Frenchman Formation

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

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

Lithology

The Frenchman Formation is made of olive-green to brown sandstone with layers of claystone. It also has small parts of conglomerate with quartzite pebbles.

Thickness and distribution

The Frenchman Formation is located 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 end of the Maastrichtian age. This age was part of the Late Cretaceous period. The top of this formation marks the Cretaceous-Paleogene boundary. This boundary shows changes in tiny fossils. In some places, it includes a layer with a special element called an iridium anomaly. This helps scientists learn about important events in 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.

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 collected plant fossils from Grasslands National Park and Chambery Coulee. These plants showed that the area had frequent forest fires. After a fire, shrubs would grow first, and later, forests would return. By studying these leaves, scientists learned 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