Frenchman Formation

The Frenchman Formation is a special layer of rock from the time of the Late Cretaceous, a very long time ago, found in parts of southern Saskatchewan and the Cypress Hills in southeastern Alberta. This rock layer was first described in 1942 by a scientist named G.M. Furnival. He studied rocks along the Frenchman River, between places called Ravenscrag and near Highway 37.

One of the most exciting things about the Frenchman Formation is that it holds fossils from some of the youngest dinosaurs that ever lived. This makes it very important for scientists who study dinosaurs, just like another famous rock layer called the Hell Creek Formation in the United States. These fossils help us learn about the world right before the time when dinosaurs lived ended. The formation is part of a larger area known as the Western Canada Sedimentary Basin, which contains many layers of rock that tell stories about Earth’s past. It is also an important stratigraphic unit for understanding the age of the Late Cretaceous, especially the late Maastrichtian time period.

Lithology

The Frenchman Formation is made up of olive-green to brown sandstone that ranges from fine to coarse grains and has layers of claystone mixed in. There are also small sections of conglomerate, which contain pieces of quartzite pebbles, especially above the base in certain areas.

Thickness and distribution

The Frenchman Formation can be found in southwestern Saskatchewan and the Cypress Hills area of southeastern Alberta. The thickest part of this formation is about 113 meters.

Age

The Frenchman Formation is from the very end of the Maastrichtian age, which was part of the Late Cretaceous period. The top of this formation marks the Cretaceous-Paleogene boundary. This important boundary shows changes in tiny fossils and, in some places, includes a layer with a special type of element called an iridium anomaly, helping scientists understand major events from Earth's past.

Relationship to other units

The Frenchman Formation is different from the layer above it, called the Ravenscrag Formation, because they are separated by a special boundary from a very old time called the Cretaceous-Paleogene boundary. Scientists now know they are two separate layers.

The Frenchman Formation sits on top of other rock layers after a break called an erosional unconformity. Depending on how much erosion happened, it can rest on the Whitemud Formation, the Battle Formation, the Eastend Formation, or the Bearpaw Formation. It is about the same age as parts of the Scollard Formation, the Willow Creek Formation, the Coalspur Formation in Alberta, and the Hell Creek Formation in Montana and North Dakota.

Paleontology

Scientists have found interesting fossils in the Frenchman Formation. J.E. Storer studied fossils of ancient mammals from a place called Gryde locality. These included species named Parectypodus and Alphadon. They also found a bone from a bird, possibly from a type called Cimolopteryx, at the same spot.

Researchers also collected plant fossils from Grasslands National Park and Chambery Coulee. These plants showed signs that the area had frequent forest fires. After a fire, shrubs would grow first, and later, forests of coniferous and hardwood trees would return. By studying these leaves, scientists estimated that the area had warm temperatures, around 12–14 °C (54–57 °F), and was covered in a deciduous mixed forest in a temperate climate.

Dinosaurs reported from the Frenchman Formation
Genus	Species	Location	Material	Images
Ankylosaurus	A. magniventris
cf. Anzu	cf. A. sp.		Two manual unguals
?Dromaeosaurus	?D. sp.	Scotty site	Three teeth
Edmontosaurus	E. annectens		"Complete skull, [three or four] partial skulls."
	E. saskatchewanensis
Leptorhynchos	L. sp.		A partial skeleton
Ornithomimus	Ornithomimus sp.
Sphaerotholus	cf. S. buchholtzae		"nearly complete left postorbital"
Thescelosaurus	T. assiniboiensis		Nearly complete skeleton
Torosaurus	T. sp.		Frill
Triceratops	T. prorsus	Redpath, Saskatchewan	Nearly Complete Skull, one other partial skull
Tyrannosaurus	T. rex		Nearly complete skeleton