518 
PALAEONTOLOGY OF NEW-YORK. 
I have recognized in the Clinton group of New-York a species cor¬ 
responding to this generic description, the R. venosus (Pal. New-York, 
Yol. ii, pa. 40, pi. a IT, f. 2), which is there described as a Graptolithus. 
In the Report on the Geological Survey of Canada for 1857, I have de¬ 
scribed two other species. An examination of some specimens of another 
similar form from the Hudson-river shales near Albany (New-York) has 
convinced me that one of these is sufficiently distinct to form the type of 
a new genus, for which I have proposed the name Reteograptus, from 
its reticulated structure, and from the absence of serratures or cellules 
reaching to the axis. 
Reteograptus geinitzianus (n. s ). 
Stipes small, sublinear; sides essentially parallel. Enveloping crust of the 
stipe finely veined, somewhat thickened : the skeleton reticulate with 
three or more rows or series of subquadrangular reticulations, without 
midrib or central axis : no defined cellules or serratures ; margins with 
projecting mucronate or recurved spinules. 
The specimens are nearly all deprived of their outer 
crust, leaving the skeleton alone. 
The accompanying figure is from a specimen, twice 
enlarged. 
Geological position and locality. In the shales of the 
Hudson-river group : Near Albany. 
I am by no means certain that this fossil, in its perfect condition, or in all its 
stages of growth, consists of three rows of cells. The structure and mode of growth 
in these forms indicates that the cells increase by lateral extension; and a single 
fragment in the collection gives some evidence of four rows of reticulations, as in 
other forms of the genus. It is not improbable, also, that in entire specimens we may 
find evidence of a central axis; since the implied mode of growth, in its similarity 
to that of the graptolites, indicates this structure. 
