38 PALEONTOLOGY OF NEW YORK. 



only by lines of growth, is a distinguishing feature ; and also the absence of 

 elevated concentric striae and the band upon the periphery. 



Formations and locality. In the shales of the Hamilton group, Cazenovia, N. Y. 



Cyclonema obsoleta. 



PLATE XII, FIG. 87. 

 Cyclonema obsoleta, Hall. Illustrations of Devonian Fossils : Gasteropoda, pi. 12. 1876. 



Shell subglobose-conical. Volutions five or more in the entire condition, 

 becoming gradually expanded, and the last very ventricose ; the upper 

 volutions marked by fine revolving carinas, of which there are six or seven 

 on the volution above the last ; the carinas are distinctly crenulated by 

 revolving striae. The outer volution, so far as preserved, is marked only 

 by fine revolving striae. 



This species has the general aspect of the C. Hamiltonia, and may be only a 

 variety of that species, in which the carinaa have become obsolete on the outer 

 volution. The volution above the body-whorl shows six carinate lines, and 

 partially a seventh. There is a faint indication of the flattened band upon the 

 upper side of the last volution, which, in this specimen, is limited below by a 

 depression or line of fracture. 



Formation and locality. In sandstone of the Chemung group, from Southern 

 New York, — the particular locality unknown. 



Cyclonema concinna. 



PLATE XII, FIGS. 88-40. 

 Cyclonema concinna. Hall. Illustrations of Devonian Fossils : Gasteropoda, pi. 12. 1876. 



Shell subglobose below, conical above ; spire rapidly tapering ; volutions 

 gradually increasing in size to the last one, which is very ventricose. 



The figures are from gutta-percha impressions of the exterior mould left in 

 sandstone. The upper volutions present a double carina on the periphery like 



