16 



CONTRIBUTIONS TO PAL^ONTOLOGY 



EXPLANATION 



FiG. 6— Geological setting of Locality P. 374. After U. S. Geol. Survey Bull. 804, pl. 27. 



Section in the Lewis, Fox Hills, and Medicine Bow formations in the NE. j sec. 13, 



T. 21 N., R. 81 W., Wyo. 



Thickness 

 Medicine Bow f ormation (lower part) : in feet 



Sandstone, fine-grained, yellow-brown, massive 35 



Sandstone, gray, 2- to 4-foot beds and interbedded dark gray shales 64 



Sandstone, fine-grained, yellow-brown, massive 10 



Shale, soft, sandy; mostly covered 155 



Shale, gray, sandy, carbonaceous, and interbedded thin, gray, fine-grained sand- 



stones 28 



Shale, soft, sandy, thinly bedded, gray to brown, interbedded with thinly bedded 



gray, quartzitic sandstones 48 



Sandstone, massive gray-brown, fine-grained, cross-bedded near middle and at 



top, concretionary in upper third. Horizon 5 feet from base yielded the 



following fresh-water moUuscs : 



