The Shakopee Formation is a geologic formation in Illinois, Indiana, Wisconsin, and Minnesota. It preserves fossils dating back to the Ordovician period. It is named after the town of Shakopee, Minnesota, where the formation can be seen in bluffs along the Minnesota River
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 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 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 Jackson Formation is a geologic formation in Tennessee. It preserves fossils dating back to the Paleogene period. Exposed only in bluffs along Mississippi River with thickness at least 60 feet. Primary rock type is sand. Secondary rock type is clay or mud. Other rock types include slit and lignite. "Light gray to buff, medium- to very fine-grained silty sand, interbedded with light gray clayey silt." From the Tertiary geological age.
The Rhems Formation, also called the Rhems Shale, is a geologic formation in South Carolina. The Rhems Formation is considered part of the Black Mingo Group. It was named after Rhems, SC which is located five miles from the type locality at Perkins Bluff. The unit is a light gray to black shale interlaminated with thin seams of fine-grained sand and mica with some layers partially silicified. It preserves fossils dating back to the Paleogene period.
The Alum Bluff Group is a geologic group in the states of Georgia, Florida, and Alabama. It preserves fossils dating back to the Neogene 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 Red Bluff Clay is a geologic formation in Alabama. It preserves fossils dating back to the Paleogene period.
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 Weches Formation is a greensand, slay, and shale geologic formation in Louisiana and Eastern Texas. It preserves fossils dating back to the Paleogene period, specifically the Eocene.
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 Marlbrook Marl is a geologic formation in Arkansas. 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 Johns Valley Formation is a geologic formation in Arkansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.
The Corsicana Marl is a geologic formation in Texas. It preserves fossils dating back to the Cretaceous period. It is primarily consisted of clay and mud, while a secondary rock type being sandstone.
The August Town Formation is a geologic formation in Jamaica. It preserves fossils dating back to the Neogene period.
The Selborne Group is a geologic group in England. It preserves fossils dating back to the Cretaceous period. It comprises the Gault Formation and the overlying Upper Greensand Formation.
Arkansas 
United States 
