COPE.] PALEONTOLOGY CRETACEOUS PERIOD ^AGE. 441 



of the two basics was marked during the Tertiary period, and hence 

 names the deposits of the western area the Wahsatch group, regarding 

 it at the same time as synchronous with those of the Green Eiver epoch. 

 The writer has attained the same opinion on paleontological grounds, 

 and has hence employed the same name for both areas, namely, the 

 Green River epoch.* 



As already stated,t the upper or red-banded Tertiary beds of this local- 

 ity yielded the following species : 



Perissodactyle bones, two species. 



Orotherium vasacciense. 



Crocodilus, sp. 



Alligator heterodon. 



Trionyjc scuttimantiquum. 



Emys testudineus. 

 gravis. 



Clastes (?) gldber. 



Unio, two species. 



The lower sandstone beds yielded the following mammals: 



Batlimodon radians. 



semicinctus. 



latipes. 

 Orotherium index.% 

 Fhenacodus primwvus. 



West of the contact of Bear Eiver with the Tertiary bluffs, the strata 

 consist of sandstone and conglomerates, and dip at about 30° to the 

 northeast. Five hundred feet vertically below the Bathmodon bed, a 

 stratum of impure limestone crops out, forming the slope and apex of a 

 portion of the bluff. In this I found the following vertebrates : 



Eeptiles : Trionyx scutumantiquum. Fishes : BMneastes calvus. 

 Emys f euthnetus. Clastes glaher. 



In comparing this list with that given for the lower beds of the Green 

 Eiver epoch, where they overlie the Bitter Creek coal, such resemblance 

 may be observed as is sufficient to indentify the two series. 



This is the nearest to a determination of the age of the Evanston 

 coal-bed, which Hayden regards as the most important west of the Mis- 

 souri Eiver, that I have been able to reach. From the limestone just 

 described to the coal-bed, two miles to the west, the strata are very sim- 

 ilar in character, and apparently conformable, so that they appear to be- 

 long to the same series. Dr. Hayden confesses hiiS inability to correlate 

 them with those of Bear Eiver City and Weber Eiver, but discovered 

 remains of plants which were identified with some of those known to 

 occur in the Fort Union beds, on the Laramie Plains, and the Upper 

 Missouri. If this be the case to a sufficient extent, the Evanston coal 

 must be referred to that division of the Cretaceous period. T.his con- 

 clusion is, however, only provisional, and Dr. Bannister's remarks* are 

 much to the point. He says, "In the upper beds northeast of Evans- 

 ton," (the ones I describe above,) " there seems to have been a consider- 

 able disturbance besides the mere tilting of the beds, and from the altered, 

 direction of the strike § we were led to suspect considerable lateral dis- 



* Proceedings Acad, of Nat. Sciences, 1872, p. 279. 



t Proceedings American Philosophical Society, 1872, p. 473. 



t Cope, Paleontological Bulletin, No. 17, 1873. 



$ Hayden's Annual Report, 1872, p. 541. 



