Geol.— Vol. II.] ANDERSON— STRATIGRAPHIC STUDY I95 



straight. The surface of the convex valve is marked only by concentric 

 lines of growth. The margin is more or less ragged or irregular. 



This species bears some resemblance to Ostrea sellaeforniis 

 Conrad, from the Eocene of Alabama. 



Occurrence. — This species is found only occasionally in the 

 Avenal Sands west and north of Coalinga. 



Miocene. 

 Cyrena (Corbicula) dumblei n. sp. 



Plate XIV, Figs. 30-32. 



Shell moderate in size, or large, 3 inches in greater diameter; sub-circular 

 in outline; beaks central, not greatly elevated, incurved; surface marked by 

 heavy and irregular concentric ridges, or smooth in young shells; teeth sharp 

 and prominent; lateral tooth long and slightly curved and finely crenulated. 



This species differs from C. californica Gabb in being 

 larger and more circular in outline and in having generally a 

 more robust form. 



Ocairrence. — This species is not rare in the lower Miocene 

 beds of Kern River. 



Venus (Chione) pertenuis Gabb. 



Venus pertenuis Gabb, Pal. Calif, v. 2, pp. 22 and 55, pi. v, fig. 37. 



In Gabb's description of this species there is some doubt 

 expressed as to its proper sub-generic determination, though 

 he says it very probably may prove to be a Chione. Several 

 specimens have been obtained from the Lower Miocene beds 

 of Kern River, some of them showing the hinge from which 

 Gabb's judgment is readily confirmed. 



Venus (Chione) conradiana n. sp. 



Plate XIV, Fig. 35. 



Shell large, rather thick, cordate, broadly rounded below, and much 

 produced behind; beak prominent, anterior, incurved; lunule large; surface 

 marked by concentric ridges, strongest in the umbonal region; margin thin 

 and not crenulated. 



