| Morrow Group Stratigraphic range: Pennsylvanian | |
|---|---|
| Type | Group |
| Sub-units | Bloyd Formation, Hale Formation |
| Underlies | Atoka Formation |
| Overlies | Pitkin Formation |
| Location | |
| Region | Arkansas |
| Country | United States |
| Type section | |
| Named for | Morrow, Washington County, Arkansas |
| Named by | George Irving Adams and Edward Oscar Ulrich [1] |
The Morrow Group was a geologic group in Arkansas that is now abandoned and replaced by the Bloyd Formation and the Hale Formation. It preserves fossils dating back to the Pennsylvanian period.
The Claiborne Formation or Claiborne Group is a geologic formation in Arkansas, Illinois, Kentucky, and Texas. It preserves fossils dating back to the Paleogene period.
The Batesville Sandstone is a geologic formation in northern Arkansas that dates to the Chesterian Series of the late Mississippian. The base of the Batesville Sandstone, named the Hindsville Limestone Member, unconformably lies on the Moorefield Formation.
The Moorefield Formation, or Moorefield Shale, is a geologic formation in northern Arkansas and eastern Oklahoma that dates to the Meramecian Series of the middle Mississippian. In Arkansas, this formation is generally recognized to have one member, the Ruddell Shale, in the upper Moorefield Formation.
The Pitkin Formation, or Pitkin Limestone, is a fossiliferous geologic formation in northern Arkansas that dates to the Chesterian Series of the late Mississippian. This formation was first named the "Archimedes Limestone" by David Dale Owen in 1858, but was replaced in 1904. The Pitkin conformably overlies the Fayetteville Shale and unconformably underlies the Pennsylvanian-age Hale Formation. Some workers have considered the top of the Pitkin Formation to be a separate formation called the Imo Formation. However more recently, others have considered it as an informal member of the Pitkin Formation.
The Arkadelphia Marl is a geologic formation in Arkansas in Clark, Nevada, and Hempstead counties. It preserves fossils dating back to the Cretaceous period.
The Brownstown Marl is a geologic formation in Arkansas. It preserves fossils dating back to the Cretaceous period.
The De Queen Formation, formerly known as the DeQueen Limestone Member is a Mesozoic geological formation located in southwestern Arkansas and southeastern Oklahoma in the United States. Fossil sauropod and theropod tracks have been reported from the formation. It preserves fossils dating back to the Cretaceous period, particularly the Albian age.
The Nacatoch Formation is a geologic formation in Arkansas, USA. It preserves fossils dating back to the Cretaceous period.
The Nacatoch Sand is a geologic formation in Arkansas. It preserves fossils dating back to the Cretaceous period.
The Holly Creek Formation is a geologic formation in Arkansas. It preserves fossils dating back to the Cretaceous period.
The Everton Formation is a geologic formation in northern Arkansas that dates to the middle Ordovician Period. Unconformities separate this formation from the underlying Powell Formation and the overlying St. Peter Sandstone Formation. Named for the town of Everton in Boone County, Arkansas in 1907, the Everton Formation is composed primarily of dolomite, limestone, and sandstone.
The Smithville Formation or Smithville Dolomite is a geologic formation in Arkansas. It preserves fossils dating back to the Ordovician period.
The Theodosia Formation is a geologic formation in Missouri. It preserves fossils dating back to the Ordovician period.
The St. Clair Limestone is a geologic formation in Arkansas, Indiana, Missouri, and Oklahoma. It preserves fossils dating back to the Silurian period. This high density, high magnesium dolomitic limestone was originally classified as a marble in Oklahoma due to the fact that it would hold a high polish, hence Marble City.
The White Bluff Formation is a marl, sand, and clay geologic formation in Arkansas that is part of the Jackson Group. It preserves fossils dating back to the Paleogene period, specifically the Eocene.
The Jefferson City Formation or Jefferson City Dolomite is a geologic formation in the Ozarks of Missouri and Arkansas. The Jefferson City is in part not differentiated from the Cotter Formation of northern Arkansas. It preserves fossils dating back to the Ordovician period.
The Winslow Formation was a geologic formation in Arkansas, now abandoned and replaced by the Atoka Formation, the Hartshorne Formation, and the lower McAlester Formation. It preserves fossils dating back to the Carboniferous period.
The Hartshorne Formation is a geologic formation in Arkansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.
The Boggy Formation is a geologic formation in Arkansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.
The Kiamichi Shale or Kiamichi Formation is a geologic formation in Arkansas and Texas. It preserves fossils dating back to the Cretaceous period.
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