Bd. Ill: 14) 
THE MESOZOIC FI, ORA. 
37 
the upper part of a frond or pinna. PI. 4, fig. 12, shows a fragment which is pro- 
bably the top of a large pinna from the lower part of a frond; it may belong to 
another species. 
The present species does not seem to be identical with any hitherto known, 
being characterized especially by the dense habit and the broad winged rachis. The 
nearest analogy seems to be found in some specimens from the North American 
Potomac P'ormation figured by FoNTAINE (1889). This is the case especially with 
some specimens of Thyrsopteris elliptica (/. c., pi. 24, fig. 3; pi. 56, figs. 6, 7), Th. 
pecopteroides (/. c.^ pi. 51, fig. i) and Aspidiiim parvifolium (/. pi. 24, fig. 8; 
pi. 25, fig. 10; pi. 26, figs. I, 14, 16, 17). All of these, however, differ considerably 
from our species in the shape and the mode of dissection of the pinnæ, and especi- 
ally in the fact that the pinnules diminish more rapidly in size from the base of the 
pinnæ upwards. Also, the venation in these North American ferns seems to be 
much more distinct, at least to judge from Fontaine’s figures, which, however, leave 
much to be desired. Another form with which this species may be compared is 
Dickso 7 iia Zarecznyi Raciborski (1894; P^- 7 — 16); but this agreement does 
probably not amount to specific identity. A certain resemblance to Sphenopterds 
Fittoiii is noticeable, too ; but on the whole this is more remote. There is also a 
marked resemblance in general habit to the fronds described here as Splienopteris 
pecteii (p. 35). The latter form, however, must be referred to Sphenopteris on ac- 
count of the venation and the thinner pinnules. Other differences are stated under 
the species mentioned. 
The species is one of the more common ones and is represented by a fairly 
large number of specimens. 
Scleropteris furcata n. sp. 
ri. 4, figs. 3, 10, II, I 3 ~i 8 , 19?, te.\t-fig. 9. 
This species has been referred to Scleropteids on account of the structure and 
venation of the pinnules; but in regard to the general shape and branching of the 
frond, it represents an isolated type within that genus. 
Rachis of the frond dividing into two branches, which alone bear pinnæ. The 
lowest outer pinna, just at the base of each branch, much larger than the others, and 
with deeply dissected pinnules, which resemble the upper pinnæ. Pinnæ generally 
opposite or sub-opposite, distant and at a fairly open angle to the rachis. Pinnules 
entire, or the lower ones in each pinna with one or two pairs of small, rounded 
basal lobes. All pinnules oblong to obovate or rounded with very broad and rounded 
upper end and tapering at the base. Laminæ of the pinnules thick and venation 
ndistinct, consisting of a little marked median vein and few, forked branches of 
nearly equal strength. Fructification not known. 
