| |
| | Geology (Site not responding. Last check: ) |
 | | These rock formations, consisting largely of shales, limestones, and sandstones, were deposited on the bottom of ancient seas that covered Michigan on and off for millions of years. |
 | | The igneous rocks are hard, crystalline, resistant to erosion, and are largely made up of granites and metamorphic rocks--rocks that have been changed through heat and pressure--composed mainly of gneisses and schists. |
 | | As you now know, the geology of Michigan is dominated by two rock formations: the sedimentary Michigan Basin, which covers the entire Lower Peninsula and the eastern half of the Upper Peninsula, and the old crystalline, igneous shield found in the western Upper Peninsula. |
| www.geo.msu.edu /geo333/geology.html (644 words) |
|