15. Icefields and Glaciers
    Glaciers leave an impressive footprint on the landscape, carving the rock as they retreat and leaving behind steep topography and fiords where the ice once held sway
    http: //fs.fed.us/r10/tongass/forest_facts/reso...
    
    
16. NSIDC Education: Glaciers
    Learn about glaciers. Glaciers are made up of fallen snow that is compressed into a large, thickened mass of ice over many years. They form when snow remains in one location long enough to undergo the transformation into ice.
    http: //nsidc.org/cryosphere/index.html
    
    
17. The Retreat of Glaciers in the Midwestern U.S.
    Glaciers Maps,18,000 to 8,000 Years Ago
    http: //museum.state.il.us/exhibits/larson/glac...
    
    
18. Why Are Glaciers Blue?
    What causes the blue color that sometimes appears in snow and ice? As with water, this color is caused both by the absorption of red and yellow light...
    http: //webexhibits.org/causesofcolor/5C.html
    
    

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