HOW IS SOIL MADE? 



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The Chisana Glacier, Alaska. Glaciers carry with them ground-up rocks and stones, 



which may be deposited far from where they were eroded. Explain the meaning 



of the dark line running up the right-hand side of this glacier. 



recent, underground waters may be heated by beds of 

 lava which are still hot. Here we find hot springs. If 

 the water, instead of flowing regularly, is erupted inter- 

 mittently, the spring is called a geyser. Since hot water 

 dissolves mineral matter more readily than cold water, 

 much matter is brought by hot springs to the surface 

 and deposited as the water cools. Hot springs are found 

 in several parts of the world, most of them being in 

 Yellowstone National Park. Here there are about 3000 

 geysers, of which Old Faithful deserves its name, for it 

 erupts about once every hour, when it throws up about 

 700,000 gallons of water. 



Erosion by Glaciers. A great ice sheet covers Green- 

 land today. The pressure from the continued accumu- 

 lation of snow causes a slow movement of this vast sheet 

 of ice into the ocean, and from time to time fragments on 

 the edges break off and form icebergs. It is believed 

 that many thousands of years ago a great sheet of ice 

 moved down from the north and covered a large part of 



