southwards

from WordNet (r) 3.0 (2006)

southwards
    adv 1: toward the south; "the ship turned southerly" [syn:
           {southerly}, {southward}, {southwards}]

from The Collaborative International Dictionary of English v.0.48

Southward \South"ward\ (?; colloq. ?), Southwards \South"wards\
   (?; colloq. ?), adv.
   Toward the south, or toward a point nearer the south than the
   east or west point; as, to go southward.
   [1913 Webster]