39 



western area the Walisatch group, regarding it, at tiie same time, as synchro- 

 nous with those of the Green River epoch. The writer has attained the 

 same opinion on paleontological grounds, and has hence employed the same 

 name for botli areas, viz, the Green River epoch.' 



As ah-cady stated," the upper or red-banded Tertiary beds of this locality 

 yielded the following species : Perissodaetyle bones, two species ; Oroh/])pus 

 vasacciensis ; Crocodilus, sp. ; Alligator heterodon ; Trionyx scutumantiquum ; 

 Emys testudineus ; E. gravis ; Clastes glabcr ; Unio, two species. 



The lower sandstone-beds yielded the following mammals: BathmodoH 

 radians; B. semicinctus; B.latipes; Orohippus index ;^ Pkenacodus prinmvus. 



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

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

 Five hundred feet vertically lielow tlie 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: Reptiles : Trionyx scutumanliquum ; 

 Etwjs ? euthnetus ; Fishes: Rhineastcs calvus ; Clastes glaber. 



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

 River epoch, where they overlie the Bitter Creek coal, such resemblance may 

 be observed as is sufficient to identify 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 Missouri 

 River 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 similar in character, 

 and apparently conformable, so that they appear to belong to the same series. 

 Dr. Hayden confesses his inability to correlate them with those of Bear River 

 City and Weber River, but discovered remains of plants which were identi- 

 fied with some of those known to occur in the Fort Union beds on the Lara- 

 mie 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. This conclusion is, however, only provisional, and Dr. Bannister's 

 remarks* are much to tlie point. He says, of the upper beds northeast of 

 Evanston (the ones 1 describe above): "There seems to have been a consider- 

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



'Proceedings of the Acaileuiy of Nafnial Sciences, 1872, p. 279. 



'Proceedings of the Aiiicricaii Philosophical Society, 1872, p. 47.3. 



^ Cope, Paleontological Uiillctin, No. 17, 1873 ; also, The Extinct Vcrtcbrata of Now Mosico. 



■•Ilaydcii's Annual Report for 1872, p. 541. 



