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.