40 VERTEBRATA OF THE TERTIARY. 



Falunian. Loup Fork. 



Cosorijx. Cosoryx. 



Protolahis. 

 Procamelus. 



The existing genera mentioned as found in the Falunian fauna are 

 paralleled by the Dicotyles, Hystrix, and Mustela of the Loup Fork beds. 

 It is e\'ident that this latter horizon retains in its Oreodontidce the same 

 traces of antiquity that the Falunian does in its Ccenotherium, but shows a 

 more modem aspect in the omission of Anchitherium and its replacement by 

 Hippotherium and ProtoMppus, and in the still more modern type Hippidium. 

 Although but six genera of the two continents are determined as identical 

 in the above table, yet others, which are facing on the same line, are very 

 nearly allied. Other differences are geographical. The facies of the Loup 

 Fork horizon is then a compound of that of the Falunian and Oeningian, 

 or Middle and Upper Miocene. 



In commenting on the above-described fauna in 1874,* I remarked that 

 "the proper discrimination of the American Pliocene remains to be accom- 

 plished." It was not long after that date that material for making the 

 identification of this horizon on this continent first came into my hands. 

 This was derived from the superior Tertiary of Oregon, and includes a con- 

 siderable number of species of fishes, birds, and Mammalia. I published a 

 list of some of the species in 1878.t The character of the fauna from 

 that region coincides with that which has from time to time been unearthed 

 in the caves and other Eastern deposits, to such an extent, as to lead us to 

 suspect that the differences between them are geographical only. In Em*ope 

 the Pliocene, or Subapennine, includes, according to D'Orbigny (1855) and 

 Gaudry (1878), the Plaisancian and Astian, which are represented at the 



following localities : 



Subapennine. 



PlaUancian. — Montpellier; Casino (Tuscany). 



Antian. — Perrier, near Issoir, Ooiipet, Vialette (Upper Loire), Chagny; English 

 Orag; part of deposits of the Val il'Arno. 



Tlie characteristic of this fauna is the fact that the species belong 



• Report Lient. G. M. Wheeler, iv, Paleontology of New Mexico, 1874, p. 364. 

 fBuU. Hayden'8 U. 8. Geol. Snrv. Terra, iv, 187ti, p. 389. 



