280 PROCEEDINGS OF THE ACADEMY OF [Sept., 



NEW AND LITTLE KNOWN GASTROPODA FROM THE UPPER CRETACEOUS 



OF TENNESSEE. 



BY BRUCE WADE. 



An announcement of the discovery of unusually well preserved 

 Upper Cretaceous fossils in the Ripley formation on Coon Creek in 

 McNairy County, Tennessee, was made in the Contributions to 

 Geology of the March, 1917, number of the Johns Hopkins University 

 Circular. A somewhat detailed description of the locality and a few 

 preliminary observations on the fauna were made in the same article. 

 The studies of this fauna have since been pursued further and more 

 than 350 species have been recognized. 



The Gastropoda of this fauna are especially interesting, since this 

 class is so prolific and so well preserved. A systematic study of these 

 gastropods has recently been submitted as a dissertation from the 

 Geological Laboratory of the Johns Hopkins University. In this 

 study 151 species of Gastropoda from the Coon Creek locality have 

 been differentiated and described. As a result of the evidence 

 furnished by this large assemblage of perfect or nearly perfect univalve 

 shells, it has been found necessary, in order to classify all of these 

 forms, to propose several new generic groups. Descriptions of some 

 of the more interesting of these new genera and species have been 

 published recently^ and it is the purpose of the present paper to 

 present several additional forms of especial interest from this 

 locality.^ 



Family CONID^. 



Genus CONORBIS Swainson. 

 Conorbis mcnairyensis n. sp. PI. XVII, figs, l, 2. 



Description. — Shell very small and biconic in outline ; spire elevated, 

 its altitude equal to about half that of the entire shell ; whorls abruptly 



1 Published by permission of Dr. A. H. Purdue, State Geologist of Tennessee. 



2PROC. Acad. Nat. Sci., Phila., Julv, 1916, pp. 4.55-471, Pis. XXIII, XXIV. 

 Am. Jour. Sci. (IV), Vol. 43, pp. 293-297, figs. 1, 2, 1917. 



^ The writer wishes to express his indebtedness to Prof. W. B. Clark and his 

 associates in Paleontology, Prof. E. W. Berry and Dr. J. A. Gardner, under 

 whose guidance this study has been conducted. The writer is also indebted 

 to Drs. W. H. Dall, T. W. Stanton, L. W. Stephenson, C. W-. Cooke, and J. B. 

 Reeside, Jr., of the U. S. Geological Survey, and Dr. H. A. Pilsbry, of The 

 Academy of Natural Sciences of Philadelphia, for the privilege of studying their 

 collections, for the kindly interest they have shown in the work, and for their 

 assistance in helping to determine the biological relations of some of these forms. 



