GRAN CHACO, an extensive region in the heart of South America belonging to the La Plata basin, stretching from 2o° to 29° S. lat. Its area is estimated at 300,00o sq. miles. The greater part is covered with marshes, lagoons and dense tropical jungle and forest, and is still unexplored. On its southern and western borders there are extensive tracts of open woodland, intermingled with grassy plains, while on the northern side in Bolivia are large areas of open country subject to inundations in the rainy season. It is traversed by two great rivers, the Pilcomayo and Bermejo, whose sluggish courses are not navigable. The greater part of its territory is occupied by nomadic tribes of Indians, some of whom are still unsubdued, while others like the Matacos, are sometimes to be found on neighbouring sugar estates and estancias as labour ers during the busy season. The forest wealth of the Chaco region is incalculable, consisting of a great variety of palms and valuable cabinet woods, building timber, etc. Its extensive tracts of que bracho colorado (Loxopterygium Lorentzii) are of very great value because of its use in tanning leather. Both the wood and its extract are largely exported. Its possession was the cause of serious dispute and armed conflict between Bolivia and Paraguay commencing in the winter of 1928. (See CHACO.)