| Weches Formation Stratigraphic range: Paleogene | |
|---|---|
| Type | Formation |
| Lithology | |
| Primary | sandstone, shale, clay |
| Other | marl, limestone |
| Location | |
| Region |  Louisiana,  Texas |
| Country |  United States |
The Weches Formation is a greensand, slay, and shale geologic formation in Louisiana and Eastern Texas. [1] [2] It preserves fossils dating back to the Paleogene period, specifically the Eocene.
The Weches Formation is a fossiliferous glauconite rich sand that graduates into a clay. [2] It is considered one of the principal iron bearing beds in Eastern Texas, and is mined for sand in gravel in parts of Texas where exposed. [2] [3] The Weches Formation was originally called the Weches Greensand, and was considered a member of the Mount Selman Formation before being raised to formation status. [2] [4]
The Wilcox Group is an important geologic group in the Gulf of Mexico Basin and surrounding onshore areas from Mexico and Texas to Louisiana and Alabama. The group ranges in age from Paleocene to Eocene and is in Texas subdivided into the Calvert Bluff, Simsboro and Hooper Formations, and in Alabama into the Nanafalia and Hatchetigbee Formations. Other subdivisions are the Lower, Middle and Upper Wilcox Subgroups, and the Carrizo and Indio Formations.
The Warsaw Formation is a geologic formation in Illinois, Iowa and Missouri. It preserves fossils dating back to the Mississippian subperiod.
The Belgrade Formation is a limestone geologic formation in North Carolina characterized by limestone coquina mixed with sand, and thinly laminated clays. It preserves fossils dating back to the Paleogene period.
The River Bend Formation is a limestone geologic formation in North Carolina. It preserves fossils dating back to the Paleogene period.
The Castle Hayne Limestone is a geologic formation in North Carolina. It consists of cobble to pebble sized clasts, usually rounded, coated with phosphate and glauconite in a limestone matrix. The Castle Hayne Limestone is known for containing fossils dating back to the Paleogene period. It preserves many of North Carolina's renowned Eocene fossils. It is named after the locality of Castle Hayne in New Hanover county, though the formation itself stretches over several counties.
The Powell Formation or Powell Dolomite is a geologic formation in northern Arkansas, southeast Missouri and Virginia. It contains gastropod, cephalopod, and trilobite fossils dating back to the Ordovician Period.
The Cotter Formation is a geologic formation in Arkansas, Missouri, Oklahoma and in Virginia. It preserves fossils dating back to the Ordovician period.
The Patapsco Formation is a geologic formation of varigated clays, sandy clays, and sand in Virginia, the District of Columbia, Maryland, Delaware, Pennsylvania, and in the subsurface of New Jersey. It preserves fossils such as plants and molluscs dating back to the Cretaceous period.
The Fernvale Limestone is a geologic formation in Alabama, Arkansas, Illinois, Missouri, Oklahoma, and Tennessee. It preserves fossils dating back to the Ordovician period.
The Tallahatta Formation is a geologic formation found on the surface in Alabama, Florida, Georgia, and Mississippi. It is also located in the subsurface of Kentucky. The Tallahatta formation is part of the Claiborne Group and contains four members: the Basic City Shale in Mississippi, the Holy Springs Sand Member in Mississippi, the Meridian Sand Member in Alabama and Mississippi, and the Neshoba Sand Member in Mississippi. It preserves fossils dating back to the Paleogene period, specifically the Eocene.
The Hatchetigbee Bluff Formation is a geologic formation in Alabama, Georgia, Louisiana and Mississippi. The youngest unit of the Wilcox Group preserves fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification. The formation is named for Hatchetigbee Bluff on the Tombigbee River, Washington County, Alabama.
Yazoo Clay is a clay geologic formation in Alabama, Louisiana, and Mississippi. It was named after a bluff along the Yazoo River at Yazoo City, Mississippi It contains is a type of clay known as montmorillonite, making it a poor foundation material due to the fact that moisture causes extreme changes in volume. Sand, pyrite, and marl have all been noted in the formation. It preserves fossils from the Eocene, including the prehistoric cetacean Basilosaurus.
The Winona Formation is a sand geologic formation in Mississippi. It preserves fossils dating back to the Paleogene period.
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 Fern Glen Formation is a geologic formation in eastern and southeastern Missouri. It preserves fossils dating back to the Osagean Series of the Mississippian subperiod.
The Viola Formation is a geologic formation in Oklahoma. It preserves fossils dating back to the Ordovician period.
The Whitehorse Formation is a geologic formation in Nebraska and Oklahoma. It preserves fossils dating back to the Permian period.
The La Jolla Group is a group of geologic formations in coastal southwestern San Diego County, Southern California. Its locations include the coastal La Jolla San Diego region.
The Otay Formation is a geologic formation in San Diego County, California and northern Baja California state (Mexico). It is within the Peninsular Ranges province.
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