THE FOSSIL FIELDS OF WYOMING 



Jurassic (Continued) — 



5. Fine ash-colored marls with thin beds of light 



colored cherty limestone. 



6. Gray and orange-colored marls with intercala- 



tions of coarse sandy layers. 



7. Reddish yellow sandstone. 



Triassic — 



8. Brick-red compact sandstone, Tnassic. 



Como Lake occupies an anticlinal valley. 

 In the marls both above and below the sandstone, a little 

 above the middle of the series, are Jurassic fossils, as Pentacrinus 



astericus, Belemnites densus, Tancredia Warrenana, Trigonia 

 quadrangularis. 



The Trias is included in the belt of conformable strata 

 wrapped around Elk Mountain, with Carboniferous beneath 

 and Jurassic above. 



The west side of Rawlins quaquaversal uplift is marked by 

 concentric monoclinal ridges, the Trias showing above 700 

 feet thickness, with pink sandstone at base and deep red above. 



Clarence King further says that nearly up to the 41st 

 parallel the red beds lie directly on the Archean from 300 to 

 800 feet thickness. They are also often seen resting conform- 

 ably on the Paleozoic. 



"The Trias is essentially sandstone and includes both clays 

 and shales, and is of a prevailing brick red color. Next to 

 color the most noticeable feature is cross-bedding, which is 

 marked in the upper beds, but not seen near contact with the 

 Archean. Conglomerate zones appear in the lower part. 

 No organic remains have been found, but a few obscure pieces 

 of half-petrified and half-carbonized wood. 



"On the east side of the valley of Laramie River, near the 

 Wyoming and Colorado line, are seen 1 ,200 feet of beds dipping 

 slightly north and west, and presenting a high, abrupt wall of 



—38— 



