360 W. T. LEE UNCONFORMITY IN THE SO-CALLED LARAMIE 



plant remains similar to those in the overlying coal measures. The coal- 

 bearing rocks above the Trinidad sandstone are those that heretofore have 

 been called Laramie, but that are now known to constitute two forma- 

 tions. Since final correlations have not been made, it seems inadvisable 

 to use definite names for these formations; but, as shown later in this 

 paper, there are reasons for believing that the lower one may prove to be 

 older than Laramie and the upper one younger than Laramie. For this 

 reason the coal-bearing rocks above the unconformity will be provisionally 

 referred to as the post-Laramie coal measures and those below it as the 

 Cretaceous (Laramie or older) coal measures. 



Rock Formations in the Raton Field. 







Sandstone, conglomeratic, lithologically similar to 

 the Poison Canyon beds, and provisionally cor- 

 related with the Denver formation. 





* Post-Laramie (?) 

 1,200 feet. 



Sandstone below, conglomeratic at the base; coal- 

 bearing shale above. 



QQ 



Unconformity. 



o 



8 



* Laramie or older (?) 

 0-475 feet. 



Shale and sandstone, coal-bearing. 



Q 



Trinidad, 

 50-120 feet, 



Sandstone, shaly at base. 





Pierre, Niobrara, and 

 Benton, 8,000+ feet. 



Shale. 





Dakota, 200 ± feet. 



Sandstone. 



c^- 



Morrison, 300 ± feet. 



Shale and sandstone. 



02 



O 



Red beds, 10,000 ± feet. 



Red sandstone, coarsely conglomeratic, containing 

 boulders of the underlying crystalline and meta- 

 morphic rocks. 



c3 



o 



Pennsylvanian (?) 



Sandstone, shale, and limestone. 





Archean. 



Ancient igneous and metamorphic rocks. 



The Cretaceous coal measures consist of shales and sandstones having a 

 maximum measured thickness in Vermejo park of 475 feet, and lie appar- 

 ently with perfect conformity on the Trinidad sandstone. They thin rap- 



* Formerly called Laramie. 



