Dubuque Formation

Not to be confused with DeBeque Formation.

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]

Dubuque Formation
Stratigraphic range: Ordovician
Type	Formation
Underlies	Maquoketa Formation
Overlies	Galena Group
Location
Region	Illinois, Minnesota
Country	United States

See also

• List of fossiliferous stratigraphic units in Illinois
• List of fossiliferous stratigraphic units in Iowa
• List of fossiliferous stratigraphic units in Minnesota
• List of fossiliferous stratigraphic units in Wisconsin