12 PALjEONTOLOGY of NEW-YORK. 



Position and locality. This species occurs in the higlier calcareous layers of this rock, at 

 several places on the Mohawk ; at Canajoharie ; and also in Lewis and JefTerson counties. 



(State Collection.) 



13. 1. TURBO DILUCULA (71. s;).)- 



Pl. III. Fig. 7. 



Subglobose; volutions few (about 3), ventricose, rapidly enlarging to the aperture; 

 shell thin? ; spire moderately elevated, obtuse ; width and height of the sliell about equal ; 



surface 1 



This fossil occurs in great numbers in the siliceous portions of the rock, usually in the 

 form of casts, or the cavities made by the shell only are preserved. The specimen figured, 

 with portions of several others, occurs in a coarse siliceous mass, partially decomposed, and 

 containing ramified veins of chalcedonic quartz. 



Position and locality. This species is found at Middlevillc, at (he locality of quartz 

 crystals ; and also at Littlefalls, Herkimer county. It occurs in the lower and middle parts 

 of the mass, and usually in porous or cavernous portions. 



14. 2. TURBO"? OBSCURA ( 71. ip.). 



Pi.. III. Fig. 8. 



Subconical ; spire ascending, obtuse ; volutions few ( 3 ■? ) , tumid, gradually increasing 

 from the apex ; height considerably exceeding the width. 



This shell differs from tlie last in the proportionally greater height, and the more gradual 

 enlargement of the volutions from the apex towards the aperture. The specimen figured 

 occurs in a calcareous sandstone, with several others, more imperfect, all of which are casts, 

 and the surfaces much eroded. 



Position and locality. This shell occurs in the upper portions of the rock, at Fort-Plain. 



15. 1. PLEUROTOMARIA'? TURGIDA (71. j?j9.). 



Pl. III. Figs. 9 and 10. 



Depressed-conical ; whorls about 4, tumid, subangulnr, rapidly increasing from the apex; 

 last whorl very large, ventricose, expanded ; height and greatest breadth about equal. 



This fossil is a rough cast of chert in a coarse siliceous mass of calcareous sandstone, and 

 consequently its characters cannot be very accurately determined. The form of the aperture 

 is very similar to that of Natica. In fig. 10, the upper part of the spire is nearly corroded, 

 and the whole surface very rough ; in fig. 9, the surface is less eroded, though otherwise 

 in a similar condition. 



Position and locality. This species was found in a loose cherty mass of the rock in 



Saratoga county. (Cabinet of Lyman Wilder.) 



