formation

A pair of Wendiceratops running through the Oldman formation.

Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

Brachylophosaurus canadensis TMP 1990.104.0001, Oldman Formation, Milk River, Alberta. Original, not cast. At the Royal Tyrrell Museum of Palaeontology.

Campanian fauna from the Oldman Formation: Wendiceratops, Corythosaurus, Scolosaurus, Chasmosaurus and "Troodon"

Geographic and stratigraphic relationships of the holotype EMK 0012 and the Loki Quarry in northern Montana. (A) Regional relationships between the cross-border paleontological sites in the Oldman and Judith River formations along the Milk River and in Kennedy Coulee in Alberta and Montana. (B) Generalized stratigraphic section in the Kennedy Coulee area modified after Goodwin & Deino (1989) and Rogers, Eberth & Ramezani (2023) with the relationships between the Foremost and Oldman formations in Canada and the Judith River Formation in Montana. Relative placements of important taxa in this area are indicated. Position of 40Ar/39Ar dates originally obtained by Goodwin & Deino (1989) are shown in relation to the new U–Pb CA-ID-TIMS date for KC061517-1 by Ramezani et al. (2022). Bentonite ash beds are only 5 to 7 cm thick so they are exaggerated for clarity. Scale bars delineated in map view are indicated kilometers and in meters stratigraphically.

Brachylophosaurus, Daspletosaurus and Scolosaurus from the Oldman Formation.

Brachylophosaurus canadensis skull (original). From the Oldman Formation, Milk River, Alberta. On display at the Royal Tyrrell Museum, Alberta, Canada.

Brachylophosaurus canadensis (TMP 2005.000.0029), Royal Tyrrell Museum, Drumheller, Alberta, 2025-07-13; cast, Campanian, from the Oldman Formation

Sandstones of the Milk River Formation flank the Milk river at Writing-on-Stone Provincial Park, Alberta.

African locality: 5, Majunga, Maevarano Formation (Campanian): Rahonavis ostromi.

Bryce Canyon geologic map, showing a variety of rock formations in the national park including the Claron Formation, which forms the park’s famous red hoodoos.

Locality map: Grand Staircase-Escalante National Monument, southern Utah. Map showing locality (indicated by star) of Nasutoceratops titusi holotype UMNH VP 16800, recovered from the Kaiparowits Formation of Grand Staircase-Escalante National Monument (GSENM). GSENM is bounded by the red rectangle and silhouetted in dark gray on the inset of Utah and surrounding states (modified from [1]). The original map has been modified to show Nasutoceratops instead of Machairoceratops as in the original source. New location based on map in Ceratopsid Dinosaurs from the Grand Staircase of Southern Utah, page 489.

Locality map: Grand Staircase-Escalante National Monument, southern Utah. Map showing locality (indicated by star) of Kosmoceratops richardsoni holotype UMNH VP 17000 and assigned subadult UMNH VP 16878, recovered from the Kaiparowits Formation of Grand Staircase-Escalante National Monument (GSENM). GSENM is bounded by the red rectangle and silhouetted in dark gray on the inset of Utah and surrounding states (modified from [1]). The original map has been modified to show Kosmoceratops instead of Machairoceratops as in the original source. New location based on map in Ceratopsid Dinosaurs from the Grand Staircase of Southern Utah, page 489.

Kaiparowits Formation (Campanian; Upper Cretaceous) at The Blues, near Powell Point (peak to the left) composed of the Claron Formation.

Natural-colour satellite image of part of the Kaiparowits Basin (a central portion of Grand Staircase-Escalante). The branch-like shapes are networks of canyons carved by rivers that dried up millions of years ago. The ridge running roughly north-south through the scene is the Cockscomb, which is surrounded by distinct rock formations deposited at different times in the geologic past. West of the Cockscomb is the Navajo Sandstone, dating from the Triassic. East of the Cockscomb are two formations from the Cretaceous: the light-toned Wahweap and darker Kaiparowits.

Map of Grand Staircase-Escalante National Monument (GSENM), southern Utah (A), and generalized stratigraphic section of the upper Campanian Kaiprowits Formation (B). The approximate stratigraphic position of Akainacephalus johnsoni is located near the base of the middle unit within the Kaiparowits Formation. The map highlights the GSENM boundary (dashed line), showing the geological distribution and outcrops of the Cretaceous Kaiparowits, Wahweap, and Straight Cliffs formations. The red star indicates the Horse Mountain area, from which Akainacephalus johnsoni was recorded. Map and stratigraphic column modified from Roberts (2005). Radioisotopic dates used from Roberts, Deino & Chan (2005) and Roberts et al. (2013), respectively.