CHAPTEE XV. 



THE NEARCTIC REGION. 



THIS region consists almost wholly of Temperate North America 

 as denned by physical geographers. In- area it is about equal 

 to the Neotropical region. It possesses a vast mountain range 

 traversing its entire length from north to south, comparable 

 with, and in fact a continuation o the Andes, and a smaller 

 range near the east coast, equally comparable with the mountains 

 of Brazil and Guiana. These mountains supply its great river- 

 system of the Mississippi, second only to that of the Amazon ; 

 and in its vast group of fresh-water lakes or inland seas, it 

 possesses a feature unmatched by any other region, except 

 perhaps by the Ethiopian. It possesses every variety of climate 

 between arctic and tropical ; extensive forests and vast- prairies ; 

 a greatly varied surface and a rich and beautiful flora. But these 

 great advantages are. somewhat neutralized by other physical 

 features. It extends far towards the north, and there it reaches 

 its greatest width ; while in its southern and warmest portion it 

 suddenly narrows. The northern mass of land causes its 

 isothermal lines to bend southwards ; and its winter tempera- 

 ture especially, is far lower than at corresponding latitudes 

 in Europe. This diminishes the available area for supporting 

 animal life ; the amount and character of which must be, to a 

 great extent, determined by the nature of the least favourable 

 part of the year. Again, owing to the position of its mountain 

 ranges and the direction of prevalent winds, a large extent of its 

 interior, east of the Eocky Mountains, is bare and arid, and often 

 almost desert ; while the most favoured districts, those east of 



