MOLLUSKS FROM THE ASPEN SHALE (CRETACEOUS) 

 OF SOUTHWESTERN WYOMING 



By John B. Reeside, jr., 



Of the U. S. Geological Si^rvey, Washington, D. G. 



and 



A. Allen Weymouth, 



Of the California Company, Denver, Colo. 



INTRODUCTION 



The Aspen shale of southwestern Wyoming has yielded few 

 fossils except the abundant fish remains noted by everyone who has 

 dealt with the formation, consequently a collection containing am- 

 monites and a variety of pelecypods is worthy of special recorci 

 in spite of the fact that their state of preservation leaves much to 

 be desired. This material was secured by Mr. Weymouth during the 

 course of field work for the California Co., and is derived from 

 two localities on the Meridian anticline southeast of Kemmerer, 

 Wyo. Interesting features of the collection are that it contains the 

 genus Aco7npsoceras, not previously described from North America; 

 the genus Epengonocerds.^ not previously described from the interior 

 province, though its presence at a distant locality has been noted ; ^ 

 and a third genus, here named Kanahiceras^ whose geographic range 

 is much extended over that shown by previous records. 



The photographs of specimens shown in the accompanjdng plates 

 were made by W. O. Hazard and the photographs were retouched 

 and the plates assembled by Miss Frances Wieser. 



THE ASPEN SHALE 



The Aspen shale of southwestern Wyoming was named in 1907 

 by Veatch," the typical locality being the exposures near old Aspen 



1 Stanton, T. W., unpublished data. 



^Veafcb, A. C, Geography and geology of a portion of southwestern Wyoming: U. S. 

 Geol. Survey Prof. Paper 56, p. 64, 1907. 



No. 2860.— Proceedings of U. S. National Museum. Vol. 78, Art. 17 

 23909—31 1 1 



