1915] 



Clark: Fauna of the San Pablo Group 



483 



the subtabulation is strongest on the body whorl ; base of body whorl 

 flattish, the whorl being angulate at the juncture of the sides with 

 base. First whorl of spire sculptured by five equally spaced, fairly 

 prominent, narrow spiral ribs, the interspaces between which are 

 about twice as wide as the ribs; besides the major spiral sculpturing 

 finer spiral lines may be seen with the aid of a lens, covering both the 

 major ribs and the interspaces. The major spiral ribbing on the sides 

 of the body whorl is crossed by fifteen or sixteen obliquely sloping, 

 fairly heavy, longitudinal ribs ; this longitudinal ribbing is more promi- 

 nent toward the anterior part of the body whorl but becomes less dis- 

 tinct posteriorly and is not visible on the whorls of the spire. The flat 

 base of the body whorl is covered by fine spiral ribs with very narrow 

 interspaces. Around the edge of the open umbilicus there is a narrow 

 area which is smooth. Aperture subquadrate ; umbilicus open, fairly 

 broad. 



On a smaller specimen of what appears to be undoubtedly the same 

 species and found at the same locality, there is no longitudinal ribbing 

 visible on the body whorl ; the spiral ribbing is similar to that seen 

 on the first whorl of the spire of the type specimen; on the base, be- 

 sides the finer sculpturing, there are two heavier ribs close to the 

 umbilicus. 



Dimensions. — Height, about 9 mm. ; greatest diameter of body 

 whorl, 13 mm. 



Occurrence. — Found in the San Pablo Group about one mile south 

 of the town of Danville, on the north side of Las Trampas Ridge, Uni- 

 versity of California locality, no. 323. 



TEGULA (CHLOEOSTOMA) NASHI, n. sp. 

 Plate 65, figures 6 and 7 

 Shell conical, fairly heavy; whorls five; body whorl slightly 

 broader than the height of the shell ; sutures strongly impressed ; sur- 

 face of whorls slightly convex ; body whorl angulate between sides and 

 base. Base flattened with a broad, deep, spiral groove situated about 

 half way between the angulation and the umbilicus. On the body 

 whorl just above the angulation there are two prominent spiral ribs ; 

 on each whorl of the spire, only one spiral rib is visible and this is 

 situated just above the suture. Extending- from the suture to the 

 posterior spiral rib of the basal whorl are about twelve oblique longi- 

 tudinal ribs ; this longitudinal ribbing is also present on the last whorl 



