Duffield, Susan L.Base map by U.S. Geological Survey.Scale approximately 1:500,000compiled by Susan L. Duffield ; cartographer, R. Anne Berry.TIFFhttps://hdl.handle.net/1811/f70d2ce3-4fff-4217-a7f6-9362b38eab9bengOhio. Division of Geological SurveyPublicMineral industriesMineral industries map of Ohio, 1977MapsOhioThe Ohio State University