PAMPAS. 



265 



Nearly the whole of this enormous district 

 is composed of a rich alluvial soil, in which 

 not a stone is to be found. The thistles grow 

 so rapidly in the spring, that before the 

 summer is over, they are ten feet high, and 

 with such thick stems that Captain Head 

 thought an army would be stopped by them 

 in its march, at that time of year. Their 

 decay is quite as rapid, and the clover is 

 then to be seen bursting over the dried up and 

 fallen thistle, until the whole face of the 

 country is changed. 



Numerous rivers, some of which I have men- 

 tioned, gently pursue their silent course along 

 these flat plains, having lost all the character 

 of the torrents which 'gave them birth in the 

 Andes. The Rio Tercero, and Quinto, and 

 the Desaguadero and Tunuyan, are the principal. 

 The Tercero is the only river which, taking 



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