1. Distribution and abundance of copper, lead, and zinc in nonmagnetic and moderately magnetic heavy-mineral-concentrate and minus-80-mesh stream sedimemnt samples and ash of aquatic-bryophyte samples, Medfra quadrangle, Alaska [cartographic material] Yale Public content 1984. 2002-06-01T04:00:00Z. 2022-12-17T04:01:22Z. Geological Survey (U.S.). The Survey. English. cartographic image. Public. Alaska.