Unit Name: Frenchman Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Maastrichtian (70.6 - 65.5 ma)
Age Justification: The Frenchman is well known for its dinosaur fauna and has yielded abundant remains of Triceratops as well as amphibians and fish (Russell 1964, Russell 1967).
Province/Territory: Alberta; Saskatchewan
Originator: Furnival, 1942, 1946.
Along the valley of the Frenchman River in southwestern Saskatchewan, from west of Ravenscrag (Twp. 6, Rge. 24W3M), on the north side of the Frenchman River, to the east of Saskatchewan Highway 37 (Twp. 4, Rge.18W3M).
The Frenchman is recognizable only in the southwestern part of Saskatchewan and in the Cypress Hills of Alberta. The greatest thicknesses recorded are 113 m (371 ft) south of Elkwater, Alberta (Chi, 1966), and 70 m (230 ft) in the Frenchman River valley in Saskatchewan. Near Eastend the thickness is reduced to a few metres. The formation is thickest where pre-Frenchman erosion was deepest. The Frenchman is presumed to be present in eastern Saskatchewan beneath the beds of the Tertiary coal basin, but in core it is indistinguishable from deposits of the Whitemud and Eastend formations (Whitaker et al., 1978), and the combined formations attain a thickness of about 50 m (164 ft) in this area.
Coarse- to fine-grained, cross-bedded sands, in places cemented by calcium carbonate into ledges and concretions, interbedded with clays. The sand ranges in color from olive-green to greenish brown to yellow and buff, commonly stained yellow and brown at the surface; up to 30% of the sand size grains are volcanic fragments and the rocks are volcanic litharenites (Misko and Hendry, 1979). Lenses of clay-pebble conglomerate are common in the sands, and in places at the base of the formation the sands contain well-rounded quartzite pebbles or a bed of pebble conglomerate (Sutherland, 1977). The clays are olive-green, grey brown, and purplish brown, and form areas of badlands along the valley of Frenchman River. The sands and clays in the Frenchman Formation are arranged in a series of well defined upward-fining sequences with erosive bases (Sutherland, 1977). Both the sands and the clays are present over all of the area where the Frenchman occurs, but the thickest clays are found in the Frenchman River valley immediately to the east and west of Saskatchewan Highway 37, where the formation attains its greatest thickness. Both the sands and clays have yielded remains of ceratopsian dinosaurs.
The lower contact of the Frenchman is erosional, and with increasing depth of erosion it is with purple clays of the Battle Formation, kaolinitic clays and sands of the Whitemud Formation, yellow sands of the Eastend Formation and grey clays of the Bearpaw Formation. Greatest depths of erosion occur near the town of Elkwater, Alberta, northeast of Eastend along the valley of Swift Current Creek, and southeast of Eastend along the Frenchman River valley. The upper contact with the Paleocene Ravenscrag Formation is conformable, and is drawn arbitrarily at the base of the "Ferris" or "No. 1" coal seam. Lateral relationships of other units with the Frenchman Formation are difficult to establish except in a general way according to geologic age. The Frenchman is correlative with the upper part of the Brazeau Formation in the central foothills of Alberta, the lower part of the Willow Creek Formation in the Oldman River region, and the Willow Creek facies of the Paskapoo Formation in the Bow River and Red Deer River regions (Irish, 1970). Carrigy (1970) suggested that use of the term Frenchman be restricted to Saskatchewan, so that beds formerly assigned to the Frenchman in the Alberta part of the Cypress Hills, and correlative with the Frenchman Formation of Saskatchewan, would belong to the lower part of the Ravenscrag Formation. The Frenchman Formation is equivalent to the Hell Creek Formation of Montana and North Dakota.
Beds of the Frenchman Formation have been assigned to the lower portion of the B-division of the "Lignite Tertiary" (Dawson, 1875), the Laramie Formation (McConnell, 1885), the Lance Formation (Rose, 1916), the Ravenscrag Beds of the Fort Union (Davis, 1918), the Ravenscrag Formation (Williams and Dyer, 1930), and the lower Ravenscrag Formation (McLearn, 1929, 1930; Fraser et al., 1935). The Frenchman Formation of Furnival (1946) is equivalent to the lower Ravenscrag of McLearn (1929, 1930) and Fraser et al. (1935). As used by Kupsch (1956, 1957) in the area around Eastend, Saskatchewan the Frenchman includes the Battle Formation of other authors. Carrigy (1970, 1971), echoing a suggestion of Russell (1950), has proposed that, because of difficulty of correlation the usage of Frenchman be restricted to Saskatchewan, and that in Alberta the Ravenscrag Formation should include all strata down to the contact with the Battle Formation. Obsolete Names: Previously named the lower Ravenscrag, but renamed Frenchman Formation by Furnival (1946).
Carrigy, 1970, 1971; Chi, 1966; Davis, 1918; Dawson, 1875; Fraser et al., 1935; Furnival, 1942, 1946; Irish, 1970; Kupsch, 1956, 1957; McConnell, 1885; McLearn, 1929, 1930; Misko and Hendry, 1979; Rose, 1916; Russell, 1950, 1964, 1967; Sutherland, 1977; Whitaker et al., 1978; Williams and Dyer, 1930.
Furnival, G.M., 1942. Preliminary Map, Cypress Lake, Saskatchewan; Geological Survey of Canada, Paper 42-5, contains Preliminary Map 42-5, Cypress Lake, West of Third Meridian, Saskatchewan, Scale: 1 inch to 2 miles.
Furnival, G.M., 1946. Cypress Lake map-area, Saskatchewan; Geological Survey of Canada, Memoir 242, 161 p. contains "A" Series Map 784A, Cypress Lake, West of Third Meridian, Saskatchewan, Scale: 1:253 440 or 1 Inch to 4 Miles and "A" Series Map 856A, Structure-Contours, Cypress Lake, West of Third Meridian, Saskatchewan, Structure-contour interval 50 feet, Scale: 1:253 440 or 1 Inch to 4 Miles.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: H.E. Hendry
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 05 Mar 2010