The White Bluff Formation is a marl, sand, and clay

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

that is part of the

Jackson Group The Jackson Group is a geologic group in Arkansas and North Carolina. It preserves fossils dating back to the Paleogene to Neogene period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuati ...

. It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

dating back to the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

period, specifically the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

Description

The White Bluff Formation is composed of three members: the Pastoria Sand Member, the Caney Point Marl Member, and the Rison Clay Member. The Pastoria Sand is a clayey sand containing glauconite and

mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

fossils. The Caney Point Marl is a chalky clay with glauconite and various invertebrate fossils. The Rison Clay is a clay with interbedded silts containing

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...

fossils and scattered mollusca molds. The entire formation was deposited as a marine sequence.

References

* Paleogene Arkansas {{Paleogene-stub

Description

See also

References