Unit Name: Ravenscrag Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Late Cretaceous - Tertiary (99.6 - 1.806 ma)
Age Justification: The lower Ravenscrag is well known for its dinosaur fauna, which includes abundant Triceratops as well as amphibians and fish.
Originator: Davis, 1918; Fraser et al., 1935.
Ravenscrag Butte, southeastern Saskatchewan. Upper Ravenscrag (Ravenscrag Formation) Tertiary, Paleocene
The upper Ravenscrag ranges from 162 to about 244 m (530 to about 800 ft) in thickness. It is present, where not eroded, in southwestern Saskatchewan in the Eastend-Cypress Hills area.
Buff, grey and white sandy clays, with sandstones, shales and coal.
The unit is overlain by the Eocene Swift Current Creek beds and underlain by the Upper Cretaceous lower Ravenscrag Formation. Lower Ravenscrag (Frenchman Formation) Upper Cretaceous Lithology: Massive, cross-bedded, medium to fine grained sandstones, grey to greenish grey weathering to yellowish or yellowish green. Clay pellets are present and the sands are occasionally dolomitic or calcareous. Thickness and Distribution: The lower Ravenscrag ranges from 6 to 58 m (20 to 190 ft) in thickness. It is present in the Eastend-Cypress Hills area, southeastern Saskatchewan. Relationship to Other Units: The unit is conformably overlain by the Paleocene upper Ravenscrag and underlain by the Upper Cretaceous Battle, Whitemud, Eastend or Bearpaw formations at an erosional contact. The lower Ravenscrag is equivalent to the Hell Creek Member of the Lance Formation of Montana, the upper part of the Brazeau Formation of the central Alberta Foothills, the lower part of Willow Creek Formation in the Oldman River area of southwestern Alberta, and the Willow Creek Facies of the Paskapoo Formation in the Bow and Red Deer River areas, Alberta.
Mapped as Estevan by Davis (1918 as Ravenscrag beds, as Fort Union by Rose (1916), and as upper Laramie by McConnell (1885). The Willowbunch Member of McLearn (1930) is part of the upper Ravenscrag.
Davis, 1918; Fraser et al., 1935; Furnival, 1950; Williams and Dyer, 1930.
Davis, N.B., 1918. Report on the clay resources of southern Saskatchewan; Canada, Department of Mines, Mines Branch, Report 468, 93 p.
Fraser, F.J., McLearn, F.H., Russell, L.S., Warren, P.S., and Wickenden, R.T.D., 1935, Geology of southern Saskatchewan, Geological Survey of Canada, Memoir 176, 137 pp.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: ASPG Lexicon 1960
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 May 2008