PALEONTOLOGY OF NEW-YORK. 
Platyceras ctirvnostrum (n.s.). 
Plate LXY. Fig. 3 a, b. 
Shell with the spire gradually ascending : body - volution somewhat 
spirally trilobate, from two shallow depressions along the back of the 
shell, one on the upper and one on the lower side of the volution; the 
last volution free, and gradually expanding towards the aperture, which 
is subquadrate ; apex unknown. 
Surface marked by lamellose striae, which are strongly undulated in 
passing over the longitudinal depressions in the body-volution, and are 
more strongly marked towards the aperture. Obscure remains of lon¬ 
gitudinal striae are preserved on some parts of the shell. 
Fig. 8 a. The upper side of the spire, from which the surface is nearly all exfoliated. 
Fig. 3 b. The posterior side, showing the form of the aperture. 
Geological 'position and locality , In the upper pentamerus limestone : Schoharie 
county. 
Platyceras agreste (n.s.). 
Plate LXY. Fig. 4, 7. 
Shell with the body-volution somewhat arcuately ovoid : apex minute; 
the last volution spreading somewhat rapidly, rounded on the upper 
side and a little contracted below : aperture large, broadly oval ; 
peristome with a broad deep sinus on the anterior side. 
Surface marked by close transverse lamellose striae, which are crossed 
by finer longitudinal striae. 
Fig. 7. The lower side of the specimen, showing the aperture. 
Fig. 4 is a specimen having a similar form of the body-volution, but with the apex more 
acute. The shell on the upper part of the volution is marked by abruptly 
undulating longitudinal striae, and, near the base, the surface becomes roughly 
cancellated by the two sets of striae. 
Geological position and locality. In the upper pentamerus limestone : Carlisle, 
Schoharie county. 
