America, South: Figure 3. Part of the entrance to Casa de Pedra cave, Ribeira karst, Brazil. The entrance is thought to be the highest in the world at 215 m. The stream-sink at the bottom left leads to a fine river passage. (Photo by John Gunn)

Brazilian quartzite caves occur mostly in the eastern portion of the country (see Quartzite Caves of South America), and comprise the deepest and longest caves known in this type of rock. Sandstone karst is widespread throughout Brazil, from the

southern provinces to Amazonia. The best-developed areas lie in rocks of the Furnas and Botucatu formations, including the 1400 m long Caverna Aroe Jari at Chapada dos Guimarães, Mato Grosso State. In Amazonia, the Prainha area has some long sandstone caves, such as the 1297 km long Gruta Planaltina. The longest sandstone cave in Brazil is currently the 1633 m long Toca das Confusões in the semi-arid region of the state of Piauí. Another cave of note is the 1600 m long Caverna dos Ecos, developed in mica schists (Karmann, Sánchez & Fairchild, 2001). Caves in granite, talus, bauxite, and under laterite have also been recorded.