9781422286494

An Exotic Land 13

rise south and east of the Orinoco River. Erosion has created strange forma- tions here. The highlands are mainly plateaus cut into pieces by running trib- utaries of the Orinoco. The most eye-catching plateau is the Gran Sabana, a giant, deeply eroded formation that rises from surrounding areas as a collec- tion of steep cliffs. Above the rolling surface of the Gran Sabana, massive, flat-topped tepuíes emerge. The world’s highest waterfall, Angel Falls, tum- bles over one of these tepuíes . The Water System of Venezuela The Orinoco is by far the most important of the more than 1,000 rivers in Venezuela. It flows more than 1,554 miles (2,500 km) to the Atlantic from its source in the Guiana Highlands at the Brazilian border. The Orinoco is the world’s eighth-largest river and the second-largest in South America (after the Amazon). Its depth and the speed of its current change with the seasons. In August, for example, the Orinoco is 40 feet (12 meters) higher than it is in March and April. Downstream from its headwaters , the Orinoco splits into two. One-third of its flow passes through the Brazo Casiquiare (Casiquiare Channel) into a tributary of the Amazon, and the rest passes into the main Orinoco channel. Most of the rivers rising in the northern mountains flow southeastward to the Río Apure. From its headwaters, the Apure crosses the llanos in a generally eastward direction. Few rivers flow into it from the poorly drained region south of the river. Much of the region near the Colombian border is swampland. The other major Venezuelan river is the fast-flowing Caroní, which starts