Age

The K-Pg boundary in the Scollard Formation. The coals are earliest Paleocene in age, lighter shales below are Maastrichtian. The lighter rock at the very base of the dark coals represents the K-Pg boundary.

The K-Pg boundary occurs at the base of the lowermost seam of Ardley coal zone, based on dinosaurian and microfloral evidence,^[5] as well as the presence of the terminal Cretaceous iridium anomaly.^[6] The upper member is therefore of early Danian age, while the lower member is of latest Maastrichtian age.

Distribution

The Scollard Formation is present in the subsurface throughout much of southwestern Alberta,^[7] and it outcrops extensively along the banks of the Red Deer River in the area of Trochu.^[8] Both the upper and lower members thin from west to east. Thicknesses for each member range from more than 300 metres (980 ft) near the foothills of the Canadian Rockies to less than 100 metres (330 ft) near the outcrops in south-central Alberta.^[1]

Relationship to other units

The Scollard Formation rests disconformably on the Late Cretaceous Battle Formation in the southwestern Alberta plains, on the Wapiti Formation in the northwestern plains, and on the Brazeau Formation in the foothills. It is unconformably overlain by the Paskapoo Formation, and where the Paskapoo has been removed by erosion, the Scollard is exposed at surface or covered by Quaternary sediments.

The Scollard grades into the Willow Creek Formation in the southern Alberta plains and the Coalspur Formation in the Alberta foothills. The Ardley coal zone in the upper portion is equivalent to the lower part of the Coalspur coal zone of the Coalspur Formation,^[9] and is correlated with the lower part of the Ravenscrag Formation of southern Saskatchewan, which is also coal bearing.^[10] The Late Cretaceous member is equivalent in age to the Frenchman Formation of Saskatchewan, the Hell Creek Formation of Montana, and the Lance Formation of Wyoming .^[1]

Flora

Plant fossils from the upper, early Paleocene member of the Scollard Formation include species of the ferns Botrychium, Woodwardia and Azolla; the conifers Metasequoia and Glyptostrobus; the monocot Limnobiophyllum (a relative of duckweeds); and the dicots Cercidiphyllum and Platanus.^[12][13]

Vertebrates

Crocodylian Albertosuchus, acanthomorph fish Lindoeichthys and unnamed esocid fish are known.^[14][15][16]

Theropods

Ornithomimus remains have been unearthed here.^[17] Two caenagnathid taxa, a large-bodied one similar to Caenagnathus and a small-bodied one similar to Leptorhynchos have been found.^[18]

Theropods
Genus	Species	Location	Stratigraphic position	Material	Description	Images
cf. Dromaeosaurus[19]	Indeterminate[19]			Teeth	A dromaeosaurid	Dromaeosaurus Saurornitholestes Troodon Tyrannosaurus
cf. Paronychodon[20]	Indeterminate[19]
cf. Richardoestesia[21]	cf. R. gilmorei[22]
	cf. R. isosceles[23]
cf. Saurornitholestes[19]	cf. S. langstoni[19]
Troodon[24]	Indeterminate[19]			A Single Tooth
Tyrannosaurus[19]	T. rex[19]			Partial Skeleton

Ornithischians

Torosaurus remains have also been unearthed in this region.^[25] Edmontonia remains have also been unearthed here and in the nearby areas.^[17]

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Ornithischians
Genus	Species	Location	Stratigraphic position	Material	Description	Images
Ankylosaurus[19]	A magniventris[19]			Complete skull, both mandibles, ribs, caudal vertebrae, tail club, both humeri, left ischium, left femur, right fibula, and osteoderms.	An ankylosaurine ankylosaurid also found in the Lance, Frenchman, Ferris and Hell Creek Formations.	Ankylosaurus Edmontosaurus Leptoceratops Pachycephalosaurus Thescelosaurus Triceratops
Edmontosaurus[19]	E. annectens[19]
Leptoceratops[19]	L. gracilis[19]			Partial Skull
cf. Pachycephalosaurus[19]	P. wyomingensis[19]			Domed Parietal
Thescelosaurus[19]	T. edmontonensis[19]			Complete Skeleton	Referred to Thescelosaurus sp.[26]
Triceratops[19]	indeterminate[19]			Skull

Bibliography

• Ryan, M. J., and Russell, A. P., 2001. Dinosaurs of Alberta (exclusive of Aves): In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 279–297.
• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.