Introduction 13 



2 The Arctic Region. 



Similarly, the south boundary of the Arctic Region is 

 virtually the Arctic Circle (N. Lat. 66i°), which is the south 

 limit of day without night in mid-summer; and night without 

 day in mid-winter, that is, the land of the midnight sun; and 

 this would be the exact south boundary of the Arctic Region, 

 but that in America the cold currents of Hudson's Bay, etc., and 

 the warm currents of the Mackenzie and Yukon, etc., have 

 bent the line southward and northward as indicated. 



This is the land of long, cold winters and short, mild sum- 

 mers, the country where frost never leaves the soil. It is a 

 region without trees, the home of the White Bear, the White 

 Fox, the Polar White Hare, the White Lemming, white owl, 

 and the snowbird. 



And whether considered in the far north, or on the moun- 

 tain tops which form Arctic islands in the warmer regions, its 

 south or lower boundary is the best-marked faunal line in 

 America. 



3 The Temperate Region. 



Lying between these two takes in the United States and 

 the greater part of Canada. Its north line is the limit of trees, 

 Its south line the limit of frost. This is the region of long, bright 

 summer, and of short, cold winter that comes with frost and 

 snow. This is the range of deciduous trees, as well as of 

 pines and spruces, the land of corn and wine, the proper home 

 of the agricultural white man. 



Canada is concerned only with the Arctic and Temper- 

 ate Regions. Each of these regions is divisible into several 

 Life-zones, which theoretically extend east and west across the 

 continent. 



These also are bounded on the north and on the south 

 chiefly by the lines of temperature. Concerning these limits 

 Merriam says: "Investigations conducted by the Biological 

 Survey have shown that the northern distribution of terrestrial 

 animals and plants is governed by the sum of the positive 

 temperatures for the entire season of growth and reproduction. 



