erfalls, and rapids due to recent
glaciation in the east. Nevertheless, though youth is the condition of
most striking beauty, maturity and old age are the condition of greatest
usefulness. The young cordillera with its mountains still in the making
can support only a scanty population, whereas the old eastern mountains,
with the lines of long life engraved upon every feature, open their arms
to man and let him live and prosper.

It is not enough that we should picture merely the four divisions of the
land of our continent. We must see how the land meets the sea. In low
latitudes in both the Old World and the New, the continents have tended
to emerge farther and farther from the sea during recent geological
times. Hence on the eastern side of both North and South America from
New Jersey to Brazil the ocean is bordered for the most part by coastal
plains, uplifted from the sea only a short time ago. On the mountainous
western side of both continents, however, the sea bottom shelves
downward so steeply that its emergence does not give rise to a plain
but merely to a steep slope on which lie a series of old beaches several
hundred and even one thousand feet above the present shore line. Such
conditions are not favorable to human progress. 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