UiSDOUBTED TERTIARY SRECIES. 193 



roUnuKra, but it differs extremely in form from that type. I have tlierefore 

 proposed for its reception a new subgenus under the name Polyrhytis* 



I have seen but a single specimen of this shell, consisting of a well-defined 

 mould, from which a gutta-percha cast has been taken, and from this the 

 figures and description were prepared. The specific name is given in honor 

 of Clarence King, esq., the Geologist-in-charge of the Survey of the Fortieth 

 Parallel. 



Localitij and position. — Cache Valley, Utah; Tertiary, probably of 

 Miocene age. 



CERiniASIIDiE. 



Genus GONIOBASIS, Lea. 

 GoNiOBASis SiMPSONi, Meek. 



Plate 17, figs. 7,7 a, 7 b, 7 c, and 7 d. 



Melania Simpsoni, Meek (1860), Proceed. Acad. Nat. Sci. Pbilad., XII, 313. 

 Goniobasis ? ISimjysoni, Meek (18GG), ia Conrad's Soiithsoiiian Check-Li.st, 1'2 ; and (1876) 



in Col. Simpson's Report Expl. across the Great Basin of Utah, 365, pi. v, figs. 



1 « to 1 e. 



Shell attaining nearly a medium size, elongate-conical ; spire gradually 

 tapering apparently to an acute apex, which is not eroded ; volutions eight 

 or nine, flattened or more or less convex, increasing gradually and regu- 

 larly in size ; last one rounded below ; suture generally linear, and some- 

 times presenting a very slightly banded appearance, or becoming deeper as 

 the volutions assume a more convex outline. Surface ornamented with 

 more or less distinct, regular little vertical, or slightly arched costa;, which 

 are crossed by small, often obscure, revolving, raised lines, usually lai-gest 

 and most widely separated on the lower half of the body-volution ; costa?. 

 sometimes assuming a very faintly nodose appearance around the middle 

 of the volutions. Aperture rhombic-subovate, and a little oblique, slightly 

 sinuous at the base of the columella ; outer lip somewhat sinuous above, 

 and moderately prominent below. 



Length of a mature specimen, 0.78 inch; breadth, about 0.30 inch; 



* This subgenus bears the same relations to Limncva proper, that Gostella, Dall, 

 bears to the typical forms of riii/su. It was lirst proposed by the writer in the rahcout. 

 Upper Mo., 532, 1876. 

 13 PR 



