Prevalent concentration of dissolved minerals in surface water / adapted from U. S. Geological Survey, Prevalent dissolved-solids concentration of rivers, HA-61, Washington, USGS, 1962, pl. 1, map 1:7,000,000, conterminous U. S. -- Concentration of dissolved minerals in ground water / adapted from U. S. Geological Survey, Depth to and quality of shallowest ground water containing more than 1,000 parts per million of dissolved, HA-199, Washington, USGS, 1965, sheet 1, map 1:3,168,000, conterminous U. S. Published in 1970. https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~341334~90109476

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