Source: Michigan Basinarchive copy at the Wayback Machine, The North American Tapestry of Time and Terrain, United States Department of the Interior. Text from this web page follows below.
A giant incomplete bull's-eye is centered on the state of Michigan. Radiating outward to Ohio, Indiana, Illinois, Wisconsin, and Ontario, this annular pattern outlines the Michigan Basin. The Basin is a bowl-shaped structure of uncertain origin that contains over 2.5 miles (4 km) of inward-dipping Paleozoic strata and a veneer of Jurassic sedimentary rocks. This curious basin is located in the less tectonically-active interior of the continent, bordered by the Appalachian and Rocky Mountains. It subsided rapidly from Cambrian to Silurian time and filled with shallow-water marine sediments, some of which contain deposits of petroleum, coal, and salt.
A geological map of the Michigan Basin. Source: [http://nationalatlas.gov/articles/geology/features/michiganbasin.html Michigan Basin], The North American Tapestry of Time and Terrain, United States Department of the Interior. Text from this web page fo
File usage
The following pages on the English Wikipedia use this file (pages on other projects are not listed):