Extending down the middle of the continent is a series of lowlands running southward from the llanos of the north, through the selva of the great Amazon basin and the Gran Chaco, to the Pampa of Argentina. Paralleling the Pacific shore is the great cordillera composed of the Andes ranges and high intermontane valleys and plateaus. The Andes region is seismically active and prone to earthquakes.
Volcanoes are present but mostly inactive.
Patagonia, a windy, semiarid plateau region, lies to the E of the Andes in S Argentina. On the Pacific coast, the land between the Andes and the sea widens northward from the islands of S Chile. In N Chile lies the barren Atacama Desert. There are few good natural harbors along the South American coast. Only short streams flow into the Pacific Ocean.