Context, Provenance and Technology of a Western Stemmed Tradition Artifact Cache from the Cooper’s Ferry Site, Idaho

The discovery of an artifact cache containing Western Stemmed Tradition (WST) projectile points in a clearly defined pit feature at the Cooper’s Ferry site offers a unique perspective on early lithic technology and logistical organization in western North America. A description and analysis of the cache feature reveals several new insights, including: a rocky cairn capped the surface of the pit feature; some of the artifacts were made from cryptocrystalline silicates found 16 km away; debitage analysis, including aggregate and attribute based measures, identified two distinct lithic reduction stages present in the cache; new radiocarbon assays suggest that the cache is probably not early Holocene in age and may date to associated age estimates of 11,410–11,370 radiocarbon years before present (B.P.). Unlike Clovis caches, the Pit Feature A2 cache at Cooper’s Ferry appears to be a generalized toolkit that was probably placed at the site for future use. If the 11,410–11,370 radiocarbon years B.P. assays date the creation of the Pit Feature A2 cache, then its creators were probably not pioneers in the lower Salmon River canyon but possessed local knowledge about the landscape and raw material sources; these patterns suggest greater time depth for WST foragers.