COPE.] PALEONTOLOGY MIOCENE PERIOD. 461 



There are tbirty-eight or thirty-nine vertebrae, of which nine are ante- 

 rior to the first interneural spine, and fourteen between that point and 

 the first caudal vertebra. 



A very large number of specimens was obtained by Dr. Hayden and my- 

 self from the Tertiary shales of the Middle and South Parks, Colorado. 

 They display but insignificant variations in all respects, and furnish a good 

 basis of determination. They all differ from the A. mentale, Cope, (Proceed. 

 Amer. Philos. Soc, 1872, p. 481,) in the larger numbers of vertebrte and 

 dorsal and anal fin radii, and greater prolongation of the dorsal fin. It 

 is, however, nearly allied to the species of the Osino shales. The only 

 fish found associated with this one is the small nematognath just 

 described. The predominance of these types and exclusion of the 

 brackish-water genera Asineops, Urismatopterus, and Chipea, so abundant 

 in the shales of the Green Elver epoch, indicate a more lacustrine, and 

 hence, perhaps, though not necessarily, later deposit. 



CLUPEA, Linn. 

 Clupea theta, Cope, Bullet. U. S. Geol. Surv., No. 2, 1874, p. 51. 



Eepresented by a specimen from the Green Eiver shales, near the 

 mouth of Labarge Creek, in the upper valley of Green Eiver. It is a 

 larger species than the Ov pnsiUa, Leidy, which is also found at the same 

 locality, and has a much longer anal fin. Its radii number twenty-six, 

 possibly a few more, as the end appears to have been injured. The 

 dorsal fin is short ; the last ray in advance of the line of the first of the 

 anal. The body is deep. Number of vertebrse from the first interneural 

 spine to the last interhsemal, twenty-nine. Depth at first dorsal ray, 

 0.0485 5 depth at last anal ray, 0.0170 : length of twenty-nine vertebrae, 

 0.0780. 



CHAPTEE IV. 



THE MIOCENE PERIOD. 



The fauna of the White River epoch is well known to be entirely 

 distinct from that which preceded it, which is preserved in the beds of 

 the Bridger formation ; no species or genus of mammal is common to the 

 two, and but a proportion of the families. This difference is similar to 

 that which distinguishes the Lower Eocene from the Miocene fauna of 

 Europe. The parallelism of the Wyoming fauna with that of the 

 Eocene of France and Switzerland is very full, although not without 

 exceptions. Both are cliaracterized by the absence of equine peris- 

 sodactyles .and ruminant artiodactyles, of ElephanUdce^ Ehinoceridoe, 

 and extreme poverty in feline and musteline, or the higher carnivora- 

 Both are characterized by the presence of lemurs and generalized qua- 

 drumaua, and by the great predominance of Ferissodactyla allied to the 

 tai)irs. Parallel genera of the respective groups may be thus exhibited : 



"WYOMING. FEANCE. 



Carnivora, Mesonyx. Hycenodon. 



Quadrumana, Anaptomorplms, Adapts. 



Perissodactyla, Falwoayops. Falceotherium. 



Hyraahyus. Lophiodon. 



Hyopmdus. Hyracotherium. 



Artiodactyla, Achccnodon. Anthracotherium. 



