i6 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 



6 9 



region east of the mountains yellow and pink sandstone, having a 

 maximum thickness of 150 feet, occurs between the Morrison and 

 the typical " Red Beds " at the horizon of the Sundance or near it, 

 and Butler, 1 suggests that it may belong to that formation. In view 

 of the relation of the La Plata sandstone to the marine beds as deter- 

 mined west of the mountains, it seems more probable that this sand- 



5 9 



Northwest Meeker 



Colorado (Gale) 

 Upper (Schultz) 



Cretaceous '■'•".: Dakota 



10 



Encampment 

 Wyoming 

 (Spencer) 



11 



12 



North Park Northeast 

 (Beekly) Colorado 

 ("Butler) 



Dakota 



Morrison 



Twin Creek 



White Cliff 



or 



Nugget 



Triassic 



610 

 1#f 



1000 



/ 



30/ 

 / 



WO 



1 

 BOO 1 



1 



1 



I 



1 



1 



1 



1 



Morrison 



Yellow ss. 

 /so 

 Pink ss. 



Lykins or 

 Chugwat or 



Fig. 3. — Group of columnar sections from northwestern Colorado to north- 

 eastern Colorado, showing the correlations of formations ranging in age from 

 Triassic to Upper Cretaceous. (For location of sections see fig. I, p. 11.) 



stone is equivalent to the unnamed sandstone of the Laramie Basin 

 section lying below the Sundance and to some part of the La Plata 

 sandstone. 



CENTRAL UTAH TO DENVER, COLORADO 



A series of sections from central Utah eastward to Denver, Colo., 

 shows relationships somewhat similar to those just described but 

 differing from them in some ways which are significant. The section 

 in Castle Valley differs from that near Greenriver only in the greater 



1 Butler, G. M., Colorado Geol. Survey Bull. 8, 1914. 



