1. Bedrock geologic map of the Kenton-Perch Lake area, northern Michigan [cartographic material] Yale Public content 1980. 2015-06-29T13:57:17Z. 2015-07-14T22:10:06Z. Cannon, William F. U.S. Geological Survey. English. cartographic image. Public. Michigan, Baraga County, Gogebic County, Houghton County, Iron County, Ontonagon County, and U.S.