TRENTON LIMESTONE. 
189 
247. 2. CYRTOLITES TRENTONENSIS. 
Pl. XL. A. Figs. 3 a, b, c, d; and Pl. XLI. Figs. 1 a, b, c. 
Cyrtolites trentonensis. Conrad, Jour. Acad Nat. Science, 1842, Vol. viii, pag. 270, pl. 17, fig. 4. 
Compare Ecculiomphalus minor, Portlock, Geol. Rep. Londonderry, 1843, pag. 412, pl. 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 striae. 
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 Cyrtoccras.* 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 cl. 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 the Mohawk valley, associated with Isotelus , Sfc.; and 
in the same rock at Carlisle, Pa. (State Collection; Cabinet of Mr. Conrad.) 
* Mr. Morris ( Catalogue of British Fossils, 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 Cyrtolites, I have so arranged them for the present; believing that the Genus Ecarfiomphalus, or some other, 
will include those forms like the one under consideration. 
