Geologists are rapidly becoming convinced that the mammals spread from their central Asian point of origin largely because of great variations in climate.

The buffalo is a surprisingly stupid animal.

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

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.

Year by year we are learning that in this restless, strenuous American life of ours vacations are essential.

Geologists are rapidly becoming convinced that the mammals spread from their central Asian point of origin largely because of great variations in climate.

The whole history of life is a record of cycles.