Refining chronology for surface collections: A new adaptation of morphological dichotomous keys for the Plains Typology and the Greater Yellowstone Ecosystem

This paper uses new lithic research with well-dated stratified collections from the foothills of the Absaroka Mountains and adjacent Bighorn Basin to build a dichotomous key for chronologically classifying points in the northern Greater Yellowstone Ecosystem (GYE) as Late Prehistoric (200–1,500 cal BP), Late Archaic (1,500–3,200 cal BP), Middle Archaic (3,200–5,700 cal BP), Early Archaic (5,700–8,500 cal BP) or Paleoindian (8,500–12,000 cal BP). The Plains Typology, which is currently used throughout the GYE, has never been formally based on points with affiliated absolute dates. Further, it has always been unclear how well this typology functions in the mountains of the GYE. Based on detailed attributes from over 600 points, including Mummy Cave (48PA201), a foundational chronology for the region, we build a key intended for use with fragmentary surface collections. We then use this key to consider variation in high elevation projectile points from the Beartooth and Absaroka Mountains.