170 PALEONTOLOGY OF CALIFORNIA. 



Length, 2.3 inches; width of body whorl, .95 inch; length of aperture, .55 inch. 



From beds intermediate between the Martinez and Tejon Groups, Martinez. 

 Numerous specimens were obtained at a single locality by Mr. Mathewson. 



This shell is entirely unlike any other Californian Cretaceous Turritella, and 

 resembles in its style of ornament some of the Eastern Miocene species. It can 

 be easily identified by its prominent single angle on each whorl of the spire, and 

 by its broadly expanding form, approaching in this character to T. robusta of the 

 Chico Group. 



NERITA, Linn. 

 S. Gen. Theliostyla, Morch. 



N. (T.) TRIANGULATA, D. 8. 

 PL 28, Fig. 52, 62 a. 



SHELL small, thick, semi-ovoid, spire flattened; whorls two or 

 two and a half, rapidly increasing in size. Surface divided by three 

 angles into four nearly equal revolving planes, each plane marked 

 by four or five rounded ribs with equal interspaces. Mouth 

 rounded subquadrate, outer lip subacute on the margin, very 

 thick behind, and internally toothed; inner lip broadly expanded, 

 nearly straight on its internal edge, and bearing a few large teeth, 

 its surface coarsely pustulated. 



Length, .28 inch ; width, ,38 inch ; height, .25 inch. 



Not common in the Tejon Group at New Idria, where I found but two speci 

 mens. It has never been encountered elsewhere. 



CALLIOSTOMA, Swains. 

 Zizyphinus, Gray. 



C. RADIATUM, n. 8. 

 PI. 28, Fig. 53. 



SHELL minute, broadly conical ; whorls four (or more), sides 

 flat, sloping ; suture well marked. Surface ornamented by four 

 teen or fifteen large radiating ribs, which produce an undulation 



