ABSTRACT
Amazon drainage basin follows the summit of the highest range. In the southeast, the Amazon basin is mainly covered with savanna (cerrado) vegetation. The boundaries between the various pairs of countries in this part of South America do not follow the watersheds or the limits of the forest. They mostly cut through still very sparsely populated areas, and have frequently been disputed since the countries became independent early in the nineteenth century (Guyana and Suriname more recently).
