The Tertiary Formations of the [March, 



Bear River, Wyoming (Hayden). 



Variegated r 



The Green River division of the Wasatch is much less exten- 

 sively distributed than the Wasatch proper. Its exposures are 

 confined to the valley of Green river, particularly the regions be- 

 tween its affluents both north and south of the Uinta mountains. 

 In the Bridger basin it forms a wide rim around the Bridger 

 formation, and is especially developed on Fontanelle creek and on 

 Bitter creek, and the region to the south of it. I here found its 

 thickness to be 1200 feet. 1 Farther south, in Western Colorado 

 near the Yampa river, Dr. White gives its depth at 1400 feet. 2 

 South of this, in Western Colorado, Dr. A. C. Peale 3 gives the 

 united thickness of this formation and the Wasatch at 7670 feet ; 

 but how much of this is to be referred 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 unconformably on those of the Wasatch. 4 He also believes 

 that it has a considerable extent west of the Wasatch mountains, 

 over parts of Utah and Nevada. I have shown that the 

 palaeontological 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 

 from either the Green River or Amyzon beds. These are Croco- 

 dilns sp., Clastes sp., and a fish provisionally referred to Priscacara 

 under the name of P. testudinaria. There is nothing to deter- 

 mine to which of the Eocenes this formations should be referred, 



Annual Report U. S. Geol. Surv., 1873, PP- 436. 437. 

 2 Annual Report U. S. Geol. Surv.. 1876, p. 36. 

 'Annual Report, 1874, p. 156. 



