is known as
the continental plateau. The water over the plateau is comparatively
shallow. Upon one side the land rises, while upon the other there is
a rapid descent into the deep Pacific. The surface of the plateau
is in general fairly smooth, but in places mountains lift their
summits above the water and form islands.

There was a time, thousands of years earlier than the period when
California was so nearly covered by the waters of the Pacific, when
this land stood far higher than it does now. The coast line was
then much farther west, near the border of the submarine plateau.
The Santa Barbara Islands at that time formed a mountain range upon
the edge of the continental land. This fact was established by
the discovery upon one of the islands of a large number of bones
of an extinct American elephant. These animals could have reached
the submerged mountains only at a time when there was dry land
between them and the present shore line. We should like to know how
it came about that these bones were left where they are. Perhaps
the land sank so suddenly that the water cut the elephants off from
the mainland and compelled them to spend the remainder of their
lives upon these islands.

While the land stood so high, some of the larger streams wore deep
channels across what is now the submarine plateau. These channels
have been discovered by soundings made from the ships of the United
States Coast Survey. The largest of the submerged valleys extends
through the Bay of Monterey, and runs so close to the shore that
it has offered a favorable location for a wharf.

Before the buried valleys upon the northern coast of California
were all known, the presence of one of them led to the wreck of
a ship. The shore was obscured by fog, but the soundings made by
the sailors showed deep water and led them to believe they were
a long distance from land, when suddenly the ship drifted in upon
the rocks.

The last significant movement of the land of the Pacific border
was a downward one. It flooded the mouths of the streams and formed
all the large harbors which are of so great commercial importance.

San Francisco Bay occupies a great stretch of lowland at the meeting
of several valleys of the Coast Ranges and forms the outlet for
the most important drainage system of California. If this region
had been settled before the subsidence of the land which let in the
ocean through the Golden Gate, how the farmers would have lamented
t