Golden Valley Formation

The Golden Valley Formation in western North Dakota preserves a broad swampy lowland landscape from the transition between the Late Paleocene and Early Eocene, around the time of the Paleocene-Eocene Thermal Maximum. Named in 1947 for the city of Golden Valley, it survives as scattered outliers in the Williston Basin and consists of the lower Bear Den Member and upper Camels Butte Member. Its claystone, mudstone, sandstone, lignite, and conglomerate contain abundant fossils of wetland plants, freshwater mollusks, insects, fish, amphibians, turtles, lizards, crocodilians, and early mammals. This rich record makes it important for understanding environmental change, early Cenozoic ecosystems, and subtropical wetlands in the northern Great Plains.

North Dakota · United States