Belle Fourche Formation Explained

Belle Fourche Formation
Type:	Formation
Age:	Cretaceous
Region:	Montana, North Dakota, South Dakota, Wyoming
Country:	United States

The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota.^[1]

The unit records the gradual opening and expansion of the Greenhorn Cycle of the Western Interior Seaway, and as such is lithologically identical to the Graneros Shale Formation (that is, it is the same formation under a different name).^[2]

See also

• List of fossiliferous stratigraphic units in Montana
• Paleontology in Montana
• Paleontology in North Dakota
• Paleontology in South Dakota
• Paleontology in Wyoming

References

1. Web site: Geologic Unit: Belle Fourche . Geolex — Unit Summary . National Geologic Database . United States Geological Survey . 2018-06-29 .
2. . KGS--Graneros Shale in Central Kansas--Stratigraphy . 178 . Kansas Geological Survey Bulletin . . 1965. Stratigraphy / Graneros Shale / Name and Definition . The lithologic equivalent of the Graneros in the Black Hills and surrounding areas is the Belle Fourche Shale. Considerable similarity exists between these two formations, and, if the name Graneros is to be perpetuated in the Black Hills region, it would be best used to replace the name Belle Fourche over which the former has priority. . September 6, 2021 .

• Web site: Fossilworks: Gateway to the Paleobiology Database. ((Various Contributors to the Paleobiology Database)). 17 December 2021.