Bake — Episodes in Rocky Mountain Orogeny. 249 



which there was a small local production. No identifiable 

 fossils, plant or animal, were found. 



These beds were mapped by Hague^- as Pierre and Fox 

 Hills, and are probably the same beds mentioned in one 

 paper by Hewett^^ as ^^ Tertiary sandstones and shales 

 probably of Wasatch age." At this point they were 

 probably not carefully examined by Hewett. Several 

 facts seem to favor the correlation of these beds with the 

 Fort Union of Hewett 's Shoshone River Section, rather 

 than with "Wasatch. 



The pebbles of these beds are significant. Hewett,^^ in 

 describing the Gebo, Meteetsee, and Ilo formations, men- 

 tions no conglomeratic material whatever. In the de- 

 scriptions of the equivalent Mesa Verde (Gebo), Meteet- 

 see, and Lance (Ho), Hewett and Lupton^^ similarly make 

 no mention whatever of pebbles, though both papers 

 describe the Fort Union as characteristically pebbly, and 

 both mention the occurrence of red granite, quartzite, and 

 Carboniferous cherts among the pebbles. This situation 

 would lead to the conclusion that the pebbly beds of the 

 present paper are far more likely to be the equivalent of 

 Fort Union than of older beds. 



Similarly neither of the reports cited describes red clay 

 in beds of Mesa Verde (Gebo), Meteetsee, or Lance (Ho) 

 age, though both mention its presence in the Fort Union, 

 a fact that would relate the red-clay-bearing pebbly sand- 

 stones to the Fort Union, rather than to older beds. 



The angular unconformity at the base of the pebbly 

 sandstones finds its counterpart in the angular uncon- 

 formity described by Hewett and Lupton^^ at the base of 

 the Fort Union, and tends to confirm the above conclu- 

 sions. The statement, also made by Hewett and Lupton, 

 that the Fort Union carries coal in the west side of the 

 Big Horn Basin, is further favorable to such a correla- 

 tion, especially in view of the fact that they report the 

 Wasatch non-coal-bearing in the Big Horn Basin. 



The considerably folded condition of these beds also 

 fits with the folding kno^vn in the Fort Union, while it is 



"Hague, Arnold; Absaroka Folio, U. S. Geol. Survey, Folio 52. 



" Hewett, D. F. ; Sulphur Deposits in Park County, Wyoming, U. S. Geol. 

 Survey, Bulletin 450, p. 478. 



"Hewett, D. F.; The Shoshone Eiver Section, U. S. Geol. Survey, Bul- 

 letin 541. 



^' Hewett, D. F., and Lupton, T. C. ; op. cit. pp. 26-28. 



^' Hewett, D. F., and Lupton, T. C. ; op. cit., p. 28. 



