450 University of California Publications in Geology [Vol- 10 



CEETACEOUS SYSTEM 



Cloverly Formation. — The Cloverly formation is exposed only in 

 the center of the Gooseberry Creek fold where it has been cut across 

 by Gooseberry Creek. The formation here consists of reddish clays, 

 drab and buff sandy clays, thin buff clayey sandstones, a soft white 

 to gray, cross bedded, medium grained sandstone, and gray to lilac 

 limestone with thin lilac shale partings. At the top is a firmly 

 cemented, massive, ripple marked, somewhat cross bedded, fine to 

 medium grained, gray to brown colored sandstone that closely re- 

 sembles the Dakota and may be its equivalent. Stratigraphically it 

 occupies the position of the Dakota, being immediately below the dark 

 Benton shales. This resistant sandstone stands out sharply from the 

 soft shales both above and below it, and gives a crater-like form to 

 the crest of the fold (pi. 35 and 36a), and forms an almost vertical wall 

 on the east limb through which Gooseberry Creek has cut a narrow 

 notch as shown in plate 36b. 



The limestone is a dull gray to lilac gray, dense rock much veined 

 with ealcite. Small veins of opal up to one-sixteenth inch in width 

 are occasionally seen. Under the microscope the limestone is seen to 

 consist of very fine granular ealcite, the individual grains averaging 

 less than 0.01 mm. in diameter. This fine grained aggregate is occa- 

 sionally pink to red in color, probably due to finely divided red iron 

 oxide. Small grains of quartz up to 0.07 mm. are scattered through 

 the rock. No organic remains were present in the slide examined. 



Section op the Cloverly on Gooseberry Creek 



Thermopolis shale. feet 



Dakota(f) sandstone, hard, massive and ripple marked 55 



Reddish clays and buff sandy clays, thin sandstone layers '. 75 



Dense gray to lilac limestone with thin partings of lilac shale 5 



Red and buff clays and sandy clays 35 



Soft white to gray, medium grained, cross bedded, rather well washed quartz 



sandstone, the upper four or five feet thin bedded and calcareous 35 



Red, gray, and chocolate shales, buff sandy shales and thin sandstones, base 



not exposed ; 100 



Total 305 



The lower red shales, below the soft gray sandstone, may represent 

 the Morrison formation. However, as the authors have no definite 

 evidence as to this point, the lower shales are included in the Cloverly. 



Thermopolis Shale. — The name Thermopolis shale was first given 



