White Bluff Formation

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.

White Bluff Formation
Stratigraphic range: Paleogene
Type	Formation
Unit of	Jackson Group
Sub-units	Pastoria Sand Member, Caney Point Marl Member, Rison Clay Member
Lithology
Primary	marl, sand, clay
Location
Region	Arkansas
Country	United States
Type section
Named for	White Bluff, along the Arkansas River

Description

The White Bluff Formation is composed of three members: the Pastoria Sand Member, the Caney Point Marl Member, and the Rison Clay Member.^[1] The Pastoria Sand is a clayey sand containing glauconite and mollusca 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 fossils and scattered mollusca molds.^[1] The entire formation was deposited as a marine sequence.^[1][2]

See also

• Earth sciences portal
• United States portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Arkansas
• Paleontology in Arkansas