26 
PALAEONTOLOGY OF NEW YORK. 
The fragment illustrated has portions of eight air-chambers and the base 
of the chamber of habitation, and measures nearly 160 mm. in length and 
67 mm, in diameter at the last air-chamber. 
This species somewhat resembles 0. Pelops (Pal. N. Y., vol. v, pt. 2, p. 233), 
but may be distinguished by the comparatively deeper air-chambers and more 
rapidly enlarging tube. 
Distribution. In the Schoharie grit, Clarksville, Albany county, 
Orthoceras sceptrum. 
PLATE CXVII, FIG. 2. 
Orthoceras sceptrum, Hall. Fifth Ann. Kept. State Geologist. Expl. pi. (117) 1, fig. 2. 1886. 
Shell large, straight along the outer chamber and slightly curved in the septate 
portion, regularly and gradually expanding to the base of the chamber of 
habitation. Transverse section sub-circular. Apical angle nine degrees. 
Initial extremity unknown. 
Chamber of habitation large, cylindrical, slightly contracting near the 
aperture; length about twice the diameter of the last septum. Air-chambers 
varying from 5 to 9 mm. in depth in the length of 140 mm., where the 
diameter of the tube is 40 and 55 mm. respectively. 
Septa thin. Sutures straight or somewhat curved, the degree of curva¬ 
ture being dependent on the amount of the weathering of the fillings of the 
air-chambers. The appearance of the septa and air-chambers indicates that 
there was an organic deposit in the apical portion of the specimen, but no 
distinctive characters can be discerned. 
Siphuncle sub-central. 
Test unknown. 
The individual described consists of the chamber of habitation and about 
thirty air-chambers, measuring 450 mm. in the entire length, of which 145 
mm. pertain to the chamber of habitation. The diameter of the tube near 
the aperture is 90 mm. and about 30 mm. at the distal extremity of the 
specimen. 
