TUENTON LIMESTONE. 189 



247. 2. CYRTOLITES TRENTONENSIS. 



Pl. XL. A. Figs. 3 a, b, c, d ; ami Pl. XLI. Vi'fii. 1 a, b, c. 



CyrtoUtes trcntoncnsin. Conrad, Jour. Acad. Nat. Science, 18-12, Vol. viii, pag. 270, pi. 17, fig. 4. 

 Compai-e Eeciilioiiiplialus minor, Portlock, Gcol. Rep. Londonderry, 1813, pag. 412, pi. 30, figs. 11 & 12. 



Shell slender, angular, gradually curving and tapering to an acute point, making rather 

 less than an entire volution ; dorsal and ventral margins angulated or subcarinated ; lower 

 side distinctly angulated ; upper side less prominently angulated, and suddenly contracted 

 on the inner margin ; section subquadrangular ; aperture scarcely expanded ; surface 

 marked by obliquely transverse striaj. 



This peculiar little shell has the appearance of a claw or talon, making from two thirds 

 to nearly an entire volution. It bears considerable resemblance to Ecculiomphalns minor, 

 cited above. It differs in some important characters from the typical species of CyrtoUtes of 

 Conrad, which he describes, however, as being in form like Cyrtoceras* It is usually an 

 obscure fossil, occurring as casts of the interior, and destitute of surface markings. 



Plate XL. A. 



Fig. 3 a, b. View of the upper surface of two individuals. 

 Fig. 3 c. Lower surface of the same. 

 Fig. 3 d. Dorsal view. 



Plate XLI. 

 Fig. 1 a. Lower surface of an imperfect specimen. .- 



Fig. 1 b. A portion of the surface strise enlarged. 

 Fig. 1 c. Section of the shell below the aperture; the upper side of the figure being the dorsal margin. 



Position and locality. In the higher strata of the Trenton limestone at Middleville ; in a 

 lower position, in the same rock, on tlic Moliawk valley, associated with Isotelus, fyc; and 



in the same rock at Carlisle, Pa. (State Colleclivn ; Cahinet of Mr. Co.vRAD.) 



' Mr. Morris (Catalogue of British Fossils, p. 21G) regards CyrtoUtes as identical with Eccnliomphalvs, and 

 remarks that the former should be retained. Although unwilling to allow tlie present and succeeding species to remain 

 under CyrtoUtes, I have so arranged them for the present; believing that the Genus EcculiompUulus, or some other, 

 will include those forms like the one under consideration. 



