8 STEPPES AND DESERTS. 



Cochabamba, and the Brazilian group of mountains, send 

 forth, between the province of Chiquitos and the isthmus 

 of Villabella, some detached spurs, which advance, as it 

 were, to meet each other. ( 14 ) A narrow plain connects 

 the forest lands of the Amazons with the Pampas of Buenos 

 Ayres. The latter far surpass the Llanos of Venezuela in 

 area ; and their extent is so great that while their northern 

 margin is bordered by palm trees, their southern extremity 

 is almost continually covered with ice. 



The Tuyu, which resembles the Cassowary (the Struthio 

 rhea), is peculiar to these Pampas, which are also the haunt 

 of troops of dogs ( 15 ) descended from those introduced by the 

 colonists, but which have become completely wild, dwelling 

 together in subterranean hollows, and often attacking with 

 blood-thirsty rage the human race whom their progenitors 

 served and defended. 



Like the greater portion of the desert of Sahara, ( 16 ) the 

 northernmost of the South American plains, the Llanos, are 

 in the torrid zone: during one half of the year they are 

 desolate, like the Lybian sandy waste ; during the other, 

 they appear as a grassy plain, resembling many of the Steppes 

 of Central Asia. (") 



It is a highly interesting though difficult task of general 

 geography to compare the natural conditions of distant 

 regions, and to represent by a few traits the results of this 

 comparison. The causes which lessen both heat and dry- 

 ness in the New World ( 18 ) are manifold, and in some 

 respects as yet only partially understood. Amongst these 

 may be classed the narrowness and deep indentation of the 



