538 



NORTH AMERICAN INDEX FOSSILS. 



Beaks broad and prominent. 



Knoxville of California ; Queen Charlotte of Queen Charlotte 

 Islands. 



492. A. ovata (Meek and Hayden). Cretacic. 

 Transversely ovate. Beaks rather small and not much elevated. 



Surface marked with distinct growth lines. Length 2*^ inches ; 

 height nearly 2 inches. 



Montanan : North Dakota, Montana, Alberta, Assiniboia, Sas- 

 katchewan. 



CXXXVI. Veniella Stoliczka. 



Very similar to Arctica, but the left valve has the anterior car- 

 dinal teeth strong and subtriangular and there is present a more 

 or less pronounced posterior umbonal slope. Cretacic-Tertiary. 



493. V. conradi (Morton). (Fig. 735.) Cretacic. 



Fig. 735. Veniella conradi. (N. J. Pal., I.) 



Surface marked with several strong projecting growth lamellae 

 which do not extend across the posterior umbonal slope. A low 

 subangular ridge curves from the beak to the posterior extremity 

 of the hinge line. 

 Ripleyan of New Jersey (Merchantville-Tinton), Gulf region. 



494. V. trigona (Gabb). (Fig. 736.) Cretacic. 



FlG. 736. Veniella trigona Gabb. (N. J. Pal., I. 



