FONTAINE, } THE OROVILLE FLORA. 347 
base with acute tips. At the same time they are inclined forward in a 
peculiar manner. They can not be united with Cladophlebis spectabilis, 
the plant nearest to it that occurs at Oroville. 
This fern belongs evidently to that well-marked Jurassic type 
brought under the comprehensive name Cladophlebis whithiensis, and 
resembles Brongniart’s form more than that of Lindley and Hutton. 
CLADOPHLEBIS DENSIFOLIA Fontaine. 
Pi. LI. 
1896. Cladophlebis densifolia Font.: Am. Jour. Sci., 4th Ser., Vol. II, p. 274, 
Frond tripinnate at least. The largest primary rachis seen, given 
in Pl. LI, Fig. 1, has a width of 6 mm. The primary pinne are 
alternate and very long. The largest portions found were 14 cm. in 
length, with the basal and terminal portions not preserved. This 
portion does not change in width much throughout its length, and 
hence must belong to a pinna that was much larger than the part seen. 
The primary pinne were probably linear-lanceolate in form, and 
tapered very gradually from base to tip. They are closely placed, so 
that they overlap. The rachises are strong and rigid, going off from 
the principal rachis at an angle of 45° and curving away from it. 
The secondary pinne are alternate to subopposite and very closely 
placed so as to overlap. They gradually diminish in length and size 
from their insertions on the primary pinne to their ends. The long- 
est basal ones are about 2 cm. in length and the width of these is 
about 2mm. In shape they are oblong with subacute ends. They are 
inserted at about an angle of 45°, and are falcately curved toward 
the ends of the primary pinne. The lowest, basal, ultimate pinne 
are cut in their lower portions down to the midrib into ovate subfal- 
cate and subacute pinnules that are closely placed, but the portions 
higher up have the lamina of the leaf more and more entire, the 
incisions passing, at the tips of the ultimate pinne, into teeth. 
Higher up on the frond and more toward the ends of the primary 
pinne the ultimate ones become more and more entire and pass into 
lobed and dentate pinnules. The tip of the primary pinna has pin- 
nules and lobes like those of the ultimate pinne lower down. The 
nervation could not be made out. 
Fig. 1 represents a portion of a primary pinna. Fig. 2 gives several 
secondary pinne, placed as if they had been attached to a principal 
rachis. Fig. 3 gives the terminal portion of a frond, or of one of the 
lower primary pinne. Fig. 4 gives a portion of a lower ultimate 
pinna magnified to show details. 
This is one of the most abundant small-leaved ferns in the forma- 
tion, and it shows larger portions better preserved than any of the 
small ferns. 
