Description: ÒProduction of phosphate, nitrates, and potash in Africa in 1913É Each dot represents 1 per cent of worldÕs production. A cross represents less than 1/2 per cent of worldÕs productionÉMandatories for former German colonies and changes in boundaries of territories in Africa are shown on map of Africa in the introductory text. May 1, 1920. — Department of the Interior, 1921
Source: Department of the Interior , World Atlas of Commercial Geology (Washington, DC: Department of the Interior , 1921) Plate 52
Map Credit: Courtesy the private collection of Roy Winkelman |
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