TERTIARY FOSSILS. 51 



lated, sides flattened, upper surface sloping; suture distinct, im- 

 pressed. Surface ornamented by about a dozen small angular 

 nodes on the upper angle of the whorl, from which faint longi- 

 tudinal ribs descend over the body, becoming obsolete about the 

 middle; above similar ribs continue to near the suture; on the 

 earlier whorls these ribs are proportionately much larger; cross- 

 ing these are three or four elevated revolving striae above the 

 angle, and about twenty below ; these alternate pretty regularly 

 in size, eleven or twelve of them being large, the others much 

 smaller; lines of growth faint in the middle, more distinct 

 towards the two ends of the body volution. Aperture moderate 

 in size, broadest in the middle ; outer lip simple ; inner lip rather 

 heavily incrusted, bearing two strong, rather distant folds. 



Length, 2.3 inch ; width, 1.2 inch ; length of aperture, 1.3 inch ; width, .55 inch. 

 From the Pliocene of San Fernando Pass. Coll. by Mr. Frank Brown — a single 

 specimen. 



TROCHITA,. Schum. 



T. INORNATA, U. S. 



PI. 14, Fig. 8, 8a. 



Shell low, irregular, slightly oblique, nearly circular; volu- 

 tions about two to two and a half; suture linear, indistinct; surface 

 entirely without ornament, bearing only a few lines of growth; 

 margin of internal plate sinuous. 



Diameter, 1.1 inch; height, .G inch. 



From the Upper Miocene, near Half Moon Bay. 



ACM^EA, Esch. 

 A. rudis, n. s. 



PL 14, Fig. 9, 9c. 



Shell moderately large, subelliptical, outline slightly undu- 

 lated, not distinctly emarginate ; apex subcentral, prominent, 



