Geography of Michigan - Geology

Geology

The geological formation of the state is greatly varied. Primary boulders are found over the entire surface of the Upper Peninsula (being principally of primitive origin), while Secondary deposits cover the entire Lower Peninsula. The Upper Peninsula exhibits Lower Silurian sandstones, limestones, copper and iron bearing rocks, corresponding to the Huronian system of Canada. The central portion of the Lower Peninsula contains coal measures and rocks of the Permo-Carboniferous period. Devonian and sub-Carboniferous deposits are scattered over the entire state.

The soil is of a varied composition and in large areas is very fertile, especially in the south. However, the Upper Peninsula for the most part is rocky and mountainous, and the soil is unsuitable for agriculture. The climate is tempered by the proximity of the lakes and is much milder than in other locales with the same latitude. The principal forest trees include basswood, maple, elm, sassafras, butternut, walnut, poplar, hickory, oak, willow, pine, birch, beech, hemlock, witchhazel, tamarack, cedar, locust, dogwood, and ash.