54 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



Cutting now walled up. A. C. L. Cretaceous shale," belongs 

 to this species. 



Named in honor of Dr. Andrew Cowper Lawson of the 

 University of California. 



Pholadomya subelongata Meek 



P. subelongata Meek, 1857; Tr. Alb. Inst., vol. 4, p. 42. 



P. brewerii Gabb, 1864: Pal. Cal.. vol. 1. p. 152, pi. 22, 

 fig. 123. 



P. rovana Whiteaves, 1879; Geol. Surv. Canada, vol. 1, pt. 

 2, p. 140. 



Shell ovate or subquadrate, compressed; beaks anterior, 

 moderate in size; posterior extremity rounded, sub-truncate; 

 posterior cardinal border nearly straight and gently sloping; 

 basal margin slightly convex. The anterior margin of the 

 left valve found is missing so the exact number of ribs can 

 not be told; 16 ribs can be counted, however, and there were 

 probably at least 25 which radiated from the beak and are 

 crossed by fine lines of growth. The ribs are obsolete near 

 the posterior cardinal margin. Locality 3, L. S. J. U. Pal. 

 Coll. 



Since Whiteaves has shown the wide variation in the num- 

 ber of ribs on P. royana and believes it to be the same as 

 P. subelongata, there seems no reason for retaining Gabb's 

 name, P. brewerii, as a different species. 



Pinna calamitoides Shumard 

 PI. 9, Fig. 4 



P. calamitoides Shumard, Trans. Ac. Sc. St. Louis, vol. 1, 

 p. 124, 1858. (From Vancouver Island.) 



P. calamitoides Shumard, Geol. Surv. Canada, vol. 1, pt. 

 2, p. 167, pi. 20, figs. 1. la, and lb, 1879. (From Sucia 

 Island.) 



P. brewerii Gabb. Pal. Cal, vol. 2, p. 195, pi. 32, fig. 93, 

 1869. (From the Chico of California.) 



Shell elongated, triangular, compressed, slightly curved; 

 angle of divergence of sides about 30° ; a strongly marked 

 rib near middle of valve, on one side of which are eleven 



