1. Bedrock geologic map of the Ashland and the northern part of the Ironwood 30ʹ x 60ʹ quadrangles, Wisconsin and Michigan Yale Public content 1996. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Information Services. English. Public. Michigan, Gogebic County, and Wisconsin.