GASTEROPODA OF THE LOWER GREEN MARLS. 123 
even this may be distinguished by the larger cavity left by the removal of 
the columella, and by the greater thickness or strength of the beak. The 
spiral ridges on this one are also more numerous and more sharply ele- 
rated, while the decided alternation of size among them will serve as a 
distinguishing feature. There is so great a similarity between this and 
many Tertiary forms of the genus that I shall not attempt to institute com- 
parison between them, as they would be useless as distinguishing features, 
and I know of no Cretaceous species resembling it. 
Formation and locality: In the marls of the Lower Beds at Holmdel, 
New Jersey. From Dr. Reiley’s collections. "The marl in which it occurs 
is of a ferruginous white color resembling some of the limestone nodules 
from the Lower Marls. 
NATICID. 
Genus NATICA Lamarck. 
NATICA ABYSSINA. 
Plate xv, Figs. 9-12. 
Natica abyssina Morton: Syn. Org. Rem. Cret., p. 49, Pl. xm, Fig. 13. 
Gyrodes abyssina (Mort.) Gabb: Synopsis, p. 59; Proc. Acad. Nat. Sci., Phila., 
1876, p. 295. 
Shell large, globose, with a flattened spire, the inner volutions of which 
scarcely rise above the outer ones, and are only two and a half to three in’ 
number; volutions rather ventricose and erect, ovate in a transverse sec- 
tion; umbilicus large and open to near the apex of the shell; aperture 
ovate, two-thirds as wide as long, and a little more convex on the outside 
than on the inner margin, nearly equally rounded above and below; suture 
well marked and deeply impressed. 
The species is represented only by casts in the New Jersey localities, 
so that the features of the surface are not known from within the State. 
Mr. Gabb cites it as coming from Patula Creek, Georgia, where, he says, the 
surface shell is preserved, but that it is perfectly plain. A single ‘ast which 
I have seen from New Jersey showed a deposit of ocher in the umbilicus 
which appeared to represent the thickness of the shell in that part. It was 
exceedingly thin and showed no callus or other feature of thickening. 
