1834. 



WATER DRAINAGE LAKE. 



353 



tance northward. At the place where we ceased to ascend the 

 stream, the Santa Cruz was almost as large as at the places 

 where we passed the first and second nights near the estuary. 

 The velocity of the current was still at least six knots an hour ; 

 though the depth remained undiminished. The temperature of 

 the water was 45°, while that of the air was seldom so high, 

 even in the day-time, and at night was usually below the freez- 

 ing point. Trees, or rather the trunks of trees, were found 

 lying upon the banks, whose water-worn appearance indicated 

 that they had been carried far by the stream. The water 

 was very free from sediment, though of a whitish blue colour, 

 which induces me to suppose that it has been chiefly produced 

 by melted snow, or that it has passed through lakes in which 

 the sediment it might have brought so far was deposited. 

 If filled from the waters of the nearer mountains only, its 

 temperature would surely be lower, approaching that of melted 

 snow : it would also, in all probability, bring much sediment, 

 and would therefore be muddier, and less pure in colour. 



When one considers how large an extent of country there is 

 between the River Negro and the Strait of Magalhaens, and 

 that through that extensive region only one river of magnitude 

 flows, it may be difficult to account for the manner in which 

 the drainage of the eastern side of the great Cordillera is car- 

 ried off, or where the melted snow and occasional heavy rains 

 disappear. 



The Gallegos is small, though it runs into a large estuary. 

 The Chupat river is very small : that at Port Desire is 

 scarcely more than a brook. At times, it is true, these smaller 

 rivers are flooded, but their floods (added to their usual streams) 

 seem unequal to carrying off the continual drainage of the 

 Andes. South of the Negro only the Santa Cruz flows with 

 a full and strong stream throughout the whole year, and my 

 idea is that the sources of the river Santa Cruz are not far 

 from those of the southern branch of the Neerro, near the 

 forty-fifth degree of latitude ; and that it runs at the foot of 

 the Andes, southward, through several lakes, until it turns to 

 the eastward in the parallel of fifty degrees. 



VOL. II. 2 A 



