The Steppe extends from the littoral chain of Caracas to the forests of Guiana, and from the snow-covered mountains of Merida, on whose declivity lies the Natron lake of Urao,—the object of the religious superstition of the natives,—to the vast delta formed by the mouth of the Orinoco. To the south-west it stretches like an arm of the sea[13], beyond the banks of the Meta and of the Vichada, to the unexplored sources of the Guaviare, and to the solitary mountain group to which the vivid imagination of the Spanish warriors gave the name of _Paramo de la Suma Paz_, as though it were the beautiful seat of eternal repose. This Steppe incloses an area of 256,000 square miles. Owing to inaccurate geographical data, it has often been described as extending in equal breadth to the Straits of Magellan, unmindful that it is intersected by the wooded plain of the Amazon, which is bounded to the north by the grassy Steppes of the Apure, and to the south by those of the Rio de la Plata. The Andes of Cochabamba and the Brazilian mountains approximate each other by means of separate transverse spurs, projecting between the province of Chiquitos and the isthmus of Villabella[14]. A narrow plain unites the _Hylæa_ of the Amazon with the Pampas of Buenos Ayres. The area of the latter is three times larger than that of the Llanos of Venezuela; indeed so vast in extent, that it is bounded on the north by palms, while its southern extremity is almost covered with perpetual ice. The Tuyu, which resembles the Cassowary, (Struthio Rhea,) is peculiar to these Pampas, as are also those herds of wild dogs[15], which dwell in social community in subterranean caverns, and often ferociously attack man, for whose defence their progenitors fought. Like the greater part of the desert of Sahara[16], the Llanos, the most northern plains of South America, lie within the torrid zone. Twice in every year they change their whole aspect, during one half of it appearing waste and barren like the Lybian desert; during the other, covered with verdure, like many of the elevated Steppes of Central Asia[17]. The attempt to compare the natural characteristics of remote regions, and to pourtray the results of this comparison in brief outline, though a gratifying, is a somewhat difficult branch of physical geography.