9 FOSSIL FLORA OF THE SIERRA NEVADA. 
DICOTYLEDONES. 
AMENTACEA. 
BETULA, L. 
Betula squalis, sp. nov. 
Pil. I. Figs. 2-4. 
Leaves elliptical-ovate, equally narrowed up to a sharp point and downward to a short 
petiole ; borders equally dentate ; secondary veins mostly simple, craspedodrome. 
The form of the leaves is the same in all the specimens, differing only 
by their size, from five to eight centimeters long, and from two to three 
and a half centimeters broad. The secondary veins are mostly simple, 
either slightly curving in passing up to the borders in an acute angle 
of divergence of .30° or straight, entering the alternate teeth and some- 
times the intermediate ones by short branches, as in Fig. 2. The lower 
pair of lateral veins join the middle nerve a little above the base of the 
leaves, which is generally bordered, at least on one side, by a thin mar- 
ginal veinlet; they are parallel, equidistant, opposite in the lower part 
of the leaves, alternate in the upper part, eenerally separated by a thin 
tertiary vein dissolved below the middle of the areas; the teeth, nearly 
equal, are sharp, and slightly turned upwards. 
The relation of this species to the present Betula occidentalis, Hook., 
commonly found along the streams of the Rocky Mountains, is very close 
indeed. The nervation is the same; the nearly equal teeth are, in some 
leaves at least, of the same form and size; the difference is only in the 
shape of the leaves, which in the fossil species are longer, wedge-form 
to the base, and also proportionally narrow. A fine representation of 
this Betula is given in Watson’s “Botany of the Fortieth Parallel,” Pl. 
XXXV. Among the fossil species, ours is comparable to B. Brongnartt, 
Ett. Fos. Fl. v. Bilin, L, p. 46, Pl. XIV. Figs. 9-13, which is common in 
the Miocene of Europe, and has been described also by Heer, Gaudin, 
Saporta, and other paleontologists. The affinity, however, is more marked 
with the living American B. occidentalis than with any fossil forms known 
as yet of this genus. 
Habitat. — Chalk Bluffs, Nevada County, California. Voy’s Collection. 
