White River Group

Brule Formation: pinkish siltstone, clay and sand; river and lake sediment; as thick as 50 metres (150 feet). Chadron Formation: light-colored sand with quartzite and porphyry pebbles, overlain by dark clay; river and lake sediment; as thick as 30 metres (100 feet).
State North Dakota
Name White River Group
Geologic age Oligocene
Lithologic constituents
Sedimentary > Clastic > Mudstone > Claystone (Bed)poorly consolidated
Sedimentary > Clastic > Sandstone (Bed)poorly consolidated
Sedimentary > Clastic > Siltstone (Bed)poorly consolidated
Comments Map unit descriptions mix unconsolidated and sedimentary terms; using sedimentary terms with poorly consolidated according to other sources.
Stratigraphic units Brule Formation, Chadron Formation

North Dakota Geological Survey, 2001, Geologic Bedrock Map of North Dakota based on Bluemle, John P., 1983, Geologic and Topographic Bedrock Map of North Dakota, NDGS Miscellaneous Map 25, 1:670,000 scale.

Clausen, E. N., and Kihm, A. J., eds., 1986, Tertiary and Upper Cretaceous of south-central and western North Dakota Field Trip Guidebook, North Dakota Geological Society.

NGMDB product
Counties Billings - Dunn - Golden Valley - Hettinger - Slope - Stark