344 
PALAEONTOLOGY OF NEW-YORK. 
PLATE LXXI. 
Fig. 1. A fragment of a large specimen preserving a part of the outer chamber, with about 
fourteen of the first chambers above. 
Fig. 5. A specimen showing a longitudinal section, apparently of the same species, the septa 
being proportionally a little more distant. 
Geological position and locality. In the pentamerus limestone of the Lower Hel- 
derberg group : Albany and Schoharie counties. 
Oitlioceras rigidum (n. s.). 
Plate LXX. Fig. 3 a - d. 
Shell elongate, gradually tapering; section circular. Septa moderately 
convex, distant from each other about one-sixth the diameter of the 
tube. Siphuncle central, narrow in its passage through the septum. 
Surface marked by fine sharply-elevated equal transverse striae. 
This fine species is only known in the fragment figured, which preserves more 
than forty of the septa. The surface striee are more finely and sharply marked than 
in any other species that has come under my observation. 
Fig. 3 a. A fragment of this species, having the shell almost entirely removed. 
Fig. 3 b. A continuation of the same specimen. 
Fig. 3 c. Transverse section, as shown in the line of fracture of fig. 3 b. 
Fig. 3 d. Enlargement of the striae. The position of the figure represents the striae in the 
reverse of their natural relation, which is horizontal. 
Geological position and locality. In the pentamerus limestone of the Lower Hel- 
derberg group : Herkimer county. 
Oitlioceras subtextile (n. s.). 
Plate LXXI. Fig. 2. 
Shell gradually tapering : siphuncle subcentral : septa unknown. 
Surface marked by strong transverse striae or low ridges, and by a much 
finer set of striae in the same direction, and the latter cancellated by 
a still finer set of longitudinal striae. 
A single fragment only of this species has been observed, but the peculiarity of 
the surface marking seems sufficient to distinguish it from any other species. 
Fig. 2. The specimen, natural size. 
Geological position and locality. In the lower part of the pentamerus limestone of 
the Lower Helderberg group : Schoharie. 
