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trees, and stones of considerable size may be lifted and 

 moved by a fierce wind storm. The wind-swept detritus 

 has been known even to obstruct and modify the course of 

 streams. Where the wind blows dust constantly in one 

 direction, deposits of great thickness are sometimes made. 



In Kansas and Nebraska there are beds of volcanic dust, 

 reaching in some places to a thickness of more than a score 

 of feet, and yet there are no known volcanoes either past 

 or present within hundreds of miles. In China there is a 

 deposit of fine, dustlike material, in some places a thousand 

 feet thick, which is thought by some to be wind blown. 

 This forms a very fertile and fine-textured soil and supports 

 a great population. Many of the inhabitants of the region 

 live in caves dug in the steep banks of the streams, so firm 

 and fine textured is the material. Wind deposits of this 

 kind are called loess beds. 



Ice as a Soil-builder. The agent that has had most to 

 do with preparing the soils of the great grain-bearing regions 

 of Russia, northern Europe, Canada, and the United States 

 is ice. It has worn down and pulverized the rocks into 

 soils, has mixed and transported the soils from regions 

 farther north, and has laid them down in the irregular 

 surfaces which form the fertile agricultural fields of these 

 regions at the present day. Ice has been the master soil- 

 builder of much of the tillable land of the world, and deserves 

 careful consideration. 



Snow in Winter. When the temperature of the air 

 falls below the freezing point, its moisture congeals into 

 little flake-like crystals and falls as snow. Where the 

 cold is continuous for a considerable time, the snow may 

 accumulate in deep layers over the ground. If the heat of 



