for preservation. The fossils found in the rocks
of the earth's crust support this view. They indicate that most of the
great families of higher animals originated in the central part of the
great land mass of Europe and Asia. A second but much smaller area of
evolution was situated in the similar part of North America. From these
two centers new forms of life spread outward to other continents. Their
movements were helped by the fact that the tetrahedral form of the earth
causes almost all the continents to be united by bridges of land.

* Unpublished manuscript.

If any one doubts the importance of the tetrahedral form, let him
consider how evolution would have been hampered if the land of the globe
were arranged as isolated masses in low latitudes, while oceans took
the place of the present northern continents. The backwardness of the
indigenous life of Africa shows how an equatorial position retards
evolution. The still more marked backwardness of Australia with its
kangaroos and duck-billed platypuses shows how much greater is the
retardation when a continent is also small and isolated. Today, no less
than in the past, the tetrahedral form of the earth and the relation of
the tetrahedron to the poles and to the equator preserve the conditions
that favor rapid evolution. They are the dominant factors in determining
that America shall be one of the two great centers of civilization.

If North and South America be counted as one major land mass, and
Europe, Asia, and Africa as another, the two present the same general
features. Yet their mountains, plains, and coastal indentations are so
arranged that what is on the east in one is on the west in the other.
Their similarity is somewhat like that of a man's two hands placed palms
down on a table.

On a map of the world place a finger of one hand on the western end of
Alaska and a finger of the other on the northeastern tip of Asia and
follow the main bones of the two continents. See how the chief mountain
systems, the Pacific "cordilleras," trend away from one another,
southeastward and southwestward. In the centers of the continents they
expand into vast plateaus. That of America in the Rocky Mountain region
of the United States reaches a width of over a thousand miles,
while that of Asia in Tibet and western China expands to far greater
proportions.

From the plateaus the two cordilleras swing abruptly Atlantic-ward. The
Eurasian cordillera extends throu