Eau Claire Formation Stratigraphic range: Cambrian |
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Type | Formation |
Underlies | Galesville Sandstone or Potosi Dolomite |
Overlies | Mount Simon Sandstone |
Thickness | 400 to 1000 feet in Indiana |
Lithology | |
Primary | Sandstone |
Other | Siltstone, shale, dolomite |
Location | |
Region | Indiana, Illinois, Wisconsin, Michigan, western Ohio, and western Kentucky. Equivalent to the Bonneterre Formation in Missouri |
Country | United States |
Type section | |
Named for | Outcrops along the Eau Claire River, Eau Claire County, Wisconsin |
Named by | E. O. Ulrich |
The Eau Claire Formation is a geologic formation in the north central United States. It preserves trilobite fossils from the Cambrian Period.