Introduction 11 



having an occasional overflow into Lake Manitoba; it abounds 

 in jackfish and sticklebacks. 



A remarkable circumstance about these lakes is the fact 

 that they grow larger and deeper, for a time, then gradually 

 shrink. That is to say, the general level of water in the whole 

 Province, rises and falls in a cycle of years. Just what the 

 period of years is has not been determined. In 1882 at Car- 

 berry the water was high, but falhng; in 1884 it was much 

 lower; 1892 was a year of very low water; in 1904 it was very 

 high. The explanation is unknown to me. 



Forests and Prairies. 



Four-fifths of Manitoba is in the forest region. The true 

 Prairies are found only in the south-western quarter of our 

 country; and this is so much varied by tracts of hills and 

 wooded river-valleys, occupying fully one-quarter of the area, 

 that the prairies themselves do not aggregate more than one- 

 sixth of the entire province. 



The map showing the distribution of timber I compiled 

 in 1890, from personal observations, assisted by Reports of the 

 Dominion Geographical and Geological Survey, and the 

 Reports of the United States Tenth Census. In 1905 I found 

 that though much good timber had been cut, there was no very 

 material change in the boundaries of the tracts formerly 

 classed as wooded country. 



There can be no doubt that in past ages large areas were 

 denuded of trees and turned into prairies, by wild-fire; but 

 this agency has become inoperative. The true Plains were 

 treeless from other causes. 



The Faunal Areas and Life Zones of Canada/ 



By far the most important factor in the distribution of 

 life is temperature. 



The grand temperature point in nature, the one at which 



' This is founded chiefly on Dr. J. A. Allen's Natural Provinces of the North 

 American Temperate Region, 1871, his Geographical Distribution of the Mammals 



