These minor ranges, excepting the Zenta, are separated from the Andean masses by comparatively low depressions and are usually described as distinct ranges; topographically, however, they seem to form a continuation of the ranges running southward from the Santa Victoria and forming the eastern rampart of the great central plateau of which the Puna de Atacama covers a large part.
Above sea-level, where it is crossed by a railway; north-east is another extensive saline basin enclosing the " Mar Chiquita " (of Cordoba) and the morasses into which the waters of the Rio Saladillo disappear; and on the north are the more elevated plains, partly saline, of western Cordoba, which separate this isolated group of mountains from the Andean spurs of Rioja and San Luis.
Some of the principal affluents are the Vinchina and Jachal, or Zanjon, which flow into the Vermejo, the Patos, which flows into the San Juan, and the Mendoza, Tunuyan and Diamante which flow into the Desaguadero, all of these being Andean snow-fed rivers.
In the extreme north-west an elevated region, whose aridity is caused by the " blanketing " influence of the eastern Andean ranges, extends.
Below this region, where the Andean barrier is low and broken, the moist westerly winds sweep over the land freely and give it a large rainfall, good pastures and a vigorous forest growth.
In the Andean region, a dry, hot wind from the north or north-west, called the Zonda, blows with great intensity, especially in September - October, and causes much discomfort and suffering.
The greater part of Patagonia is comparatively barren and has no arboreal growth, except in the well-watered valleys of the Andean foothills.
Not only has scientific study advanced at the university of Buenos Aires, but scientific research is promoting the development of the country; examples are the geographical explorations of the Andean frontier, and especially of the Patagonian Andes, by Francisco P. Moreno.
The creation of a commercial port at Bahia Blanca and the development of the territories of La Pampa, Rio Negro and Neuquen, have given an impetus to railway construction in that region, and new lines are being extended toward the promising districts among the Andean foothills.
In the Andean provinces of Mendoza, San Juan, Catamarca and Rioja viticulture attracts much attention, and the area in vineyards in 1901 was 109,546 acres, only 18% of which was outside the four provinces named.
Taking, however, the Andean flora as typical, it contains a very marked endemic element; Ball finds that half the genera and four-fifths of the species are limited to it; on the other hand, that half the species of Gamopetalae belong to cosmopolitan genera such as Valeriana, Gentiana, Bartsia and Gnaphalium.
Compositae compose a quarter of the Andean flora, which is a greater proportion than in any in the world.
These rivers have no tributaries of importance within the territory, but the Limay receives some small streams from the Andean slopes.
The largest of a group of beautiful lakes in the higher Andean valleys is the celebrated NahuelHuapi (Lion Grass), which is nearly 50 m.
The temperature of the Andean region is cold even in summer, but on the lower plains it is hot in summer, and only moderately cold in winter.
Its greatest tributary is the Cachapoal, in the valley of which, among the Andean foothills, are the popular thermal mineral baths of Cauquenes, 2306 ft.
The result was of importance, as it was known that Brazil was on friendly terms with Chile, and this interchange of courtesies had some effect in bringing about a settlement of the controversy between Chile and Argentina over the Andean frontier question without recourse to hostilities.
The rocks of Falcon are believed by Sievers to belong to the Andean system; while the outlying peninsula of Paraguana probably belongs, geologically, to the same massif as Goajira and the Sierra Nevada de Santa Maria in Colombia.
Railway construction in Peru began in 1848 with a short line from Callao to Lima, but the building of railway lines across the desert to the inland towns of the fertile river valleys and the Andean foot-hills did not begin until twenty years later.
Coca (Erythroxylon coca) is a product peculiar to the eastern Andean slopes of Bolivia and Peru, where it has long been cultivated for its leaves.
The rearing of these animals requires much patience and skill, in which no one has been able to match the Indian breeders of the Andean plateaus.
Immediately following the Spanish invasion the Andean region was thoroughly explored, and with the assistance of Indian slaves thousands of mines were opened, many of them failures, some of them becoming famous.
Practically the whole Andean region of Peru is mineral-bearinga region 1500 m.
By Chile, from which it is separated by the Andean Cordilleras.
The chief points of correspondence between these two great land masses, besides the southward tapering, are as follows: - (i) The areas of ancient fundamental rocks of the north-east (Laurentian highlands of North America, uplands of Guiana in South America), which have remained without significant deformation, although suffering various oscillations of level, since ancient geological times; (2) the highlands of the southeast (Appalachians and Brazilian highlands) with a north-east south-west crystalline axis near the ocean, followed by a belt of deformed and metamorphosed early Palaeozoic strata, and adjoined farther inland by a dissected plateau of nearly horizontal later Palaeozoic formations - all greatly denuded since the ancient deformation of the mountain axis, and seeming to owe their present altitude to broad uplifts of comparatively modern geological date; (3) the complex of younger mountains along the western side of the continents (Western highlands, or Cordilleras, of North America; Andean Cordilleras of South America) of geologically modern deformation and upheaval, with enclosed basins and abundant volcanic action, but each a system in itself, disconnected and not standing in alignment; (4) confluent lower lands between the highlands, giving river drainage to the north (Mackenzie, Orinoco), east (St Lawrence, Amazon), and south (Mississippi, La Plata).
The former, which rises in the Sierra de Merida, which overlooks the Lake of Maracaibo, has 16 large affluents; the latter has its sources near the Colombian city of Pamplona, and they are only separated from the basin of the river Magdalena by the "Oriental" Andean range.
The Meta is known as such from the union of two Andean streams,.
The Andean slopes cover a considerable part of its territory, and in the W.
Though of great interest to scientific investigators because of this unceasing activity, and of its peculiar position in the Andean system, and because of the difficult and dangerous country by which it is surrounded, Sangay has been but rarely visited by European travellers.
The Napo and its tributaries are celebrated in the early history of South America as the route by which Gonzalo Pizarro and Oreliana first reached the Amazon, and it was afterwards the principal route by which the early expeditions across the continent at this point connected the Andean Plateau with the Amazon.
Many of the rivers of eastern Ecuador are subject to similar floods from the Andean slopes, which have cut away broad, deep channels, through the adjacent plains, leaving long, narrow ridges between their courses which the natives call cuchillas.
Among the many thermal springs throughout the Andean districts, the best known are at Belermos and San Pedro del Tingo, north-east of Quito; at Cachillacta, in the district of Nanegal; at Timbugpoyo, near Latacunga; at Banos (5906 ft.
The Caras, according to tradition, entered the country from the coast, and had thoroughly established themselves there long before the conquest by the Inca rulers Tupac-Yupanqui and his son Huayna-Capac. This conquest was comparatively easy because the Caras spoke a dialect of the same language, and were not greatly unlike their conquerors in manners and customs. The present Indian population of Ecuador, excepting those of the trans-Andean region, may be considered as descendants of these two races.
The northern part is fertile, as are the valleys of the Andean foothills, but arid conditions prevail throughout the central districts, and irrigation is necessary for the production of crops.
The vine is cultivated to some extent, and good pasturage is found on the Andean slopes.
The California vulture, the largest flying bird in North America and fully as large as the Andean condor, is not limited to California but is fairly common there.
The Frias is wholly a Chilean river, draining an extensive Andean region between the 44th and 45th parallels and discharging into the Puyuguapi channel, which separates Magdalena island from the mainland.
Lake Todos los Santos is situated well within the Andean foothills north-east of Puerto Montt and at an elevation of 509 ft., considerably above that of the other lakes, Lake Ranco being 230 ft.
The great Andean lakes of General Paz (near the 44th parallel), Buenos Aires (in lat.
Towards the north the coastal zone disappears beneath the sea and the Andean zone reaches to the shore.
The high altitudes of the Andean region also introduce vertical zones of temperature, modified to some extent by the rainless plateaus of the north, and by the excessive rainfall of the south.
There are also some remnants of tribes in the province of Chiloe, which inhabit the island of that name, the Chonos and Guaytecas archipelagoes and the adjacent mainland, who have the reputation of being good boatmen and fishermen; and there are remnants of a people called Changos, on the desert coast, and traces of Calchaqui blood in the neighbouring Andean foothills.
The completion of the Trans-Andean railway between Valparaiso and Buenos Aires was bound to be of immense commercial and industrial value; and eventually the making of a longitudinal railway route uniting the nitrate province of the north with Santiago, and Santiago with Puerto Montt in the distant south, opened up further important prospects.
Roughly calculated, two-fifths of the total area of Bolivia is comprised within the Andean cordilleras which cross its south-west corner and project east toward the Brazilian highlands in the form of a great obtuse angle.
The cordilleras, divided into two great parallel chains, with flanking ranges and spurs to the east, reach their greatest breadth at this point and form the massif of the Andean system.
West of the Cordillera Oriental, where special conditions prevail, a great desert plateau stretches entirely across one corner of the republic. Apart from the Andean system there is a group of low, broken, gneiss ranges stretching along the east side of Bolivia among the upper affluents of the Mamore and Guapore, which appear to belong to the older Brazilian orographic system, from which they have been separated by the erosive action of water.
A rare species of bear, the Ursus ornatus (spectacled bear) is found among the wooded Andean foothills.
Tobacco of a fair quality is produced in the warm regions of the east, including the yungas valleys of La Paz and Cochabamba; cacao of a superior grade is grown in the department of Beni, where large orchards were planted at the missions, and also in the warm Andean valleys of La Paz and Cochabamba; and coffee of the best flavour is grown in some of the warmer districts of the eastern Andes.
Cashmere, baize, waterproof ponchos of fine wool and silk, and many other fabrics are made by the Indians of the Andean departments.
On the Andean slopes the temperature is more agreeable.