572 Emery — Green River Desert Section, Utah. 



3. Sandstone and sandy shale, light brown below, 



greenish above, thin-bedded, some beds 1/16" 

 thick, with veins and interbedded layers of gyp- 

 sum 6" to 18" thick in middle portion 144' 



4. Sandstone, fine-grained, reddish brown on weathered 



surface, somewhat lighter on fresh fracture, lower 



part massive, upper part more thinly bedded . . . 127' 



5. Sandstone, massive, cross-bedded, red-brown to yel- 



low. Estimated 300' 



724' 

 The beds described above were included by Gilbert 21 

 in the "Flaming Gorge group" and have been referred 

 by Lupton 22 to the McElmo formation. Their lithologic 

 character and stratigraphic position are suggestive of 

 the Navajo sandstone of northeastern Arizona, and 

 accordingly all the beds in Green River Desert between 

 the Todilto (?) and the Salt Wash member of the 

 McElmo have been referred to that formation. The 

 limits of the Navajo as thus drawn are very definite in 

 Green Eiver Desert, but it is realized that the upper 

 limit here may differ somewhat from that on the Reser- 

 vation where Gregory states that the boundary l?etw r een 

 the Navajo and McElmo can not be too finely drawn. 23 

 That the contact in the two areas is not identical seems 

 likely for Gregory has included the beds of Theater 

 Rock in the McElmo while what appear to be similar beds 

 in Green River Desert are here referred to the Navajo. 

 Realizing that in northeastern Arizona there is appar- 

 ently no counterpart of the Salt Wash member of the 

 McElmo, which I believe indicates an unconformity, and 

 realizing that the contact of the Navajo and McElmo is 

 therefore uncertain in some degree, I have drawn the 

 boundary as sharply as possible in Green River Desert. 

 As so drawn, the Navajo contains all the red cross-bedded 

 sandstone and red sandy shale above the Todilto (?); 

 the McElmo includes light-colored coarse sandstone and 

 variegated shales entirely different in character from the 

 beds in the Navajo. 



McElmo Formation. (Cretaceous?) 

 The McElmo formation overlies the Navajo sandstone 

 and includes all the beds between it and the Dakota sand- 



- 1 Gilbert, G. K., op. cit., p. 6. 



22 Lupton, C. T., op. cit. 



23 Gregory, H. E., op. cit. 



