Unit Name: Gypsum Spring Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Middle Jurassic (175.6 - 161.2 ma)
Province/Territory: Manitoba; Saskatchewan; Montana; North Dakota; Wyoming

Originator: Love, J.D., 1939.

Type Locality:
Freemont County, Wyoming, near Gypsum Spring and Red Creek.

Lithology:
Lower part comprises 15.2 to 38 m (50 to 125 ft) of massive white gypsum overlying a bed of red sandy shale. The upper part is composed of beds of gypsum alternating with red shale, dolomite and fossiliferous limestone. The formation is about 76 m (250 ft) thick in central Wyoming.

Relationship:
Traced into Saskatchewan from the Black Hills, it is correlatable with the upper member of the Watrous Formation and the lower member of the Gravelbourg Formation (Francis, 1956). The name is not in general usage in Canada.

Other Citations:
Francis, 1956; Imlay, Gardiner, Rodgers, and Hadley, 1948; Love, 1939.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: J.E. Christopher
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 20 May 2004