498 



University of California Publications in Geology [Vol. 8 



angles to the sides of the whorls, and the deep fold on the body whorl 

 between the anterior end and the spines; the whorls of the spire on 

 some specimens show a distinct spiral ribbing-. The characters that 

 are the most variable are the prominency of the spines, the slope be- 

 tween the spines and the suture and the height of the spire. 



Occurrence. — Very common in the Upper San Pablo Group of San 

 Pablo Bay, north of Mount Diablo, Los Trampas and Rocky Ridges. 



TKOPHON GRACILIS Perry var. PABLOENSIS, n. var. 

 Plate 06, figures 6 and 7 

 Shell medium-sized ; spire rather high ; apex acute ; number of 

 whorls to spire five or six; body whorl large; sutures obscurely ap- 

 pressed. Whorls angulated, with the narrow surface above the angu- 

 lation sloping up gently to the suture. Surface of shell crossed by 

 ten or eleven prominent lamella-like varices which are flexed forward 

 and produced on the angle into upright, fairly prominent spines; on 

 the upper whorls of the spire the varices become prominent ridges. 

 Spiral ribbing lacking; outer lip sharp; inner lip smooth and in- 

 crusted ; canal broken on all the specimens that the writer so far has 

 obtained. 



This variety differs from the species T. gracilis Perry in being a 

 heavier and larger shell ; the tabulated effect above the angle is not 

 so marked; the suture is appressed while on T. gracilis it is depressed; 

 the lamella-like varices on the body whorl do not extend as far an- 

 teriorly as on T. gracilis and the spines at the line of angulation are 

 more prominent. 



Occurrence. — Found in the Lower San Pablo Group on San Pablo 

 Bay, University of California locality 409. 



TEOPHON DICKERSONI, n. sp. 

 Plate 68, figures 5 and 

 Shell medium in size ; spire one-third the height of the body whorl ; 

 sutures impressed; whorls regularly convex, except for a small tabu- 

 lated area just below the suture ; number of whorls five or six. Sur- 

 face covered by eight or nine lamelliform varices ; on the body whorl 

 the varices just below the suture and on the edge of the narrow tabu- 

 lated area form fairly prominent, broad, reflected spines. Surface of 

 shell also covered by two sets of alternating rounded revolving ribs, 

 one set being heavier than the other ; the interspaces between these ribs 



