PRESENT VEGETATION OF THE SIERRA NEVADA. 233 
It having been stated that remains of fossil plants are abundant in the 
gravel deposits, one of the first questions to be examined in this connection 
is: In what way are they distributed? Are they found in such positions as 
to indicate an effect produced by difference of altitude or of latitude? We 
know that the present vegetation of the Sierra Nevada, as is always the case 
in mountain ranges of considerable elevation, shows in the most marked 
degree the effect of change of altitude, and that the element of latitude 
also plays a part which is especially conspicuous in the distribution of the 
forest growth of that chain. 
There are at the present epoch four pretty well marked belts of vegetation 
on the western slope of the Sierra. These belts, however, pass gradually 
into each other, and are not so defined that lines can be drawn exactly limit- 
ing their range. Still, in the central portion of the State the succession of 
the different groups of species as we rise in altitude is very easily recognized. 
The great predominance of coniferous trees is the most conspicuous feature 
of the arboreal growth of the Sierra. Even in the lowest belt,— that of the 
foot-hills, — which extends up to an altitude of between 2,000 and 3,000 feet, 
the pines are decidedly superior in number to the oaks, the digger-pine (P. 
Sabiniana) and the black oak (Q. Sonomensis) being the predominant species. 
With these two trees are mingled some quite conspicuous shrubs, some of 
which attain to considerable height. Of these the California buckeye (#seu- 
lus Californica), the Manzanita (Arctostaphylos glauca), and the Ceanothus are the 
most striking, as helping to give some variety to what, on the whole, is a 
decidedly monotonous vegetation. The next succeeding belt, which ranges 
up to 4,000 or 5,000 feet, is peculiarly the forest zone of the Sierra, distin- 
guished by the great size and beauty of the individual trees, but still without 
sufficient variety and intermixture of deciduous foliage to be beautiful as 
well as grand. The pitch pine (P. ponderosa), the sugar pine (P. Lambertana), 
the white cedar (Libocedrus decurrens), and the Douglas spruce (Abies Doug- 
lasi’) are the principal trees of this belt, in which also the Big Tree (Seguova 
gigantea) belongs, although the latter is quite limited in its range. Above the 
zone of pines come the firs, Picea grandis and amabilis, with a considerable 
number of the pine characteristic of high altitudes, the so-called tamarack 
pine (P. contorta). This belt of firs ranges, in the Central Sierra, from 7,000 
to 9,000 feet, P. monticola, in many localities, rather usurping the place of the 
firs at very high elevations, while a variety (as considered by some botanists) 
of P. ponderosa, P. Jeffreyi, is also of somewhat common occurrence. Above 
