A radiocarbon-dated gravel deposit in Calgary, Alberta, has yielded a large humerus referred to the extinct camelid, Camelops cf. hesternus. With a date of 11 300 ± 290 BP (RL-757) this is the first securely dated postglacial record of Camelops in Canada. Studies of the gravels show them to represent a period of rapid aggradation by a braided river, subsequent to the drainage of glacial Lake Calgary. The gravels are equivalent in age and characteristics to the Bighill Creek Formation of the Cochrane area, 30 km west of Calgary; and are therefore assigned to that formation. Later fill units are, however, excluded from the formation as they represent Holocene cut-and-fill events of differing hydrologic significance. Recent suggestions that Lake Calgary persisted until 9000 years BP can now be rejected on the basis of stratigraphy and radiocarbon dates. Studies of the camel humerus suggest some revisions in our views concerning morphologic variation in the species: the species was probably more plastic than has been accepted to date. Associated Bison bison antiquus and Equus conversidens from the same gravels (Gallelli and Galvin Pits) are briefly described. The ungulate fauna from these pits suggests a semiforest habitat with extensive shrub and grassland elements.

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