354 GEOLOGICAL SUEVEY OF THE TEERITOEIES. 



1869 and 1870 ; from by Dr. collections made Carter from 1868 to 1871 ; 

 and from collections made by Dr. Joseph K. Corson, U. S. A., in 1871; 

 and Prof. O. C. Marsli, during the preceding year. 



Of the seventy-one vertebrated animals, for the most part clearly 

 characterized, thirty-four are mammals; one, a bird; twenty -five, reptiles; 

 and eleven, fishes. This assemblage of vertebrates presents no giants ; 

 but, on the contrary, they are nearly all comparatively small forms. 

 Among the mammals, the order of pachyderms presents species smaller 

 than any now in existence, and as small as any that have been found in 

 other formations elsewhere. 



The thirty-four mammals belong to twenty-two genera, all of which 

 are extinct except one, the genus Canis. The imperfect remains referred 

 to this may, on the discovery of more complete material, be found to 

 belong to another and perhaps an extinct genus. Sixteen of the twenty- 

 two genera are peculiar to the Wyoming Tertiary, or have not elsewhere 

 been discovered in other formations. Of the five previously known 

 genera, LopModon and LopMotherium belong to the early Tertiary forma- 

 tion of Europe ; Elotherium belongs to the middle Tertiary formation of 

 Dakota and of Europe ; Titanotherium belongs equally to the lowest 

 stratum of the Miocene Tertiary of the Mauvaises terres of Dakota ; and 

 Platygonus belongs to tbe Post-Pliocene formation of the United States. 



Of the genera of mammals, four belong to the carnivora, three to the 

 insectivora, three to the rodents, ten to the odd-toed pachyderms, and 

 two to the even-toed pachyderms. Primates, bats, solidungulates, pro- 

 boscidians, ruminants, marsupials, and edentates are not represented. 

 Seals, zeuglodonts, and cetaceans we do not look for in fresh- water 

 deposits. 



More than half the species of mammals — nineteen — appear to be i)eris- 

 sodactyles or odd-toed pachyderms, animals whose nearest living rela- 

 tives are the Tapir, the Hyrax, and the Rhinoceros. 



Strange is it that there is not a single ruminant among all the 

 mammals. These animals appear not to have formed members of the 

 ancient Tertiary fauna of Wyoming. Tapir-like pachyderms, small 

 Hyrax-like animals, rodents, insectivores, and carnivores appear to have 

 ; constituted the chief mammalian life. Euminants, solipeds, and pro- 

 boscidians appear to have come at a later period into existence, as 

 indicated by the Tertiary deposits of White Elver, Dakota, and the 

 Niobrara Eiver, Nebraska. 



A single owl and a stray feather tell us that ancient Wyoming had 

 its birds, but the paucity of material gives hardly a glimpse of the char- 

 acter of the class. 



Crocodiles were numerous in the early Tertiary period of Wyoming, 

 as indicated by their many remains. Six species have been named. 

 No traces of these animals have been discovered in the middle and 

 later Tertiary formations of White Eiver, Dakota, and Niobrara Eiver, 

 Nebraska. 



The land and waters of ancient Wyoming swarmed with turtles. The 

 Tertiary deposits of Dakota and Nebraska have yielded each but a sin- 

 gle species. The Tertiary deposits of Wyoming present us with abun- 

 dant evidences of the former existence of nine species. Of these one 

 was a Testudo or Land-Tortoise, as big as its modern representative of 

 the Gallipagos Islands. Two others belonged to the same genus, which 

 includes many of our living terrapenes, and one was a soft-shelled tur- 

 tle of the still-existing genns Trionyx. The other five turtles belong 

 to four peculiar genera, not noticed in other formations and times. 

 Several of them are related to our snappers, others to the terrapenes. 



