GSC 27054, Mahon Creek [Dunvegan Fm] (Cretaceous of Canada)

Where: Alberta, Canada (53.8° N, 118.7° W: paleocoordinates 56.0° N, 73.1° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Dunvegan Formation, Cenomanian (100.5 - 93.9 Ma)

• STRATIGRAPHIC RELATIONS: The Dunvegan Formation is overlain conformably by the Kaskapau Formation in the Peace River area, except for an apparent hiatus near Watino, Alberta where the Dunveganoceras Zone seems to be missing. The contact is usually transitional, and where the basal unit of the Kaskapau becomes overly sandy the term Sakunka Member of the Dumvegan was suggested by Spieker (1921) for such beds in the Pine River area of British Columbia. The Dunvegan is underlain conformably and transitionally by shales of the Fort St. John Group, which are referred to as Sully and Cruiser formations in northeastern British Columbia and as the Shaftesbury Formation in the Peace River plains of Alberta. The Dunvegan grades laterally to the east into the marine Labiche Formation and to the south into the middle part of the Sunkay Member of the Blackstone Formation. AGE: Cenomanian, on the basis of ammonoid and bivalve biostratigraphy. STRATIGRAPHIC POSITION: From unit 3 within local section.

• bed-level stratigraphic resolution

Environment/lithology: marine; poorly lithified, brown, gray, yellow sandstone

• ENVIRONMENT: Siliciclastic marine.
• SPECIFIC LITHOLOGY: Marine, nonmarine and deltaic sandstone, light grey to yellowish buff. LITHIFICATION: Poorly lithified on the basis of specimens figured elsewhere.

Size class: macrofossils

Reposited in the GSC

Collection methods: surface (in situ),

• COLLECTOR: Stott, c. 1960's. REPOSITORY: Geological Survey of Canada.

Primary reference: D. F. Stott. 1963. The Cretaceous Alberta Group and equivalent rocks, Rocky Mountain foothills, Alberta. Geological Survey of Canada Memoir 317:1-306 [A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 89191: authorized by Austin Hendy, entered by Austin Hendy on 08.05.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for marine invertebrates. NOMENCLATURE: An authoritative publication, and with relatively antiquated nomenclature but species-resolution identifications.
Bivalvia
 Ostreida - Ostreidae
Ostrea sp. Linnaeus 1758 oyster
 Pectinida - Anomiidae
 Pholadida - Corbulidae
 Unionida - Unionidae
Pleurobema dowlingi freshwater mussel
Gastropoda
 Cerithioidea - Thiaridae
"? Melania sp." = Thiara
"? Melania sp." = Thiara Röding 1798 snail