Horseshoe Canyon Formation

The Horseshoe Canyon Formation is a special layer of rock found in southwestern Alberta. It gets its name from Horseshoe Canyon, an area of unusual land shapes called badlands near the town of Drumheller. This rock layer is part of a bigger group called the Edmonton Group.

In the Red Deer River Valley near Drumheller, the Horseshoe Canyon Formation is about 250 metres thick, but it gets thicker as you move west toward Calgary. It formed during the Late Cretaceous period, mostly during the Campanian to early Maastrichtian stages. The rocks are made of different types of mud, sand, and coal, showing that long ago, the area had floodplains, river channels, and swampy forests. These places helped preserve many fossils.

Many important fossils have been found here, including several kinds of dinosaurs like Albertosaurus, Edmontosaurus, and Saurolophus. Scientists have also uncovered fossils of mammals, reptiles, amphibians, fish, and plants. This formation gives us valuable clues about life and the environment from millions of years ago. Today, the area around Drumheller is famous for its beautiful rock formations and important fossil discoveries.

Oil/gas production

The Drumheller Coal Zone is an important area for finding natural gas trapped in coal. Between the towns of Bashaw and Rockyford, this coal zone is not very deep—only about 300 metres below the surface—and is quite thick, ranging from 70 to 120 metres. It contains layers of coal mixed with sandstone and shale, making it a good spot for drilling. Experts believe there is a huge amount of gas stored in the coal across Alberta, estimated to be around 14 trillion cubic metres.

Biostratigraphy

The timeline shown here is based on research done by David A. Eberth and Sandra L. Kamo in 2019.

Dinosaurs

Ornithischians

Ankylosaurs

Hadrosaurs

Marginocephalians

Ceratopsians

Pachycephalosaurs

Thescelosaurs

Theropods

Maniraptorans

Ornithomimids

Tyrannosaurs

Ankylosaurs reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Anodontosaurus	A. lambei	Horsethief, Morrin, and lowest Tolman	[Five] skulls, mandibles, cervical vertebra, caudal vertebrae, dorsal vertebrae, sacrocaudal vertebrae, sacrum, illium, ischium, partial pelvis, coossified ribs, femur, ?manual phalanx, tail clubs, numerous cervical half-rings and osteoderms.
Edmontonia	E. longiceps	Upper Horsethief	A skull with mandible, dorsal vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, cervical ribs, dorsal ribs, humerus, radius, ulna, radius, ilia, ischia, both pubes (?), femur, tibia, fibula and osteoderms.
Euoplocephalus	E. tutus

Hadrosaurs reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Edmontosaurus	E. regalis	Horsethief; likely present in Drumheller.
Hypacrosaurus	H. altispinus	Morrin and Tolman.	"[Five to ten] articulated skulls, some associated with postcrania, isolated skull elements, isolated postcranial elements, many individuals, embryo to adult."
Saurolophus	S. osborni	Upper Morrin and Tolman.	"Complete skull and skeleton, [two] complete skulls."

Ceratopsians reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Anchiceratops	A. ornatus	Horsethief, Morrin, and Tolman; may have been present in Drumheller	[Two] nearly complete skulls and [seven] partial skulls.
Arrhinoceratops	A. brachyops	Horsethief	A nearly complete skull.
Eotriceratops	E. xerinsularis	Carbon	Premaxillae, maxillae, rostral, supraorbital horncore with lacrimal, prefrontal, frontal, postorbital, jugal, epijugal, quadratojugal, quadrate, partial parietal, squamosal frill, braincase, syncervical, cervical vertebrae, dorsal vertebrae, ribs and fragments of ossified ligaments.
Montanoceratops	M. cerorhynchus	Upper Tolman	An isolated braincase.
Pachyrhinosaurus	P. canadensis	Drumheller and Horsethief	[Two] partial skulls.

Pachycephalosaurids reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Sphaerotholus	S. edmontonense	Tolman	A frontoparietal.

Thescelosaurids reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Parksosaurus	P. warreni	Tolman	A partially articulated skeleton and partial skull.

Maniraptors reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Albertavenator	A. curriei	Horsethief	[Two] frontals.
Albertonykus	A. borealis	Upper Tolman	Ulna, tibiae, metatarsals, manual ungual, pedal phalanxes and unidentified pedal phalanges.
Apatoraptor	A. pennatus	Horsethief	A palatine, mandibles, ceratobranchials, axis, cervical vertebrae, dorsal vertebrae, pectoral girdles, sternal plate, forelimb, ilium, femur, tibia and fibula.
Atrociraptor	A. marshalli	Lower Horsethief	Premaxillae, maxilla, dentaries, teeth and numerous bone fragments.
Epichirostenotes	E. curriei	Horsethief, Morrin, and Tolman	A maxilla, probable palatine, partial braincase, cervical vertebrae, dorsal vertebrae, caudal vertebrae, synsacrum, an anterior and a posterior cervical rib, a mid-dorsal rib, fragments of ilia, ischium, both pubes, partial tibia, and unidentifiable bones.

Ornithomimids reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Dromiceiomimus	D. brevitertius		Several specimens. type specimen
Ornithomimus	O. currelli
	O. edmontonicus	Drumheller, Horsethief, Morrin, and Tolman	Several specimens, type specimen
Struthiomimus	S. altus	Drumheller, Horsethief, and Morrin

Tyrannosaurids reported from the Horseshoe Canyon Formation
Genus	Species	Stratigraphic position	Material	Images
Albertosaurus	A. arctunguis
	A. sarcophagus	Horsethief, Morrin, and Tolman; likely present in Drumheller and Carbon.	Several skeletons and partial skeletons, type specimen
Daspletosaurus	D. sp.

Other animals

Mammals

Other reptiles

Fish

Mammals reported from the Horseshoe Canyon Formation
Genus	Species	Images
Didelphodon	D. coyi

Reptiles reported from the Horseshoe Canyon Formation
Genus	Species	Material	Images
Stangerochampsa	S. mccabei	"a skull, partial lower jaws, and partial postcranial skeleton"
Champsosaurus	C. albertensis	"partial skeleton with partial skull"
Leurospondylus	L. ultimus	"a partial skeleton"
Basilemys	B. morrinensis	"nearly complete shell"