Frenchman Formation

The Frenchman Formation is a stratigraphic unit of Late Cretaceous age in the Western Canada Sedimentary Basin. It is present in southern Saskatchewan and the Cypress [Hills (Canada)|Cypress Hills] of southeastern Alberta. The formation was defined by G.M. Furnival in 1942 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.

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 of a bird attributed to the genus Cimolopteryx has also been described from the Gryde locality.

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	Images
Acer-like	Indeterminate	GNP
Alnus	A. sp.	GNP
Araucarites	A. sp.	Chambery Coulee	Cone
Betula	B. sp.	GNP
Cercidiphyllum	C. sp.	Chambery Coulee, GNP
Cinnamomum-like	Indeterminate	Chambery Coulee, GNP		Likely not Cinnamomum.
Ficus?	Indeterminate	Chambery Coulee, GNP		Likely not in Moraceae.
Ginkgo	G. sp.	Chambery Coulee
Juglans	J. sp.	Chambery Coulee	Seeds
Macginitiea	M. sp.	Chambery Coulee, GNP
Magnolia	M. sp.	Chambery Coulee, GNP
Marmarthia	M. sp.	Chambery Coulee		A Lauraceae, similar to Lindera.
Menispermites	M. sp.	Chambery Coulee		Belongs to Menispermaceae.
Metasequoia	M. sp.	Chambery Coulee
Parataxodium?	Indeterminate	Chambery Coulee		In need of revision.
Platanus	P. sp.	Chambery Coulee, GNP
Populus	P. sp.	Chambery Coulee, GNP
Protophyllocladus	P. sp.	Chambery Coulee		Belongs to Podocarpaceae, similar to Phyllocladus.
Pseudoctenis	P. sp.	Chambery Coulee
Quercus	Q. sp.	Chambery Coulee
Rhus	R. sp.	Chambery Coulee, GNP
Sabalites	S. sp.	Chambery Coulee
Salix	S. sp.	Chambery Coulee, GNP
Sapindus	S. sp.	GNP
Sassafras	S. sp.	GNP
Sequoia	S. sp.	Chambery Coulee
Taxodium?	T?. sp.	Chambery Coulee
Zelkova	Z. sp.	Chambery Coulee