1915] 



Clark: Fauna of the San Pablo Group 



497 



Occurrence. — Found on San Pablo Bay in Scutella gabbii zone, 

 University of California localities 409 and 511, also at many other 

 localities, Mount Diablo, Las Trampas, etc. 



SIPHONALIA DANVILLENSIS, n. sp. 

 Plate 67, figure 6 



Shell fusiform; body whorl tumid; spire high; sutures impressed; 

 whorls angulated well above the middle and tabulate between the 

 angulation and suture ; the angulation is somewhat inconspicuous on 

 the body whorl but prominent on the first whorl of the spire. Surface 

 of whorls sculptured by seven prominent transverse flute-like ridges ; 

 on the body whorl these ridges are heavier toward the upper part of 

 the whorl, disappearing anteriorly. Shell also spirally sculptured by 

 fairly coarse, somewhat irregular ribbing, the interspaces between 

 which are very narrow. On the whorl of the spire there are ten of 

 these spiral ribs, three of which are on the tabulate area ; on the body 

 whorl there are thirteen spiral ribs, the ribbing being obsolete on the 

 tabulate area and on the canal. Outer lip sharp and thin ; inner lip 

 smooth, incrusted ; canal medium in length, very slightly turned back ; 

 umbilicus subperforate. 



Dimensions. — Height of body whorl, 25 mm. ; greatest width of 

 body whorl, 22 mm. 



Occurrence. — From the San Pablo Group to the south of Danville, 

 University of California locality 323. The writer has only one speci- 

 men of this species in his possession at the present time, and the upper 

 whorls of the spire of this have been broken off. 



TROPHON CARISAENSIS Anderson 

 Plate 66, figures 1 and 2 

 Chorus carisaensis Anderson, Calif. Acad. Sci., 3rd series, vol. II, no. 2, 

 p. 206, figs. 90-91. 



Trophon carisaensis Anderson Arnold, Bull. U. S. G. S. no. 396, pi. X, fig. 

 4; Bull. 398, pi. XXXII, ag. 4. 

 Shell rather large and thick, strongly spinose and oblique; spire moderately 

 high, sloping above; body whorl narrowing rapidly below; aperture large, tri- 

 angular, bearing a stout tooth on the outer lip near the upper end of the canal; 

 canal narrow, short and strongly recurved; columella crusted and strongly re- 

 curved; surface marked only by strong lines of growth. There are eight strong 

 spines on the angles of each whorl, excavated in front and convex behind. 



This species is quite variable. The characteristics that seem to be 

 the most constant are the heavy spines which stand out nearly at right 



