Late Pleistocene protein residues from the Mahaffy cache, Colorado

This paper reports the analysis of protein residues from tools recovered in a cache within the city limits of Boulder, Colorado, USA. This cache included a total of 83 artifacts, all of which we subjected to cross-over immunoelectrophoresis (CIEP). Four of the 83 produced results, with residues from each of these reacting with antigens from a different taxon: one tool shows evidence of use on sheep, one on bear, one on horse, and one on camel. Varieties of sheep and bear have been present in Colorado throughout human history, but horses and camelids have been in the state either during the Pleistocene or the last 200 years. Several lines of evidence indicate that the cache cannot be recent, and our CIEP results therefore imply that the cache date to the late Pleistocene. Typological aspects of the artifacts in the cache are consistent with artifacts known to be Clovis, and the combination of CIEP and typological data thus indicate that the cache is Clovis as well. These data contribute to an increasing dataset documenting the broad range of animals other than elephants hunted by Clovis groups in North America.

► We present the results of protein residue (CIEP) analysis on stone tools from a cache found in Boulder, Colorado.
► The cache includes 83 artifacts imported from west of the Continental Divide.
► Four of these tools bear traces of animal protein, including sheep, bear, horse, and camel.
► Horse and camel indicate that the cache was deposited during the Late Pleistocene.
► Late Pleistocene/Clovis groups exploited a wider range of animals than is often asserted.