peale.] GEOLOGY WASHAKIE AND GREEN RIVER GROUPS. 



147 



As we have already seen, Cope considers the Bitter Creek series Cre- 

 taceous. In a letter to me he says, " I have never seen any certain 

 correlation of the Bitter Creek with the other lignite beds, so I call it 

 No. 6, with a question, although it may be a No. 7." Of the Washakie 

 group he says, " 1 have never studied the Washakie group, and do not 

 know where it comes in." Prof.F. B. Meek (Report U. S. Geol. Survey, 

 1872, p. 457) says, " In the latter (Washakie group), so far as our pres- 

 ent knowledge extends, only fresh-water and land types of fossils have 

 yet been found, and we have always regarded it as being of Tertiary 

 age. Exactly where the one ends aud the other begins we did not see." 

 u Between Black Butte and Bitter Creek stations (separated by a distance 

 of only six miles by a right line east and west) we observed no marked 

 change of litkological characters, from the Bitter Creek series to the 

 Washakie group, while the two series seemed to be conformable in dip." 



Dr. Hay den (Report U. S. Geological Survey, 1867-'68-'69, p. 190) 

 says, " From Creston to Bitter Creek there is a series of purely fresh- 

 water beds, with some beds of impure lignite, with vast quantities 

 of fossils belonging to the genera Unio, Melania, Vivipra, Helix, &c. 

 This group I regard as Middle Tertiary, and the strata are very nearly 

 horizontal. I have regarded these beds as separated from the Lower 

 Tertiary or true Lignite group, and have designated them by the name 

 of the " Washakie' group." The Washakie group, therefore, lies above 

 the Bitter Creek series. 



Wdhsatcli group. 



Locality. 



Description of strata. 



Age. 



Authority. 



Reference. 



West of Fort Bridger . 



West of Carter Sta- 

 tion, and from 

 Bridger Station to 

 Aspen. 



Variegated sands 

 and clays, some 

 shade of red pre- 

 dominating ; very 

 little calcareous 

 matter. 



Red, indurated, are- 

 naceous clays, with 

 beds of grayish and 

 reddish-gray sand- 

 stone alternating. 





Hayden 



....do 



Report TJ. S. Geol. 

 Survey, 1867-'68-'G9, 

 p. 191. 



Report TJ. S. Geol. 

 Survey, 1870, pp. 

 147, 148. 



Beneath the Bridg- 

 er group, and 

 probably syn- 

 chronous with 

 the Green River 





Pinkish and purp- 

 lish clays are the 

 dominant features. 



Reddish and purplish 

 indurated sands 

 and clays. 



Variegated clays, 

 sands, and sand- 

 stones. 

 • 



group. 



....do 



Do., p. 155. 



r 









From Carter Station 

 to the middle of 

 Echo Canon. 



Below Bridger 

 group. 



On paleontological 

 grounds, synchro- 

 nous with' Green 



* River epoch (Eo- 

 cene). 



....do 



Do., p. 168. 



Report TJ. S. Geol. 

 Survey, 1873, p. 441. 

 Also, Proceedings 

 Acad. Nat. Sci., 

 Phil., 1872, p. 279. 









Green River group. 



Locality. 



Description of strata. 



Authority. 



Reference. 



East of Rock Spring, 

 and in Green River 

 Valley (Green Riv- 

 er shales). 



X e a r Fort Stam- 

 baugh, Sweetwater 

 Valley, Black's Fork 

 of Green River, Big 

 Sandy, and near 

 Granger Station. 



Thinly laminated 

 chalky slates. 



Reddish or India- 

 ocher clays, with 

 leaden bands, yel- 

 low marls, and 

 rusty drab lime- 

 stones. 



Middle Tertiary, 

 above Washakie 

 group. 



Lower Miocene 



Hayden . 



.do 



Report TJ. S GpoI. 

 Survey, 1867-'G8-'G9, 

 pp. 190, 191. 



Report TJ. S. Geol. 

 Survey, 1610, pp. 

 39, 40.' 



