Description: ÒProduction and consumption of copper, lead, and zinc in North America in 1913É Each dot represents 1 per cent of worldÕs production. A cross represents less than 1/2 per cent of worldÕs production. In Mexico all lead producing districts are indicated by crosses. — Department of the Interior, 1921
Source: Department of the Interior , World Atlas of Commercial Geology (Washington, DC: Department of the Interior , 1921) Plate 34
Map Credit: Courtesy the private collection of Roy Winkelman |
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