421 



661°), the ridge of partition of Cochabamba 

 goes up towards the north-east, to 16° of lati- 

 tude, forming by the intersection of two planes 

 slightly inclined, one wall only amidst the sa- 

 vannahs, and separating the waters of the Gua- 

 pore, a tributary stream of the Madeira, from 

 those of the Aguapehy and Jauru, tributary 

 streams of the Rio Paraguay. This vast coun- 

 try between Santa Cruz de la Sierra, Villabella, 

 and Matbgrosso, is one of the most unknown 

 of South America. The two counter-forts of 

 Cordova and Salta present only a mountainous 

 territory * of small elevation, and which is 

 linked to the foot of the Andes of Chili. The 

 counter-fort of Cochabamba, on the contrary, 

 attains the limit of perpetual snows (2300 

 toises),and forms in some sort a lateral branch of 

 the Cordilleras, diverging even from their tops 

 between La Paz and Oruro. The mountains 

 composing this branch (Cordillera de Chirigua- 

 naes, de los Sauces and Yuracarees), stretch 

 regularly from west to east ; their eastern de- 



not taken from published maps j they are founded on com- 

 binations of astronomical geography of which the elements 

 will be found in the Analysis of my Atlas of South Ame- 

 rica. 



* I can scarcely believe that even the town of Jujuy is 

 650 toises above the level of the Ocean,, as Mr. Redhead 

 pretends in his book Sobre la dilatation del aire atmosfericOo 

 (Buenos Ayres, 181»,) p. 10. 



