CENOzoic (interior). 289 
The depth of the Bridger proper is, according to King, two 
thousand five hundred feet. I have given that of the Washakie 
as about twelve hundred feet. 
DiPLACX)DON BEDS. — Presence of Mesonyx, Amynodon, Hy- 
rachyus, Triplopus, Epihippus, Diplacodou, Xiphodontidse (Pro- 
toreodon S. and O.), Poebrotheriidae (Leptotragulus), Eucrotaphus 
(Oreodontidse, S. and O.), and Adapidse (Hyopsodus Leidy). 
Absence of Amblypoda. 
The facies of this fauna is remarkably intermediate between 
the Bridijer below and the White River Miocene above. Genera 
found in the Bridger are Mesonyx, Araynodon, Triplopus. Hy- 
rachyus, and Hyopsodus. Families which commence here and 
extend upwards, are Menodontidae, Poebrotheriidse, and Oreodon- 
tidse. According to Scott and Osborn, Amblypoda are wanting and 
Creodonta are sparingly represented. The connection which this 
fauna establishes between those of the Bridger and the White 
River is complete, as has been shown by Scott and Osborn. 
One area is known. It is situated south of the Uinta Moun- 
tains in Northeastern Utah. The thickness of the beds is not 
great, according to King. 
This series was named by King the Uinta, but as that name 
had been previously used by Powell for a Devonian formation, 
I adopt the next oldest term, which was introduced by Marsh. 
Amyzon beds. — The exact horizon of this formation is not 
yet determined, but it is probably at the close of the Eocene or 
the opening of the Miocene. It is almost exclusively known 
paleontologically from fossil fishes, and these can be compared 
with those of the Green River shales. The characters are : 
Presence of Catostomidee, Siluridsa, and Trichophanes, Absence 
of Osteoglossidse, Gonorhynchidoe, and Chromididas. 
The only point of affinity with the Green River fauna is the 
presence of Trichophanes, which is nearly related to Aniphi- 
plaga of the latter. 
There are three widely-separated localities of this formation. 
One is in the South Park of the Rocky Mountains, Colorado ; 
another at Elko and Osino, in Northeastern Nevada; and the 
third is in Central Oregon, where it lies, according to Condon, 
immediately below the Johnday formation. 
Mutual Relations of the Eocene Formations. — Where 
the Bridger beds rest on the Wasatch, which I know to be the 
K 
