CHAPTER XI.

OF THE RIVERS PARAGUAY, PARANA, AND URUGUAY.

Importance of the rivers of the United Provinces. The Paraguay and its tributaries. The Pilcomayo. The Vermejo. Soria's expedition down it from Oran, proving it navigable thence to Assumption. Periodical inundations of the Parana, similar to those of the Nile. The Uruguay and its affluents. Surveys by the Commissioners appointed to determine the Boundaries laid down by the Treaty between Spain and Portugal of 1777. Original Maps obtained.

BEFORE proceeding to give any account of the Upper Provinces, a brief description will perhaps here not be out of place of the great rivers which form so remarkable a feature in the physical geography of this part of the South American continent, and from the navigation of which by steamvessels hereafter such important political consequences may be anticipated.

Of these, the Paraguay is the first. This river, which from Corrientes takes the name of Parana, has its sources between south lat. 13° and 14°, in those ranges which, though of very trifling elevation themselves, appear to connect the lofty mountains of Peru and Brazil, and to constitute the water-shed of some of the principal rivers of South America. From their northern declivities descend some of the most important of the eastern affluents of the Madera, the Tapajos, and other great streams which empty

themselves into the Maranon, or Amazons; whilst, on the other hand, all those which pour down towards the south find their way into the bed of the wonderful river I am describing.

Many navigable streams join it from the eastward, as it passes through the rich Brazilian territories of Matto Grosso and Cuyabá. Its tributaries from the opposite side are, though perhaps more important, less numerous, the surface of the country being more level; of these the Jaurú is the first of any consequence, the sources of which are close to those of the Guaporé, which runs in the opposite direction into the Madera and Amazons. The short portage which intervenes between the heads of these rivers is all that breaks a continuous water-course from the mouths of the Amazons to that of the Plata, as will be seen on reference to the map. A little below the Jaurú commences a wide region of swamps called the lake or lakes of Xarayes; which, during the periodical inundations of the rivers that descend from the mountains to the north of Cuyabá, is flooded for a vast extent, the waters forming one great inland sea, to the depth of ten or twelve feet, extending between 200 and 300 miles east and west, and upwards of 100 from north to south. As the rainy season passes away, this mass of waters is finally carried off by the Paraguay, which even here, 1200 miles in a direct line from the sea, is navigable for vessels of 40 or 50 tons. The mouth of the Jaurú is in 16° 25′ long. 320° 10' east of Ferro-here a

AND ITS AFFLUENTS.

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marble pyramid is erected to mark the boundary determined upon between the Spaniards and Portuguese by the treaty of 1750.

Quiroga, who accompanied Flores, the Spanish commissioner, to determine this point, in descending the Paraguay fixed the latitude of most of the numerous rivers which fall into it before its junction with the Parana.* On the eastern side they afford the means of communication with the gold and diamond districts of Brazil, and lower down with those districts of Paraguay proper which abound in the finest timber, and produce the yerba maté, the article perhaps most in demand of all the rich productions of that favoured country.

From the west its most important affluents are the Pilcomayo and the Vermejo, which fall into it below Assumption:-both flow through a prodigious extent of country, having their sources in the rich districts of Upper Peru. The first passes not far from Potosi, and, after a thousand windings through the chaco, or desert, falls into the Paraguay by two branches, the one called the Araquay, in lat. 25° 21' 29", according to an observation taken by Azara; the other, about nine leagues below it. M. de Angelis has I think clearly shown that the river to the north of Assumption, which Azara has laid down as the most northern branch of the Pilcomayo, is the Fogones of Quiroga.

* His positions will be found in the tables of fixed points given in the Appendix.