The Frenchman Formation is a stratigraphic unit of Late Cretaceous (late Maastrichtian) age in the Western Canada Sedimentary Basin. It is present in southern Saskatchewan and the Cypress Hills of southeastern Alberta. The formation was defined by G.M. Furnival in 1942Furnival, 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. from observations of outcrops along the Frenchman River, between Ravenscrag and Highway 37. It contains the youngest of dinosaur genera, much like the Hell Creek Formation in the United States.
Lithology
The Frenchman Formation consists of olive-green to brown, fine- to coarse-grained, cross-bedded sandstone with interbedded claystone bands and minor beds and lenses of intraformational clay-clast conglomerate. A conglomerate layer with well-rounded quartzite pebbles is present above the basal unconformity in some areas.Glass, D.J., editor, 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada. Canadian Society of Petroleum Geologists, Calgary, Alberta, 1423 p. on CD-ROM, .
Thickness and distribution The Frenchman Formation is present in southwestern Saskatchewan and the Cypress Hills area of southeastern Alberta. Its maximum reported thickness is about 113 m.
Age
The Frenchman Formation is of latest Maastrichtian age, and the top of the formation coincides with the Cretaceous-Paleogene boundary, as evidenced by biostratigraphic changes and, in some areas, the presence of the terminal Cretaceous iridium anomaly.
Relationship to other units
Although some early workers included the Frenchman Formation in the overlying Ravenscrag Formation, the two are separated by the Cretaceous-Paleogene boundary and are now treated separately. The contact is abrupt but conformable, and occurs at the base of the No. 1 or Ferris coal seam of the Ravenscrag Formation.
The Frenchman is separated from the underlying formations by an erosional unconformity, and depending on the depth of the erosion, the Frenchman rests on the Whitemud Formation, the Battle Formation, the Eastend Formation, or the Bearpaw Formation. It is equivalent in age to the lower part of the Scollard Formation, the lower part of the Willow Creek Formation, the lower part of the Coalspur Formation in Alberta, and the Hell Creek Formation in Montana and North Dakota.
Paleontology Mammals and birds
J.E. Storer described fossil mammals from the Gryde locality in the Frenchman Formation, including Parectypodus and Alphadon. A bone (the humeral end of the left coracoid) of a bird attributed to the genus Cimolopteryx has also been described from the Gryde locality.
Dinosaurs Dinosaurs reported from the Frenchman Formation Genus Species Location Stratigraphic position Material Notes ImagesAnkylosaurusA. magniventrisAn ankylosaurine ankylosauridcf. Anzucf. A. sp.Two manual ungualsClaws from a large caenagnathid, tentatively referred to Anzu based on size?Dromaeosaurus?D. sp.Scotty siteThree teethSome teeth are up to 3 cm in length.EdmontosaurusE. annectens"Complete skull, [three or four] partial skulls""Table 20.1," in Weishampel, et al. (2004). Page 440.A hadrosauridE. saskatchewanensisJunior synonym of E. annectensCampione, N.E. and Evans, D.C. (2011). "Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America." PLoS ONE, 6(9): e25186. LeptorhynchosL. sp.A partial skeletonA caenagnathid theropod Ornithomimus Ornithomimus sp. Sphaerotholuscf. S. buchholtzae"Nearly complete left postorbital"The first pachycephalosaurid reported from the Frenchman FormationThescelosaurusT. assiniboiensisNearly complete skeletonTorosaurusT. sp.FrillA large chasmosaurine ceratopsian distinct from Triceratops. Fossils have also been unearthed in the Scollard Formation.Tokaryk, T. 1986. Ceratopsian dinosaurs from the Frenchman Formation (Upper Cretaceous) of Saskatchewan. Canadian Field-Naturalist 100:192–196.TriceratopsT. prorsusRedpath, Saskatchewan Nearly complete skull, one other partial skull Being one of the most popular dinosaurs, they are widely known.TyrannosaurusT. rexNearly complete skeleton"Scotty", possibly the largest T. rex ever discovered, is from the Frenchman Formation.
Plants Two megafloral assemblages were collected from Grasslands National Park and the Chambery Coulee site. The differences in floral composition as well as evidence of forest fires indicated these two localities represented an ecological succession in a fire-disturbed environment, with burned mature forests being colonised by pioneer shrubs and then a subsequent reestablishment of coniferous and hardwood forest. Leaf analysis estimated mean annual temperatures of in a largely deciduous mixed forest of temperate climate.
Taxa Species Locality Material Notes ImagesAcer-likeIndeterminate GNPAlnusA. sp. GNPAraucarites A. sp. Chambery CouleeConeBetulaB. sp. GNPCercidiphyllumC. sp. Chambery Coulee, GNPCinnamomum-likeIndeterminate Chambery Coulee, GNPLikely not Cinnamomum.Ficus?IndeterminateChambery Coulee, GNPLikely not in Moraceae.GinkgoG. sp. Chambery CouleeJuglans J. sp. Chambery CouleeSeedsMacginitiea M. sp. Chambery Coulee, GNPMagnoliaM. sp. Chambery Coulee, GNPMarmarthiaM. sp. Chambery CouleeA Lauraceae, similar to Lindera.MenispermitesM. sp. Chambery CouleeBelongs to Menispermaceae. Metasequoia M. sp. Chambery CouleeParataxodium?Indeterminate Chambery CouleeIn need of revision.PlatanusP. sp. Chambery Coulee, GNPPopulusP. sp. Chambery Coulee, GNPProtophyllocladusP. sp. Chambery CouleeBelongs to Podocarpaceae, similar to Phyllocladus.PseudoctenisP. sp. Chambery CouleeQuercus Q. sp. Chambery CouleeRhusR. sp. Chambery Coulee, GNPSabalitesS. sp. Chambery CouleeSalixS. sp. Chambery Coulee, GNPSapindusS. sp. GNPSassafrasS. sp. GNPSequoiaS. sp. Chambery CouleeTaxodium?T?. sp. Chambery CouleeZelkovaZ. sp. Chambery Coulee
See also
List of dinosaur-bearing rock formations
References