CRETACEOUS FOSSILS. 177 



C. AL^EFORMIS, n. 8. 

 PL 29, Fig. 63. 



SHELL large, broadly rounded in advance, narrow, produced, 

 and truncated behind ; beaks about a third of the length from 

 the anterior end, high; posterior cardinal margin nearly straight, 

 bordered by a broad, deep groove, extending from the beaks to 

 the posterior end; base prominently and broadly rounded in the 

 middle, sinuous behind. Surface marked by small, regular, con 

 centric ribs. 



Figure, natural size. 



From a bed intermediate in age between the Martinez and Tejon Groups, near 

 Lower Lake village, Lake County. 



The largest of our Californian Corbulas, and characterized by its narrow pro 

 duced posterior end. 



ANATINA, Lam. 



A. QUADRATA, n. 8. 

 PL 29, Fig. 64. 



SHELL moderate in size, subquadrate; beaks nearly central; 

 length and width about as eight to five ; anterior end gaping, 

 truncated, and with the corners rounded ; posterior end convexly 

 subtruncated, or rounded; base nearly straight, being a very 

 slight curve, most prominent in the middle; the cardinal margin 

 is slightly excavated in advance of the beaks, and sloping and 

 nearly straight posteriorly. Surface marked by a few lines of 

 growth. 



Length, 2. inches ; width, 1.25 inch. 



From the greenish rock on the north shore of Departure Bay, Nanaimo, Van 

 couver Island ; associated with Pecten Traskii, Trigonia Evansana, and other 

 species characteristic of the Chico Group in California. 



O*f somewhat the style of A. lata, but longer and more regularly quadrate ; from 

 A. Tryoniana it can be distinguished by being shorter, the ends being more dis 

 tinctly truncated, and by its wanting the angular ridge descending from the beaks; 

 from A. inccquilateralis it can be known by the more central position of the beaks, 

 and the less rounded ends. 



PAL. VOL. II. 24 



