MOLLUSCA. 635 



ruptly to the cardinal margins, the most gentle slope being to the 

 postero-basal extremity; a more or less obscure rounded or sub- 

 angular umbonal ridge passes from the beak obliquely backward 

 to the postero-basal extremity. Surface of the shell marked by 

 regular, fine, concentric lines, which become regularly stronger 

 in passing from the beak to the shell margin, and becoming nearly 

 obsolete upon the post-umbonal slope. 



Remarks. Gabb's type of this species has never been illus- 

 trated, but the New Jersey examples have been compared with the 

 original specimen and their specific identity can be safely assumed. 

 Veleda transverse, was described by Whitfield from "dark mica- 

 ceous clays below the Lower Marls at Marlborough," and the 

 horizon indicated can be no other than the summit of the Weno- 

 nah sand as seen near Marlboro. Whitfield's type specimen has 

 been compared with various specimens in the recent rollections 

 of the Survey, from the same horizon at a neighboring locality. 

 These show the characters of his species and demonstrate 

 its specific identity with Gabb's species from Georgia. The 

 specimens from the Cliffwood clay which have been referred to 

 the species, usually differ form the Wenonah sand examples in 

 their somewhat higher and more vertically truncated posterior 

 margin, these specimens also seem usually to have suffered a 

 greater degree of erosion of the shell, which has more or less 

 destroyed their surface markings. 



Formation and locality. Cliffwood clay, Cliffwood Point 

 (105), near Matawan (107); Wenonah sand, near Marlboro 

 (130), near Crawfords Corner (i26 3 ). 



Geographic distribution. New Jersey, Georgia, Texas. 



Genus RANGTA Desmoulins. 



Rangia ? tenuidens (Whitfield). 

 Plate LXXIIL, Figs. 6-8. 



1886. Gnathodon ? tenuidens Whitf., Pal. N. J., vol. i (Monog. 

 U. S. G. S., vol. 9), p. 27, pi. 2, figs. 7-10. 



Description. "Shell of moderate size, very ventricose, very 

 broadly ovate or subtriangular, with strong and rather tumid, 



