MOOK, STUDY OF THE MORRISON FORMATION 87 



Feet 



Sandstone, buff, fine-grained, evenlj- bedded and ripple-marked 6 



Clay, maroon and yellow, sandy 44 



Claj', dark brown to black, containing saurian vertebme, limb bones, and 



gastroliths 20 



Sand, gray, argillaceous, only locally indurated, containing wood silicified 

 in places, as well as rounded pebbles of similar material ; carbonized 



plant remains and small calcareous concretions 50 



Clay, maroon, sandy 55 



Sandstone, white, homogeneous, only locally indurated 25 



Clay, prevailingly gray and olive colored, but with three broad maroon 



bands, sandy 100 



Shale, green sandy, transitional to upper sandstone of the Sundance for- 

 mation 140 



580 



CENTRAL AND SOUTHERN WYOMING 



C. A. Fisher (1906, 4) describes the Morrison formation in the Absa- 

 roka and Owl Creek Mountain regions as follows : 



"Along the western side of the basin [Bighorn] the Morrison formation 

 is about 150 feet thick. It consists of alternating layers of gray fine- 

 grained sandstone and dark-gray sandy shale. Near the base there is 

 often a thin bed of gray limestone. In one locality near the southern 

 end of the Cedar Mountain anticline a deposit of gypsum 8 feet thick 

 was observed near the toj) of the formation." Fisher gives the follow- 

 ing sections : 



Section of Morrison Formation on Trail CreeJc, northwest of Cody, Wyoming 



Feet 

 Cloverly formation. 

 Green, sandy shales alternating with green clay containing thin layers of 



gray limestone throughout 100 



Massive, fine-grained gray sandstone lying on Sundance formation 30 



130 



Generalized Section of Morrison Formation south of Clark Fork Canyon, 



Wyoming 



Feet 

 Cloverly formation. 



Massive greenish-gray sandstone 80 



Greenish clay 60 



Dark gray limestone 1 



Dark gray sandy shale lying on Sundance formation 20 



161 



