National Geologic Map Database

Geologic Unit: Dakota


Dakota Sandstone (AZ*,CO*,IA*,KS*,MN*,MT*,NE*,NM*,ND*,OK*,SD*,TX*,UT*,WY*)
Dakota Formation (IA,KS*,MN*,NE*,NM*,SD,UT*,WY)
Dakota Conglomerate (UT*)
Dakota Group (CO*,KS*,NE*,NM,ND)


GROUP STATUS (alphabetical): Cedar Mountain Formation (CO) or Cedar Mountain Shale (CO), Fall River Formation (ND) or Fall River Sandstone (NE), Fuson Formation (ND) or Fuson Shale (NE), informal J sand or J sandstone (CO,NE,WY), Lakota Formation (NE,ND), Lytle Formation (CO*), Mesa Rica Sandstone (NM), Mowry Formation (ND), Muddy Sandstone (CO,WY), Naturita Formation (CO), Newcastle Formation (ND) or Newcastle Sandstone (NE), Omadi Sandstone (CO,KS,NE*,WY) or Omadi Formation (CO,KS,NE,WY), Pajarito Formation (NM), Plainview Formation (CO), Romeroville Sandstone (CO,NM,OK), Skull Creek Formation (ND) or Skull Creek Shale (CO,NE), South Platte Formation (CO*,WY*).
FORMATION STATUS (alphabetical): Cubero Tongue (NM*), Dry Creek Canyon Member (CO*), Encinal Canyon Member (NM*), Janssen Clay Member (KS*), Nishnabotna Member (IA,MN?,NE?,SD?), Oak Canyon Member (NM*), Paguate Tongue (NM*), Terra Cotta Clay Member (KS*), Twowells Member (NM) or Twowells Tongue (AZ*,NM*), White Rock Mesa Member (CO,NM), Whitewater Arroyo Shale Member (NM), Woodbury Member (IA,MN?,NE?,SD?).

Geologic age:

early Late Cretaceous (Cenomanian)*; locally late Early Cretaceous (Albian)*

Type section, locality, area and/or origin of name:

Occurs in hills in back of town of Dakota, Dakota Co., NE. Extensively developed in Dakota Co. [NE] below mouth of Big Sioux River, thence south into northeastern KS and beyond. Named from town of Dakota (Meek and Hayden, 1862).
Type locality: in Missouri River Bluffs, 1 mi southeast of Homer, in NE/4 sec. 13, T. 27 N., R. 4 E., Dakota Co., NE (Condra and Reed, 1943).
Type locality of group: about 2 mi north of Bellevue, Larimer Co., CO (Lee, 1923).

AAPG geologic province:

Basin-and-Range province*
Black Mesa basin*
Central Kansas uplift*
Denver basin*
Eagle basin*
Green River basin*
Iowa shelf*
Las Animas arch*
Las Vegas-Raton basin*
North Park basin
Orogrande basin*
Palo Duro basin*
Paradox basin*
Piceance basin*
Plateau sedimentary province*
Powder River basin*
San Juan basin*
Sierra Grande uplift*
Sioux uplift*
South Park basin*
Sweetgrass arch*
Uinta basin*
Williston basin*

For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).