178 PALEONTOLOGY OF NEW JERSEY. 
mens are from the collection of the Acad. Nat. Sci., Phila., one of them being 
Dr. Morton’s type of the species. The green marl specimen is from Rutgers 
College, and was collected by Dr. Britton. 
PLEUROTOMARIID. 
Genus PLEUROTOMARIA Defrance. 
PLEUROTOMARIA ? TINTONENSIS, 0. Sp. 
Plate xxu, Figs. 6-9. 
Shell of about a medium size, discoid, the spire being but slightly 
elevated, only about one-half the height of the very depressed inner volu- 
tions projecting above the surface of the outer ones. Volutions about 
three in number, quite rapidly increasing in lateral dimensions from within 
outwardly, as broad again from the ventral to the dorsal margins as the 
height; surface depressed near the suture, convex nearer the outer margin, 
rounded on the periphery and flattened on the base for the outer half, 
while the inner half gradually slopes more rapidly to the sharp inner 
margin in the umbilicus. This latter feature presents a broad, open, fun- 
nel-shaped opening extending to the inner volution, and presenting scarcely 
any evidence of suture-lines between the whorls in the cast. The surface 
of the volutions is marked on the upper side by a row of broad, but 
low, rounded, dome-like elevations, increasing in breadth as the shell in- 
creases in size; fourteen of these elevations can be counted on the body 
whorl. The lower surface of the volution is angular at the junction of 
the base with the periphery, and the surface near or at the angulation 
marked by nodes similar to those above, but smaller and more numer- 
ous, and not extending so far from the outer margin. Just below the 
median line of the periphery there is a very slight ridge and angulation 
which indicates a very narrow slit in the lip of the shell of greater or 
less extent, allying it with the genus Plewrotomaria, although the general 
appearance is quite like that of Straparollus. Aperture transversely sub- 
ovate, widest at the outer third, angular at the outer basal portion, and 
rather acute at the inner angle. From the closeness of the suture-line 
in the cast, it would appear that the shell has been very thin. Surface 
of the shell unknown. 
