FOSSIL PLANTS FROM THE ASPEN SHALE OF SOUTH- 

 WESTERN WYOMING ^ 



By Roland W. Brown 



United States Geological Survey 



Until recently no fossils other than fish scales, lingulas, and bones - 

 have been reported from the Aspen shale of southwestern Wyoming. 

 In 1931, Reeside and Weymouth ^ described a number of ammonites 

 and pelecypods from this shale, but the first hint of the presence of 

 fossil plants in the Aspen was given in a personal communication, 

 May 17, 1930, by A. Allen Weymouth, of the California Company, 

 Denver. In the latter part of June, 1930, W. H. Bradley, of the 

 United States Geological Survey, and I visited the locality cited by 

 Mr. W^eymouth and made a good collection, which forms the basis for 

 this paper. 



The locality mentioned is northwest of Kemmerer, W^yo., in the 

 NW. 14 sec. G, T. 24 N., R. 115 W., in the low blulT on the south side 

 of the junction of Everly Creek and Fontanelle Creek and about 

 125 feet east of a north-south fence. The section of the Aspen shale 

 exposed in this region is about 1,000 feet thick. It shows strata of 

 black and gray shales, clay, thin coals, bentonite, gray sandstone, and 

 light-colored tuff, all dipping 35° westward. The gray to bluish- 

 gray shales weather into long rounded hills with a distinctive 

 greenish-graj' appearance. This was the only locality in the Aspen 

 at which we found fossil plants. 



The fossil plants occur in the uppermost 125 feet of the formation 

 in a thin stratum of bluish-gray hard mudstone, which is very brittle 

 and fractures conchoidalh^ The plants occur at all angles through 

 the matrix, making it someAvhat difficult to get entire specimens. 

 They are very well preserved and stand out black against tlie bluish- 

 gray background. 



The Aspen flora occurs in deposits which directly underlie the 

 Frontier formation of accepted Colorado age and are, therefore, 

 somev.hat earlier, but still Colorado in age. These two floras, there- 



1 Published by permission of the Director, U. S. Geological Survey. 



= Schultz, Alfred R., Geology and geography of a portion of Lincoln County, Wyo. U. S. 

 Gcol. Surv. Bull. 543, p. 59, 1914. 



3 Reeside, .John B., jr., and Weymouth, A. Allen, Mollusks from the Aspen shale 

 (Cretaceous) of southwestern Wyoming. Proc. TJ. S. Nat. Mus., vol. 78, art. 17, pp. 1-24, 

 liLs. 1-4, 1931. 



No. 2953.— Proceedings U. S. National Museum. Vol. 82, Art. 12 



150262—33 1 



