486 University of California Publications in Geology [Vol. 8 



Dimensions. — Maximum diameter, about 55 mm.; maximum alti- 

 tude, about 35 mm. 



Occurrence. — From the Lower San Pablo Group on the north side 

 and the south side of Mount Diablo, University of California localities 

 102, 480, etc. 



CALYPTEAEA MARTINI, n. sp. 

 Plate 70, figure 8 



Shell fairly large, coniform, somewhat variable as to height and 

 symmetry ; suture quite distinct, impressed. Surface covered by 

 medium coarse, flat-topped, radiating ribs ; on the body whorl there 

 are between thirty-five and forty of these ribs, between which the 

 interspaces are about as wide as the tops of the ribs. 



This species differs from C. diabloensis, n. sp., in that the ribs are 

 more numerous and are not so coarse and are wider apart. The rib- 

 bing is coarser than on C. filosa Gabb ; also, the shell is considerably 

 larger and the suture is more distinct. A comparison of C. martini 

 with C. costellata Conrad, figured by Arnold, from the lower Miocene, 

 shows that the ribs of the latter are less numerous, farther apart and 

 are rounded instead of being flat-topped. C. radians Lamark, a Recent 

 "West Coast species, differs from C. martini, n. sp., in having finer 

 radiating ribs, which also are not as flat-topped as in the latter, and 

 the sutures are not so distinct. 



Named in honor of Mr. Bruce Martin, formerly assistant curator of 

 palaeontology of the California Academy of Sciences, San Francisco. 



Dimensions. — Maximum diameter of type, about 43 mm. ; maximum 

 height, about 25 mm. 



Occurrence. — From the Upper San Pablo to the east of Walnut 

 Creek, Contra Costa County, University of California locality 1945. 

 Also from the uppermost fossiliferous beds in the Santa Margarita 

 to the north of Coalinga, University of California locality 2283. 



NATICA (EUSPIRA) DIABLOENSIS, n. sp. 

 Plate 68, figure 7 



Shell heavy, medium in size ; spire fairly well elevated ; number of 

 whorls five. Body whorl regularly convex, a little more than two- 

 thirds the height of the shell. Sutures appressed ; surface of shell 

 smooth, except for somewhat irregular incremental lines of growth. 



