CHARACTER OF THE STEPPES. 223 



foot of the Andes of Pasto, and frequently not encounter an eminence 

 a foot high in 270 square miles. Their length is twice that of their 

 breadth ; and as the wind blows constantly from the east, the climate 

 is the more ardent the further west. " These Steppes, for the most 

 part," says Mrs. Somerville,* " are destitute of trees or bushes, yet 

 in some places they are dotted with the mauritia and other palms." 

 Flat as they are, two kinds of inequalities will sometimes occur : one 

 consists of banks or shoals of grit or compact limestone, five or six 

 feet high, perfectly level for several leagues, and imperceptible except 

 on their edges; the other inequality can only be detected by the 

 barometer or levelling instruments ; it is called a Mesa, and is a 

 gentle knoll swelling very gradually to an elevation of a few fathoms. 

 Yet slight as is this altitude; a Mesa forms the watershed from south- 

 west to north-east, between the affluents of the Orinoco and the 

 streams flowing to the northern coast of Terra Firma. In the wet 

 season, from April to the end of October, the tropical rains pour down 

 in torrents, and hundreds of square miles of the Llanos are inundated 

 by the overflow of the rivers. In the hollows the water is sometimes 

 twelve feet deep, and such numbers of horses and other animals 

 perish, that the ground smells strongly of musk, an odour peculiar to 

 many quadrupeds. " From the flatness of the country, too, the 

 waters of some affluents of the Orinoco are driven backwards by the 

 floods of that river, especially when aided by the wind, and form 

 temporary lakes. When the waters subside, these Steppes, manured by 

 the sediment, are mantled with verdure, and produce ananas, while 

 occasional groups of fan palm-trees and mimosas skirt the rivers. 

 When the dry weather returns, the grass is burnt to powder ; the air 

 is filled with dust raised by currents occasioned by difference of tem- 

 perature, even when there is no wind. If by any accident a spark of fire 

 falls on the scorched plains, a conflagration spreads from river to river, 

 destroying every animal, and leaves the clayey soil sterile for years, 

 till vicissitudes of weather crumble the brick-like surface into earth." 

 When this takes place, the rending of the indurated soil is sudden 

 * Mrs. Somerville, " Physical Geography," i. 79. 



