MEDINAN, NIAGARAN, AND CHESTER FOSSILS 
65 
Specimen 3 is represented by both the obverse and reverse 
parts. In specimen B the lateral margins of the lobes appear 
confluescent. In several small fragments between A and B 
the lobes are conspicuously separated from one another; possibly 
only the median parts of these lobes are preserved. In B, 
the rachis-like median film is 0.5 mm. wide. The reticulating 
fibers appear to radiate more or less toward the margin of the 
lobes. Numerous hair-like fibers, 1 mm. in length, extend 
beyond the margin of the frond. Among the reticulating and 
hair-like fibers there are rows of black dots, those among the hair- 
like fibers being smaller. 
In specimen 20, the left margin of the frond is distinctly lobed, 
while the right margin is only crenulated. Apparently the 
marginal parts of the lobes are not well preserved on the dis- 
tinctly lobed side. Rows of black dots appear both among the 
reticulated and among the hair-like fibers. 
Appearance of lobation sometimes deceptive.— Some speci- 
mens which on macroscopical examination appear strongly 
lobed, on microscopical examination appear less indented, the 
lateral parts of the supposed lobes being confluescent, the loba- 
tion being confined to marginal crenulations. Specimens of 
this type are represented by figures 1, 7 A, 8, 9, and 10 on plate 
V, and b}^ figures 18 B and 21 on plate XI. Additional figures 
of specimens 8, 18 B, and 21 are found on plates VIII, XI, and 
IX respectively. 
Frond A on specimen 1 presents very well the median black 
rachis-like film. Rows of black dots are very distinct, varying 
from 6 to 9 in 1 mm. 
Specimen 8 shows very well the median rachis-like film of the 
frond, 0.4 mm. wide. The fibers within the frond form relatively 
coarse and irregular meshes. Along the central part of the frond, 
black dots occur in series, 5 or 6 in 0.5 mm. The hair-like fibers 
extend 1 mm. beyond the margin of the frond. Black dots 
along these hair-like fibers number 6 or 7 in 1 mm. The hair-like 
fibers probably were attached both to the margin of the frond 
and to its flat faces. 
