60 
PALAEONTOLOGY OF NEW-YORK* 
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 papillae ; for in other specimeKS 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 fenestmles 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 b 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. I. FENESTELLA PRISCA 1 
Pl. XIX. Fig. 4 a-m. 
Fenestellaprisca. [?] Lonsdale, Sil. System, pag. 178, pl. 15, fig. 18 a, b } c. 
Compare Reteporaprisca, 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 ; 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 specimens, 
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 
