CRETACEOUS FOSSILS. 213 



lated and obliquely truncated below ; suture impressed. Surface 

 marked by numerous fine, revolving, thread-like lines, some- 

 times alternating in size, and on the angle near the lower margin 

 of the whorl, by coarse granulations. Aperture subquadrate. 



Figure, natural size. 



Locality: Near Martinez ; Mr. Mathewson ; very rare. 



SOLEN, Linn. 



Subgen. SOLEKA, Browne. 

 S. Diegoensis, n. s. 



PI. 32, Fig. 280. 



Shell thick, subconvex ; cardinal and basal margins nearly 

 parallel; beaks placed near the anterior end; ends gaping; 

 anterior end somewhat dilated ; base straight. Surface marked 

 by rather distinct lines of growth. 



Figure, natural size. 



Locality: San Diego ; very near if not at the top of the Cretaceous of the State; 

 collected by Mr. Morse. 



CHIONE, Miihlf. 



? C. ANGULATA, n. S. 

 PI. 32, Fig. 281. 



Shell small, thin, compressed, triangular; beaks small, acute, 

 prominent, placed about two-fifths of the length from the anterior 

 end, which is produced and narrowly rounded below, broadly 

 emarginate above ; the cardinal margin slopes nearly straight 

 from the beaks to the posterior end ; base broadly rounded. 

 Passing from the beaks to the posterior angle is a sharp ridge, 

 very near the margin ; posterior to which the surface drops at an 

 acute angle to the edge of the shell, making a well-marked, 



