238 PALJEOXTOLOGY OF NEW YORK. 



Orthoceras mascolum, n. sp. 



i'i.aii: i.xw in n, fig. 1. 



Shell large, straight. Transverse section circular. Tube very gradually 

 expanding. Initial extremity unknown. 



Chamber of habitation not observed. Depth of air-chambers varying 

 from ten to sixty -five mm.; their internal casts, in the specimen figured, 

 show a crenulated or tuberculated band at the anterior portion of each. 



Septa irregular, generally very distant, straight and horizontal ; concavity 

 unknown. 



Position of the siphuncle not determined. Test removed from all 

 observed .specimens. 



The internal mould is essentially smooth, with the exception of .the 

 crenulated bands above mentioned. The chamber walls are flat, with the 

 septal sutures but slightly impressed. The specimens are often covered 

 with numerous individuals of a species of Spirorbis. 



One fragment having a diameter of eighty mm., and containing four 

 air-chambers, measures 200 mm. in length. A similar specimen, with a 

 diameter of nearly 100 mm. and seven air-chambers, has a length of 220 

 mm. A smaller fragment with a diameter of the tube of sixty mm., and 

 possessing nearly four air-chambers, has a length of 180 mm. Several large 

 sections, referred to this species on account of their size, have a diameter of 

 from 105 to 125 mm. 



This species is remarkable for the large size and very gradual enlargement 

 of the tube, and the extreme variation in the depth of the chambers. These 

 characters distinguish this form from any associated species, or any species 

 now known in the Devonian period. 



Formation and localities. From the Schoharie grit, in the vicinity of Schoharie, 

 and near Clarksville, Albany county, N. Y. 



