312 PAL2E0NT0L0GY OF NEW YORK. 



Orthoceras anguis, n. sp. 



II LTR I.XXXIX, FIG. 9. 



Shell straight, slender, regularly and gradually enlarging. Transverse section 

 unknown. The apical angle in a specimen much compressed is 5^°. 



Chamber of habitation, septa and siphuncle not observed. Air-chambers 

 regular, having a depth of four mm. near the chamber of habitation, where 

 the diameter of the tube is more than twenty mm. Sutures straight and 

 horizontal. 



Test not preserved. Surface marked by regular transverse, lamellose, 

 subimbricating striae, which become more crowded toward the apex, and of 

 which there are nine in the space of five mm., where the tube has a diameter 

 of about ten mm. Near the chamber of habitation the transverse lines 

 become elevated into irregular ridges, with very fine intermediate striae. 

 The internal mould retains the impression of the transverse markings. 



This species is distinguished from the associated forms by the marked 

 characters of the surface ornamentation. 0. aulax of the Hamilton, possessing 

 similar general characters, has the striae more rounded and distant. 



Formation and locality. From the shales of the Chemung group, Cascadilla 

 creek, Ithaca, N. Y. 



Orthoceras palmatum, n. sp. 



PLATE XC, FIGS. 9, 10. 



Shell straight, regularly and gradually enlarging. Transverse section subcir- 

 cular or very broadly elliptical. Apical angle about 7°. Initial extremity 

 unknown. 



Chamber of habitation not observed. Air-chambers regular, with a depth 

 of nine mm. where the tube has a diameter of thirty mm. 



Septa having a concavity equal to the depth of the chambers, with a distinct 

 areola around the insertion of the siphuncle, and a broad flabellate or palmate 

 expansion, extending to the ventral margin, which is indicated by a longitu- 



