Man could not stay there forever. He was bound to spread to new regions, partly because of his innate migratory tendency and partly because of Nature's stern urgency.

America forms the longest and straightest bone in the earth's skeleton.

As a matter of fact, an ordinary desert supports a much greater variety of plants than does either a forest or a prairie.

No part of the world can be truly understood without a knowledge of its garment of vegetation, for this determines not only the nature of the animal inhabitants but also the occupations of the majority of human beings.

Thus the races, though alike in their physical response to climate, may possibly be different in their mental response because they have approached America by different paths.

From first to last the civilization of America has been bound up with its physical environment.

Nevertheless most of the evergreen forests of the north must always remain the home of wild animals and trappers, a backward region in which it is easy for a great fur company to maintain a practical monopoly.