Frenchman Formation

The Frenchman Formation is a special layer of rock from a very long time ago, during the Late Cretaceous period, near the end of the time when dinosaurs lived. You can find this rock layer in southern Saskatchewan and the Cypress Hills area in southeastern Alberta. A scientist named G.M. Furnival described this formation in 1942 after looking at rocks along the Frenchman River, between places called Ravenscrag and near Highway 37.

This rock layer is important because it holds fossils from some of the last dinosaurs that ever lived. It is very similar to another famous rock layer called the Hell Creek Formation in the United States. Both places help scientists learn about the world right before the dinosaurs disappeared from Earth.

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 rounded quartzite pebbles, especially above the base in some places.

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 time called the Maastrichtian, which was the last part of the Cretaceous period. The top of this formation marks the point where the Cretaceous period ended and a new time began, known as the Paleogene period. This change is shown by studying tiny fossils and finding a special layer of soil that contains a rare element called iridium.

Relationship to other units

The Frenchman Formation is a layer of rock from a long time ago, and scientists now know it is different from the layer above it called the Ravenscrag Formation. Even though some people thought they were the same, they are separated by a special line in the Earth called the Cretaceous-Paleogene boundary.

The Frenchman Formation sits on top of other rock layers, but there is a break called an unconformity between them. Depending on how much erosion happened, the Frenchman Formation can rest on different layers such as the Whitemud Formation, Battle Formation, Eastend Formation, or Bearpaw Formation. It is about the same age as some layers in Alberta and formations in Montana and North Dakota.

Main articles: Ravenscrag Formation, Cretaceous-Paleogene boundary, unconformity, Whitemud Formation, Battle Formation, Eastend Formation, Bearpaw Formation, Scollard Formation, Willow Creek Formation, Coalspur Formation, Hell Creek Formation, Montana, North Dakota

Paleontology

Scientists have found fossils in the Frenchman Formation that help us learn about life from long ago. They discovered remains of small mammals, like Parectypodus and Alphadon, at a place called the Gryde locality. They also found a piece of bone from a bird called Cimolopteryx.

Plants found in areas like Grasslands National Park show what the forests looked like back then. These plants suggest that forests sometimes caught fire, and after a fire, new shrubs would grow before the forests returned to their usual mix of trees. Studies of the leaves indicate that the area had warm temperatures, around 12–14 °C (54–57 °F), with forests made of many different kinds of trees.

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