| 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.
The St. Peter Sandstone is an Ordovician geological formation. It belongs to the Chazyan stage of the Champlainian series in North American regional stratigraphy, equivalent to the late Darriwilian global stage. This sandstone originated as a sheet of sand in clear, shallow water near the shore of a Paleozoic sea and consists of fine-to-medium-size, well-rounded quartz grains with frosted surfaces. The extent of the formation spans north-south from Minnesota to Arkansas and east-west from Illinois into Nebraska and South Dakota. The formation was named by Owen (1847) after the Minnesota River, then known as the St. Peter River. The type locality is at the confluence of the Mississippi and Minnesota Rivers near Fort Snelling, Minnesota. In eastern Missouri, the stone consists of quartz sand that is 99.44% silica.
The Jordan Formation is a siliciclastic sedimentary rock unit identified in Illinois, Michigan, Wisconsin, Minnesota, and Iowa. Named for distinctive outcrops in the Minnesota River Valley near the town of Jordan, it extends throughout the Iowa Shelf and eastward over the Wisconsin Arch and Lincoln anticline into the Michigan Basin.
The Salem Formation is a geologic formation in Illinois, Indiana, Kentucky, and Missouri. It preserves fossils dating back to the Mississippian subperiod. This formation is quarried and used as a building material, known as "Indiana limestone", also called Bedford limestone.
The Cedar Valley Group is a geologic group in Iowa and Illinois. It preserves fossils dating back to the Devonian period.
The Chouteau Limestone is a geologic formation in Illinois, Iowa, Kansas, and Missouri. It preserves fossils dating back to the Carboniferous period.
The Keokuk Limestone is a geologic formation in Illinois, Iowa and Missouri. It preserves fossils dating back to the Mississippian sub-period.
The Warsaw Formation is a geologic formation in Illinois, Iowa and Missouri. It preserves fossils dating back to the Mississippian subperiod.
The Kimmswick Limestone is an Ordovician geologic formation in Arkansas, Illinois and Missouri. Fossils occurring in the Kimmswick include corals, bryozoans, brachiopods, conodonts, trilobites, crinoids and mollusks.
The Maquoketa Formation is a geologic formation in Illinois, Indiana. Iowa, Kansas, Minnesota, Missouri, and Wisconsin. It preserves mollusk, coral, brachiopod and graptolite fossils dating back to the Darriwilian to Hirnantian stages of the Ordovician period.
The Gower Formation is a geologic formation in Illinois and Iowa. It preserves fossils dating back to the Silurian period.
The Franconia Formation is a geologic formation in the upper mid-western United States, with outcroppings found in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, and Wisconsin. It preserves fossils dating back to the Cambrian period. It was named the Franconia Formation due to the first published documentation of exposures in vicinity of Franconia, Minnesota in the 1897 Ph.D. dissertation by Charles P. Berkley at the University of Minnesota titled Geology of the St. Croix Dalles. The Franconian stratigraphic stage was named after this formation.
The Burlington Limestone is a geologic formation in Missouri, Iowa and the Midwest region. It preserves fossils dating back to the Mississippian subperiod.
The Oread Limestone is a geologic unit of formation rank within the Shawnee Group throughout much of its extent. It is exposed in Kansas, Nebraska, Missouri, Oklahoma, and Iowa. The type locality is Mount Oread within Lawrence, Kansas. It preserves fossils of the Carboniferous period. Although it has significant shale members, its limestone members are resistant and form escarpments and ridges. Limestone from the unit is a historic building material in Kansas, particularly in the early buildings of the University of Kansas; standing examples include Spooner Hall and Dyche Hall.
The St. Louis Formation is a geologic formation in Iowa. It preserves fossils dating back to the Carboniferous period.
The Stanton Formation is a geologic formation of limestone in Iowa, Nebraska, Missouri and Kansas. It preserves fossils dating back to the Carboniferous period. It is in the Upper Pennsylvanian series, forming the top of the Lansing Group.
The Cummingsville Formation is a geologic formation in Iowa and Minnesota. It preserves fossils dating back to the Ordovician period.
The Windrow Formation is a geologic formation in Minnesota named after Windrow Bluff on Fort McCoy, Monroe County, Wisconsin. It preserves fossils dating back to the Cretaceous period.
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