he flooding of their fertile lands! But we can understand how
small the loss would have been, compared with the advantages to
be gained from the magnificent harbor which now exists here. If
the land had not sunk the history of the Pacific coast would have
been far different.

[Illustration: FIG. 36.--ISLAND ROUNDED BY A GLACIER

Near Anacortes, Puget Sound]

Puget Sound, another very important arm of the ocean, is also a
submerged valley, but it has had an entirely different history
from that of San Francisco Bay. The valley was at one time occupied
by a great glacier which came down from the Cascade Range and moved
northwest through the sound and into the Strait of Juan de Fuca,
scouring and polishing the rocks over which it passed. A little
island near Anacortes (Fig. 36) has been rounded by the action
of the ice into a form like a whale's back.

[Illustration: FIG. 37.--AN ABANDONED OCEAN CLIFF

Southern California]

The sinking of the land flooded the lower Columbia River and the
mouth of the Willamette, so that ocean ships may now go up as far
as Portland. The currents and waves soon threw up bars across the
mouths of the smaller streams, and formed lagoons behind them.
Ships frequently have difficulty in entering many of the harbors
because of the sand bars which have been built up part way to the
surface of the water.

It is thought that along some portions of the coast there has recently
been a slight upward movement of the land. Figure 37 shows a bit
of California coast, near San Juan, where the Santa Fe railroad
has laid its tracks for several miles along a strip of abandoned
beach, at the base of a cliff against which the waves once beat.

[Illustration: FIG. 38.--LIMESTONE CLIFF, QUATSINO SOUND, VANCOUVER
ISLAND]

At the northern end of Vancouver island there is a deep arm of
the ocean called Quatsino Sound. A limestone cliff upon the shore
of this sound (Fig. 38) has been undermined by the dissolving of
the limestone, but now the water lacks three feet of rising to
the notch which it recently formed.

THE DISCOVERY OF THE COLUMBIA RIVER

The influence exerted by the various features of the land and water
upon the settlement of a new region are not always fully appreciated.
If the entrance to San Francisco Bay had been broader and more
easily discerned by the early navigators who sailed past it, and if
the mouth of the Columbia River had not been obscured by lowlands
and a line of break