1 8 8 2 .] Geography and Travels. 1037 



:tenc wnere uie pny»i«-*u u,,,.,^ 



the advent of civilization have been so numerous or : 

 Not only has the fauna been in -r ■ : 



Si I merely has th 

 inches of annual rainfall increased, but it has als< 



>ated of by 

 , to find a 

 roduccd by 



tably extt 



xtent of country. The pro- 



gress 



xtended westward, is a most important fact. It may 

 be due in part to the planting of timber, but is probably much 

 more directly dependent on the immense acreage under wheat, 

 corn, and other crops, winch afford protection to the earth from 

 the sun's rays, and so check a too rapid evaporation. 



