Geology of Minnesota

Lake Harriet Region

The continental glaciers spreading over Minnesota during the great ice ages brought vast quantities of rock material from the north to be dumped indiscriminately during the recession of the ice. Old river valleys were filled and belts of ...

Geology of Minnesota

Red Wing Region

During the great ice ages the landscape of Minnesota was profoundly altered by continental glaciers in four major epochs of glaciation. In this area, as elsewhere, the closing stage of each epoch was characterized by the release ...

Geology of Minnesota

Jay Cooke State Park

This point overlooks the St. Louis River Valley. The steeply inclined rocks in the river channel upstream are alternating beds of slates and graywackers of the Thompson Formation thousands of feet thick.

Slates are rocks formed from original ...

Geology of Minnesota

Stillwater Region

The site of this tablet marks the northern limit of Lake St. Croix, impounded by the natural dam of sand and gravel, made by the Mississippi where it is joined by the St. Croix River, twenty miles below Stillwater. ...