THE SHAPE OF THE EARTH 



19 



were immeasurable. The lofty mountains and broad 

 oceans are barriers which plants and animals have tried in 

 vain to cross and which man himself has had difficulty in 

 surmounting. 



THE HIMALAYA MOUNTAINS. 

 An insurmountable barrier in central Asia. 



These regions have furnished protected spaces to differ- 

 ent species of plants, groups of animals, communities of 

 men, and unmolested in these protected places they have 

 developed their peculiar characteristics. Where man has 

 not succeeded in thoroughly overcoming the barrier, se- 



