TRENTON LlMESTC»fE. 189 



247. 2. CYRTOLITES TRENTONENSIS. 



Pi.. XL. A. Figs. 3 a, b, c, d ; and Pi,. XLI. Figs. 1 a, b, c. 



Cyrtolite* trentonensu. Conrad, Jour. Acad, Nat. Science, 1842, Vol. viii, pag. 270, pi. 17, fig. 4. 

 Compare Eeeuliomphalxa minor, Pobtlock, Geol. Rep. Londonderry, 1843, 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 strise. 



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 Ecculiomphalus minor, 

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

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

 obscure fossil, occurring as ceists 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 e. Lower surface of the same. 

 Fig. 3 d. Dorsal view. 



Plate XLI. 

 Fig. 1 *. Lower surface of an imperfect specimen. 

 Fig. 1 ft. A portion of the surface strias enlarged. 

 Fig. 1 e. 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 the Mohawk valley, associated with Isotelus, S^c; and 

 in the same rock at Carlisle, Pa. (State Collection; Cabinet of Ui. Conrad.) 



* Mr. Morris {Catalogue of British Fosailt, p. 216) regards Cyrtolites as identical with Ecculiomphalus, and 

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

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

 will include thoae forms like the one under consideration. 



