38 
PALAEONTOLOGY 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. 37. 
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 carinae, of which there are six or seven 
on the volution above the last; the carinae 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. Hamiltonian , and may be only a 
variety of that species, in which the carinae 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. 38-40. 
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 
