CONTRIBUTIONS TO PALAEONTOLOGY. G3 



This is a large species, frequently reaching the length of six inches. I am 

 indebted to Ledyard Lincklaen, esquire, of Cazenovia, for a specimen 

 five and a half inches inches in length, the upper end of which is truncated 

 by an arching septum ; and at this point, each face has a width of more 

 than half an inch. Had the shell been extended to an acute point in a line 

 continuous with the sides, it would have been more than seven inches in 

 length. 



The occurrence of a septum in the upper part of the cavity of Conularia 

 has been observed in specimens of at least three species from three diflferent 

 geological positions, and must be regarded either as a normal character of 

 the shell, or that the apex may have been deciduous as the animal receded 

 from that part of the shell, and this arrangement was adapted for its pro- 

 tection. 



Geological formation and locality. In the coarse shales of the Hamilton 

 group at Cazenovia, Hamilton and Schoharie, and in the Marcellus shale 

 near Bridgewater, Oneida county, N.Y. 



CEPHALOPODA. 



GENUS CLYMENIA(Munster). 



CLYMENIA COMPLANATA. 



Clymenia complanata : Hall, Geol. Report of the Fourth District New-Tork, 1843, 



p. 244, f. 5; p. 243. 



Shell discoid, flattened. Volutions four or five, slightly embracing, 

 gradually enlarging towards the aperture. 



Surface marked by fine regular striae, which are directed a little 

 forward from the ventral side of the volution, and, when near 

 the dorso-lateral margin, bend backward into a shallow revolving 

 groove, from which they make a very abrupt retral curve to the 

 dorso-lateral angle. Some remains of undulating septa are visible 

 in two specimens. 



This species, described from a compressed specimen in the green shale of 

 the Portage group at the mouth of Cashaqua creek, has been found in other 

 places. The characters are pretty uniform as far as can be ascertained from 

 the specimens, all of which are much compressed, so that the original form 

 cannot be fully determined. Greatest diameter one inch and three-fourths ; 

 and the width of the outer volution, when extremely compressed, is nearly 

 three-fourths of an inch. 



Geological formation and locality. In the green shales of Cashaqua 

 creek in the lower part of the Portage group, and in the upper part of the 

 Hamilton group at Eighteen-mile creek, Lake Erie. 

 1861.] 



