84 PALAEONTOLOGY OF CALIFORNIA. 



lines, which are somewhat enlarged on the crest of the ribs, form- 

 ing small tubercles. Two of these lines, just below the suture,, 

 form distinct ribs above the origin of the longitudinal ones. 



Figure, about two-fifths magnified. 



Locality : Tuscan Springs, Tehama County (Div. A.). Named after Mr. Averill, 

 one of the members of the Survey. 



F. Diaboli, n. s. 



PI. 18, Fig. 35. 



Shell elongated, fusiform, slender, spire acuminate, a little 

 longer than the aperture, sides flattened. Whorls seven, very 

 slightly convex. Aperture narrow; columellar lip apparently 

 incrusted by a very thin layer of enamel ; outer lip simple. Sur- 

 face marked by longitudinal ribs, about a dozen on the body 

 whorl; these ribs extend, on the last volution, for about half its 

 length, gradually blending into the surface. Across these are 

 numerous fine, impressed lines ; although in some of the speci- 

 mens they appear to be faint, or perhaps entirely absent. 



The figure is somewhat magnified. 



Locality: From the strata above the coal at Cochran's, east of Mount Diablo; 

 and some casts, probably of this species, from near Clayton, in the same position. 

 (All in Div. B.) 



F. ARATUS, II. S. 

 PL 28, Fig. 202. 



Shell robust, fusiform, spire rapidly tapering; whorls six, or 

 six and. a half, rounded on the side, abruptly truncated above, 

 and strongly channelled below the suture. Aperture rounded, 

 acute behind, columella not incrusted, anterior portion unknown. 

 Surface marked by lines of growth, and anteriorly by a few re- 

 volving lines. 



Figure, about two and a half times the natural size. 



Locality: A single specimen, marked, "near Martiiiez," in the collection of 

 Mr. Remond. 



