SWARM OP LOCUSTS. 81 



the distance of only ten or fifteen miles from the 

 outer range of the Cordillera, we did not cross a 

 single stream. In many parts the ground was in- 

 crusted with a saline efflorescence ; hence we had 

 the same salt- loving plants which are common near 

 Bahia Blanca. The landscape has a uniform char- 

 acter from the Strait of Magellan along the whole 

 eastern coast of Patagonia to the Rio Colorado ; 

 and it appears that the same kind of country ex- 

 tends inland from this river in a sweeping line as 

 far as San Luis, and perhaps even further north. 

 To the eastward of this curved line lies tlie basin 

 of the comparatively damp and green plains of 

 Buenos Ayres. The sterile plains of Mendoza and 

 Patagonia consist of a bed of shingle, worn smooth 

 and accumulated by the waves of the sea, while 

 the Pampas, covered by thistles, clover, and grass, 

 have been formed hy the ancient estuary mud of 

 the Plata. 



After our two day's tedious journey, it was re- 

 freshing to see in the distance rows of poplars and 

 willows growing round the village and river of Lux- 

 an. Shortly before arriving at this place we observ- 

 ed to the south a ragged cloud of a dark, reddish- 

 brown colour. At first we thought that it was 

 smoke from some great fire on the plains ; but we 

 soon found that it was a swarm of locusts. They 

 were flying northward ; and, with the aid of a light 

 breeze, they overtook us at the rate often or fifteen 

 miles an hour. The main body filled the air from 

 a height of twenty feet, to that, as it appeared, of 

 two or three thousand above the ground ; " and the 

 sound of their wings was as the sound of chariots of 

 many horses running to battle :" or rather, I should 

 say, like a strong breeze passing through the rig- 

 ging of a ship. The sky, seen through the advanced 

 guard, appeared like a mezzotinto engraving, but 

 IT. 6 



