SOUTH DAKOTA SCHOOL OF MINES 



139 



structurally among the present day Ceryidae is the musk 

 deer. The general proportion of the skull is much as in the 

 musk deer and like that animal it has no trace of horns or 

 antlers such as gradually developed in later times and the 

 upper canines are in the form of long, slender, recurved 

 tusks. The skeleton as a whole has many primitive char- 

 acters but the various species all show the general cervid 

 affinities. The animal in life stood from one to one and a 

 half feet high at the shoulders. 



Figure 72 — Skeleton of the primitive Lower Miocene deer, Blasto- 

 meryx advena. Matthew, 1908. 



REMAINS OF ANIMALS OTHER THAN MAMMALS 



As indicated elsewhere fossil remains of backboned 

 animals other than mammals in the Badlands are in genera] 

 of little numerical consequence. Only in the case of tur- 

 tles is there a decided exception. Occasional fragmentary 

 remains of lizards and crocodiles are found and a few petri- 

 fied birds eggs have been picked up but these are all that 

 are worthy of mention. Shelled animals lived in the region 

 but their remains are generally rare and of little conse- 

 quence except from the standpoint of refined science. The 

 beautiful and well known invertebrate shells from south- 

 western South Dakota so often seen in museums are from 

 older geological formations. Coming chiefly from the Chey- 

 enne river and its tributaries they are erroneously supposed 

 by many to be of the same age as the mammal-bearing beds 

 of the Tertiary. 



