OF DENISON UNIVERSITY. 
83 
1875. In the latter publication he states of the diagonal arrangement of 
the cells ; “ This arrangement is first seen on the branches, when the ex- 
terior layer has been removed. This layer, when best preserved, shows 
distinct longitudinal striations; by abrasion or splitting off, the inner 
portions of the cells appear arranged as stated above so‘ close to 
one another that hexagonal outlines arise.” And later: “The di- 
mensions of our specimens are very variable; the fenestrated branches 
named are sometimes broader, sometimes narrower, and in a piece 
narrower than usual, even 7 fenestrules are found in a length of 10 mm.” 
Apparently the same variations are found in our specimens. The 
largest has 5 fenestrules and 6 dissepiments in a length of 10 mm., 7 
to 9 branches occur in the same distance in breadth. In one of the 
smaller specimens, 7.3 fenestrules occur in a length of 10 mm. and 
10.5 branches in the same breadth. From 7 to 9 cells occupy a length 
of 2 mm. The fine longitudinal striae of the poriferous face of the 
dissepiments are mentioned by Toula in his descriptions. 
Common at Flint Ridge and Bald Hill. 
Perhaps we have .confounded two species in the above descrip- 
tion, one smaller than the other, or with smaller and more distant cells, 
but we fail to find definite specific characters. 
Genus FENESTELLA, Lonsdale. 
Differing from Polypora in the presence of a median keel, the 
cells being arranged in two rows, one on either side of the keel., 
X. Fenestella limbatus, sp. n. 
{Plate VII, Fig. 10, a., b, c, d.) 
In the limestones at Flint Ridge and Bald Hill are found numer- 
ous specimens belonging to the genus Fenestella, all of which have the 
following features in common. The zoaria are infundibuliform ; the 
inner side is poriferous ; the median keel is well developed and dis- 
tinct, along the summit it is occupied by a single row of rounded 
nodes stationed at regular distances apart, and calling to mind such 
PolyporcB as may be typified by Polypora submarginata, Meek, for in- 
stance, (Pal. East. Nebr. Meek, 1872); the nodes often appear hollow, 
where abraded, but never alternate with small pores as in the species 
just cited. The nodes are somewhat more numerous than the cells. 
Another equally characteristic feature is the form and arrangement of 
