116 PALAEONTOLOGY OF CALIFORNIA. 



NISO, Risso. 



~N. POLITA, 11. S. 

 PI. 21, Fig. 113. 



Shell small, slender, conical; whorls many (about ten or 

 eleven ?), flattened on the sides ; upper edge minutely truncated. 

 Surface polished. Aperture imperfect in all the specimens. Um- 

 bilicus open, forming about a fifth of the lower surface. 



Figure, a little more than three times natural size. 



Locality: Four specimens from northeast of Martinez (in Division B.). 



CERITHIOPSIS, Forbes and Hanley. 



C. ALTERNATA, 11. S. 

 PL 21, Fig. 114, and 114 a. 



Shell long, slender; spire high; whorls about twelve or thir- 

 teen, convex; suture impressed. Surface marked by longitu- 

 dinal ribs, crossed by numerous revolving ribs, alternating, 

 pretty regularly, in size ; the larger ones form small tubercles 

 on crossing the longitudinal ribs, and occasionally, one of the 

 latter is larger than the rest, presenting the appearance of a 

 varix. Aperture broken ; columella strongly curved, and lightly 

 incrusted. 



Figures, natural size and magnified. 



Locality: Northeast of Martinez and Cochran's, east of Mount Diablo (Di- 

 vision B.) 



ARCHITECTONICA, Bolt. 



[Solarium, Lam.) 



A. Veatchii, n. s. 



PI. 19, Fig. 71. 



Shell small; spire high; whorls biangular, number unknown. 

 Surface marked by a number of small tubercular ribs; three on 



