346 OLDER MESOZOIC FLORAS OF UNITED STATES. 
A considerable number of specimens of a small fern were obtained 
that agree so well with Heer’s Aspleniwm argutulum that it may with- 
out much hesitation be identified with it. Heer’s plant was obtained 
from the Jurassic formation on the upper Amur River, the same that 
yielded C. spectabilis.. Most of the Oroville specimens are frag- 
mentary and distorted by pressure. This is the case with the form 
represented in Fig. 1, and in consequence of this the pinnules appear 
tore united and wider than in Heer’s normal forms. 
This is the most common small-leaved fern at the Oroville localities. 
It occurs at most of them, but is most abundant at the locality ‘“‘In 
the bed of a ravine that leads from 4he Banner mine to the Feather 
River,” ete. 
Fig. 1 gives the upper part of acompound pinna. Fig. 3 represents 
several detached ultimate pinne from the lower part of the frond, and 
Fig. 4 gives a pinnule of the same enlarged to show details.’ 
CLADOPHLEBIS WHITBIENSIS TENUIS var. a Heer? 
Pl. L, Fig. 7. 
1876. Asplenium (Diplazium) whitbiense tenue var. a Heer: Jura-Flora Ostsibiriens, 
Fl. Foss. Arct., Vol. IV, Pt. II, pp. 24, 39, 95, 118, 120, pl. iii, figs. 3, 3b; 
pl. xx, figs. 2, 3a; pl. xxi, figs. 3a, 3b, 4, 4b. 
1896. Cladophlebis whitbiensis tenuis var. a (Heer) Font.: Am. Jour. Sci., 4th Ser., Vol. 
Il, p. 274. 
Two small fragments of a fern that is without doubt of the whztbzensis 
type were found at ‘‘The old dump at the Banner mine.” Both are 
the terminations of ultimate pinne, parts of ferns that have little value 
in fixing character, and hence, as the amount of material is so small, 
the identity of this fern must remain in doubt. It is, however, clearly 
different from the other ferns found at Oroville, and is so much like 
the form described by Heer* from the Jurassic of Siberia that it may 
be provisionally identified with it. The Oroville plant may be com- 
pared with fig. 2 of Heer’s pl. xx. The plant has a sharply defined 
character marked by the possession of pinnules that are very broad at 
1Flora Foss. Arct., Vol. IV, Pt. II, Beitrige zur Jura-Flora Ostsib. und des Amurlandes, p. 96, pl. 
xix, figs 1-4. 
? After Professor Fontaine had studied the specimens it was observed that there was a counterpart 
of the upper part of the specimen, Fig. 1, which shows the details somewhat better, and this isshown 
in Fig 2. A small piece on the left of the portion of the large slab, designated Fig. 3 by Professor 
Fontaine, split off, revealing the pinna included in that figure, which lies in the opposite direction 
and is not in the same plane as the others on the rock. The reverse of thison the small piece thus 
split off shows more than the side adhering to the large slab, and is represented in Fig.5. The per- 
fect pinnule near the top of this on the left is given in Fig. 6, enlarged two diameters. 
L. F. W. 
3It is not worth while to attempt to work out the synonymy of this form, as it is clearly different 
from the original Pecopteris tenuis Schouw, Mss., based on a specimen in Prince Christian’s Museum 
and figured by Brongniart in his Hist. Vég. Foss., Vol. I, pl. ex, fig. 4, and the whole group needs 
revision. L. F. W. 
4Flora Foss. Arct., Vol. IV, Pt, I, Beitrige zur Jura-Flora Ostib. und des Amurlandes, p. 95, pl. xx, 
figs. 2, 3a. 
