. The earth and its inhabitants ... Geography. CHAPTER VIL THE TOC.^'TINS BASIN-STATE OF IHE Tocantins hydrogrciphic system is closely connected with that of the Amazons. If, as seems probable, a continuous subsidence of the old marine bed has given access to the Atlantic waters, causing them to flood the lands at present occupied by the Amazonian gulf, the Tocantins must at one time have communi- cated directly with the Amazons through a confluence lying to the east of Marajo Island. It was thus a simple affluent of the great river. In any case it flows from the same slope as the Xing
. The earth and its inhabitants ... Geography. CHAPTER VIL THE TOC.^'TINS BASIN-STATE OF IHE Tocantins hydrogrciphic system is closely connected with that of the Amazons. If, as seems probable, a continuous subsidence of the old marine bed has given access to the Atlantic waters, causing them to flood the lands at present occupied by the Amazonian gulf, the Tocantins must at one time have communi- cated directly with the Amazons through a confluence lying to the east of Marajo Island. It was thus a simple affluent of the great river. In any case it flows from the same slope as the Xingu, the l^apajoz, and the other southern tributaries of the main stream, and its course is developed in the same direction. But the Tocantins, rising in the very heart of the Brazilian orographic system, is conterminous about the region of its sources with two other large fluvial basins, those of the S. Francisco and the Parana. Hence it has been proposed to found a new capital of the federal republic on this dividing line near the diverging point of three great rivers. There is no coincidence between the political frontiers of Goyaz and the natural limits of the Tocantins catchment basin. Goyaz, the superficial area of which may be approximately estimated at about 800,000 square miles, occupies south of the Pyreneos divide part of the southern slope draining to the Parana, and towards the west it comprises no more than one-half of the Araguaya Valley ; the channel of this river in fact forms its frontier towards Matte Grosso and Amazonia. The drainage area itself is otherwise very sharply defined. An oval- shaped cirque is developed round the sources of the two main branches— Tocantins and Araguaya—and this cirque is closed northwards by the rocky ridges where are formed the last fluvial cataracts. The outer walls of this vast amphitheatre are formed, if not by distinct mountain ranges, at least by the escarpments of a plateau. Towards the east especially the edge of the ba
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