PEALE.] GEOLOGY WASHAKIE AND GREEN RIVER GROUPS. 



147 



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

 t.aceons. In a letter to me be says, " 1 have never seen any certain 

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

 'So. 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 TJ. S. Geol. Survey, 

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

 ent knowledge extends, only fresh-water aud 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." 

 " JBetween Black Butte and Bitter Creek stations (separated by a distance 

 of only six miles by a right line east and west) we observed uo marked 

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

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



13r. Haydeu (Report U. S. Geological Survey, 1867-'68-'69, p. 190) 

 says, " From Creston to Bitter Creek there is a series of j)urely fresh- 

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

 of fossils belonging to the genera fJmo, 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. 



^Ya1lsatcll group. 



Locality. 



Description of strata. 



Age. 



Authority. 



Reference. 



West of FortBridger. ! Variegated sands 



Tertiary 



Hayden 



Report U. S. Geol. 



and clays, some 







Survey, 1867-'68-'69, 



shade of red pre- 







p. 191. 



dominating; very 









little calcareons 









matter. 









West of Carter Sta- Ked, indurated, are- 



Beneath the Bridg- 



....do 



Report TJ. S. Geol. 



tion, and from! naceous clays, 'witli 



er group, and 





Survey, 1870, pp. 



Bridser Station to ' beds of grayish and 



probably s y n - 





147, 148. 



Aspen. 



reddish-gray sand- 

 stone alternating. 

 Pinkish and purp- 

 lish clays are the 

 dominant features. 



chronoua with 

 the Green River 

 group. 







Head of Echo Cafion. ' Reddish and purplish 



Miocene 



....do 



Do., p. 155. 





indurated sands 











and clavs. 









From Carter Station 



Variegated clays, 



Below Bridger 



....do 



Do., p. 168. 



to the middle of 



sands, and sand- 



gioup. 







Echo Canon. 



stones. 













On paleontological 

 grounds, synchro- 





Report TJ. S. Geol. 

 Survey, 1873, p. 441. 













nous with Green 





Also, Proceedings 







River epoch (Eo- 





Acad. Nat. Sci., 







cene). 





Phil., 1872, p. 279. 



Green River group. 



Locality. 



Description of strata. 



Age. 



Anthority. 



Reference. 



East of Rock Spring, 

 and in Green River 

 Valley (Green Riv- 

 er shales). 



K e a r Fort Stam- 



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. 



Hayden ... 



....do 



Report TJ. S G'ol. 

 Survey, 1867-'U&-'(,9, 

 pp. 190, 191. 



Report TJ. S. Geol. 

 Survey, 1870, pp. 

 39, 40, 



bangh, Sweetwater 

 Valley,BIa<;ls;'sFork 

 of Green River, Big 

 Sandy, and near 

 Granger Station. 







