The natural history of the Gran Chaco has been well described by Felix de Azara. The fauna, though abundant, are not particularly remarkable, and differ in few particulars from those of other South American forest tracts. Vegetation grows in boundless profusion, and the most valuable product is timber, of which a brief description is given in one of the industrial chapters. An Argentine writer[152] remarks: "The forest land or woody portion of the Chaco can be said to occupy a third part of the total area of the territory. The woods of the Chaco are met with on the banks of rivers to which they make a broad fringe; also in clumps or masses of trees more or less extensive; or as brows of brush, as they are called in the neighbourhood--that is to say, narrow strips of trees stretching from one clump to the other--or else scattered in the form that is called thin bush. These varied formations are not capricious. They obey geological laws with that regularity which Nature demands from her handiwork, seeing that the Chaco has no artificially planted trees whatever." The Gobernacion of the Chaco itself is a comparatively small region, not very much larger than England and Wales, and the population is only 13,937. It is bounded on the north by the Vermejo, on the east by the Parana and Paraguay, and on the west by the Provinces of Santiago del Estero and Salta. The north is marshy, the south is covered with dense forests. The capital is Resistencia, but the only place in the Territory which has any railway communication with the outer world is La Sabana, which is on a narrow-gauge railway to Santa Fé. A line, however, is projected to run through Chaco into Bolivia. In this work the term Gran Chaco is used, as it was by the old Spaniards, to embrace all the tropical and semi-tropical north, and this opportunity is taken of giving a brief account of a few of the more interesting places, most of which are, thanks to the railways, now within easy reach of Buenos Aires.