128 PALEONTOLOGY OF NEW YORK. 



This is a strongly marked species, and readily distinguished from any other 

 at present known in these formations. It is extremely rare, since, up to the 

 present time, but two individuals are known. 



Formation and localities. In the shales of the lower part of the Chemung group 

 in Chemung county ; and near Ithaca, N. Y. 



The two species of Bellerophon, B. obsoletus and B. repertus, having been 

 omitted from the preceding descriptions, are inserted in this place. 



Bellerophon repertus, n. sp. 



PLATE XXVI, Flli. 9. 



Shell subglobose, rounded upon the dorsum, and regularly depressed into the 

 umbilicus. Transverse section of one volution subcircular. Body-whorl 

 ventricose and gradually expanding. Aperture apparently not expanding 

 beyond the regular enlargement of the body-whorl. 



Surface cancellated by fine, regular, revolving and transverse stria3. The 

 transverse striae curve slightly backward over the dorsum into the mesial 

 band. Dorsal band narrow, depressed, well-defined, and crossed by the 

 concentric stria? which form a distinct sinus. The species is distinguished 

 by its regular striate surface, and the narrow depressed mesial band. 



Formation and locality. Hamilton group, shore of Cayuga lake. 



Bellerophon obsoletus, n. sp. 



PLATE XXV, FIG. 15. 



Shell short, broadly subovate or globose, ventricose. Body-whorl regularly 

 expanding. 



Surface marked by obscure, lamellose, concentric stride, which make a broad 

 retral curve over the dorsum. The only specimen observed is imperfect, 

 and preserved as a natural mould in the rock. Its form and surface stria) 

 differ conspicuously from the other forms of the genus here indicated. 



Formation and locality. From the calcareous sandstone of the Chemung group 

 at Nichols, N. Y. 



