LOWER HELDERBERG ROCKS. 
345 
Ortlioceras clavatum (n. s.). 
Plate LXXI. Fig. 4. 
The specimen is a fragment, preserving a part of the outer chamber and several 
of the septa above. The form is somewhat abruptly tapering, and differs from any 
other species in the same group of strata. 
Geological position and locality. In the lower part of the pentamerus limestone : 
Schoharie. 
Ortlioceras -? 
Plate LXXI. Fig. 3. 
The specimen is marked by thin slightly convex septa; but having no others of 
similar character, it can scarcely be characterized. 
The condition of the Orthocerata in this group of strata is usually very unsatis¬ 
factory, all the species occurring in a fragmentary condition. 
Geological position and locality. In the pentamerus limestone : Schoharie. 
Ortlioceras teiiuiaiiiiulatimi (n. s.). 
Plate LXXII. Fig. 1. 
Shell cylindrical, very gradually tapering : septa unknown. 
Surface marked by thin abruptly elevated annulations, and by longitudi¬ 
nal striae, with obscure indications of fine transverse striae. 
Fig. 1. A fragment, natural size. 
Geological position and locality. In the shaly limestone of the Lower Helderberg 
group : Albany county. 
Ortlioceras Iielderliergise (n. s.). 
Plate LXXII. Fig. 2. 
Shell very gradually tapering; section circular. Septa distant about one- 
fourth the diameter of the shell; convexity of the septa nearly equal 
the space between them. Siphuncle small, central. Surface unknown. 
The specimen figured is compressed, and the lines of septa obscure. In another 
specimen, preserving a part of the outer chamber and fifteen of the succeeding 
chambers, the characteristic features are well preserved. 
Geological position and locality. In the shaly limestone of the Lower Helderberg 
group : Carlisle and Schoharie, Schoharie county. 
[ Palaeontology III.] 44 
