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ical ages past. You will find the wind most actively at 

 work in arid regions and in those sections where sand 

 and dust most abound. 



A single experience in a wind storm must convince you 

 of the power as well as of the quantity of earth that is 

 moved throughout the world. Dust or particles of the 

 earth are in the air at all times, and with every drop of 

 rain, every flake of snow, and every movement in the air 

 these particles are carried elsewhere than to the spot at 

 which they were originally gathered up. You will find in 

 some sections of our country huge mounds or drifts of 

 sand that have been deposited by the constant and more 

 vigorous action of the wind. 



