is less heavily wooded, its surface more varied, and its Brazilian part stands at a much higher elevation.
Of the two highland regions of Brazil, that of the northern slope of the Amazon basin belongs physically to the isolated mountain system extending eastward from the Negro and Orinoco to the Atlantic, the water-parting of which forms the boundary line between the Guianas and Brazil. The culminating point is near the western extremity of this chain and its altitude is estimated at 8500 ft. The ranges gradually diminish in elevation towards the east, the highest point of the Tumuc-Humac range, on the frontier of French Guiana, being about 2600 ft. The Brazilian plateau slopes southward and eastward, traversed by broken ranges of low mountains and deeply eroded by river courses. The table-topped hills of Almeyrin (or Almeirim) and Ereré, which lie near the lower Amazon and rise to heights of 800 and 900 ft., are generally considered the southernmost margin of this plateau, though Agassiz and others describe them as remains of a great sandstone sheet which once covered the entire Amazon valley. Its general elevation has been estimated to be about 2000 ft. It is a stony, semi-arid region, thinly wooded, having good grazing campos in its extreme western section. Its semi-arid character is due to the mountain ranges on its northern frontier, which extract the moisture from the north-east trades and leave the Brazilian plateau behind them with a very limited rainfall, except near the Atlantic coast. The more arid districts offer no inducement for settlement and are inhabited only by a few roving bands of Indians, but there were settlements of whites in the grazing districts of the Rio Branco at an early date, and a few hundreds of adventurers have occupied the mining districts of the east. In general, Brazilian Guiana, as this plateau region is sometimes called, is one of the least attractive parts of the republic.
The great Brazilian plateau, which is the most important physical division of Brazil, consists of an elevated tableland 1000 to 3000 ft. above the sea-level, traversed by two great mountain systems, and deeply eroded and indented by numerous rivers. A thick sandstone sheet once covered the greater part if not all of it, remains of which are found on the elevated chapadas of the interior and on isolated elevations extending across the republic toward its western frontier. These chapadas and elevations, which are usually described as mountain ranges, are capped by horizontal strata of sandstone and show the original surface, which has been worn away by the rivers, leaving here and there broad flat-topped ridges between river basins and narrower ranges of hills between river courses. From the valleys their rugged, deeply indented escarpments, stretching away to the horizon, have the appearance of a continuous chain of mountains. The only true mountain systems, however, so far as known, are the two parallel ranges which follow the contour of the coast, and the central, or Goyana, system. The first consists of an almost continuous range crossing the northern end of Rio Grande do Sul and following the coast northward to the vicinity of Cape Frio, and thence northward in broken ranges to the vicinity of Cape St Roque, and a second parallel range running from eastern São Paulo north-east and north to the eastern margin of the São Francisco basin in northern Bahia, where that river turns eastward to the Atlantic. The first of these is generally known as the Serra do Mar, or Coast Range, though it is locally known under many names. Its culminating point is in the Organ Mountains (Serra dos Orgãos), near Rio de Janeiro, which reaches an elevation of 7323 ft. The inland range, which is separated from the Coast Range in the vicinity of Rio de Janeiro by the valley of the Parahyba do Sul river, is known as the Serra da Mantiqueira, and from the point where it turns northward to form the eastern rim of the São Francisco basin, as the Serra do Espinhaço. This range is also known under various local names. Its culminating point is toward the western extremity of the Mantiqueira range where the Itatiaya, or Itatiaia-assu, peak rises to an elevation of 8898 ft. (other measurements give 9823 ft.), probably the highest summit in Brazil. This range forms the true backbone of the maritime mountainous belt and rises from the plateau itself, while the Coast Range rises on its eastern margin and forms a rim to the plateau. North of Cape Frio the Coast Range is much broken and less elevated, while the Serra do Espinhaço takes a more inland course and is separated from the coast by great gently-sloping, semi-barren terraces. The second system—the Central or Goyana—consists of two distinct chains of mountains converging toward the north in the elevated chapadão between the Tocantins and São Francisco basins. The eastern range of this central system, which crosses western Minas Geraes from the so-called Serra das Vertentes to the valley of the Paracatú, a western tributary of the São Francisco, is called the Serra da Canastra and Serra da Matta da Corde. Its culminating point is toward its southern extremity in the Serra da Canastra, 4206 ft. above sea-level. The western range, or what is definitely known of it, runs across southern Goyaz, south-west to north-east, and forms the water-parting between the Paraná and Tocantins-Araguaya basins. Its culminating point is in the Montes Pyreneos, near the city of Goyaz, and is about 4500 ft. above sea-level.
The great part of this immense region consists of chapadões, as the larger table-land areas are called, chapadas or smaller sections of the same, and broadly excavated river valleys. How extensive this work of erosion has been may be seen in the Tocantins-Araguaya basin, where a great pear-shaped depression, approximately 100 to 500 m. wide, 700 m. long, and from 1000 to 1500 ft. deep, has been excavated northward from the centre of the plateau. Southward the Paraná has excavated another great basin and eastward the São Francisco another. Add to these the eroded river basins of the Xingú, Tapajós and Guaporé on the north and west, the Paraguay on the south-west, and the scores of smaller rivers along the Atlantic coast, and we may have some conception of the agencies that have been at work in breaking down and shaping this great table-land, perhaps the oldest part of the continent. The most southern of these chapadões, that of the Paraná basin, in which may be included the northern part of the Uruguay and eastern part of the Paraguay basins, includes the greater part of the states of Rio Grande do Sul, Santa Catharina, Paraná and São Paulo, the south-western corner of Minas Geraes, a part of southern Goyaz, and the south-eastern corner of Matto Grosso. The greatest elevation is on its eastern or Atlantic margin where the average is about 3280 ft. above sea-level. The plateau breaks down abruptly toward the sea, and slopes gradually some hundreds of feet toward the south and west. There has been considerable denudation toward the west, the eastern tributaries of the Paraná rising very near the coast. The northern and western parts of this plateau have an average elevation a little less than that of the Atlantic margin, and their slopes are toward the south and east, those of Goyaz and Matto Grosso being abrupt and deeply eroded. This great chapadão is in many respects the best part of Brazil, having a temperate climate, extensive areas of fertile soil, rich forests and a regular rainfall. Its Atlantic slopes are heavily wooded, but the western slopes exhibit grass-covered campos between the river courses. The São Francisco chapadão, which has a general elevation of about 2600 ft., covers the greater part of the states of Minas Geraes and Bahia, and a small part of western Pernambuco, and might also be considered continuous with those of the Parnahyba and Tocantins-Araguaya basins. This region is more tropical in character, partially barren, and has an uncertain rainfall, a large part of the São Francisco basin and the upper Atlantic slope of its eastern rim being subject to long-continued droughts. This region is well wooded along the river courses of Minas Geraes, the lower Atlantic slopes of Bahia, which are perhaps outside the plateau proper, and on the weather side of some of the elevated ridges where the rainfall is heavy and regular. It has extensive campos and large areas of exposed rock and stony steppes, but is richly provided with mineral deposits. It breaks down less abruptly toward the Atlantic, the slopes in Bahia being long and gradual. The Parnahyba chapadão covers the state of Piauhy, the southern part of Maranhão, and the western part of Ceará. Its general elevation is less than that of the São Francisco region, owing to the slope of the plateau surface toward the Amazon depression and to denudation. It resembles the São Francisco region in its uncertain rainfall and exposure to droughts, and in having large areas of campos suitable for grazing purposes. It is thinly wooded, except in the north, where the climatic conditions approach those of the Amazon valley. Its climate is more tropical and its development has gone forward less rapidly than in the more temperate regions of the south. The Amazonian chapadão, which includes the remainder of the great Brazilian plateau west of the São Francisco and Parnahyba regions and which appears to be the continuation of these tablelands westward, is much the largest of these plateau divisions. It covers the greater part of the states of Matto Grosso and Goyaz, a large part of southern Pará, the southern margin of Amazonas, and a considerable part of western Maranhão. It includes the river basins of the Tocantins-Araguaya, Xingú, Tapajós, and the eastern tributaries of the Guaporé-Madeira. A considerable part of it has been excavated by these rivers to a level which gives their valleys the elevation and character of lowlands, though isolated hills and ranges with the characteristic overlying horizontal sandstone strata of the ancient plateau show that it was once a highland region. The southern margin of this plateau breaks down abruptly toward the south and overlooks the Paraná and Paraguay basins from elevations of 2600 to 3000 ft. There is great diversity in the character and appearance of this extensive region. It lies wholly within the tropics, though its more elevated districts enjoy a temperate climate. Its chapadas are covered with extensive campos, its shallow valleys with open woodlands, and its deeper valleys with heavy forests. The rainfall is good, but not heavy. The general slope is toward the Amazon, and its rivers debouch upon the Amazonian plain through a succession of falls and rapids.
There remains only the elevated valley of the Parahyba do Sul, lying between the so-called Serra das Vertentes of southern Minas Geraes and the Serra do Mar, and extending from the Serra da Bocaina, near the city of São Paulo, eastward to Cape Frio and the coastal plain north of that point. It includes a small part of eastern São Paulo, the greater part of the state of Rio de Janeiro, a small corner of Espirito Santo, and a narrow strip along the southern border of Minas Geraes. It is traversed by two mountain chains, the Serra da Mantiqueira and Serra do Mar, and the broad, fertile valley of the Parahyba do Sul which lies between them, and which slopes gently toward the east from a general elevation exceeding 2000 ft. in São Paulo. This region is the smallest of the chapadão divisions of the great plateau, and might be considered either a southward extension of the São Francisco or an eastward extension of the Paraná chapadão. It is one of the most favoured regions of
