There are two main divisions of this mountain group, the Portuguesa chain south of Barquisimeto, and the Cordillera of Mérida constituting the more important and higher part. The Portuguesa chain reaches its greatest elevation (13,100 feet) in the south near the sources of the Tocuyo, the northern portion rising only to about 5,000 feet. A slight break in the mass is caused by the valley of the Boconó, beyond which the Cordillera of Mérida begins with peaks of nearly 13,000 feet on the north, rising to their maximum in the centre, where the summits of the Sierra Nevada of Mérida have an elevation of about 16,400 feet, and the top of the highest of all, La Columna, is 16,423 feet above sea-level. Southwards the elevations decrease again, until on the borders of Colombia the watershed is less than 5,000 feet above the sea. The streams of this chain, with its steep outer flanks so characteristic of the Andes, naturally belong for the most part to the catchment area of the Orinoco or the Maracaibo Lake, but there is a succession of longitudinal valleys within the chain which may be considered as pertaining more particularly to the Andes. The chief of these rivers are the Motatán, which, rising north of Mérida, flows northwards through Trujillo to the Lake of Maracaibo; the Chama, whose sources are in the same snows that supply the Motatán, though the stream flows southward past Mérida, bending then sharply northward to reach the south shore of the lake opposite the mouth of the Motatán; and the Torbes, flowing south-westward by San Cristobal, and turning there to the east to fall into the Uribante, a tributary of the Apure. Every type of vegetation occurs within this Andine tract, varying according to the geology of the ground and its elevation. At some points there are fertile valleys with tropical flora, others with temperate cereals; sometimes bare mountain slopes and hot gorges supporting only cactus and acacia, and little of these; sometimes grass-clad slopes and summits, with the peculiar heather-like and resinous plants of the “páramos,” and, lastly, the eternal snows of the peaks of the Sierra Nevada.