490 FOSSIL PLANTS FROM MONTANA—FONTAINE. 
4 
permit positive determination. In size and general character it is 50 
close to Equisetum Lyelli that the identification with that species is 
quite probable. Two or three other imprints of stems occur that may 
be those of Equisetum, but they are too obscure to be determined even 
generically. ; 
Aspidium montanense, nov. sp. 
Pl. xxxxu1, Figs. 1-3; Pl. uxxxxin, Figs. 2, 33, 3a. 
Plant probably arborescent. Fronds large, probably attaining the 
dimensions of several feet, tripinnatifid or tripinnate. Pinne alternate, 
sometimes nearly opposite. Rachises of all orders strong and rigid. 
Leaf substance thick and durable. Normal pinnules, or those of the 
middle portion of the fronds and pinne, oblong, slightly faleate, obtuse to 
subacute, attached by a somewhat widened base, united at the base, 
inserted under an angle of 45° to 50°. Mid nerves of the pinnules dis- | 
tinet, continued to near their tip, and forking at the summit. Lateral 
nerves slender, single, arching towards the summit of the pinnules with 
the basal ones sometimes once forked. The pinnules of the lower part | 
of the frond are lobed or toothed, with lobes and teeth similar in shape 
to the normal pinnules. Towards the upper or terminal portion of the 
frond the ultimate pinne pass, by continued diminution, through lobed 
and toothed pinnules into entire ones. Soriin two rows, one on each side 
of the midrib of the pinnules, obovate in form, attached to the summit 
of lateral nerve and placed midway in the lamina of the pinnule. 
This fern is represented in the collections by numerous well-preserved — 
specimens, which show all parts of the frond. Pl. LXXxttl, Fig. 2, repre-— 
sents the normal pinnules. Pl. LXxx1l1, Fig.1, gives the pinnules from the 
lower part of the frond. Fig.3 shows dentate pinne, passing into pin-— 
nules, fromthe upper part of the frond. Pl. LX xxi, Fig. 3, shows lobed 
pinne from the upper part of the frond, and Pl. Lxxxtl, Fig. 2, gives _ 
fragments of a fructified compound pinna. 
This plant shows considerable variation in the ultimate pinne and 
pinnules taken from different parts of the frond. In the general char- 
acter of its pinnules it stands midway between two ferns from the Po- 
tomac of Virginia. These are Aspidium fredericksburgense Font., and 
Pecopteris strictinervis Fout. Some of the specimens, taken by them- 
selves, might easily be mistaken for the one or the other of these species. 
I think that the fern that I reported to Dr. Newberry as Aspidium fre- 
dericksburgense (see p. 193 of his paper) is a form of the species now de- 
scribed. The fructification is much like that of Aspidium pinnatifi- 
dum.* 
Aspidium monocarpum, sp. nov. 
Pl. LXXxu1I, Figs, 4-6, 6a; Pl. LXxxIv, Fig. 3, 3a. 
Frond tripinnate. Pinne alternate. Pinnules of the lower part of 
the frond attached by a much widened base, inclined strongly forward, 
“U.S. Geol. Survey, Monograph xv, Pl. xx1, Fig. 15a. 
