Year By Year We Are Learning That

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.

Although Mountains May Guide Migrations, The Plains Are The Regions Where People Dwell In Greatest Numbers.

Year By Year We Are Learning That In This Restless, Strenuous American Life Of Ours Vacations Are Essential.

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.