1914] Dickerson: Fauna of the Martinez Eocene of California 143 



number of spiral lines on the different body whorls is variable. Eight 

 were counted on the penultimate whorl, ten on the next and seven on 

 the eighth. Faint lines of growth cross the spiral lines. 



Dimensions. — Length, 32 mm. ; width of body whorl, 12 mm. 



Occurrence. — University of California Locality 1540, Trocho- 

 cyathus zitteli zone north of Mount Diablo. 



This species resembles T. martinezensis Gabb in its apical angle, 

 but the number of spiral lines is much greater than that of T. mar- 

 tinezensis. Its great apical angle is quite sufficient to distinguish 

 this form from all the other Eocene species of this genus. 



Named in honor of Mr. Bruce L. Clark, Instructor in Palaeon- 

 tology, University of California. 



CBRITHIUM, sp. 

 Plate 14, figure 2 



Shell robust, conical, with a large apical angle; about twelve flat- 

 sided whorls. These whorls are decorated by about twenty vertical 

 ribs, crossed by about ten revolving ribs. Of the two sets, the vertical 

 is the stronger. The body whorl has the short canal of this genus. 



Dimensions. — Length of broken specimen, 30 mm. ; width of body 

 whorl about 12 mm. 



Occurrence. — Abundant, but poorly preserved in the Martinez of 

 San Pedro Point, San Mateo County, California, University of Cali- 

 fornia Locality 692. 



ALARIA, sp. 

 Plate 14, figure 3 



Shell elongated ; spire high ; nine or ten whorls ; upper whorls 

 spinous, convex, widest a little below the middle; last whorl sharply 

 and acutely angulated, sloping and gently concave above and below 

 the angle ; suture impressed. Surface ornamented by fine, thread-like, 

 revolving lines, and by sinuous lines of growth. Canal long, narrow, 

 straight. Outer lip unicarinate, slightly curved. 



Dimensions. — Width of body whorl, 11 mm. ; approximate height 

 of spire, 12 mm. 



Occurrence. — University of California Locality 692. 



This species resembles Anchura angulata Gabb closely and it may 

 be identical with it, as Gabb's description was based upon a single 

 poorly preserved specimen found at Bull's Head Point. This form 

 may later be found to belong to the genus Spinigera. 



