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PALEONTOLOGY OF NEW YORK. 
quently with numerous, irregularly disposed, small conical nodes. The 
branches are sometimes regular, at other times very irregular. Interstices 
wider than the branches. Dissepiments strong, width usually about .50 mm., 
on a plane with the branches or elevated above, sometimes continuing across 
the branch, coalescing with those of adjacent branches and forming continuous, 
very irregular transverse ridges, which are more prominent than the branches, 
often giving to the frond a reticulated appearance, five dissepiments in the 
space of 5 mm. Fenestrules oval, length .50 mm., width from .30 to 40 mm. 
On the celluliferous face the frond is more regular. Dissepiments rounded, 
very much depressed. Fenestrules smaller than on the 'opposite face. Cell 
apertures in two ranges, opening directly outward, twenty in the space of 5 
mm., closely disposed, nearly or quite in contact: margins thin, distinctly 
elevated, indenting the borders of the fenestrules. Surface between ranges 
of apertures carinated ; carina about .50 mm. in height, at first thin, expanding 
for about one-half the height, then contracting, the summit being thin ; on 
each margin of the expanded portion there is a row of small triangular nodes, 
about equal in number to the cell apertures. There are also, at irregular 
distances, but always over a dissepiment, semicircular projections, extending 
half way to the adjacent carina ; these when occurring opposite to each other 
frequently coalesce 
The non-celluliferous face of this species resembles that of F. interrupta , but 
the branches are smaller; the celluliferous face may be readily distinguished 
from any other species of this formation by the semicircular projections on the 
dissepiments; from F. labiata of the Hamilton group, it may be distinguished 
by its smaller and more closely disposed branches and dissepiments, the 
presence of nodes on the carinse, and the more irregular appearance of the 
non-celluliferous face. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
