Chadron Formation
Stratigraphic range: Late Eocene ~35–34 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Chadron Formation in Badlands National Park, South Dakota
Type	Geological formation
Unit of	White River Formation
Underlies	Brule Formation
Overlies	marine indet.
Lithology
Primary	Fine grained clastic rocks
Other	Tuff, Sandstone
Location
Region	Nebraska, Wyoming, North Dakota, South Dakota
Country	United States
Type section
Named for	Chadron, Nebraska

Chadron Formation is a rock formation in North Dakota, South Dakota, northwestern Nebraska, and eastern Wyoming. It is named after the town of Chadron, Nebraska. It was mapped out by Carl Vondra in the 1950s.^[1]

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