TRENTON LIMESTONE. 199 



Figf. 8 a. Fragments of two specimens connected by the dotted lines. The annulations are represented 



as too broad. 

 Fig. 8 b. Section showing the position of the siphuncle. 



Position and locality. This species is only Iviiown to me as occurring in the higher 

 crystalline portion of the limestone at Watertown, Jefferson county. (State Collection.) 



260. 13. ORTHOCERAS TEXTILE ( n. sp.). 



I'L. XLIII. Figs. I a,b. , ' . 



General figure cylindrical, very gradually tapering, marked by prominent transverse or 

 slightly arching annulations, which are distant about one third the diaineter of the shell ; 

 entire surface marked I)y fine longitudinal and transverse stria;, which are closely arranged, 

 the series being equidi.stant from eacii other, giving the surface the appearance of a woven 

 texture; septa rather deeply concave, distant about one third of liie diameter; section 

 circular; siphuncle'? 



This fossil bears some resemblance to O. calamitcum, as figured l)y Portlock (Geo/. Rep, 

 Londonderry, pag. 365, pi. 25, fig. \ a,b); but our specimens never present any "strong 

 longitudinal threads or stripes" passing over the annulations, the stria; being uniform in 

 this respect. It also differs essentially from 0. tuhicinella of Sowerby, which we find in our 

 Hamilton group. 



Fig. 1 a. A fragment of the natural size. 



Fig. 1 b. A portion of the surface enlarged, to show the stria;. 



Position and locality. In the lower concretionary beds of the Trenton limestone at 



Watertown. 



t' 



- - 261. 14. ORTHOCERAS BILINEATUM (n. .?/).). 



Pl. XLIII. Figs. 2 a, i, c, d. 



Compare Orthoceras calamiteum, Munster, 1S39, heft i, pag. 3G, pl. 17, fig. 5 ; Id. lS-10, heft iii, p. 102. 



— D'Archiac &. DE Verneuil, 1S42, Trans. Geol. Soc. London, 2d series, Vol. vi, 



— Portlock, Geol. Rep. Londonderry, 1843, pag. 30'), pl. 25, fig. 1. [p. 346. 



— — Verneuil, Pal. Russia and the Ural Mountains, 1845, pag. 353, pL 25, fig. 5. 



General form cylindrical, gradually tapering, marked by slightly arched or undulating 

 rounded annulations distant about two fifths the diameter; surface marked by longitudinal 

 sharp elevated lines, which alternate with finer lines in equal number ; transversely marked 

 by fine scarcely visible striie, which are interrupted by (he longitudinal lines ; section 

 circular ; siphuncle excentric. 



The two series of longitudinal lines, one being more tlian twice the elevation of the 

 other, are distinguishing features of this fossil. The annulations are more arched on the back 



