THE ARGENTINE UPLANDS. 355 



Hauthal discovered two lakes, evidently of glacial origin, dammed up by a barrier 

 of frontal moraines. 



The Nevado de Faraatina, which rises over 125 miles to the south-west of 

 Aconquija, resembles this mass in its imposing aspect, especially when seen from 

 its southern slopes. But, unlike Aconquija, it is not completely detached from 

 the Andean plateau, with which it is still connected by a ridge of heights disposed 

 in a line with the main axis of the system. According to Naranjo, by whom it 

 has been ascended, Famatina overtops Aconquija, being 20,680 feet high, and even 

 appearing much higher relatively to the surrounding plains, which here fall to 

 from 3,000 to 4,500 feet above sea-level. 



Granites and porphyries form the framework of the range, the lateral rocks 

 consisting of white, red, and black raetamorphic schists. In the direction of the 

 south it is continued by a chain, which gradually diminishes in height, and at 

 last merges in the region of saline depressions. This chain may be regarded as 

 belonging to the same system of low ridges and hills which follow in lines parallel 

 with the main crests of the Cordilleras. Such are the Sierra de Chaves, and the 

 equally isolated Pie de Palo, east of the city of San Juan. 



Eastern and Western Cordilleras. 



West of the Nevado de Famatina the contracted Andean plateau is decom- 

 posed into two parallel Cordilleras of about equal height, but contrasting in the 

 character of their rocks. The western Cordillera forms the water-parting of the 

 two slopes, as well as the political frontier between Chili and Argentina. The 

 eastern, lying entirely within the Argentine State, is carved into fragments by 

 the torrents piercing it at intervals, and carrying the detritus down to the plains. 

 While the former, of much more recent origin, consists of mesozoic formations 

 with later eruptive rocks cropping out here and there, the " ante-cordillera," or 

 " pre-cordillera," as the eastern range is called, is formed of granites, porphyries, 

 and paleozoic strata. 



This outer chain was evidently the original backbone, and its decomposition 

 had already set in before the Argento-Chilian frontier- range appeared above the 

 surface. The whole of these uplands presents a certain resemblance to the equa- 

 torial Andes, which are sirailarlj^ divided into two parallel chains, the western 

 nearly continuous, tbe eastern broken into seven sections by the headstreams of 

 the Amazons, and regarded by Whymper less as a mountain range than a succes- 

 sion of groups without natural cohesion. 



At the point where Famatina is rooted in the plateau, the two Cordilleras are 

 not yet developed into distinct chains. Here the snowy peaks of Bonete, Veladero, 

 and la Gallina Muerta rise in isolated grandeur to the relative heights of from 

 3,500 to 5,000 feet above the broad pedestal between the Chilian and Argentine 

 slopes. This elevated plain stands itself at a mean altitude of from 13,000 to 

 14,500 feet above sea-level, and stretches away in gentle undulations beyond the 

 horizon. On these bleak expanses the wind often blows with great fury, and is 



