288 REPORT OF THE AMERICAN COMMITTEE, 
excepting the Condylarthra, which probably occurs in both 
Bridger and Wasatch. 
This formation is known from one area, which is on the head- 
waters of the Wind River, near the Middle of Western Wyoming. 
The formation is, according to Hayden, not less than five thou- 
sand feet in thickness. 
Near the horizon of the Windriver beds must be placed the 
Green River Shales. This formation intervenes between the 
Wasatch and Bridger beds in Southwestern Wyoming, and differs 
entirely from both in lithological and paleontological characters. 
It consists of more or less finely-laminated calcareous or calcareo- 
siliceous shales, which have a depth of two thousand feet. The 
sedimentation has evidently been fine, indicating deep and still 
water. The Vertebrata obtained are almost exclusively fishes, 
two species of Crocodiles being the only exceptions. The fishes 
are clearly of Eocene character, and embrace some types (Gono- 
rhynchidre, Osteoglossidse, and Cichlidaa) now restricted to the 
Southern Hemisphere faunas. Two of these types, together 
with two other genera of fishes, occur in the Bridger beds ; and 
the two last named (Clastes and Pappichtlys) are also found in 
the Wasatch. A probable second locality of this formation is 
known in Eastern Utah, in the Wasatch Mountains. The forma- 
tion is known as the Manti beds. 
Bridger. — Mammalia, Presence of Tillodonta, ? Coudy- 
larthra, and Dinocerata, Hyrachyus, Paleeosyops, Amynodon, 
Triplopus, and Achsenodon. Absence of Teeniodonta, Panto- 
donta, and selenodont Artiodactyla. 
Two divisions of this formation are sustained by Scott. These 
have been named the Bridger and Washakie respectively by 
Hayden. The former is represented by a single area, which is 
west of Green River, in Southwestern Wyoming. The latter is 
also known from but one area, which is also in Southwestern 
Wyoming, but is east of Green River. These divisions differ in 
the species they contain, very few, according to Scott, being 
common to the two. Amynodon is the only genus which in the 
Bridger seems to be confined to the Washakie division ; perhaps 
Triplopus has the same distribution. 
Another tract of the Bridger formation is known from Western 
Colorado, but to which of the two above divisions it is referable 
is unknown. 
