THE ARCTIC LANDS. 



33 



tinuous belt, stretching through three parts of the world, in a breadth of from 

 15° to 20°, even the woods of the Amazon, which cover a surface fifteen times 

 greater than that of the United Kingdom, shrink into comparative insignifi- 

 cance. Unlike the tropical forests, which are characterized by an immense 

 variety of trees, these northern woods are almost entirely composed of conif- 

 era3, and one single kind of fir or pine often covers an immense extent of 



