No. 75.] 171 



uniting the branches, it differs from Retepora, to which it is closely- 

 allied in other respects. In the rounded branches and transverse non- 

 celluliferous dissepiments it resembles Polypora, but the cells are an- 

 gular as in Retepora, and the coral has the general aspect of that genus. 



Fig. 1, a, a specimen of this coral upon the surface of a fragment 

 of limestone. In some parts the coral appears to be distinctly retic- 

 ulated, while in others the branches are united by transverse bars. 



Fig. I J by a. portion of the poriferous surface enlarged. 



Fig. 1, c, another fragment, having elevated nodes upon the surface 

 of the branches. 



Fig. 1, dy an enlarged portion of the non-poriferous face. 



Fig. 1, e, a similar fragment of the non-poriferous face, partially cov- 

 ered by an incrusting coral which has the character of Chaetetes. 



This species occurs in the lower part of the Trenton limestone, near 

 Lowville, Lewis county. {State Collection.) 



^GILOPS, {new genus.) 



Inequilateral, valves, somewhat trigonal, rounded on the base, slop- 

 ing abruptly from the beaks, which are incurved at the extremity. 



.EGILOPS SUBCARINATA. 

 Plate 4, Eg. 1, a, b. 



Trigonal, with the beaks much elevated and incurved ; anterior slope 

 short, ending in a slightly rounded extremity, which continues into the 

 curve of the rounded base ; posterior slope long and straight ; surface 

 meirked by a rounded ridge or carina extending from the beak nearly 

 to the base, and margined on each side by a corresponding depres- 

 sion. 



The form of this shell is peculiar and characteristic, the inequal- 

 ity of the valves is only apparent or due to pressure. It is clearly 

 the type of a genus which has not hitherto been noticed in the lower 

 Silurian rocks of this country, if in Europe. 



This species was found in the Trenton limestone, near Lowville, 

 Lewis county. {State Collection.) 



MURCHISONIA SUBFUSIFORMIS. 

 Plate 4, fig. 2. 



Reference. — Palaeontology of New- York, vol. i, page 234, plate 39, 

 fig. 2. 



The two figures of this fossil referred to, give but a very imperfect 

 idea of the species. Nearly all the specimens procured are so mutila- 



