At the Painted Coulee site (24JT86), pictographs depicting both atlatl and bow technology are present. We utilized plasma oxidation followed by accelerator mass spectrometry to directly radiocarbon date the organic material in two paint samples. A red painting of an anthropomorph with a shield and a possible atlatl in conflict with a fleeing person holding a bow was dated to 1790 ± 50 RCYBP (cal AD 120–390). Another red anthropomorph wearing snowshoes and holding a bow was dated to 1710 ± 45 RCYBP (cal AD 240–425). Radiocarbon dates for underlying oxalate minerals provided maximum ages for the paintings that are consistent with the direct ages. This early example of Plains Biographic rock art is significant because it illustrates a scene between a Late Archaic shield-bearing warrior with a possible atlatl and an anthropomorph with a bow and arrow at a time when bows first came into use on the Northwestern Plains.
