10 VEETEBRATA OF THE TERTIAEY. 



valley of Green River, particularly the regions between its atSuents both 

 north and south of the Uinta Mountains. In the Bridger Basin it forms a 

 ^Nnde rim around the Bridger formation, and is especially developed on 

 Fontiinelle Creek, and on Bitter Creek, and the region to the south of it. I 

 here found its thickness to be 1,200 feet.* Farther south, in Western Colo- 

 rado, near the Yampa River, Dr. "White gives its depth at 1,400 feetf 

 Farther south, in Western Colorado, Dr. A. C. PealeJ gives the united 

 thickness of this formation and the Wasatch at 7,670 feet; but how much of 

 this is to be refen-ed to the Green River proper we are not informed. It 

 does not appear to exist on the San Juan, according to Endlich and Holmes, 

 and I did not find it in New Mexico. 



According to King, the deposits of the Green River formation rest 

 un conformably on those of the Wasatch. § He also believes that it has a 

 considerable extent west of the Wasatch Mountains, over parts of Utah and 

 Nevada. Under the head of the Bridger formation I show that the paleon- 

 tological evidence is opposed to the identification of these "Amyzon" beds 

 with the Green River, and that they are probably of later origin. There 

 is, however, a series of calcareous and silico-calcareous beds in Central 

 Utah, in Sevier and San Pete Counties, which contain the remains of differ- 

 ent species of vertebrates from those which have been derived fi'om either 

 the Green River or Amyzon beds. These are Crocodilus sp., Clastes sp., and 

 a fish provisionally referred to Priscacara, under the name of P. testudinaria. 

 There is nothing to determine to which of the Eocenes this formation should 

 be referred, but it is tolerably ceiiain that it is to be distinguished from the 

 Amyzon beds. In its petrographic characters it is most like the Green 

 River. II 



The writer first refen-ed the Wasatch to the Eocene division of the 

 Tertiary, it having been previously regarded as Miocene. (Proceedings 

 American Philosophical Society, February, 1872.) 



The vertebrate fauna of the Wasatch is rich, and presents many pecu- 



• Annual H.port U. S. Gool. Snr\-., 18T3, pp. 436, 43!}. 



t Annual K.-port U. S. Gfol. Suit., 1870, p. 30. 



t Annual Ri-porl li^4, p. l."*. 



$U. S. SnrvfV of thr Foitipth Parallel, i, p. 377. 



II See American Naturnlist, April, lri@0. 



