| Oregon Formation | |
|---|---|
| Stratigraphic range: Ordovician | |
| Type | Formation |
| Underlies | Tyrone Limestone |
| Overlies | Camp Nelson Limestone |
| Location | |
| Region | Southeastern United States |
| Country | United States |
| Extent | Kentucky |
The Oregon Formation is a geologic formation in Kentucky. It dates back to the Ordovician period .
Flexicalymene Shirley, 1936. is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and Family Calymenidae. Flexicalymene specimens can be mistaken for Calymene, Gravicalymene, Diacalymene and a few other Calymenina genera. They are used as an index fossil in the Ordovician. Ohio and North America are particularly known for being rich with Flexicalymene fossils.
The Arnheim Formation is a geologic formation in Ohio. It preserves fossils dating back to the Ordovician period.
The Grant Lake Formation is a geologic formation in Ohio and Kentucky. It preserves fossils dating back to the Ordovician period.
The Bull Fork Formation is a geologic formation in north central Kentucky and southwestern Ohio. It preserves fossils dating back to the Ordovician period.
The Bellevue Formation is a geologic formation in Ohio and Kentucky. It preserves fossils dating back to the Ordovician period.
The McMillan Formation is a geologic formation in Ohio, Kentucky and Indiana. It preserves fossils dating back to the Ordovician period.
The Ashlock Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Benbolt Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Calloway Creek Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Drakes Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Tyrone Limestone is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Leipers Limestone is a geologic formation in Kentucky, Tennessee, Alabama and Georgia. It preserves fossils dating back to the Ordovician Period.
The Lexington Limestone is a prominent geologic formation that constitutes a large part of the late Ordovician bedrock of the inner Bluegrass region in Kentucky. Named after the city of Lexington, the geologic formation has heavily influenced both the surface topography and economy of the region.
The Reba Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Stingy Creek Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Tate Formation is a geologic formation in Kentucky. It preserves fossils dating back to the Ordovician period.
The Black River Group is a geologic group that covers three sedimentary basins in the Eastern and Midwestern United States. These include the Appalachian Basin, Illinois Basin and the Michigan Basin. It dates back to the Late Ordovician period. It is roughly equivalent to the Platteville Group in Illinois. In Kentucky and Tennessee it is also known as the High Bridge Group. In areas where this Geologic Unit thins it is also called the Black River Formation (undifferentiated). One example of this is over the Cincinnati Arch & Findley Arch. Large parts of the Black River have been dolomized (where the parent limestone CaCO3 has been turned into dolomite CaMg(CO3)2.) This happed when there was interaction of hot saline brine and the limestone. This created hydrothermal dolomites that in some areas serve as petroleum reservoirs.
The Camp Nelson Limestone is a geologic formation in Kentucky. It dates back to the Ordovician period.
The Garrard Siltstone is a geologic formation in Kentucky. It dates back to the Ordovician period.
The Cumberland Formation is a geologic formation in Kentucky. It dates back to the Ordovician period.
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