226 PALEONTOLOGY OF NEW JERSEY. 
between these two extremes. Considering that these variations occur in the 
shells, when the substance is preserved, among those recognized as of the 
same species, I conclude this may easily represent one of them, more 
especially as only a single individual has been seen for comparison. 
Formation and locality: In the upper layers of the Upper Green Mazrls, 
at Shark River, New Jersey. Collection at Rutgers College. 
NATICID. 
Genus NATICA Lamarck. 
NaTICA GLOBULELLA 0. sp. 
Plate xxxIv, Figs. 1-4. 
Shell small, not exceeding half an inch in its greatest diameter, and 
depressed globular in form, being somewhat broader than high, as seen in 
internal casts, with a moderately rounded spire; volutions rotund, with 
strongly marked sutures and apparently about four in number, only three 
to three and a half showing in the cast; umbilicus open and of moderate 
size, no evidence existing of a callus or thickened columellar lip; aperture 
semilunate, rounded below and apparently narrowly rounded above; sur- 
face destitute of markings, so far as can be detected on the casts, though 
the matrix has not been examined. 
This species, in its general form and proportions, resembles N. (Luna- 
tia) semilunata Lea, but the umbilicus appears to have been entirely open 
and too large for that species, and its form, as revealed by the casts, would 
not indicate it as a Lunatia. It is possible it may have been identical with 
some one of the several species of naticoid shells known from the Claiborne 
or lower beds of the southern Eocene, but as far as its characters are 
revealed, I should greatly doubt it. 
Formation and locality: In the upper layers of the Upper Green Marls 
at Shark River, New Jersey. In the collections at Rutgers College and 
Am. Mus. Nat. Hist. 
