THE ARGENTINE UPLANDS. 



359 



hill separates an affluent of the E,io Limay from the Chilian lake Picaullu (Lacar, 

 Ijajar), which stands about 2,400 feet above the sea, while the boquete de Perez 

 Kosalez, a third pass at the western extremity of Lake Nahuel-Huapi, falls below 

 2,800 feet. 



A second Argentine Cordillera, developed to the east of the first, is less ravined, 

 but also less elevated, though the peaks in the Sierras de Catalin and de las Angos- 



Fig. 1-17. — Nahuel-Hualpi and neighbouking Mountains. 

 Scale I : 1,200,000. 



fjChacabuco viejo 



West or Greenwich 



'■^ 



18 Miles. 



turas rise to 5,000 feet. This section of the Argentine orographic system had 

 also at one time its active volcanoes, like the frontier Cordillera farther west. The 

 Alumine, Mesa, and Chapel-co heights are all cones of Andésite, while scores of 

 other peaks flank both sides of the Rio Collon-cura. Their extinct craters are 

 now clothed with beech and myrtle groves ; but a cone near the sources of the 

 Biobio has laid all the surrounding districts under ashes. Here the traces of 



