Dubuque Formation | |
---|---|
Stratigraphic range: Ordovician | |
Type | Formation |
Underlies | Maquoketa Formation |
Overlies | Galena Group |
Location | |
Region | Illinois, Minnesota |
Country | United States |
The Dubuque Formation is a geologic formation in Illinois, Iowa, Wisconsin and Minnesota. It preserves fossils dating back to the Ordovician period. [1] It comprises carbonate and argillaceous rocks that are between 35 and 45 feet deep. [2]
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