MOOK, STUDY OF THE MORRISON FORMATION 



79 



coarse sandstone of moderate thickness. The sandstones are resistant to 

 erosion, md the beds dip steeply toward the west. The sandstones cap 

 ridges underlain by the softer clays, making a series of parallel or con- 



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Fig. 33. — Section of the McElmo formation near Green River, Utah. 



This section probably includes more than Morrison, as marine Jurassic fossils have been 



found in the base. Scale, 125 feet to 1 inch. (Lupton.) 



centric hog-backs, the outer one of which is capped by the "Dakota" sand- 

 stone. The contact of the marine and non-marine beds is obscure and 

 difficult to determine at the site of the Carnegie jMuseunfs quarry. 



