Type Formation Primary Sandstone Underlies Potosi Formation | Country United States Overlies Mount Simon Sandstone | |
Thickness 400 to 1000 feet in Indiana Other Siltstone, shale, dolomite Region Indiana, Illinois, Wisconsin, Michigan, western Ohio, and western Kentucky. Equivalent to the Bonneterre Formation in Missouri Named for Outcrops along the Eau Claire River, Eau Claire County, Wisconsin | ||
The Eau Claire Formation is a geologic formation in the north central United States. It preserves trilobite fossils from the Cambrian Period.
References
Eau Claire Formation Wikipedia(Text) CC BY-SA