lations of gravels and clays were left by the retreating
glaciers. The delta has already spread westward into the sound,
until it has enveloped some of the smaller islands. The forests
growing upon these islands, which rise from the surface of the
delta plain, are in picturesque contrast to the fields dotted with
stacks of grain.

The delta is now practically joined to the eastern side of the
San Juan Islands. The railroad reaches the islands by means of a
trestle across the intervening tidal flats, delivering its load
of logs at the mills and leaving the passengers at the town of
Anacortes, where they may take one of the many steamers passing
up and down the sound.

[Illustration: FIG. 57.--THE DELTA OF THE SKAGIT RIVER

Enveloping former islands in Puget Sound]

Of all the deltas now forming about Puget Sound that of the Skagit
is the largest and most interesting. One might think that the forests
would so protect the slopes that erosion would not be rapid, but
the valleys of all the tributary streams appear deeply filled with
rock fragments, which have, for the most part, accumulated from the
higher portions of the range, where frost and ice are slowly tearing
down the cliffs. At each period of flood some of this material is
passed on to the river, which in turn drops it upon the borders
of its delta.

The Skagit River, from its source to its mouth, takes the traveller
through varying climates and life zones, from the barren crest
where the miner is the only inhabitant, down through forests where
the lumberman is busy, until it leaves him upon the rich meadows
of its delta.

THE STORY OF LAKE CHELAN

Chelan is the largest and most beautiful of our mountain lakes.
The lake itself is most attractive, and the basin in which it lies
has had an interesting history, so that it is well worth study.

Notwithstanding the beauties of this lake, it is not widely known,
for it is situated far away from the main lines of travel, in a
remote canon of the Cascade Range. Fortunately the lake and the
rugged mountains about it have been included in a forest reserve,
so that they will be kept in all their wild natural beauty.

The Columbia River, in its crooked course across the state of
Washington, follows for some distance the junction of the vast
treeless plateau of the central portion and the rugged, forest-clad
slopes of the Cascade Range. We have already learned how the plateau
grew to its present extent through