Artifacts from more than 20 late prehistoric components in the Mackenzie valley are described and compared with those from contemporaneous assemblages from neighbouring areas. MacNeish's Spence River phase is expanded to cover this material, which seems to exhibit at least some integrity and distinctiveness, and which appears to date from about A.D. 700 to the time of European contact. Certain technological similarities are noted with the Klo-Kut and Aishihik phases to the West and the late Taltheilei tradition to the East, but these similarities are difficult to synthesize into any meaningful outline of Canadian Athapaskan prehistory.