CRETACEOUS FOSSILS. 137 



covered between the genera Cri/pta on one side, and Trochita and 

 Galerus on the other. 



C. pileum, n. s. 



PL 29, Fig. 233, and 233 a, b. 



Shell deep, usually more or less oblique ; whorls about one 

 and a half, increasing very rapidly in size. Surface marked only 

 by very fine lines of growth. Margin of the internal plate concave 

 at the sides, convex in the middle, surface concave ; the upper or 

 right hand edge curved downwards abruptly, and uniting with 

 the side at an acute angle ; the posterior portion of the plate run- 

 ning up spirally into the apex. 



Figures, magnified. The largest specimen is about .6 inch in length. 

 Locality: Not uncommon near Fort Tejon, in Division B. 



NERITA, Linn. 



N". DEFORMIS, n. S. 

 PL 21, Fig. 96. 



Shell thick, robust, oblique; spire rather elevated; whorls 

 not distinguishable; body whorl flattened above, rounded on 

 the angle, pretty regularly convex below. Surface smooth, su- 

 tures obliterated. Aperture irregularly quadrate ; inner lip in- 

 crusted, not (?) crenulate. 



Figure, natural size. 



Locality: North fork of Cottonwood Creek (Division A.). 



This peculiar shell is the most irregular of all the species with which I am ac- 

 quainted in the genus. In fact, except its distorted outline, it has almost no* tan- 

 gible specific characters. 



N". CUNEATA, n. S. 

 PL 21, Fig. 97. 



Shell flattened, cuneate; outline elliptical, or sometimes nar- 

 rower atone end than the other; apex nearly terminal, blunt; 



PAL. VOL. I. — 18 



