LAKES AND EIVERS OF PATAGONIA. 387 



One of these basins, discovered by Moreno in 1877, and by him named tbe San 

 Martin in honour of the Conqueror of Chacabuco, develops an irregular oval 

 between lofty mountains of volcanic origin, whence descend glaciers and ava- 

 lanches. East of this basin meres and hi goons occupy a deep trough dominated 

 by the pyramidal Mount Kochait, " Bird," and other volcanoes. Towards the 

 west these lacustrine depressions send their overflow to a still unexplored basin 

 at the east foot of the Fitzroy volcano, which in its turn discharges into Lake 

 Viedma, so named from xVntonio de Viedma, who discovered it in 1782. 



L.AKES YiEDMA AND ArGENTIXO. 



Viedma, largest of all the basins in these sub-Andean regions, stretches 

 a distance of about 50 miles in the direction from north-west to south-east. 

 It is swept by fierce gales which raise huge waves like Atlantic billows, 

 and on the west side a large glacier discharges great blocks, which float away 

 in long processions towards the east side where they are stranded, and strew 

 the shores with erratic boulders. Trac'es of ancient beaches show that the lake 

 stood formerly at a much higher level than at present. Its waters have been 

 carried off by the Rio Leona (Orr), which winds through a mountain gorge 

 southwards, and to Lake Argentino, which it enters at its north-east corner. A 

 now dry channel formerly carried the waters of the Rio Leona directly to the 

 Rio Santa Cruz. 



Lake Argentino, which was discovered by Gardiner in 1868, and afterwards 

 visited by Feilberg in 1873, and navigated by Moreno in 1878, occupies that region 

 to which Fitzroy and Darwin gave the name of the " Mj^sterious Plain." They even 

 sighted and named two mountains, Hobler Hill and Castle Hill, which are bathed 

 by its waters, without recognising the lake itself. At present the basin stands, 

 according to Carlos Burmeister, at an elevation of 1,050 feet, but like Viedma, 

 it formerly stood at a mUch higher level, and the traces of two ancient beaches 

 may still be clearly followed above its present margin. Like those of the Swiss 

 Alps, the lakes of the Argentine Andes appear to be extremely deep. Two miles 

 from the shore Moreno failed to reach the bottom of Argentine with a soundina:- 

 line 122 feet long. They were originally perhaps fiords, like those on the opposite 

 side of the Andes, and like them they have their deepest parts at the foot of the 

 mountains, whence they shoal gradually seawards. 



The Santa Cruz and Ciiico Rivers. 



The Rio Santa Cruz, outlet of the chain of lakes which begin with Viedma, 

 escapes from the east side of Lake Argentino a few miles below the mouth of the 

 Rio Leona. The current is interrupted by rapids, which are impassable by boats, 

 which have to be drawn up by ropes. But when the river is in flood, light craft 



