The structure of the Cordillera of the Andes, that is, its division into several chains nearly parallel, which are again joined by knots of mountains, is very remarkable. On our maps this structure is indicated but imperfectly; and what La Condamine and Bouguer merely guessed, during their long visit to the table-land of Quito, has been generalized and ill-interpreted by those who have described the whole chain according to the type of the equatorial Andes. The following is the most accurate information I could collect by my own researches and an active correspondence of twenty years with the inhabitants of Spanish America. The group of islands called Tierra del Fuego, in which the chain of the Andes begins, is a plain extending from Cape Espiritu Santo as far as the canal of San Sebastian. The country on the west of this canal, between Cape San Valentino and Cape Pilares, is bristled with granitic mountains covered (from the Morro de San Agueda to Cabo Redondo) with calcareous shells. Navigators have greatly exaggerated the height of the mountains of Tierra del Fuego, among which there appears to be a volcano still burning. M. de Churruca found the height of the western peak of Cape Pilares (latitude 52 degrees 45 minutes south) only 218 toises; even Cape Horn is probably not more than 500 toises* high. (* It is very distinctly seen at the distance of 60 miles, which, without calculating the effects of terrestrial refraction, would give it a height of 498 toises.) The plain extends on the northern shore of the Straits of Magellan, from the Virgin's Cape to Cabo Negro; at the latter the Cordilleras rise abruptly, and fill the whole space as far as Cape Victoria (latitude 52 degrees 22 minutes). The region between Cape Horn and the southern extremity of the continent somewhat resembles the origin of the Pyrenees between Cape Creux (near the gulf of Rosas) and the Col des Perdus. The height of the Patagonian chain is not known; it appears, however, that no summit south of the parallel of 48 degrees attains the elevation of the Canigou (1430 toises) which is near the eastern extremity of the Pyrenees. In that southern country, where the summers are so cold and short, the limit of eternal snow must lower at least as much as in the northern hemisphere, in Norway, in latitude 63 and 64 degrees; consequently below 800 toises. The great breadth, therefore, of the band of snow that envelopes these Patagonian summits, does not justify the idea which travellers form of their height in 40 degrees south latitude. As we advance towards the island of Chiloe, the Cordilleras draw near the coast; and the archipelago of Chonos or Huaytecas appears like the vestiges of an immense group of mountains overwhelmed by water. Narrow estuaries fill the lower valleys of the Andes, and remind us of the fjords of Norway and Greenland. We there find, running from south to north, the Nevados de Maca (latitude 45 degrees 19 minutes), of Cuptano (latitude 44