CRETACEOUS FOSSILS. 177 



? L. CRETACEA, D. 8. 

 PI. 30, Fig. 255. 



SHELL thin, flattened, subquadrate ; beaks subcentral ; ends 

 and base broadly rounded, subtruncate. Surface marked only 

 by fine lines of growth. 



Figure, twice natural size. 



Localities: From Clayton to Marsh's, vicinity of Mount Diablo. 

 I have not seen the hinge of this little shell, and therefore refer it doubtfully 

 to the above genus. It is not rare at Marsh's, fifteen miles east of Mount Diablo. 



LORIPES, Poll. 

 ? L. DUBIA, n. s. 



PL 24, Fig. 170, and 171. 



SHELL subcircular, inflated; beaks moderately large, promi 

 nent, strongly incurved and inclined forwards ; margins regularly 

 convex; basal margin sometimes nearly straight. Surface, in 

 small specimens, marked by regular, concentric ribs, which, in 

 larger ones, become irregular and sometimes quite coarse. Margin 

 thin, not crenulated. Lunule apparently absent. 



Figures, natural size. 



Localities: Texas Flat, Placer County (Fig. 170); Chico Creek, Butte County 

 (Fig. 171) ; and Tuscan Springs, Tehama County (Division A.). 



This shell may prove to be the type of a new genus of Lucinidce. The hinge 

 resembles that of L. anatellinoides ; but the apparent absence of a lunule and some 

 other characters may serve to separate it from that species. The ligament appears 

 to have been decidedly external. Adams says: "No external ligament;" while 

 Chenu says: "Ligament Iog6 dans un sillon oblique du bord cardinal;" and his 

 figure of L. edentula shows it fully as external as it is in the present species. 



PAL. VOL. I. 23 



