388 CRETACEOUS PALEONTOLOGY. 



field is also doubtless a member of the same species, although 

 its surface markings have been obliterated. The species differs 

 from N. eufauleims in the shorter anterior extension of the hinge- 

 line, and consequently in the more regularly rounded anterior 

 margin, in the more rounded umbonal ridge, and in the less 

 conspicuous sinus extending from the beak to the ventral mar- 

 gin. The two species also seem to differ in the character of their 

 surface markings. The general form of the shell more nearly 

 approaches N. hrevifrons, but the postero-basal extremity is less 

 extended, the surface markings are different and the anterior 

 hinge-teeth are straighter. 



Formation and locality. — Woodbury clay, Lorillard (102), 

 near Haddonfield (183). 



Geographic distribution. — New Jersey. 



Nemodon angulatum (Gabb). 

 Plate XXX., Fig. 15. 



i860. Leda angulata Gabb, Proc. Acad. Nat. Sci. Phil, (i860), 



p. 95, pi. 2, fig. 12. 

 1861. Leda subangulata Gabb, Synop. Moll. Cret. Form., p. 



189 (133). 

 1864. Nuculana subamgidata Meek. Check List Inv. Foss. N. 



A., Cret. and Jur., p. 8. 

 1868. Nuculana angulata Con., Cook's Geol. N. J., p. 725. 

 1876. Nemodon angulatum, Gabb, Proc. Acad. Nat. Sci. Phil. 



(1876), p. 31,6. 

 1886. Nemodon angulatum, Whiti., Pal. N. J., vol. i (Monog. 



U. S. G. S., vol. 9), p. 84, pi. 12, figs. 6^7. 

 1905. Nemodon angulatum Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 9. 



Description. — Shell small, the dimensions of the type speci- 

 men being: length, 15.5 mm.; height, 8 mm.; thickness, 5 mm. 

 Beaks rather prominent, situated at about the anterior third of 

 the shell. Anterior margin broadly curved from beneath the 

 beak to* the antero-basal region, where it curves more abruptly 

 into the nearly straight ventral margin, postero-basal margin 



