GLACIER 



2500 



GLACIER 



surface of the land. Hills were leveled, lake 

 beds were filled up in some places and scooped 

 out in others. Great masses of rock and gravel 

 were carried by the glaciers and deposited along 

 its course, forming drift. In some places in 

 the states south of the Great Lakes this drift 

 forms ranges of low hills from 200 to 250 feet 

 high. 



The fine silt deposited on the prairies of 

 the Mississippi Valley and constituting the 

 fertile soil of this region was also another re- 

 sult of this movement. In some localities the 

 rocks were stripped bare of soil, and their sur- 

 faces were polished and marked. Lakes were 

 formed in regions where they had not been 

 before, and in other regions lakes were drained 

 by having their outlets lowered. The fertile 

 regions in the lowlands of Europe were formed 

 in the same way. 



Life. In parts of North America the mam- 

 moth, the mastodon, the glyptodon, the woolly 

 rhinoceros and other large animals^ roamed 

 over the land. (These animals are described 



in this set of books.) Similar animals, if not 

 the same, were found in Europe. In South 

 America there were numerous gigantic sloths. 

 There is no evidence that man lived in Amer- 

 ica, but some geologists think that he lived 

 in -Europe during the period. Both plant and 

 animal life changed its habitat with the change 

 of climate. Many present conditions can be ex- 

 plained only by reference to the Glacial Period. 

 Causes. Many theories have been advanced 

 to account for the Glacial Period, but none is 

 satisfactory. The following are those most gen- 

 erally advanced: (a) that a sudden elevation 

 of the northern continents caused a fall in 

 temperature; (b) that a change in atmospheric 

 and oceanic currents caused such heavy rain- 

 fall as to cause the glaciers; (c) that the Period 

 was due to a relative change in position of the 

 earth and sun. See GEOLOGY; MORAINE; GLA- 

 CIER. W.F.R. i 



Consult Dawson's Canadian Ice Age; Wright's 

 Ice Age in North America; Bonney's Ice Work, 

 Past and Present. 



THE STORY OF GLACIERS 



LACIER, gla'shcr. Imagine a great 

 river stretching from near the summit of a 

 lofty mountain down its sides for thousands of 

 feet a river, not of hurrying, sparkling, limpid 

 water, but of solid ice, with a movement so 

 slow that its pace is measured in inches per 

 day rather than in miles per hour. 



Some of the snow which falls high up on the 

 mountains is lost by evaporation; in certain 

 altitudes some is melted and in the form of 

 streams begins to run through ruts and gullies 

 flown the mountain sides. However, most of 

 this escaping water soon freezes into a long, 

 solid river of ice, and when thick enough be- 

 gins by its great weight to move in a mass 

 very slowly down towards the valleys. This 

 slow movement, usually less than two feet a 

 day, continues until a point in its descent is 

 reached when evaporation and melting offset 

 the supply from higher regions. At this point 

 the glacier proper ends and rivers begin, if 

 the location is inland. If the end of the 



glacier is at the sea, great masses of glacial 

 ice may break off and drop into the sea and 

 become icebergs. Such, in brief, is the word 

 picture which may be drawn of this majestic, 

 awe-inspiring spectacle. 



Glaciers are always formed wherever more 

 snow falls than melts during the year; conse- 

 quently they are found in cold climates like 

 those of the polar regions and on the sum- 

 mits and slopes of high mountains in the tem- 

 perate and. tropical latitudes. The best-known 

 glaciers are those of the Alps in Europe and 

 those of the Rocky Mountains in the United 

 States, Canada and Alaska. They are also 

 found in the Scandinavian Peninsula, in the 

 Andes and the Himalaya Mountains; on 

 Greenland and other islands in the Arctic 

 Ocean and on the Southern Alps in New 

 Zealand. 



In North America the largest glaciers are 

 found on the shores of Glacier Bay and around 

 Mount Fairweather in Alaska. There are also 



