230 
PALEONTOLOGY OF NEW YORK. 
mersed appearance. Mesopores very minute, generally only a single series 
between adjacent apertures. There are numerous, comparatively, very 
strong conical nodes, each one occupying the place of a mesopore, and fre¬ 
quently forming the most conspicuous feature of the surface. 
This species may be distinguished from F. multaculeata by the smaller, 
more closely and regularly disposed cell apertures; the nodes are much 
stronger, fewer in number, and are situated not on the peristomes, but between 
the cell apertures, replacing a mesopore. From F. densa it may be distin¬ 
guished by its smaller, less closely disposed cell apertures, less numerous and 
much more prominent nodes, and absence of monticules on which the cell 
apertures are larger than on other portions of the frond: from F. segregata by 
the smaller, more oval, much more closely and regularly disposed cell apertures, 
smaller mesopores and the prominent nodes: from F. micropora by the slightly 
larger, more decidedly oval, and more closely disposed cell apertures, compara¬ 
tively smaller mesopores and prominent nodes: from F. minuta by the smaller, 
more decidedly oval cell apertures, smaller mesopores, and more prominent nodes, 
which are situated between the apertures, and not on the peristomes and mar¬ 
gins of mesopores as in that species : from F. involvens by the somewhat larger, 
more oval and more closely disposed cell apertures, there being but a single 
series of mesopores between adjacent apertures, and also by the prominent 
nodes: from F. intercellata, of the Upper Helderberg group, by the smaller cell 
apertures, thinner peristomes and more prominent nodes: from F. mediopora , 
of the Lower Helderberg group, by the smaller cell apertures, much smaller 
mesopores, and more prominent nodes : from F. parasitica , of the same geolog¬ 
ical horizon, by the more closely and regularly disposed cell apertures and the 
prominent interapertural nodes. 
Formation and locality. Hamilton group, West Hamburg, Erie county, N. Y. 
