The coastal plains produced by uplift of the land may be fertile
and may furnish happy homes for man, but they do not permit ready
access to the sea because they have no harbors. The chief harbor
of Mexico at Vera Cruz is merely a little nick in the coast-line
and could never protect a great fleet, even with the help of its
breakwater. Where an enterprising city like Los Angeles lies on
the uplifted Pacific coast, it must spend millions in wresting a
harbor from the very jaws of the sea.

In high latitudes in all parts of the world the land has recently
been submerged beneath the sea. In some places, especially those
like the coasts of Virginia and central California which lie in
middle latitudes, a recent slight submergence has succeeded a
previous large emergence. Wherever such sinking of the land has
taken place, it has given rise to countless bays, gulfs, capes,
islands, and fiords. The ocean water has entered the valleys and
has drowned their lower parts. It has surrounded the bases of
hills and left them as islands; it has covered low valleys and
has created long sounds where traffic may pass with safety even
in great storms. Though much land has thus been lost which would
be good for agriculture, commerce has been wonderfully
stimulated. Through Long Island Sound there pass each day
hundreds of boats which again and again would suffer distress and
loss if they were not protected from the open sea. It is no
accident that of the eight largest metropolitan districts in the
United States five have grown up on the shores of deep inlets
which are due to the drowning of valleys.

Nor must the value of scenery be forgotten in a survey such as
this. Year by year we are learning that in this restless,