Hell Creek Formation

Gray sand, silt, clay, and sandstone; river sediment; as thick as 150 metres (500 feet).
State North Dakota
Name Hell Creek Formation
Geologic age Upper Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Siltstone (Bed)poorly consolidated
Sedimentary > Clastic > Sandstone (Bed)poorly consolidated
Sedimentary > Clastic > Mudstone > Claystone (Bed)poorly consolidated
Incidental
Sedimentary > Clastic > Mudstone > Claystone > Bentonite (Bed)ND003 - beds tend to be lignitic or bentonitic and typically poorly consolidated.
Sedimentary > Coal > Lignite (Bed)ND003 - beds tend to be lignitic or bentonitic and typically poorly consolidated.
Comments Map unit descriptions mix unconsolidated and sedimentary terms; using sedimentary terms with poorly consolidated according to other sources.
References

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.

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/

https://ngmdb.usgs.gov/Geolex/search

NGMDB product
Counties Bottineau - Bowman - Burleigh - Emmons - Grant - Kidder - Logan - McHenry - McIntosh - McLean - Morton - Pierce - Renville - Rolette - Sheridan - Sioux - Slope - Ward - Wells