NO. 3 



GRAND CANYON FOSSIL FOOTPRINTS — GILMORE 



41 



only a few of the impressions show toe marks, and of the hind foot 

 none shows the full complement, all but one imprint lacking the fifth 

 toe. The sole is relatively narrow, elongate and obtusely rounded 



Fig. 17. — Bairachichnus obscurus. Type. No. 11,529, U. S. N. M. 

 Diagram of part of trackway. About f natural size. 



behind. Forefoot: Length about 5 mm., width 4.5 mm. Four digits. 

 First slightly set ofl' from the others and directed forward ana 

 inward, others extending almost straight forward. The forefeet im- 



FiG. 18. — Batrachichnus l>lai)ivillensis Woodworth. Genotype. Dia- 

 gram of trackway. Natural size. (After Woodworth.) 



])ressions are even more obscure than the hind, evidently due to the 

 fact that the tracks were made in very soft mud which, in most 

 instances, ran into the track as soon as the foot was withdrawn, 

 leaving only a slight depression. The contour of the palm is not fully 

 indicated in any of the tracks. 



