52 



CENOZOIC MAM]VIAL HOBIZO^JS 



Trogosus {fAncMppodus Perissoda<'tyla-Equidje, Orohippxis: Car- 

 nivora, Ood^ctes, Vulpavus. 



2, Upper part of Bridger. levels C-D. rintathenum zone. Char- 

 acterized by presence of rintatTierium: PerissodactTla-Titanotheriidje, 

 Mesatirhinus megarliinus: Tillodontia, TiJloiheriurti; and lower beds, 

 or ZintaiJierium zone, of Uinta and Washakie basins, ?upper part 

 of Huerfano, Colorado. 



The fauna of these levels is very fully knowTi and the levels are 

 sharply distinguishable. 



The archaic fauna ^ includes mostlv mammals of larger size. As 

 in the Wind River, the Camivora-Creodonta include 3 families — 

 Oxyjenidje. Hyjenodontidae, and Mesonychidae — predaceous tyi>es 

 rapidly increasing in size and power. Aberrant Tillodontia, 2 

 genera (Trogosus, TUhthminn), their last appearance. Edentata- 

 Taeniodonta, 1 genus (Stglinodon), scarce animals, also their last 

 appearance. Of Ungulata-Amblvpoda. the Uintatheriidje or giant 

 Dinocerata suddenly appear in the upper Bridger, possibly from the 

 Great Plains Region. 



The modem fauna includes mammals of small and intermediate 

 size for the most part. The pro-Carnivora, Miacidae, rapidly multiply 

 and diversify into 8 genera, 20 species, analogous to the modem 

 Canid^e in tooth stmcture,*" and probably drive out the smaller 

 Camivora-Creodonta. Primates, 2-3 famihes, (a) Xotharctida?, 

 (6) Anaptomorpliida?, (c) f^licrosyopid^e. Rodentia more numerous 

 and diversified; the family relationships are uncertain, but include 

 (a) with sciuroid teeth, 2 genera; (h) with arctomyoid teeth, 3 

 genera. Insectivora more diversified. 4-6 famihes, including animals 

 analogous to if not actually related to Erinaceid^e, Talpidae, Soricidse, 

 Centetidae, also the aberrant Pantolestidae, ?Hyopsodontidje, and 

 fLeptictidje. Related to the Edentata-Dasyjioda, MetacJieiromys, 

 2 species. Ungulata-Perissodactyla flourishing, 5 families, namely: 

 (a) Equidae nimierous. 9 species: (h) Lophiodontidae, 3 genera: ic) 

 Tapirida?, 1 genus: {d) Titanotheriidae, 4 genera: first appearance 

 of the ie) Rhinocerotoidea-Hyracodontidae, 3 genera. Ungulata- 

 Artiodactyla still of small size, but chversified into 7 genera, includ- 

 ing primitive Selenodonta and Bunodonta. 



aAnchippodu-f: Leidy is typically from New Jersey, Shark River. Monmouth County. See Proc 

 Acad. Xat. Sd. Philadelphia, October, 186S, p 232. 

 f> See Appendix, p. 91. 



<■ Matthew observer, ks to the affinities of these animals: '"They do not make any approacfa to the 

 modem Canidse except for the dentition, which shows three groups — viverroid, cynoid, cerooleptoid. 

 The skeleton structure varies from cerooleptoid to viverroid. The skull structure in the viverroid 

 group is much more musteloid." 



