40 
PALEONTOLOGY OF NEW-YORK. 
417. 16. GRAPTOLITHUS VENOSUS (n.sp.). 
Pl. A. XVII. Fig. 2 a, b, c. 
Stipe rather broad, linear, rigid, serrated on both sides ; serrae short, acute, distant, the spaces 
between curving into the substance of the stem; substance composed of reticulated or venose 
threads. 
This very peculiar species differs from all the others in a sufficient degree to be readily 
identified. The substance is very thin and fragile, and scarcely recognizable without a glass ; 
but when once the peculiar venose structure is discovered, it is readily detected afterwards. 
The peculiar serrae, or emarginations of the two margins, is also a very peculiar and distinctive 
feature. By these characters the smallest fragment is readily distinguished, and its difference 
from all known species is at once clearly observable. 
Fig. 2 a. A piece of slate, with numerous fragments of G. clintonensis and G. venosus. The latter 
are much more indistinct than the former, and can scarcely he brought out without a 
magnifier. 
Fig. 2 b. A fragment of G. venosus enlarged. 
Fig. 2 c. A fragment (enlarged), which appears to he the upper extremity of the stipe of this 
species. With the exception of this figure, no terminations of either species have been 
seen. They occur in fragments of various lengths, having a pretty uniform character 
throughout. 
Position and locality. This species occurs with the preceding one in the same thin black 
layers in the green shale below Rochester. (State Collection.) 
101. 2. CHiETETES LYCOPERDON. 
Pl. XVII. Figs. 1 a - l. 
A species, which I am unable to distinguish from the one in the Trenton limestone and 
Hudson-river group, occurs in considerable numbers in the Clinton group. In this position, 
however, it never attains those massive hemispherical forms which are so abundant in the Trenton 
limestone. It is almost always found in the branching form ; and the others, though sometimes 
seen, are thin, and never attain any considerable bulk. 
Fig. 1 a. The upper surface of a flat massive form. 
Fig. 1 b. Figure showing the height of the same specimen. 
Fig. 1 c. The lower surface of the same specimen. 
Fig. 1 d. Section of a small hemispheric mass. 
Fig. 1 e. Several columns enlarged. 
Fig. 1 f Openings of cells enlarged. 
Fig. 1 g. A raiftose specimen on limestone. 
Figs. 1 h, i, k. Sections of the branches of several ramose specimens through the centre, and on 
one side of the centre, showing the arrangement of the cells. 
Fig. 1 l. Several of the cells enlarged. 
