CRETACEOUS FOSSILS. 203 



L. APPRESSA, D. 8. 

 PI. 31, Fig. 271. 



SHELL thin, flattened, elongated, irregularly oval ; anterior mar 

 gin straight, or very slightly convex ; posterior irregularly curved, 

 most prominent in the middle; ears unequal. Surface marked 

 near the base by a few faint, radiating undulations, crossed by 

 fine lines. 



Figure, natural size. 



Locality: San Luis Gonzaga Ranch (Division A.). A single cast retaining but 

 a small portion of the shell. 



PLICATULA, Lam. 



P. VARIATA, n. 8. 

 PI. 26, Fig. 190. 



SHELL variable, usually somewhat curved. Lower valve attached 

 by a portion of the surface, deep, radiately costate, ribs occa 

 sionally dichotomous. Upper valve flat or concave, plicate like 

 the lower, but not so strongly, the ribs being sometimes obsolete. 

 Hinge robust ; muscular scar large ; internal margin of the upper 

 valve crenate ; lower valve marked with pits corresponding with 

 the teeth above. 



Average length, about .7 inch. 



Locality: Abundant in a hard, gray, calcareous sandstone, from Battle Creek, 

 Shasta County (Division A.). 



This little shell is extremely variable in outline and convexity ; one of the com 

 monest forms is illustrated in the figure. 



ANOMIA, Linn., Mull. 



A. LINEATA, n. 8. 

 PI. 26, Fig. 193. 



SHELL thin, variable in shape; commonest form subcircular, 

 often obliquely truncated on the right side ; beak of upper valve 



