Gran Chaco

Gran Chaco, an extensive central tract of South America, extending from the southern tropic to 29° S. lat., and bounded on the E. by the Paraguay and Paraná, and on the W. by the Argentine provinces of Santiago del Estero and Salta. Its area, about 180,000 sq. m., exceeds that of Great Britain and Ireland by one-half. The portion south of the Pilcomayo belongs to Argentina, and the remaining third to Paraguay; but the possession of the upper section of the Pilcomayo is disputed by Bolivia. The country rises gradually from the Paraná towards the north-west as far as 25° 40' S. lat., when it dips to the valley of the San Francisco—part of a great depression extending through Bolivia nearly to the frontier of Peru, and subject to annual inundations. The Chaco is watered principally by two long, narrow, and tortuous streams, the Bermejo and the Pilcomayo, flowing south-east in courses generally parallel, and about 180 miles distant from each other. Only the former has been explored throughout, but it is known that both possess an unusual number of obstructions, though these are quite removable, consisting mainly of shallows caused by the compact argilaceous bed which is a geological characteristic of the whole Chaco subsoil. The bed of the Bermejo also oscillates backward and forward, and in 1870-72 the river opened up a new channel (known as the Teuco) for nearly 200 miles. The most northern part of the Chaco is an extremely arid zone, but the banks of the upper Pilcomayo are fertile and its sands auriferous. To the north of the Bermejo there are numerous and wide marshes and stretches of jungle, drained by many small streams; but the land is well wooded, chiefly with vast seas of palms (here an indication, however, of marshy lands subject to inundation, as the local algaroba is of dry, high land), while south of the Bermejo the primeval forest extends into Salta. The annual rainfall is probably 80 inches, all concentrated into the six months from November to May; then wide sections become almost a lake district, whilst in seasons of extraordinary floods the Paraguay and the other great rivers create a vaster sea than the Nile. Thus much of the region is of modern alluvial formation, and exceedingly fertile. A very dry season succeeds, and some districts are then utterly waterless, or the wells that have been sunk are impregnated with salt. The average temperature is 80° F.; the climate is said to be equable, and in the southern section suitable to colonists of the Anglo-Saxon race. Since 1537, when the first explorer, Captain Juan de Ayolas, marched with 250 men into the wilderness from which none ever returned, numerous expeditions have been sent out from the surrounding countries; but the savage tribes (still unsubdued throughout the unexplored interior), swamps, lagoons, and floods defeated all early attempts to open up the country. In 1884 garrisons were established along the Bermejo, and since 1885 permanent settlements have been made. Already there are many agricultural colonies and small towns along the Paraguay, connected by rail and telegraph; the Bermejo lands, on both banks for 400 miles from its mouth, have been conceded by the Argentine government for various enterprises; thousands of hands are employed in the timber trade, and steam sawmills are in operation; cattle-raising and farming are carried on, and from the sugar-cane refined sugar and rum are manufactured. Concessions also have been granted for railways from Corrientes to the Bolivian frontier. See an interesting paper by Captain John Page in Proc. Roy. Geog. Soc. (1889).—Chacu, the Quichua word for 'hunt,' may refer to the great Indian battues; but under the Incas it was applied to the numbering of flocks, and so came to signify wealth—Gran Chaco thus meaning 'great riches.'