206 
PALAEONTOLOGY OF NEW-YORK. 
Fig. I a. A young specimen, with the shell partially exfoliated; a few of the septa being indistinctly 
visible. 
Fig. 1 b. A fragment, showing the shell in a considerable degree of preservation. 
Fig. 1 c. A portion of the surface of the last enlarged, showing the llexuous character of the striae. 
Fig. 1 d. A large specimen, preserving but indistinctly the striae. About twenty of the chambers are 
preserved, as well as a large part of the outer chamber. This specimen shows a small septate 
tube within the open extremity, but it is probably accidentally present. 
Position and locality. This species occurs in the higher part of the Trenton limestone at 
Middleville. 
17. 2. ORTHOCERAS LAQUEATUM, 
Pl. LVI. Figs. 2 a, b, c. 
Reference Plate iii, fig. 12 of this Report. 
Small, teretely conical, somewhat gradually tapering ; surface marked by sharp elevated 
longitudinal ridges, alternating with finer intermediate ones ; no transverse striee ; septa? 
siphuncle? section circular. 
This is evidently identical with the species fig. 12 of Plate III. In that specimen, there 
are no indications of the intermediate finer lines, which are indistinctly visible in the larger 
specimen fig. 2 a , while they are very distinct in the smaller one. I have been unable to 
find a specimen showing either septa or siphuncle. 
Fig. 2 a. A fragment imbedded in compact limestone. 
Fig. 2 b. A small fragment, showing the intermediate finer strise. 
Fig. 2 c. A portion of the surface enlarged. 
Position and locality. This species is comparatively rare in New-York, but still lias a 
wide geographical and somewhat extensive geological range ; the one figured on Plate III 
being found in the upper part of the Calciferous sandstone, while the specimen 2 a is found 
in the lower part of the Trenton limestone at Watertown. The smaller specimen is from 
the middle portion of the same rock at Middleville. 
272. 25. ORTHOCERAS LAQUEATUM ? var. a. 
Pl. LVI. Fig. 3. 
This specimen is marked by sharp longitudinal ridges, about equally distant with the 
stronger ones in the preceding figures, but having no intermediate ones. The surface is 
well preserved, and presents an aspect somewhat different from the preceding, and may 
perhaps prove a distinct species. 
Position and locality. In (he lower shaly strata of the Trenton limestone at Middleville. 
