260 PALAEONTOLOGY OF NEW YORK. 



This species has no allied form in the Schoharie grit, and is easily distin - 

 guished by its size, form, and the peculiarities of the chamber of habitation. 

 Formation and locality. In the Schoharie grit, Schoharie, N. Y. 



Section d. — Species having the cone longitudinally fluted. 

 Orthoceras Creon, n. sp. 



PLATE LXXIX, FIGS. H, 15. 



Shell small, straight, rapidly enlarging. Transverse section, allowing for the 

 degree of compression of the specimen, subcircular. Apex unknown. 



Only the base of the chamber of habitation has been preserved, which 

 presents no unusual features. Air-chambers regular, having a depth of 

 about two mm. 



Septa smooth, thin, having a concavity equal to an arc of about 100°. 

 The sutures, on a specimen somewhat compressed, are slightly curved and 

 oblique. 



Siphuncle small, subcentral. Its elements have been observed only at the 

 septa. 



Tube ornamented with regular furrows, formed by sharp, elevated, longi- 

 tudinal striae, of which there are four to five in the space of five mm. 



The only specimen of this species observed in the Schoharie grit has a 

 length of thirty mm., and preserves a portion of the outer chamber and four 

 of the air-chambers. A small fragment of the test from the Upper Helder- 

 berg limestone at West Avon, Genesee county, N. Y., and differing from O. 

 (Edipus and 0. profundum, appears to belong to this species. This fragment 

 shows the longitudinal striae to be cancellated by fine lines of growth, and 

 without the finer intermediate, longitudinal striae of O. Oedipus. 



This species, as occurring in the grit, may be distinguished from O. profundum 

 by its rapidly expanding tube, and finer surface ornaments. From 0. (Edipus 

 it is distinguished by its regular, sharp, longitudinal striae. 



Formation and locality. In the Schoharie grit at Schoharie, N. Y. 



