CONTRIBUTIONS TO PALEONTOLOGY. 47 



Surface concentrically striate, with a band upon the periphery. 



The specimens examined are almost entirely casts ; some remains only of 

 striae being preserved. The spire is less elevated than in the P. sulcomargi- 

 7iata, and the periphery and upper side of the last volution more rounded. 

 It is possible that these casts may prove identical with the preceding species 

 {P. rotalia); but no specimens with so great a diameter have been observed, 

 and the spire is more depressed than in that species. 



Geological formation and locality. In shales of the Hamilton group : 

 at Hamilton, Madison county ; and at Fultonham, Schoharie county, N.Y. 



CYCLONEMA HAMILTONIiE (n.s.). ^ ^V • ly 

 Shell subconical : height a little more than the width across the 

 last volution. Volutions four or five : apex minute and gradually 

 expanding to the body-whorl, which is somewhat abruptly ven- 

 tricose, flattened or a little concave for a short distance below the 

 suture, and the space limited on the lower side by a carina or the 

 first of a series of strong revolving striae. 

 Surface marked by fine lamellose lines of growth, which are di- 

 rected backwards from the suture without bending or curvature. 

 The volutions, except the narrow concave space above, are marked 

 by strong revolving striae or elevated carinate lines, of which 

 there are from fourteen to eighteen on the body-whorl. 



This species has nearly the proportions of Pleurotomaria lineata, except 

 in the more abrupt ventricosity of the body-volution. The concave belt on 

 the upper side of the volution, which is without revolving striaB and marked 

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

 of elevated concentric striae and the band upon the periphery. 



Geological formation and locality. In the shales of the Hamilton group : 

 Cazenovia, N.Y. 



CYCLONEMA LIRATA ( n. s.). ''^ j > I (^ 

 Shell robust, subdepressed-conical. Volutions about four, subangu- 

 lar, the last one becoming very ventricose : upper side of volu- 

 tions flattened from the suture to the first carinate elevation. 

 S^face marked by fine closely arranged striae of growth, which are 

 sometimes crowded in fasciculi giving gentle inequalities : these 

 striae are directed a little backwards from the suture. The volu- 

 tions are marked by moderately elevated carinate ridges, of which 

 1861.] 



