deposits
of rich silver ore and some of rich gold ore terminate down-
ward
in low-grade sphalerite ores.
Geological
Gold and
Distribution.
deposited at a
number
silver
have
ores
been
periods in the geological

history of the continent, notably, in the pre-Cambrian, Camof
different
brian, Cretaceous, and Tertiary ages.

Some of the Appalachian veins are probably early Paleozoic,
and those of Nova Scotia are post-Cambrian. Silver ores show
much
The
the same geological range.

geological distribution is referred to in
more
detail
under
Metallogenetic Epochs in Chapter XIV.
A classification of gold and silver ores is in

Classification.
any event attended with mere or less difficulty. Divisions
based on geological and structural characters would for many
purposes be more satisfactory, while for commercial or metallurgical work a grouping according to metallic contents is perhaps more desirable.
The following classification according to the associations of
the ores is sometimes used in the United States.
1.
These serve
Placers or Gravel Deposits.
chiefly as a source
of native gold, but may, and often do, contain a little silver,
mucn of which is never separated from the ore in which it occurs.
from quartz veins of Mesozoic

and to a less extent from preCambrian veins of the Appalachian region and Black Hills
of South Dakota.
Some are also derived from veins in Tertiary
These gravels are derived
chiefly
age in the Pacific coast region,
but these usually contain the metals in such a finely

divided condition, or in such combination, that they do not readily
lavas,
accumulate
in
stream channels.
Large quantities
and California.
of
placer
gold
are
obtained
from
Alaska
sources, we see that placer gold is obtained by dredging,

hydraulicking, and sluicing, as well as in small amounts from
dry placers in the southwest and beach gravels of California and Oregon.
Dredging, which was started in New Zealand about 1882, and first
Taking
all
drift-mining,
profitably tried in the Bannock district of Montana in 1893, is now of great

importance, the modern bucket elevator dredge (often electrically driven)
1
In decreasing quantity from frozen ground in Alaska, but
amounts frcm buried channels
in California.
still
in considerable
GOLD AND SILVER
679
being capable of excavating as much as 10,000 cubic yards daily, and the
buckets each having a capacity of 16 cubic feet. The total value of gold
in millions of dollars produced in this manner by several states up to date
is:
Montana,
2.
Dry
6;
Idaho, 3; Colorado,
or Siliceous Ores.
silver ores proper;
(6)
2;
Alaska, 10; California, over 71.
These include:
The
(a)
gold and
fluxing ores carrying considerable quan-
iron and manganese oxides with small gold and silver

contents; and (c) precious-metal bearing ores with copper,
lead and zinc in small amounts.
Colorado, California, Nevada,
South Dakota, and Alaska have been the largest gold prpducers
tities of
of this type.
The
siliceous gold ores are in part free milling
and Oregon;
California,
in
(amalgamating) as Alaska,
part both amalgamating and concentrating;
in part simply concentrating, as parts of Colorado and Arizona; in increasing

part all-sliming and cyaniding; and in part smelting.
A great deal of the silver from the gold-silver siliceous ores is obtained
with the gold by amalgamation and cyanidation, the silver being recovered
The remainder is obtained by smelting rich
refining the mill bullion.
by
ores
and
refining copper or lead bullion produced.
Nevada
much also
yields now over one-half the silver production, but

conies from Colorado.
The siliceous ores are of varying age. Those of California,

Oregon, and Alaska are Mesozoic and associated chiefly with
monzonite,
quartz
granodiorite,
and
diorite.
Another great
post-Miocene age, found chiefly in Colorado, Nevada,

and Montana, is associated with Tertiary lavas and characThe most productive ones carry fluorite
terized by Bonanzas.
class of
and normally
also tellurides.
in others, silver.
In some, gold
may
predominate;
is found
third class, of pre-Cambrian age,
states, Wyoming, and South Dakota, the last

mentioned including the famous Homestake mine.
3. Copper ores, usually with over 1\ per cent copper, but
with less in the case of the western disseminated ores and those
of Lake Superior.
in the Atlantic
The
largest gold producers are those of
and Montana.
The
silver
production
Utah, Arizona, Nevada,

comes from the elec-
refining of Michigan copper, and blister copper produced by smelting. The great disseminated deposits of Utah,
Arizona, Nevada, and New Mexico are yielding increasing quantities, while the vein deposits of Butte, Mont., are also im-
trolytic
portant.
ECONOMIC GEOLOGY
680
The
gold- and silver-bearing copper ores exhibit great differences in form and age; neither do all the occurrences yield
much gold or silver, and, moreover, they are of more importance
as gold producers, silver being less often associated with the
copper.
4. Gold- and Silver-bearing lead ores, containing 4^ per cent
The
gold is obtained chiefly from Utah and

comes
Colorado.
mainly from the lead-silver ores
Utah
of Coeur d'Alene, Idaho,
(chiefly Park City and Tintic),
Most of the output is obtained
and
Colorado (Leadville
Aspen)
or
more
of lead.
The
silver
by the de-silverization of lead bullion.

These are unim5. Copper-lead or Copper-lead-zinc Ores.
The
with
the
others.
as
gold supply is small,
compared
portant
and the main silver supply is from Colorado and Nevada.
6.
yield
Zinc
containing at least 25 per cent zinc. These

gold, and the silver which is obtained mainly as a
ores,
little
by-product from the smelting of zinc concentrates

chiefly
is
obtained
from Nevada, Montana, and Arizona.
Since gold and silver ores vary so in their mineralogical

richness, the metallurgical processes involved in their extraction are varied and often complex.
Extraction.
associations
and
Those ores whose precious metal contents can be readily extracted after
crushing, by amalgamation with quicksilver, are termed free-milling ores.
This includes the ores which carry native gold or silver, and often repreOthers containing the gold as
sent the oxidized portions of ore bodies.
telluiide or containing sulphides of the metals, are known as refractory ores
and require more complex treatment. These, after mining, are sent direct
if sufficiently rich, but if not they are oiten crushed and
mechanically concentrated. The smelting process is also used tor rrixed
ores, the latter being often smelted primarily for their lead or copper conWhile in some cases
tents, from which the gold or silver is then separated.
there are smelters at the mines, still there is a growing tendency towards
the centralization of the industry, and large smelters are now located at
to the smelter
Denver, Salt Lake City,
etc.,
which draw their ore supply from many mining
districts.
Low-grade ores may first be roasted, and the gold then extracted by
leaching with cyanide or chlorine solutions. The introduction of the cyanide
and chlorination processes, which are applied chiefly to gold ores, has permitted the working of many deposits formerly looked upon as worthless,
and in some regions even the mine dumps are now being worked over for
It is estimated that in 1914 $28,629,147 worth of gold
their gold contents.
The chief fields are in the Cripple
bullion was recoverd by cyanidation.
Creek region of Colorado; the

Montana; Bodie, California; and
De Lamar
in Arizona.
district,
Idaho;
Marysville,
GOLD AND SILVER
681
The most important gold-milling centers of the United States are the
Mother Lode district of California; the Black Hills, South Dakota, and
Douglas Island, Alaska.
The value of ore and bullion is determined from a sample assay, and the
smelter, in paying the miner for his ore, allows for gold in excess of $1 per
ton of ore at the coining rate of $20.67 per ounce, and for silver at New
York market price, deducting 5 per cent in each case for smelter losses.
Lead and copper are paid
made
there
for in the
same manner, as are
a sufficient quantity present.

for zinc, and, in fact, a deduction is made
if
ganese,
is
No
also iron
allowance
if it
and man-
however,
exceeds a certain per
is,
cent.
Distribution of Gold and Silver Ores in the United States

(Fig.
leran
Gold ores are widely distributed in the Cordil237)

and Appalachian regions, while the silver ores are found
.
Eat. Co.. 75 S. V
FIG. 237.
Map
showing distribution of gold and silver ores in the United States.

(Adapted from Ransome, Min. Mag., X.)
between the Great Plains and Pacific coast ranges, exThis occurrence in two
widely separated areas is brought oat in an interesting manner
chiefly
clusive of the Colorado plateau region.
in Fig. 237.
More than
one-half of the United States production of gold
conies from three
states
California, Colorado, and Nevada.
In these, however, the ores vary widely in their mineralogical
associations, the gold occurring mostly in combination with
silver, lead, copper, and zinc ores, but also at times free, or, in
the most productive district, as a telluride.
ECONOMIC GEOLOGY
682
The
Pacific
belt,
supplies about
of gold produced, the famous
excluding Alaska,
amount
cent of the total
25 per
Mother
Lode region, mentioned later, being the most important producer.

Alaska yields about 17 per cent, and the Basin Range province
nearly 22 per cent, collected from widely separated deposits in
Utah, Nevada, Arizona, and New Mexico, and in which the
gold is associated with copper, silver, or lead.
About 49 per cent of the silver obtained in the United States
comes from the Rocky Mountain region, Idaho alone yielding
nearly one-fifth, while Montana supplies a little less. The Basin
furnishes something under two-fifths, nearly
one-half of this coming from Utah, especially from the Park
1
City mines near Salt Lake City (114).
Range province
The gold and

grouped under
silver occurrences of the
United States can be
five regions as follows:
Cordilleran Region.
This includes several types geologas
follows:
ically arranged
(a) belt of Pacific coast Cretaceoiis
1.
gold quartz ores, characterized by ores with free gold, and

auriferous sulphides, extending along the Pacific coast from Lower
California up to the British Columbia boundary.
The deposits
belonging to this are especially important in California, but

farther north, in Oregon and Idaho, the veins in many cases
have been covered up by the lava flows of the Cascade Range,
and those known
in that region differ somewhat from the California deposits in containing many mixed silver-gold ores and
also veins carrying auriferous sulphides without free gold.
The
ores of this belt are all of undoubted Mesozoic age, and are
accompanied by many extensive placer deposits, which have

been derived by the weathering down of the upper parts of
the quartz veins, the portions now remaining in the ground
representing probably but the stumps of originally extensive
fissure veins (113).
the deposits of this belt two groups stand out in some

prominence, namely, those of the so-called Mother Lode dis-
Among
of Nevada County.
Late Cretaceous or Early Tertiary deposits, occupying a
broad zone in the central and eastern part of the Cordilleran
While
region, and yielding gold ores of vaiying character.
from
and
characters
the
Pacific
in
coast
differ
ores,
age
they
trict
and
6.
These estimates
are, of course,
only approximate.
GOLD AND SILVER
683
and those of the belt next to be mentioned, nevertheless

they
are not absolutely separated from them
geographically.
The Mercur, Utah
(Fig. 246),
r ^SBJt*f*\
and Leadville, Colorado
(Fig.
\$&' <\p
SfKX
\
^
,'i
ittj
v\
\
,
l._
fti
>,
cuuin.f
T*^
*\
L u
v,
A s
vi
v
?-(Jto *.^
,^.
'
.^vg
1>_
-T^-'-^J
^n.it.-ii
Ffe>^
rt.nn
V.tASNwp9Sisfl|
feô^
L
-A x >f^S^5ESJCiTl
\ ^
koWaeraS^niut-^.^ tr'T
FIG. 238.
Map of California, showing location of more important mining districts
249), deposits, the latter referred to under lead and

zinc, are
included under this type.
The northward continuation of this belt of
gold-bearing veins
ECONOMIC GEOLOGY
684
in
Idaho and Montana presents somewhat
different types of
deposits, for there the veins are causally connected with great
batholiths of Mesozoic granite; and while the veins resemble
those of the Pacific coast in the quartz filling and free gold contents, they differ from the latter in containing more silver, and
often
large
quantities
of
In
sulphides with little free gold.
they are intermediate between
fact, in their geologic relations
the quartz vein and propylitic type. Of special prominence are

those of Marysville, Montana (so), and Idaho Basin, Florence,
This difference is more marked in the Montana
etc., in Idaho.
occurrences, in which the gold becomes subordinate and
tained as a by-prod act in silver mining.
is
ob-
(c) Eastern belt of Tertiary gold-silver veins, of greater importance than the preceding class and characteristic of regions
of intense volcanic acticity.
The veins cut across andesite
flows, or
more rarely
rhyolite
and
basalt.
They may
be entirely
within the volcanic rocks, or the fissures may continue downward into the underlying rocks, which have been covered by
Many of these Tertiary deposits

to the propylitic class, showing characteristic alterations
wail rock.
The ores are commonly quartzose, and
either gold or silver may predominate, the quantities
the extrusive masses.
belong
of the
though
of the
two metals are apt to be equal. Bonanzas are of common occurrence, and on this account the mines may be very rich but shortlived; still, the workable ore in many extends to great depths;
but is less rich than nearer the surface. Extensive and rich
placers are rarely found in the Tertiary belt of veins, for the
reason that the fine distribution of the gold is not favorable
to its concentration and retention in stream channels.
Deposits
of this type are worked in a number of states, including Colo-
Colorado
rado, Nevada, Arizona, New Mexico, and Idaho.
leads in the production of gold ores, for in no state are the
Tertiary deposits of the propylitic type developed on such a
scale.
2. Black Hills Region, the ores which are found chiefly in
the northern Black Hills, including: (a) Auriferous schists in
Cambrian conglomerates; (c) refrac(d) high-grade siliceous ores; and (e) placers.
Of these, the first and third are the most important.
The surface placers, being the most easily discovered, were
pre-Cambrian rocks;
(fe)
tory siliceous ores;
developed
first,
followed
by the conglomerates
at the base of
GOLD AND SILVER
685
the Cambrian. 1
These are found near Lead, occupying depresand the material is thought to
have been derived from the reef formed by the Homestake
These deposits are of interest as
ledge in the Cambrian sea.
the
oldest
being probably
gold placers known in the United
The fact, however, that the matrix of the gold-bearing
States.
portion of the conglomerate is pyrite rather than quartz, and
sions in the old schist surface,
the occurrence of the gold along fractures stained by iron, has

led some to believe that the gold has been precipitated chem-
by the action of iron sulphide and is not a detrital product.

Eastern Crystalline Belt (114).
Gold, with some silver,
has been found in the rocks of this belt from Vermont to Alaically
3.
bama, but the deposits are of little importance except in North

Carolina (96-97), South Carolina (106, 107), Georgia (69-71), and
Alabama
(22, 23), in
other words, in the southern Appalachian

but even in this part of the area the
and Piedmont region;
deposits are not found everywhere, but are restricted to three

belts (Becker), viz.: (1) the Georgia belt, extending from Mont-
gomery, Alabama, across northern Georgia to North Carolina;

(2) the South Mountains region of North Carolina;
(3) the
Carolina belt, lying to the eastward of the others, and extending from South Carolina northeastward through Charlotte,
North Carolina, and continued in Virginia; at least the Virginia deposits
lie
in part in the line of strike of this zone.
It will be seen from the preGeologic Comparisons (i3a).

ceding pages that the ores of South Dakota and the Appalachians belong to an older group whose age ranges from preCambrian to Paleozoic, and to which belong also the gold ores
Nova
of
Scotia, Ontario,
of the deposits of Brazil
American countries.
and Quebec. Here too belong many

and other eastern and northern South
Representatives of this group are
known
also in other countries, notably Australia.
The other North American occurrences belong to a younger

group of late Mesozoic to Quaternary age. Few representatives
of this class are found in Canada, but they yield the enormous
silver
the
supply of Mexico, and many are

of South America.
known and worked
in
Andean region
Other important occurrences are worked in Hungary,
New
Zealand, etc.
1
These are referred to as cement mines, owing to their partly cemented
character.
ECONOMIC GEOLOGY
686
Contact-metamorphic Deposits
Gold and
be present in small amounts in copper

but ore bodies of this type containing the
noble metals as important constituents are rare.
Such a case has, however, been recorded in the Cable mine
silver
may
deposits of this class,
in the. Philipsburg quadrangle
of
Montana
(78a),
where
the
body occurs in limestone surrounded by quartz-monzonite.

The chief non-metallic minerals are calcite, quartz, barite,
ore
and dolomite, with
pyrite, chalcopyrite, pyrrhotite, arsenopyrite,

magnetite, specularite, and gold as the primary metallic ones.
Contact silicates also occur.

Of considerably greater importance
Nickel Plate
Mine
is the ore deposit of the

at Hedley, British Columbia (135), which
The ore deposits occur at the contact of
of a rare type.
dikes and sheets of gabbro in Carboniferous limestones (Fig.
239) which are interbedded with quartzite, shale and volcanic
is
The ore bodies, which are of irregular outline, contain

arsenopyrite, with chalcopyrite, pyrrhotite, blende, pyrite, native
gold and tetradymite (P^Tes). The gangue includes garnet,
tuffs.
epidote, diopside, amphibole, quartz, calcite,

gold averages $11.00 per ton.
and
axinite.
The
Other deposits of this group are auriferous tellurides at Elkhorn, Montana, and deposits
bornite at Chiapas, Mexico. 1
of
argentiferous
and auriferous
Deposits of the Deep-vein Zone
These include deposits, chiefly in the form of fissure veins,

precipitated under high-temperature conditions, either in cavities
In most of the deposits belonging to this
or by replacement.
than silver.
more
abundant
class, gold is
and
silver ores of this class are not
Gold
United States.
in
United
the
abundant
States, but include some wellvery
known
deposits.
The deposits at this locality are

Peak, Nev. (92).
so closely associated with igneous rocks that Spurr classed them
as magmatic segregations
(p. 92), but some may feel that
in
be
better
the deep-vein zone class. The ore
put
they might
Silver
occurs in lenticular masses and fissure veins of quartz, which

1
McCarty,
Inst.
Min. and Met., London, Trans. IV: 169, 1895.
PLATE LXIII
FIG.
1.
Mill of Nickel Plate mine, Hedley, B. C.
ground.
FIG.
2.
Mines on ridge
in back-
(H. Ries, photo.)
Virginia City, Nev., Mt. Davidson in rear, on whose lower slope the
Comstock Lode outcrops. (H. Ries, photo.)
(687)
688
ECONOMIC GEOLOGY
a
b
grade into alaskite and this in turn into granite, so that the
quartz represents the end-phase of the intrusion. The gold
X
* JsIS
E -gSU
.
Jli
tf-g-os
KocS
ECONOMIC GEOLOGY
690
occurs chiefly in the quartz.
country rock.
South Dakota.
The gold
is
the main
Homestake
belt (109,
Paleozoic limestone
ores of the
which are the most important in the Black Hills, occur

in a broad zone of impregnated schists, containing many quartz
lenses, alternating with dikes of fine-grained rhyolite, which
also formed sheets in the Cambrian sediments overlying the
schists, and now remain as a resistant cap on many of the surrounding ridges (Fig. 240). The ore, which is all low-grade,
averaging about $4 per ton, is usually a mixture of quartz,
110),
CEMENT MINES
Homestake belt at Lead, S. Dak., showing realtion

ancient and modern placers to Homestake lode.
(From Min. Mag., XI.)
FIG. 240.
Section of
of
and occasionally other minerals having no definite conit, occupying a zone in the Algonkian rocks which
shows greater hardness, irregularity of structure, and mineralization than the surrounding schists.
The boundaries are poorly
defined, and superficial examination may fail to distinguish
between ore and barren rock. In the upper levels the ore seems
to be with the dikes, but diverges from them in depth, and
there is apparently no genetic relation between the two.
In
the earlier days the ore encountered was oxidized and freemilling, but the appearance of sulphides with depth has neces-
pyrite,
nection with
sitated the introduction of the cyanide method of extraction.

ore was originally worked as an open cut (PI. LXIV), but
The
by underground methods.
In 1914 the output of this mine was 1,587,774 short tons of
ore milled, with $6,160,161 of bullion recovered, the ore value
per ton being S3. 87.
later
The crystalline belt of the southern

Appalachian Belt (114).
contains
numerous
Appalachians
quartz veins, some of which
GOLD AND SILVER

are of lenticular
deposits
in
character.
silicified
schist.
691
There may also be replacement

placers derived from these
The
have yielded considerable gold in the past,

in
Georgia, Virginia, and North Carolina, but the vein
notably
has
been less productive. It is doubtful whether all
mining
the veins belong to the deeper-vein zone, some probably having
been formed at intermediate depths.
In the Carolina belt Graton (106) states that the quartz
quartzose
ores
more or less pyrite occur in dense metamorphic

and
most commonly in amphibole or gabbro closely
rocks,
The
related to it, and formed by the filling of fracture spaces.
usuand
have
a
conform
which
are
steep dip,
irregular
veins,
ally somewhat closely to the strike and dip of the inclosing
veins with
rocks.
Similar occurrences are found in the other belts of the southern
Appalachians, and some, as those at Gold Hill, North Carolina,

have shown copper with depth, so that they were worked for
both metals.
The replacement type, which is important in the Carolina belt,
is less common but more productive than the preceding, and
with one or two exceptions is found in volcanic rocks, mostly
tuffs.
The porous nature and easily alterable character of these,
especially the tuffs, has allowed widespread penetration and replacement by the ore solutions, which deposited chiefly silica and
pyrite.
The ore bodies are usually large, and range from 40 or 50 to hundreds of feet in length, and 20 to several hundred feet in width; but
their outline is rudely lenticular.
At the Haile Mine
in South Carolina, which belongs to this type,

a quartz-sericite schist, which has been derived
by foliation from a porphyry tuff which had an original well-bedded
structure that is still preserved in some cases.
The silicification
the country rock
is
appears to correspond in intensity with the amount of foliation,

although in cases of extreme silicification all traces of former structure have been quite destroyed, and the rock is simply a massive
Several dikes of diabase cut the schist.
siliceous hornstone.
The
ore consists of large lenses of altered tuff, which have been

and pyritized, the two processes having gone on at the same
silicified
now consists of a fine-grained aggregate of

quartz and pyrite with scattered fibers of sericite. The replacement is not uniform. The gold occurs (1) mainly as native gold
time, so that the rock
ECONOMIC GEOLOGY
692
originally deposited, (2) free gold derived

inclosing pyrite, and (3) gold in pyrite.
from oxidation
of the
This mine, which has been worked more or less continuously

since about 1830, has been one of the most important producers
in the southern Appalachian region.
The copper deposits of the Cactus Mine,
Other .occurrences.
Utah; Copperopolis Calif; and Meadow Lake, Calif, yield not

a little gold, but copper as well, and are mentioned under the
latter.
Alaska (24).
Although gold has been known to occur in
Alaska since the early part of the century, and was even worked
in 1860, its production is not definitely stated until 1880, when
FIG. 241.
Map
showing mineral deposits
of Alaska.
(After Brooks, U. S. Geol.
Surv., Bull. 250.)
was added to the
list of gold-producing regions, with an outwhich

since that time has increased many times
put
until
it reached a maximum of $22,036,794
but
not
over,
steadily,
in 1906, and had dropped to $15,764,259 in 1914.
The first gold was discovered on the islands of the Alexander
Archipelago and along the adjoining coast, but subsequently prospectors found their way into the interior, the first strikes there being
it
of $20,000,
GOLD AND SILVER
693
made in British Columbia near the head of the Stikine River. These
were followed by discoveries in the Yukon Valley, especially along
some of the tributaries known as Birch Creek, Mission Creek, and
Forty Mile Creek. In 1896 still richer discoveries were made along
the Klondike River, and within one year the yield of this region
had exceeded the purchase price of Alaska. Other discoveries
have since followed rapidly.

At the present time approximately 68 per cent of the value
of the gold produced in Alaska is obtained from placers, 31 per
cent from quartz ores, and the balance from copper ores.
The gold quartz lodes, which are
Auriferous Lodes (32)
most prominent along the coast (Fig. 241), were first discovered
near Sitka in 1897, but the first important production came from
the Tread well mine on Douglas Island southeast of Juneau
.
(32) in 1882.
The geology of this region bears in many ways a strong resemblance to the California gold belt, but the ores differ in
FIG. 242.
Sketch
map
of
Douglas Island, Alaska.
(After Spencer, U. S. Geol.
Sure., Bull. 259.)
origin.
The
section involves a series of steeply dipping slates

diorite dikes.
The ore bodies (Figs. 242,
and greenstone and
243) are dikes of albite-diorite, permeated with metallic sulphides

and carrying small amounts of gold, with a hanging wall of green-
stone and a foot wall of black slate. The veinlets, which are
thought to have been formed by shearing stresses incident to
epeirogenic movements, occur in two sets of fractures at right
ECONOMIC GEOLOGY
694
angles to each other.
Spencer believes that the mineralization

has been caused by hot ascending solutions of magmatic origin.
Secondary concentration is not in evidence, and it is thought that
the depth to which the ores can be worked will depend more
on the increased cost of mining at great depths than on exhaustion
of the ore.
The workings on Douglas Island extend
for a
distance of
Gold also occurs in quartz veins along the cost.

The southeastern Alaska gold ores are placed in this group
because of the character of the gangue minerals and alteration
7000
feet.
of the wall rocks.
DIORITE
* BOWLD
-^
CLAY
SLATED GREENSTONE
i
Cross section through Alaska Treadwell mine on northern side of

(After Spencer, U. S. Geol. Surv., Bull. 259.)
FIG. 243.
Douglas Island.
A number
Canada.
in Ontario
are of
much
The
(126,
importance.
known
The ore
best
Ontario.
127,
of auriferous quartz veins are known

and Quebec (138), but few of them
137)
deposits are those of the Porcupine district,

bodies which occur in the metamorphosed
sediments of the Temiskaming
series,
and schistose volcanics
of the Keewatin, consist of lenticular veins, irregular veins and

domelike masses of quartz, carrying native gold together with
pyrite and some other metallic sulphides, with which are associated calcite, dolomite, sericite, chlorite, tourmaline, and quartz.
The gold and pyrite appear to have been deposited about the
same time, and
especially in the crushed portions of the quartz

or the schist bordering these.
The annual production of this
district
now
exceeds $4,000,000.
Other gold quartz veins are known in the Lake of the Woods
(145) and Rainy Lake districts (137), also at Lakes Abitibi
(145) and Larder Lake (147).
The
deposits at Rossland, B. C., referred to under copper,
also yield
an appreciable quantity of gold.
GOLD AND SILVER

695
West Australia contains several gold mining

districts, that of Kalgoorlie being the most important, the others including
The rocks are chiefly crystalline
Pilbarra, Murchison, and Mount Margaret.
1
from igneous rocks and granites together with altered sedimentaries, but the gold deposits are found chiefly in the schists. Two
types are recognized, viz.: (1) Quartz veins in amphibolite, or at its contact with granite, and (2) lodes, formed by ore deposition along shear zones.
schists derived
The
first class carries
native gold, galena, blende, pyrrhotite, chalcopyrite,
arsenopyrite, stibnite, bismuthinite, pyrite, scheelite, chlorite, calcite, sericite,

and sometimes tourmaline; the latter has native gold, tellurides, pyrite,
blende, galena, pyrargyrite, magnetite, siderite, ankerite,
tourmaline, albite, etc. The wall rock bordering the lodes has
been noticeably altered.
Brazil contains several deep gold mines in the province of Minas Geraes,
chalcopyrite,
sericite,
of which the Morro Velho is not only the most important, but also the
2
The
deepest in the world, having reached a vertical depth of 5800 feet.
ore deposits are quartz veins in Archaean schists, gneisses and granites, or
in
sedimentary schists and quartzites.

India.
The pre-Cambrian veins
in
crystalline
schists
of
the Kolar
3
gold fields in Mysore, India, also belong in this group,
Deposits Formed at Intermediate Depths
This group includes a number of auriferous quartz veins,

carrying free gold, pyrite, and even other sulphides, but lacking
the silicates characteristic of the deep-vein zone. The quartz
veins do not, as a rule, show a high silver content.
Alteration
sometimes occurs, resulting in the development

and pyrite.
Mother Lode Belt (45, 52)
United States.
California.
This includes a great series of quartz veins, beginning in Mariposa County and extending northward for a distance of 112
The veins of this system break through black, steeply
miles.
dipping slates and altered volcanic rocks of Carboniferous and
Jurassic age (Fig. 244), and since they are often found at a considerable distance from the granitic rocks of the Sierra Nevada,
they have apparently no genetic relation with them. The veins,
which occur either in the slate itself or at its contact with diabase
dikes, show a remarkable extent and uniformity, due to the
of the wall rocks
of sericite, carbonates,
West Austral. Geol. Surv., especially Nos. 6, 14, 15, 20, 22, 23,
also Lindgren, Econ. Geol., I: 530, 1905; Maclaren and Thomson,
Sci. Pr., CVII: 45, 1913; Larcombe, Ibid., CXI: 238, 1915.
Bulletins of
45, 46, 51, 56;
Min. and
2
Harder and Leith, Jour. Geol., XXIII: 341 and 385, 1915; also Lindgren
Amer. Inst. Min. Engrs., Bull. 112: 721, 1916.
3
Hatch, Geol. Surv., Ind.,
Mem.
33, 1901.
ECONOMIC GEOLOGY
696
fact that in the tilted layers of the slates there were planes of
weakness for the mineral-bearing solution to follow. The ore
is native gold or auriferous pyrite in a gangue of quartz, and
the average value may be said to vary from $3 to $4 up to $50
or $60 per ton.
The veins often split and some of the mines
have reached a depth
Map
FIG. 244.
of several
and section
thousand
of portion of
feet.
Mother Lode
Pgv, river
district, Calif.
Ng, auriferous river gravels. Sedimentary rocks

Jm, mariposa formation (clay, slate, sandstone, and conglomerate) Cc, calaveras formation (slaty mica schists).
Igneous rocks Nl, latite Nat, andesite
ma,
tuffs, breccia, and conglomerate
mdi, meta-diorite
Sp, serpentine
meta-andesite ams, amphibole schist.
(From U. S. Geol. Surv., Atlas Folio,
Mother Lode sheet.)
gravels, usually auriferous
Nevada County
(48).
In Nevada County the mines of Grass
Valley and Nevada City are likewise quartz veins (PI. LXV, Fig. 2)
but they occur along the contact between a granodiorite and diabase porphyry, as well as cutting across the igneous rock (Fig. 245).
Two systems of fault fissures occur, and in these the ore is found
form or associated with metallic sulphides. The

the
vein
width
averages from 2 to 3 feet, and the lode ore
in
occurs
well-defined bodies or pay shoots.
The vein
generally
hot
was
rocks
and
the
while
wall
filling
deposited by
solutions,
either in native
of
PLATE
FIG.
FIG. 2,
1.
LXV
Kennedy mine on the Mother Lode, near Jackson,
Calif.
Auriferous quartz veins in Maryland mine, Nevada City, Calif.

Lindgren, U. S. Geol. Sure., 17th Ann. Rept., III.)
(After
(697)
ECONOMIC GEOLOGY
698
contain the rare metals in a disseminated condition, Lindgren (48)

believes that the ores have been leached out of the rocks at a considerable depth.
The mines at Nevada City and Grass Valley
have been large producers of gold and some silver. Placer mines
have furnished a small portion of the product, but at the present
day these
latter are of little importance.

In Oregon, the quartz veins are worked in Baker County, which
is the most important gold-producing
region of the state (104, 105).
Gold ores with sulphides in quartz gangue are worked in the Monte
Cristo district of
Washington
(122)
GRANODIORITE
METAMORPHIC
SCHIST AND DIABASE
O. MERRIFIELD VEIN fe.URAL VEIN C.SLATE VEIN
Section illustrating relations of auriferous quartz veins at Nevada

City, Calif.
(After Lindgren, U. S. Geol. Surv., 17th Ann. Kept., II.)
FIG. 245.
Cambrian Ores (109, 111).

The
ore is found in the region between
Yellow Creek and Squaw Creek, and yielding about two-thirds
The deposits, which occur
as much gold as the Homestake.
as replacements in a siliceous dolomite (Fig. 247), are found at
two horizons, one immediately overlying the basal Cambrian
quartzite, and the other near the top of the Cambrian series.
The ore forms flat banded masses known as shoots, and varying
in width from a few inches to 300 feet.
It is overlain by shale
with
a
or eruptive rock, and associated
series of vertical fractures,
of the wall rock.
silicification
made prominent by a slight
These
which
are
are termed verticals,
supposed to have confractures,
South Dakota.
Siliceous
refractory siliceous
Cambrian
ducted the ore-bearing solutions.

The ore is a hard, brittle rock, composed of secondary silica,
with pyrite and fluorite, and at times barite, wolframite, stibnite,
and
from $3 or $4 per ton

with
an
$100 per ton,
average of $17. Other,
jarosite.
to in rare cases
Its contents range
ss
cs
v;
OJ
"<
'
r
fc
o e
"ft
ECONOMIC GEOLOGY
700
but
less
important,
siliceous ores
occur in the Carboniferous
rocks.
Mercur, Utah.
FIG. 246.
district in
Map
The
of Utah,
gold-silver
mines of the Mercur
showing location of more important mining
(117)
districts.
Utah form perhaps the most important occurrence in

Here the Carboniferous limestones, shales, and
this central zone.
sandstones, representing about 12,000 feet of sediment, are folded

Near the center of the section is
into a low anticline (Fig. 248)
.
the great blue limestone, carrying an upper and a lower shale bed.
GOLD AND SILVER
701
Quartz porphyry has intruded the limestone, and, at two places

especially, spread out laterally in the form of sheets, on whose under
side the ore is found, the silver ores under the lower sheet, the gold
&?&
"*
-*
r/U/C> Tx,> /I
6VL'/^C/T\
Vx-x'-U-^'-N-
4/>^-S
/
DOLOMITE
COMPARATIVELY
CONGLOMERATE
IMPERVIOUS SLATE
FIG. 247.
HARD
QUARTZITE
ALGONKIAN
SCHIST
Typical section of siliceous gold ores, Black Hills, S. Dak.

Irving, U. S. Geol. Sura., Prof. Pap. 26.)
(After
ores under the upper one, about 100 feet above the first.
The
silver ore is cerargyrite and argentiferous stibnite in a silicified belt
The gold is native and occurs in a belt of residof the limestone.
ual contact clay, near northeast fissures cutting the limestone,

being oxidized in places and accompanied by sulphides in others.
LOWER LIMESTONE
FIG. 248.
Section at Mercur, Utah.
(After Spurr, U. S. Geol. Sun., IQth Ann.
Rept., II.)
The
ore runs 1-19 ounces of silver per ton, and 2-3 ounces of gold,
with a gangue of quartz, barite, limonite, and arsenical sulphides.
The
thought to have been deposited by heated

which came up along the igneous sheet some time after
its intrusion, and the deposition of the gold ore is believed to have
taken place some time after the silver was deposited. Some doubt
silver minerals are
solutions
ECONOMIC GEOLOGY
702
exists as to the exact source of the ascending waters,
but
in all
probability they were derived from some deep-seated cooling

mass cf igneous rock. The ores are especially suited to the
cyanide treatment.
Georgetown, Colorado
Clear Creek County (Fig. 249),

(68).
which Georgetown lies, is, next to Gilpin County, the oldest
mining district in Colorado, if not the entire Rocky Mountain
in
region.
There are a number of mining camps in this area, including

Georgetown, Idaho Springs, Silver Plume, Central City, etc.,
FIG. 249.
Map
showing approximate distribution
and gold regions
of Colorado.
of
the principal
silver,
lead
(After Spurr.)
but the only area which has been described in detail is that
The conditions here,
included in the Georgetown quadrangle.
however, are in a general \vay similar to those existing in ether
parts of the district.
The earliest rocks of the district consist of a series cf preCambrian schists, the oldest ones (Idaho Springs formation)
being probably of sedimentary origin, but the later ones meta-
morphosed igneous
rocks.
This series has been successively injected by about eight types of

plutonic rocks ranging from granites to diorites.
GOLD AND SILVER
703
M
~
&
Following these, in late Cretaceous or early Tertiary, came the

intrusion of a series of porphyry dikes which are as varied in
their composition as the plutonics.
These porphyries are of
more than
local interest
because they form part of a wide
ir-
ECONOMIC GEOLOGY
704
regular zone that extends in a general northeast-southwest direction from Boulder to Leadville and then on to the San Juan region
(Fig. 249J.
It will thus
districts lie within
The ore-bearing
in
be seen that
many
important mining
it.
fissure veins
(PL LXVI)
which
may
occur
of the older schistose rocks of the district, are divisible
any
two groups, viz., argentiferous blende-galena ones with little
The
gold, and auriferous pyrite veins with or without silver.
into
former predominate in the Georgetown region, the latter southwest of Idaho Springs, but the two types of ore are occasionally
known to occur in the same vein. Both types of veins are seen
to show a general agreement in trend and distribution with
the porphyry dikes (Fig. 250), and the vein formation is thought
by Spurr not only to have followed the porphyry intrusions,
but to show characteristic petrographic associations. That is,
the silver-galena-blende veins are related to dikes of alaskite
porphyry, granite porphyry, quartz -monzonite porphyry, and
dacite;
the
auriferous
pyrite veins with
bostonite,
alaskite,
and alkali syenite.

The two classes of veins show the same primary minerals
(galena, blende, and pyrite), but the proportions of them in
each differ, and they have the same bonanzas, wall rocks, and
quartz monzonite, biotite
latite,
gangue minerals (mainly quartz)

It is suggested by Spurr that the alteration of the wall rocks
was caused by descending atmospheric waters, changing them
to mixtures of quartz, sericite, carbonates, and kaolin, and the
gangue minerals have, moreover, come from the walls; but
.
while the source of the metals in the silver veins
is in doubt,
Spurr considers that the metalliferous minerals of the gold veins
were contributed by magmatic waters.
Crosby has questioned whether the gold and silver veins
represent distinct classes, and points out that since the former
outcrop at low levels, they may simply represent the basal
portions of silver veins, these being known to outcrop only at
the higher points in the district.
The rock formations are somewhat
Gilpin County (54)
.
similar to those of the
Georgetown quadrangle, as are also the

which are grouped by Bastin and Hill
as: (1) Pyritic ores; (2) galena-sphalerite ores; and (3) composite ores, carrying the minerals of both the other classes, and
gold-silver ore veins,
being the result
of
dual
mineralization.
Most
of
the veins
GOLD AND SILVER
705
occupy zones of minor faulting the ore deposition having been

partly by filling and partly by replacement.
FIG. 251.
Map of Colorado, showing location of mining regions.

Amer.
Canada.
Nova
Inst.
Scotia
Min. Engrs. Trans.,

(140,
146).
(After Richard,
1904.)
The gold
veins
of
this
province, which form a belt along the south coast, occur in

folded Cambrian (?) slates and quartzites which have been
intruded by Silurian (?) granites. The veins, which are often
saddle-shaped, are usually found along the axes of plunging
anticlines, and most of them are parallel to the stratification.
Some show a strong crenulation supposed to be of post-mineral
character, and small veins often pass outward from the main
ones.
The ore mineral is native gold, in quartz gangue, and
associated with pyrite, chalcopyrite, galena, blende, and arsenoWhile the ore is supposed to be due to cavity filling,
pyrite.
Faribault believes that the veins are younger than the granite,
but Rickard holds that they are later.
known
gold districts,
viz.,
Victoria. 1
This colony contains two wellIn both we find
those of Bendigo and Ballarat.
1
Rickard, Amer. Inst. Min. Engrs., Trans. XX: 463, 1891; Lindgren, Eng. and
Min. Jour., Mar. 9, 1905; Vogt, Krusch und Beyschlag, Lagerstatten, II: 107,
1912.
ECONOMIC GEOLOGY
706
strongly folded Ordovician slates and

sandstones cut by a batholith of
or
granite
At
monzonite.
quartz
especially the ore bodies

saddles along the axes of anti-
Bendigo
show
clines,
there being not only several

these saddles, but in each
lines of
number, one below the other.

The
Other irregular veins occur.
ore is gold-bearing quartz, with
line a
and
associated pyrite
arsenopyrite,
These reefs, as
they are called, have been worked to
a depth of 4500 feet, but are much
richer in the first 2500 feet.
and some
albite.
At Ballarat, the gold-quartz veins

show more irregularity of form, and
the rich ore often appears to be at
the contact of flat bodies of quartz
with thin veins of pyrite, or carbo-
naceous seams
known
the
in
slate,
both
as "indicators."
Other important Australian disare those of Charter Towers,

Queensland, and Hill End, New
South Wales.
tricts
Queensland.
The
ore
body at
Mount Morgan, Queensland
is
to
be classed as one of the interesting

occurrences of the world.
many years as
now shows signs
for
it
copper.
limonite
free gold,
crumbly,
gold
Worked
deposit,
changing to
rich gossan of
of
Below a
and manganese carrying
there is a mass of porous,
siliceous
rock,
carrying
gold and some silver, which is in

Thi^ at depths
the oxidized zone.
of 200 to 300 feet grades into a
mixture of pyrite and chalcopyrite,

While several theocarrying gold.
ries of origin have been advanced,
it
can probably be regarded as
MfcUiiifin
and
replacement,
ionally placed
in
is
provisthe intermediate
group.
1
Rickard, Amer. Inst.
Min. Engrs.,
schlag, Lagerstatten, II: 134, 1912.
XX:
133, 1891;
Vogt, Krusch and Bey-
GOLD AXD SILVER
707
DETAIL SECTION
Showing the structure of quartz crumple and "feeders" at east face of drift
on Borden lead, from actual measurements and photographs, 10th Sepf. 1903,
by E.R. Faribault
FIG. 253.
Tranbverse section of a part of West Lake Mine, Mount Uniake,

N. S. (After Malcolm, Can, Geol. Suro., Mem. 20-E.)
ECONOMIC GEOLOGY
708
Deposits
Formed
Shallow Depths
at
These include a great number of gold

and silver deposits, in which the two
metals mentioned are present in varying
proportions, and always associated with
The group correTertiary volcanics.

sponds to the young gold-silver group of
1
Vogt, Krusch, and Beyschlag.
The
rocks
wall
zation,
may show
propylitiin rarer cases,
or
silicification,
Sericitization
alunitization.
is
also
Quartz is the commonest gangue

mineral, but carbonates of lime, iron,
noted.
or
manganese, as well as adularia are

The gold may be native, or
combined with tellurium, while the sil-
noticed.
ver
is usually present as sulphides, sulpharsenides, or sulphantimonides.
As
United States.
stated on p. 684,
the ores of this group are of great importance in the western United States.
Nevada
Goldfield,
field
lies
near
Gold-
89).
(88,
the
eastern
border
of
Esmeralda County (Fig. 232), on the

southern rim of one of the typical desert basins of the region which connects,
through a low pass on the north, with
a still larger basin west of Tonopah.
The
geologic structure
the district
is
essentially of
quite
(Fig.
simple,
254)
of
consisting
a low dome-like uplift of
Tertiary lavas and lake sediments, resting on a foundation of ancient granitic
and metamorphic
The kind
of
rocks.
rocks
in
this
district,
and relationships are shown in

the map and section given by Eansome
their age,
The
oldest or
(Figs.
255,
256).
brian
beds
were intruded
Lagerstatten, II: 12, 1912.
by
Cam-
alaskite
GOLD AND SILVER
709
at about the close of Jurassic time, and there then followed a

long interval of erosion before the eruption of the Tertiary lavas.
It will be seen
in
some
Khj-olit,
(Liter
flows;
FIG. 255.
The
from the section that the same type

more than once.
of rock
was
Ransome, Econ,
Geol.)
cases erupted
Volcanic Quartz lathe, Daeite

AnHesite Rhyolite
Siebert
Quartz
tuffs.
breccia (Flows with (Intru- (Later flows (Earlier
basalt.
same
flow witb
sive masses) and
(Lake bed: (Flows inter- (Roughly
bedded
intrusions) intrusiv.
including calated la
rhvolite)
misses an
local
thin flowg
Siebert
tufls)
tuff)
ofrhjrolite)
deposit)
.
Geologic,
ores
Map
of this
of Goldfield, Nev., district.
district,
(After
Andesitfl
(Earlier
Sows)
which are of somewhat complex

and pyrite accompanied by
character, consist of native gold
minerals containing copper, silver, antimony, arsenic, bismuth,

tellurium, and other elements.
The
closely
some of the ores, in fine particles

crowded together and forming bands or blotches in the
free gold occurs in
ECONOMIC GEOLOGY
710
gangue, and is not likely to be recognized as such until

examined with a lens. The common associated minerals are
At times the
pyrite, marcasite, bismuthinite, and famatinite (?).
rich ore shows a curious concentric crustification, consisting of
flinty
Malpais basalt
Unc'f'y
Rabbit Spring formation

Spear head rhyolite
Pozo formation
Unc'f'y
Siebert formation
Mira basalt
Siebert formation
Meda
\
rhyol'te and.
Unc'fy
overlapping andesite breccia

Dacite vitrophyre
Chispa andesite
Dacite vitrophyre
Mill'town andesite
and
intrusive dacite
1-
Sandstorm
f-
1-
Unc'f'y
rhyolite
cut by dacite and
Morena
rhyolite
Kendall tuff
cut by dacite
Latite cut by dacite
and Morena
rhyolite
Vindicator rhyolite
Alaskite and granite
intrusive into
Cambrian shale
FIG. 25G.
Long
erosion
interval
Generalized columnar sectio n of geological formations at Goldfield,

(After Ransome, U. S. Geol. Surv., Prof. Pap. 66.)
Xcv.
fragments of silicified, alunitized, and pyritized rock, covered

with shells of gold and sulphides.
The ore bodies, which are noted for their remarkable richness
and
irregularity (PI. LXVII) are closely related to fissures, usually

of irregular trend, but not representing fault planes.
The deposits (PI. LXVII) are defined as irregular masses of
altered
and mineralized rock, traversed by multitudes
irregular, intersecting fractures,

places into brecciation.
of
such fracturing passing in
small
many
6*
1
B
ECONOMIC GEOLOGY
712
These irregular masses are termed ledges (Fig. 257), and within
actual ore bodies or pay shoots.
Capping these
ledges of soft rock are craggy outcrops (PI. LXVIII, Fig. 2) of
silicified and alunitic material which stand out in relief on the
surface because more resistant than the surrounding rocks.
The
ores are almost invariably associated with these, but every sili-
them occur the
ceous knob
is
not underlain by
ore.
The most important
ore bodies are found in dacite, but some

small although rich ones are known in the Milltown andesite
(Fig. 256).
*>
Blackcap
Mtn.
Map
FIG. 257.
showing outcrops of siliceous ledges east of Goldfield,

(After Ransome, U. S. Geol. Surv., Prof. Pap. 66.)
The alteration
Where it is most
of the rock adjoining the fissures
is of three types.
intense the rock has been changed to porous, fine-
grained aggregates consisting essentially of quartz.

the change to a soft, light-colored mass of quartz
second type
while a third,
of propylitic character, consists dn the development of
is
which
Nev.
is
calcite, quartz, chlorite, epidote,
and gypsum.
Most of the ore produced during the first two or three years of the
camp was oxidized in character, but now some of the mines are
working in sulphides.
Ransome's theory is that after the dacite had solidified,
Origin.
but not perhaps entirely cooled, the subjection of the rocks to
stresses
of
unknown
origin developed a
complicated system of
fractures.
Hot waters carrying hydrogen sulphide with some carbon dioxide

and the metallic constituents of the ores rose along these fissures
oxidation of a part of the hydrogen sulphide to sulphuric acid
occurred in the upper parts of the fissure zones or at the surface.
PLATE LXVIII
FIG.
1.
Columbia Mountain,
Goldfield, Nev.,
from the south.
(H. Ries, photo.)]
2.
Ledge outcrop in dacite between the Blue Bell and Commonwealth
mines, Goldfield, Nev. The conspicuous white dump is alunitic material.
The rough knob on sky line near right side of view is Earner Mountain.
FIG.
(After
Ransome, U. S.
Geol.
Sum., Prof. Pap.
66.)
(713)
ECONOMIC GEOLOGY
714
These acid solutions then percolated downward through the

rocks, changing their feldspars to alunite, mingled
with the rising solutions, and precipitated most of their metallic
load as ore, but the original solutions were not everywhere rich
shattered
in metals.
Following this the ledges were fractured, and a second stage of

mineralization occurred, during which further deposition of ore
and in some cases repeated precipitation followed more fracturing.
The ledges are thought to have been formed during the first stage
of deposition, and the softening and alunitization of the rock, as
well as the propylitization, are believed to have occurred at the same
Some good
time.
The
of
ore
was
also deposited then.
Goldfield mining district may be classed as one of the newer ones

For some years the total production of the state had been
Nevada.
small but the discovery of Tonopah in 1900 gave a new impetus to the
search for precious metals in this region, and the finding of the Goldfield
deposits may be rightly reckoned as one of the results.
From the year 1904 to the end of 1914 the Goldfield district has produced
$71,311,552 in gold, 833,442 ounces of silver, and 3,139,780 pounds of copper.
The maximum, total production of about $11,000,OCO was reached in 1910,
The bulk of the
sin.?e which time it has dropped off to about $5,000,000.
ore
is
cyanided.
This district, which was

Tonopah, Nevada (83a-c, 90o, 91).
has
somewhat
in
steadily in production,
1900,
grown
opened up
1
so that its maximum yield in 1913 was about .$9,500,000.
Tonopah (PI. LXX, Fig. 2) lies in the arid desert region of Nevada, and the rocks consist according to Spurr of a somewhat
complex series of flows and intrusives as follows:
8. Basalts and rhyolites.
7.
Siebert tuffs.
6.
Rhyolitic flows.
Midway andesite flow.
5.
3.
West end rhyolite, intrusive just above 3.

Montana breccia, a trachy-alaskite intrusion,
2.
Andesite intrusion between la and
4.
just
above
2.
16.
1. Trachyte consisting of:

a, an upper part, and 6, a Icwer
flowbanded glassy part.
Burgess (83c), differs with Spurr in considering that the rocks
are
all
surface flows.
1
The 1914 production was
slightly lower.
GOLD AND SILVER

The
715
veins belong to three sets or periods as follows: (1) The

formed after the lower trachyte, and before the andesite
chief set,
and silver; (2) formed after the

and before the Midway andesite, and including
intrusion, carrying quartz gold
West end
rhyolite
four subgroups, viz. a, large typically barren quartz veins; 6,

tungsten bearing veins; c, barren, mixed quartz and adularia
iEarlier
j
. \' v'x
Andes.te]
\\
,
Later Andes.te
300
FIG. 258.
Fraction Dacite Brecd
jj
+ + +[
Tonop!lh
I. _L
COO
900
^^
1200
Daoiu
13-5-0-)
IWJ
Oddie Rhyolite V77~,71

l/
Broughfir
p^J^*"
1JOO
Geologic surface map of the producing area of Tonopah.

Burgess, Econ. GeoL, IV: 683, 1909.)
(After
d, productive veins like those of set 1; (3) formed after

the Tonopah rhyolite, and carrying quartz with occasional lead,
veins;
zinc
and copper sulphides.
are complexly faulted, and the movement has

at
different
The primary ore consists of finely
occurred
periods.
divided native gold, argentite, and polybasite in a gangue of
quartz and adularia. In the oxidized ore, which may extend to
The rocks
over 700
ft.,
cerargyrite, embolite
and iodyrite are found.
ECONOMIC GEOLOGY
716
a
.2
"'.a
Kilt
+T
J^P3^-r:*jfy;rnuiia J/
iSi!
ECONOMIC GEOLOGY
71S
In 1914 the total average recovery value per ton of ore pro-
duced was $16.84, most of the ore being treated by cyanidation

with and without concentration.
This lode, of historic interest,
Comstock Lode, Nevada (83).
occurs near Virginia City, in southwestern Nevada (LXIII, Fig.
2), and is a great fissure vein (Fig. 260), about 4 miles long, several
hundred
feet broad,
and branching above, following approximately
Section of Comstock lode. D, diorite; V, vein matter in earlier diabase (Db); H, earlier hornblende andesite; A, augite andesite. (After Becker.)
TIG. 260.
the contact between eruptive rocks, and dipping at an angle of 35

to 45 degrees.
There is abundant evidence of faulting, which
in the
The
middle portion of the vein has amounted to 3000 feet.

is of Tertiary age, and contains silver and gold minerals
lode
in a quartzose gangue.
One
of the peculiar features of the deposit is the extreme

"
bonanzas," some
irregularity of the ore, which occurs in great
of which carried several thousand dollars to the ton.
The fault-
considered to have been quite recent, and the high temperatures encountered in the lower levels of the mine indicate
ing
is
that there is probably a partially cooled mass of igneous rock

at no great depth.
In former years the enormous output of this mine caused Nevada to
be one of the foremost silver producers. It was discovered as early as
1858, and increased until 1877, after which it declined.
Many serious
obstacles were met with in the development of the mine, such that it has
never become a source of much profit in spite of its enormous output. In
1863, at a depth of 3000 feet, the mine was flooded by water of a temperature
GOLD AND SILVER
719
F., due to a break in the clay wall; and to drain it $2,900,000 were
spent in the construction of the Sutro tunnel, which was nearly four miles
long, but by the time it was finished the workings were below its depth.
A second difficulty was the encountering of high temperatures in lower
of 170
workings, those in the drainage tunnel mentioned being 110 to 111 F.

The lode is credited with a total production of over $378,000,000. In recent
years
its
output has been slowly increasing again.
Cripple Creek
(63).
one of this type,

exclusively.
The
This
district,
proper, but in the foothills of this
12,000
which
is
a most important
a producer of ores containing gold almost

region lies about ten miles west of Pike's Peak
is
mountain mass.
ECONOMIC GEOLOGY
720
and
(2)
The two
irregular^replacement bodies, occurring usually in granite.

are not sharply separated.
by the narrowness
All the veins are characterized
and incomplete
filling.
The
of the fissure
lode fissures occur mainly within the

volcanic neck, have a roughly radial
plan, and are usually nearly vertical,
the individual fissures rarely exceed-
But even
ing a half mile in length.
the productive ones may be quite
short, not exceeding a few hundred
and while productive lodes
feet;
may
occur in
haps the
all
schist,
rocks, except per-
they seem to favor
the breccia and granite,
many
fol-
lowing phonolitic or basic dikes.

The lodes generally show a char-
but the
acteristic sheeted structure,

fissures
in
general
are
not
planes, having probably been
fault
formed
about the same time as the intrusions of the basic dikes and caused
ORE/LONG SHEETE.O ZONESection of vein at Cripple
FIG. 262.
Creek, Col.
(After Rickard.)
by compressive
cia
and associated
The
and within the veins
fissures,
which
stresses set
up by a
slight sinking of the solidified brec-
it
ore
intrusives.
occurs
filling
narrow
occurs in shoots of variable
size,
may
develop in any rock.

The ore minerals are mainly tellurides of gold, deposited chiefly
by fissure filling and less often by replacement, with pyrite as a
common
associate; but native gold is rare in the unoxidized ore.

Quartz, fluorite, and dolomite are the most important gangue minerals, and galena, sphalerite, tetrahedrite, stibnite, and molybdenite
are found sparingly.
Oxidation changes the vein to a soft brown, homogeneous mass,
and the tellurides into brown, spongy gold and tellurites, but there
no evidence of secondary enrichment. The ore does not appear to
is
decrease in
of
its
value per ton with depth, though the actual quantity
it is less.
The rocks bordering the veins have undergone some alterawhich is more pronounced in the breccia, and involves a
tion,
change
of the
dark
silicates to carbonates, pyrite,
and
fluorite,
GOLD AND SILVER

and
the
of
feldspars
721
and feldspathoids to
sericite
and adu-
laria.
^10,000-
0,900-
9,Boo-
&J;
.M^-^^;'.-/: .;-, >.
100
200
300 FEET
Vertical section through the Burns shaft, Portland Mine, Cripple

Creek, Col. Shows breccia, contact veins, and dikes.
V, veins; P, phono-
FIG. 263.
lite.
The
line
(After Lindgren
and Ransome, U.
Pap.
have been deposited by hot alkawhich contained the following compounds and
ores are believed to
solutions,
ions either free or in combination: SiO2, CC>2, EkS,
S,
54.)
Cl F, Fe, Sb,
COs, S04,
Mo, V, W, Te, Au, Ag, Cu, Zn, Pb, Ba,
Sr,
Ca,
ECONOMIC GEOLOGY
722
Mg, Na, K.
Some
of these
may have
been leached out of the
volcanics.
The ore is in part smelting ore, which is sent to Fueblo and

Denver for treatment, but the balance, which is considerable, is
treated by the cyanide or the chlorination process.
The Cripple Creek ores as a rule run low in silver as compared with gold,
the average value of the two combined being about $12.00 per ton. Over
95 per cent of the crude ore is treated by the chlorination or cyanide
process at mills in the district or at custom mills near Colorado City, the
rest going to smelters.
The rapid rise of this district
production.
A maximum
is
well
was reached
shown by the following

in
1900,
since
figures of
which the output
has gradually declined.
PRODUCTION ix CRIPPLE CREEK DISTRICT ix 1893-1908 AXD 1914

YEAR
VALUE
PLATE
FIG.
1.
View
of
LXX
Independence Mine and Battle Mountain, Cripple Creek, Col.

(A. J. Harlan, photo.)
FIG. 2.
General view of region around Tonopah, Nev.
(J.
E. Spurr, photo.)
(723)
ECONOMIC GEOLOGY
724
The entire region has not been

studied in detail geologically, but
known with
several quadrangles are
some intimacy and mayibe referred to.

Telluride Quadrangle (65).
In this
quadrangle, whose geologic section is
shown (PI. LXXI and' 'Fig. 264) the
ores occur in veins which are filled

fissures that penetrate all rocks ex-
posed in the area, and were later

even than the rhyolite or the intru-
sions
CQ
M
o
s-
2 2-2
C
-5 3
g
3
^1'*
C
!H
..
.2 .-
!\v-:
diorite
directions
general
noted.
The
c ^" S
the
of
lodes
are
spaced
closely
ore, little of
the
narrow
is
Four
are
fissuring
zones of
with
found outside
fissures
which
zone.
stocks.
of
filled
The
veins vary in
3 feet, but
about
width, averaging
the ore usually forms a narrow strip
following one side or the other, and
of
rarely filling the entire zone.

The veins also vary somewhat in
regularity, according to the
kind of rock through which they
pass, being best developed in the
their
andesite.
The
Faulting
is
rare.
ore minerals are galena, frei-
(argentiferous gray copper),
bergite
polybasite, proustite, stephanite,

W B
o -v
^ o
(V
w.
*~S
pyrite
also a
and
perhaps other silver sulphides, with

more or less gold, which may be in
and chalcopyrite.
number
of metallic
There are
and non-
^l^
metallic gangue minerals, including

sphalerite, zinc blende, mispickel,
o
^
5 g M
magnetite, native copper, quartz, cal-
.%
-r.
ft
siderite, rhodochrosite, dolomite, fluorite, barite sericite, biotite,

cite,
chlorite,
amphibole, apatite, garnet,
orthoclase, picotite,
and
kaolinite.
Potos'i rhyoRte
series
Potos'i Vol carries
(1300 '+5
(2,000')
Intermediate
series.Andesite
&
Silverton series
Andesites
(230'- 2,500')
rhyollte
(1300')
San Juan
series,
Andesite debris
San Juan
02,000')
Andesita
tuffs
(3,000.0
San
Shales and*
sandstone*
(
Mj'g^rel
conglomerate
,(200- 1 ,000*1
1,600'+
Msncos
shale
(2, ooo'+;
Sandstones
and shales
(700'- 1.000')
/ Dakota
sandstone
((1
25'- 175')
McEfmo
Permian
sandstones
sandstones
shales
etc.
(600'-
9000
2,000'+)
La Plata
sandstone
Pennsylvanian
sandstones
shales and
m
'\
Dolores
limestones
1,2 00'- 2,000')
I (100'- 175')
'A.?-
sandstones
conglomerates
(1,550'+)
^Llmetone(1750
Quartzlte and
slate
(
PLATE
LXXI
8,000'+>
General columnar section of A, Ouray quadrangle; B, Telluride

U = unconformity. (U. S. Geol. Surv.)
quadrangle.
(725)
ECONOMIC GEOLOGY
726
The greater number of veins have been found in the granular

rocks of the stocks along the central, east, and west portions
of the area, and in the heavy andesitic breccia, tuff, and agglomerate of the
San Juan formation (PL LXXI),
Rb
Not Classified
1
\\
as to
Geologic
j"j
d
|
<
Age
3
a
best
developed
San Miguel
Conglomerate
2~
Geologic map of Telluride district, Col., showing outcrop of more

important veins. (After Winslow, Amcr. Inst. Min. Engrs, Trans. XXIX.)
FIG. 265.
in the northern half of the area.
This
last
horizon has been the
most productive.
ore appears to have been deposited from ascending hot-water
solutions which penetrated all open spaces in the fissured zones.
The
Ransome explains it as follows Surface waters percolating downward dissolve alkalies from the igneous rocks as sulphides. These
alkalies as they become hotter on approaching the magma become
charged with sulphidic and carbonic acids derived from volcanic
:
GOLD AND SILVER
727
sources, thus
becoming solvents for the metals, and silica, lime,

which they gathered from the more basic portions of the
magma. These solutions then brought metals and silicates and
etc.,
deposited them higher up.

The metals were deposited in the fissures, while the penetration of the wall rocks by the alkaline solutions containing sulphuric acid changed the iron in the ferromagnesian silicates,
and the potash went toward the formation of sericite. Carbonates were deposited on the walls, due to the action of water on
lime feldspars. Silica was set free and removed mostly from
the walls. Gold was carried into the walls to some extent.
This quadrangle lies east of the

formations are the Archa3an schists and
Silverton Quadrangle (67).
The
Telluride.
oldest
gneisses, overlain
quartzites, and these in turn by

and
Carboniferous
Cambrian, Devonian,
sediments, the whole
a
thick
series
of
volcanics
similar to those
being capped by
Tertiary
of the Telluride quadrangle, but separated from the top of the Car-
boniferous
by Algonkian
A number
by a conglomerate.
of unconformities are
present in different parts of the series.
The ore deposits are of three types, viz. (1) lodes, which include
most of the now productive deposits; (2) stocks or masses, which
include most of the ore bodies formerly worked on Red Mountain;
(3) metasomatic replacements, including a few deposits found in
:
limestones or rhyolite.
The lodes, which are widely distributed and vary in size and degree of mineralization, may occur in all the rocks from the pre-Cam-
brian schists to the latest monzonitic intrusions, cutting the Tertiary volcanics, but the greater number are found in the San Juan
tuff
and Silverton volcanic
Moreover, the gold and
series.
silver
are not uniformly distributed in the quadrangle.
The most conspicuous
fissuring is northeast-southwest,
with dips
75, and faulting noticeable in but a few lodes.

were formed substantially at the same time, and prob-
usually of about
The
fissures
ably in late Tertiary.

Most of the lodes are simple fissure veins, showing bands of
gangue and ore confined between definite walls, while the width
of the workable vein varies
The
wall rock
is
from a few inches up to 10 or 12
not usually
much
replacement deposits.
The ore minerals are tetrahedrite, very common,
As and Sb
enargite,
common
in
feet.
altered except in the rhyolite
may
carry both
chalco;
Red Mountain range
ECONOMIC GEOLOGY
728
pyrite,
common and sometimes auriferous galena, very important

sphalerite, common and accompanies galena, and
;
and widespread
several silver sulphides, not very abundant.
Both native gold and
silver also occur.
The gangue minerals
are quartz, barite, calcite, dolomite, rho-
dochrosite, kaolinite, pyrite, etc.

The ores were probably deposited
by ascending waters, but their

exact source or depth of origin is not known.
Metasomatism of wall rocks differs in different parts of the quadrangle.
Thus, for example, in the Silver Lake Basin, feldspar is
and quartz augite, to calcite and chlorite;
and rutile. Sericite and quartz are common
close to the vein.
This shows a propylitic type of alteration.
The ore deposits, which may be reOuray Quadrangle (62).
garded as an extension of those of the Silverton quadrangle area, are
all located near the town of Ouray, and while the district contains
altered to sericite, calcite,
and
biotite, to sericite
but few productive mines, they are of great scientific interest. A

few are found in disturbed rocks near dikes or sheets of porphyry,
but most of them occur in but slightly disturbed formations. All
owe
form of the ore

body depending, however, on the openness of the fissure and kind
their existence to the presence of fissures, the
The three following types are recognized (1) fissure

(2)
great vertical extent
replacements in quartzite ;
Where the fissures followed by the
(3) replacements in limestone.
ore-bearing solutions were open, a simple, banded, filled vein was
of wall rock.
veins of
but where narrow, the solutions spread out laterally in

the wall rock, replacing the same, and the process reached a maxiin the more soluble beds.
formed;
mum
The fissures show great vertical extent,

several types are as follows
Fissure Veins.
(a) This type, which
includes silver-bearing veins in fissures
and the characters
of the
McElmo
the most
important,
slight
Mancos
(PL LXXI). Ore more abundant and
of higher
be
or
absent
of
low
may
grade in
Tetrahedrite and argentiferous galena, with quartz and
grade in quartzite walls,

shales.
of
displacement,
shale, to the sandstones underlying
distributed from the
the
is
but
gangue as common vein minerals. (6) Gold-bearing veins

representing a group of mineralized, highly inclined, sheeted
zones in dikes of quartz-bearing monzonite porphyry. The chief
minerals are auriferous pyrite, and chalcopyrite in a gangue of
country rock and clay.
barite
GOLD AND SILVER
729
Irregular bodies in the
Quartzite Replacements.
stones, with gold and subordinate silver.

Limestone Replacements.
Broad flat
ore
Dakota sandadjoining
bodies,
with numerous small vertical
fissure veins, or associated
Silver predominates in some, with a barite, silica gangue,
fissures.
and gold
The former are associated

with a magnetite gangue in others.
fissure veins which penetrate limestone.
with the
All the deposits of the Ouray district appear to belong to a single

period of mineralization, and are of recent formation, being later
than the latest igneous intrusions.
Among the other occurrences of this group

be mentioned the gold-quartz veins in rhyolite of the De
Lamar mine in Idaho (72); the Bullfrog district of Nevada (87),
Other Occurrences.
may
At
and the National mining district in the same state (85c).
the last named, the fissures in Tertiary lavas carry gold and
some silver in a quartz gangue, together with pyrite, blende,
a,nd always more or less stibnite, while one contains cinnabar.
One vein had a remarkable shoot of pale gold which in four years
yielded nearly $4,000,000.
Another interesting occurrence
is
in the
Republic
district of
Washington whose beautifully crustified quartz veins carry both

gold and selenium (I19a), the only other deposit of this type
1
being the Redjang Lebong of Sumatra.
Foreign Deposits.
sulvania, there are a
Hungary.
number
In eastern Hungary
of gold
and
including Trans-
silver deposits, associated
Tertiary eruptives chiefly andesites and dacites.
Those
with
Hungary include
Transylvania, Brad (the
in
Nagybanya, Felsobanya, and Kapnik, and in

most important), Nagyag, etc. At Nagyag the gold occurs as tellurides,
while in the other Transylvanian districts, it is native. Accompanying it
are silver-ore minerals, as well as some pyrite, galena, blende, antimony,
and tetrahedrite, in a gangue chiefly of quartz, but often containing as well
manganese carbonate and silicate. The veins, which may be a meter thick,
are usually fissure fillings, and the lodes may be 30 to 60 feet across. Propylitic
alteration of the wall rocks
New
The
is
common.
the Hauraki region known in later

years for the output of the famous Waihi mine, contain small veins of
massive or comby quartz with rich pockets of gold in propylitized Tertiary andesites and dacites in the northern part of the district, while the
Zealand.
veins
of
southern part the veins are of great width, with the ore shoots uniform
continuous. 3
and
2
3
Beck, Erzlagerstatten, I: 488; Truscott, Min. Mag., VI:~355, 1912.

Vogt, Krusch und Beyschlag, Lagerstatten, II: 31, 1912.
Finlayson, Min. Mag., II: 281, 1910; also Econ. Geol., IV: 632, 1909.
ECONOMIC GEOLOGY
730
Mexico contains a number of well-known representatives of this group,

located especially in the eastern Sierra Madre, which, though usually occurring
in Tertiary eruptives, sometimes cut sediments.
Among these localities
l
should be mentioned Parral, Guanajuato, Real del Monte, Zacatecas, and

Pachuca. Silver predominates, the ore minerals, including pyrargyrite,
and polybasite, accompanied by tetrahedrite, galena,

gangue chiefly of quartz. The greater part of the Mexican
gold production comes from the mines of El Oro.
argentite, stephanite,
and blende
in a
Gold Placers
These form an important source of supply of gold, together
little silver, and, although widely distributed, become
prominent chiefly in those areas in which auriferous quartz veins
are abundant.
So, while in North America they are found in
many parts of the Cordilleran region, the Black Hills, and southern Appalachian region cf the United States, their greatest
development is in the Pacific Coast belt from California to Alaska,
and in the Yukon district of Canada. Others of importance are
found in South America and Australia.
with a
Most
of the gold placers are of Tertiary or
but older ones are also known
Quaternary age,
(p. 685).
Placer deposits may be formed in difTypes of Placers.

ferent ways, as follows:
Eluvial placers.
These originate in those regions where goldbearing rocks are subjected to deep weathering, during which the
gold
may
down
undergo more or
some
less concentration,
and
also migrate
The gold
grains are usually angular,

as they have not been exposed to the wearing action of streams.
In the United States, this type is known in the southern Appaslope to
lachians, but
Dry
it
extent.
has also been found in Brazil, the Guianas, etc.

In regions of aridity, where
cr Eolian placers (36, 36a)
the rocks are disintegrated, the lighter particles may be blown

away while the heavier ones, including gold, remain behind.
Stream placers (42, 47)
These represent the most important
.
and widespread type.
As the products
of rock
decay are washed
down
the slopes into streams, the fine clayey material is carried

a long distance, but the heavier particles, including gold, settle
rapidly, the gold,
1
Vogt, Krusch
Inst.
on account of
und Beyschlag,
Min. Engrs., Trans.
higher gravity, usually col-
Lagerstatten, II:
XXXII:
(Pachuca); Blake, Ibid., p. 216, 1902.

357, 1909.
(Silver Mines.)
XXXIX:
its
66, 1912.
Aguilera,
Amer.
Ordonez, Ibid., p. 224, 1902.

(Guanajuato); Bordeaux, A. F. J. f Ibid.,
497,
1902;
GOLD AND SILVER
731
lecting in the lower part of the deposit, or even in crevices of the

bed rock. Even if it does not do so at once, agitation of the
sediment may cause it to settle deeper, or even slowly migrate
down stream
as the sediment shifts.

Coarse gold carried down
from
streams
will
settle
with coarse sediment
higher
levels,
by
in the upper part of a stream's course, but very fine flake gold
may be transported some distance farther down stream.
In some regions thick gold-bearing gravel deposits have by
downward cutting of the streams due to elevation of the land,

been deeply trenched, leaving the uneroded remnants as benches
along the valley slopes. Cases of this sort are found on the
western slope of the Sierra Nevada in California, on Anvil Creek
in the
Nome
district of Alaska,
and
in the
Klondike
district of
the Yukon.
In some instances stream placers

under other barren gravels, or lava
may have become

flows.
buried
(Victoria and some

instances has to be
The gold in such

California deposits.)
recovered by underground methods.
These are formed by the sorting action of
Marine placers.
the waves along coasts where auriferous gravels or sands are
exposed. They are known in California and Oregon, but the
best examples are those of Cape Nome, Alaska.
Size of the Placer Gold.
Gold occurs
in placers in the
form
The nuggets represent the

of nuggets, flakes or dust-like grains.
of
the
some
and
finding
largest pieces,
very large ones has been
recorded from time to time in different parts of the world. Two
"
Welcome
large nuggets are recorded from Victoria: one the
"
Stranger," weighing 2280 ounces; and the other the Welcome

Nugget," weighing 2166 ounces. Most of the placer gold obtained
and some may be very
fine.
Lindgren states
without trouble divisible
into 2000 parts, each of which can be readily recognized in a pan.
Placer deposits may contain a numAssociated Minerals.
is
in small grains,
that a piece of gold worth one cent
is
ber of heavy minerals, which settle out with the gold in the sluice
boxes.
These include magnetite, ilmenite, (black sand), garnet,
sand), monazite (yellow sand), cassitefite,
Pyrite or marcasite may form in the gravels.
California (42, 47).
These have been derived from
zircon
(white
and
platinum.
the
wearing down of the Sierras, and are found in those valleys leading off the drainage from the mountains.
Many were formed
during the Tertiary period, when the Sierras were subjected to a
ECONOMIC GEOLOGY
732
long-continued denudation, while violent volcanic outbursts at

the close of the Tertiary have often covered the gravels and protected them from subsequent erosion.
These lava cappings are
at times 150 to 200 feet thick, as in Table Mountain,
Tuolumne
County.
Many of
others
lie
the gravel deposits are on lines of former drainage, while

still occupied by streams.
Some show but one
in channels
streak of gold, while in others

may be several, some of
there
which are on rock benches of

the valley bottom (Fig. 266).
During the early days of gold

mining in California the gravels
at lower levels and in the valley
bottoms were worked, but as
Generalized section of old
a, volplacer, with technical terms,
bench
canic cap
c,
6, upper lead
gravel d, channel gravel.
(After R. E.
FIG.
266.
these
became exhausted, those

up the slopes or hills
farther
were sought.
In the earlier operations the
Browne.)
gravels were washed entirely by
hand, either with a pan or rocker, and this plan is even now followed
by small miners and prospectors but mining on a larger scale is
;
on by one of three methods, viz. drift mining, hydraulic

mining, and dredging.
Drift mining is employed in the case of gravel deposits covered
by a lava cap, a tunnel being run in to the paying portion of the
bed and the auriferous gravel carried out and washed.
In hydraulic mining (PL LXXII, Fig. 1), a stream is directed
against the bank of gravel and the whole washed down into a
rock ditch lined with tree sections, or into a wooden trough with
The gold, being heavy,
crosspieces or riffles on the bottom.
settles quickly and is caught in the troughs or ditches, while the
other materials are carried off and discharged into some neighboring stream. Mercury is sometimes put behind the riffles to
carried
aid in catching the gold.

is used to wash down the gravel deposits is
brought a long distance, sometimes many miles, and at
great expense, bridging valleys, passing through tunnels, and
even crossing divides, this being done to obtain a large enough
supply as well as a sufficient head of water.
The water which
often
Owing
to the great
amount of
debris which
was swept down into
PLATE LXXII
FIG.
1.
Hydraulic mining of auriferous gravel.

is for
FIG.
2.
The
sluice
box in foreground
catching the gold.
An
Alaskan placer deposit.

(733)
ECONOMIC GEOLOGY
734
the lowlands, a protest was raised by the farmers dwelling there,

who claimed that their farms were being ruined and it soon became
a question which should survive, the farmer or the miner, for in
;
places the gravels
and sand from the washings choked up streams
to a depth of 70 or 80 feet.
The question was
settled in 1884 in favor of the farmer by an injunction, issued by the
and accumulated
United States Circuit Court, which caused many of the hydraulic

mines to suspend operations and at a later date this was extended
;
by state
Owing to
adverse to the hydraulic mining industry.

this setback, hydraulic mining fell to a comparatively
legislation,
unimportant place in the gold-producing industry of California,

while at the same time quartz mining increased.
The passage of the Caminetti law now permits hydraulic mining,
but requires that a
dam
shall
be constructed across the stream to
catch the tailings. This resulted in a revival of the industry, but

even so, the placer mining industry is seriously hindered by the
present laws governing
it.
from the river with some

Dredging
form of dredge. The method, which was first practiced in New
Zealand, has been introduced with great success into California,
especially on the Feather River, near Oroville, and its use has spread
to other parts of the Cordilleran region and Alaska. The gravel
when taken from the river is discharged onto a screen, which
separates the coarse stones, and the finer particles pass over amalgamated plates, tables with riffles, and then over felt.
Placer gold is also w orked in Idaho, Montana, Oregon, New
consists in taking the gravel
Mexico, and Colorado, all of the deposits except those of the last
two states having been derived mostly from Mesozoic veins.
Gold also occurs in beach sand of certain portions of the Pacific
coast of Washington (119), and placer mining has been carried
on since 1894; but the supply of gold, which is obtained from
Pleistocene sands
and
gravels,
is
small.
In arid regions, where the gold-bearing sands are largely the

product of disintegration, and water for washing out the metal is
wanting, a system known as dry blowing is sometimes resorted to.

The placer deposits have been found in many
Alaska.
parts of Alaska, but the two regions which have yielded the
largest amount are the Yukon region (24, 33) and the Seward
Peninsula
(24, 30),
the latter being
now
the
first.
Gold was discovered in the Forty Mile district of the Yukon

in 1886, and caused a stampede for this region; but the deposits
GOLD AND SILVER
735
Klondike did not become known until 1896, and their discovery was followed by a rush of gold seekers that eclipsed all
previous ones. Indeed, it is said that by 1898 over 40,000 people
of the
were camped out in the vicinity of the present site of Dawson.

The Klondike region proper is situated on the eastern side of
the Yukon River, and the richest deposits found have been on
the Canadian side of the boundary. The gold has co'lected either
at the bottom of the gravel in the smaller streams tributary to
the Yukon, or else in gravels on the valley sides, this latter occurrence being known as bench gravel. The metal is supposed to
have been derived from the quartz veins found in the Birch Creek,
Forty Mile, and Rampart series of metamorphic rocks lying to
the east. Up to the end of 1902 the total production of the
Klondike is stated to have been $80,000,000. The annual output
has, however, decreased, and mining in that region has settled
down to a more permanent basis. Gravels running under 50
cents per cubic yard cannot be worked at a profit, even by
dredging, because the difficulties and expenses of mining in such
a region are great, and form an interesting comparison with
conditions in California, where gravel carrying 25 cents per yard
is considered good, while that running as low as 5 cents per yard
can be worked as a dredge proposition (26). 1
Since the discovery of the rich gold gravels on the Yukon,
auriferous gravels have been developed in many other parts of
Alaska, where they are being more or less actively worked (Fig.
241), but of these various finds those in the Seward Peninsula,
which is now the largest producer, have been the most important.
The
first
of the
localities
discovered in the last-mentioned
Cape Nome (30, 31), which for a time proved to be a

second Klondike. The gold was discovered here on Anvil Creek,
and the following year in the beach sands where Nome now stands.
region was
These discoveries caused another northward stampede, which

resulted in the rapid exhaustion of the beach sands; but other
deposits were found farther inland near Nome, as well as the
other localities on the Seward Peninsula. Some quartz veins are
also worked.
Up to the end of 1914 the Seward Peninsula had
produced $68,642,700 in gold, and in 1906 its production is given
In the
as $7,500,000, but by 1914 it had dropped to $2,733,000.
Fairbanks district (29), which is another important placer area,
and lies in central Alaska (Fig. 241), there is a remarkable accu1
See also U.
S.
Geol. Surv., Bull. 263.
ECONOMIC GEOLOGY
736
mulation of unconsolidated material overlying the bed rock,

which seems to have been deposited in an area where glaciation
was absent, but fluviatile conditions predominated.
An interesting feature of these deposits is their remarkable

thickness, and their depth of consolidation by ice, over 300 feet,
as revealed by mining operations.
The unconsolidated material
includes slide rock, muck, sand, silt, clay, barren gravels, and the
These productive gravels,
gravels in which the gold is found.
so far as discovered, are a thin layer next to bed rock,
and the
value of the gold recovered has ranged from less than $1 to $8 or

more per square foot of bed rock surface. The present activities
are supported
foot,
and
deposits of $1 or less per square

deep placers yielding as little as 40 cents per
by low-grade
in 1914
square foot were worked by drifting.
The
Iditarod district, which produced about
of gold in 1914, obtained
mostly by dredging,
2,000,000 worth
the third large
is
producer.
A number
of smaller districts
add to the
total supply of the
territory.
Yukon Territory (133)

The Klondike gold fields are situated
on the east side of the Yukon River at its confluence with the
Klondike, and cover an area of about 200 square miles. The district is a part of a dissected upland, and a second uplift in recent
.
times has caused the streams to deepen their valleys, but portions
of the old valley bottoms, covered with heavy accumulations of
still remain as benches on the valley sides at many points.
to the unglaciated character of the region, the rocks are
deeply weathered. The surface materials are permanently
frozen.
gravel,
Owing
The
auriferous gravels occur under the following conditions:

Low-level creek gravels, 4 to 10 feet deep, resting on bed
rock, and covered by 2 to 30 feet more of black frozen muck.
(1)
These are the most important; (2) gulch gravels, found in the
upper portions of the main creek valleys, and small tributary
valleys; (3) gravels on rock terraces, formed during the deepening of the valleys, and representing portions of an old valley
bottom; (4) high-level gravels, representing ancient creek deposits, accumulated when the river flowed several hundred feet
"
White Channel " gravels,
higher than it does now. Of these the
so called because of their white or light-gray color, are important, and represent the oldest stream deposits of the district.
GOLD AND SILVER
737
in thickness from a few to 150 feet, and are second

commercial importance to the present creek gravels.
The Klondike gold varies in fineness, due to its being in
The lowest grade has a value
all cases alloyed with silver.
of about $12.50 an ounce, but some has exceeded $17.50 an
They range
in
ounce.
This colony contains a remarkable series of buried channels,
The gold occurs in gravels of Tertiary streams, which,
following a depression, became covered by thick beds of sand and clay,
and these in turn by basalt flows of several hundred feet thickness. The
gold was first discovered in the upper part of the former stream courses
and then followed down under the basalt.
Russia.
Gold gravels, which Purington claims belong to one of the
Victoria. 1
called
"deep leads."
greatest placer fields of the world, are being developed

in Siberia. 2
South Africa. 3
The
on the Lena River,
auriferous conglomerates of the Johannesburg dis-
of the Transvaal, S. Afr., are among the most remarkable known.

They are of apparently simple structure, yet very puzzling as to origin.
The section involves a basal series of crystalline schists intruded by granites,
trict
on whose eroded surface rests the Upper and Lower Witwatersrand system
and conglomerates, aggregating 19,000 feet in thickness, and overlain in turn by the Ventersdorp system of volcanics.
The Witwatersrand, which is probably of Cambrian or pre-Cambrian age,
forms a syncline with Johannesburg on its north side. The series has been
of slates, quartzites,
and also cut by diabase dikes, and while auriferous conglomerates

are found at several different horizons, the most productive ones are in the
faulted
upper part.
The ore consists of pebbles mostly of quartz, in a sandy matrix, with

abundant pyrite in the cement. The gold, which occurs in the cement
but not in the pebbles, is closely connected with the pyrite. Some of the
It is not yet definitely settled whether
gold has migrated and recrystallized.
the auriferous conglomerate represents an ancient placer, or whether the
gold and pyrite are epigenetic and introduced after the dikes, and for the
detailed arguments reference should be made to the articles referred to.
It is provisionally placed
with the placer deposits.
Uses of Gold.
Gold is chiefly used for coinage, ornaments,
and ornamental utensils. It is employed to a considerable extent
in dentistry and in an alloy for the better class of gilding.
Its value for use in the arts depends on its brightness, freedom
from tarnish, and its ductility and malleability, which permit it
1
Lindgren, Min. Mag. XI: 33, 1905, and Eng. and Min. Jour., Feb.
16, 1905.
Min. Mag. XII: 341, 1915.

'Hatch, Types of Ore Deposits, San Francisco, 1911; Gregory, Econ. Geol.,
IV: 118, 1909; Hatch, Min. and Sci. Pr., GUI: 98 and 132, 1911; Horwood,
Min. and Sci. Pr., CVII: 563, etc., 1913; Schwarz, Min. Mag., XIII: 223, 1915.
ECONOMIC GEOLOGY
738
to be easily worked.
As pure 24-carat gold is too soft for use,

amount of some other metal, such as
alloyed with a small

copper, to gain hardness.
it is
This metal was formerly of much importance

much less so now. It is, however, widely
employed in the arts for making jewelry and utensils such as
Its salts are of more or less value in medicine and
tableware.
Uses
of Silver.
for coinage, but
in
is
Its brightness and white color are valuable

the metal is used, but, unlike gold, it tarnishes
There are
readily when exposed to sulphurous gases.
photography.
properties
when
somewhat
a number of
alloys of silver, those with gold
ively, being of
and copper, respect-
importance.
Production of Gold and Silver.
The
total
production of
gold and silver for the United States and other countries
on the following pages.
is
given
PRODUCTION OF GOLD AND SILVER IN THE UNITED STATES, 1860 TO 1914

GOLD
YEAR
SILVER
GOLD AND SILVER
739
The recovered output of gold and silver in the United States

from domestic ores and gravels in 1914 is given below.
APPROXIMATE DISTRIBUTION, BY PRODUCING STATES AND TERRITORIES, OP
THE PRODUCTION OF GOLD AND SILVER IN THE UNITED STATES FOR
THE CALENDAR YEAR 1914, IN FINE OUNCES 1
STATE OB TERRITORY.
ECONOMIC GEOLOGY
740
K
w ^
^ a
S g
i
*
g I
gfe
2 g
w
S"
^
5
fH
02
of
>i
s w
5 o
p Z<
6
H
CD
C k>
5"B
fS
m f
Z g
a
u
*#
SK
^ 5
o g
^
s
o H
P &
O
t>
fi
O g
5
Z
AH
P
o
GO
GOLD AND SILVER
741
ECONOMIC GEOLOGY
742
PERCENTAGE OF OUTPUT OF GOLD AND SILVER BY PROCESSES IN THE UNITED

STATES IN 1912, 1913, AND 1914
PRODUCTION BY
GOLD AND SILVER
743
possible only in the case of placers, which are found chiefly in California
These are estimated to contain perhaps $1,000,000,000 of
gold in reserve, and the output from this source will probably not decrease
and Alaska.
some time. The gold derived from copper ores is not large
($4,800,000 in 1908), but is a stable and increasing quantity, likely to
That derived from lead ores is much less, and
last for 25 years at least.
for
a slow decrease
may
be expected.
The quartzose ores form an important source, likely to continue active

and strong producers. The United States gold production is not likely
to rise above $110,000,000, nor is it likely to sink below $60,000,000 for
a long time. Owing to the low price of silver, a number of mines producing ore of this metal have shut down, but the increasing amount supplied
as a by-product from lead and copper ores has kept the output steady.
The present supply is regarded as assured as long as the mining of lead
and copper ores, as well as quartzose gold ores, continues on the present
scale.
PRODUCTION OF GOLD AND SILVER IN CANADA BY PROVINCES IN 1914
PROVINCE
ECONOMIC GEOLOGY
744
PRODUCTION OF GOLD IN THE WORLD, 1860-1914

[The annual production from 1860 to 1872 is obtained from 5-year periods
compiled by Dr. Adolph Soetbeer. From 1872 to 1912, inclusive, the estimates are those of the Bureau of the Mint. The figures for 1913 and 1914
are in part final and in part estimates of the Survey from best available
information, and are subject to revision.]
YEAR
VALUE
YEAR
I860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
$134,083,000
122,989,000
122,989,000
122,989,000
122,989,000
122,989,000
129,614,000
129,614,000
129,614,000
129,614,000
129,614,000
115,577,000
115,577,000
96,200,000
90,750,000
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1871
1872
1873
1874
GOLD PRODUCTION
VALUE
YEAR
VALUE
YEAR
97,500,000
103,700,000
113,947,200
119,092,800
108,778,800
106,436,800
103,023,100
101,996,600
95,392,000
101,729,600
108,435,600
106,163,900
105,774,900
110,196,900
123,489,200
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
$118,848,700
130,650,000
146,651,500
157,494,800
181,175,600
198,763,600
202,251,600
236,083,700
286,879,700
306,724,100
254,576,300
260,992,900
296,737,600
327,702,700
347,377,200
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
$380,288,700
402,503,000
412,966,600
442,476,900
454,059,100
455,239,100
461,939,700
466,136,100
454,942,211
453,000,000
Total
$11,257,320,811
IN THE
WORLD
IN 1913
COUNTRY
VALUE
AND 1914 BY COUNTRIES

1914
1913
North America:
United States
Canada
Mexico
Cuba
....
....
Africa
Australasia
'$94,531,800
15,925,044
3
18,000,000
$88,884,400
16,216,131
18,250,000
3
24,600
205,875,000
53,038,090
Europe:
Russia and Finland
Austria-Hungary
.
Germany
Norway
....
....
and
Spain
Portugal
Turkey ....
France ....
Great Britain
Servia
....
South America:
624.578,575
4
2,180,414
3
60,000
Sweden
201,000,000
549,386,180
26,750,000
1,500,000
36,630
30,572
2,500
6 500
1,946,600
17,860
3
250,000
4
Italy
1,000,000
Argentina
100,000
Bolivia and Chile
100,000
800,000
3,000,000
7289,133
3,009,786
4
444,800
3
Colombia
Ecuador
Brazil
....
....
Venezuela
.
3,000,000
Guiana:
British
Dutch
French
Peru
Uruguay
Central America
Asia:
....
....
Japan
China
Indo-China
Chosen (Korea)
Siam
India, British
East Indies, British
East Indies, Dutch
Total
470,433
3,050,600
s
492,200
s
111,000
3,000,000
1,353,368
4
'
4,470,723
s
3,658,900
s
70,000
4
3,281,333
s
56,500
11,152,463
s
1,352,000
83,387,100
454,942,211
1,250,000
3
500,000
3,000,000
3
500,000
3,500,000
4,476,500
3,800,000
3,750,000
511,388,870
4,750,000
4
10
453,000,000
3
Min. World, Feb. 6, 1915;
estimated; 4 Director Mint. Ann. Rep.,
Dec. 5, 1914; 8 Min.
1914; s Mi n Mag., Apr., 1915; * Min. Mag., 1914; 7 Min. Jour.,
9 Min. and Sci.
10
includes estimates for countries not
Indus., 1914;
Pr., May, 8, 1915;
'Official;
specified
GOLD AND SILVER
745
REFERENCES ON GOLD AND SILVER

1. Blake, Amer. Inst. Min. Engrs., Trans. XXVI:
290, 1897.
la. Brokaw, Jour. Geol., XVIII: 321, 1910.
(Gold in igneous rocks.)
2. Crane, Gold and Silver, New
(Solution of gold in weathering.)
York, 1908. 3. Cumenge and Robellaz, L'Or dans la Nature, Paris,
1898.
4. Curie, The Gold Mines of the World, London, 1902.
5. De
Launay, The World's Gold, Its Geology, Extraction, and Political
GENERAL.
Economy, Translation,
Trans.
lodes.)
7.
3,
1912.
New
XXVII:
Emmons, W.
Engrs.,
(Rel'n of
Indus., VI:
Dec. 1S07.
York, 1908.
564,
1898.
6.
Don, Amer.
(Genesis of
certain
Inst.
Min.
auriferous
H., Amer. Inst. Min. Engrs., Trans. XLII:

manganese to gold sec'y enrich't.) 8. Kemp, Min.
9. Keyes, Econ.
Geol.,
Lenher, Econ. Geol., IV: 544,
11. Lenher, Econ. Geol., VII: 744, 1912.
1909.
(Tellurides.)
(Trans12. Lincoln, Econ. Geol., VI:
p'n and depos'n of gold in nature.)
13. Lindgren,
(Certain natural associations of gold.)
247, 1911.
U.
295,
1898.
(Telluride
(Cerargyritic ores.)
ores.)
10.
(Conservation of gold,
silver, re-
13a. Lindgren, Amer. Inst.

(Gold and silver of N. Amer.
Min. Engrs., Bull. 112: 721,

1916.
and S. Amer.) 14. MacLaren,
Gold, Its Geological Occurrence and Geographical Distribution, London,
1909.
15. Merrill, Amer. Jour. ScL, I: 309, 1896.
(Gold in granite.)
15a. Palmer and Bastin, Econ. Geol., VIII:
(Metallic
140, 1913.
minerals as precipitants of gold and silver.)
16. Rickard, Min. and
Sci. Pr., LXXVII: 81 and 105, 1898.
(Minerals accompanying gold.)
17. Rickard, Min. and Sci. Pr., Oct. 20, 1906.
(Geological distribution
of world's gold.)
17a. Sharwood, Econ. Geol., VI: 22, 1911.
(Tellurium bearing gold ores.) 18. Spurr, Eng. and Min. Jour., LXXVI:
sources.)
(Gold in diorite.) 19. Spuft, Ibid., LXXVII: 198, 1904.

(Native gold in original metamorphic gneisses.) 20. Stokes, Econ.
Geol., I: 644, 1906.
(Experiments on solution and transportation of
gold and silver.) 21. Weed, Amer. Inst. Min. Engrs., Trans. XXX:
424, 1901.
(Enrich't, gold and silver veins.)
Alabama: 22. Brewer, Ala. Geol. Surv., Bull. 5, 1896. 23.
ARE AL.
Alaska: 24. Brooks and
Phillips, Ala. Geol. Surv., Bull. 3, 1892.
others, U. S. Geol. Surv., Bull. 259: 1905, also later ones issued annually,
25. Moffat, U. S. Geol. Surv., Bull. 314:
descriptive of Alaska resources.
500, 1903.
Eng. and Min. Jour., LXXVI: 807,

U. S. Geol. Surv., Bull. 375, 1909.
(Forty Mile region.) 28. Prindle, U. S. Geol. Surv., Bull. 345: 179.
(Yukon-Tanana region.) 29. Prindle and Katz. U. S. Geol. Surv.,
Bull. 379: 181, 1909.
(Fairbanks placers.) 30. Schrader and Brooks,
Amer. Inst. Min. Engrs., Trans. XXX: 236, 1901. (Cape Nome.)
31. Smith, U. S. Geol. Surv., Bull. 379, 1909.
(Nome and vicinity.)
32. Spencer, U. S. Geol. Surv., Bull. 287, 1906.
(Juneau district.)
33. Spurr, U. S. Geol. Surv., 18th Ann. Rept., Ill: 101, 1898.
(Yukon
Arizona: 34. Bancroft, U. S. Geol. Surv., Bull. 451, 1911.
district.)
35. Blandy, Amer. Inst. Min. Engrs., Trans.
(N. Yuma County.)
XI: 286, 1883. (Prescott district.) 36. Carter, Min. and Sci. Pr.,
CV: 166, 1912. (Placers.) 36a. Heikes and Yale, U. S. Geol. Surv.,
126.
(Nome
852, 1903.
region.)
(General.)
26. Penrose,
27. Prindle,
ECONOMIC GEOLOGY
746
Min. Res., 1912.
I:
255, 1913.
(Dry placers.) 37. Kellogg, Econ.
(Cochise County.) 38. Schrader, U. S. Geol.
651, 1906.
(Cerbat Range, Black Mts., Grand Wash Cliffs.)
Surv., Bull. 397, 1909.
39. Schrader, U. S. Geol. Surv., Bull. 582: 92, 1915.
(Santa Rita and
I:
Geol.,
39a. Jones, U. S. Geol. Surv., Bull. 620: 45, 1915.

California:
40. Bateson, Amer.
Inst.
Min. Engrs.,
Patagonia Mts.)
(Quartzite.)
Trans.
Inst.
XXXVII:
1907.
160,
Min. Engrs.,
(Mojave
41.
district.)
XXXVIII:
Trans.
Brown, Amer.
1908.
(Vein systems,
42. Browne, Calif. State Min. Bur., 10th Ann. Rept.:
Bodie, Calif.)
435.
(River gravels.) 43. Diller, U. S. Geol. Surv., Bull. 353, 1908.
343,
44. Diller, U. S. Geol. Surv., Bull. 260: 45,

(Taylorsville region.)
1905.
45. Fairbanks, Calif. State Min. Bur.,
(Indian Valley region.)
X: 23, 1890, and XIII: 665, 1896. (Mother Lode district.) 45a.
Hess, U.
S.
Geol.
430:
Bull.
Surv.,
1910.
23,
(Randsburg quad.)
47. Lind(N. Calif.)

Surv., Bull. 594, 1915.
(Auriferous gravels,
Surv., Prof. Pap. 73, 1911.
46. Hill, U. S. Geol.
gren, U. S. Geol.
Sierra Nevada.)
48. Lindgren, U. S. Geol. Surv., 17th Ann. Rept., II:
1, 1896.
(Nevada City and Grass Valley.) 49. Lindgren, Geol. Soc.
Amer., Bull. VI: 221, 1895.

(Gold Quartz veins.) 50. Lindgren,
U. S. Geol. Surv., 14th Ann. Rept., II: 243, 1894. (Ophir.) 51.
Ferguson, U. S. Geol. Surv., Bull. 580. (Alleghany mining district.) 52.
Ransome, U. S. Geol. Surv., Geol. Atlas, No. 63, 1900. (Mother Lode
district.)
53. Turner,
gravels.)
Colorado:
Amer.
1895.
(Auriferous
Geol. Surv., Bull.
54a. Crawford, Col. Geol. Surv., Bull. 4,
620, 1916.
(Gilpin Co.)
1913.
(Monarch dist.) 55.
332, 1883.
(Summit
XV:
Geol.
54. Bastin
and
371,
U.
Hill,
Emmons, Eng. and Min. Jour., XXXV:

56. Emmons, U. S. Geol. Surv., 17th
district.)
Ann. Rept., II: 405, 1896. (Custer Co.) 57.

U. S. Geol. Surv., Bull. 530, 1913. (Creede.)
ford,
Col.
59. Cross
Geol. Surv.,
1st Rept.:
and Spencer, U.
quadrangle.)
1909.
189,
Larsen,
George and Craw(Hahn's Peak field.)
Geol. Surv., Atl. Fol. 60.

(La Plata
S. Geol. Surv., Bull. 380:
(S.
21, 1909.
60. Hill, TJ.
Hills, Col. Sci. Soc., Proc. I:

S.
Geol.
Surv.,
and Bancroft, U.
61. Irving
Emmons and
58.
S.
E. Gunnison County.) 60a.

(Summit.) 6Cb. Hunter, U.
(Custer Co.)
S.
Bull.
580:
20,
1883.
25,
1914.
S. Geol. Surv., Bull. 478,
(Lake City.) 62. Irving, U. S. Geol. Surv., Atl. Fol. 153, 1907.
63. Lindgren and Ransome, U. S. Geol. Surv., Prof. Pap.
1906.
63a. Means, Econ. Geol. X: 1, 1915.
(Cripple Creek.)
1911.
(Ouray.)
54,
(Red
Cliff.)
(Montezuma
64. Patton,
district.)
Col.
Geol.
64a. Patton
Surv.,
and
1st
others,
Rept.:
Col.
105,
Geol.
1909.
Surv.,
Bull. 3, 1912.
(Park Co.) 65. Purington, U. S. Geol. Surv., 18th
Ann. Rept., Ill: 751, 1898. (Telluride.) 66. Ransome, U. S. Geol.
67. Ransome,
Surv., 22d Ann. Rept., II: 231, 1902.
(Rico Mts.)
U. S. Geol. Surv., Bull. 182, 1901. (Silverton.) 67a. Ransome, U.
S. Geol. Surv.,
Prof. Pap. 75,
and Garrey, U.
S.
1911.
(Breckenridge
dist.)
68.
Spurr
Geol. Surv., Prof. Pap. 63, 1908.

(Georgetown district.)
Georgia: 69. Eckel, U. S. Geol. Surv., Bull. 213: 57, 1903,
(Dahlonega district.) 70. Lindgren, U. S. Geol. Surv., Bull. 293.
(Dahlonega.)
71. McCallie,
Ga. Geol. Surv., Bull.
19, 1909.
Idaho:
GOLD AND SILVER
747
20th Ann. Kept., Ill: 75, 1900. (Silver

73. Lindgren, U. S. Geol. Surv., 18th Ann.
Co.)
(Idaho Basin and Boise Ridge.) 73a. Umpleby,
Kept., Ill: 625, 1898.
Kansas: 74. LindU. S. Geol. Surv., Bull. 528, 1913. (Lemhi Co.)
72. Lindgren,
City,
U.
S. Geol. Surv.,
De Lamar
Eng. and Min. Jour., LXXIV: 111, 1902. (Tests for gold and
Maryland: 75. Weed, U. S. Geol. Surv., Bull. 260:
(Great Falls.)
Michigan: 76. Wadsworth, Ann. Kept.,
128, 1905.
Minnesota: 77. Winchell and Grant,
1892, Mich. State Geologist.
Minn. Geol. and Nat. Hist. Surv., XXIII: 36, 1895. (Rainy Lake
Montana: 78. Emmons, U. S. Geol. Surv., Bull. 340:
district.)
78o. Emmons, W. H. Ibid.,
(Little Rocky Mountains.)
96, 1908.
Bull. 315: 45, 1907.
(Cable Mine.) 79! Lindgren, U. S. Geol. Surv.,
80. Weed,
Bull. 213: 66, 1903.
(Bitter Root and Clearwater Mts.)
U. S. Geol. Surv., Bull. 213: 88, 1903. (Marysville.) 81. Weed and
(Elkhorn
Barrell, U. S. Geol. Surv., 22d Ann. Rept., II: 399, 1902.
82. Weed and Pirsson, U. S. Geol. Surv., 18th Ann. Rept.,
district.)
Nevada: 82a. Barnes and Byler,
Ill:
(Judith Mts.)
589, 1898.
Min. and Sci. Pr., July 12, 1913. (Faulting and mineralization, Gold83. Becker, U. S. Geol. Surv., Mon. Ill, 1882.
(Comstock Lode.)
field.)
83a. Eakle, Univ. Calif., Dept. Geol., Bull. VII: No. 1, 1912.
(Tonopah minerals.) 836. Burgess, Econ. Geol., VI: 13, 1911. (Silver
halogens, etc., Tonopah.) 83c. Burgess, Econ. Geol., IV: 681, 1909.
(Tonopah.) 84. Emmons, U. S. Geol. Surv., Bull. 408, 1910.
(Elko,
Lander, and Eureka counties.) 85. Garrey and Emmons, U. S. Geol.
(Manhattan.) 85a. Hill, U. S. Geol. Surv., Bull.
Surv., Bull. 303.
540: 223, 1914.
(Yellow Pine dist.) 856. Hill, U. S. Geol. Surv.,
Bull. 594: 51, 1915.
(N. W. Nev.) 85c. Lindgren, U. S. Geol. Surv.,
Bull. 601, 1915.
(National dist.) S5d. Locke, Econ. Geol. VII: 583,
1912.
(Temperatures, Comstock Lode.) 86. Lord, U. S. Geol. Surv.,
Mon. IV, 1883. (Comstock mining.) 87. Ransome, Emmons, and
Garrey, U. S. Geol. Surv., Bull. 407, 1910. (Bullfrog.) 87a. Ransome,
U. S. Geol. Surv., Br.U. 414, 1909. (Humboldt Co.) 88. Ransome,
U. S. Geol. Surv., Prof. Pap. 66, 1909; also Econ. Geol., V: 301, 438,
89. Ransome, Econ. Geol., II: 667, 1907.
1910.
(Alu(Goldfield.)
lite in Goldfield district.)
89a. Schrader, U. S. Geol. Surv., Bull. 497:
Schra162,1912.
(Jarbridge, Contact, and Elk Mountain dist.) 896.
(Rochester dist.) 90.
der, U. S. Geol. Surv., Bull. 580: 325, 1914.
(Genetic
Spurr, Amer. Inst. Min. Engrs., Trans. XXXVI: 372, 1906.
90o. Spurr, Econ. Geol., X: 713,
relations western Nevada ores.)
1915.
(Tonopah.) 91. Spurr, U. S. Geol. Surv., Prof. Pap. 42, 1905.
(Tonopah.) 92. Spurr, U. S. Geol. Surv., Prof. Pap. 55, 1906. (Silver
Paak quadrangle.) 93. Young, Eng. and Min. Jour., XCIII: 167,
gren,
silver in shales.)
New England: 94. Smith,

(Me. and Vt.) 95. Graton,
North Carolina: 96. Laney, N. Ca. Geol.
S. Geol. Surv., 293.
(Gold Hill district.) 97. Nitze and Hanna,
Surv., Bull. 21, 1910.
New Mexico: 98. Anderson,
N. Ca. Geol. Surv., Bulls. 3 and 10.
Eng. and Min. Jour., LXIV: 276, 1897. (Mogollon Range.) 99.
Keyes, Amer. Inst. Min. Engrs., Trans., XXXIX: 139, 1909. (Lake
1912.
U.
U.
(Comstock Lode, conditions
225:
on.)
81, 1904.
ECONOMIC GEOLOGY
748
100. Lindgren and Graton, and Gordon, U. S. Geol. Surv.,

Valley.)
lOOa. Paige, U. S. Geol. Surv.,
Prof. Pap. 68, 1910.
(General.)
Oklahoma: 101. Bain, U. S.
Bull. 470: 109,1911.
(Pinos Altos dist.)
Geol. Surv., Bull. 225: 120, 1904.

(Wichita Mts.)
Oregon: 102.
(Bohemia
Diller, U. S. Geol. Surv., 20th Ann. Kept., Ill: 7, 1900.
102a. Grant and Cady, Min. Res. Ore., I, No. 6: 131, 1914.
district.)
(Baker
1902.
103. Kimball, Eng. and Min. Jour., LXXIII:

104. Lindgren, U. S. Geol. Surv., 22d
district.)
105. Pardee and Hewitt,
(Blue Mts.)
551, 1901.
dist.)
Kept., II:
Res. Ore.,
889,
Ann.
Min.
105a. Swartley, Min.
(Bohemia
Xo. 6, 1914. (Sumpter quad.)

South Carolina: 106. Graton,
Xo. 8, 1914. (X. E. Ore.)
U. S. Geol. Surv., Bull. 293, 1909. 107. Thies and Mezger, Amer.
Inst, Min. Engrs., Trans. XIX: 595, 1891.
See also
(Haile Mine.)
Xo. 113.
South Dakota: 108. Carpenter, Amer. Inst. Min. Engrs.,
Res. Ore.
I,
I,
Trans. XVII:
109. Irving, U. S. Geol. Surv., Bull. 225:

570, 1889.
S. Geol. Surv., Prof. Pap. 26, 1904.
(X. Black Hills.)
110. O'Harra, S. Dak. Geol. Surv., Bull. 3, 1902.
111.
(Black Hills.)
(Cambrian
Smith, Amer. Inst, Min. Engrs., Trans. XXVI: 485, 1897.
123, 1904,
and U.
Texas: Ilia. Dumble, Amer. Inst. Min. Engrs., Trans. XLIV:

1116. Phillips, Eng. and Min. Jour., Dec.
(Eocene placers.)
112. Udden, Tex. Univ. Min. Surv., Bull.
(Shaft er dist.)
United States: 113. Lindgren, Amer.
8: 54, 1904.
(Shafter dist.)
Inst. Min. Engrs., Trans. XXXIII: 790, 1903.
(X. Amei. production
and geology.) 114. Xitze and Wilkens, Amer. Inst. Min. Engrs.,
Trans. XXV:
Utah:
115. Emmons,
661, 1896.
(Appalachians.)
Amer. Inst. Min. Engrs., XXXI: 658, 1902. (Horn silver and Delamar
116. Hill, Col. Sci. Soc., Proc. V: 54, 1898.
mines.)
(Camp Floyd
117. Spurr, U. S. Geol. Surv.. 16th Ann. Rept,, II: 343,
district.)
1895.
Also references under Silver-Lead. 118. Warren,
(Mercur.)
VerEng. and Min. Jour., LXVII1: 455, 1899. (Daly-West Mine.)
mont: See New England.
Virginia; 118a. Watson, Mineral Resources
ores.)
588, 1913.
31, 1910.
of Virginia, 1907; Taber, Bull. 7, Va. Geol. Survey, 1913.

Washington:
119. Arnold, U. S. Geol. Surv.. Bull. 260: 154, 1905.
(Beach placers.)
119a. Lindgren
and Bancroft, U.
Wash and Republic
S. Geo!., Bull. 550, 1914.

(N. E.
120. Smith, Eng. and Min. Jour., LXXIII:
121. Smith, U. S. Geol. Surv., Bull.
district.)
dist.)
(Mt, Baker
379, 1902.
213: 76, 1903.
122. Spurr, U. S. Geol. Surv.,
(Central Washington.)
22d Ann. Rept,, II: 777, 1901. (Monte Cristo.) 122a. Weaver,
Wash. Geol. Surv., Bull. 6, 1911. (Blewett dist.)
Wyoming: 123.
Beeler,
Min. Wld., Dec.
Wyo. Univ.
Sch. of
26, 1908,
M.
125. Schultz,
County.)
(South Pass
1901.
Bull.,
district.)
(Sweetwater
124. Knight,
district,
U. S. Geol. Surv., Bull. 315.
Fremont
(Cent. Uinta
County.)
Canada:
126. Burrows, Ont. Bur. Mines, XIX, Pt. 3: 164, 1913.

(Gow128.
127. Burrows, Ibid., XXIV, Pt. 3, 1915.
(Porcupine.)
Burrows and Hopkins, Ibid., XXIII: 301, 1914. (Kirkland Lake and
ganda.)
Swastika.)
(Quartz
129.
mining,
(Wheaton
dist.,
Cairnes,
Can.
Klondike.)
Yukon.)
Geol. Surv., Rep.

130. Cairnes, Ibid.,
131. Cairnes, Ibid.,
Mem.
1911:
33,
Mem.
31,
37, 1913.
1912.
1912.
(Atlin
GOLD AND SILVER

dist.,
B.
C.)
132. Cairnes, Can. Min. Jour.,

133. Cairnes, Internal. Geol.
(Tellurium ores.)
Guide Book 10:
95.
Mem.
(Tulameen.)
26,
1913.
(Hedley, B. C.)
etc.)
137.
749
(Klondike.)
136. Cole,
Coleman,
Ont.
XXXII:
215,
135. Camsell,
Ibid.,
Mem.
Annual Repts. T. and N. O. Ry.

Bur.
1911.
Congr., Can., 1913,

134. Camsell, Can. Geol. Surv.,
Mines,
Bull.
1,
1897.
2,
1910.
(Cobalt,
(W.
Ont.)
138. Dresser, Can. Geol. Surv., Bull. 1028, 1908.

(L. Megantic.)
139. Keele, Can. Geol. Surv., Summ. Rept., 1911: 303, 1912.
(Meule
141. McConnell,
(N. S.)
Ibid., Mem. 20.
142. McConnell,
(Klondike high level gravels.)
143. McLean,
(Portland Canal.)
Ibid., Summ. Rept., 1910: 59, 1911.
Can. Dept. Mines, Mines Branch, Bull. 222, 1914. (Lode mining,
Yukon.) 144. Miller, for references on Cobalt, Ont., see under Nickel
and Cobalt. 145. Parsons, Ont. Bur. Mines, XXI, Pt. 1: 169, 1912.
Cr., Que.)
140.
Malcolm,
Ibid., Bull. 979, 1907.
(Lake of Woods, Manitou, Dryden.) 146. Rickard, Inst. Min. and

147. Wilson, Can.
(N. S.)
Met., London, Trans. XXI: 506, 1912.
Geol. Surv., Mem. 17, 1912.
(Larder Lake, Ont.) Many scattered
references in reports of Ontario Bureau of Mines, Canadian Geological
Survey, and Minister of Mines for British Columbia.
under Lead-Silver.
See also references
CHAPTER XX
MINOR METALS
MANGANESE
ALUMINUM
MERCURY
ALUMINUM
This
Ores.
is
one of the few metals whose ores do not present
a metallic appearance. Many different minerals contain aluminum,

but it can be profitably extracted from only a few. Common clay,
presents an inexhaustible supply, but the chemical
combination of the aluminum in it is such that its extraction up to
the present time has not been found commercially practicable,
although a number of processes with this end in view have been
for example,
patented.
The minerals which might serve as sources of aluminum,
together with the percentage of metal they contain are Corundum,
:
A1 2
per
cent);
AÔs,
H2 O
(53.3
diaspore,
cryolite,
(45.1
(39.13 per cent); gibbsite,
A1 2
3NaF-AlF 3
per
cent);
3 3H 2 O
(12.8
bauxite,
per
A1 2
cent);
3
2H 2 O
(34.6 per cent).
Of these, corundum is too valuable as an abrasive, and is not

found in sufficient quantity to permit its use as an ore of aluminum. Until the discovery of bauxite, cryolite, (see p. 332) was
the chief source of the metal, all of it being obtained from Greenland.
While aluminum ore
usually referred to as bauxite, it seems

the only one of the aluminum hydrates
no doubt that gibbsite may also occur. It
doubtful whether this

present,
is
is
is
and there is
in the Arkansas
known
be present
Bauxite derives
also to
in the
deposits,
and Watson
(16)
believes
it
Georgia ones.
name from Baux
in southern France, where

in
but
recent
discovered,
years large deposits have been
found in the United States. It is usually pisolitic in structure,
and may sometimes resemble clay in appearance. The comit
was
its
first
753
MINOR METALS
mon
impurities are silica, iron oxide,

variation in the amount of these
from
the following
occurrences.
analyses
of
751
and
both
and the
can be seen
titanic acid;
ingredients
domestic
ANALYSES OF BAUXITE
and foreign
ECONOMIC GEOLOGY
752
Knox dolomite (Fig. 268 and PI. LXXIV).

pronounced feature is their occurrence close to 900 feet above
sea level, few being found above 950 feet or below 850 (8)
The bauxite is believed by Hayes (8) to be a hot-spring deposit.
derived from the
FIG. 267.
map
Geologic
of
Alabama-Georgia bauxite region.
''M~
:
;
Ue
(After Hayes,
U. S. Geol. Surv., 16th Ann. Kept., III.)
It is underlain
by the Knox dolomite, and
this in turn by the Conwhich

are
several
thousand
feet in thickness, and
nasauga shales,
contain from 15 to 20 per cent of alumina and also pyrite. The
Alteration of the pyrite by
region is one of marked faulting.
percolating meteoric waters
FIG. 26S.
clay
Section of
soil
Talus
(g)
(c)
has
yielded
sulphuric acid,
(a) Residual mantle

(b) Red sandy
Bauxite with clay (e) Clay with bauxite
(/)
bauxite deposit,
Pisolitic ore
Mottled clay
(d)
(h)
which
Drainage ditch.
(After Hayes.)
MINOR METALS
753
attacked the alumina of the shale, with the formation of alum and
Both of these have been carried toward the
also ferrous sulphate.
by spring waters, but since they had to pass through the

higher-lying limestones, the lime carbonate acted on the dissolved
x
alum according to the following equation
surface
A1 2 (SO 4 ) 3
CaC03 =
A1 2
CaS0 +
4
C0
2.
The alumina thus formed was a light, gelatinous precipitate, which

was carried upward into spring basins on the surface, where it finally
The pisolitic structure is thought to have been caused by
settled.
the balling together of the gelatinous mass by currents.
The Georgia-Alabama deposits, which represent a unique type
of occurrence, were discovered in 1887, and have been worked
There have been some misgivings regardsteadily since that time.
ing the exhaustibility of the domestic supply, but the discovery and
development of extensive deposits
in
Arkansas have allayed these
fears.
This new bauxite-producing

Wilkinson County, Georgia (14)
lies within but near the margin of the Coastal Plain, about
30 miles east of Macon and the geological relations are entirely
.
area
from those of the principal belt in " Paleozoic Group "

of Georgia and Alabama.
The bauxite deposits, which occur
of
near
the
contact
the Tuscaloosa (Lower Cretaceous)
apparently
and Claiborne (Tertiary) formations, form beds up to 10 feet in
thickness, and the ore is generally either pisolitic or concretionary,
but some forms exhibit an amorphous character and even flinty
appearance. The color varies from white or cream to bright
different
Analyses are given above.

origin of the bauxite is a somewhat obscure problem, and
as the field is but little developed, evidence is difficult to secure.
red.
The
Veatch points out, however, that all stages of transition from

the clay to the bauxite can be observed, and suggests that the
latter has been formed by a desilication of the kaolinite in the
clay by circulating meteoric waters carrying some chemical that
was capable of abstracting the silica from the hydrous aluminum
silicate.
Tennessee Field.
Deposits of bauxite are
known on
the south-
east slope of Missionary Ridge, near Chattanooga (1), and were

worked for the first time in 1907. They are of the same character
as those found in the Georgia-Alabama

1
For
clearness, the water
and
may
be regarded
combined with alumina
is left
out.
field,
ECONOMIC GEOLOGY
754
as a northward extension of that region.

A large quantity of
ore has been taken out.
At Keenburg, Carter County, bauxite
is
found at an elevation of 2200
the
Watauga
shale (Cambrian).
feet in residual clays derived
Much
of the ore
is oolitic.
ANALYSES OF BAUXITE FROM MISSIONARY RIDGE, TENN.
from
MINOR METALS
755
but the deposits have net yet proven to be of commercial value

(6).
Deposits are also known near Silver City, New Mexico (2),
and appear to have been derived from a basic volcanic rock by
decomposition and alteration in place. Owing to their remoteness
from the
railroad, they are of little
commercial importance.
Paleozoic
Generalized cross sections illustrating the geologic history of the

A, lens of bauxite interstratified with the
Tertiary sediments; B, Tertiary hill with bauxite exposed on both sides, but
prevented from extending through the hill by a rise in the syenite surface;
C, Tertiary hill with bauxite on right, but absent on left; D, bauxite capping
on syenite; E, hill of Tertiary sediments with bauxite on both sides, separated
FIG. 269.
Arkansas bauxite occurrences.
valley between, in which is lens of detrital bauxite; F, Tertiary

with valley exposing underlying bauxite; G, Tertiary hill with concealed
bauxite under it.
(After Mead, Econ. Geol., X, 1915.)
by Tertiary
hill,
Foreign Deposits.
Bauxite has been found at a number of
That at Baux, from which it

associated with Cretaceous limestones and clays.
localities
named, occurs in beds

In Germany and IreOther deposits, associated
in southern France.
is
it occurs as a weathering product of basalt.

with limestones, are found in Austro-Hungary and Italy.
land
Uses
of Bauxite.
The most important use
of bauxite
is
for
the manufacture of aluminum, most of the Arkansas production

being employed for this purpose. A second important application
is
for the
manufacture of aluminum
salts,
most
of the
Georgia-Alabama product being sold for this purpose because

of its freedom from iron oxide, but chiefly because of its solubility
in sulphuric acid of a given strength.
The chief use of this metal
Uses of Aluminum.
is
for
making
wire for the transmission of electric currents, but a large quantity

of it is also used in the manufacture of articles for domestic or
culinary use, instruments, boats, and other articles where lighti
Dammer und
Tietze,
I: 262, 1913.
ECONOMIC GEOLOGY
756
ness
is
wanted.
It is also
employed
in the
manufacture
of special
among which may be mentioned magnalium, an alloy of

aluminum and magnesium; and wolframinium, a tungsten-aluminum alloy. One alloy of this type, known as partinium, is said
alloys,
to have a tensile strength of over 49,000 pounds per square inch;

McAdamite, an alloy of aluminum, zinc, and copper, is said to
possess a tensile strength exceeding 44,000 pounds per square
aluminum silver is an alloy of copper, nickel, zinc, and

aluminum; aluminum zinc includes a series of alloys containing
various proportions of these two metals. Another extending
application is that of powdered aluminum for the production of
intense heat by combustion, and in this connection it is used for
inch;
welding tramway
their oxides.
rails,
small
or for the reduction of rare metals from
amount
of
aluminum added
to steel pre-
vents air holes and cracks in casting, and it is also used to clear
molten iron and steel of all oxides before casting.
Alundum, an artificial abrasive, is made in large quantities at

Niagara Falls, by fusing calcined bauxite in the electric furnace.
Bauxite is also employed for the manufacture of bauxite bricks. 1
Still
another application of bauxite
is
for the
manufacture of
calcium aluminate to give a quick set to plasters. 2

The production of
Production of Bauxite and Aluminum.
bauxite in the United States has been as follows:
PRODUCTION OF BAUXITE IN THE UNITED STATES, 1890-1914, BY STATES,
IN
YEAR
LONG TONS
MINOR METALS
757
PRODUCTION, IMPORTS, AND CONSUMPTION OF BAUXITE IN UNITED STATES,

1910-1914, IN
YEAR.
LONG TONS
ECONOMIC GEOLOGY
758
IMPORTS OF
YEAR
"
ALUMINA
"
AND EXPORTS OF ALUMINUM FOR CANADA, 1912-1914
MINOR METALS
of
759
manganese varying from 15 to 40 per cent Mn); manganite
(Mn 2
H 2 0;
62.4 per cent Mn); rhodochrosite (MnC0 3

MnO). To these should be added franklinite
(FeZnMn) O (FeMn) 2 O 3
The manganese ores proper consist usually of a mixture of
oxides, and indeed these compounds are really the only ones of
61.7
3,
per cent
importance in the United States.
Pyrolusite and psilomelane

most important, and are often intimately associated, the pyrolusite generally assuming a crystalline and the
psilomelane a massive structure. They may locally have some
admixtures of iron oxide, and then they are of use in the steel
industry, but when free from iron they are, in addition, of value
for oxidizing and coloring purposes.
Wad is often of too low
grade, due to impurities, to be used as an ore of manganese, but
are
by
far the
sometimes employed for paint. Rhodochrosite, though found

common gangue mineral in some western mines (Rico, Colorado; Butte, Montana, silver mines), can hardly be regarded
as a source of manganese.
It has, however, been mined in some
1
quantity in the Huelva district of Spain, and in Merionethshire,
Wales (6).
it is
as a
Manganese oxides, in addition to being associated with iron,

as noted above, are sometimes mixed with zinc or silver.
It is
customary, therefore, to make a fourfold division into (1) manmanganiferous iron ore, (3) manganiferous silver
ore,
(4) manganiferous zinc residuum.
Manganiferous iron ores found in the United States consist
chiefly of limonite or hematite mixed with psilomelane, pyrolusite,
or wad, the mixture being an intimate one.
The high-grade ores
are of value for making spiegeleisen or ferro-manganese, but in
those running low in manganese this element is usually regarded
as an impurity.
Manganiferous silver ores are composed of a mixture of manganese
and iron oxides, containing small amounts of silver minerals, lead
In this class of ores, in which
carbonate, and sometimes even gold.
the iron usually predominates over manganese, the ores form the
ganese ores,
(2)
and
gossan of metallic sulphide bodies carrying iron, lead, zinc, and

silver sulphides in a quartz or calcite gangue.
Rhodonite and rhodochrosite sometimes occur in the unaltered' ores.
Tliis class of ores
uses as follows:
may
(1) ores
be divided into three classes (4) according to their

used mainly for their silver and lead values, the
iHayer, Zeitschr. prakt. Geol., 1911: 407.
ECONOMIC GEOLOGY
760
manganese and
iron content sometimes insuring a higher price because of

(2) ores too low in silver and lead to serve as sources
their fluxing action
and manganese to be employed

making ferro-manganese and spiegeleisen. If too low in manganese, it
may be used as an iron ore (3) ores too low in silver and lead to be used as
sources of these metals, and too low in iron and manganese to serve for
such ore is sold for flux, and the lead-silver content
alloys of these two
of these metals, but sufficiently high in iron
in
ultimately saved.
Manganiferous zinc residuum is obtained from zinc volatilizing

and oxidizing furnaces using New Jersey zinc ores, and consists
largely of the iron and manganese oxide which remains after the zinc
The minerals
has been volatilized and collected as zinc oxide.
in
the
and
willemite.
ore
are
franklinite, zincite,
present
Origin
Manganese oxide deposits are usually of secondhaving been formed by weathering processes, which
(7, 4).
ary origin,
caused the decay of the parent rock containing manganiferous
and the change of these latter to oxides. By circulating

water
ground
they have often been concentrated in residual clays.
iron
also may have been present in the parent rock, and
Although
the two are sometimes deposited together, still they have in
silicates,
instances been separated from each other, due to the fact

that conditions favorable for precipitation are not the same for
many
both, or because the soluble compounds of manganese formed by

weathering are sometimes more stable than corresponding iron
compounds, and hence
may
be carried farther by circulating
waters before they are deposited.

Manganese oxides may be precipitated from sea-water, as
nodules of this composition have been obtained by dredging from
the sea bottom.
They
are also
known
to occur as replacements of quartzite
(Piedmont region, Virginia).

The carbonate and silicate
veins (Butte,
rocks (Wales).
Montana)
may
occur as constituents of ore
or as bedded deposits in sedimentary
Distribution of Manganese-bearing Ores in the United States.

Although the manganese-bearing ores are widely distributed in the
United States, only a few localities are of commercial importance,
and the manganese-mining industry has been shrinking for several
years.
The reason
for this is that the
domestic ores are of
much
lower
grade than the imported ones, and often require washing and
sorting to render them marketable.
Moreover, they occur in small,
MINOR METALS
761
scattered pockets, often remote from lines of transportation, and
carry a high percentage of phosphorus and silica.

is therefore supplied largely by high-grade ores
from India, Brazil, and Russia, but the closing off of many of
may
The demand
war has stimulated manganese
these sources during the European

mining in the United States.
The occurrence
of the four classes
of
domestic ores
may
be
referred to separately.
The most important occurrences of this

Manganese Ores.
somewhat widely scattered type of ore are the Appalachian and
Piedmont regions, southern Mississippi Valley, and Pacific coast,
but the chief producing districts have been the James River Valley
and Blue Ridge regions in Virginia Cave Springs and Cartersville
districts in Georgia; Batesville district, Arkansas; and the Liver;
more-Tesla district in California.
Manganese deposits are found in the Atlantic

from
Vermont
states
to Alabama, and two states in this belt,
and
Georgia
Virginia (17, 6), lead in the domestic production.
In the crystalline rocks of the Piedmont province, deposits of
commercial value have been proven only in Virginia. In this
state the manganese area lies chiefly northeast and southwest of
Lynchburg. The ore minerals are mostly granular pyrolusite and
psilomelane, commonly occurring as nodules in residual clays from
mica schists, quartzite and limestones of Cambrian age. Umber
In several mines where the workings have
is sometimes present.
extended into hard rock, the ore occurs near the contact of quartzCrystalline limestone is found
ite, at times replacing the latter.
associated
with
the
ore
deposits, but its relations to the ore
closely
are not definitely known. 1
The Appalachian Valley deposits occur in two districts, viz.,
the Blue Ridge and New River.
The ores of the first district, which are the most important
Eastern Area.
of the two, occur in a series of irregularly distributed deposits

along the west foot of the Blue Ridge from Front Royal to
Roanoke, a distance of about 150 miles. This same belt in-
cludes the Blue Ridge iron-ore deposits, which

contain an appreciable amount of manganese.
may
may
So,
sometimes
too,
iron
be found in the manganese deposits.
The manganese
mentary
ore occurs in pockets in clays of residual or sedicharacter, along the contact of the Lower Cambrian
1
Supplied by T. L. Watson.
ECONOMIC GEOLOGY
762
with the overlying
quartzite
formation,
and more rarely
in
fissures penetrating the quartzite.
Four types
They
are:
(1)
of ore are found, all of
which
may
occur in the same deposit.
black psilomelane kidneys in clay; (2) irregular, often porous
masses of psilomelane with layers cf crystalline pyrolusite, also in clay;

(3) breccia ore in large massts consistirg of sandstone or chert fragments,
with pyrolusite or psilomelane filling; (4) replacements or cavity fillings,
mainly pyrolusite, in sandstone or sandy clay. The mine at Crimora
The ore forms pockets
(Fig. 270 and Plate LXXII) is one of the best known.
5 to 6 feet thick, and 20 to 30 feet long in a deposit of clay 276 feet thick.
SECTION NO.
2.
SECTIOT>IO.
FIG. 270.
Sections of
Manganese
4.
deposit. Crimora, Va.
(After Hall.)
In the New River district, the ore, which is mainly psilomelane,

occurs as large masses mixed with iron ores in residua) clay, but
is
of little
commercial importance.
The
Virginia areas mentioned extend southward into Tennessee, and some ore is mined there, (6, 9a)
TIG. 271.
Map
showing Georgia manganese areas. (After Watson, Amer.

Min. Engrs., Trans. XXXIV.)
Inst.
.a
2
'3
'3
"~-
.h -2
ECONOMIC GEOLOGY
764
Georgia.
In northern Georgia
(7, 16)
the ore results from the
shales, Cave Spring and Cartersville

decay
The deposits are found in
localities
(Fig. 271).
being important
both
the
underlain
the areas
crystalline and Palseozoic rocks,
by
of limestones
and
but only those associated with the latter have proven to be of

importance. In this region the rocks consist of Cambro-Silurian
limestones and quartzites, which have been much folded and
faulted,
and have been weathered down to a residual
clay,
which
The
ore occurs as pockets,

lenticular masses, stiingers, grains, or lumps, irregularly scattered
through the clay, and rarely forming distinct beds. None of the
is
often not less than 100 feet thick.
deposits are large, though
some 30
feet in length
have been worked.
Section in Georgia manganese area, showing geologic relations of

manganese, limonite, and ocher. (After Watson, Amer. Inst. Min. Engrs.
FIG. 272.
Trans.
More
XXXIV).
or less limonite, barite, ocher,
and bauxite may be associated
with the ore (Fig. 272), and, indeed, complete gradations from manganese to iron are found, as shown by the following analyses:
Mn
Fe
PLATE LXXIV
FIG.
FIG.
2.
1.
View
Furnace
of bauxite bank,
for roasting
Rock Run,
Ala.
mercury ore, Terlingua, Tex.
(H. Ries, photo.)
(H.
W.
Turner, photo.)
(765)
ECONOMIC GEOLOGY
766
The Georgia
deposits have been worked for a number of

manganese was formerly marketed chiefly in
(15)
and the
years,
England; but the output is now sold entirely in the United States.
The ore, which has to be purified by washing and crushing, is used
in part for paint and in part for steel manufacture.
Other Eastern Occurrences.
localities in
Vermont
(6),
Deposits are
North Carolina,
(G)
known
at
several
South Carolina
and Pennsylvania (6).

Lower Mississippi Valley and Gulf Region.
(6),
The Arkansas
deposits are the only important ones in this region.

Arka?isas.
Manganese ore is found in the region around
(10, 13), associated with horizontally stratified limestones and shales, ranging from Ordovician to Carboniferous Age
The Cason shale, of Silurian Age, occurring near the
(Fig. 273).
Batesville
FIG. 273.-
Ordovician
Section in Batesville, Ark., manganese region, illustrating geological
structure
able ore.
and
relation of different formations to marketable
(After
Van
Ingcn, Sch. of
M.
Quart.,
and non-market-
XXII.).
middle of the section (Fig. 273&), carries manganese nodules high

in phosphorus, which are not marketable, and others are found
in the pits of residual clay derived from it.
Farther down the
slopes marketable ore (Fig. 273c), which has been derived by
leaching of the first-mentioned ore, is found occurring in residual
pockets in the lower-lying limestones, while the residual clays
(Fig. 273a), formed at a higher level than the Cason shale, are
barren of manganese.
Other Occurrences.
Small deposits are said to occur in Hick-
man County,
Tennessee, and Llano County, Texas.

T\vo types of ore are found in California.
Western States.
The
in
first of
the
Meadow
Sierra
these consist of veins of pyrolusite, and psilomelane

(Carboniferous) formation, occurring near
Calaveras
Valley,
Nevada.
Plumas County, and at other points in the

occurs near the coast north and south
The second
MINOR METALS
767
San Francisco, as
local thin lenses, interbedded with jaspers

At the Ladd mine
(Jura-Trias) formation.
near Livermore, the ore lies in a fault fissure, 4 to 5 feet in width,
of
of the Franciscan
and forms cavity fillings, infiltrations, and replacement deposits

in red and yellow clays, and as veins and breccia cement in the
The wall rock is jasper (6).
wall.
Small deposits are also known in Utah where, in Grand County,
the ore occurs as replacements in Triassic limestone (6), and near
Golconda, Nevada. The latter, which is bedded, and is interstratified with calcareous and siliceous tufa, appears to be a hotspring deposit in a small tufa basin.
Those of the Appalachian Valley
Manganiferous Iron Ores.
have already been referred to in connection with the manganese
The most important deposits are in Vermont, Virginia

ores.
and Tennessee, and consist chiefly of psilomelane and limonite
mixtures.
Much iron ore of the Lake Superior district carries
from 1 to 10 per cent metallic manganese, and some large bodies
are known on the Cuyuna range.
Other occurrences have been
noted from Gunnison County, Colorado (10), Juab County, Utah,
and Missouri, but they are not of commercial value.
The most important deposits
Manganiferous Silver Ores.
are those found at Leadville, Colorado. Manganiferous silver
and iron ores are important in the oxidized zone of the Leadville
forming large masses adjacent to the sulphide deposits.

have suggested that they represented infiltrations from
the porphyry, but P. Argall (l) has shown that manganiferous
siderite in irregular masses is abundant as a limestone replacement. He therefore suggests that weathering of the siderite has
district,
Some
(4)
yielded the manganese. The ores range as follows: Manganese,

trace-40 per cent;
iron, 8-50 per cent; lead, trace-5 per
cent; insoluble, 5-34 per cent; silver (in 1914) 2-25 ounces
Ores of similar character are found at

gold, trace.
Neihart and Castle, Montana. Manganese is also found in the
silver veins at Butte, Montana, but is of little commercial value.
Still other manganiferous silver ores have been noted from
per ton;
New Mexico, Arizona, Utah, and Nevada,

but appear to be of little commercial importance. Some found in
the Tintie district, Utah, are used as flux at the local smelters.
scattered localities in
Canada
number of
(8).
The Canadian production is very small. A

known in Nova Scotia, New
scattered deposits are
Brunswick, and Quebec.
ECONOMIC GEOLOGY
768
Russia 1 is by far the largest producer,

of the ore coming from the Sharopan district of the Caucasus,
it occurs as a stratified deposit of oolitic oxides between Eocene sandstone and Cretaceous limestone. The beds do not exceed a foot in thickness,
but the ore is high grade.
most
where
Much manganese
India.
ore
is
The
Presidencies of Central India. 2
mined
in
the Madras and
Bombay
and occur: (1) Associated with or derived from manganese-bearing silicates, as bands or lenticles,
in Archaean gneisses and schists; (2) as superficial formations on the outcrops of such rocks as quartzites, shales, slates, and hematite-schists; and
ores are all oxides
concretions in laterite.
(3) as
the third largest world's producer, has important deposits in the

province of Minas Geraes. The manganese is associated with iron ores;
and may be of bedded character or detrital nature.
Brazil,
Uses of Manganese.
Manganese is used in the manufacture of
whose
value
depends not only on the amount of manganese,
alloys,
but also on the absence of sulphur and phosphorus. Spiegeleisen
contains under 20 per cent manganese, and ferromanganese, a similar
The amount of silicon and
alloy, has from 20 to 90 per cent of it.
carbon present in these varies.
Other alloys are manganese bronze, manganese and copper, with
or without iron.
Some alloys of manganese, aluminum, and copper,
known
as Heusler's alloys, are important because of their magnetic

Other elements alloying with manganese are zinc, tin,
properties.
lead,
magnesium, and
oxide
Manganese
and silver reduction
is
silicon.
used
(1) as
a substitute for iron oxide in copper
(2) as an oxidizing agent in the manufacture

of chlorine, bromine, and disinfectants
(3) as a decolorizer of green
in
calico
as
a
printing and dyeing, in the
glass
(4)
coloring agent
;
of glass, pottery, bricks, and also paints

(5) in the manufacture of the Leclanche battery and of dry cells, for which purpose a
considerable amount is consumed annually.
making
Some manganese compounds have a medicinal value, and rhodonsometimes cut for a gem stone.
Production of Manganese.
Although much used in steel manu-
ite is
facture, the domestic production is small because of the inferior

character of the native ores, therefore the largest consumers rely
upon
foreign sources of supply.
iCauldwell, Min. and
Sci.
Engrs., Bull. 113, 1916.

2
Ferrnor, Geol. Surv., India,
3 Harder loc. cit.
p. 785.
Pr.,
CV:
113,
Mem. XXXVII,
1912.
1909.
Harder, Amer. Inst. Min.
MINOR METALS
769
The following table gives the total quantity of the several kinds
of ore produced in the United States.
The annual production
since 1885 has fluctuated more or less, and there has been a strong
decline in the production of the straight
manganese
ores.
PRODUCTION OF MANGANESE ORES IN THE UNITED STATES, 1912 TO

IN
YEAR
LONG TONS
1914,
ECONOMIC GEOLOGY
770
Ores containing less than 40 per cent manganese or more than 12 per
cent silica or .225 per cent phosphorus are subject to acceptance or refusal
at the buyer's option.
PERCENTAGE OF METALLIC
PRICE PER UNIT OF
MANGANESE
MANGANESE IN ORE
Over 49
48 to 49
IN
43 to 46
2o
25
24
40 to 43
23
CENTS
Settlements are based on analysis of sample dried at 212 F., the percentage of moisture in the sample as taken being deducted from the weight.
The manganese ores for oxidizing and coloring purposes are valued according to the quantity of manganese peroxide present, their consistency,
etc.
An ore for use as an oxidizer must contain at least 80 per cent manganese dioxide, and not more than 1 per cent iron. There is no established
schedule, and such ores have usually been obtained largely from the Caucasus
region of Russia.
Owing to the war, prices went as high as $70 a ton. Few
deposits in the United States can supply this demand.
Manganiferous iron ores containing 15 to 35 per cent manganese range

from S3. 50 to $6 per ton.
in 1913 amounted to 345,090 long tons valued
and in 1914 to 283,294 long tons valued at
These came chiefly from Brazil, British India,
The imports
at $2,029,680,
$2,024,120.
Russia, and the United Kingdom.
The production of Canada in 1914 amounted to 28 short tons

valued at $1120. The exports for the same year were 30 short
tons, valued at $750.
World's Production.
The
following table
available statistics with regard to

of
manganese
the latest
ore.
WORLD'S PRODUCTION OF MANGANESE ORE,

COUNTRY
gives
American and foreign production
IN
LONG TONS
MINOR METALS
771
REFERENCES ON MANGANESE
1.
Argall, P.,
Min. and
Sci.
Pr.,
Dolbear, Min. and Sci. Pr.,
CIX:
CX:
50, 128, 1914.
172, 1915.
(Leadville, Colo.)
Also
(Calif, industry.)
2.
ibid.,
258.
(Ladd mine, Calif .) 3. Eddingfield, Econ. Geol., VIII: 498, 1913.
(Manganese in superficial alteration.) 4. Emmons and Irving, U. S. Geol.
5. Hafer, Eng. and Min.
Surv., Bull. 320: 34, 1907.
(Leadville, Colo.)
XCVIII
Jour.,
N.
6. Harder, U. S. Geol. Surv., Bull.

(S. Ca.)
Hayes, Amer. Inst. Min. Engrs., Trans. XXX: 403,
Kramm, Can. Min. Inst., XV: 210, 1913. (New Ross,
1135, 1914.
427, 1910. (U. S.)

1901.
8.
(Ga.)
7.
(Utah.)
Leith, U. S. Geol. Surv., Bull. 285: 17, 1906.
Min. Res. Tenn., I, No. 6, 1911. (Tenn.) 95. Penrose,
Jour. Geol. I: 275, 1893.
(Chemical relations of iron and manganese
9.
S.)
9a. Nelson,
in
10. Penrose,
sedimentary rocks.)
Ark. Geol. Surv., Kept, for 1890,
11. Tarugi, Eng.

(Uses, ores, and deposits.)
Jour., July 12, 1913.
(Use of siliceous manganese minerals.)
Vol.
I,
1891.
Hise and Leith, U. S. Geol. Surv., Mon. LII, 1911.

13.
Van
Ingen, Sch.
of
M.
Quart.,
XXII:
12.
Van
Superior region.)
(L.
318,
and Min.
1901.
(Batesville,
Min. and Sci. Pr., CHI: 201, 1911. (Low.

15. Watson, Amer. Inst. Min. Engrs., Trans. XXXIV: 207,
Calif.)
1904.
16. Watson, Ga. Geol. Surv., Bull. 14:
(Ga.)
158, 1908.
17. Watson, Min. Res. Va., 1907:
235.
18. Young,
(Ga.)
(Va.)
Can. Geol. Surv., Mem. 18, 1911. (Bathurst dist., N. B.)
14. Wallace,
Ark.)
MERCURY
Ore Minerals.
While mercury
is
sometimes found native in
the form of quicksilver, the most common ore is cinnabar (HgS),

which contains 86.2 per cent mercury. Native amalgam of mer-
cury and silver
is
known, and
calomel, the chloride, as well as
other compounds, are sometimes found.

Among the less common ones may be mentioned: montroydite
(HgO); tiemannite (HgSe); onofrite (Hg(S,Se)); and coloradoite
(HgTe)4.
Schwatzite, the mercurial tetrahedrite, is not uncomof localities in Europe and
mon, being known from a number
South America. In the United States it is known in the Blue

Mountains, Oregon, and may have been the original ore mineral,
whose decomposition formed the present mercurial ore minerals
at some other localities (Plomosa district. Arizona and La Plata
district,
Colorado).
The commercial sources of mercury contain a comparatively

small amount of other metallic minerals, although a number of
may
at times occur
in small quantities in veins of the other metals.
Thus it is a
found in some
different ones
have been found and cinnabar
frequent accompaniment of stibnite, and
is
also
ECONOMIC GEOLOGY
772
The dyscrasite found in the Cobalt,

Ontario, silver veins, also carries mercury.
Mode of Occurrence.
Mercury ores are not confined to any
gold and copper deposits.
particular formation, but are found in rocks ranging from the

Ordovician to Recent age in different parts of the world. Nor
are they peculiar to any special type of rock, although igneous

rocks are often found in the vicinity of them. They occur as
veins, disseminations, or as masses of irregular form.
Silica,
either crystalline or opaline, and calcite are common gangue
while pyrite or marcasite are rarely wanting, and
minerals,
bitumen
is
widespread.
Many mercury deposits occur

may be marked by hot springs.
along lines of fissuring, and these
The commercially valuable occurrences have apparently been

deposited at shallow depths, although mercury minerals are sometimes found im small quantities of the intermediate and even
deeper vein zone.
The
Origin.
by Becker
that
(3)
silica
origin of
and
(either
later
mercury ores has been studied
by Schrauf
crystalline
or
(17).
The former
amorphous) and
chiefly
points out
calcite are
common gangue
minerals, but pyrite or marcasite are almost

equally abundant, as is also bitumen. In addition to these, the
ores show an irregular association with other metallic minerals,
such as antimony, silver, lead, copper, arsenic, zinc, or even gold.
Becker believes that the cinnabar has been precipitated from

ascending waters by bituminous matter, having come up in
He further
solution as a double sulphide with alkaline sulphides.
and
are not
that
the
suggests
deposits represent impregnations
replacements.
Hot springs carrying mercury in solution are known at Steamboat Springs, Nevada (PI. XXXIX, Fig. 2), and Sulphur Bank,
California.

California has always
been the most important, and in fact, at times, the only producing state. Deposits are, however, also known in Texas,
Oregon, Utah, Nevada, New Mexico, and Arizona.
-
California
(3, 4)
(Fig. 274).
The
California ores occur chiefly
metamorphosed Cretaceous or Jurassic rocks, with some in the

Miocene and even Quaternary. The deposits, which are termed
"
"
chambered veins
by Becker, are fissured zones. Eruptive
rocks seem in many cases to be involved in the ore formation,
in
MINOR METALS
and at
New Almaden
body.
The
773
a rhyolite dike runs parallel with the ore

ore here occurs along the contact between serpentine
and shale, filling in part the

which are the largest in the
a breccia. These mines,

have been worked to a depth of
interstices of
state,
over 2,500 feet.

At the New Idria mine,
located in southeastern
San Benito County, and

which has been worked
almost continually since
1853, the ore bodies occur
as stockworks in meta-
morphic rocks of Lower

Cretaceous age, just south
of their contact with the
unaltered
sediments
the Chico (Lower Cretaceous) formation. The

ore,
which consists
of a
mixture of pyrite and cinnabar, with a gangue of

silicified
and
brecciated
FIG. 274.
Map
of California
mercury
localities.
metamorphic sandstones
and shales, may occur as
veins, stockworks or impregnations.

note that in driving a tunnel to connect
1060-foot level considerable natural gas was en-
It is interesting to
with the
countered, and that at another locality, New Almaden, exhaladioxide were encountered in some of the lower
tions of carbon
levels.
Other occurrences are in Colusa County, where the cinnabar is found in

and in Napa County, where it occurs along the contact
of sandstone and slate.
The minerals associated with these are bitumen,
free sulphur, stibnite, mispickel, gold and silver, chalcopyrite, pyrite,
The vein is a fissure filled
millerite, quartz, calcite, barite, and borax.
with brecciated fragments, and cuts through sandstone, shale, and augite
andesite, the cinnabar cementing the breccia together, but at times also
impregnating the walls. Hot waters which circulate through the vein
altered serpentine,
still
deposit gelatinous
silica.
At Steamboat Springs the waters carry gold, sulphide of arsenic, antimony, and mercury, sulphides or sulphates of silver, lead, copper, zinc,
iron oxide, and possibly other metals.
They also contain sodium carbonate, sodium chloride, sulphur, and borax.
Cinnabar is known in Lane and Douglas counties, Oregon.
ECONOMIC GEOLOGY
774
Texas
Texas
(6, 14, 19)
(Fig. 275),
The Terlingua district of Brewster County,

has aroused much interest in recent years.
.
The area of importance is about two miles wide north and

south and fifteen miles east and west, and lies in southern
Brewster County, about 300 miles southeast of El Paso, and
110 miles south of Marfa.
Map
FIG. 275.
It
is
7 miles to the
showing Texas mercury region.

Jour.,
Rio Grande and
(After Hill,
Eng. and
Min
LXXIV.)
Mexican border. The remoteness from the railroad and lack of

water have formed serious obstacles in the development of the
district.
The rocks are sediments of Upper and Lower Cretaceous

cut by Tertiary volcanics, and the following section is
age
involved
Tertiary tuffs
and
lavas, forming sheets, dikes, laccoliths,
The rock types included

Upper Cretaceous.
flows.
200
100
400
Ponderosa marls
Austin chalk
Eagle Ford shales
Lower Cretaceous.
and surface
are andesites, rhyolites, phonolites, and basalts.

ft.
ft.
ft.
_,
Vola limestone
Arietina clays or Del Rio shales
Washita or Fort Worth limestone
Fredericksburg or Edwards limestone
There has been important
75
75
100
1000
ft.
ft.
ft.
ft.
faulting, the strike of the chief dislo-
cation being northwest-southeast, but that of the ore-filled fissures

is northeast-southwest.
MINOR METALS
775
The ore bodies have thus far been found chiefly in the Washita
and Fredericksburg limestones, but more recently in the Eagle Ford
The ore is most frequently found in fissure veins (Fig. 277)
shales.
but some occurs in
breccias and as lateral,
enrichment deposits.
The chief ore mineral
cinnabar, which is
often closely associated
is
with pyrite or its oxidation products, especially

in the breccia lodes.
Calcite
the most im-
is
portant gangue mineral.
Gypsum
ondary)
(probably secis
common and
hydrocarbons
may
It is of interpresent.
est to note that three
new
VERTICAL SECTION CALIFORNIA HILL.TERLINSOA
be
FIG.
Vertical
276.
Tcrlingua, Tex.
section
of
California
Hill,
(After Turner, Econ. Geol., I.)
minerals, terlinguaite, eglestonite, and montroydite, all oxychlorides of mercury, were discov-
ered in these ores.
The
ore treated in the furnaces
varies from .75 to 2.5 per cent

mercury, while that sent to the
4 per cent or over.

open
there being few shafts, so no
retorts runs
Most
277.
Section of cinnabar
vein in limestone, Terlingua, Tex.
(After Phillips, Univ. Tex. Min.
FIG.
Sure., Bull. 4).
pits,
of the workings are
definite idea of the
underground
reserves exists.
1
Foreign Deposits.
Spain is the largest producer, followed by Italy and
In the first-named country, the Almaden deposit is the world's
greatest producer. Here the ore forms impregnations and replacements of
three steeply dipping beds of Silurian quartzite. The principal bed is 8
to 14 meters thick, and the ore averages about 8 per cent mercury. This
deposit, unlike most others, extends to a considerable depth.
At Monte Amiata in Tuscany the ore occurs as disseminations, chimneys,
Austria.
Cretaceous and Tertiary limestones, shales and sandstones associated

with trachyte.
A third large deposit is that at Idria, Austria, where the ore, chiefly cinnabar, but sometimes native mercury, is found forming impregnations,
etc., in
Vogt, Krusch and Beyschlag, Translation
by
Truscott, I: 464, 1914.
ECONOMIC GEOLOGY
776
stockworks and veins in limestones, shales, marls, and dolomites of Triassic

There seems to be a connection between the ore deposition and a
age.
large overthrust of post-Cretaceous times.
Mexico and Peru contribute some mercury
Thin section
FIG. 278.
of limestone
to the world's production.
impregnated and replaced

X33.
(?)
by cinnabar,
Idria, Austria.
Uses of Mercury. Quicksilver is used chiefly in the manufacture of electric appliances, drugs, scientific apparatus, and
fulminate for explosive caps. About one-third of the domestic
employed for the last-named purpose in
used in decreasing quantity for the recovery
of precious metals, especially gold, because of the increased use
output
is
said to be
normal times.
It is
of the cyanide process, the decrease of free-milling gold ores
placer gravels,
and the increased
efficiency
and economy
in
and
stamp
Mercuric
milling, resulting in a decreased loss of quicksilver.
oxide (red oxide of mercury) is the active poison in antifouling
paint for ships' bottoms. Quicksilver, though formerly much
used for silvering mirrors, is now largely replaced by silver
nitrate
Cinnabar is easily decomposed by heat, giving off when

or retorted with quicklime, the mercury vapors and sulphur
dioxide in one case, or mercury, calcium sulphide, and calcium sulphate in
Extraction.
heated in
air,
ihe other.
The mercury
is
collected
by subsequent condensation.
MINOR METALS
777
Retorts are adapted only to ores carrying 4 per cent or more of mercury,
while low-grade ores are treated in shaft furnaces, some of the more modern
ones being capable of treating an ore running as low as .25 per cent metal.
California was for many years pracProduction of Mercury.

only domestic source of mercury, but in 1898 Texas
tically the
became a producer, and will no doubt continue

of mercury is quoted in flasks of 75 pounds net.
so.
PRODUCTION OF QUICKSILVER IN THE UNITED STATES, 1912,

BY STATES, IN FLASKS or 75 POUNDS
STATE
The output
1913,
AND
1914,
ECONOMIC GEOLOGY
778
at $271,984.
The exports
for 1913 were 1140 flasks, valued at
$43,574, while those for 1914 included 1446 flasks, valued at

The exports went to nearly all parts of the world.
$70,753.
The imports are greater than formerly while the exports are
less.
WORLD'S PRODUCTION OF QUICKSILVER, 1911-1914, IN FLASKS OF

75 POUNDS EACH
COUNTRY
CHAPTER XXI
MINOR METALS
(Continued)
ANTIMONY TO VANADIUM
ANTIMONY
Ore Minerals.
Stibnite (Sbâ) is the
antimony, and the metal
is
most important ore of

any other mineral,
rarely obtained from
although native antimony has been sparingly found. The oxide

senarmontite (Sb2C>3) seldom occurs in any quantity. A small
amount
of
antimony
stibnite, together
is
present in some silver-lead ores.
with a gangue of quartz, and frequently
The
calcite,
usually forms veins cutting igneous, sedimentary, or metamorphic
Other
rocks, and less often is found in replacement deposits.
metallic sulphides may be associated with the antimony; some
deposits are auriferous, and less often argentiferous.
Stibnite is not necessarily a mineral of the shallow-vein zone,
for it may occur in deposits formed at intermediate depths, or
even in the deep-vein zone, but commercial deposits occur chiefly

in the shallow zone.
Cairnes
(2) classifies
antimony deposits as
follows:
Ores deposited in cavities, chiefly fissure veins.

a. Of value, chiefly or entirely for antimony
I.
6.
Auriferous stibnite.
c.
Antimony and
silver.
Replacement, chiefly in limestone.
II.
Distribution of Antimony in United States.

Antimony has
been found at a number of localities in the Cordilleran region,
but the great distance of the deposits from the railroad has helped
to make them of little commercial value, and the domestic production is very small and irregular.
It is therefore only the richest and best-located deposits that
Some of the known ore bodies are also said to lack
are worked.
value because of their content of arsenic, zinc, or lead minerals,

779
ECONOMIC GEOLOGY
780
and hence are refused by the buyers so long as they can get purer
ores (Hess).
gold and silver ores carry some antimony, and in smeltcombines with the lead, giving a product known as antimonial lead, much of which is produced in the United States.
The large amount of antimony now manufactured in the
United States is obtained: (1) as a by-product from the smelting
of foreign and domestic lead-silver ores containing small quantities of antimony;
(2) from antimony regulus, or metal from
foreign countries; (3) from foreign ore; and (4) from some copper
Many
ing
it
ores.
Hess states that in 1914 a few tons were separated from the
anode muds of blister copper 'made from Butte ores.
Very little has been published regarding the occurrence of antimony ores in the United States. Hess has described some deposits
in Arkansas (4), where the antimony occurs as bedded veins in
sandstones and shales, with a quartz gangue, and associated with
a number of different metallic minerals. The deposits are of
doubtful value, except possibly when high market prices prevail.
Along Coyote Creek, in Garfield County, Utah (7), there are

found flat-lying deposits of stibnite and its oxidation products
in Eocene (Tertiary) sandstone and conglomerates.
The ore in
sight is all low grade, although some rich pockets have been
worked out
in the past.
and basalts are known in western

Nevada, and have been specially referred to in the National
district (6).
There, the fissures, which have a quartz gangue,
all carry more or less stibnite, together with small amounts of
Stibnite veins in rhyolites
pyrite, blende, etc.
Canada.
The Canadian production
of
antimony
is
small and
spasmodic.
It occurs at West Gore, Nova Scotia (4) in fissure veins in
Cambrian slates. The minerals are stibnite, native antimony,
pyrite (auriferous), mispickel, kermesite (Sb2S2O) in a gangue of
crushed slate, quartz and calcite. Other veins are found at Prince
William, near Fredericton, New Brunswick, (8). An interesting

series of veins in granite is found in the Wheaton River district,
Yukon
Territory.
The
veins,
vary from a few inches to 5
which occur
tetrahedrite, argentiferous galena

of quartz (2)
.
chiefly in granite
and
feet in width, carry stibnite, sphalerite,
and antimony ochre,
in a
gangue
MINOR METALS
781

China is the largest producer of the world,
the deposits of the Hunan Province l being of importance. There the ore
near Hsinhua is distributed in seams, pockets and bunches in Carboniferous
dolomite, while at the Pan-shi mines it occurs as fissure veins in sediments.
France has also been a large producer, numerous deposits being found in
the Central Plateau region.
The veins, which cut schists, granite, and also
elastics, carry stibnite in a quartz gangue.
The Japanese veins are found chiefly in Mesozoic and Paleozoic sediments,
often near quartz prophyry, or even in it.
2
3
4
Replacement deposits are known in Italy, Algeria, and Mexico.
Uses.
Antimony metal
is
used chiefly in the manufacture of
Type metal, which is an alloy of lead,

and
has
the
bismuth,
property of expanding at the moantimony,
ment of solidification. Britannia metal is tin with 10 to 16 per cent
antimony and 3 per cent copper. Babbitt, or antifriction metal
consists of antimony and tin, with small amounts of lead, copper,
bismuth, zinc, and nickel. Tartar emetic, a potassium-antimony
tartrate, antimony fluoride and ammonium sulphide, and other
double salts are used in medicine and as a mordant for dyeing, while
antimony persulphide is employed for vulcanizing and coloring
alloys of lead, tin, zinc, etc.
rubber.
Antimony
trioxide
is
employed as a substitute
for white
used in a glaze for coating enameled iron ware, as a reducing agent in chemical work, and
The trichloride is used in
as a detector of alkaloids and phenols.
lead, zinc oxide, etc., in pigments.
It is also
bronzing gun barrels, in coloring zinc black, and as a mordant for

patent leather and silver. Antimony trisulphide is used in pyroPRODTJCTION OF ANTIMONY IN THE UNITED STATES, 1912-1914, IN
SHORT TONS
ECONOMIC GEOLOGY
782
"
technics
for
making
''
if
Bengal
fire."
Antimony chromate,
or
used for coloring.
Naples yellow."
The production of metallic antiProduction of Antimony.
and
from
domestic
foreign ores since 1912 was as shown
mony
in the table on page 781.
ANTIMONT, AXTIMONT ORE, AND SALTS OF ANTIMONT IMPORTED AND
ENTERED FOR CONSUMPTION IN THE UNITED STATES, 1912-1914. rx
POUNDS
YEAR
MIXOR METALS
783
In 1914 the value of the antimony content of antimonial lead

10.5 cents per pound.
was
REFERENCES ON ANTIMONY
1.
2. Cairnes, Can. Min.

Cairnes, Can. Geol. Surv., Mem. 37, 1913.
Inst.,
XIII: 297, 1911. (Wheaton River, Yukon Ter.) 3. Comstock, Ark.
4. Haley, Eng. and
Geol. Surv., Ann. Rept. for 1888, I: 136.
(Ark.)
Min. Jour., LXXXVIII: 723,1909. (West Gore, N. S.) U. S. Geol.
Bull.
601,
5. Hess, (Ark.); also articles on Anti241, 1908.

Geol. Surv., Min. Res. 6. Lindgren, U. S. Geol. Surv.,
7. Richardson, Ibid., Bull.
1915.
(National dist, Nev.)
340:
253,
1907.
Surv., Bull. 340;
mony, U.
S.
(Utah.)
Economic Minerals
of
8.
Young, Can. Geol. Surv., Geology and
Canada (N.
B.)
ARSENIC
Ore Minerals.
distributed in
Although arsenic-bearing minerals are widely
many
countries, the commercially valuable occur-
rences are few, and moreover few arsenic-bearing minerals are

important as sources of the metal. Arsenopyrite (FeAsS with
46.02 As) is the most important and the most widely distributed
It may occur in schists, gneisses, pegof the arsenic minerals.
contact-metamorphic deposits or quartz veins, and

favors
usually
deep-zone conditions. Other sulphides may be
with/
associated
it, as well as gold and silver.
Orpiment (As2Ss, 60.96 As) and realgar (As2S2, 70.08 As) may
matites,
be both original and secondary minerals, formed usually at shallow

depths, but comparatively unimportant as ores, although considerable quantities of the latter are said to be mined in China (4).
The two occur in some quantity also at Mineral Creek, Lewis
County, Washington.
Native Arsenic, though occasionally found,
is
never in com-
mercial quantities, and the oxides arsenolite and claudetite, of

secondary nature, are likewise unimportant.
Arsenic
is
found combined with a number of metals, or with a
metal and sulphur in

better
known
of these
ore deposits. Among the

occurring in ore deposits of the
many primary
compounds
United States or Canada alone,
may
be mentioned enargite
(CusAsS4), tennantite (CugAs2S7), proustite (Ag6As2Se), smaltite

(CoAs2), niccolite (NiAs), chloanthite (NiAs2), cobaltite (CoAsS),
Of these, the enargite is the second most

sperrylite (PtAs2).
important ore mineral at Butte, Montana.
Great quantities of arsenic are lost annually in this country
by allowing it to pass off with the smelter fumes, and it has been
and
ECONOMIC GEOLOGY
784
estimated that from 14,000 to 15,000 tons of arsenic trioxide are

being set free from the Butte ores every year. Hess states that
other localities in the United States probably supply an additional
5000 tons annually.

Little has been published

United States, and indeed
there appear to be comparatively few discovered deposits of commercial importance. Arsenopyrite has been mined in Washington,
where the mineral is used for making arsenious oxide. The ore
is said to average about 14 per cent arsenic, .7 ounce gold and 3
ounces silver per ton.
In Virginia (9), arsenopyrite has been found at Rewald, Floyd
County. The material occurs as a series of lenses in quartz-
on the occurrence
of arsenic ores in the
the principal lens being 3 feet at the surface, but

thickening to 14 feet at a depth of 120 feet. In Rockbridge
Coanty, in the same state, the arsenopyrite is found in association
sericite schist,
with pyrrte and cassiterite in quartz-greisen-bearing tin veins,
but
not worked.
it is
Arsenopyrite and subordinate pyrite with a quartz gangue,

forming a series of parallel stringers in gneiss, close to a basic
The
dike, is found near Carmel, Putnam County, N. Y. (5).
product of the mine when concentrated averages 25 per cent

arsenic.
A number
of these occurrences are
known but they
are not
White arsenic has been produced
worked.
at
(See references.)
is
since
but
all
the
white
arsenic
as
1901,
Everett, Washington,
made in the West, and the markets are in the East, the product
has to compete with Canadian and other foreign supplies.

White arsenic is made as a by-product in Canada,
Foreign Deposits.
being saved by the smelters at Thorold, Copper Cliff, and Orillia, Ontario,
from arsenical silver ores from Cobalt, Ont.
White
arsenic has been produced at
Uses
of Arsenic.
Mapimi, Mex.
Arsenopyrite is used chiefly for the manuArsenic is employed in medicine, as
facture of arsenious oxide.
a pigment, and as an alloy with lead for making shot. Arsenious

oxide is used for making paris green, in glassware for counteracting the iron coloration, in certain enamels, and as a fixing and
conveying substance for aniline dyes.
weed
killer.
ning,
and
Orpiment
Realgar, the disulphide,
also in pyrotechnics, since

is
it
important as a
used in printing, tanburns with a white light.
It is also
is
used chiefly in textile dyeing.
MINOR METALS
Production of Arsenic.
785
The production and imports from
sources are given below.
PRODUCTION AND IMPORTS OF ARSENIC, UNITED STATES, 1912-1914
YEAR
all
ECONOMIC GEOLOGY
786
REFERENCES ON ARSENIC
1.
Inst. Min. Engrs., Trans. XLVI: 687, 1914.

(Smelter
Hess, U. S. Geol. Surv., Min. Res., 1913: 953, 1914. 3.
4. Hess,
(Brinton, Va.)
Hess, U. S. Geol. Surv., Bull. 470: 205, 1911.
U. S. Geol. Surv., Minn. Res., 1914, Ft. I: 947, 1916. (General.)
6. Richard5. Newland, N. Y. St. Mus.. Bull. 120: 12, 1908.
(N. Y.)
Dunn, Amer.
gases.)
2.
7. Spencer,
(S. Utah.)
son, U. S. Geol. Surv., Bull. 340: 255. 1908.
U. S. Geol. Surv., Bull. 450: 54, 1911. (Llano-Burnet region, Tex.)
8. Spurr, U. S. Geol. Surv., 22d Ann. Kept., Pt, 2: 837, 1901.
(Monte
Watson, Min. Res. Va., 1907: 210. (Va.) 10.

Amer. Jour. Sci., XLII: 403, 1891. (Orpiment and
11. Wells, Ont. Bur. Mines, XI:
realgar, Yellowstone Park.)
101,
See also Cobalt, Ont., refs. under Nickel.)
1902.
(Ont.)
Cristo,
Wash.)
Weed and
9.
Pirsson,
BISMUTH
The
Ore Minerals.
principal ores of this metal, together with
bismuth which they contain, are: Bis81.2); bismite (Bi 2 03, 86.6); and bismutite
percentage of metallic
muthinite (Bi 2 S3,
(Bi 2 C%
C0 2 H 2 0,
,
80.6).
Although
all of
these contain a high
percentage of metallic bismuth, the content of the ore as mined

does not usually exceed ten or fifteen per cent. Native bismuth
is
likewise found at a
number
of localities.
Bismuth ore minerals are almost invariably associated with

other metallic minerals, which are the primary object of mining operations, the bismuth being a by-product obtained in the
treatment of these.
Distribution of Bismuth in the United States.
Very little
United States, and in 1914
the only locality reported producing it, was one in the Clifton
Bismuth occurs in some of
district, Tooele County, Utah.
the Tintic, Utah, lead and copper ores, and is saved at the elecbismuth ore
is
mined as such
in the
lead-refining plant at Grasselli, Ind.

separated at Omaha, Neb. Experiments (1, 3)
trolytic
Some was
also
show that the
dust of Anaconda, Mont., smelter carried 1.15 per cent

tri oxide, and amounted to about 275 tons per year.
This may be saved in the future. Similar quantities might
flue
bismuth
be recovered elsewhere.
Some
carry as
of the gold ores on Breece Hill near Leadville, Colorado,

much as 5 to 8 per cent bismuth, 1 and nearly all of the
gold ores at Goldfield,

1
Nevada
(q.v.),
carry this metal, partly
George Argall, private communication.
MINOR METALS
in
the form of bismuthinite.
787
Other western ores also carry
bismuth.
Foreign Deposits.
are comparatively few.
The deposits of economic value in foreign countries

The mines of Schneeberg, Altenberg, Annaberg
and Johann-Georgenstadt, in Saxony, have contributed considerable bismuth

The bismuth here is chiefly native. At Schneeberg the ores
ore in the past.
are chiefly in cobalt-bearing veins. At Joachimsthal, Austria, the metal
occurs in argentiferous veins. Bismuth as native metal, ochre and carbonate, associated with gold, silver and tin, have been found at Tasna and
Chorolque, Bolivia. The former occurrence is in slates, and the latter in
porphyry. This country is the world's chief source of supply. At Meymac,
France, bismuth ores have been found in veins in granite, together with wolframite and arsenopyrite.
The only Australian colony producing bismuth in any quantity is Queensland.
In New South Wales native bismuth, and bismuthinite associated with

molybdenite in quartz gangue, forms pipes in granite in the Kingsgate district (5).
Uses
Bismuth
on account
forms with lead, tin, and
cadmium; the melting-point of some of these lies between 64 C.
of
Bismuth.
of the easily fusible alloys
and 94.5
C.
They
is
which
chiefly valuable
it
are therefore employed in safety fuses for
electrical apparatus, safety plugs for boilers, dental
and
for automatic sprinklers.
Several
compounds
amalgams,
bismuth
of
are of value in medicine and chemistry.
Production.
The imports
for
consumption of metallic bismuth
into the United States for several years have been as follows:
1912, 182,840 pounds, value
$316,440; 1913, 117,747 pounds,

$213,257; 1914, 90,505 pounds, value $165,208. The
increasing domestic production is reflected in the decreasing
value
WORLD'S PRODUCTION OF BISMUTH

COUNTRY
ECONOMIC GEOLOGY
788
imports, it is claimed. The price of bismuth in the United States

was $2.75 per pound at the beginning of 1915, but by the end of
the year it had risen to $4 per pound.
REFERENCES ON BISMUTH
1.
Min. Engrs., Trans. XLVI: 648, 1914. (Smelter

Amer. Inst. Min. Engrs., Trans. XLVII: 217,
(Rarer metals in blister copper.) 3. Harkins and Swain, Amer.
Dunn, Amer.
fumes.)
1914.
Inst.
2. Eilers,
(Smelter smoke constituents.)

Soc., Jour., XXIX: 992, 1907.
Hess, Chapters on Bismuth in Mineral Resources of U. S. Geological
Survey. 5. Pittman, Min. Res. New South Wales, p. 256, 1901.
Chem.
4.
CADMIUM
The
chief ore mineral of
cadmium
deposits of this mineral are
is
greenockite (CdS),
known, and
it
is
found
but no
chiefly in
Greenockite occurs in the Joplin,

association with sphalerite.
a
as
district
greenish yellow coating on sphalerite,
Missouri,
being a secondary deposit which has been caused by the decomposition of cadmium-bearing blende in the upper part of the ore
body, and the precipitation of the sulphide at lower levels. The
average percentage in
several
thousand shipments from the
was .358 per cent. The table on page 789 gives

the analyses of a number cf samples of Missouri ore and their
cadmium contents.
The calamine ores from Hanover, New Mexico, also contain
cadmium in sufficient quantity to give a yellow tint to the zinc
Joplin district
made from them.

Cadmium has been
oxide
obtained from zinc ores in the United
most
of the output is said to be gained

from bag-house fumes of lead smelters which treat lead ores
States, but at present
containing more or less zinc.
The Silesia zinc regions are the chief source of supply, the
cadmium being obtained as a by-product in the distillation of
zinc.
The domestic production has varied, and is not published.

The imports in 1913 amounted to 1656 pounds, valued at $1232,
and in 1914 to 441 pounds, valued at $368.
Cadmium is used
Uses of Cadmium.
chiefly
by manufac-
turers of silverware, since the addition of only .5 per cent imparts

malleability to the alloy and prevents the formation of blisters.
While cadmium,
like
bismuth, reduces the melting-point of the
MINOR METALS
ANALYSIS OF CADMIFEROUS ZINC BLENDES
(W. George Waring, analyst.)
ORE
789
790
ECONOMIC GEOLOGY
bunches, or in stringers, and is usually a product of magmatic

In most cases the igneous rock is almost completely
segregation.
serpentinized.
The following table gives

Analyses.
several of the types of chromic iron ores
:
the
composition of
MINOR METALS
791
cent of chromic oxide are easily marketable. Low silica is desirable.

The silica permissible in 50 per cent ore is 8 per cent.
In 1915, owing to the war, prices of imported 50 per cent ore

California ore ranged
rose to $25 to $35 per ton in large lots.
from $11 to $18 per ton f.o.b.
Chromite
(s)
of
in
an
little
the
United
importance
industry
very
mining
the
are
because
deposits,
States,
though widespread,
rarely of
workable size. Deposits are known in Maryland, Pennsylvania
(11, 12), North Carolina (7), Wyoming and California (4, 5).
The ore was at one time obtained from Chester and Delaware
counties, Pennsylvania, and Baltimore County, Maryland, but
these are no longer worked. Chromite sand is, however, obtained
from stream deposits within the chromiferous serpentine area of
Distribution of Chromite in the United States
is
Maryland.
California
5)
(4,
contains a
number
chromic iron
of
ore
and closely related
deposits, scattered through the serpentine

intrusive rocks of the Coast
NW.
Range and the Sierra Nevada,
SE.
but the production from these

usually small, as the transcontinental
transportation
is
problem
The
County
J
is
a serious one.
(Fig. 279)
Shasta
which have
of
deposits
,
in recent years attracted the

most attention, occur in a
mass
of serpentine and allied

In one of these (Fig.
rocks.
280)
feet
an ore body about 25

wide and 100 feet long is
,-,
FIG.
Section of
280.
iron
Brown
chromic
ore
mine, Shasta County, Calif,

a. Pyroxenite, in some places saxonite
or dunite; 6, lean ore granular groupsof chromite in pyroxene and olivine;
c,
ore
richer
and olivine
in
(?)
chromic chlorite.
chromite,
pyroxene,
altered to chlorite
and
(After Diller.)
found.
The Canadian production is generally

to occur in the serpentine rocks of
are
known
Deposits
the Quebec asbestos area (see p. 302), where they form irregular
or lens-shaped bodies of workable size and also nodules and
Canada
(3,
2)
small.
grains disseminated through the serpentine and pyroxenite.

Alaska (l).
Chromic iron ore is said to occur as a lode
Chatham on Kenai Peninsula, and chromite

have
also
been found in the gold placers of Shungnak
fragments
in the upper Kobuk basin.
deposit near Port
ECONOMIC GEOLOGY
792

The principal foreign sources of chromite,
and of the world are New Caledonia, Rhodesia, Turkey in Asia, and Greece,
but during the war most of these have been practically closed to the United
States.
New
The ore in the southern part of the island occurs as

masses in ferruginous clay, and as veins and irregular masses in
serpentine. That found in the northern part of the island is more important,
Caledonia.
rich, soft,
run 67 per cent Cr 2 O 3

The ore occurs in talc
This is an important producer.
schist and serpentine, usually as disseminations, but at times forming massive lenses which range from 150 to 450 feet in length. 2
In Turkey in Asia, the chromite ore occurs in serpentine,
Turkey.
while that of Greece is associated with both basic rocks and limestone.
Interesting but not very important deposits are found in Norway, at
and
may
Rhodesia.
Mount Dun
is
;n
found
also
New
in the
3
Zealand, and at Kraubat in Styria (Fig. 135).
Cuban
Some
iron ore deposits.
chromium has no
direct use but raw chromite

have a variety of applications. Owing to its
great heat-resisting qualities, chromite is employed in the manufacture of refractory bricks.
Such bricks are sometimes used for lining
basic open-hearth furnaces, and as a hearth lining for water-jacket
Uses.
Metallic
and chromium
salts
furnaces in copper smelting.

They stand rapid changes of temperature well, and are not attacked by molten metals.
In the presence of carbon, chromium makes steel extremely hard
and resistant to shocks therefore chrome steel is suited to a variety
;
manufacture of plates, hard-edged tools, etc. An

allojr of iron and chromium is used in armor plates, alloys of ferrochromium and ferronickel being added to the molten steel before
casting. Most of the chromite mined is used for pigments because
of the red, yellow, and green color of its compounds, chromate and
bichromate of potash. In these forms the substance is employed
in dyeing, calico printing, and the making of pigments useful in
Alkaline
painting, printing wall papers, and coloring pottery.
bichromates are employed for tanning skins, and some chromium
salts have a medicinal value.
of uses, as in the
Production of Chromite.
The amount of chromite produced
United States is small, and California has usually been
the only source of supply, although Wyoming produced a small
in the
amount
1
2
3
in 1908
and 1909, and Maryland
The United
in 1914.
Imp. Inst., VIII, Nos. 3 and 4, 1910.

Min. Mag., Feb., 1915.
Vogt, Krusch and Beyschlag, translation by Truscott,
Bull.
244, 1914.
MINOR METALS
793
States production in 1914 was 591 long tons, valued at S8715,

or $14.75 per ton, but in 1915, owing to war conditions, it rose
to 3281 long tons, valued at $36,744.
The world's production in part, is as follows: New Caledonia (1913), 62,352 long tons; Rhodesia (1913), 62,365 long
tons; Russia (1912), 20,934 long tons.
The imports into the United States in 1914 were as follows:
Chromic iron
chromic
ore, 80,736 long tons, value $695,645;
9164 pounds, value $1597; chromate and bichromate of
potash, 31,858 pounds, value $2375.
Canada in 1914 produced 136 short tons of chromite, valued
at $1210, but in 1915 the production amounted to 14,291 short
acid,
tons, valued at $208,718, ore averaging
from 30 to 35 per cent
finding a ready market.
REFERENCES ON CHROMIC IRON ORE

1.
2. Camsell,
Brooks, U. S. Geol. Surv., Bull. 592 : 36, 1914.
(Alaska.)
Can. Geol. Surv., Mem. 26 : 56, 1913.
3. Cirkel, Can.
(B. C.)
Dept. Mines, Mines Branch, No. 29, 1909. (Quebec.) 4. Diller,
U. S. Geol. Surv., Min. Res., 1914 and 1915. (Calif.) 5. Dolbear,
Min. and Sci. Pr., CX 356, 1915. (Calif.) 6. Maynard, Amer.

Min. Engrs., XXVII: 283, 1898. (N. F.) 7. Pratt and Lewis,
N. Ca. Geol. Surv., I: 269, 1905. (Origin.) 8. Harder, U. S. Geol.
9. Anon., Cal. State Ming. Bur.,
Surv., Min. Res., 1908. (U. S.)
Bull. 38: 266. (Calif.)
10. Mathews, Md. Geol. Surv., Rept. on
Cecil County.
11. Rogers and others, Second Pa. Geol.
(Md.)
12. Hall, Second Pa. Geol. Surv.,
92.
(Chester Co.)
Surv., C 4
C 5. (Delaware Co.) 13. Emerson, U. S. Geol. Surv., Atlas Fol. 50,
1898.
(Chester, Mass.) 14. Dresser, Can. Geol. Surv., Mem. 22 (Que.)
:
Inst.
MOLYBDENUM
Ores and Occurrences.
Molybdenite (MoSg) and, less commonly, wulfenite (PbMoO4) are the chief sources of this metal.
Molybdenite may occur as a constituent of pegmatite veins;
it also forms irregular masses or disseminations in crystalline
rocks, and many occurrences are known in the West, for example,
in California, Washington, Montana, Utah, Arizona, New Mexico,
in the East, in Maine (4)
Wulfenite is found in the oxidized
zone of lead ores in a number of western states. Numerous
references to different occurrences are found in the Mineral
and
Resources
issued
by the United
States
Geological
Survey.
ECONOMIC GEOLOGY
794
Several
Nova
occurrences
Scotia
have been described from Quebec and
(7).
Marketable molybdenum ores should carry at least 25 per

cent molybdenum oxide and be free from copper, vanadium,
tungsten and chromium.
The
Uses.
"
chief use of
and
molybdenum
is
in
making
"
this apparently caused its price to rise
high
from
steels,
speed
20 or 30 cents a pound in 1912, to $2 a pound in 1914. Ammonium molybdate is a chemical reagent. Metallic molybdenum
used in resistance furnaces, as supports for filaments in electric

incandescent lamps, as parts of Roentgen ray tubes, and as one
of the alloying metals in stellite.
is
is
The production of molybdenum

Production of Molybdenum.
small, but there was a greater demand for it in 1914.
REFERENCES ON MOLYBDENUM
1.
Andrews, N. S. W. Geol. Surv., Min. Res. No. 11, 1906. (N. S. W.)
2. Cameron, Queensland Geol. Surv., Kept. 188, 1904.
(Queensland.)
3. Crooks, Bull. Geol. Soc. Amer., XV
(N. Y.) 4. Sm th,
283, 1904.
U. S. Geol. Surv., Bull. 260 197, 1905. (E. Me.) 5. Hess, U. S.
Geol. Surv., Bull. 340 231, 1908.
6. Basker(Me., Utah, Calif.)
7. Walker, Dept.
ville, Eng. and Min. Jour., LXXXVI
1055, 1908.
Mines Can., 1911. (Can.)
:
NICKEL AND COBALT

Ore Minerals.
These two metals can best be treated
to-
gether, for nearly all the ores containing the one are apt to carry
some of the other, and furthermore, in smelting, the two metals
go into the same matte, and are separated later in the refining
process.
The
ore minerals of nickel
and
cobalt, of recognized occurrences,
together with their composition and the percentage of nickel or

cobalt they contain, are shewn in the table on page 795. Of
these some occur only in small amounts as millerite, pentlandite,
genthite,
The
and chloanthite.
nickeliferous pyrrhotite
is
the most widely distributed
of the economically important nickel ore minerals and may carry

small amounts of cobalt.
It is also called magnetic pyrites."
The percentage of nickel ranges from a trace to 6 per cent, but

an increase above this brings it mto pentlandite. Millerite is
sometimes found associated with pyrrhotite ores.
MINOR METALS
OKE
795
ECONOMIC GEOLOGY
796
The only production in 1907 was near Prairie City, Grant County, Oregon,
but tie deposits which have attracted the most attention from time to
time are those of Piney or Nickel Mountain near Riddles (8), Douglas County,
in the
same
The
ore,
state.
which
is
genthite in a quartz gangue, occurs a3 flat-lying deposits
en the surface of post-Cretaceous pre-Eocene peridotite, or as veinlets in

The former deposits occur as brecciated
the peiidoiite and serpentine.
and conglomeratic masses, and consist of silica, nickel silicate, ferric oxide,
and serpentine with very subordinate chromite. Prolonged wea hering
cases has removed the nickel.
thought that the genthite represents a decomposition product of the
The hydrated nickelperidotite, for nickel is found in the fresh rock.
magnesian silicates and silica formed by weathering were subsequently in
in
some
It is
part dissolved and carried down into crevices of the underlying peridotite.
Such a theory limits the depth. If formed by ascending hot waters, as
some believe, a greater depth would be assured.
Nickel occurs in a great many blister coppers, and the quantity reported in various ones in pounds per hundred tons
was as
Anaconda, Mont., 22; Great Falls, Mont.,

Nev., 64;
Omaha, Neb.,
68; Garfield, Utah, 40; Steptoe,
Tacoma, Wash., 770; Aguasca944; Mountain, Cal., 172;
Cerro de Pasco, Peru, 32; Mount Lyell,
lientes, Mex., 132;
166.
Tasmania,
The
follows:
electrolytic refining of these coppers has yielded consider-
able nickel.
Canadian Occurrences.
Canada is the most important source
nickel and cobalt ores in North America, and indeed
in the world, but much of the mine production is shipped
to the United States for treatment and consumption.
It is
therefore of interest to refer to the two important producing
localities, viz., Sudbury and Cobalt, both in the province of
of the
Ontario.
Sudbury, Ontario
(2,
3,
4,
5,
8a).
This district
is
the main
source of supply for the nickel used on this continent (Fig. 281).
The geological formations present in the region according to
Coleman
(5)
are as follows:
Paleozoic?
Sand and clay.

Diabase and granite
Keweenawan.
Sudbury nickel-bearing eruptive.
Pleistocene.
Animikie or
Upper Huronian.
dikes.
Chelmsford sandstone.
Onwatin
slate.
Onaping tuff.
Trout Lake conglomerate.
MINOR METALS
Lower Huronian.
797
Laurentian.
Conglomerate.
Granitoid gneiss and hornblende
Sudbury
Chiefly
series.
schist.
quartzite, also acid and basic eruptives.

Equivalent (?) to Temiskaming of Cobalt area.
Quartzite, and fine-grained gray gneiss and schist.

Chiefly greenstone and greenstone schists.
Grenville series.
Keewatin.
SCALE OF MILES
50
40
30
20
10
50
FIG. 281.
Map
of Cobalt
Porcupine
Sudbury
KILOMETRES
region.
(Out. Bur. Mines.}
ECONOMIC GEOLOGY
798
Reference to the section (Fig. 283)

bearing laccolith
will
show that the
appears to rest on ancient crystallines
nickel-
and
is
covered by metamorphosed Animikie sediments; that, moreover,
FIG. 282.
Geologic
map
of Sudbury, Ont., nickel district.
(After Coleman.)
the underlying and overlying formations are bent into a great
canoe-shaped trough or basin.
The
part,
intrusive where fresh is a norite on its outer border or lower

and passes by insensible gradation into a granite on its
inner edge (Fig. 283).
FIG. 283.
The
Geologic section of Sudbury, Ont., nickel
district.
(After Coleman.)
ore bodies are found at or near the margin of this great

which covers over 500 square miles.
laccolithic sheet,
Coleman
believes that following the eruption of the nickelbearing magma there was a long-continued process of segregation,
resulting in an accumulation of the more basic elements of the
MINOR METALS
molten mass in
its
lower part, and the more acid elements in
799
its
upper portion, the sulphides sinking into the depressions of the

Archaean substratum. The collapse of the underlying Archaean,
due to the upflow of the magma from underneath, is supposed to
have caused a sinking of the overlying rocks, and formation of the
The ore bodies occur only in the norite, around its

margin, or in some of the dike-like offsets.
The ores, which are of remarkably uniform character, consist
trough.
mainly of pyrrhotite, chalcopyrite, and pentlandite, and though

the last is important, it is rarely visible to the naked eye. Variations in the proportions of these three may, however, occur.
Thus, in the Copper Cliff mine, the percentages were 4.65 Cu to
Ni one year, while in another they were 7.81 Cu to 2.37 Ni.

The ore bodies are sometimes found on the margin of the
eruptive, and have a foot wall of the older rocks, but an ill-
4.46
These form irregular sheets dipping todefined hanging wall.

wards the synclinal axis. Others, of irregular shape, are found
in the dike-like projections of the basic edge.
Several theories have been advanced to account for the origin of

Coleman and others believe that the ore is of
tkese ore bodies.
magmatic origin because they claim (1) it is everywhere associated

with norite, and grades into it, (2) the adjoining rocks are never
spotted with ore, and separated bodies of ore are never inclosed
:
them, but veinlets of ore may penetrate them, (3) there is little
evidence of hydrothermal or pneumatolytic action, such as one
might expect if the deposits were other than magmatic segregain
and
offsets, which represent

into
and
which the ore would
laccolith.,,
a
settle.
who
also
made
somewhat careful
naturally
Barlow,
of
this
concurs
with
Coleman
study
district,
regarding the origin
tions,
(4)
the largest bodies are in the
the lowest portions of the
of the ore by magmatic segregation.

It is, of course, not improbable that the ore bodies have been rearranged somewhat later by
circulating water.
At some variance with these views are those expressed by Dickson
(6)*
His theory
is
that the ore occurs as a cement for brec-
ciated rock fragments and along shearing planes which are of premineral age, the ore minerals having been deposited by solutions
and by a process of replacement, This view seems to be confirmed

by the examination of the minerals of this district by metallographic methods, which show the following order of succession:
(1)
Magnetite,
(2)
silicate,
(3)
pyrrhotite, (4) pentlandite, (5)
ECONOMIC GEOLOGY
800
And following a long line of investigators, Knight

presents most interesting evidence to show that the ores
have been deposited from solution. He points out that the
chalcopyrite.
(8a)
granite floor of the laccolith is younger than the norite because

it sends dikes into it, and that the ore is found not only in the
but also in the graywacke and the granite, and concludes

solutions
that
rising along the granite norite contact deposited
norite,
the ore.
According to Cole man, the percentage of sulphides in the ores

varies from 50 to 80, while the nickel contents ranges from 1.5 to
5 per cent. The cobalt is present in amounts varying from -^ to
-j^j of the nickel present.
An
25.92;
analysis of a high-grade matte gave:

Fe, 2.94;
Irid., .02;
Cobalt,
Os, .02;
Ontario
S, 22.50;
Rh and
NiCo, 48.82;
Ag, 3.14 oz.;
Cu,
Pt, .13;
Pal., tr.
The
(10).
.02 oz.;
An,
silver-cobalt-nickel
veins
found
at this locality present one of the most remarkable series of ore

deposits found in recent years, and have their analogue only in
certain foreign occurrences.
The
district lies
near the boundary of
the provinces of Ontario and Quebec, and west of the northern end
Lake Temiskaming (Fig. 281).

The ores occur in mostly well-defined veins which range from
less than an inch to as much as a foot or more in thickness, and
of
occupy narrow, almost vertical fissures or joints, cutting through

a series of slightly inclined metamorphosed fragmental rocks of
Lower Huronian Age. Some are also found in the diabase and
Keewatin, although these
The
last
two are never
geological section at this locality
is
so productive.
as follows:
Glacial drift.
Silurian.
Niagara limestone.
Great unconformity.
Pre-Cambrian.
Later dikes of aplite, diabase and basalt.
Nipissing diabase, probably of Iveweenawan age.
series.
Conglomerate, greywacke, and other fragmentals.
Cobalt
Unconformity.
Lorrain granite.
Lamprophyre dikes. Near some of mines.

Temiskaming series. Conglomerate and other fragmental rocks.
Keewatin complex. Includes basic volcanics, now altered to
and greenstones; also altered sediments including jaspilyte,
and greywacke.
schists
slates,
MINOR METALS
801
The
veins are narrow, practically vertical fissures and jointthe Cobalt series.
few productive ones are
found in the Nipissing diabase and in the Keewatin (Fig. 284).
like cracks, cutting
Most
of the ore has come from veins or parts of veins that

originally lay beneath the sill.
The important ores are native silver, smaltite, and cobaltite,
but associated with them in varying quantities are niccolite,
chloanthite, millerite, argentite, dyscrasite, pyrargyrite, arsenopyThe oxidized zone, which is usually but a few feet in
rite, etc.
X^^^^m^ ^~^^^'^
I
Diabase
%%m Keewatin
FIG. 284.
/'^^Lin^'K^V^'^
^^^^^^^^^^^^^^^^^-'^^^^^
Cobalt Series
Veins
Hypothetical Veins
Generalized vertical section through the productive part of the Cobalt

Ont., area.
The section shows the relations of the Nipissing diabase sill to the Keewatin
and the Cobalt series, and to the veins. The eroded surface is restored in the
B and C- represent
section, and the sill is less regular than the illustration shows.
a large number of veins that are in the fragmental rocks, Cobalt series, in the foot
wall of the eroded sill;
represents a type of vein, in the Keewatin below the
eroded sill; L a vein in Keewatin footwall, but not extending upward into the
a vein in the sill itself; T a vein in Keewatin hanging wall and extending
sill;
downward
into the
sill.
(After Miller, Ont. Bur. Mines,
XIX,
Ft, II, 1913.)
depth, shows native silver, erythrite (cobalt bloom), and annaCalcite is the chief gangue mineral,
bergite (nickel bloom).
quartz being much less common.

W. G. Miller (10), who has given more careful study to this
region than any one else, believes that the ore was deposited by
highly heated impure waters circulating through cracks and fisThe
sures following the post-middle Huronian diabase eruption.
metals may have been brought up by these waters from a great
depth, or they may have been leached out of the now folded and
disturbed greenstones and other Keewatin rocks. He inclines
ECONOMIC GEOLOGY
802
to the theory, however, that the diabase magma was the source of
both the cobalt-nickel minerals and the silver.
The cobalt arsenides were probably the first minerals deposited,

and this was followed by a slight disturbance of the veins, resulting in the formation of cracks and openings in which the silver and
later minerals
were deposited.
disturbance contained no
Veins which escaped this latter

Many of the veins of this
silver.
but all are not so. As an example

an open cut on the Trethewey vein, 80 feet long and
deep, yielded $200,000 of ore from an 8-inch vein. A
district are fabulously rich,
of the former,
25 feet
FIG. 285.
Section of calcite, and native silver, the latter in part replacing the
former.
X30.
Cobalt, Ont.
shipment of 80 tons of this ore gave approximately: As, 38 per

cent; Co, 12 per cent; Ni, 3.5 per cent; and 190,000 ounces
silver.
Pay was received only for the cobalt and silver.
The veins at Cobalt are unique among North American ones,
but resemble those of Annaberg, Joachimsthal, and other localities,
referred to below.
The
discovery of these deposits was
made
in building the
Temiskaming and
railroad, and their development has made Ontario one of the

leading silver producers of the world.
Moreover, it practically controls the
world's supply of cobalt, and the arsenic shipped from the Cobalt camp
Northern Ontario
equals about one-half of the world's production, but much of it is not saved.
Milling plants have recently been installed for concentrating the lower grade
The ores are treated in part in the United States, but there are now
ores.
plants erected for this purpose at Copper Cliff, Deloro, and Thorold, Ontario.
MINOR METALS
803

Deposits of nickeliferous pyrrhotite in basic
eruptive rocks are known at a number of localities in Norway, ,the ore
1
Deposits of a similar type are
averaging 1.5 to 2.5 per cent nickel.
known in Italy, Spain, and Russia, but they are of little economic importance.
Next to Sudbury, New Caledonia is the most important source of nickel
in the world. 2 The island consists of ancient schists and Mesozoic sediments, pierced by eruptives, especially peridotite. The latter is more or
less altered to serpentine.
garnierite.
They occur
The
ore minerals
as veinlets
are hydrated silicates, chiefly

in the ser-
and concretionary masses
pentine and peridotite. There are also green siliceous masses carrying 9 to
10 per cent nickel. Most of the ore is low-grade, averaging 7 per cent
nickel after drying at 100 C.
Deposits of cobalt-silver ore similar to those of Cobalt, Ont., are found in

The ores of these
viz., Joachimsthal and Annaberg.
Germany and Austria,

two
include compounds of cobalt, nickel, bismuth, and silver, and

uranium, which has not been found in the deposits of Cobalt,
districts
in addition
Ontario.
At Joachimsthal, Bohemia, there is a series of mica schists, calc schists,

and limestones cut by dikes of basalt. The veins, which antedate the
basalt, but cut the other rocks, are narrow, often brecciated, and contain
hornstone, quartz, calcite, and dolomite as gangue material. Various silver,
nickel, cobalt, bismuth, and arsenic minerals are present, as well as lead,
3
The cobalt and
zinc, iron, and copper sulphides, together with uraninite.
nickel ores are generally the older, and the silver ones younger.
At Annaberg, Saxony, the veins occur in gray gneiss. There are two
groups, the younger and most important carrying silver-cobalt ores, with
nickel and bismuth in a gangue chiefly of barite, fluorite, quartz, and brown
spar. The older veins carry tin and lead.
The veins
at Schneeberg, Saxony, occur in contact-metamorphic clay

slates, but become poorer on passing into the underlying granite.
The ore minerals are smaltite, chloanthite, niccolite, bismuthinite, and
native bismuth in a gangue of quartz, hornstone, calcite, and dolomite.
Silver minerals are rare.
New
South Wales was formerly the second largest world's producer
of
cobalt. 5
The most important and increasing use of

manufacture of nickel and nickel chromium
This, on account of its great hardness, strength, and
Uses of Nickel.
nickel
steel.
is
for the
Vogt, Krusch and Beyschlag, Translation, I.

Glasser, Ann. de Mines, 15th ser.,Tome IV; 299 and 397, 1903; Colvocoresses,
Eng. and Min. Jour., LXXXIV: 522, 1907.

3
Vogt, Krusch und Beyschlag, Lagerstatten,
Bur. Mines,
4
and
5
XIX,
II: 173, 1912.
Also Miller, Ont.,
Pt. II: 213, 1913.
Vogt, Krusch und Beyschlag, Lagerstatten, II: 173, 1912; Dalmer, Kohler,
Karte Sachsen, 1883.
Pittman, Mineral Resources, New South Wales, N. S. W. Geol., Surv. 1901.
Milller, Section Schneeberg, Geol. Spez.
ECONOMIC GEOLOGY
804
used for making armor plate, gun shields, turrets,

ammunition, hoists, etc. Krupp steel, which may be taken as a
type, has approximately 3.5 per cent nickel, 1.5 per cent chromium,
and .25 per cent carbon. Owing to its abrasive resistance, nickel
Other important uses are for
steel is now much used for rails.
large forgings, marine engines, wire cables, and electrical apparaA steel with 25 to 30 per cent nickel shows high resistance
tus.
elasticity, is
to corrosion
German
metal
is
by
silver
salt, fresh or
is
an alloy
acid waters, or
by superheated steam.
and nickel. Monel
of zinc, copper,
an alloy containing 68 per cent
nickel, 1.5 per cent iron,
and 30.5 per cent coppe/.

Cobalt steel, while having a high elastic
Uses of Cobalt.
limit and breaking strength, cannot compete with nickel steel
on account of its high cost, and the main use for cobalt is as a
Stellite is an
pigment, it being used to color glass and pottery.
of
chromium
and
other
metals.
cobalt,
alloy
Nickel ores were not mined in the United States in either 1913
or 1914, but in the latter year the equivalent of 845,334 pounds of
metallic nickel, valued at $313,000, is said to have been saved as
a by-product in the electrolytic refining of copper.

one-third to one-half of this came from domestic ore.
Probably
The United
States is the largest nickel refining country of the

of
most
the metal being derived from Canadian matte, and
world,
some indirectly from New Caledonia. The total imports of nickel
alloys, pigs, etc., ore and matte (nickel content), and nickel oxide
imported into the United States in 1914 amounted to 35,098,958
The exports of nickel and nickel
pounds, valued at $5,000,594.
oxides from the United States in 1914 amounted to 27,595,152
pounds, valued at $9,455,528.

Canada in 1914 produced 46,396 short tons of matte, valued
and containing 28,895,825 pounds of copper, and

There is also a small recovery of
45,517,937 pounds of nickel.
nickel in the form of nickel oxide from the Cobalt district ores,
at $7,189,031
the production in 1914 being reported as 391,312 pounds of oxide

valued at $26,483.
The exports
in 1914
amounted to 46,538,327 pounds
of nickel
in matte.
Production of Cobalt.
States in 1914.
No
The imports
cobalt was produced in the United

into the United States of cobalt
oxide, cobalt ore, and zaffer (an impure cobalt oxide),

to 334,556 pounds, valued at $274,538.
amounted
MINOR METALS
805
REFERENCES ON NICKEL AND COBALT

1.
(Ontario.)
Barlow, Can. Geol. Surv., Ann. Rept. XIV, Pt. H, 1904.
2. Barlow, Econ. Geol., I:
(Sudbury.) 3. Browne,
454, 545, 1906.
Econ. Geol., I: 467, 1906. (Sudbury.) 4. Campbell and Knight,
Econ. Geol., II: 351, 1907. (Microstructure of nickeliferous pyrrho5. Coleman, Can. Dept. Mines., Mines Branch, No. 170, 1913.
tites.)
(Nickel Industry. Also Ont. Bur. Mines, Ann. Rept. XIV, Pt. 3.
(Sudbury.) 6. Dickson, Amer. Inst. Min. Engrs., Trans. XXXIV:
7. Hodges, Amer. Inst. Min. Enjrs., Trans.
1904.
(Ontario.)
3,
XIII: 657, 1885. (Mex.) 7a. Kalmus, Can. Dept. Mines, Mines
Branch, No. 309, 1914. (Properties of cobalt.) 8. Kay, U. S. Geol.
8a. Knight, Eng. and Min.
(Ore.)
120, 1907.
Surv., Bull. 315:
(Sudbury.) 9. Kemp, Amer. Inst. Min. Engrs.,
Jour., CI: 811, 1916.
10. Miller, Ont. Bur. Mines, XIX,
Trans. XXIV: 620, 1895.
(Pa.)
Pt.
II,
1913.
Trans. XIII:
11. Neill,
(Cobalt, Ont.)
12. See
(Mo.)
634, 1885.
13.
Resources, U. S. Geological Survey.
Bull. 528, 1913.
(Lemhi County, Ido.)
1907: 578.
Ainer.
Inst.
Min
Engrs.,
annual reports on Mineral

Umpleby, U. S. Geol. Surv.,
14. Watson, Min. Res. Va.,
(Va.)
PLATINUM GROUP OF METALS

The
Platinum.
ore minerals of platinum are native platinum

PtAS 2 (56.5 per cent Pt). The
(100 per cent Pt) and sperrylite,
former
is
occurrence
commonly found
is
in placer deposits, but its original

in associations with chromite in peridotite, or in
it, although such deposits are nowhere

found in workable quantity. Sperrylite never occurs in large
quantities, but is found in association with sulphide minerals in
Where occurbasic igneous rocks such as gabbro and diabase.
in
a
rocks
it
represents
crystallization product of
ring
igneous
serpentine derived from
the
magma.
In addition to these two types of occurrence platinum has also

been found in quartz veins as in Nevada (p. 806), Canada, 1
Finland
and
New
Zealand, and
also
in
at
(Sumatra) in a contact-metamorphic deposit.

osmiridium are also known to carry platinum,
least
one case
Tridosrnine
and
it
and
also occurs
as an alloy with other members of the platinum group.

Most of the world's supply of platinum is obtained from
placer deposits.
The nuggets found in placers are commonly regarded as being

pure native platinum, but this, according to Kemp (5), is only
true in part, most of those assayed yielding between 70 and 85
'Bell, Econ. Geol. I:
749, 1906.
ECONOMIC GEOLOGY
S06
per cent, and the richest recorded being 86.5 per cent. The
balance is made up largely of iron, the highest percentage of this
noted being 19.5 per cent in a Ural specimen. Iridium, rhodium,
Until the platinum falls
present.
reaches
5 per cent, rhodium
iridium
the
cent
60
below
rarely
per
4 per cent, while palladium is less than 2 per cent. Other elements that have been detected in the nuggets are osmium,
and palladium are always
ruthenium, copper, and even gold, while chromite

associated mineral (o).
is
common
The domestic supply of

obtained from gold-placer deposits in
Oregon and California, and while its occurrence has been reported
in many other gold placers of the Northwest and Alaska, still none
platinum, never large,
is
them have proven sufficiently rich to work. Most of the Calicomes from the dredges at Oroville, in Butte
County. The platinum is usually panned from the black sand,
of
fornia production
but a small quantity
and recovered
alloy of iron
entangled with the amalgamated gold

Iridosmine and a natural
is
in refining at the mint.
and nickel
called josephinite are
found associated
with the gold.

In addition to the above sources, platinum is also found in the
copper ores of the Rambler mine, Wyoming, and has been saved
from the slimes obtained
The
in treating the
covellite in the ore
copper ore and matte at
said to assay .06 to 1.4

ounces per ton of platinum.
A remarkable find of platinum and palladium was made in
1914, in the Yellow Pine mining district of Clark County, Nev.
this locality.
(6).
is
According to Knopf the deposit consists of a fine-grained

mass, irregularly replacing Carboniferous limestone
quartz
along a series of vertical fractures. A dike of granite porphyry

found not far from the ore body, but no basic intrusives are
is
known
in the district.
The
ore bodies developed are oxidized
copper shoots and gold-platinum-palladium shoots, the latter

consisting of a fine-grained quartzose ore containing a small
amount of a bismuth-bearing variety of plumbojarosite (6).

The ore averaged in ounces per ton: gold, 3.46; silver, 6.4;
platinum, .70; and palladium, 3.38. The deposit differs greatly
from any known deposit carrying platinum metals, and is further
remarkable because of
deposits in
its
probable genetic connection with acid
Moreover the lode is one of the few primary

which platinum metals occur in more than traces.
igneous rocks.
807
In the nickel deposits of Sudbury, Ontario
Canada.
(p. 796),
accompanied by palladium probably also as

arsenide, is found, the Bessemer mattes carrying from .17 to .5
Platinum has also been found
ounce of the platinum metals.
in the dunites of the Tulameen district, British Columbia, but
toot in commercial quantities.
platinum arsenide,
The platinum placers of the Urals in Russia

form the most important source of the world's supply, the two principal
centers of production being Blagodat on the Asiatic slope, and Nizhni1
Second in importance is Colombia,
Tagilsk, on the European slope.
the
Choco and its tributaries. Like the
are
worked
where placers
along
Russian placers, the platinum is obtained in greater proportion than gold. 2
Platinum was first used as an adulterant of gold, and

was used for coinage from 1823 to 1845.
At the
present time it is employed for crucibles and other chemical
apparatus which are to be subjected to high temperatures or
Uses.
in Russia
it
It
strong acids.
is
also of value in dentistry, for electric
lamps
apparatus, for jewelry, and in photography. An

important use is as a catalyzer in what is technically known as
"
"
in the manufacture of fuming sulphuric acid
contact mass
and
electric
and sulphur
The price of it has risen

more valuable than gold.
trioxide.
years, so that
it is
steadily in recent
A considerable output of platinum is annually

United States from the refining of gold and copper
bullion of both domestic and foreign origin.
Production.
made
in the
WORLD'S PRODUCTION OP
NEW
IN
Country.
PLATINUM IN 1913-1914, BY COUNTRIES,
TROY OUNCES
ECONOMIC GEOLOGY
808
In 1914, California produced 463 ounces of crude platinum

(about 80 per cent fine), and Oregon 107 ounces (about 70
per cent fine), the total value of these being $18,240. The
total quantity of refined platinum produced in the United
States in 1914 was 3430 ounces.
During 1914 the average price of refined metals

group, per troy ounce was: platinum, $45;
of the
platinum
iridium,
$65;
palladium, $44.
The imports of platinum, both crude and manufactured,
into the United States in 1914 had a total value of $2,908,353,
as compared with $5,040,210 in 1913, the decrease being due to
iridosmine (osmiridium), $33;
the unsettled conditions abroad.

is found associated with platinum
and alloyed with gold (Brazil). It is of silverwhite color, ductile and malleable, and is unaffected by the
air.
Its great rarity and consequent high value has restricted its
but
a small amount is used for some mathematical and surgical
use,
instruments, for compensating balance wheels and hairsprings
for watches, and for finely graduated scales.
In the United States it has been reported from the platinum deposits of the Pacific coast and from the Rambler mine in Wyoming.
Osmium.
This, the heaviest and most infusible metal known,
occurs alloyed with platinum and also with iridium in iridosmine.
In the United States small quantities have been found in the
platinum placers of California. It is also obtained from Tasmania (10).
Iridosmine is employed for pointing pens and fine tools, while
This metal
Palladium.
and
also native
osmic acid
is
scopic work.
Iridium.
used for staining anatomical preparations in micro-
found chiefly in Russia and California,

osmium. It is a lustrous, steel-like
metal of great hardness, and is, next to osmium, the most refractory metal known.
Iridium
is
"
alloyed with platinum or
An
alloy of iridium
and platinum has been used
weights and measures, and iridium
is
for standard
also used in photography.
REFERENCES ON PLATINUM
1.
Day, U. S. Geol. Surv., 19th Ann. Kept., VI: 265, 1898. 2. Day, Amer.
Inst, Min. Engrs., Trans. XXX: 702, 1901.
3. Camsell,
(N. Amer.)
Can. Min. Inst., XIII: 309, 1911. (Tulameen, Brit. Col.) 4. Donald,
Eng. and Min. Jour., LV: 81, 1893. (Can.) 5. Kemp, Min. Indus.,
X: 540, 1902; and U. S. Geol. Surv., Bull. 193, 1902. (General.)
MINOR METALS
809
Knopf, U. S. Geol. Surv., Bull. 620, 1915. (Yellow Pine district,

Nev.) 7. Perrett, Trans. Inst. Min. and Met., XXI: 647, 1912.
8. Purington, Eng. and Min. Jour., LXXVII:
(Russia.)
720, 1904.
6.
9. Day and Richards, U. S. Geol. Surv., Bull. 285:

(Russia.)
150,
1906.
(Platinum in black sands.) 10. Twelvetrees, Tasmania Dept.
Mines, Geol. Surv., Bull. 17, 1914. (Bald Hill osmiridium field.)
SELENIUM
This rare and little-known element, which forms not over
known rocks, is not known to occur in
even
though it forms combinations with a
deposits by itself,
number of other metals, which are found in nature. It is found
.0002 per cent of the
in
some gold, silver and copper ores.

Thus Spurr has called attention
ores of
its presence in the gold

found, at least in part as
associated with gold in the Republic
Tonopah, Nevada, where
silver
selenide.
It
is
to
it is
district of
Washington (e).
Selenium in some form also occurs in nearly
bearing sandstones of Colorado and Utah.
Pyrite ores
may
also carry
all
the vanadium-
it.
The commercial supply of the United States, however,

nished by the electrolytic copper refineries, as nearly all
is
fur-
blister
copper contains it.

The 1914 United States production, saved in copper refining,
was 22,867 pounds, valued at $34,277.
Uses.
used as a red colorant of glass, while

enamels used for covering steel.
Owing to its low electrical conductivity in the light,
and higher conductivity in the dark, selenium wire is used in
Selenium
is
selenite of soda gives a bright red color to
automatically lighting and extinguishing gas buoys.
REFERENCES ON SELENIUM
Amer.
Min. Engrs., Trans. XLVII: 217, 1914. (Selenium,

2. Gale, U. S. Geol. Surv., Bull. 340:
261,
1908.
3. Hess, U. S. Geol. Surv., Min. Res.,
(In U and V ores.)
4. Hillebrand, et al., Amer. Phil. Soc., Proc. VIII:
1914.
(General.)
(Native selenium, Utah.) 5. Joseph, Eng. and Min. Jour.,
34, 1914.
LXVIII: 636, 1899. (Republic, Wash.) 6. Lindgren and Bancroft, U. S.
Geol. Surv., Bull. 550, 148, 1914.
7. Spurr, U. S.
(Republic, Wash.)
1. Eilers,
etc.,
Inst.
in blister copper.)
Geol.
Surv., Prof. Pap., 42:

92, 1905.
(Se in
Truscott, Inst. Min. and Met., Trans., X: 54, 1901.
Sumatra.)
Tonopah
ores.)
8.
(Redjang Lebong,
ECONOMIC GEOLOGY
810
TANTALUM
This element has attracted some attention because of
its
use
in electric lamps.
Tantalite (FeTa 2 O 6 ) and columbite [(Fe, Mn)Nb 2 O 2 ] are the

only minerals found in the United States from which tantalum
could be produced.
said to be found in
of
They occur
in
some abundance
pegmatite veins, and are

in those of the Black Hills
Other occurrences are near Canyon City,

North Carolina; near Amelia,
South Dakota.
near Spruce Pine,
Colorado;
Virginia, etc.
The tantalum market
is
now
said to be supplied mainly
mangano-tantalates from western Australia

navia has also supplied some (l).
rich
(2).
by the
Scandi-
REFERENCES ON TANTALUM
1.
Baskerville, Eng. and Min. Jour.,

U. S. Geol. Surv., Min. Res., 1908.
1909.
380,
(S.
Dak.)
4.
Watson,
LXXXVI:
2. Hess,
1100, 1909.
Hess, U. S. Geol. Surv., Bull.
Min. Res. Va., 1907: 298, 390.
3.
(Va.)
TELLURIUM
This element has but slight commercial value, as little use has
been found for it. The somewhat widely distributed telluride
of gold and silver ores form a comparatively common source
of it, but owing to the lack of demand, no attempt is made to
save the tellurium. Cripple Creek, Colorado, is the best-known
occurrence in the United States, the tellurium minerals present
being sylvanite (AuAg)Te 2 and calaverite (AuTe 2 ). Tetra-
dymite (Bi 2 Te.s)
The
is
found at a number of
tellurium of
from copper
commerce
is
all
localities.
obtained as a by-product
ores. 1
been made to utilize

a reddish tint. An
alloy of aluminum, zinc and tellurium has been patented.
Uses.
Unsuccessful
attempts
tellurium in bearing metals.
have
It gives glass
TIN
Ore Minerals.
Cassiterite (SnO 2 ), with 78.6 per cent metallic

the
tin,
principal ore mineral of this metal, but owing to the
of
presence
impurities it rarely shows this composition.
is
Eilers,
Amer.
Inst.
Min. Engrs., Trans. XLVII: 217, 1914.
MINOR METALS
811
hardness (6-7), imperfect cleavage, non-magnetic character,

high specific gravity (6.8-7.1), and brittleness help to distinguish
it from other miner ails that are liable to occur with it.
Ilmenite
Its
and magnetite have sometimes been mistaken

Stream
Wood
tin is
for
it.
name
applied to cassiterite found in placers.

a variety of cassiterite having a fibrous structure.
tin is the
Stannite, or tin pyrites, a complex sulphide of copper, iron,

serves as an ore mineral.
and
tin, rarely
Mode
Occurrence.
of
lowing ways, not
As an
(1)
all
of
Cassiterite
them being
of
may
occur in
the
fol-
commercial importance
original constituent of igneous rock;
(2) as veins,
formed under pneumatolytic or hydrothermal conditions; (3) as

contact-metamorphic deposits; (4) as hot-spring deposits; and
(5) in placers.
Of these Nos. 2 and 5 are of commercial importance, the others

being rarely
so.
Cassiterite in Igneous Rocks (9)

Cassiterite is known to
occur as an original constituent of granite, but there are no
known magmatic segregations of economic importance. It may
.
also occur as a
primary constituent of pegmatite dikes, assoand phosphorus minerals, as near Gaffney,

South Carolina (10), or in the Black Hills, South Dakota (23).
These dikes exhibit sharp walls, and there is no replacement of
the wall rock by cassiterite.
Contact Metamorphic Deposits (9, 19).
This type is known
at a few localities.
Those of Pitkaranta, Finland, show cassiterite associated with scheelite, topaz and fluorite in limestone
near its contact with granite. 1
Another interesting deposit occurs on Lost River, Seward
Here the invasion of limestone by
Peninsula, Alaska (is).
granite has produced a contact zone, carrying pyroxene, tourciated with lithium
maline, axinite, pageite,, ludwigite, vesuvianite, fluorite, scapolite,
scheelite, cassiterite, magnetite, galena
known
and
sphalerite.
and Berggiessand
the
Zeehan
Tasmania
hubel, Saxony,
(19).
district,
Tin Veins. (9).
Tin veins or lodes, carrying usually casOther
cases
are
at Schwarzenberg
as the chief ore mineral of this metal, may evidently

be formed under different physical conditions.
The commonest type is that of pneuPneumatolytic Veins.
siterite
matolytic origin found usually in granite, or close proximity

1
Vogt, Krusch and Beyschlag, Ore Deposits, Translation,
405.
ECONOMIC GEOLOGY
812
rather uniform group of minerals (Fig. 286),

it, and showing a
the metallic ones including cassiterite, wolframite and scheelite,
bismuth, and others in lesser amounts, while
to
arsenopyrite,
the gangue minerals include quartz (important), lithia mica,

Cassiterite is the chief ore
etc.
topaz, tourmaline, fluorite,
Total occurrences
Quartz_
Fluorite
Tourmaline
Wolframite
Pyrite
Chalcopyrite
Muscovite
Arsenopyrite___
Orthoclase
Galena
Topaz
.Magnetite
Molybdenite
Sphalerite
Chlorite
Pyrrhotite
Scheelite
Stannite
Total fluorine mineralsTotal boron minerals
Total tung-sten minerals.
Approximate quantitative distribution of the more important minwith cassiterite. Length of line is proportional to the
number of occurrences. Height represents relative abundance.
very
= quantity unknown.
abundant; B= plentiful; C = prominent D = rare;
(After Ferguson and Bateman, Econ. Geol. VII.)
FIG. 286.
erals
associated
A=
is generally low, often under one

frequently occurs in the wall rock
on either side of the fissures, and where these are abundant a
mineral, but the tin content
per cent.
The
cassiterite
considerable mass of rock
be impregnated with ore.

is the metasomatic alteration of the wall rock, resulting in a coarse-grained mixture of
quartz, muscovite, lithia mica, topaz and tourmaline, called
may
characteristic feature of tin veins
greisen.
If tin is
present in the vein,
it
usually occurs in the
MINOR METALS
813
The tourmaline and topaz are

greisen, replacing the feldspar.
not always equally prominent, and one or the other may be absent.
Greisenization is not confined to granites, but may also be
developed in shale, slate, limestone and diabase.
The two following analyses, represent,
and II, greisen derived from it.
I,
the fresh granite,
ECONOMIC GEOLOGY
814
Tin appears to be formed in some

Hot Spring Deposits.
normal
at
cases by precipitation
pressure from thermal waters,
has been deposited by a hot
sinter
siliceous
for a stanniferous
spring in Malacca.
.2;
and EbO,
It
contains 8162, 91.8;
7.5 (quoted
Pneumatolitic.
Contact-
Hydro-
metamorphic.
thermal.
nd pressure
FIG. 287.
of the
(After
SnCb,
.5;
by Lindgren).
Hot Springs.
Diagram to illustrate the genetic distribution and gradation of some

more common minerals in their association with cassiterite only.
Ferguson and Bateman, Econ. Geol. VII.)
Placer Deposits (8, 9).

These form the most important
source of tin ore, and have been formed in the manner described
on p. 433. Accompanying the cassiterite there may be wolframite,
and other heavy minerals.
Distribution of Tin Ores in the United States (13). Tin has

been found at many localities in both the eastern and western
United States as well as in Alaska, but most of the deposits

have thus far proved to be of little or no commercial value.
North Carolina and South Carolina (10, ll).
In these two
states there is a belt of tin ore which extends from near Gaffney,
MINOR METALS
815
Cherokee County, South Carolina, across parts of Cleveland

and Gaston Counties, North Carolina, to near Lincolnton, being
in all 35 miles long.
The cassiterite is irregularly distributed
in pegmatite dikes in schists, the latter being metamorphosed
sediments interstratified with slates, marbles, and quartzites.
Gabbro, diabase, and granite intrusions are also present. This

proved to be of commercial value although
some mining has been done in years past, and a little ore shipped.
belt has not yet
.10
PIG. 288.
Sketch
map
showing location of Carolina tin belt.

U. S. Geol. Surv., Bull. 260.)
South Dakota and
known occurrence
Miles 35
Wyoming
(14,
of tin ores in the
'
(After Graton,
The most widely
23).
United States
is
in the
Black
Hills.
Tin was discovered in the Harney Peak district and later
The tin ore (cassiterite) occurs as disseminations
in Nigger Hill.
in pegmatites, in quartz veins,
and
in placers.
The occurrences
have never amounted to much.
Tin is found in the York region of the

Alaska (7, 15).
Seward Peninsula, where it occurs chiefly in placers and lodes
and at a number of other places, but as yet there has been little
The lode deposits show the following types:
production.
(1) quartz veins cutting phyllites or metamorphic slates;
disseminations in more or less altered granite rocks; (3)
quartz porphyry dikes cutting limestone,

fluorite, zinnwaldite, etc.
(2)
in
and accompanied by
ECONOMIC GEOLOGY
816
Cassiterite veins are known in many parts of the

Foreign Deposits.
world (8). The Cornwall, Eng., deposits, worked for many years, show tin
veins occurring in post-Carboniferous granites, and also in slates (killas)

intruded by them. An interesting feature is the presence of copper with
little tin in the upper parts of the veins, which changes to a straight tin ore
where the veins pass from slate to granite. Not a little tungsten is alsc
obtained from some of the workings.
Another classic district is that of the Erzgebirge l in Saxony, and neighboring parts of Bohemia. At Altenberg (Fig. 289), the ores form a stockwork of small veins cutting a post-Carboniferous granite (Plate XLI, Fig. 2,
and Plate LXXV, Fig. 1) and an
older granite porphyry, the devel
opment of greisen being quite ex-
In the neighboring Zinn-
tensive.
wald deposits, the flat veins appear

to be formed largely by filling.
Interesting and important deposits are those of
Mount Bishoff
Tasmania, where the schists have

been cut by dikes of granite
porphyry, both rocks being replaced
and the
by tourmaline and topaz,

entire mass carrying veins
of cassiterite. 2
Curious because of their mineralogical relations are the Boliv-
ian veins. 3
which
is
The country
Devonian
slate,
rock,
intruded
by granite porphyry dikes, is exAssocitensively tourmalinized.

ated with the cassiterite is stanstephanite,
nite,
tetrahedrite,
ruby
silver,
blend o wolframite,
arsenopyrite, etc.
The Mexican ores are unique

because of their occurrence in
rhyolite, but of little commercial
FIG. 289.
map
of AltenbergSaxony. 1. Por2. Teplitz

phyritic granite;
quartz
porphyry; 3. Granite with flat tin
Zinnwald
Geologic
tin district,
lodes; 4. Silicified
porphyry; 5. Quartz
porphyry impregnated with tin ore;
6.
7. Tin
Steep tin lodes;
gravel.
(After Vogt, Krusch, und Beyschlag, I.)
1
2
3
value.
The
chief source of the world's

is the Malay PeninBanka and Billiton
The ore
off Sumatra.
production
sula,
and
Islands
here
is
obtained
chiefly
4
placers. Tin veins are also
in both districts.
Singewald, Econ. Geol. V: 166 and 265, 1910.

Krusch, Zeitschr. prak. Geol., 1900: 86.
Rumbold, Econ. Geol., IV: 321, 1909.
Penrose, Jour. Geol. II: 135, 1903.
from
known
PLATE
1-
Old workings of
FIG. 2.
tin
LXXV
mine, Altenberg, Saxony.
Rutile mine, near Roseland, Va.
(H. Ries, photo.)
(H. Ries, photo.)

(817)
ECONOMIC GEOLOGY
818
Tin is used chiefly for the manufacture of

bronze and tin plate, and to a smaller extent in plumbing as well
Britannia metal is composed of
as less important purposes.
tin
of
90
to
from 82
alloyed with antimony, copper, and
parts
Uses
of Tin.
sometimes zinc.
The amount of tin produced in the
Production of Tin.
United States including Alaska is entirely too small to supply
the demand, and the main source of supply for this country,
and indeed
of
regions
for the world,
is
the
Malay
peninsula, while other
commercial importance are Australia and Bolivia.
The available figures are

The tin ore produced
given below.
in
Alaska in 1914 amounted to 157.5
tons of concentrates, carrying 104 tons of tin, worth $66,560.

The only tin produced in the United States came from near
S.
Tinton,
The
tin
Dak.
imported into the United States in 1914 amounted
to 52,919 short tons, valued at $32,943,059.
WORLD'S PRODUCTION OF TIN IN

London
1914, IN
SHORT TONS
deliveries
23,335
Continent of Europe
Cornwall (production)
22,747
6,720
21,000
Bolivia (shipments)
South Africa (shipments)
5,600
China (shipments)
United States (receipts)
2,128
48,505
Total
Deductions of
130,035
Straits, etc.,
Bolivia, etc., Arriving in
from continent and English,

United States
Total
9,635
120,400
REFERENCES ON TIN
1.
Blake, Amer.
Min. Engrs., Trans. XIII: 691. (Black Hills.)

2. Blake, U. S. Geol. Surv., Min. Res. 1883-1884: 592, 1885.
(Ores
and deposits.) 3. Brock, Min. Soc. Nova Scotia, Jour. XVII:
4. Chapin, U. S. Geol. Surv., Bull. 592: 385 and 397,
50.
(N. B.)
1914.
(Seward Penin.) 5. Collier, U. S. Geol. Surv., Bull. 225, 1904.
(Alaska and general.) 6. Collier, U. S. Geol. Surv., Bull. 340: 295.
1908.
(Wash.) 7. Fay, Amer. Inst. Min. Engrs., Bull. Sept., 1907,
T
(Cape Prince of Wales, Alas.) 8. Fawns, Tin Deposits of the W orld,
London, 1905. 9. Ferguson and Bateman, Econ. Geol. VII: 209,
Inst.
10. Graton, U. S. Geol. Surv., Bull. 293,

11. Graton, U. S. Geol. Surv., Bull. 260:
Appalachians.)
12. Hess, Smithson, Misc. Collections,
(X. Ca. and S. Ca.)
1912.
(Geologic features.)
1906.
(S.
188, 1905.
MINOR METALS
819
13. Hess and Graton, U. S.

(Bibliography.)
260:
(Occurrence and distribution.)
161, 1905.
14. Hess, U. S. Geol. Surv., Bull. 380:
15.
(S. Dak.)
134, 1909.
Knopf, U. S. Geol. Surv., Bull. 358, 1908. (Alas.) 16. Miller, Can.
LVIII, No.
2,
1912.
Geol.
Surv.,
Bull.
Min.
Jour.,
XXXII:
582,
1911.
and Trans., XII,
(Ont.)
17. Piers,
Nova
Scotia
18. Rich(N. S.)

239, 1912.
(Franklin Mia., Tex.)
ardson, U. S. Geol. Surv., Bull. 285: 146, 1906.
19. Singewald, Econ. Geol., VII: 263, 1912.
(Genetic relationships.)
Inst. Sci., Proc.
Pt. 3:
Umpleby, U. S. Geol. Surv., Bull. 528, 1913. (Lemhi Co., Ido.)

Watson, Min. Res. Va., 1907: 567. (Va.) 22. Weed, U. S. Geol.
23. Ziegler, Min. and Sci. Pr., CVIII,
Surv., Bull. 213: 99, 1903.
Nos. 15 and 16, 1914. (Harney Peak, S. Dak., pegmatites.)
20.
21.
TITANIUM
While more than sixty mineral species contain titanium, the largest concentrations of the element occur
Ore Minerals.
as rutile (Ti02, 60 per cent Ti

ferous magnetite (see p. 520).
when
pure), ilmenite, or titaniRutile is at present the chief
source of the element, but even the workable deposits of this

are few, widely separated, and insufficient to supply the world's
demand, so that
it
has been necessary for some uses to turn to
ilmenite or highly titaniferous magnetites.

Rutile is formed as a constituent
Mode of Occurrence (4)
.
of:
(1) igneous rocks:
morphic deposits;
rocks.
Of these,
pegmatite dikes:
(2)
(4) veins;
1
and
2,
and
(5) regionally
rarely 3
and
5,
contact-meta-
(3)
metamorphosed
serve as important
sources of rutile.
While rutile may occur in both volcanic and plutonic igneous

rocks, most of the known commercially important deposits
are associated with gabbro (including anorthosite), and usually
formed by magmatic differentiation. The region of Amherst
and Nelson counties in Virginia, Bay St. Paul, Quebec, Canada,
and Kragero area in southern Norway, are of this type. A
second important type found in Virginia, occurs as dike-like
bodies of the ultrabasic igneous rock nelsonite (4).
Rutile and ilmenite have been found in apatite veins in
and Sweden, and

It
may
in pegmatite dikes in Virginia (4)

also be found in placer deposits, as it
weathering.
Distribution of Rutile in the United States
found
in
Alabama,
the
eastern
United States from
Norway
and Texas
(4).
is
resistant to
(4).
Although
England to
New
only the Virginia deposits are of commercial value
ECONOMIC GEOLOGY
820
and
have
supplied
the
entire
domestic
since
production
1902.
Here there are two areas, viz., the Amherst-Nelson County

(Fig. 290), one on the northwest edge of the Piedmont Plateau,
and the Goochland and Hanover counties area, near the
central-eastern margin of the
same province.
In the Nelson county area
all igneous, de-
the rocks are

rived from a
magma, and
common
parent
characterized
by
the prominence of apatite,
il-
menite,rutile,and more rarely

titaniferous magnetite.
rock types present are:

Biotite
gneiss
FIG. 290.
Map
showing location and

Nelson
(After Watson, Min.
relations of rutile deposits in
County, Va.
quartz
and
schists,
The
(1)
monzonite
which form
the country rock; (2) syenite, the most important rock
type of
the
rutile
district,
consisting chiefly of andesine

feldspar and a little blue
Res. Va., 1907.)
quartz, a hornblendic (secondary from pyroxene) facies containing

abundant blue quartz and andesine feldspar, and near its margin,
amounts of ilmenite and apatite; (3) gabbro;

a
rock
(4) nelsonite,
occurring usually along the border portion
of the syenite, and composed chiefly of apatite, with ilmenite
or rutile, or both in varying proportions; (5) gabbro-nelsonite
intermediate between 3 and 4; 6, diabase dikes.
rutile,
and
lesser
The rutile occurs as grains and segregations in the syenite,

or as a constituent of the dike-like nelsonite bodies.
In the
former
it varies in quantity from sparsely disseminated grains,

to
30
up
per cent of the mass, but in the quarries near Roseland
(Plate LXXV, Fig. 2) averages 4 or 5 per cent.
The rock
is
milled
and both the
rutile
and ilmenite saved.
Nelsonite rutile was also mined (Fig. 291) formerly.

In the Goochland-Hanover counties area the rutile occurs in
pegmatite.
Canada
is
(3)
The
chief
near St. Urbain, north of
known occurrence of Canadian rutile

Bay St. Paul, Quebec. The ilmenite-
MINOR METALS
rutile deposits occur in anorthosite.
The
821
larger ilmenite bodies
form elongated masses, with usually sharp boundaries, and most

of them are free from rutile.
A second, and more important
type is a rutile and sapphirinebearing ilmenite. Both types
are magmatic differentiation
products.
considerable
quantity of
ore
was shipped
in 1910.
Other Foreign Deposits
At Kragero, Norway, 1
(4).
rutile occurs
in a large aplite dike, either as dis-
seminated grains, or more important

as schlieren, representing local en-
In South
richments of the mineral.

Australia, (4)
rutile
known
is
to
occur near Mount Crawford, about

25 miles northeast of Adelaide, the
enclosing rock
being presumably
pegmatite.
Titanium is used
producing yellow under-
Uses.
for
glaze colors
also in the
artificial
on pottery, and
manufacture of
teeth, to give
SECTION ON LINE A-B
""
them
*>
**
Plans and vertical section in

an ivory tint. Another USe is FlQ 29 1.
-,
General Electric Company's mine, Neln
in the alloy ferro-titanmm.
son CountV) Va
(After Watson and Ta _
Its commercial values as a
ber, Va., Geol. Sun., Bull. III-A.)
-
,.
steel-hardening metal are not
yet thoroughly proven, but from .5 to 3 per cent titanium appears

to material!}'' increase the transverse and tensile strength of steel.
the use of the electric furnace, ferro-titanium can be produced directly from the ores, which would open a use for our
American titaniferous magnetites. Rutile is used in electrodes
By
for arc lamps.
The domestic production in 1914 came from

Nelson
County, Va., and amounted to 94 tons of rutile,
Roseland,
cent
95
TiO2 and, as a by-product, 89 tons of
carrying
per
about
55 per cent of Ti(>2. Concentrated
ilmenite, carrying
Production.
Watson, Amer. Jour.
Engrs.,
XXX:
646, 1901.
Sci.,
XXXIV:
509,
1912;
Vogt, Amer. Inst. Min.
ECONOMIC GEOLOGY
822
$50 to $400 per ton, depending on purity, fineness

and quantity purchased.
rutile sells for
of crushing,
ANALYSES OF RTTTILE
MINOR METALS
minerals that
Among the
are
galena,
may
siderite,
pyrite,
823
be found accompanying tungsten
quartz,
chalcopyrite,
pyrrhotite,
fluorite, tetrahedrite, sphalerite, barite, cassiterite, topaz, arsen-
opyrite, etc.
The tungsten minerals may occur in the deposits

some veins in bands.
as dissemina-
tions, pockets or masses, or in
Tungsten minerals are

United States,
and yet but very few of these are normally of commercial importance, the quantity available usually exceeding the demand.
The abnormal conditions produced by the European war, and
consequent enormously high prices, have stimulated the development of tungsten deposits in the United States.
A few of the occurrences are referred to below, partly to give
known
number
to occur at a
some idea
mode of occurrence.
The most important timgtsen
of the
Colorado
of localities in the
(10).
deposits
of
found in southeastern Boulder County. The

which
is pre-Cambrian granite and gneiss, has
country rock,
been subjected to fissuring accompanied by crushing and brecciation, and in the open spaces thus formed the ore mineral
ferberite has been deposited.
The metalliferous solutions also
Colorado
carried
are
much
and the following important periods
silica,
have
of
been
distinguished, each separated by

movement
and
brecciation
secondary
along the veins: 1, silicification and partial cementation of breccia with slight depo-
mineralization
sition of tungsten;
2,
deposition of tungsten;
3,
precipitation
by second important deposition of tungsten.

There is also a strong suggestion of solution and secondary
enrichment. The friable character of the ferberite and the
highly siliceous nature of some of the ores cause some difficulty
of silica followed
in concentration.
These deposits form an important domestic source of tungsten at the present time.
Arizona (3, 16, 22)
Hiibnerite is found irregularly distrib.
uted in vertical quartz veins cutting granites and gneissic rocks,

near Dragoon, Cochise County.
California
(l).
In the Atolia district
of
San Bernardino
the second important domestic source, the ore

mineral scheelite occurs in veins with quartz and calcite in
County
(24),
grano-diorite
Nevada
and
(26).
schist.
The
veins occupy a shear zone.
Veins of hiibnerite are found in a granite por-
ECOXOMIC GEOLOGY
824
phyry in the Tungsten mining district southeast of Ely. The

gangue is quartz with a little fluorite, pyrite, and scheelite.
Wolframite is found near Lead City as
South Dakota (14).
horizontal, but irregular masses, associated with the oxidized,
These ores are replacements of a
refractory siliceous gold ores.
flat,
dolomite deposited by uprising thermal solutions.
Canada (7, 15, 25).

Tungsten ores have been reported
from a number of localities in Canada, but the production is
small and irregular, and comes from the scheelite-quartz veins
Other occurrences have been recorded from
of Nova Scotia.
Beauce County, Quebec, and the Slocan district of British Columbia
(15, 25).
Burma and the Shan States form the most

important source of the world's supply, the wolframite being obtained
from placers, derived from lodes, where it is associated with cassiterite and
quartz.
and
Queensland
greisen and placers.
l
In Portugal,
New
South Wales
have wolframite
the third largest producer,
wolframite,
in quartz veins,
associated with
and tungstite (\VO 3 ), as well as cassiterite, pyrite, arsenopyrite,

tourmaline and fluorite, is found in veins and stockworks.
scheelite
Uses of Tungsten.
Most of the tungsten produced is used in
the manufacture of tool steel, and the industry therefore depends
to a large extent on the condition of the steel industry.
Tungsten forms a
aluminum,
number
of alloys with other metals such as iron,
nickel, copper, titanium, tin, etc.
to a considerable extent for incandescent
tungsten
lamp
It is also
used in the manufacture of tungsten
is
employed
filaments.
steel,
Ferro-
and the
fluorescent properties of tungstate of lime make it useful in the

Rontgen ray apparatus. Tungsten is also employed for color-
ing glass, sodium tungstate is used in fireproofing curtains and

draperies, while other tungsten salts are used for weighting
silks.
Production.
The United
States production in 1914
amounted
to 990 short tons of concentrates carrying 60 per cent

valued at $435,000, which was 547 tons less than 1913.
the
first
time the Atolia,
Calif.,
district
WOs,
For
exceeded the Boulder
County, Colo., one.
The
world's
1
production for
1912,
the last year for which
Cameron, Queensland Geol. Surv., Kept. 188, 1904.

Came, N. S. W. Geol. Surv., Min. Res. No. 15, 1912.
MINOR METALS
825
practically complete statistics are available,

tons of concentrates carrying 60 per cent
was 9654 short
REFERENCES ON TUNGSTEN
1.
Aubury,
Ming. Bur., Bull. 38: 372. (Calif.) 2. Auerbach,
Eng. and Min. Jour., LXXXVI, 1908. (Cceur d'Alene, Ido.) 3.
4. Baskerville, Eng.
(Ariz.)
Blake, Min. Indus., VII: 720, 1899.
and Min. Jour., LXXXVII: 203, 1909. 5. Cooper, Eng. and Min.
(San Juan Co., Col.) 6. De Wolf, Eng. and
Jour., LXVII: 499.
Min. Jour., Apr. 15, 1916. (Ariz.) 7. Faribault, Can. Geol. Surv.,
Sum. Rep., 1909: 228. (N. S.) 8. Fitch and Loughlin, Econ. Geol.,
9. Fleck, Min. and Sci. Pr., CXII:
(Leadville, Colo.)
Jan., 1916.
Calif. State
134, 1916.
(Prep'n of tungsten metals.)
1st Kept., 1908.
U.
(Col., general,
12. Hills,
Can. Min.
Inst.,
Min. Soc. N.
XV:
George, Col. Geol. Surv.,

11.
Hess and
Schaller,
(Colorado ferberite and wolframite
series.)
10.
and bibliography.)
S.,
477, 1913.
XVII:
Jour.,
(Nova
55,
13.
Scotia.)
1912-13;
also
Hobbs, U.
S.
1902.
14. Irving,
13,
(Conn.)
Surv., 22d Ann. Kept., II:
U. S. Geol. Surv., Prof. Pap. XXVI: 158. (S. Dak.) 15. Johnston
and Willmott, Can. Geol. Surv., 1904. (Canada.) 16. Joseph, Eng.
Geol.
409.
(Wash.) 17. Kellogg, Econ. Geol.,
Jour., LXXXI:
1906.
18. Lindgren, Econ. Geol., II:
(Ariz.)
111, 1907.
19. McDonald, Min. and Sci. Pr., CXII: 40, 1916.
(Scheelite
and Min.
I:
654,
(Col.)
mining and grading.)
Ransome, U. S. Geol. Surv., Bull. 182: 86,

Ransome, U. S. Geol. Surv., Prof. Pap.
62: 103, 1908.
(Co3ur d'Alene, Ido.) 22. Rickard, Eng. and Min.
23. Rowe, Min. Wld., XXIX:
(Ariz.)
Jour., LXXVIII: 263, 1904.
778.
24. Runner, Min. and Sci. Pr., CXII:
(Idaho.)
405, 1916.
(Geology of tungsten.) 25. Walker, Can. Min. Inst., XI: 367, 1908.
26. Weeks, U. S. Geol. Surv., 21st Ann. Rept., VI: 319, also
(Can.)
263.
ibid., Bull. 340:
(Nev.) 27. Winchell, Econ. Geol., V: 158,
256.
(Silverton,
1910.
(Certain
Min. Res.
20.
Col.)
21.
minerals.)
tungsten
(General,
and U.
U.
28. Hess,
S.
Geol.
Surv.,
S. occurrences.)
URANIUM AND VANADIUM

Ore Minerals.
The minerals which carry one
or both of these elements,
and which are
of
or the other,
commercial im-
portance are: carnotite (K20-2U03- V2Os+8H20); roscoelite

or vanadium mica (HsK(MgFe)(AlV)4(Si03)i2); pitchblende or
uraninite
uvanite
(2UO3-3V2O5-15H20); descloisite
and vanadinite (Pb 5 Cl(PO 4 )3).
(V
(ZnPb(OH)V0
Of these carnotite is the most important ore in the United
States, not only because of its uranium content, which is in
more demand than the vanadium, but also because it carries
(UsOg);
4 ); patronite
radium, so
much sought
2 S 5)
after
now because
of its radio-active
ECONOMIC GEOLOGY
826
Associated
properties.
with
the
carnotite
is
more
or
less
roscoelite.
Uranium and Vanadium in the United States

uranium and vanadium in the
United States is a somewhat extensive area in western Colorado
The ore minerals occur
and adjoining portions of Utah (6, 8).
in the lower member of the La Plata (Jurassic) sandstone, being
Distribution of
(2,
The
12).
found either
chief source of
in the
disseminated form, or in joint fractures of
the rock.
seam which indicates an apparent

unconformity, and vary in thickness from 1 or 2 inches to over
30 feet. Much of the ore is low grade, and sorting is necessary
The
deposits
follow
to give a shipping product averaging 2 per cent UsOg.

it
may
run
much
portion of the ore
Locally
The vanadium content in a large procent

V20.5, but some of it runs considerper
higher.
is 1
ably higher.
The origin of these deposits has been a puzzling problem.

Vanadium is known to occur in small quantities in many sedimentary
trations
and the present deposits may represent concensurface waters, although Hess suggests that the dikes
rocks,
by
found in
this region
may have some
connection with the min-
eralization of the sandstone.
Deposits of carnotite in sandstone are also being worked near

(f), and the year 191-4 saw the first com-
Green River, Utah
mercial production of this mineral from the Henry Mountains,

L'tah, while near Temple, Utah, there was begun the production
a radium-bearing mineral new to science.
At Cutter, Sierra County, X. Mex. (7), vanadinite associated
with lead, zinc and copper, has been found in veins cutting
of uvanite, 1
Carboniferous limestone.
Pitchblende
has been found at a number of
localities in
the
most important deposits are those found

near Central City, Gilpin County, Colo.
The mines were
originally worked for gold (12, 14).
L'nited States, but the
The important European deposits of pitchblende

Foreign Deposits.
are found at Joachimsthal,- Austria, and at Johanngeorgenstadt, MarienThe veins are referred to under
berg, Freiberg and Schneeberg, in Saxony.
and cobalt.
Of great importance are the vanadium deposits at Minassagra, 20 miles
nickel
Hess and Schaller, Wash. Acad. Sci., Jour., IV: 576, 1914.
Becke, Zcitschr. prak. Gool., 1905: 148.
MINOR METALS
827
from Cerro de Pasco, Peru. 1 The ore mineral, patronite (V2 SJ is found as
a lens-shape mass in red shales, associated with a black hydrocarbon called
;
quisquerite.
The United
Production.
States
in
1914
produced 4294
short tons of dry ore, carrying 87.2 tons of uranium oxide, and
The ore was valued at $441,300,
22.3 grams of metallic radium.
and the production
is
Little is paid for the
the largest yet made.

it being the uranium and radium
vanadium,
that are chiefly desired.

Unfortunately most of the ore has been
shipped abroad in the past, but several companies have been
started in the United States for producing radium salts.
Uses
the oxide
glazes
Uranium.
of
is
and
used to
Uranium minerals are radio-active, and

some extent as a coloring agent in pottery
iridescent glass.
Certain salts have a limited use in
chemistry and medicine.

Uranium can be alloyed with
steel, but alloys of other metals

are
similar
having
properties
cheaper to produce.
The main use of vanadium is as an
Uses of Vanadium.
where great toughness and torsional strength are

sometimes used in certain tungsten alloys for
making high-speed tool steel. Metavanadic acid has been used
as a substitute for bronze paint, and vanadium chloride is used
as a mordant in printing fabrics, and the trioxide as a mordant
alloy in steels
needed.
It
is
in dyeing.
REFERENCES ON URANIUM AND VANADIUM

1.
and Min. Jour., LXXXVII: 257, 518, 1909. (Gen(General.)

Clarke, U. S. Geol. Surv., Bull. 616: 705, 1916.
4. Gale,
3. Fleck, Col. Sch. of M. Quart., Ill, No. 3, 1908.
(Col.)
U. S. Geol. Surv., Bull. 340: 257, 1908. (Routt Co., Col.) 5. Gale,
U. S. Geol. Surv., Bull. 315: 110, 1907. (Col.) 6. Hess, U. S. Geol.
Baskerville, Eng.
eral.)
2.
7. Hess, Ibid.:
(Placerville, Colo.)
157,
Surv., Bull. 530: 142, 1913.
1913. (N. Mex.) 8. Hess, Ibid.-.'lQl, 1913. (Grand River, Utah.) 9. Hillebrand and Ransome, Amer. Jour. Sci., 4th ser., X: 120, 1900.
(Col.)
10. Hillebrand,
Moore and
Amer. Jour.
Sci.,
XXIV:
141, 1907.
Kithil, Bur. Mines, Bull. 70, 1914.
12. Parsons and others, Bur. Mines, Bull.

radium, uranium and vanadium from carnotite.
Soc., Proc.
and
V:
Sci. Pr.,
11.
general.)
(Extraction
13. Pearce, Col. Sci.
14. Rickard, F., Min.

156, 1895.
(Uraninite, Colo.)
15.
851, 1913.
(Pitchblende, Gilpin Co., Colo.)
Jour. Sci., XXXIII: 574, 1912; and U. S. Geol. Surv.,
147, 1914.
Eng., Trans.
and
CM:
Wherry, Amer.
Bull. 580:
(Patronite.)
(U. S.
104, 1915.
XXXVIII:
iHewett, Amer.
16. Smith, Amer. Inst.

(Carnotite, Pa.)
(Present sources and uses.)
698, 1907.
Inst.
Min. Engrs., Trans. XL: 274, 1910.
Min.
INDEX
Allochthonous
coal, 10, 12.
Almaden, Spain, 775.

Abrasives,
artificial, 296.
Almandite, 290, 383.
buhrstones, 284.
Almeria, Spain, 291.

Altenberg, Saxony, 469, 816.
Aluminum, ore minerals, 750.
corundum, 292.
diamonds, 295.
diatomaceous earth, 290.
production, 756.
distribution, 286.
uses, 755.
emery, 292.
See Bauxite.
feldspar, 290.
garnet, 290.
grindstones, 286.
millstones, 284.
novaculite, 287.
oilstones, 287.
pebbles, 295.
pulpstones, 287.
pumice, 288.
production, 296.
quartz, 290.
references on, 296.
tripoli, 290.
volcanic ash, 289.
whetstones, 287.
Actinolite, 298.
Adams, F. D., 283, 437.
Adams, G. I., 134, 135, 136. 208, 259, 400,
655.
Adiassevich, A., 113.
Adobe, 176.
Alundum,
296, 756.
Alunite, for potash, 242.
Goldfield, Nev., 712.
Alunitization, 487.
Amatrice, 388.
Amber ore sand, 96.
Amelia, Va., 810.
Analyses of, anthracite, 9.
asbestos minerals, 298.
bauxite, 751, 754.
barite, 315.
bitumens, 122.
bituminous
coal, 9.
brines, 222.
brines, solid matter in, 226.
cadmium blende, 789.
calcium chloride brines, 230.

chromite, 790.
clays, 175.
Clinton iron ore, 543.

coal ash, 10.
elementary, 18.
U. S., 8.
copper ores, weathered, 478.
Africa, asbestos, 307; diamond, 295, 381;

gold, 737; mica, 368; phosphate, 280.
Aguilera, J. G., 730.
coal,
Akron, N. Y., 190.
corundum,
Alabama, bauxite,
diatomaceous earth, 319.
751;
clay, 179, 180;
coal, 35; granite, 146;
graphite, 349;
hematite, 542, limonite, 556; pyrite, 403.
244.
Alabaster,
Alabaster, Mich., 250, 253.
Alameda County,
Calif., 46.
Alaska, Auriferous lodes, 693;

791; coal, 46; copper, 588,
613; gold, 692, 734; gypsum,
troleum, 109; platinum, 806;
chromite,
602, 605,
253; petin, 811,
815.
Albany, N. Y., 335.

Alberta, cement, 202; coal, 50; natural
gas, 115;
phosphate, 278; salt, 225.
Albert County, N. B., 125.
Albertite, 118.
Albert Mines. N. B., 118.

Albite, 322.
Alexander, Ark., 338.

Algeria, antimony, 781; onyx, 154.
Algiers, 280.
Allen, E. T., 327, 564, 618, 655.
coals,
292.
feldspar, 323.
fluorspar, 333.
foundry sands, 335.

fuller's earth, 338.
gases, manufactured, 79.

glass sand, 341.
graphite, 344, 348.
greensand, 279.
greisen rock, 813.
gypsum, 253, 256.
hematite paint ore, 371.

hydraulic lime rocks, 189.
iron ores, Brazil, 548.
iron ores, Canada, 547.
iron ores, Lake Superior, 527,
528.
lake waters, 211.
limestones, 187.
limonites, 557.
lithographic stone, 354.
magnesite, 359.
829
INDEX
830
Analyses
of,
magnetite, 516.
magnetite, titaniferous, 521.
manganese, Ga., 764.

Mediterranean water, 213.
meerschaum, 363.
mineral waters, 424.
mine waters, 443.
monazite, 378.
natural cement rocks, 190.
natural coke, 5.
natural gas, 78.
natural rock cements, 191.
ocher::, 372, 374.
peat bog, layers in, 1.
petroleum, 71, 74.
phosphate rock, 272, 276.
cement materials,
Portland
192.
Portland cements, 193.

potash brines, 239.
pyrite, 403.
residual limonites, 554.
rock salt, 225.
rutile, 822.
sea water, 211.
semianthracite,
9.
semibituminous
coal, 9.
siderite for paint, 375.
tripoli, 413.
of,
vein bitumens, 120.

blende. Missouri, 644.
borax water, Clear Lake, 233.
coal gas, 79.
coal,
proximate,
6.
kaolin, 178.
maltha, 122.
oil shale, 120.
pozzuolan cement, 188.

producer gas, 79.
Searles Lake brine, 242.
sphagnum. 1.
sulphur, Utah, 397.
water gas, 79.

Anderson, R., 134, 321.
Andesite, for building, 149, 162.
for cement, 202.
Andrews, E. C., 794.
Anglesite, 622.
Anhydrite, difference from gypsum, 246.
distribution, 244.
mode of occurrence, 246.
origin, 247.
Annaberg, Sax., 787, 803

Annabergite, 795.
Anorthite, 322.
Anrep, A., 69.
Anthophyllite, 298, 300, 302.
Anthracite, analyses of, 9.
Canada,
779.
production, 782.
references on, 783.
sources, 780.
United States, 779.
uses, 781.
Apatite, as fertilizer, 260.
Apex, Colo., 573.
Apgar, F. W., 501.
Appalachian coal field, 28.
Apsdin, J., 191.
Apsheron Peninsula, Russia, 113.
Aquamarine, 383.
Arber, E. A. X., 65.

Arbuckle Mts., Okla., 147.
Argall, G. O., 634, 655.
Argall, P., 633, 655, 674, 771.
Argentite, 676.
Arizona, asbestos, 301; building stone, 149;

fluorspar, 330;
copper, 573, 600, 611;
garnet, 383; gypsum, 252; onyx, 154;
peridot, 384; potash, 242; tungsten, 823;
turquoise, 387.
asphalt, 120;
Arkansas, antimony, 780;
bauxite, 754; cement, 202; coal, 41; diamond, 381; granite, 147; limonite, 556;
manganese, 766; novaculite, 287; phosphate, 277; slate, 162; syenite, 148; zinc,
646.
talc, 409.
Analysis
Antimony, ore minerals,
50.
Pennsylvania, 29.
properties of,
Russia, 52.
5.
Wales, 52.
Anthraxolite, 80, 118.
Anticlinal theory of oil, 87.
Antimony, Canada, 780.

deposits, classification, 779.
foreign deposits, 781.
from blister copper, 780.
Arkose, 158.
Arnold, R., 66, 133, 134, 231, 321, 748.
Arsenic, foreign deposits, 784.
in smelter fumes, 783.
ore minerals, 783.
production, 785.
references, 786.
United States, 784.
uses of, 784.
Arsenopyrite, 783.
Artesian water, 417.
Asbestic, 307.
Asbestine, 307.
Asbestos, analyses, 298.
Canada, 302.
cross fiber, 298.
mass fiber, 299.
minerals, 298.
occurrence, 298.
origin, 305.
production, 308.
references, 308.
slip fiber, 299.
types, comparison of, 299.

United States, 300.
uses, 307.
Ashburner, C., 135.
Ashford, Wash., 9.
Ashley, G. H., 28, 37, 65, 66, 135, 184, 208,
353, 758.
Asia, coal, 52.
Aspen, Colo., 668.
Asphalt, lake, 121.
production, 131.
uses, 126.
vein, 121.
Asphaltite, 117.
Atacamite, 568.
Atlin, B. C., 356.
Attfield. 231.
INDEX
Aubrey, A. J., 756
Aubury, L.. 167, 321, 400, 618, 825.
Auerbach, H. 8., 825.
Australia, oil shale, 125; tantalum, 810.
Austria, barite, 316; bismuth, 787; coal
chromite, 792; cobalt, 803; graph350; iron, 548; magnesite, 356;
mercury, 775; zinc, 651.
52;
ite,
Autochthonous coal, 10.

Avery Island, La., 224.
Azurite, 568.
B
Babbitt metal, 781.
Babcock, E. J., 67, 185.
Bacteria, iron, 549.
sulphur, 394.
Bagg, R. M., 619.
Bailey, E. H. S.. 259.
Bailey, G. E., 228, 237, 620.
Bailey, L. W., 136.
Bain, H. F., 65, 66, 184, 329, 334, 414, 497,
619, 645, 656, 748.
Baker, M. B., 186.
Baker County, Ore., 698.
Bakersfield, Calif., 338.
Baku, Russia, 113.
Balakhany field, 113.
Ball, S. H., 209, 353, 370, 522, 537, 565, 566,
619, 620, 656.
Ballarat, Victoria, 705, 706.
Ball clay, 176.
Banat, Hungary, 518.
Bancroft, G. J., 500.
Bancroft, H., 486, 656, 657, 673, 745, 746,

748, 778, 809.
Bancroft, J. A., 406, 620.
Bancroft, W. D., 256.
Banff, Alberta, 50, 278.
Banka,
tin, 816.
Barbados, manjak, 121.

Barber, Kas., 252.
Barbour, E. H., 67, 297.
Barclay coal basin, 32.
Bard, D. C., 619.
Barite, analyses, 315.
associated minerals, 310.
Canada, 316.
deposits, form of, 309.
foreign, 316.
geologic age, 310.
mining, 316.
occurrence, 309.
origin, 316.
production, 317.
properties, 309.
references on, 318.
United States, 310.
uses, 316.
Barlow, A. E., 296, 799, 805.
Barnes, C., 747.
Barnett, V. H., 135.
Barr, J. A., 283.
Barrell, J., 451, 497.
Bartlesville, Okla., 102.
Bartling, R., 318.
Barton
Hill,
N. Y., 508.
Barus, C., 498.

Basalt, for building, 148.
831
Baskenovo, Russia, 307.

Baskerville, C., 136, 390, 794, 810, 822, 825,
827.
Bassler, R. S., 209.
Bastin, E. S., 68, 208, 327, 346, 353, 392,
'499, 619, 704, 745, 746.
Bateman, G. M., 812, 818.
Bateson, C. E. W., 746.
Batesville, Ark., 277.
Bathurst, N. B., 516, 547.
Baux, France, 750, 751, 755.
Bauxite, 750, 751.
analyses, 751.
impurities in, 751.
origin, 753, 754.
production, 756.
references, 758.
United States, 751.
uses, 755.
Bavaria, copper, 573; graphite, 350.
Bawdwin mines, Burma, 673.
Bayard sand,
97.
City, Mich., 38, 226.
W.
S., 421, 511, 564, 565.
Bayley,
Bay St. Paul, Que., 819, 820.
Bay
Bear Creek, Mont., 8.

Beauce County, Que., 824.
Beaume
scale, 72.
Beaumont, E. de, 440, 813.

Beaumont, Tex., 85, 106, 107.
Beaver Hill, Ore., 8.
Beaver sand. 96.
Beck, R., 470, 497, 500, 518, 659, 729, 826.
Becker, G. F., 80, 133, 217, 456, 501, 747,
772, 778.
Bedded
deposits, ores, 472.
Bedford, Ont., 323.
Bedford stone, 150.

Bedford Village, N. Y., 323.
Bedford, Virginia, 301.
Heeler, H. C., 748.
Beeson, J. J., 620.
Belgium, barite, 316; coal,

153; phosphate, 280.
Bell, J. M., 136, 567, 805.
52;
marble,
Bell metal, 614.

Bendigo, Victoria, 705, 706.
Bengal, mica, 368.
Berea grit, abrasive, 286.
Berea sand, oil, 96.
Berea sandstone, building, 158.
Berg, G., 497.

Bergeat, A., 497, 603, 609, 781.
Berggiesshiibel, Ger., 811
Berkeley, W. Va., 341.
Berlin, Wis., 336.
Bernice coal basin, Pa., 32.
Berthelot, M., 79.

Beryl, 383.
Bevier, G. M., 620.
Beyer, S. W., 168, 185, 208.

Beyschlag, F., 447, 497, 524, 548, 659, 672,
673, 705, 708, 729, 730, 775, 803, 811.
Bex, Switz, 247.
Big Cottonwood Canon, Utah, 668.

Big Injun sand, 96.
Big Stone Gap coalfield, 34.
Bilbao, Spain, 548, 559.
Billiton Islands, 816.
INDEX
832
Bingham, Utah, 580.
Binns, C. F., 184, 501, 646, 656.
Birkenbino, J., 527, 564.
Birmingham,
Ala., 35, 542.
Bisbee, Ariz., 573.

Bischof, G., 215, 395.
Bischof, K., 184.
Bishop, I. P., 208.
Bismitc, 786.
Book
Bismuth, foreign deposits, 787.

in smelter fumes, 786.
ore minerals, 786.

production, 787.
references on, 788.
United States, 786.
uses, 787.
Bismuthinite, 786.
Bismutite, 786.
Bitumens,
Utah,
603,
5.
Borneo, diamond, 295; petroleum, 113.

Bornite, 568.
Borocarbone, 296.
Borts, 295, 380.
solid, 117.
Bourry, E., 184.

Boutwell, J. A., 259, 585, 620, 674.
Bovard, Nev., 242.
Bowen, N. L., 229.
uintaite, 121.
vein, 117.
wurtzilite, 121.
Bituminous
coal, analyses,
properties
of, 2.
Bituminous rock, analyses, 124.

origin, 126.
production, 131.
properties, 124.
references on, 136.
ore, 559.
Mountain, Oklahoma, 120.
Black band
Black Fork
Black Hills, S. Dak., 148,180,811,815.
Black Lake, Que., 306.
Black lignite, 2.
Black sand, 731.
Blacksburg, Va., 9.
Blackwelder, E., 283.
Blagodat, Russia, 807.
Blake, W. P., 66, 136, 259, 730, 745, 758,
818, 825.
J. F.,
745.
Blatchley, R. S., 134.

Blatchley, W. S., 134, 185, 208, 390.
Bleiberg, Austria, 651.
Bleininger, A. V., 207, 208, 209.
Blende, 621.
Block coal, 32.

Blockton, Ala., 9.
Blossburg coal basin, 32.
Blount Mountain coal, 35.
Blow, A. A., 485, 634.
Blue billy, 559.
Blue ground, 382.
Blue Rapids, Kas., 252.
Bluestone, 158.
Bodenmais, Bav., 573.

lime, for cement, 191.
ore, 672.
Bohemia, silver-lead
Boise, C. W., 390.
Bosworth, T. O., 133.

Botetourt Co., Va., 754.
.
Boulder, Colo., 108.
Boulder County, Colo., 823.

Boulder, Mont., 442.
Boulder batholith, Mont., 593.
Boundary
Bow
8, 9.
609,
Boracite, 233.
Borates, hot spring waters, 233.
origin of, 235.
production, 236.
references on, 237.
United States, 233.
uses, 236.
Borax Lake, Calif., 211.
Borax. See Borates.
Bordeaux, A. F. J., 730.
anthraxolite, 118.
asphaltite, 117.
gilsonite, 121.
grahamite, 118.
lake asphalt, 121.
maltha, 122.
manjak, 121.
ozokerite, 118.
tabbyite, 121.
Bog
Cliffs,
copper,
albertite, 118.
solid, origin, 126.
Blandy,
Bolivia, bismuth, 787;

tin, 813, 816.
Bone coal, 31.
Bonine, C. A., 283.
Bonne Terre, Mo., 473.
district, Brit. Col., 590.
Island, Alberta, 115.
Bowling Green, Ky., 150.

Bownocker, J. A., 32, 67, 98, 134, 228, 230.
Boyle,
Jr.,
A. C., 618.
Bradford sand, 97.

Bradley, R. R., 406.
Brad, Transylvania, 729.
Braden Mines, Chile, 603.
Brandenburg, Ky., 354.
Branner, J. C., 136, 184, 208, 278, 283, 340,
639, 655, 758, 789.
Bransky, O. E., 340.

Branson, E. B., 216, 228.
Brass, 614, 651.
Braunite, 758.
Brazil, copper, 605; diamond, 295; gold,
548; manganese, 768; oil
695;
iron,
shale, 125; monazite, 378; topaz, 388.
Breece Hill, Leadville, 786.
Breger, C. L., 228.
Brewer, W. M., 745.
Brewster County, Tex., 774.
Bridges, J. H., 400.
Britannia metal, 781.
British Columbia, building stone, 162; cement, 202; clay, 181; coal, 50; copper,
gold-silver, 686;
590; diamonds, 382;
gypsum, 255; lead-silver, 659, 671; magnesite, 356; marble, 164; platinum, 807;
salt, 225; sandstone, 164; tungsten, 824.
Broadhead, G. C., 343.
Broadtop coal basin, 32.
Brochantite, 568.
Brock, R. W., 818.
Brocken Mountain, Germany, 672.
Brokaw, A. D., 745.
Broken Hill, N. S. W., 659.
Bromine, references on, 230.
sources, 229.
INDEX
Bromine,
uses, 229.
Bromyrite, 676.
Bronze, 614.
Brooks, A. H., 66, 133, 745, 793.
Brookville coal, 32.
Broughton, Que., 298.
Brown, C. S., 66.

Brown, R. G., 746.
Browne, D. H., 805.
Browne, R. E., 732, 746.
Brown
See Limonite.
ore.
Brownstone, 158.
Brummell, H. P. H., 353.
Brun, P., 441, 498.
833
Caddo field, La., 108.

Cadmium, occurrence,
788.
references on, 789.
uses, 788.
Cady, G. H., 748.
Cady, H.
P., 73.
Caen stone, 164.

Cahaba coal field,
35.
Cairnes, D. D., 68, 620, 748, 749, 779, 783.

Calabogie, Ont., 349.
Calamine, 621.
Calaverite, 675, 810.
Calcareous tufa, 150.

Calcasieu Parish, La., 396.
Bryan Heights, Tex., 396.

Buckingham, Que., 325, 349.
Calcium
Buckley, E. R., 167, 168, 186, 209, 316, 318,
bituminous rock,
California, basalt, 148;
124; borax, 233; cement, 202; chromite,
791; clay, 180; coal, 46; copper, 573, 593,
613; diatomaceous earth, 320; feldspar,
323; gold, 692, 695; granite, 148; gypsum, 252; magnesite, 356; maltha, 122;
manganese, 612, 766; marble, 153; mercury, 772; onyx, 154; petroleum, 102;
placers, 731; platinum, 806; potash, 241;
sodium sulphate,
salt, 224;
slate, 162;
646, 656.
Buckman, H.
O., 184.
Buehler, H. A., 168, 208, 478.

Buena Vista, Va., 557.
Buffalo, N. Y., 190.
Buhrstones, defined, 284.
sources, 284.
Building stone, anorthosite, 148.
Canada, 163.
basalt, 148.
chemical composition, 143.

diabase, 148.
foreign, 146, 153, 164.
gabbro, 148.
granite, 144.
life of, 143.
limestone, 149.
marbles, 152.
production, 165.
properties, 138.
quarry water, 142.
references on, 167.
rhyolite, 148.
sandstone, 157.
serpentine, 154.
slate, 160.
structure affecting quarrying, 144.
United
chloride, 230.
Calgary, Alberta, 111, 202.
231; talc, 410; tourmaline, 386;

sten, 823.
Calkins, F. C., 619, 674.
Callen, A. C., 377.
Calomel, 771.
Calumet conglomerate, 608.
Calvin, S., 343, 566, 656.
Cameron, F., 243.
Cameron, W. E., 794, 824.
Campbell, M. R.,
2, 15, 19,
Campbell's Run sand, 97.

Campbell, W., 805.
Camsell, C., 390, 452, 688, 749, 793, 808.
Canada. See individual provinces.
Cananea, Mex., 592.
Canaval, R., 362.

Caney Creek sand, 97.
Canmore, Alberta,
50.
Cannel, Tex., 43.
Butler, Tenn., 413.

Butte, Mont., 443, 470, 593, 767.
Buttram, F., 134, 297, 343.
Butts, C., 66, 566.
Byler, E. A., 747.
Carlsbad, Bohemia, 444.

Carlstadt, Alberta, 115.
Carmel, N. Y., 784.
Carnallite, 214.
Carne, J. E., 136, 824.
Carney, F., 343.
Carnotite, 825.
Carpenter, F. R., 748.
C
Cable Mine, Mont., 686.
Cactus Mine, Utah, 592, 692.
21, 65, 66, 133,
233, 237, 343.
States, 146, 152,

158, 160.
uses, 148, 154, 159.
Bullfrog, Nev., 729.
Burchard, E. F., 67, 168, 204, 207, 318, 334,
343, 377, 556, 566,
Burgess, J. A., 714, 747.
Burke, Ido., 660.
Burma, lead-silver ore, 673; tungsten, 824.
Burns, Kas., 253.
Burrell, G. A., 78.
Burro Mountains,
Mex., 483, 601.
Burrows, A. G., 748.
Burton, Ga., 409.
Butler, B. S., 243, 498, 617, 619, 620, 674.
Butler, G. M., 655.
Butler sand, 96.
New
tung-
Cannel
coal, properties of, 4.
Cannelsburg, Ky., 36.
Canon City, Colo., 42, 367.

Canyon City, Colo., 810.
Canton, N. Y., 403.
Cape Lisburne, Alas., 48.

Cape Nome, Alas., 735.
Cape Yakataga, Alas., 110.
Carbonado, 295, 380.
Carbonate ore, iron, 559.
Carbon black, 116.

Carbon County, Mont.,
Carbonite,
44.
5, 35.
Carbon Mountain, Alas.,

Carborundum, 296.
Carll, J. F., 134.
9.
INDEX
834
Carpenter, J. A., 297, 619.
Carrara, Italy, 164.
Carroll sand, 96.
Carter, T. L., 745.
Cartersville, Ga., 315, 372, 751, 764.
Carter, W. E. H., 68.
Caspian Sea, 211, 215.
Cassiterite, 810.
Castle, Mont., 767.
Castle Dome district, Ariz., 330.
Castle Rock, Colo., 148.
Catlett, C., 65, 209, 498.

Caucasus, Russia, 113.
Cauldwell, F. W., 768.
Cave Spring, Ga., 704.
Cavities, ore deposits, origin, 455.
Cayeux, L., 556.
Cazadero, Calif., 359.
Cebolla Creek, Colo., 520.
Celestite, 392.
Cement, hydraulic, 188.
hydraulic lime, 189.
natural rock, 190.
oxychloride, 300.
plaster, 250.
Portland, 191.
pozzuolan, 188.
production, 205.
references on, 207.
Roman,
190.
Rosendale, 190.
slag, 189.
uses
205.
Chromic
iron ore, foreign deposits, 792.

minerals, 789.
production, 792.
references on, 793.
United States, 791.
uses, 792.
value of ores, 489.
Chromite, 789.
Chrysocolla, 568.
Chrysotile, 298, 302.
Chuquicamata, Bolivia, 603.
Cinnabar, 771.
Cippolino marble, 164.
Cirkel, F., 306, 308, 353, 793.
Clapp, C. H., 68, 185, 202, 243, 620, 656.
Clapp, F. G., 88, 133, 135, 209, 421.
Clarion coal, 32.

Clark, J. D., 617.
Clark, W. B., 66, 208, 283.
Clarke, F. W., 65, 70, 133, 213, 228, 231,
237, 259, 282, 318, 390, 400, 435, 497, 498,
827.
Clarksburg, W. Va., 8.
Clarion County, Pa., 8.
Clausthal, Ger., 467, 672.
Clay, analyses, 175.
classification, 174.
definition, 170.
eolian, 172.
flint, 176.
floodplain, 171.
for cement, 191.
Central City, Colo., 702, 826.

glacial, 172.
Cerargyrite, 070.
geologic distribution, 176.
of,
Cerbat Range,
Ariz., 453.
Ceresin, 120.
Cerrillos coal
field, X. Mex., 16.

Cerillos Hills, X. Mex., 5.
Cerrillos, X. M., 42.
Cerro de Pasco, Peru, 827.
Cerro de Potosi, Bolivia, 813.
Cerussite, 622.
Ceylon, graphite, 349; mica, 369; topaz, 385.
Chaff ee County, Colo., 671.
Chaleanthite, 568.
Chalcoclte, 568.
Chalcopyrite, 508.
Chalk, definition, 150.
Chamberlin, R. T., 441, 498.
Chamberlin, T. C., 209, 421, 500, 049, 657.
Chapin, T., 818.
Chara, 202.
Charleston, S. C., 266.
Charpentier, T. F. W., 465.
Charter Towers, Queensland, 706.
Chatsworth, Ga., 407.
Chattanooga, Tenn., 35, 751.
Chauvenet, R., 564.
Cheshire, Mass., 341.
Chestnut Yard, Va., 612.
Chiapas, Mex., 686.
Chichagof Island, Alas., 253.
Chile, copper, 603; nitre, 232.
kinds
of,
170.
lake, 171.
marine, 171.
production, 183.
properties, 172.
references on, 184.
residual, 170.
shale, 171.
transported, 170.
United States, 178.
uses of, 182.
Clay ironstone, 558.
Clayton, la., 341.
Clear Lake, Calif., 233.
Clements, J. M., 505.
Clendenin, W. W., 185.
Cleveland, O., 220, 222.
Clifton, Ariz., 577.
Clinton ore, age, 537.
occurrence, 537.
origin, 545.
United States, 537.
Clinton sand, 97.
Cloverport sand, 96.
Coal, Alaska, 46.
anthracite, 5.
field, 28.
ash, analyses of, 10.
Appalachian
ash
in, 6.
China, antimony, 781; coal, 52.
associated rocks, 22.
China
Chorolque, Bolivia, 787.
bituminous,
blossom, 22.
bone, 3.
Chromic
Canada,
clay, 176.
Chloanthite, 795.
iron ore, analyses, 790.
Canada, 791.
2.
47.
cannel, 4. 36.
INDEX
Coal, classification, 18.
coke, natural, 5.
coking, 4.
delta deposits, 12.
Eastern Interior field, 35.
faults in, 24.
fixed carbon, 6.

fuel ratio, 6.
gas, analysis of, 79.

Gulf province
ingredients
kinds
lignites, 45.
of, 6.
of, 1.
lignite, 2.
moisture
in, 6.
Northern Interior
field,
37.
origin of, 10.

outcrops, 22.
Pacific coast field, 45.

peat, defined, 1.
Philippines, 52.
pinches, 23.
production, 52.
proximate analysis,
6.
references on, 65.

reserves of world, 52.
Rocky Mountain
semianthracite,
fields,
42.
4.
slate in, 23.

smut, 22.
Southwestern
835
Colgate, Okla., 102.

Colles, G. W., 370.
Collier, A. J., 19, 65, 66, 619, 818.
Colloids, in ores, 461.
Collophanite, 261.
Colombia, platinum, 807.
Colorado, artesian water, 418; bismuth,
786; building stone, 149; cement, 202;
clay, 180; coal, 42; copper, 573; feldspar,
323; fluorspar, 329; gilsonite, 122; gold148; gypsum, 252;
silver, 702; granite,
630, 636;
lead-zinc,
iron,
516, 520;
limonite, 552; manganese, 767; marble,
153; mica, 367; oil shale, 125; onyx, 154;
petroleum, 108; potash, 242; selenium,
809; silver-lead, 668, 671, 673; tungsten,
823; uranium, 826; vanadium, 826; volcanic ash, 290.
Coloradoite, 771.
Columbia, Pa., 341.
Columbite, 810.
Colville basin, Alas., 48.
Colvocoresses, G. M., 803.
Commentry, France, 12, 23.
Comstock Lode, Nev., 718.
Comstock, T. B., 783.
Condit, D. D., 134, 337.
Condra, G. C., 422.
Connate water, in ore formation, 438.
Conneaut, O., 335, 336.
179; dia322; sandstone,

tourmaline, 386; vein quartz, 391.
Contact metamorphic deposits, 448, 473.
Connecticut, beryl,
field, 38.
splits, 23.
structural features, 22.
subbituminous,
sulphur in, 10.
2.
base,
158;
148;
383;
clay,
feldspar,
copper, 573.
gold-silver, 686.
swelling, 23.
thickness of beds, 22.
Triassic field, 35.
iron, 513.
lead-zinc, 626.
origin, 449.
volatile matter, 0.
weathering of, 25.
Western Interior
Coaldale, Nev., 242.
Coal Harbor, Alas.,
Coal Hill, Ark., 9.
field, 38.
8.
Coalinga, Calif., 102.

Coalville, Utah, 8.
Cobalt, ore minerals, 794.

other foreign deposits, 803.
production, 804.
references on, 805.
United States, 794.
uses. 804.
Cobalt-arsenopyrite, 795.
Cobalt bloom, 795.

Cobaltite, 795.
Cobalt-tourmaline veins, 448.

Cockeysville, Md., 153.
Cody, Wyo., 397.
Cceur d'Alene, Ido., 660.
Coffeen, 111., 8.
Coke,
4.
natural, 5.
Cokeville, Wyo., 276.
Cole, A. A., 749.
Cole, L. H., 229, 259.
Coleman, Alberta, 50, 51.
Coleman, A. P., 136, 296, 567, 796, 798, 805.
Colemanite, 233.
Coleraine, Can., 790.
tin, 811.
Cook, C. W., 228, 230, 239.

Cook, G. H., 185, 283.
Cooke, H. C., 499, 620.
Cook
Inlet, Alas., 48, 109.
Cooper, A. S., 134.

Cooper, C. A., 825.
Coopers, W. Va., 9.
Cooper sand, 96.

Coosa coal field, 35.
Coos Bay coal field, Ore.,
46.
Copper, Alaska, 588, 602, 613.
antimony in, 780.

bismuth in, 786.
Canada, 590, 613.
contact metamorphic deposits, 573.
deposits by circulating water, 592.
deposits in schists, 610.
gangue minerals, 569.

hot spring deposits, 443.
impurities in ores, 569.
intermediate vein zone deposits,
593.
lower vein zone, 592.
magmatic segregations, 572.
meteoric water deposits, 609.
native, 568.
native, deposits of, 603.
nickel in, 796.
INDEX
S36
ore minerals, 568.

origin, 569.
Cumberland, Md., 191, 196.

Cumberland, X. S., coal, 47.
Cumenge, E., 745.
other foreign deposits, 614.

production, 615.
Cummings, U., 207.

Cummins, W. F., 228.
references on, 617.

reserves, 617.
Cuprite, 568.
Curie, J. H., 745.
Curtis, J. S., 674.
Cushman, A. S., 243, 327.
Cutters, in phosphate, 268.
Cutter, X. Mex., 826.
Cuyuna range, Minn., 532.
Copper, occurrence, 509.
secondary enrichment, 485.

superficial alteration, 570.
tellurium
in,
810.
United States, 572, 573, 592, 593,

610.
uses of, 614.
value of ores, 488.

weathering reactions, 480.
Copper Mountain, Alas., 588.

Copperopolis, Calif., 692.
Copperopolis, Ore., 593.
Copper Queen Mine, Bisbee, Ariz., 573.
Copper River, Alaska, 109.
Copper River district, Alaska, 602.
Coquina, definition of, 150.
Core sand, 334.
Cornish stone, 324.
Cornwall, Eng., 182, 324, 816.
Cornwall, Pa., 449, 512.
Corocoro, Bolivia, 609.
Corundum, analyses, 292.
Canada, 294.
occurrence, 292.
preparation, 294.
United States, 293.
Corundum Hill, X. C., 292.
Coste, E., SO, 133.
v. Cotta, B., 497.
Coulbeaux, M., 236.
Coulters station, Utah, 118.
Covellite, 568.
Covington, Va., 557.
Cow Run sand, 96.
Cox, C. F., 321.
Cox, E. T., 781.
Cox, G. H., 650, 656.
Coxville, Ind., 341.
Craig, E. H. C., 133.
Cranbrook, B. C., 659.
Crane, G. W., 564, 656, 666, 674.

Crane, W. R., 66, 134, 745.
Crawford, R. D., 746.
Creede, Colo., 636, 673.
Crenshaw,
J. I,.,
655.
Crested Butte, Colo., 9, 16, 42.

Crider, A. F., 185, 208, 422.
Crimora, Va., 755.
Cripple Creek, Colo., 719, 810.
D
Dachnowski,
A., 69.
Daggett, Calif., 233.

Dahllite, 261.
Dake, C. L., 566.
Dale, T. X., 167, 168.
Dalton, L. V., 113, 133.
Dammer,
125, 182, 255, 282, 316, 338,

355, 362, 368, 400, 412, 755.
Danville, Ky., 315.
Que., 306.
Darton, X. H., 168, 196, 228, 297, 334, 421.
Daubree, A., 813.
Davidson, W. B. M., 282.
B.,
Davis, C. A., 62, 64, 68, 69, 82.

Davis, X. B., 184.
Davis, coal, 32.
Mass, 403.
Day, A. L., 217, 327, 441, 456, 485, 498, 501.

Day, D. T., 73, 85, 91, 94, 113, 133, 135,
136, 340, 808, 809.
Sea, 211.
C., 591.
Calif., 233.
Deeatur County, Ga., 338.
De Golyer, E., 111.
De Kalb, C., 169.
Dead
Deadwood, B.
Death Valley,
De La
Beche, H., 461.
Delkeskamp, R., 500.

Deming, X. M., 329.
Denmark,
flint,
295.
Dennis, L. M., 379.

Derby, O. A., 390, 548.
Derbyshire, Eng., 332.
Descloisite, 825.
Detroit, Mich., 220.
Deussen, A., 422.

De Wolf, F. W., 100, 185.
DeWolf, W.
P., 825.
Dexter, Kas., 73.

Diabase, as building stone, 148.
Diamond, as abrasive, 295.
Critical level, defined, 457.

Crocidolite, 298.
bort, 380.
Canada, 382.
Crockett, Tex., 8.
Crooks, A. R., 794.
origin, 382.
Crosby, W.
O., 136, 185, 451, 497.

Cross, W., 673, 746.
Crows Nest Pass, Can., 50.

Crump, M. H., 136, 168.
Crustification, in veins, 466.
Cryolite, 332, 750.
Cuba, iron, 518, 558.
Cullinan diamond, 382.
Culm, 31.
Cumberland, Eng., 255, 548.

Cumberland Hill, R. I., 521.
carbonado, 380.
properties, 380.
South Africa, 381.
United States, 381.
Diaspore, 750.
Diatomaceous earth, analyses, 319.
occurrence, 318.
properties of, 318.
United States, 320.
uses, 320.
Dick, W. J., 283.
INDEX
Dickinson, H. T., 168.
Dickson, C. W., 316, 318, 799, 805.
Diller, J. S., 67, 297, 308, 412, 564, 746, 748,
793.
Dillon, Kas, 253.
Mont,, 349.
ores, copper, 600.

Dolbear, C. E., 243.
Dolbear, S. H., 771, 793.
Dole, R. B., 243.
Dolomite, 150.
217.
R., 745.
J. F., 808.
salt,
Donald,
Springs, Colo., 309.

Douglas, J., 475, 620.
Douglas Island, Alas., 693, 694.
Dow, A. W., 136.
Doughty
Dowling, D. B.,
Downs, W.
Emley, W.
Emmons,
E., 2O7.
S. F., 441, 474, 482, 498, 499, 500,
501, 592, 619, 634, 655, 673,

746, 771.
H., 334, 406, 443, 452, 457,
477, 481, 499, 500, 617, 619,
620, 655, 673, 677, 745, 746,
747.
Enargite, 568.
England, barite, 316; clay, 182; coal, 52;
cornish stone, 324; feldspar, 324; fluorspar, 332; fuller's earth, 338; gypsum,
255; iron, 548; limestone,
164; salt,
225; siderite, 559; tin, 816.
F.
228.
E.,
Englehardt,
Emmons, W.
Dismal swamp, Va., 12.

Disseminated ore deposits, 473.
Domes,
Don, J.
837
17, 21, 65, 68, 135.

F., 353.
Dragoon, Ariz., 823.

Drake, N. F., 40.
Dresser, J. A., 307, 308, 412, 749.
Drysdale, C. W., 620.
Ducktown, Tenn., 477, 478, 610.
Duluth, Minn., 323.
Dumble, E. T., 67, 748.
Dunkard sand, 96.
Dunmore, Alberta, 115.
Dunn, E. M., 786, 788.
Durham, Eng., 332.
Durley, R. J., 68.
Dyscrasite, 772.
Engler, C., 81.

Eno, F. H., 207, 208.
Enstatite, source of talc, 408.
Eosine, 229.
Epigenetic ore deposits, 434.
Epperson sand, 96.
Erythrite, 795.
Erzberg, Styria, 548.
Estelle, Ga., 371.
Estevan, Sask., 51.

Eton, Ga., 315.
Euboea, Greece, 356.

Eureka, Nev., 434, 671.
Everett, Wash., 784.
Evergreen, Colo., 329.
Everton, Ark., 341.
Fahlband, 472.
Earth's crust, average composition, 435.
Fairbanks, Alas., 735.

Fairbanks, H. W., 321, 746.
Fairburn, S. Dak., 338.
Fairview, 111., 333.
Fallon, Nev., 242.
Falun, Swe., 573.
Faribault, E. R., 705, 825.
East Broughton, Que., 306.

Ebano, Mex., 111.
Farrell, J. H., 497.

Farrington, O. C., 390.
Eckel, E. C., 167, 207, 208, 209, 228, 250,

259, 283, 297, 377, 564, 566, 746.
Eddingfield, F. T., 771.
Edmonton, Alberta, 111.
Edwards, M. G., 758.
Fawns, S., 818.

Fay, A. H., 318, 818.
E
Eagle River, Colo., 671.
Ealcle, A. S., 747.
Egypt, onyx, 154.

Eilers, A., 788, 809, 810.
Ekersund-Soggendal, Nor., 524.

Elba, Italy, 548.
Eldridge, G. H., 134, 136, 184, 283, 421.
Elizabeth sand, 97.
Elk garden coal, 32.

Elkhorn, Mont., 573, 686.
Elk sand, 97.
Ellis,
E. E., 417.
Elliston, Mont., 275.

Ells, R. W., 136, 282, 620.
El Oro, Mex., 730.
Eluvial placers, 434.

Ely, Nev., 585.
Embolite, 676.
Embreeville, Pa., 323.
Emerald, 383.
Emerson, B. K., 793.
Emerson, Ga., 372.
Emery, analyses, 294.

occurrence, 294.
Feldspar, analyses, 323.

Canada, 324.
commercial grades, 326.
England, 324.
occurrence, 321.
production, 324.
properties, 321.
references on, 327.
United States, 322.
uses, 324.
Felsobanya, Hungary, 729.
Fenneman, N. M.,
134, 135.
Fenner, C. N., 499, 592.

Ferberite, 822.
Fergus County, Mont, 385.

Ferguson, H. G., 501, 812, 818.
Ferguson, Okla., 224.
Fermor, L. L., 758, 768.
Fernekes, G., 618.
Ferrier,
W.
F., 283.
Ferromanganese, 768.
Fertilizers, apatite, 260.
greensand, 279.
guano, 279.
kainite, 260.
INDEX
838
Freiberg, Sax., 462, 672, 826.

Freibergite, 676.
Fertilizers, nelsonite, 260.

phosphate of lime, 260.
French Broad
potash, 238.
production, 280.
See Phosphates,

production, 339.
properties, 337.
references, 340.
United States, 338.
uses, 339.
Fifty-foot sand, 96.

Finch, J. W., 500.
platinum, 805;
tin,
811.
Finlayson, A. M., 485, 486, 498, 614, 729.

Fisher, C. A., 186, 422.
Fitch, R. S., 825.
Five Islands, X. S., 315, 316.
G
for building, 148, 149.
Fla., 338.
Gabbro,
Flagstone, 158.
Flat Run sand, 97.
Flat Top coal field, 34.
Fleck, H., 825, 827.
Gadsden County,
GafTney,
Gale, H.
Flint, 391.
clay, 176.
pebbles, 295.
Florence, Colo., 83, 108.

Florida, clay, 180; fuller's earth, 338: peat,
8; phosphate, 263.
Fluorite.
See Fluorspar.
Fluorspar, analyses, 333.
Canada, 332.
loreign deposits, 332.
occurrence H 327.
origin, 329.
production, 333.
properties, 327.
references on, 334.
United States, 327.
uses, 332.
Foerste, A., 185, 283.
Fohs, F. J., 66, 318, 334.
Foothills belt, Calif., 613.
Forstner, W., 134, 778.
Fort Defiance, Ariz., 384.
Fort Dodge, la., 250, 253.
Fort Scott, Kas., 190, 197.

Forty Mile Creek, Yukon, 693.
Foundry sands, analyses of, 335.
S. C., 811, 814.
S., 228, 231, 235, 237, 243, 283,

362, 619, 809, 827.
622.
Galena,
Galicia, ozokerite,
118;
petroleum, 113;
salt, 225.
Galleys, N. Mex., 8.
Gallup, F. L., 337.
Galpin, S. L., 184, 327, 370, 751, 758.

Gangue minerals, 429.
Gantz sand, 96.
Gardner, J. H., 67, 185.

Garfias, V. R., Ill, 133.
Garnet, as gems, 383.
occurrence, 291.
United States, 291, 383.

uses, 291.
Garnierite, 795.
Carrey, G. H., 592, 747.
Garrison, F. L., 498, 566.
Gary, W. Va., 9.
Gases, magmatic, 444.
Gas sand,
Gas.
Gaston County, X.
Gellivare,
Gem,
France, antimony, 781; barite, 316; bauxite, 755; bismuth, 787; bituminous rock,
124; buhrstone, 284; coal, 52; flint, 295;
gypsum, 255; hydraulic lime, 189; iodine,
237; kaolin, 182; limestone, 164; limonite, 556;
marble, 153; phosphate, 280;
salt, 225; talc, 410; tuff for building, 164.
Frank, Alberta, 50.
Franklinite, 621, 759.
Frazer delta coals, Brit. Col.,

Frazer, P., 4, 19, 65.
Fredericktown, Mo., 147, 795.

Free, E. E., 243.
C., 315.
Gautier, A., 500.

Gaylussite, 242.
Geijsbeek, S., 184.
physical tests, 336.

production, 337.
references, 337.
requisite properties, 335.
United States, 337.
Fourche Mountain, Ark., 120.
Fox, R. W., 499.
Fraleck, E. I,., 404.
96.
See Natural Gas.
definition, 334.
Freeport, Pa., 229.

Freestone, 158.
N. C., 315.
Fuller, M. L., 419, 421, 438.

Fuller's earth, analyses, 338.
uses, 279.
Fielclner, A. C., 65.
Fifth sand, 97.
Finland, granite, 146;
district,
Fuchs, E., 497, 781.

Fuel ratio, coal, 6, 19.
Sweden, 517, 518, 519.
Ido., 660.
Gems.
See Precious Stones.

Genthite, 795.
George, R. D., 108, 746, 825.
Georgetown, Colo., 702.
Ido., 276.
Me., 323.
Georgia, asbestos, 300; barite, 315; bauxite, 751; clay, 179, 180; corundum, 293;
fuller's earth, 338;
gold, 691; granite,
147; graphite, 349; hydraulic lime, 189;
manganese, 761, 764, marble, 153; mica,
368; mineral paint, 371; natural cement
rock, 196; ocher, 372; phosphate, 278;
pyrite, 403; serpentine, 156; slate, 162;
talc, 409.
Georgian Bay, Can., 111.

12.
German
silver, 652, 804.
Germany,
barite, 316; bauxite, 755; bismuth, 787; buhrstone, 286; cadmium,

788; clay, 179; coal, 52; cobalt, 803;
copper, 603, 605, 609; fluorite, 332; fuller's earth, 338;
hydraulic lime, 189;
INDEX
Germany,
kaolin, 182; limonite, 556; lithographic stone, 355; salt, 225; silver-lead,
672; tin, 811; zinc, 651.
Gibson, A. M.,66.
G.K., 231, 421.
H. P., 499.
Gilpin County, Colo., 704.
Gilpin, J. C.,340.
Gillette,
Glass sand, analyses, 341.

composition, 340.
Grand Etang Harbor, N. S., 253.

Grand Rapids, Mich., 250, 253.
Granite, Canada, 162.
for building, 144.
United States, 342.

See
97.
Grain, in granite, 144.

Grande Cote, La., 223.
mechanical analyses, 342.

physical properties, 341.
production, 343.
references, 343.
salt.
Gordon sand,
Goroblagodat, Russia, 518.
Gouge, 468.
Gould, C. N., 134, 136, 168, 228, 259, 422.
Gouverneur, N. Y., 153, 403.
Grabau, A., 213, 217, 228, 247, 259.
Grahamite, 118.
Gilsonite, 121, 126.

Glasser, M. E., 803.
Glauber
Gordon, C. H., 134, 168, 566, 619, 656, 748.
Gosling, E. B., 136.

Gossan, 476.
Gossan Lead, Va., 611, 612.
Gothite, 503.
Gottschalk, V. H., 478, 501.
Gersdorffite, 795.
Gibbsite, 750.
Gilbert,
839
Sodium Sulphate.
United States, 146.
Glendale, Mont., 671.

Glendive, Mont., 8.
Glendon, N. C.,411.
Glenn, L. C., 67, 414, 421, 500.
Glenravel, Ireland, 751.
Glens Falls, N. Y., 192.
Globe, Ariz. ,301, 600.
Godfrey, Ont., 305.
Golconda, Nev., 767.
Gold, dredging, 734.
fissure veins, types of, 676.
hot spring deposit, 442.
occurrence, mode of, 676.
ore minerals, 675.
placers, 730.
solution in weathering, 480.
uses of, 737.
value of ores, 488.
Goldfield, Nev., 708, 713.
Gold-silver ores, Black Hills region, 684.
Canada, 705.
classification, 678, 680.
contact metamorphic, 686.

copper bearing, 679.
Cordilleran region, 681.
Cretaceous-Tertiary, 682.
deep vein zone, 686.
dry or siliceous, 679.

Eastern crystalline
belt,
685.
extraction, 680.
foreign deposits, 705, 729.
free-milling ores, 680.
geologic comparisons, 685.
intermediate depth, 695.
lead bearing, 680.
placers, 678, 730.
production, 738.
refractory ores, 680.
uses
of, 148.
Grant, U. S., 620, 657, 747, 748.

Grape Creek, Colo., 521.
Graphite, amorphous, 344.
analyses, 344, 348.
Canada, 349.
crystalline, 344.
industry, 351.
occurrence, 345.
origin, 345.
production, 352.
properties, 344.
references, 353.
uses, 351.
Grass Valley, Calif., 696.
J.
S., 208, 318.
Grasty,
Graton, L. C., 452, 456, 485, 499, 565, 617,

618, 619, 656, 674, 691, 747, 748,
818, 819.
Grays Summit, Mo., 341.
Great Gossan Lead, Va., 550.
Great Plains, Can., coal, 50.

Great Salt Lake, Utah, 21 f, 226.
Greece, magnesite, 356;
marble, 153, 164;
lead-silver, 673.
Greenland, cryolite, 332, 750.

Greenockite, 641, 788.
Green River coal basin, Wyo., 42.

Green River, Utah, 826.
Greensand, analyses, 279.
occurrence, 279.
Greensboro, N. C., 521.

Greenville, Va., 557.
Gregory, H. E., 167, 392, 421, 498.
Gregory, J. W., 737.
Greisen, 812.
Greisenization, 488.
Grimsley, G. P., 168, 186, 208, 209, 228,

230, 259, 297, 343, 564.
seleniferous, 729.
Griqualand, Africa, 307.

Griswold, L. S., 134, 297.
Griswold, W. T., 84, 95.
shallow depth, 708.
von Groddeck,
siliceous, 679.
Grossularite, 290.
Ground water, composition, 442.
Grout, F. F., 20, 60, 66, 185, 186, 434, 499,
619.
Grubenmann, A., 457.
Guanajuato, Mex., 730, 813.
secondary
enrichment,
677.
Tertiary veins, 684.
United States, 681, 686,

695, 708.
weathering
of,
zinc ores, 680.
677.
A., 451.
INDEX
840
Hedley, Brit. Col., 449, 686, 687.

Heikes, V., 745.
Helena, Mont., 629.
Helen Mine, Ont., pyrite, 404.
Guano, 279.
Gulf of Suez, 216.
Gumbo,
176.
Gunther, C. G., 497.

Gypsite, 244, 248.
analyses of, 253.
Gypsum, analyses, 253.
calcining of, 256.
Canada, 253, 254.
difference from anhydrite,
Hematite, 503.
Lake Superior
24.6.
earth, 248.
gypsite, 248.
impurities in, 246.
occurrence, 244.
origin, 246.
production, 256.
properties, 244.
United States, 249.
uses, 255.
Gypsumville, Man., 253.
region, 525.
paint, 371.
United States, 524.
Henegar, H. B., 318.
Henry ton, Md., 323.
Herald, F. A., 259.
Herkimer, N. Y., 319.

Herrick, C. L., 259.
Hershey, O. H., 673.
Herstein, B., 243.
Hess, F. L., 259, 353, 362, 400, 746, 780,
783, 784, 786, 788, 794, 809, 810,
818, 819, 822, 825, 827
Heusler's alloys, 768.
Hewett, D. F., 297, 321, 400, 748, 827.
Hice, R. R., 67, 168, 209, 565.
Hicks, W. B., 243.
Hill
End, N. S. W., 706.

M., 619, 704, 746, 747.
Hill, J.
Haenig, A., 353.
Hill, R. T., 182, 217.
Hafer, C., 771.

Hager, D., 133.
Hillebrand, W. F., 778, 809, 827.

Hills, R. C., 746.
Hills, V. G., 825.
Hindostan stone, 287.
Hager,
L., 218.
Hague, A., 500, 674.

Halm, F. F., 228.
Haile Mine, S. C., 691.
Hainesport, N. J., 336.
Hale, D. J., 208.
Haley, D. F., 783.
Hinds, H., 66.

Hirschwald, J., 167.
Hitchcock, C. H., 68, 185.
Halifax, Mass., 8.
Hall, J., 545.
Hobbs, W. H., 390, 566, 825.

Hocking Valley coal, 32.
Hodge, E. T., 500.
Hodges, Jr., A. D., 805.
Hamilton, N. D., 25, 65.

Hancock, Md., 190, 196.
Hoen, A.
W.
Va., 341.
Hanna, G. B., 747.
341.
N.
J.,
Hanover,
N. M., 788.
Harder, E. C., 452, 513, 548, 565, 566, 695,

758, 768, 771, 793.
Hardin County, 111., 328.
Hardman, J. E., 567.
Hardwick, Vt., 145.
Harker, A., 446.
Harkins, W. D., 788.
Harney Peak, S. Dak., 815.
Harris, G. D., 66, 133, 134, 136, 217, 223,

228, 396, 421.
Hartford, W. Va., 229.
Hartnagel, C. A., 566.
Hartshorne coals, 41.
Hartville district, Wyo., 536.
Hastings County, Qnt., 292, 298.
Hastings, J. B., 500, 501.
Hatch, F. A., 695, 737.
Hatscheck, E., 499.
Hauraki, N. Z., 729.
Hauteville, France, 164.
Haworth,
66,
134, 135, 208, 228, 421,

645, 656.
Hayes, A. O., 567.
Hayes, C. W., 65, 66, 67, 136, 283, 318, 377,
497, 566, 752, 754, 758, 771.
Hazeltine, K., 66, 67.
Headden, W. P., 309.
E.,
Hoeing,
J. B., 134, 136.
B., 355.
Hofer, A., 81, 87, 133.
Hoffman's blue, 229.

Holden, R. J., 565.
Holland, T. H., 758.
Holston, Va., 222.
Homestake Mine,
Hook, J. S., 283.
S.
Dak., 690.
Hopkins, O. B., 308.

Hopkins, P. E., 748.
Hopkins, T. C., 167, 186, 327, 412, 414, 566.
Hopper, W. E., 124, 136.
Horseneck sand, 96.
Horton sand,
Horwood, C.
Hoskins, A.
96.
B., 737.
J.,
370.
Houghton, Mich., 606.

Hovey, E. O., 136, 414.
Howes Cave, N.
Y., 190.
Hoyt, S. L., 658.

Huasteca, Mex., 111.
Hubbard, G.
Hubbard, L.
D., 134.
L., 228.
Hubnerite, 822.
Hudson, J. G. S., 68.
Huelva, Spain, 404.
Humboldt, A., 79.

Humphreys, R. L., 167, 207.
Hundred foot sand, 96.
Hungary, gold-silver, 729; iron,
Hunt, T. S., 81, 87, 395.
Hunt, W. F., 400.
518.
INDEX
Iron Springs, Utah, 512.
Irvine oil sand, 97.
Hunter, J. F., 400, 746.

Huntington, Ark., 8.
Huntley, L. G., 70, 91, 111, 116, 135.
Irving, J. D., 486, 499, 501, 603, 656, 673,

746, 748, 771, 825.
Irving, R. D., 466, 565, 619.
Italy, antimony, 781; barite, 316; bituminous rock, 125; iron, 548; marble, 164;
mercury, 775; pumice, 288, sulphur,
398; talc, 410; tufa, 150.
Ithaca, N. Y., 220.
Ivanhoe, Va., 551.
Ivigtut, Greenland, 332.
Hurry Up sand,
96.
Hutchinson, L. L., 134, 136
Hydatogenesis, 446.
Hydrargillite, 751.
Hydraulic cements, 188.
lime, 189.
limestone, 150.
Hydrozincite, 621.
Hypogene, 481.
Ichthyol, 126.
Idaho, asbestos, 302; gypsum, 252;
phate, 275; silver-lead, 660.
Idaho Springs, Colo., 443, 702.
Iditarod, Alas., 736.
phos-
Idria, Austria, 775.

coal, 37; fluorspar,
lead-zinc, 648;
328;
glass sand, 342;
natural cement rock, 196; petroleum, 99;
pyrite, 403, tripoli, 413.
Ilmenite, 819.
Impregnations of ores, 473.
Illinois, clay, 179, 180;
Impsomite, 120.
India, diamond, 295;
ese, 768;
gold, 695;
mangan-
salt, 225.
Indiana, cement, 202; clay, 179, 180; coal,

36; foundry sand, 337; glass sand, 343;
limestone, 150; natural gas, 114; petroleum, 99; pyrite, 403; whetstones, 287.
Indicators, Ballarat, 706.
Ingalls, W. R., 655, 656.
Inverness, N. S., 24, 47.
d'Invilliers, E. V., 67, 343, 545.
Iodine, Chili, 237.
in phosphate, 237.
seaweeds, 237.
Silesian zinc ore, 237.
sources, 237.
lodyrite, 676.
Iowa, clay, 180; coal, 38; gypsum, 250;
lead-zinc, 648; limonite, 556.
Irelan, W., 208.
Ireland, bauxite, 755.
Iridium, 808.
Iridosmine, 805.
Iron Mountain, Wyo., 520, 521, 522.
Iron Ores, Canada, 524, 546.
contact-metamorphic
841
deposits,
513.
Jack, 621.
Jackson, A. W., 167.
Jackson, Mich., 336.
Jacobs, E. C., 412.
Jacquet, J. B., 659.
Jagerfontein, Orange Colony, 382.
Jamestown, Colo., 329, 333.
Jamesville, N. Y., 190.
Jamison, C. E., 135.
Japan, antimony, 781; coal, 52; sulphur,
393.
Jarvis, R. P., 566.
Jasper, 526.
Jasperoid, Missouri, 642.
Jefferson County, Mont., 671.
Jeffrey, E. C., 12, 65, 82.
Jellico district, Tenn., 35.
Jenney, W. P., 645, 656.

Jennings, La., 107.
Jerome
district, Ariz., 611.
denned, 2.
Joachimsthal, Austria, 787, 803, 826.
Joggins, N. S., coal, 47.
Johannesburg, S. Afr., 737.
Johanngeorgenstadt, Sax., 787, 826.
Johnson, B. L., 618.
Johnson, D. W., 5, 67, 91, 116, 390, 421.
Johnson, H. R., 231.
Johnson, R. H., 91, 133.
Johnson, R. P., 70.
Johnston, R. A. A., 825.
Johnston, W. D., 184.
Johnstown, Pa., 8.
Jones, Jr., E. L., 619, 746.
Jet,
Jones, J. C., 259, 566.

Jones, R. H., 308.
Jones sand, 96.
Joplin Area, Mo., 640.
Joseph, M. H., 809, 825.
Josephinite, 806.
Julien, A. A., 144, 167.
foreign, 517, 548, 556, 559.

hematite, 524,
impurities in, 503.
limonite, 548.
Kalgoorlie,
magmatic
Kalmus, H. T., 805.
segregations, 517.
magnetite sands, 523.

minerals, 502.
production, 559.
pyrite, 559.
references on, 564.
reserves, 563.
siderite, 558.
United States, 505, 520, 524, 537,

549.
weathering, 479.
K
W.
Austral., 695.
Kame
sand, 97.
Kamiah, Ido., 302.
Kanawha, W. Va., 226.
Kanolt, C. W., 756.
Kansas, cement, 202; coal, 40; natural
cement rock, 197; gypsum, 248, 252;
natural gas, 115; petroleum, 102; salt,
222.
Kansas City, Kas.,
39.
Kaolin, analysis, 178.
INDEX
842
Kubel,
Kaolin, Europe, 182.
Kapnick, Hungary, 729.
Karaboghaz
Gulf, 211, 215, 216.
Katalla field, Alas., 109.

Katz, F. J., 745.
Kay, G. F., 805.
Kedzie, G. E., 673.
Keele, J., 186, 749.
Keenburg, Tenn., 751, 754.
Keener sand, 96.
Keene's cement, 252, 256.
Keith, A., 412, 512, 565, 656.
Kellogg. L. O., 746, 825.
237, 306, 308, 353, 400, 440,
441, 451, 472, 489, 497, 499, 500,
501, 512, 518, 520, 558, 565, 592,
618, 619, 620, 628, 656, 745, 805,
808.
Kenmore, O., 220.
Kennedy, W., 566.
Kentucky, barite, 313; bituminous rock,
124; clay, 180; coal, 37; fluorspar, 327;
foundry sand, 337; guano, 279; limonite,
natural
556; lithographic stone, 355;
cement rock, 197; natural gas, 114; phosphate, 278; siderite, 559; whiting, 376.
Kermesite, 780.
Kern County, Calif., 122.
Kern River, Calif.. 102.
Kern River field, Calif., 104.
Kerosene shale, 125.
Ketchikan district, Alas., 588.
Keyes, C. R., 237, 677, 745, 747.
Kieselguhr, 318.
Kiesente, 214.
Killas, 816.
Kimball, E. B., 807.
Kimball, J. P., 564, 748.
Kimbeiley, S. Air., 382.
Kindle, E. M., 297, 566.
King, F. H., 437.
King, F. P., 296.
Kingsgate, X. S. W., 788.
Kingston, Ont., 324.
Kirchoffer, W. G., 422.
Kirk, C. T., 619.
Kemp,
J. F.,
Kirksville, Mo.,
9.
Kiruna, Sweden, 517, 519.

Kithil, K. L., 827.
Klockman,
F., 451, 497, 603, 614.
Klondike, Alas., 735.

Mo., 341.
Knight, C. W., 308, 493, 498, 567, 800, 805.
W.
C., 135, 168, 186, 231, 259, 422,
Knight,
748.
Knopf, A., 448. 452, 618, 673, 674, 778, 806,

809, 818.
Knox County, Me.,
573.
Kohler, E., 499.

Kolar gold field, India, 695.
Koontz coal, 32.

Kootenay district, B.
Kramer, G., 81.

Kramm, H. E., 259, 771.
Kraubat, Styria, 792.
447, 497, 499, 524, 548, 569,
672, 673, 705, 708, 729, 730, 775,
803, 811, 816.
P.,
B., 185, 208,

F., 390.
343
Kunzite, 385.
Kwinitza, B. C., 225.
Kyshtim, Russia, 614.
Lacroix, A., 758.

Lafayette, Colo., 8.
Lake Abitibi, Ont., 694.
Lake Ainslie, X. S., 315, 316.
Lake beds. See Potash, 239.
Lake Charles, La., 396.
Lake City, Colo., 636, 673.
Lake Larder, Ont., 694.
Lake, Mono, 211.
Lake of the Woods, Ont., 694.
Lakes, A., 167.

Lake Sanford, X. Y., 521.
Lake Tahoe, 211.

Lake Umbagog, X. H., 319.
Lake Valley, X. M., 671.
Lamp
black, 116.
Lancashire, Eng., 548.

Lancaster, Pa., 432.
Landes, H., 68, 135, 209.
Land
pebble, phosphate, 266.
Lane,
plaster, 256.
A. C., 37, 66, 208, 220, 228, 230, 247,
422, 440, 500, 608, 618, 619.
Laney, F. B., 168, 619, 620, 747.

Larcombe, C. O. G., 695.
Laredo, Tex., 45.
Larsen, E. S., 243, 334, 400, 447, 500, 501,
655, 673, 746.
von Lasaulx, A., 395.

Latouche Island, Alas., 613.
de Launay, L., 435, 438, 482, 497, 498, 614,
745, 787.
Laur, F., 758.

Laurium, Greece, 673.
Lautarite, 237.
Lawrenceville, X. Y., 190.
Law-son, A. C., 451, 497, 586, 619.
Layman, F. E., 208.
Lead, cadmium in, 788.
desilverized, 624.
ore minerals, 622.
production, 652.
secondary enrichment. 486.
United States, 638.
uses, 651.
value of ores, 488.
Lead, S. D., 690.
Leadville, Colo., 630, 767.
Lead-zinc ores, contact
metamorphic
de-
posits, 626.

C., 671.
Korea, graphite, 351.

Kragero, Norway, 819, 821.
Krusch,
S. J., 355.
Kummel, H.
Kunz, G.
high-temperature veins, 629

intermediate depth, 630.
occurrence, 622.
origin, 623.
production, 652.
references on, 655.
sedimentary rock deposits,

636.
shallow depth ores, 636.
INDEX
Lead-zinc ores, United
States,
624,
626,
648.
Le Conte,
J.,
weathering, 623.
438, 778.
843
Linnaeite, 795.
Linton, 111., 9.
Lipari Islands, 290.
Lithographic stone, analyses, 354.
properties, 354.
references, 355.
sources, 355.
Lee, Mass., 153.

Lee, W. T., 353, 400, 421.
Lehigh, N. D., 8.
Okla., 9.
Lehigh Valley, Pa., 192, 198.
Leighton, H., 184, 259.
Leith, C. K., 451, 452, 497, 513, 534, 548,
558, 564, 565, 619, 695, 771.
Lenher, V., 745.
Leonard, A. G., 67, 656.
Lepidolite, 354.
Le Roy, O. E., 590, 593, 620, 674.
Rock, Ark., 148.

Rocky Mountains, Mont., 453.
Livermore, Calif., 767.
Locke, A., 747.
Lode, denned, 471.
Lesher, C. E., 67.
Loess, 176.
Lesley, J. P., 65, 67, 168.

Lesquereux, L., 65, 81, 84.
Lester, Ark., 8.
Logan, W. N., 185.
Little
Cottonwood Canon, Utah,
Calif., 319.
Lopez, Pa., 9.
Lord, E., 747.
Lord, N. W., 65, 67, 208.
Los Angeles, Calif., 101, 102.
Lost Hills, Calif., 102.
Lost River, Alas., 811.
Louderback, G. D., 390.
Loughlin, G. F., 185, 674, 825.
Louisa County, Va., 401.
Louisiana, limonite, 556; natural gas, 115;
petroleum, 106; salt, 217, 223; sulphur,
Lignite, analyses, 8.
Canada, 49.
properties of, 2.
Lignitoid, 14.
Lima, O., 71.

Lime, 187.
396.
hydraulic, 189, 194.

properties of, 188.
raw materials (U. S.), 193.
references on, 207.
sand, 96.
uses of, 205.
Louisville, Ky., 190, 197.

Lowe, E. N., 565, 566.
Lowell, Vt., 299.
Lower Kittanning coal, 32.
Low Moor,
Va., 557.
changes in burning, 188.
Lucas, A. F., 133.

Ludington, Mich., 220.
Lumberton, N. J., 335, 336.
characteristics, 149.
Lundbohm,
compositions, 187.
Luossavaara, Swe., 517.

Lupton, C. T., 135.
Limestones, analyses
Canada,
187.
164.
of,
for building, 149.

United States, 150.
uses, 154.
varieties of, 149.
Ger., 124.
Limnetic coals,
Limonite, 503.
H., 518.
Luxembourg, limonite, 556;
iron, 558.
Luzenach, France, 409.

Lyell, C., 65.
Lyman, B. S., 620.

Lyon Mountain, N.
13.
Y., 511.
Canada, 556.
gossau deposits, 550.
mountain ores, 553.
Oriskany, 555.
residual clay, 552.
residual deposits, 549.
origin, 554.
types of deposits, 549.
United States, 549.
valley ores, 553.
Lincoln, F. C., 441, 498, 618, 745.
Lincolnton, N. C., 815.
Lindeman, E., 567.
Lindemuth, J. R., 243.
Lindgren, W., 436, 440, 441, 443, 447,
452, 456, 457, 474, 489,
497, 498, 499, 501, 518,
603, 618, 619, 620, 656,
695, 737, 745, 746, 747,
778, 786, 809, 825.
Lines, E. F., 208.
668.
Little
Little
Lompoc,
Lethbridge, Alberta, 50.

Leverett, F., 421, 422.
Lewis, J. V., 168, 390, 434, 619, 793.
Lewiston, Pa., 341.
Limmer,
Litharge, 651.
Lithium, 354.
Lithophone, 317, 652.
Mabery, C. F., 133.
McAdamite,
756.
MacAlister, D. A., 497.
McCalley, H., 66, 566.

McCallie, S. W., 66, 167, 283, 421, 546, 566,
746.
451,
493,
574,
674,
748,
McCarty, E. T., 686.

McCaskey, H. D., 619, 778.
McConnell, R. G., 567, 620, 749.
McCourt, W. E., 68, 167.
McCreath, A. S., 565.
McDonald, P. B., 825.
McFarland, D. F., 73.
MacFarlane, J., 65, 67.
MacFarlane, T. M. M., 390.
Mackenzie, G. C., 567.
McKittrick, Calif., 102.
Macksburg sand, 96.

MacLaren, M., 695, 745.
McLean, T. A., 749.
INDEX
844
McMurray,
Mansfeld, Ger., 609.

Mansfield, G. W., 276.
Alberta, 225.
Mace, C. N., 400.

Mace, Ido., 600.
Madagascar, graphite, 351.
Mapimi, Mex., 784.

Marble, as building stone, 149.
Madden, G. C., 018.

Madoc, Ont., 332.
Canada,
Madoc Township,
definition, 150.
foreign, 104.
104.
characteristics of, 149.
Ont., 410.
Madrid, N. Mex., 9.
Magdalena, X. Mex., 626.
United States, 152.

uses, 154.
F., 185.
Magdalen Islands, Can., 253.

Magmatic emanations, 444.
Magmatic ore bodies, form, 432.
Marbut, C.
metals in, 432.

Magmatic copper, 572.
iron, 505, 517.
segregations, 430.
Magmatic water, 440.
in ore formation, 441.
Magnalium, 756.
Magnesite, analyses, 359.
California, 356.
dolomite type, 356.
origin, 356.
production, 300.
properties, 355.
references, 302.
serpentine type, 356.
uses, 360.
Magnetite, Adirondack region, 505.
non-titaniferous deposits, 505.
origin of, 511.
sand, Quebec, 524.
sandstone, 523.
titaniferous, 520, 524.
concentration
tests,
522.
United States, 504.
Maine, copper, 573; feldspar, 323; granite,

graphite, 349;
Martin, G. C., 00, 133, 208, 283, 746.

Maryland, building stone, 149; clay, 179,
180; chromite, 791; coal, 32; diatomaceous earth, 320; feldspar, 323; glass
sand, 342; granite, 147; hydraulic lime,
189; magnesite, 350; marble, 153; natural
cement rock, 190; serpentine, 156;
siderite, 559;
molybdenum, 793;
Mason, W.
Malcolm, W., 135, 749.

Maicolmson, J. W., 673.
Maiden, \V. Va., 230.
stone, 158.
Massillon, O., 341.
Matanuska, Alas., 48.

Matehuala, Mex., 592.
Mathews, E. B., 168, 208, 327, 793.
Matson, G. C., 185, 283, 421.
Matthew, W. D., 282.
sand, 96.
Mavari, Cuba, 558.

Maynard, G. W., 793.
Maynard, T. P., 208.
Mead, W. J., 558, 754,
758.
Calif., 447, 593, 692.
Valley, Calif., 766.
Means, A. H., 746.
Medicine Hat, Alberta, 50, 81, 115.
Medicine Lodge, Kas., 252.
Lake,
Mediterranean, Usiglio's experiments, 212.
Mallock, G. S., 68.

Maltha, 117, 122.
Mammoth seam, Pa., 23.
Manganese, analyses of, 764.
Meerschaum, 362.
analyses, 363.
references on, 364.
classes of ore, 759.

effect on gold enrichment, 677.

iron ores, 767.
ore minerals, 758.
origin of ores, 760.
prices, 769.
production, 768.
reference, 771.
silver ores, 767.
United States, 760.
uses, 768.
value of ores, 489.
Manganite, 759.
Manistee, Mich., 220.
Manitoba, gypsum, 255; limestone,

Manjak, 121, 126.
Mankato, Minn., 190.
Va., 229, 239.
Massachusetts, emery, 294; granite, 147;

marble, 153; peat, 8; pyrite, 403; sand-
Meadow
Meadow
slate, 162; tourmaline, 386.

Malachite, 568.
Malay Peninsula, tin, 816.
slate, 102.
Marysvale, Utah, 242.
Maxton
Magnus, H., 296.

Mahoning sand, 96.
Mahren, Austria, 351.
147;
Marienberg, Sax., 826.

Marion, Ky., 333.
Marksville, Va., 521.
Marlow, Okla., 253.
Marquette, Mich., 528.
Marquette range, 528.
Marsters, V. F., 308, 309.
Meggen, Ger., 316, 403.

Meigs coal, 32.
Melaconite, 568.
Melrose, Mont., 275, 276.
MendeljefT, D., 79.
Mendenhall, W. C., 421, 500.
Menefee gas sand, 97.
Mercer coal, 37.

Mercur, Utah, 700.
Mercury, extraction, 776.
164.

ore minerals, 771.
origin, 772.
production, 777.
references on, 778.
United States, 772.
uses, 776.
Merrill, F. J. H., 228, 230, 259.
INDEX
Merrill, G. P., 167, 168, 169, 184, 237, 297,
306, 309, 337, 340, 745.
Merwin, H. E., 618.
Merz, A. R., 243.
Mesabi range, 532.
Mesler, R. D., 414.
Metacyst, 464.
Metallogenetic epochs, 492.
Metallographic study of ores, 496.
Metals, deposited from springs, 442.
in rocks, Lindgren's estimate, 436.
in rocks, Vogt's estimate, 435.
occurrence in rocks, 434.
Metasome, 464.
Metasomatism,
in ores, 462.
Mexico, Ky., 315.

Mexico, antimony, 781;
coal, 52;
copper,
592; gold-silver, 686, 730; lead-silver,

673; mercury, 776; onyx, 154; opal,
384; petroleum, 111; tin, 813, 816; tuff,
164;' sulphur, 393.
Meymac, France, 787.
Mezger, A., 748.
Miami,
Ariz., 600.
Miargyrite, 676.
Mica, books, 364.
Canada, 368.
mining, 368.
occurrence, 364.
production, 369.
properties, 364.
references, 370.
structure, 365.
United States, 365.
uses, 368.
Micanite, 369.
Micarta, 369.
Michigan, bromine, 229; calcium chloride,

230; cement, 202; coal, 37; copper, 606;
graphite, 349; grindstones, 286; gypsum,
250; hematite, 528; salt, 220; sandstone,
158; whiting, 376.
Michipicoten district, Ont., 534.
Mickle, G. R., 136.
Microcline, 321.
Middle Kittanning
Midway,
coal, 32.
Calif., 91.
Utah, 118.
Miles, Mont., 8.
Miller, A. M., 318, 353, 377, 656.
Miller, W. G., 296, 308, 493, 498, 567, 749,
778, 801, 805, 819.
Millerite, 795.
Milwaukee, Wis., 190, 196.
Minas Geraes, Brazil, 548, 695, 768.
Mine Hill, N. J., 627.
Minera, Tex., 43.
Mineral charcoal, 14.

Mineral Creek, Ariz., 601.
Wash., 783.
Mineralizers, 446.
Mineral paint, analyses, 371.
hematite, 371.
ochre, 371.
production, 376.
references, 377.
shale, 375.
siderite, 374.
slate, 375.
845
Mineral Point, Mo., 312.

Mineral water, 422.
Mineral wax, 118.
Minette, 556, 558.
Mineville, N. Y., 260, 508, 512.
Mine
waters, 442, 443.
Minnesota, artesian water, 418;
building
stone, 149; feldspar, 323; granite, 147;

limonite, 556; hematite, 532; slate, 162.
Mirabilite, 231.
Mirage, N. Mex., 333.
Miser, H. D., 390.
Missanagra, Peru, 826.
Missionary Ridge, Tenn., 753.
Mississippi, clay, 180.
Missouri, barite, 310; cadmium, 788; clay,

179, 180, 181; coal, 38; glass sand, 342;
marble, 153; lead, 646;
granite, 147;
nickel-cobalt, 795; tripoli, 412; zinc, 640.
Mitchell sand, 96.
Moa, Cuba, 558.
Moffat, E. S., 65, 745.
Moffit, F. H., 618.
Molding sand. See Foundry Sand.
Molybdenite, 793.
Molybdenum, occurrence, etc., 793.
Monazite, analyses, 378.
Brazil, 378.
occurrence, 377.
production, 379.
properties, 377.
references, 379.
United States, 378.
uses, 379.
Montana, coal, 44; copper, 573, 593; goldsilver, 686; granite, 148; graphite, 349;
gypsum, 252; lead, 646; lead-silver, 671;
magnetite, 523; phoslimonite, 556;
phate, 275; sapphire, 385; silver-lead,
658; volcanic ash, 290.
Monte Amiata, Tuscany, 775.
Monte Cristo, Wash., 470, 698.
Montello, Wis., 147.
Monterey,
Calif., 319.
Monterey County,
Calif., 46.
Montpelier, Ido., 275.

Montroydite, 771.
Moore, E. S., 406, 567, 659.
Moore, P. N., 66.

Moore, R. B., 827.
Moosehead, Pa., 373, 374.
Moose Mountain, Ont., 517, 547.
Morenci, Ariz., 451, 577.
Moresnet, Belgium, 439, 650.
Morgantown sand,
Morro Velho mine,
Moses, A.
J.,
96.
695.
778.
Mother of coal, 14.

Mother Lode, Calif., 695.
Moundsville sand, 96.
Mountain sand,
Mount
Mount
Mount
Mount
Mount
Mount
Mount
96.
Tasmania, 816.
Crawford, S. Aus., 821.
N.
792.
Z.,
Dun,
Holly Springs, Pa., 414.
Bischoff,
Lyell, Tas., 614.
Margaret, W. Aus., 695.

Morgan, Queensland, 706.
Mt. Pisgah sand, 96.
Mount Pleasant, Tenn., 267, 277.
INDKX
SIC.
Moyle, H
('
Mull, pent.
Miilliiu.
MM
Mllllcr,
Mmicy,
I'll
I...
1
1.
,1
.1
Mni|.li\
l.l-
n.
....
)-
M.VHOIC.
HIM
r,.
.11.
:,!,., III,
.'ISO,
7iM
70
Niiplen yellow, 78'.'

.'(IK. :MiV
Nitnon. |.' I,
\Mlllilllll ill-Mil. I. Nl'V
New
IM.
'.'I
:,
eoinpoillllln
nil.'
.en. "I. 7I>
..
!.
ML.
icn
...
IIMI'I,
yirl.l
i.l
-..,.
Ml
u.
Muni
Neihurl,
Neill,
,1
Nelnn
87
iixli,
New
MO
Ia7
ulnle,
IftS,
HIM
/enliind,
078,
7:i
lulc.
111;',
wlielMonen, a87,
408,
nine,
III),
I!
iM.I.I
I,"*
Sft.
me
ll.nl I.....
(jold plueern,
mui.l,
iniiitiielile
7'.MI,
lift
.1
NlcliolU,
Nickel liloom, 70ft
Nickel, CiiniidH, 807
til
II.
7la,
i-l.ii.inile,
..ilvcr.
pliiliniiin, 80ft
Niccollle. 7Uft
ftail,
Ml
niiiieniU, 7IM
her foreiitn drp..il.

prodiicllon, MO I
ri'ferencci on. MOft
I'niled Hlulen, 7tift
ol
Mill
'.'(HI
SOft
Hll.'l
lle, SOU
'mini v, \'n
Neldini, \V. A
117,
\. '..mi.
-ii
'i.n,
(
viilue of HICK,
SU'.'.
|K!1.
771
(Mil
Col
Nickel 1'lnle Mine, Mill

ft7
Nieliiux. N. M
-,
;iaa, founiliy unil,

tt\n* mind, Ilia, uruplia I1,
liydiiiillic Inn.-,
UVpnillli.
in iiiiMiU,
1171, 7117
feliUpm,
itiirncl, '.MM
811
|,l..p. .II.
Ni'liiankli, vi.lriinir
KM;
;iaii,
llftll
..f,
,||
..
alia, eeinenl rock,

diiilonmeeoiin euilli,
MM,
MiiiidMone,
M,
well iHCNnnre,
Nlllllllll ll.rk
ft'J;
sii,
iron, ftOft, ftai, ftlM, lime, i" i. o..ll
Hlonen. aMI, iiiineiiil pninl, 1171, niihiiid
in. MI rock, MM),
ii '.i ML.
UHH, III; pi
I... I. inn
Oft;
1011,
null.,
aail,
pyrile,
II'.
eoul,
lunitMen,
Ofttl,
SluicH.
KMIIlll,
|,|
ilecienne,
......
...
II.
in.
I.I.
in, 711
...
pieaine
nilver,
I..
rlil.Mlllr.illi.il
prnperi
I,,,,
at) I;
He, Kill;
n.
nl
,'i..'
hlniinilh, 788;
\V,il.-..
KII.I.
emery,
7M
ill.
Ciiiiiiiln.
'.'.M.
lliri|UOi*|l,
vuiiiiiliiiin, sail
York, eenienl,
.'1117;
Applillirliilin
11,111.
dlnlmmi,
illilllynCN
.,
ai7,
H|,ll,
.111.1.
,,
.1
Soiiil.
New
V.'ll
I
ifH". iiri-iiliiuliilii.li, H|
in.
asa,
jftu,
r.ia, ftiin, flnn,
dlMlicl. Vll
|.'
a?8, aMM
col.ull,
Nulive iirnenic, 7811

Nnii\e cnppci depoHiiB, HIM
I.I
lute,
lllU',
8a
Nlllllllll
ins,
iiriinliiin, Mail;
NCW.OIII,
Nnuylmnyii. llunuiiry,
Niihiiul
i:m,
Iron,
'J7U,
Meici.. ImunIlK, 755; cudiiiluni, 78N;

ci.ni.ia, copper, r, MII, not. lluompiii, :iai>;
UMinei, :is;i, uruplille, IUO; Kvpmiin, aft'.';
iron. Mil, lend nil ver, 071; lend nine. liaO;
New KIM
,
ii
nlulo,
:r/r..
New
00ft
Trim*
ureeii mind,
ilia,
piilnl,
u.c, nait
;i;i7, :H;I. ;i:.;i, ;i77, 4011,
NIIUVIIK,
7711
7811
:iH|
COD.
-il.. il.-
Newiiin.i.
:.,!
...I....
IM,
Ark
00
,,...,.
Miinil,
Ml.
ion.
IWft
Idl Hi, Ciill(
.lemey, cenienl. 'JO'Ji ely, 180, copper,

1.,
,i,,,l,M-;r,
IIS.
Inuiiilry nnnd, :t:i7;
ltln
111, III). CIA
Nil,
Aim
....ml.
Miinny,
M,,
Ml.
W
I
I,.
.
1.1
1171
MiiiclilKi.ii,
Mm.
M MI
>'"
Will
M.I.I...
New
New
Ofttt.
0:1
OMO.
Nevnilii,
iiiiliiiinnv,
7HII,
IM.IIIH, "'M. i-i,ppei, f,SA;

70S, 711. KvpMiiin, arc;
.p.l.
:>!.
mill, '.'Ml;
p|....iin.,i.
l.i.-.iniilli.
(/nlil (.liver, IIMII;
Nil.-:.
Midi
iniiniciiiiexe, 7(17;
Mien,
()., 1141,
HIM),
ver lend. 1171.
nil
7NO,
|,,,|,,.l,.
'.'.)',{.
luiiKnien. NX'I
Nevndii ( 'ily, Clilit 11(11)

Neviuln Ci.iinly. 'ulil HIM',
,
NeviiiB,
New
.1
Aliiinden,
Newl.env,
.1
iHUl
( 'iilif
7711
17. 81.
oil
Rliiile,
iri.n.MIl,
aft;
uiiliinniiy,
rliiy,
niihiiiil (tu,
pelioleiiin,
III,
la,
I
|fi;
...,,.|
Mime. Hll
New
'I'liuilxk,
Curollim,
iron,
54.
mien,
liurile, Illft,
mo nil/lie.
clipper, 110ft.
lliiinpM'iire, uiirnel, aill;
HCVl lii-xli. IM-H. a87.
N V
uritliiln.
KIN;
<
.1
170, ciml,
conili-
|iurnel, all;
iiiiiiiiinee. 700.
1(811,
1178. phimphiile,
mippliire,
a78,
.'18ft;
.'.I'M.
content,
ittkiilH,
II .481.
Norlon,
Norwiiy, copper, ft71l,
Norwood.
,.,
cliiy,
copper, Oil.
rnliy, HMft; minilMone, IftM,

tide, 40M; tin, 814.
ft48.
717
itrunile, 147,
Illll,
llllft,
807.
enieiidil.
'.Mill;
Mr,,-,,. 1,1.-. .,.'l.
.inn.
ftllft,
Kiiiixlu,
cliroinlle, 701;
aiiri;
-.in.
t*7
('. ;i7l,
'.-...I.
Hold,
N H
OftM
Nifthni
North
Ni-wfoiinilliiiHl. KiindiiiK pelililcn,

<
II
II
Nnrll. CiiMle,
Ciiledonm, ehroinile, 7ta

nickel, su.i
New
New
NiUe,
.l.ini.
HnuiRwirlt, ullierlile, IIH,

Ml.. lie,
7HO.
lunliliiiu
Ilia.
ar.r.;
Nixxen, A
I.,.
.i.lll
Nineveh mind,
lift,
Cl.'l
New
ItypMiiin.
Nlclnun 'rorl.rook
iiOiij
eoul, 44
OOfi;
IHllMIIIII..
feldnpur, JJ84;
S/|
Oil.
Noviiciilile, aM7.
Novn
Hcoliii,
Miilin.i.iiv.
780,
l.urile,
Mil);
NIIVII Hi'nlltt, liiillillhK "Inn",
''ml,
47|
HIIIII,
UM,
Iron, ft4H|
(;
H,
Itt'Ji "liiy,
70ft
it'il'l,
IKSJi
DIM
H47
iiiulyliili'imiii,
47H
I|I>|IM*|IN, it'iMAii,
liyillulli. iin.il
,y|-
ViU,
OH,
(llM'll.'ll, (I
>..n
(I,,
,1,'
'iiinnlii,
HI't'lllTI'IM 1 ' 1
1(7 I,
O'llurcit,
ili'ltni'il,
IMllM'HlU iMllH'll,
|i.
"N, ./,!?,'
I'luy,
;i;i7,
',,
yr,, OHli.
',
WO,
I'lllnH'lo,
ri'llli'lll,
IH'J)
ulninl.
'"
'
ii-,l- ni,i
"
i,
01 -inliiiHiM,
,441
", 4)40,
HH,
M7;
K'ti'iil",
i
I|(|MI|I,
I2f;
lllllHMll
Iff,
IC.II",
vv|(u)/i,
ii'i^,
I'l
||i-li)l-Mlii,
M4,
')(),
ic.il.l,
"
KM,
Ml'
i-.y,, 7ftl.
<!.,
1,1,1" Mllrt,
4W
""i.
H,
"
Vlll/'ll(l)/> HK|I.
IIIKIII, HO'i,
II
11,11
4ft/)
<>Jr'Hll<'il', N. M.,
,..',
I'
47U
UN7
OIlMll/tM'H,
rock,
"'i'
'
Hlll|/Illl|l>
4NI
MM'lll,
nil,
!
mi, 407
HiTiDlillll V
'
mill,
170, IHO, I'iml, !IU; fniiinliy
."'
icn, 1)4, lift) (c-iim<. i.u.i, :H;I,
ini'h,
107; KiliMlnliiM"*, UHO)
/(-
'
liM'Ifn,
OH,
4W
ll'.
I.IM..I.I.
M'fiiri'iiiM'4
'' Mi'-'iil
4Ktl
I'|'|)|M|IKV I'lmiiM"*, 4/fi
rill. '111111
Olllll,
IllHlllnu, 444;
Mh
;ir,;i
<'
,,H,
|,f
urn
I'l".
MUIIM,
,|||Ti'M>lll
mlilUcil HUH", 4711
I7X
|!nll>"l HliiloM,
|,
oilKlli, 4140
|iii,|,"Hli'M of, !47I,
ol(.i'i."i.ui',
i'|tl"|Hll|iih'
.1
III.H|II
H7U
nriicln,
4M
7H
(ll'lll'l, lllllllVMI'n,
(Jgll
(fill
41)11
lMHWIMMlt
I
till, ifilluii,
llii|iH'MiuillMii, 4714,
x'J4,
IHIfti
i'n|i|i"c,
Mil N
OH,
HW,
OI,'/)I<|HKH,
NY,
771,
oii.,(ni..,
,,,,!., I,.,,,
IH,
I,,, ,|,
.Inn
I,,,,,,
474
-,
4MI
i/f,
;l,till,Hl>.
'',
.(',,
;w^;
iii
Witt',
/'(I
:
,
LI
,,,
;H;(,
/*.i,
inntll'
I,'
I.
.',.'(
,(,,/, |, M
V>M,W\, M\IIHH,
!.
li/ic ni..i,<
/',l,
(|
MH,
I"
!/
i.
(.'
III,
"ii/i,
(//(,. In.
1(1.1' -.
|/l<niu(i;,
H<('/,
(/,
y'Ci.
//'
|;y>/<<,
..
',|,|i
-I
i/,
MI
I/I'
Al'^",
4<M,
Ihii'lttuwii,
,
MH,
I',,,
'\HH
i,
kllOlHHM, U V,;
'
"./
Wi
...),',-,,
tttb*mt*wMHriH
I
,,1,1
V,,,
in
/c0
Mttif M*, tMtt ,WH.
I';)}
('-. 'i
<>,., Ill,
,/>/),
'.'.^
I.I'.
Mii'lriii.H>i. '.''
i,
l/"clw ..... I, H
W>,
t,tu,,i>iin,
I'/,
tl'/l
My, W"v
4
fill
Mill,
>"'!'
'
'.
^rt
It ,i
',!'!
\l\
,,
ttAH*, 1/Hglll lit, iflft,
M*,,*,
t'nM
V,,,
Wt,
i'
4^/, 4'44
4W,
4M,
'ttHHiHH, H*t
III
*,f>,
M,
>w wnyiW**, 4/JO/
*<i'^
\,
W,
'>'
t
I'M,
Mb,
t'44,
V,t.
m,
tM,
\t*,
INDEX
848
Ouray, Colo., 470, 728.
ite
Outcrops, coal, 22.
quartz, 391.
paint,
374;
shale
paint,
375; vein
Penokee-Gogebic range, 530.
ore, 476.
Overbeck, R. M., 619.

Ovitz, F. K., 65.
Owens Lake,
Calif., 241
Oxidized ore zone, reactions in, 479.
Ozark Region, lead zinc deposits, 639.
Ozokerite, 118, 126.
Penrose, R. A. F., 279, 283, 390, 499, 501,

564, 566, 677, 745, 764, 771.
Peppel, S., 168, 209.
Pepperberg, L. J., 656.
idot, properties, 384.
kins, G. H., 168.
manent
swelling, in stone, 143.
rett, L., 809.
Pachuca, Mex., 730.

Pack, F. J., 674.
134, 136.
sian Gulf, 247.
u, vanadium, 827.
Petersburg, Va., 336.
Petersen, W., 277.
Petit Anse, La., 223, 225.
rine,
Pagliucci, F. D., 778.

Paige, S., 390, 565, 619, 748.
Pala, Calif., 354.
Palladium, Xev., 806.
Palladium, occurrence and use, 808.
Palmer, C., 499, 745.
Pandermite, 236.
Panuco, Mex., 111.
Paola, Kas., 102.
I.,
Petroleum, accumulation, 89.

Alaska, 109.
analyses, elementary, 71.
analyses of, 74.
anticlinal theory, 87.
Pappoose sand, 96.

Paraffin, native, 118.
Paralic coals, 13.
Appalachian
Pardee, J. T., 283, 297, 321, 748.

Parian marble, 164.
Canada, 110.
France, 255.
J.,
92.
classification of sands, 87.

Colorado, 108.
Paris, Ark., 9.
Park,
field,
asphaltic base, 71.

California, 102.
composition, 70.
497.
distillates, 73.
Park City, Utah, 664.

Parker, E. W., 54.
Parker coal, 32.
Parks, H. M., 168.

Illinois field, 99.
life of well, 91.
Mexico, 111.
Parks, W. A., 169.

Parmelee, C. W., 68, 337.
mid-continental field, 102.

Parr, S. W., 19, 25, 65, 66, 414.

Parral, Mex., 730.
Parsons, A. L., 283, 749.
Parsons, C. L., 68, 338, 340, 827.
Partinium, 756.
Passau, Bav., 344, 350.
Patagonia, Ariz., 242.
Patten, H. E., 262.
Ohio-Indiana Field, 98.

optical properties, 71.
origin of, 79.
paraffin base, 70.
pool, 83.
production, 127.
properties of, 70.
references on, 133.
rock pressure, 85.
sand, 83.
sands, yield of, 91.
Patton, H. B., 390, 746.

Patronite, 825.
Peace River, Fla., 263.
Pearce, R., 827.
Pearcite, 676.
Pearl Creek, X. Y., 225.
Peat, analyses of, 8.

analyses of layers
shales, 125.
specific gravity, 72.
sulphur in, 71.
summary
of fields, 110.
Texas, 106.
in, 1.
United States, 91.
origin, 61.
distribution, 91.
production, 64.
uses, 63.
uses, 116.
Pebble phosphate, 265.

Pebbles, grinding, 295.
Peck, F. B., 209, 412.
Peckham, S. F., 133, 136, 137.
Pegmatite dikes, 446.
Pennsylvania,, clay, 179, 181; chromite,

791; coal, 29, 31; building stone, 148,
156, 158, 162; feldspar, 323; glass sand,
342;
348;
lead-zinc, 639;
graphite,
limonite,
555; magnesite, 356; magnetite,
512; manganese, 766; millstones,
nat284; natural cement rock, 196;
ural gas, 114; nickel, 795; ocher, 373;
petroleum, 95; phosphate, 278; Portland cement, 198; siderite, 559; sider-
viscosity, 72.
well pressure, 85.
wells, life of, 91.
Wyoming,
W.
109.
C., 185, 228, 243, 318, 321, 400,

406, 566.
Philippines, coal, 52.
Philipsburg, Mont., 686.
Phillips. F. C., 81, 497.
Phillips, W. B., 67, 68, 135, 137, 283, 406,
620, 745, 748, 758, 778.
Phlogopite, 364.
Phoenix, B. C., 590.
Phosphate, analyses of, 272, 276.
blanket deposits, 268.
Phalen,
INDEX
Phosphate,
collar deposits, 267.
cutters, 268.

hard rock, 263.
impurities, 262.
land pebble, 266.
minerals in, 261.
origin of, 262.
rim deposits, 267.
United States, 263.
Phosphorite, 261.
Pi?tou, N. S., coal basin, 47.
Piers, H., 819.
Pignerolles, Italy, 409.
Pike sand, 96.

Pike Station, N. H., 287.
Pilbarra,
W.
Aus., 695.
Pipe clay, 176.

Pirsson, L. V., 390, 747, 786.
Pishel, M., 65.
Pitchblende, 825.
Pitch length, 474.
Pitkaranta, Finland, 452, 811.
Pittman, E. F., 788, 803.
Pittsburg, Pa., 226, 229.
Pittsburg coal, 24, 32.

Pittsville, Va., 554, 557.
Placer deposits, 433.

Placer gold, Alaska, 734.
Placers, gold, amount gold obtained from,
679.
California, 731.
dredging, 678.
dry, 730.
eluvial, 730.
eolian, 730.
gold, 678, 730.
marine, 731.
minerals in gold, 731.
Russia, 737.
size of gold in, 731.
stream, 730.
Victoria, 737.
Yukon Ty., 736.
Placers, platinum, 805.
tin, 814.
Plagioclase, 322.
Plasterco, Va., 222.
Plaster of paris, 256.
Plasticity of clay, 172.
Platinum, Canada, 807.
composition, 806.
occurrence, 805.
production, 807.
references on, 808.
United States, 806.
uses, 807.
value of ores, 489.
Plumas County, Calif., 573.
Plumbojarosite, 806.
Pneumatolysis, 446.
Pocahontas coal field, 34.
Pogue, J. E., 390, 619.
Pohlman, J., 208.
Point Sal, Calif., 319.
Polargyrite, 676.
Polybasite, 676.
Polyhalite, 214.
Pomeroy,
Pomeroy
Poole, H.
O., 220, 222, 229, 230.

coal, 32.
S., 68,
Pope County,
318.
328.
111.,
Pope, F. J., 499.

Pope's Creek, Md., 319.
Popocatepetl, Mex., 393.
Porcupine, Ont., 694.
Porter, H. C., 65.
Porter, J. B., 68.
Porter, J. T., 340.
Porterville, Calif., 3o6, 359.
Port Graham, Alas., 46.

Portland cement, analyses, 193.
formula, 192.
properties of, 191.
United States, 197.

Portland stone, 164.
Portugal, tungsten, 824.
Posepny, F., 438, 441, 489, 497, 499.
Posnjak, E., 618.
Potash, alunite, 242.
brines and bitterns, 239.
igneous rocks, 242.
kelp, 243.
monzonite, 243.
Portland cement, 243.
saline lake beds, 239.
Pot
clay, 176.
Potonie, H., 12, 65.

Pottsville coal, 32.
Powder river coal basin,
Pozzuolan cement, 188.
Pozzuolano, Italy, 188.
Prairie City, Ore., 796.
Prather, J. K., 203.
Wyo.,
44.
Pratt, J. H., 296, 306, 309, 318, 334, 370,

379, 390, 393, 412, 793.
Precious stones, production, 388.
properties, 380.
references, 390.
Premier mine, S. Afr., 382.
Prescott, B., 497, 565.
Pretoria, Transvaal, 382.
Primary minerals, in ores, 481.
Prime, F., 209, 565.
Prince William County, Va., 401.
Prince William, N. B., 780.
Prince William Sound, Alas., 613.
Prindle, L. M., 745.
Proctor, Vt., 153.
Producer gas, analysis of, 79.
Propylitization, 486.
Prosser, C. S., 185.
Proustite, 676.
Providence, R. I., 348.
Przibram, Bohemia, 469, 672.
Psilomelane, 758.
Puente Hills, Calif., 102.
Pulpstones, 287.
Pumice, 288, 290.
Pumpelly, R., 466, 608.
Punjab, ludia, 225.
Purdue, A. H., 167, 278, 283, 390.
Purdy, R. C., 185.
Purington, C. W., 737, 746, 809.
Put-in-Bay, L. Erie, 393.
Pyrargyrite, 676.
Pyrite, analyses of, 402, 403.
Canada, 403.
.
INDEX
850
Pyrite, foreign deposits, 404.
occurrence, 400.
origin, 402.
production, 404.
properties, 400.
references on, 406.
requirements of, 401.
United States, 401.
uses, 404.
Pyrolusite, 758.
Pyromorphite, 622.
Pyrope, 383.
Pyrophyllite, 411.
Pyrrhotite, effect on gold

tion, 677.
(nickel), 795.
and
silver migra-
Redwood,
B., 82, 133.
Regulus, defined, 782.

Reid, H. F., 498.
Reid, J. A., 618.
Renwick, W. G., 167.

Replacement, criteria
of,
465.
in ores, 462.
Republic district, Washington, 729, 809.

Retsof, N. Y., 225.
Re wold, Va., 784.

Rhode Island, granite,
147,
graphite,
Rice, W. N., 392.

Rich, J. L., 565.
391.
quartzite, 391.
references on, 392.
uses, 391.
vein, 391.
Quebec, apatite, 261; asbestos, 302; building stone, 162; cement, 202; chromite,
791; clay, 181; copper, 613; gold, 694;
marble,
limonite, 556;
graphite, 349;
164; magnetite, titaniferous, 524; mica,
368; molybdenum, 794; ocher, 374; pysandstone, 164; slate, 164;
rite, 404;
tungtitanium, 820;
soapstone, 410;
sten, 824.
Quebec City, Can., 164.
flint,
Richmond, Va.,
5,
819.
319, 335.
Rickard, F. 827.
Rickard, T. A., 500, 501, 619, 673, 706, 745,
825.
Rico, Colo., 670.
Riddles, Ore., 796.
Ridgway, Va., 367.
Ries, H., 68, 167, 170, 171, 184, 185, 186,
208,321,337,340,758.
Rift, 144.
Riggs Station, Calif., 409.

Rio Tinto, Spain, 403, 614.
Ritchie County, W. Va., 118
Robellaz, F., 745.
Quercy, France, 280.

Queretaro, Mex., 384.
Robinson, H. H., 137.

Rockbridge Co., Va., 784.
Rock Glen, N. Y., 239.
Rock phosphates. See Phosphates.
Quicksilver, 771.
Quisquerite, 827.
Rock Run, Ala.,

Rock salt, 212.
Queensland, bismuth, 787; gold, 706; tungsten, 824.
R
sand, 97.
Ragland
Raible, Austria, 651.
Railroad Valley, Nev., 242.
Rainy Lake district, Ont., 694.
Rambler mine, Wyo., 806.
Rammelsberg, Ger., 603.
Ramona, Calif., 386.
oil
Rankin, G.
Ransome,
S., 192.
F. L., 474,
348.
Rhodesia, chromite, 792.

Rhodochrosite, 759.
Richards, R. W., 276, 283, 400.

Richardson, C., 122, 136, 422.
Richardson, C. H., 309.
Richardson, G. B., 135, 228, 400, 783, 786,
Quarry water, 142.

Quartz,
Red Mountain, Ala., 543.

Redstone coal, 32.
481, 485, 486, 498,

500, 618, 619, 656, 660, 673, 674,
746, 747, 778, 825, 827.
Rapikivi granite, 146.
Raton coal field, Colo., 42.
Raton, N. M., 349.
Ravicz, L. G., 500.
Ray, Ariz., 601.
Ray, J. C., 619.
Raymond, R. W., 566.
Reading, Pa., 373.
Read, T. T., 498.
Real del Monte, Mex., 730.
Realgar, 783.
Red Beds, copper in, 609.
Redjang Lebong, Sumatra, 729.
Redlich, K., 362.
Red Lodge, Mont., 44.
Rdckton,
111.,
751, 765.
335.
Rogers, A. F., 259, 481, 498, 501, 619.

Rogers, G. S., 283.
Rogers, H. D.,'4, 793.
Rolfe, C. W., 185.
Roman cement, 190.
Roros, Norway, 573.
Roscoelite, 825.
Roseland, Va., 821.
Rosen, J. A., 337.
Rosendale cement, 190.

Rosendale, N. Y., 191, 196.
Rosita, Colo., 329, 333.
Ross, C. S., 566.
Ross, W. H., 243.
Rossland, B. C., 593.
Routivare, Swe., 524.
Rowe, J. P., 66, 168, 297, 353, 825.
Rubellite, 386.
Ruby, 384.
Ruddy, C. A., 68, 422.
Rudersdorf, Ger., 191.
Ruhm, H. D., 267.
Rumbold, W. R., 816.
Rundall, W. H., 778.
Runner, J. J., 825.
Runs, Joplin district, 642.
Rusk, Tex., 557.
851
Russell, I. C., 208, 545, 566.
Russellville, Ark., 9.
coal, 52;
copper,
Russia,, asbestos, 307;
609, 614; gold placers, 737; iron, 518;
manganese, 768; petroleum, 113; platinum, 807; salt, 225.
Rutile, occurrence, etc., 819.
Rutland, Vt., 153.
Rutledge, J. J-, 546, 566.
Sagger clay, 176.

Saginaw, Mich., 9, 38, 226, 239.
Saginaw Valley, Mich., 220, 230.
St. Charles, Mo., 35.
St. Eugene mine, Moyie, 659.
St. Ignace, Mich., 250.
St. Louis, Mo., 35.
St. Nicholas, Pa., 9.
Urbain, Que., 524, 820.

Sala, Swe., 659.
St.
Sales, R., 500, 596, 619.

Salina, Kansas, 253.
Salines, 210.
Barbara,
Calif., 122.
Clara Valley, Calif., 102.

Eulalia, Mex., 673.
Maria, Calif., 102.
Maria field, Calif., 104.
Santander, Spain, 651.
Santa Rita, N. Mex., 586.
Sap, quarry, 143.
Sapphire, 385.
Sardinia, zinc, 651.
Saskatchewan, Can., clay, 181;

Saucon Valley, Pa., 639.
Savage, T. E., 422, 566.
Schaller, W. T., 778, 825.
Scheelite, 822.
de Schmid, H., 283, 334, 370.
Schneeberg, Sax., 787, 803, 826.
Schofield, S. J., 674.
Schrader, F. C., 67, 134, 243,
746, 747.
Schrauf, A., 772, 778.
Schreiber, H., 63.
coal, 49.
656,
745,
Schuchert, C., 13.
Schuermann, F., 484.

Schultz, A. R., 231, 283, 748.
Schuylkill Co., Pa., 9.
Schwartz, E. H. L., 737.
Schwarzenberg, Ger., 811.
Schwatzite, 771.
-
Salisbury, Conn., 557.

Sail Mountain, Ga., 298, 300.
Salmon River, B. C., 253.
Salt,
Santa
Santa
Santa
Santa
Santa
Canada, 225.
desert theory, 216.
extraction of, 225.
geologic distribution, 218
in brines, 211.
in sea water, 211.
marshes, 211.
occurrence, 211.
origin of, 212.
production, 226.
references on, 228.
rock, 212.
types of occurrence, 210.
United States, 218.
uses, 226.
Salt sand, 96.
Salton Lake, Calif., 224.

Saltville, Va., 225, 226.
Scotland, coal, 52; granite, 164;
Scranton,
Searle, A. B., 182.
Searles Lake, Calif., 241.
Pa., 9.
Wash., 45.
Secondary ore minerals, 481.
Seattle,
Seger, H., 322.

Selenite, 244.
Selenium, occurrence and uses, 809.

Sellards, E. H., 263, 283, 340, 421.
Selvage, 468.
Semianthracite coal, analyses of, 9.
properties of, 4.
Senarmontite, 779.
See Meerschaum.
Sepiolite.
Serpentine, for building, 154.
San Cristobal, Colo., 242.
Severn River, Md., 342, 361.
Sand, chromite, 791.

foundry, 334.
Sericitization, 487.
glass, 340.
gypsum, 253.
magnetite, 523.
monazite, 377.
Sandberger, F., 434, 497.
Sandstones, building stonos, 156.
Canada, 164.
properties, 156.
United States, 158.
uses of, 159.
varieties, 158.
Sandusky, O., 192, 252, 253.
421.
Sanford, S.,
Sanford Hill, N. Y., 520.
San Francisco Bay, Calif., 211.
San Francisco district, Utah, 668.
San Joaquin Valley, Calif., 102.
San Jose, Mex., 592.
San Juan, Chile, 448.
San Juan Region, Colo., 722.
San Pedro, N. Mex., 452.
oil
125.
Seward Peninsula,
placers, 735.
Seyssel, France, 124.
for
191.
Shale,
cement,
Shaler, M. K., 134, 185.
Shaler, N. S., 68, 565.

Shannon, C. W., 565.
Sharon coal, 32.

Sharwood, W. J., 745.
Shaw, E. W., 135.
grit, 284.
Sheafer, A. W., 265.
Shear zones, 474.
Shedd, S., 168, 186.
Sheep Creek, Calif., 409.
Sheet ground, zinc, 642.
Sheeted zones, 474.
Shepard, E. M., 422.
Shepherd, E. S., 441, 498.
Shoots, ore, 468.
Shungnak, Alas., 791.
Siberia, coal, 52; graphite, 345.
Sicily, sulphur, 398.
Shawangunk
shale,
INDEX
852
Siderite, as ore, 558.
iron ore mineral, 503.

as paint, 374.
United States, 559.
Siderite paint, analyses, 375.
Siebenthal, C. E., 168, 208, 297, 413, 414,
642, 656, 789.
Sierra Mojada, Mex., 673.
Sigginspool, 99.
Silesia, cadmium, 788; zinc, 651.
Silification, 487.
Silver Bell, Ariz., 586.

Silver City, N. Mex., 755.
Silver-lead ores, Canada, 659, 671.
deep vein zone deposits,
658.
foreign deposits, 659, 672.
intermediate depths, 660.
occurrence, 658.
references, 673.
shallow
depth
deposits,
673.
United States, 658, 660,

673.
Silver ores, fissure veins, types of, 676.
occurrence, mode of, 676.
minerals, 675.

uses
of,
738.
value of ores, 488.

See gold-silver.
Silver Peak, Nev., 686.
Silver
Plume, Colo., 702.
Silverton, Colo., 470, 727.

Singewald, J. T., 564, 565, 813, 816, 819.
Sinter, tin bearing, 814.
Sjogren, H., 517, 518, 573, 659.
Skutterudite, 795.
Skyros marble, 164.
Slag cement, 189.
Slate, Canada, 164.
properties of, 159.
United States, 160.
uses, 162.
Wales, 164.
Slichter, C. S., 416.
Slickford sand, 96.
Slip clay, 176.

Sloane, E., 168, 186, 297, 370.
Slocan district, B. C., 824.
SlossoTi,
F., 135, 259.
.
Smaltite, 795.
Smith, C. D., 134, 135.
Smith, E. A., 167, 184, 207, 283, 353, 421.
Smith, F. C., 748.
Smith, G. O., 66, 67, 345, 353, 422, 656, 666,

674, 747, 748, 794.
Smith, H. D., 501.

Smith, J. K., 827.
Smith, P. S., 353, 618, 745.
Smith, W. D., 65.
Smith, W. S. T., 334, 642, 645, 656.
Smith County, Tenn., 330.
Smith sand,
97.
Smithsonite, 621.
Smock,
Smyth,
J. C., 168,
Jr.,
565, 566.
C. H., 406, 412, 499, 545, 566,
644.
Smyth, H. L., 565.

Snee sand, 97.
Snider, L. C., 186, 228, 259, 656.
Soapstone, properties, 407.
See Talc.
Soapstoiie.
Sodium sulphate, 231.
Soldiers Summit, Utah, 118.
Solenhofen, Bavaria, 355.
Somermeier, E. E., 65, 67.
Somers, R. E., 619.
Sonora, Mex., 346, 351.
Soper, E. K., 185.
Souris coal field, Can., 50.
South Africa, gold, 737.
South Australia, titanium, 821.
South Carolina, clay, 179, 180; gold, 691;

manganese, 766; phosphate, 266; tin,
814.
South Dakota, artesian water, 418; cement,

202; clay, 180; coal, 44; gold, 690, 698;
granite, 148; gypsum, 252; mica, 367;
tin, 815; tungsten, 824.
South
South
South
South
Dover, X. Y., 153.

Glastonbury, Conn., 323.
Platte coal
field, 42.
Stukely, Que., 164.

Spain, copper, 614; garnet, 291; iron, 548,
559; mercury, 775; potash, 238; zinc.
651.
Spatsum, B.
C., 255.
Speechley sand, 97.

Spencer, A. C., 345, 452, 500, 512, 565, 618,
619, 620, 627, 628, 656, 673.
745, 746, 786.
Sperrylite, 805.
Spessartite, 383.
Spezia, G., 395.
Sphagnum, analysis of, 1.
Sphalerite, 621.
Spiegeleisen, 768.
Spilker, A., 81.
Spindle Top, Texas, 106.

Split Rock, N. Y.,521.
Spodumene, 354, 385.

Spores in coal, 14.
Spring Hill, N. S., coal, 47.
Springs, metalliferous deposits, 442.
Spring Valley, Wis., 557.
Spring Valley, Wyo., 109.
Spurr, J. E., 67, 237, 400, 440, 497, 498, 499,
592, 673, 704, 714, 745, 746, 747,
748, 786, 809.
Squaw sand, 96.
Stafford, O. F., 778.
Stannite, 811.
Stassfurt, Ger., 213, 225, 229, 360.
Steamboat Springs, Nev., 434, 439, 772, 773.
Stebinger, E., 565.
Steel, A. A., 318.
Steel, D., 586.
Steidtman, E., 501.
Stephanite, 676.
Sterling, Pa., 9.
Sterrett, D. B., 364, 370, 379, 390.
Stevens, B., 501, 618.
Stevenson, J. J., 12, 16.
Steuart, D. R., 136.
Stewart, C. A., 565, 618, 620.

Stibnite, 779,
Stickney, A. W., 614.
INDEX
Stocks, 472.
Taff, J. A., 5, 66, 68, 122, 134, 137, 208.
Tahoe Lake, 211.

Talc, analyses, 409.
Canada, 410.
France, 410.
occurrence, 407.
origin, 407, 408.
production, 411.
properties, 407.
references, 412.
United States, 407.
uses, 410.
Tampico, Mex., 111.
Tantalite, 810.
Storrs, L. S., 66, 67, 68.

Stose, G. W., 283, 318, 414, 620.
Stray sand, 96, 97.
tin,
45.
Taconite, 526.
Stockwork, 472.
Stoddard, J. C., 377.
Stock, H. H., 67.
Stokes H. N., 745.
Stone Canyon, Calif., 46.
Stone Mountain, Ga., 147.
Stone, R. W., 67, 283.
Stoneware clay, 176.
Stope length, 474.
Storms, W. H., 499.
Stream
Tacoma, Wash.,
853
811.
Streeter, 390.
Strontianite, 392.
Tantalum, occurrencce and
Strontium, occurrence, 392.

uses, 393.
Struthers, J., 406.
Stutzer, O., 65, 282, 353, 390, 395, 448, 497,
498, 517.
Styria, talc, 410.
Subbituminous coal, analyses, 8.
properties of, 2.
Sudbury, Ont., 118, 796, 807.
Suez Bittern Lakes, 216.
Suffield, Alberta, 115.
Sulitjelma, Norway, 403, 573.

Sullivan, E. C., 457, 499.
Sulphide enrichment, 481.
chemistry of, 484.
use, 810.
Tarr, W. A., 80, 133, 620.
Tarugi, N., 771.
Tasmania, copper, 614; osmium, 808;
811, 813, 816.
Tasna, Bolivia, 787.
Taylor, C. H., 422.
Teil, France, 189.
Telluride quadrangle, Colo., 724.
Telluride ores, Colo., 719.
Tellurides, gold, 677.
weathering of, 677.
Tellurium, 810.
Temple, Utah, 826.
tin,
Sulphides, oxidation order, 478.

Sulphur Bank, Calif., 772.
Tenino, Wash., 8.
Ten Mile district, Colo., 671.
Tennantite, 568.
Tennessee, bauxite, 753; clay, 180; coal,
34;
copper, 610; fluorspar, 330; limonite, 556; manganese, 762, 766; marble,
153, phosphate, 267; tripoli, 413; zinc,
Sulphur, in coal, 10.

production, 399.
Terra alba, 256.
conditions governing, 482.

criteria of, 481, 484.
upward, 481.
638.
references, 400.
types, 393.
United States, 396.
uses, 399.
Sumatra, gold, 729.
Sumatra swamp, peat in,

Summerland, Calif., 102.
Summerland field, Calif.,
Sumter,
Terlingua, Tex., 765, 774.

Tesla, Cal., 8, 46.
Tetradymite, 686, 810.
Tetrahedrite, 568, 676.
Texada Island, B. C., 517, 547.
Texas, cement, 202; clay, 180; coal, 45;
granite, 147, 148; guano, 279; gypsum,
252; limonite, 556; mercury, 774; petroleum, 106; sulphur, 396.
Thermopolis, Wyo., 397.
Thetford, Que., 298, 305.
Thies, A., 748.
Thiessen, R., 65.
Thirty-foot sand, 97.
12.
104.
S. C., 338.
Sunnybrook sand,
97.
Sunset, Calif., 102.

Supergene, 481.
Sussex County, N.
Swain, R. E., 788.
Swanton,
J.,
626.
Vt., 153.
Swartley, A. M., 748.

Sweden, copper, 573;
granite, 164;
517; lead-silver, 659.
Sweetwater
district,
N. C., 315.
Switzerland, marble, 164.

Sydenham, Ont., 368.
Sydney, N. S., coal basin, 47.
Sylvanite, 810.
Syngenetic ores, sedimentary, 432.

Syracuse, N. Y., 226.
Syracuse, O., 229.
Tabbyite, 121.
Taber, S., 498, 748, 822.
Taberg, Swe., 524.
iron,
Thomas, H. H., 497.

Thomas, K., 400.
Thompson, A. P., 618.
Thompson, B., 133.
Thompson, Jr., J. D., 26.
Thompson, M., 168.
Thomson, S. A., 695.
Three Rivers, Que., 556.
Thwaites, F. T., 566.
Ticonderoga, N. Y., 344.
Tiemannite, 771.
Tietze, O., 125, 182, 255, 283, 316, 338, 355,
364, 400, 412, 755.
Tin, Alaska, 815.
contact metamorphic ores, 811.
Germany, 816.
INDEX
854
Tin, greisen, 812.
hot spring deposits. 814.
in igneous roeks, 811.
ore minerals, 810.
placers, 814.
production, 818.
references on, 818.
United States, 814.
uses, 818.
value of ores, 489.
veins, 811.
Tincal, 233.
Tintic district, Utah, 666.
Tiona sand, 97.
Tip Top, Ky., 341.
Titanium, Canada, 820.
mode of occurrence, 819
Norway, 821.
ore minerals, 819.
production, 821.
references on, 822.
United States, 819.
uses, 821.
Tiverton, R. I., 348.
Todd, J. Iv, 07, 168, 259.
Tolman, Jr., C. F., 477, 481, 498, 500, 601,
618.
Tonopah, Nov., 714, 809.
Topaz, gem, 385.
Topeka, Kas.,
39.
Torbanite, 125.
Torbrook, N. S., 547.

Toronto, Can., 111.
Tourmaline, gem, 386.
Tovote, W., 618.
Tower, G. W., 656, 666, 674.
Tower
City, Pa., 9.
Transbaikal, copper, 605.
Transvaal, S. Afr., 737.
Turner, H. W., 499, 619, 746, 778.

Turquoise, gem, 386.
Turrentine, J. W., 243.
Tuscany,
Italy, 233.
Tuxpam, Mex., 111.

Twelvetrees, W. H., 809,
Type metal, 651, 781.
Tyson coal, 32.
813.
U
Udden, J. A., 135, 243, 421, 748.
Uglow, W. L., 497.
Uinta basin coals, 42.
Uintaite, 121.
Ulexite, 233.
Ulrich, E. O., 334, 335, 619, 656.
Umpleby, J. B., 674, 747, 805, 819.
Underground waters. See Waters.
Upham, W., 185.
Upper Freeport coal, 32.
Ural Mountains, Russia, 307, 344.
Uraninite, 825.
Uranium, foreign deposits, 826.
ore minerals, 825.
production, 827.
United States, 826.
uses, 827.
Usiglio,
J.,
212.
Utah, antimony, 780; asphalts, 118, 121;

bismuth, 786; cem:nt, 202; coal, 44;
copper, 580, 592; gold, 692; gold-silver,
700; gypsum, 252; iron, 512, 516; oil
shale, 125; manganese, 767; phosphate,
275; potash, 242; salt, 224; selenium,
809; silver-lead, 664, 666; sulphur, 396;
topaz, 385; uranium, 826; vanadium,
826.
Utica,
III.,
190, 196, 198, 341.
Uvanite, 825.
Transylvania, gold-silver, 729.
Trap
rock, 148.
Travertine, defined, 150.

for building, 150.
with barite, 309.
Tremolite, forming talc, 408.

in marble, 149.
Trinidad, asphalt, 121.
Tripoli, analyses, 413.
definition, 412.
origin, 413.
references, 414.
United States, 412.
uses, 414.
Trousdale County, Tenn., 330.

Truscott, S.
J.,
809.
Tuff, building stone, 149.

Tulameen, Brit. Col., 807.
Tulsa, Okla., 102.
Tungsten, Canada, 824.

ore minerals, 822.
production, 824.
references on, 825.
United States, 823.
uses, 824.
Tungstite, 824.
Tunis, Afr., 280.
Turkey, chromite, 792.
Vadose region, 437.

Yadose water, 441.
Yanaclinite, 825.
Vanadium, ore minerals, 825.
Peru, 827.
production, 827.
United States, 826.
uses, 827.Vancouver, B. C., 162.
Vancouver
Island, Can., coal, 50.

Hise, C. R., 437, 438, 482, 489, 497,
498, 499, 534, 565, 619, 645,
656, 771.
Van Ingen, G., 771.
Van 't Hoff, J. H., 247.
Variscite, 388.
Vater, H., 247.
Vaughan, T. W., 68, 137, 340.
Veatch, A. C., 68, 135, 218, 228, 421, 422.
J. A., 396.
O., 185, 758.
Vegreville, Alberta, 115.
Van
Vein bitumens, 117.

Vein material, 466.
Vein systems, 471.
Veins, apex of, 471.
banded, 466.
bedded, 472.
bonanzas
in,
468.
INDEX
Veins, cross, 472.
crustification in, 466.
filling of 472.
fissure, 466.
foot wall, 471.

frozen to walls, 468.
gash, 472.
hanging wall, 471.
high temperature, 447.
classes of, 447.
horse in, 471.
472.
lenticular,
lode, 471.
replacement in, 468.
selvage in, 468.
splitting of, 470.
stringers, 471.
structural features, 468.
855
Warners, N. Y., 192, 203.

Warren, C. H., 318, 567, 822.
Warren, H. L. J., 748.
Warren sand,
148; coal, 45;

tine, 156.
Veitsch, Styria, 356.
Waterford,
coal, 37.
Victoria, gold, 705, 706.

placers, 737.
Virgilina, Va., 601.
Virgin Creek, Nev., 384.

Virginia, arsenic, 784; asbestos, 301; barbauxite, 754; building stone,
ite, 312;
147; clay, 179; coal, 34; copper, 601,
611; diatomaceous earth, 320; graphite,
349; greensand, 279; gypsum, 252; lead,
638; lirnonite, 550, 553; magnetite, 515;
manganese, 761; mica, 367; millstones,
284; natural cement rock, 196; nickel,
795; phosphate, 278; pyrite, 401; salt,
222; soapstone, 407; talc, 409; titanium,
820; tufa, 150; zinc, 638.
Virginia City, Nev., 687, 718.
Vogt, J. H. L., 435, 440, 447, 451, 452, 497,
498, 501, 524, 548, 603, 614, 659,
672, 673, 705, 708, 729, 730, 775,
803,811, 813,821.
Volcanic ash, abrasive, 288, 289.
for cement, 189.
Volcano, emanations from, 444.
W
Wabana, N.
Wad, 758.
F., 546.
Wadsworth, O., 239.

Wadsworth, M. E., 747.
Wages sand, 96.
Waggaman, W. H., 243, 262, 283.
Wagoner, L., 435.
Wagon Wheel Gap, Colo., 329.
Waihi mine, N. Z., 729.
Wales, slate, 164.
Walker, T. L., 825.
Wallace, H. V., 771.
Wllaace, R. C., 259.
Wallace, Ido., 660.
Walther, J., 228.
Wang, Y. T., 480, 655.
Waring, G. A., 421, 422.
serpen-
connate, 438.
ground, 416.
composition, 442.
concentrator of metals by,
437.
in earth's crust, 433.
in igneous rocks, 441.
magmatic, 440.
meteoric, in ore formation, 437, 441.
mine, 442.
mineral, 422.
source of in earth's crust, 437.
underground, 416.
Velardena, Mex., 592.

Vermilion range, 532.
Vermont, asbestos, 300; granite, 147; manganese, 766; marble, 152; scythestones,
287; slate, 162.
Vesuvius, emanations, 444.
gold-silver, 729;
Washington, H. S., 390, 501.

Water, artesian, 417.
Veinstone, 466.
Verne
97.
Warrior coal field, 35.

Warsaw, N. Y., 226.
Washburne, C. W., 85, 90, 91, 133, 134.
Washington, arsenic, 784; building stone,
Water
Water
111.,
336.
gas, analysis of, 79.

table, 437.
Watkins, N. Y., 239.

Watson, T. L., 5, 68, 167, 168, 228, 259,
260, 283, 297, 309, 313,
318, 327, 334, 337, 353,
377, 390, 406, 412, 422,
565, 619, 620, 656, 657,
750, 758, 771, 786, 805,
819, 821, 822.
W.
L., 134, 135.
Watts,
Wausau, Wis., 147.
Wavellite, 414.
Weaver, C. E., 748.
Weed, W. H., 66, 441, 442, 451, 482,
489, 499, 500, 618, 619,
674, 745
747, 786.
Weedon, Que., 404.
F.
825.
Weeks,
B., 283,
Weems, J. B., 185.
Wegemann, C. H., 135.
Weidman, S., 422, 566.
Weigert, F., 247.
Weinschenk, E., 353, 573.
Weld, C. M., 566.
Wells, J. W., 499, 786.
Wells, R. C., 501.
316,
370,
498,
748,
810,
486,
620,
Wellston coal, 32.

Wellston, O., 9.
Wendt,
A., 406.
Werner, A. G., 672.

Wesson, D., 340.
West
Australia, gold, 695.
Westerley, R. I., 147.

West Gore, N. S., 780.
West
Virginia, asphalt, 118; bromine, 229;

clay, 179; coal,
34; glass sand, 342; natural gas, 114;
oil, 94; salt, 222.
Wheaton River district, Yuk. Ty., 780.
Wheeler, A., 185.
Wheeler, H. A., 134, 184, 656, 781.
Wherry, E. T., 827.
Whetstones, 287.
calcium chloride, 230;
INDEX
856
White, D., 13, 14, 16, 22, 65, 67.
White, I. C., 67, 68, 87, 133, 135, 137.
C. A., 657.
C. W., 107, 259, 558, 618.
F. C., 447.
F. !]., 192, 501, 618.
Wulfenite, 793.
Wurtzilite, 121.
T
urtzite, 621.
Wright,
Wright,
Wright,
Wright,
White Channel gravels, 736.

White Cliffs, Ark., 192.
Whitehorse, Yuk. Ty., 502.
White metal, 651.
White sand, 731.
Whiting, 376.
Wyoming,
D., 497.
Whittle, C. L., 185.
Whitney,
J.
Wichita Mountains, Okla., 125, 147.

Wieliczka, Galicia, 225.
Wilder, F., 67, 68, 228, 259.
Wilkens, H. A. J., 748.
Wilkinson Co., Ga., 753.
Willemite, 621.
Willey, D. A., 400.
Williams, G. F., 382, 390.
Williams, G. H., 296.
Williams, I. A., 67, 168, 185, 186, 208, 209.
Williston, X. Dak., 43.
Willmott, A. B., 567.
Willmott, C. W., 825.
Wilmot, Va.,319.
Wilson, A. W. G., 406.
M.
E., 749.
Wilson,
Wilson County, Tenn., 330.
Winchell, A., 185, 564, 825.
Winchell, A. N.,353, 619.
Winchell, H. V., 475, 499, 501, 747.
Winchester, Calif., 357.
Winnipeg, Can., 164.
Winslow, A.,
asbestos, 302; coal, 42; ehromite, 791; gypsum, 252; graphite, 349;
iron, 522, 536;
petroleum, 109; phosphate, 275; platinum, 806; sodium sulphate, 231; sulphur, 397; volcanic ash,
290.
Wyssokaia Gora, Russia, 518.
Yakutat Bay,
Alas., 48.
Yale, C. G., 237, 745.
Yampa coal
field,
Colo., 42.
Yellow Pine district, Nev., 806.

Yellow sand, 731.
Yerington, Nev., 586.
Yogo Gulch, Mont.,
301.
York, Ont., 253.
York
region, Alas., 815.
Yorkshire, Eng., 559.
Young, G.
Young. G.
A., 567, 771, 783.
J., 243, 747.

basin, Alas., 48.
Territory, antimony, 780;
copper, 592; gold, 736.
Yukon
Yukon
coal, 52;
66, 435, 566, 645, 656.
artesian water, 418; building

stone, 147, 149, 158; lead-zinc, 648; limnatural cement rock, 196;
onite, 556;
pyrite, 403; quartz, 391.
Wisconsin,
Wise Co., Va.,
9.
Witherbee, F.
S.,
509.
Zeehan
Wittlich, E.,813.
Witwatersrand,
Woburn
S. Afr., 737.
Sands, Eng., 338.
Wochein, Ger., 751.

Wolff, J. E., 565, 656.
Wolframite, 822.
T
olframinium, 756.
Woodman, J. E., 567.
Wood River, Ido., 453.
Woodruff, E. G., 135, 136, 400.
Woodstock, Md., 323.
Wood tin, 811.
Woodworth,
J. B., 67, 68,
Woolsey, L. H., 297.
Zacatecas, Mex., 730.

Zalinski, E. R., 390, 657.
Zaloziecki, R., 81.
Zanesville, O., 336.
185.
district,
Tasmania, 811, 813.
Ziegler, V., 819.

Zinc, ore minerals, 621.
oxide, 652.
production, 652.
uses, 651.
value of ores, 488.
Zinc.
See also Lead-Zinc.
Zincite, 621.
Zinc ores, origin, Missouri, 644.

weathering, 480, 481.
Zinnwald, Ger., 816.
Zuber, 137.
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ECONOMIC GEOLOGY

JOHN WILEY & SONS,

Building Stones and Clay Products

for Architects, xiii+415 pages, 6 by

Clays: Their Occurrence, Properties and Uses

Prof. Heinrich Ries,

Professor of Economic Geology, University of Virand State Geologist of Virginia, xxvi+722

RIES, A.M., PH.D.

PROFESSOR OF GEOLOGY AT CORNELL UNIVERSITY

FOURTH EDITION, THOROUGHLY REVISED AND ENLARGED

COPYRIGHT, 1905, 1907, 1910,

BRAUNWORTH & CO.

PREFACE TO FOURTH EDITION

While these additions to the text and

the size of the book somewhat, the number of pages is not to be

over one hundred full-page illustrations, formerly bound as inserts,

Survey, and Canadian Department of Mines reports.

have appeared too late to include them, but it

for reading and criticising the manuscript.

for aid in obtaining statistical

Acknowledgments for the loan of new illustrations are due to

The Southern Railway Company; Mr.

CORNELL UNIVERSITY, ITHACA, N. Y.

V. Limes and Calcareous Cements

VI. Salines and Associated Substances

XI. Minor Minerals.

XIII. Underground Waters

XIV. Ore Deposits

XVII. Lead and Zinc

XIX. Gold and

Aluminum, Manganese, Mercury

Diagram showing changes occurring

in passage of vegetable tissue to

under coal beds

Section showing irregularities in coal seam

Section of coal bed, showing the development of a

Map of Pennsylvania anthracite field

Sections in Pennsylvania anthracite field

General structure section of the Richmond basin in the vicinity of

Northern Interior coal field

14. Generalized section of

Map showing distribution of different kinds of coal in Colorado

section of coal-bearing rocks in Oklahoma coal field

Virginia coal field

Gas pool coincident with a

31. Hypothetical cross-section through a volcanic neck in the oil fields of

Vera Cruz and Tamaulipas, Mexico

32. Hypothetical section in same district as Fig. 31

of Wyoming, showing approximately the areas underlain by

42. Section across portion of oil district of southwestern

showing cleavage and bedding in slate

58. Section in slate

Mexico oil field

through the Vlightberg, showing position of natural

63. Geologic sections

cement quarries at Utica, 111

70. Figures representing the origin of

showing number and thickness of

New York state

73. Section across Hoist on