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 Brazil, having an abundant rainfall, extensive forests of valuable timber, and large areas of fertile soil. The mountain slopes are still masses of dense forest, though their lower elevations and neighbouring valleys have been cleared for cultivation and by dealers in rosewood and other valuable woods. This elevated valley is noted for its fertility and was once the principal coffee-producing district of Brazil.
Outside the two great river systems of the Amazon and river Plate (Rio de la Plata), which are treated under their respective titles, the rivers of Brazil are limited to the numerous small streams and three or four large rivers which flow eastward from the plateau regions directly into the Atlantic. The Amazon system covers the entire north-western part of the republic, the state of Amazonas, nearly the whole of Pará and the greater part of Matto Grosso being drained by this great river and its tributaries. If the Tocantins-Araguaya basin is included in the hydrographic system, the greater part of Goyaz and a small part of Maranhão should be added to this drainage area. The Tocantins is sometimes treated as a tributary of the Amazon because its outlet, called the Rio Pará, is connected with that great river by a number of inland channels. It is an entirely separate river, however, and the inland communication between them is due to the slight elevation of the intervening country above their ordinary levels and to the enormous volume of water brought down by the Amazon, especially in the flood season. As the outlet of the Tocantins is so near to that of the Amazon, and their lower valleys are conterminous, it is convenient to treat them as parts of the same hydrographic basin.