40 
PALAEONTOLOGY OF NEW-YORK. 
the rock is compact, we have no certain means of determining them. The latter species is 
crystallized more frequently than the former, the stem of which is tubular and usually filled 
with argillaceous matter. 
Fig. 1. Base or root of one of these fossils, with its diverging and slightly ascending branches. The 
surface, not being worn, presents no marks of structure. 
Fig. 1 a. A part of the specimen presents the longitudinal fibres, with very distant transverse fibres. 
Fig. 1 b. A longitudinal section, passing nearly through the centre of the stem, showing the longitudinal 
and transverse fibres. 
Fig. 1 c. Portion of two stems with the cuticle removed, showing the structure. 
Fig. 1 d. Oblique sections near the termination of branches (the fructiferous portions?), presenting 
stellate or cruciform cells. 
Fig. 1 a (in part), presents quadrangular cells, arranged diagonally to the direction of the stems. These 
forms may arise from weathering, or solution of cellular partitions in forms like 1 d. 
Position and locality. In the Birdseye limestone at Watertown and other places on the 
Black river, and in the Champlain valley. Specimens like figs. 1 a and 1 b are not un¬ 
common in some parts of the same rock in the Mohawk valley. {State Collection.) 
FOSSIL SHELLS OF THE BIRDSEYE LIMESTONE. 
Plate X. 
In some localities of the Birdseye limestone, where the rock is of a nature to admit of 
their development, shells are very numerous, but it rarely happens that they are sufficiently 
distinct to admit of precise description. Several species appear to be identical wilh those 
of the Trenton limestone ; but there are others, which, so far as we know at present, are 
confined to this rock alone. 
I have presented the following forms, as indicating those which have more frequently 
fallen under my own observation, though I doubt not that a more numerous collection 
could be made by farther investigations. The rock usually adheres so closely to the shell, 
that the latter separates with it, and thus the external sculpture is obliterated. We are 
compelled, therefore, to depend mainly on the form of the shells in distinguishing species. 
Their position is almost entirely confined to the higher portions of the rock, which is 
irregularly stratified, and much intermingled with shaly matter and fragments of the 
Piiytopsis. 
66. 1. MODIOLA? OBTUSA (n.sp.). 
Pl. X. Fig. 1. 
Single valve oblong, suboval, gradually narrowing towards the beak, convex ; anterior 
extremity very obtuse. Some faint lines of growth, or stria?, are perceptible. 
The specimen is a cast, nearly smooth, narrowing gradually towards the beak, and 
slightly contracted before reaching the anterior extremity. 
Position and locality. In the upper part of the rock at Watertown, Jefferson county, 
associated with PHYTOPSIS. {State Collection.) 
