:ws 
PALAEONTOLOGY OF NEW-YORK. 
Fig. 3 a. Yiew of the spire of a larger specimen : the last volutions are obscured. The 
surface preserves a few obscure wrinkles. 
Fig. 3 b. Aperture of the same. 
Fig. 4. The specimen is a partial cast, preserving a small portion of the shell, and showing 
very distinctly the volutions of the spire. 
Fig. 8. A cast of the same species. 
PLATE LVII. 
Fig. 4. A large individual which is extremely ventricose. The specimen is silicified, and the 
surface striae are obliterated. 
Fig. 2, Plate LXi, is possibly a specimen of this species. 
Geological position and locality. In tlie Slialy limestone, and in the compact layers 
of the same rock : Helderberg mountains, Schoharie, Catskill, Becraft’s mountain, 
etc. 
Platyceras gebliai'rii* 
Plate LYI. Fig. 5 a b, 6, 7 & 9 ; and Plate LV. Fig. Gab. 
Platyceras gebhardi : Conrad, Annual Report of 1840, p. 206. 
“ Differs from the last in having a much larger and more prominent 
“ spire, which is longitudinally carinated near the apex, and with distinct' 
“ transverse undulated strife.” 
Shell obliquely subovate or subglobose, somewhat gradually expanding, 
and becoming ventricose in the last volution. Spire composed of about 
four volutions, which are contiguous except the last one near the 
aperture, the apex being nearly in the plane of the outer volution : 
aperture expanded, campanulate, and sometimes with the lip reflexed. 
Surface marked by fine transverse undulating strife, which are sometimes 
distinctly bent backwards along a line near the dorso-lateral curvature 
of the shell, or nearer to the middle of the summit, and rarely slightly 
carinated along this line. In a few specimens, distinct revolving strife 
are seen cancellating the transverse strife. 
This species is distinguished from the last by expanding less rapidly, and being 
less ventricose; the apex of the spire never so far below the plane of the outer 
volution, being sometimes slightly below, on the same plane, or elevated a little 
above the outer volution : the suture line is deeply impressed, but not canaliculate. 
The carination mentioned by Mr. Conrad has been observed only in the specimen 
which he had under examination; though a similar bending backwards of the strife 
is noticed on other specimens, indicating a notch in the labrum, which appears to 
have been more conspicuous in the young shells than in the mature specimens. 
