GLACIAL PERIOD 



2499 



GLACIAL PERIOD 



and the town has a Marconi wireless station, 

 said to be the most powerful in the world, up 

 to 1917. Population in 1901, 6,945; in 1911, 

 16,562. A.H.MC K. 



.GLACIAL, gla'shal, PERIOD, or AGE OF 

 ICE. Boys and girls who live anywhere in 

 Canada or in almost any part of the Northern 

 United States can hardly believe that once, 

 even though it -was thousands upon thousands 

 of years ago, their home land was covered 

 with a vast sheet of ice. As they look about 

 them on forests and streams and fields aglow 



The chief characteristic of the Glacial Period 

 was the great ice sheet, which covered over 

 8,000,000 square miles of the earth's surface. 

 Fully one-half of this ice-covered area was in 

 North America. With the exception of most 

 of Alaska all the northern part of the conti- 

 nent, including all of Canada, was enveloped in 

 ice. The southern boundary of the ice field 

 was marked by the Ohio and the Missouri 

 rivers. In the east the ice sheet included all 

 New England, New York, the northern part 

 of Pennsylvania, and west of the Appalachian 

 Mountains all the states of the great Missis- 

 sippi Valley as far south as the Ohio River. 

 All of Minnesota, most of North Dakota, the 

 northern part of Montana and Washington and 

 all of Iowa, the eastern parts of South Dakota 

 and Nebraska, with a small portion of Kansas, 

 and more than half of Missouri were also in- 

 cluded. 



Movement. In Europe the Scandinavian 

 Peninsula, all the lowlands of Belgium, Ger- 



IN NORTH AMERICA 



IN EUROPE 



The solid line at the southern extremity of the glacier fields represents roughly the limits of 

 glaciation. 



with beauty their minds can scarcely picture so 

 cold and forbidding a scene as a vast ice mass, 

 over two thousand miles long and half as 

 wide, where now millions of happy people live. 

 When it is realized that in places the ice 

 sheet was supposed to have been as much as 

 a mile, and possibly more, in thickness, the 

 fact seems the more astounding. 



The scientific men who tell of this strange 

 age agree that this so-called Glacial Period 

 was that period in the formation of the world 

 in which the change was made from the most 

 recent past to the present era. For this 

 reason the Glacial is also called the Pleistocene 

 Period, a term derived from two Greek words 

 meaning the most recent period back of the 

 Age of Man. 



many, Denmark, Holland and Russia were un- 

 der ice. The glaciers of the Alps extended 

 much lower than at present, and a good por- 

 tion of the British Isles was covered with 

 glaciers. Ice sheets of smaller areas existed 

 in Asia and South America. In North America 

 this great ice sheet gathered around three cen- 

 ters: one in Labrador, east of Hudson Bay; 

 the Keewatin center, west of Hudson Bay; and 

 the Cordilleran center, east of the Rocky 

 Mountains in Canada. 



In the course of time the glaciers began to 

 move from the three centers. In each case the 

 movement was toward the lowest level, hence 

 from each center the motion was in nearly all 

 directions. Such was the power of the great 

 mass of ice that it very naturally changed the 



