The principal bauxite deposits of Jamaica are located in the parishes of Manchester, St. Elizabeth and St. Ann. They are surface accumulations, and show a close relationship to the fault pattern of the region. The distance between the top of the White Limestone and the impervious formations below determine the degree of desilication of the deposits. Gibbsite, boehmite, iron oxide, kaolinite and quartz are the most abundant minerals. Field and laboratory evidence indicate that the White Limestone is the source of the ore, and by comparison with other deposits and phase equilibria work on related systems it is deduced that a volcanic ash could not be the source material. This approach further suggests that the deposits are not in equilibrium, because the mineralogy is not consistent.