1915] 



Clark: Fauna of the San Pablo Group 



471 



482 and 125. Also found in the Santa Margarita to the north of 

 Coalinga, where it is also associated with Astrodapsis whitneyi. 



PETKICOLA BUWALDI, n.sp. 

 Plate 60, figure 6 



Shell subquadrate ; beak low and inconspicuous ; hinge line, includ- 

 ing the anterior and posterior dorsal edges, nearly straight. Pos- 

 terior dorsal edge nearly twice as long as anterior dorsal edge ; an- 

 terior end broadly rounded, sloping nearly at right angles to the ven- 

 tral and anterior dorsal edges ; posterior end regularly and broadly 

 rounded ; ventral edge very gently arcuate. Surface sculptured by 

 broad, flat-topped, somewhat obscure, radiating ribs with narrow inter- 

 spaces. Two cardinals in left valve, the posterior cardinal being 

 slightly bifid. External ligamental groove short ; anterior to this and 

 not sharply separated from it is a rather broad, elongate, triangular- 

 shaped resilifer. 



Named in honor of Dr. John P. Buwalda. 



Dimensions. — Length, 29 mm. ; height, 25 mm. ; diameter, 9 mm. 



Occurrence. — A single specimen of a left valve was found in the 

 Upper San Pablo Group to the southeast of the town of Walnut Creek, 

 University of California locality 1942. 



TELLINA? DIABLOENSIS, n.sp. 

 Plate 61, figure 5 



Shell subtrigonal to quadrate in outline, subrostrate posteriorly, 

 more ventricose posteriorly than anteriorly. Beak inconspicuous, pos- 

 terior to center. Anterior dorsal edge very gently curved ; posterior 

 dorsal edge straight; ventral edge regularly rounded, rather convex; 

 posterior end bluntly pointed ; anterior end broadly and evenly 

 rounded. Surface covered by fairly prominent irregular incremental 

 lines, depressed along the posterior dorsal margin but with no well 

 defined line marking the anterior edge of depression. Ligamental 

 groove short ; hinge plate fairly heavy, with well-developed nymph, 

 resembling that on a Sanguinolaria ; one prominent bifid posterior 

 cardinal tooth ; anterior cardinal either obsolete or broken. Anterior 

 to the beak there is an elongate lateral tooth ; the distance between 



