TRUE VOLCANOES. 277 



logical causal connection of the agreement, which is so often 

 manifested between the outlines of continents and the direc- 



Peru, Bolivia, Quito, and New Granada be connected with the mount- 

 ain chain of the Isthmus of Panama, and in this way with that of 

 Veragua and the series of volcanoes of Costa Rica and Central Amer- 

 ica in general. In my maps of 1816, 1827, and 1831, the mountain 

 svstems of which have been made more generally known by Brue in 

 Joaquin Acosta's fine map of New Granada (1817) and in other maps, 

 I have shown how the chain of the Andes undergoes a triple division 

 under the northern parallel of 2° 10' ; the western Cordillera running 

 between the valley of the Rio Cauca and the Rio Atrato ; the middle 

 one between the Cauca and the Rio Magdalena ; and the eastern one 

 between the valley of the Magdalena and the Llanos (plains), which 

 are watered by the affluents of the Maranon and Orinoco. I have 

 been able to indicate the special direction of these three Cordilleras 

 from a great number of points which fall in the series of astronomical 

 local determinations, of which I obtained 152 in South America alone 

 by culmination of stars. 



To the east of the Rio Dagua, and to the west of Cazeres, Rolda- 

 nilla, Toro, and Anserma, near Cartago, the western Cordillera runs 

 S.S.W. — N.N.E., as far as the Salto de San Antonio, in the Rio Cauca 

 (lat. 5° 11), which lies to the southwest of the Vega de Supia. Thence 

 as far as the Alto del Viento (Cordillera de Abibe, or Avidi, lat. 7° 12'), 

 9600 feet in height, the chain increases considerably in elevation and 

 bulk, and amalgamates, in the province of Antioquia, with the inter- 

 mediate or Central Cordillera. Farther to the north, toward the 

 sources of the Rios Lucio and Guacuba, the chain ceases, dividing into 

 ranges of hills. The Cordillera occidental, which is scarcely 32 miles 

 from the coast of the Pacific, near the mouth of the Dagua, in the 

 Bahia de San Buenaventura (lat. 3° 50'), is twice this distance in the 

 parallel of Quibdo, in the Choco (lat. 5° 48'). This observation is of 

 some importance, because we must not confound with the western 

 chain of the Andes the country with high hills, and the range of hills, 

 which in this province, so rich in gold dust, runs from south to north, 

 from Novita and Tado, along the right bank of the Rio San Juan and 

 the left bank of the great Rio Atrato. It is this inconsiderable series 

 of hills that is intersected in the Quebrada de la Raspadura by the 

 canal of Raspadura (Canal des Monches), which unites two rivers (the 

 Rio San Juan or Noanama and the Rio Quibdo, a tributary of the 

 Atrato), and by their means two oceans (Humboldt, Essai Politique, t. i., 

 p. 235) ; it was this, also, which was seen in the instructive expedition 

 of Captain Kellet between the Bahia de Cupica (lat. 6° 42'), long 

 and fruitlessly extolled by me, and the sources of the Napipi, which 

 falls into the Atrato. (See Humboldt, Op. cit., t. i., p. 231 ; and Rob- 

 ert Fitzrov, Considerations on the Great Isthmus of Central America in 

 the Journal of the Royal Geogr. Soc, vol. xx., 1851, p. 178, 180, and 

 186.) 



The middle chain of the Andes (Cordillera Central), constantly the 

 highest, reaching within the limit of perpetual snow, and, in its entire 

 extent, directed nearly from south to north, like the western chain, 

 commences about 35 miles to the northeast of Popayan with the Par- 

 amos of Guanacos, Huila, Iraca, and Chinche. Farther on toward 

 the north between Buga and Chaparral, rise the elongated ridge of the 



