Amazon river dolphin widespread river dolphins. They are present in six countries in South America: Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela, in an area covering about . The boundaries are set by waterfalls, such as the Xingu and Tapajós rivers in Brazil, as well as very shallow water. A series of rapids and waterfalls in the Madeira River have isolated one population, recognized as the subspecies "I. g. boliviensis", in the southern part of the Amazon basin in Bolivia. They are also distributed in the basin of the Orinoco River, except the Caroni River and the upper Caura River in Venezuela. The
Red River of the South and Spain. That boundary continued to be recognized when Mexico gained its independence from Spain, then again when Texas became independent from Mexico. It remained so until the United States Congress consented to the Red River Boundary Compact adopted by the states of Oklahoma and Texas, which set the jurisdictional boundary between Texas and Oklahoma at the vegetation line on the south bank, but left title of adjacent property owners at the south bank. The Red River Campaign (March–May 1864) was fought along the Red River Valley in Louisiana during the American Civil War. It was a failed attempt by