348 



CHARLES DARWIN 



March 25th. — I was reminded of the Pampas of Buenos 

 Ayres, by seeing the disk of the rising sun, intersected by an 

 horizon level as that of the ocean. During the night a heavy 

 dew fell, a circumstance which we did not experience within 

 the Cordillera. The road proceeded for some distance due 

 east across a low swamp; then meeting the dry plain, it 

 turned to the north towards Mendoza. The distance is two 

 very long days' journey. Our first day's journey was called 

 fourteen leagues to Estacado, and the second seventeen to 

 Luxan, near Mendoza. The whole distance is over a level 

 desert plain, with not more than two or three houses. The 

 sun was exceedingly powerful, and the ride devoid of all 

 interest. There is very little water in this " traversia," and 

 in our second day's journey we found only one little pool. 

 Little water flows from the mountains, and it soon becomes 

 absorbed by the dry and porous soil; so that, although we 

 travelled at 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 incrusted with a 

 saline efflorescence; hence we had the same salt-loving 

 plants which are common near Bahia Blanca. The land- 

 scape has a uniform character from the Strait of Magellan, 

 along the whole eastern coast of Patagonia, to the Rio Colo- 

 rado; and it appears that the same kind of country extends 

 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 the basin of the comparatively damp and 

 green plains of Buenos Ayres. The sterile plains of Men- 

 doza 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 by 

 the ancient estuary mud of the Plata. 



After our two days' tedious journey, it was refreshing to 

 see in the distance the rows of poplars and willows growing 

 round the village and river of Luxan. Shortly before we 

 arrived at this place, we observed to the south a ragged cloud 

 of 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 



