50 



PALEONTOLOGY OF NEW-YORBTi 



even with the surface, but this may be due to removal of the incrusting shaly matter with a 

 brush, in cleaning, which has also broken off the projecting papilte ; for in other specimens in 

 shale, the pores are quite prominent. The non-poriferous face is distinctly striate longitudinally 

 though often appearing smooth or granular. The size and form of the fenestrules in different 

 specimens is variable ; but after examining a large number of specimens, I am unable to find 

 any specific distinction. 



Fig. 3 a. The poriferous face of a portion of a frond (the specimen preserved in shale). 



Fig. 3 b. The non-poriferous face of another individuaL 



Fig. 3 c. A portion of 3 a enlarged, the pores still scarcely visible. 



Fig. 3 d. A portion of the non-poriferous face of 3 J enlarged. 



Figs. 3 e, f, g, h. The poriferous face of two small fragments from calcareous strata, natural 

 size and enlarged* In these the pores are very prominent, and the fenestrules dif- 

 fering in size and form in the two specimens. 



Position and locality. In the green shale at Sodus and Rochester, New- York ; and in the 

 thin calcareous layers at Flamborough Head, Canada West. (State Collection.) 



432. 1. FENESTELLA PRISCA 1 



Pl. XIX. Fig. 4 o - OT. 

 Fenestella prisca. [?] Lonsdale, Sil. System, pag-. 178, pl. 15, fig'. 18 a, b, c. 



ComTpare Hetepora prisca, Goldfuss, Petrefacta Germania, pag. 103, taf. xxxvi, fig. 19 a, 6, c 

 Frond cyathiform, much expanded ; externally the branches are irregularly dichotomous, with 

 the edges thin and sharp j transverse or connecting bars very indistinct ; a row of round pores 

 on each side of the branch ; fenestrules oval, varying in size and shape to oblong and quadran- 

 gular ; non-poriferous surface of branches striated. 



This species resembles very nearly that of Mr. Lonsdale, though we cannot compare ac- 

 curately. I have not been able to count the number of pores in each fenestrule, since the pori- 

 ferous face is somewhat obscure, and the transverse bars are very thin, and do not rise from 

 the inner face so high as the pores. 



This species is very abundant in the soft shales, and in the arenaceous shales of the Clinton 

 group. The calcareous matter of the coral has often been removed, and the impressions only 

 are left. In this condition we find the little elevated portions of stone filling the non-poriferous 

 face to be oval or quadrangular, but not often much elongated. The impression of the poriferous 

 side usually presents only the marks of the thin-edged branches, with a row of projecting points 

 on each side of the solid space between, which were the filling of the pores. In such specimen?, 

 sometimes we see slight impressions of the transverse bars upon the interspaces, but so slight 

 as scarcely to attract attention. In the coral itself the quadrangular spaces arise from a partial 

 wearing down of the non-poriferous face, so that the bars, which are thickened on their internal 

 face at their junction with the branches, giving the oval fenestrule, are worn down to a line 



