advancing fifteen or twenty miles towards Yosemite and making an ascent
of from two to three thousand feet you reach the lower margin of the
main pine belt, composed of great sugar pine, yellow pine, incense cedar
and sequoia. Next you come to the magnificent silver-fir belt and lastly
to the upper pine belt, which sweep up to the feet of the summit peaks
in a dwarfed fringe, to a height of from ten to twelve thousand feet.
That this general order of distribution depends on climate as affected
by height above the sea, is seen at once, but there are other harmonies
that become manifest only after observation and study. One of the most
interesting of these is the arrangement of the forest in long curving
bands, braided together into lace-like patterns in some places and
out-spread in charming variety. The key to these striking arrangements
is the system of ancient glaciers; where they flowed the trees followed,
tracing their courses along the sides of canyons, over ridges, and high
plateaus. The cedar of Lebanon, said Sir Joseph Hooker, occurs upon one
of the moraines of an ancient glacier. All the forests of the Sierra are
growing upon moraines, but moraines vanish like the glaciers that make
them. Every storm that falls upon them wastes them, carrying away their
decaying, disintegrating material into new formations, until they are no
longer recognizable without tracing their transitional forms down the
Range from those still in process of formation in some places through
those that are more and more ancient and more obscured by vegetation and
all kinds of post-glacial weathering. It appears, therefore, that the
Sierra forests indicate the extent and positions of ancient moraines as
well as they do belts of climate.

One will have no difficulty in knowing the Nut Pine (Pinus Sabiniana),
for it is the first conifer met in ascending the Range from the west,
springing up here and there among Douglas oaks and thickets of ceanothus
and manzanita; its extreme upper limit being about 4000 feet above the
sea, its lower about from 500 to 800 feet. It is remarkable for its
loose, airy, wide-branching habit and thin gray foliage. Full-grown
specimens are from forty to fifty feet in height and from two to three
feet in diameter. The trunk usually divides into three or four main
branches about fifteen or twenty feet from the ground that, after
bearing away from one another, shoot straight up and form separate
summits. Their slender,