48-1 University of California Publications in Geology [Vol. 8 



of the spire but on the earlier whorls it becomes obsolete. Surface of 

 shell also covered by fine spiral lines, which pass over both the heavy 

 spiral and longitudinal ribs; on the base of the body whorl this finer 

 ribbing appears to extend only to the single spiral groove, the surface 

 being smooth, between the groove and the umbilicus. Aperture sub- 

 quadrate in outline; outer lip thin; umbilicus open; on the inner lip 

 there is a fairly strong tubercle. 



It is interesting to note that on the type specimen some of the 

 original color markings of the shell are preserved; on the base of the 

 whorl is a series of narrow, transverse, brownish stripes, radiating out- 

 ward from the umbilicus and extending obliquely onto the upper part 

 of the whorl in opposite direction to that of the longitudinal ribs. T. 

 nashi is closely allied to T. aureotinctum Forbes, a Recent species on 

 this coast, which is quite variable in outline. Most of the specimens of 

 T. aureotinctum show two heavy spiral ribs on the whorls of the spire 

 and on the base there are four fairly wide, deep grooves. The angula- 

 tion between the base and the sides of the body whorl is less distinct 

 on T. nash i ; otherwise the two species resemble each other very closely. 



Named in honor of Mrs. Louise Nash. 



Dimensions. — Height of shell, 14 mm. ; greatest width of body whorl, 

 16 mm. 



Occurrence. — Found in the Upper San Pablo Group east of the 

 town of Walnut Creek, University of California locality 1947. 



LITTOBINA PITTSBURGENSIS, n. sp. 

 Plate 65, figure 22 



Shell conical, thick ; whorls four to five in number ; sutures ap- 

 pressed. Body whorl rounding at base ; anteriorly the sides of the 

 whorls are slightly convex ; posteriorly they are slightly concave, giv- 

 ing a collar-like effect next to the suture. Surface smooth except for 

 lines of growth ; mouth nearly round. 



L. pittsburgensis, n. sp., is somewhat similar in outline to L. remondi 

 Gabb found in the Lower San Pablo of the same region, but it lacks 

 the angle at the base of body whorl and also the spiral ribbing which 

 is seen on Litterina remondi. The sides of the body whorl of L. remondi 

 are flatter than those of L. pittsburgensis. 



Dimensions — Height, about 13 mm. ; greatest width of body whorl, 

 10 mm. 



