The Cordillera Real, northern section of the east Andean range of Bolivia, contains relatively abundant tin and tungsten deposits, genetically related to a number of granitic intrusions which cut a thick series of Paleozoic shales and sandstones. "Several examples of wall- rock control are described. Analysis of the vein pattern suggests that fracturing was the result of regional shearing forces rather than local stresses. Mineralogically the high-temperature ores, tin and tungsten, predominate, but some lead-zinc and antimony ores are indicative of a cooler environment. . . . The deposits are believed to have been formed at intermediate depth with intensities ranging from hypothermal to leptothermal."