294 



PALiEONrOLOGY OF NEW-YORK. 



Position and locality. In the shale of this group at Lockport, Rochester and other places, 

 and more rarely in the limestone at Lockport. 



661. 5. CONULARIA NIAGARENSIS (ti. i^;).). 



Pl. LXV. Fig. 1o-7j. 

 Compare Conularia quadrisulcata, Millek. 



" — — SowERBY, Min. Conchology, Vol. iii, 1821, p. 107, t. 260. 



" — — J- Sow.in MuRCHisoN, Sil. System, pag-. 626, pl.xii, fig. 22. 



Conularia quadrisulcata. Hall, Geol. Rep. 4th District, 1843, pag. 110, fig. 2. 



Broad, pyramidal, tapering abruptly ; angles with deep abrupt channels ; centre of each 

 side with a shallow scarcely defined depression, which produces a more abrupt bending of the 

 strias ; transverse striae fine and closely arranged, directed from the angles obliquely to the 

 centre, where they are more abruptly bent in crossing the slight depression ; striee papillose- 

 granulate, intermediate spaces marked by longitudinal striae, and grooves which alternate with 

 the points upon the transverse striae. 



This species is quite distinct from the lower silurian species ; and since the name of C. 

 quadrisulcata was applied by Mr. Sowerby to silurian and carboniferous specimens alike, we 

 are at liberty to give another name, till the application of C. quadrisulcata shall be deter- 

 mined. The Wenlock species, to which Mr. J. D. C. Sowerby has applied the name of C. 

 quadrisulcata, is probably identical with ours, holding the same geological position. 



In the Niagara species the transverse ridges are nodulose or papulose, with sharp deep 

 grooves between, which are partially crossed on the upper side of the ridge by an elevated line 

 from the papulose point of the ridge. The transverse ridges, as well as the points upon them, 

 are comparatively closer together than in the Trenton species, in which the interspace is more 

 distinctly grooved longitudinally ; while in the Niagara species the ridges are ornamented with 

 prominent distinct points, which are likewise shown in the cast, and the interspaces are nar- 

 rower and very distinctly grooved. The arrangement of the transverse striee is not equal and 

 uniform, being sometimes much more crowded for a short distance than the prevailing character. 

 From partial or entire exfoliation of the shell, and from specimens showing the interior of the 

 shell, and from casts of the same, there is considerable variety of aspect and character presented. 



Fig. 1 a. A fragment of a small specimen preserving the shell in great perfection. The striae are 



regularly and closely arranged, the intermediate spaces being scarcely wider than 



the ridges. 

 Fig. 1 b. An enlargement of this surface, showing the character of the strijE and intermediate 



spaces. 

 Fig. 1 c. An impression of the exterior of a similar specimen, where the depressions between 



the strias are distinct, and show the longitudinal striee, with the narrow punctured 



depressions between. 

 Fig. 1 d. An enlargement of the same. 



