424 University of California Publications in Geology [Vol. 13 



ASTAETE OVOIDES, n. sp. 

 Plate 30, figure 1 



Type specimen 12280, Coll. Invert. Palae., Univ. Calif., loc. 2157. 



Shell nearly circular in outline, slightly inequilateral; quite tumid at a 

 point about one-third the distance from the beak to the ventral margin; ante- 

 rior dorsal slope slightly concave but rapidly becoming convex and changing 

 into an evenly rounded anterior extremity; base regularly rounded, forming 

 with the anterior end an arc of a circle whose diameter is but slightly greater 

 than the height of the shell; posterior extremity curves abruptly from the base 

 toward the beak. Umbones very prominent; beaks sharply pointed, situated 

 anteriorly. Lunule present but imperfectly preserved. An indistinct flexure 

 extends from the posterior end toward the beak, becoming less conspicuous 

 dorsally. Surface sculptured by numerous evenly spaced concentric lines of 

 growth. Hinge and pallial line unknown. Adductor sears subequal, the anterior 

 being the more deeply impressed. Length of type, 28 mm.; height, 28 mm.; 

 convexity, 5.5 mm. 



Horizon. — Chico group, zonal position uncertain. 



ASTARTE (?) SULCATA, n. sp. 

 Plate 33, figure 6 

 Type specimen 12305, Coll. Invert. Palae., Univ. Calif., loc. 2141. 

 Shell very small, slightly quadrate in outline. Anterior and posterior dorsal 

 margins with similar slopes; posterior end slightly truncated; beaks small, 

 pointed, situated nearly central. Surface covered with a few heavy steplike 

 concentric ridges, which are about half as wide as the interspaces. Length of 

 type, 10 mm.; height, 7 mm.; convexity, about 2 mm. 



This small species is very abundant in the Actaeonella oviformis 

 zone. The type represents a rather small individual, some specimens 

 being 15 mm. in length. 



Horizon. — Chico group, Actaeonella oviformis and Turritella pes- 

 caderoensis zones. 



Family Cardiidae 

 Genus CARDIUM Linnaeus 

 CARDIUM COEONAENSIS, n. sp. 

 Plate 30, figure 2 

 Type specimen 12281, Coll. Invert. Palae., Univ. Calif., loc. 2130. 

 Shell small, nearly equilateral, as broad as high, subquadrate, ventricose; 

 anterior dorsal margin slightly convex, curving gently to the anterior extremity; 

 posterior dorsal margin nearly straight to a point beyond the hinge line, then 

 slopes very abruptly to the base of the shell; base arcuate. Umbones promi- 

 nent, tumid; beaks sharply pointed, adjacent; anterior dorsal area ill-defined. 

 A ridge extending from the beak to the anterior margin suggests that this 

 species belongs to the subgenus Protocardia. Inner margin entire. Surface 

 poorly preserved, but apparently devoid of sculpture. Length of type, 32 mm.; 

 height, 32 mm.; convexity, 24 mm. 



Horizon. — Chico group, Actaeonella oviformis zone. 



