272 STANTON 



Apeibopsis discolor Lx. 

 Cissites lobato-crenata Lx. 

 Cissites tricuspidata Heer 

 Ficus planicostata Lx. 

 Ficus planicostata latifolia Lx. 

 Grewiopsis saportanea Lx. 

 Grewiopsis tenuifolia Lx. 

 Myrica torreyi Lx. 

 Ophegrapha antiqua Lx. 

 Pisonia racemosa Lx. 

 Podogonium atnericanum Lx. 

 Quercus viburnijolia Lx. 

 Rhamnus salicifolius Lx. 

 Sapindus caudatus Lx. 

 Sequoia acuminata Lx. 

 Smilax grandifolia Ung. 

 Viburnum marginatutn Lx. 

 Viburnum platanoides Lx. 

 Viburnum rotundifolium Lx. 

 Viburnum whyinperi Heer 

 Zizyphus fibrillosus Lx. 



The fresh-water element of the invertebrate fauna shows close 

 relationship by means of specific identity with the fauna of Hell Creek 

 and Converse County, while the brackish-water species are similarly 

 connected on the one hand with the Laramie fauna of Crow Creek, 

 Colorado, which is in the Denver Basin, and on the other with the 

 Mesaverde" fauna of Point of Rocks and other localities in southern 

 Wyoming and western Colorado. Of the fresh-water forms also 

 Tulotoma thompsoni ranges down into the Mesaverde and a few of 

 the Unios are represented by related species in that formation. 

 While this range removes such species from the list of distinctive 

 Laramie species it docs not impair their value as evidence of the 

 Cretaceous age of the beds where they are found. 



The fossil plants of Black Buttes also show some species in com- 

 mon with Converse County though according to Knowlton the rela- 

 tionship is not close. The flora is apparently more closely connected 

 with that of Point of Rocks, which is in the upper part of the Mesa- 



" In the current work of the Coal Division of the U. S. Geological Survey 

 the formation names used in western Colorado have been applied in southern 

 Wyoming. The Mesaverde corresponds in a general way with the combined 

 Eagle, Claggett, and Judith River formations of Montana and the Lewis 

 shale is the approximate equivalent of the Bcarpaw. 



