GASTEROPODA OF THE LOWER GREEI^r MARLS. 75 



VOLUTOMORPHA (PlESTOCHILUS) MUCRONATA. 



Plate VI, Figs. 13-14. 

 Valuta mucronata Gabb: Proc. Acad. Nat. Sci., Phila., 1861, p. 323; Meek, Check 



List Cret. and Jur. Foss., p. 31. 

 Volutilithes mucronata (Gabb) Meek : Geol. , N. J. , Newark, 1868, p. 730. 

 Volutilithes nasuta (Gabb) Meek, loc. cit., not of Gabb. 

 Volufomorpha mucronata Gabb: Proc. Acad. Nat. Sci., Phila., 1876, p. 393. 



Shell, as exhibited in the casts, slender, with an elevated and slender 

 spire and prolonged rostral beak, giving an elongate, fusiform outline; 

 volutions five or more, moderately convex and with strongly marked suture 

 lines; body volution, as seen from the front, forming considerably more 

 than half of the length of the entire shell, and the aperture two-thirds as 

 long as the body volution; elliptical in outline, angular above and pro- 

 longed below ; columella slender, marked by two very oblique folds, which 

 are situated somewhat below the middle of its length, the lower being 

 much the stronger of the two; surface features unknown. There is the 

 slightest evidence on two individuals of distant longitudinal folds on the 

 second volution, but not sufficiently distinct to give grounds for a positive 

 assertion that such characters existed. 



This species can be confounded only with V. hella, and not very easily 

 with that one, when the proportions of parts are taken into consideration. 

 In that one the aperture will form fully or more than one-half of the 

 length of the shell, while on this one it will not exceed one-third, and 

 together with the half of the body volution above it, as seen in front, forms 

 only about the same proportion of the whole as the aperture does in that 

 species. The volutions are also less compact, and the general form more 

 slenderly fusiform, so there is but little danger of any confusion in regard 

 to the two species. In general form these shells would seem to be more 

 properly related to the Mitras than to the Volutes, but on all specimens 

 on which I have found the impressions of the columellar folds the lower or 

 anterior one has been the largest, while in the Mitridce the reverse should 

 be the case. 



Formation and locality: In a very dark colored bed of marl belonging 

 to the lower layers,' at Freehold, New Jersey. Collection at Rutgers Col- 

 lege, New Jersey. 



