Two miles northeast of here, the Cooper Paleoindian bison kill was the scene of the largest known Folsom bison kills about 10,500 years ago. In each event, more than 30 bison were herded into a dead-end gully, where hunters on the rim killed them with spears tipped with finely crafted Folsom points. A bison skull beneath the second kill was painted with red zigzag lines using red hematite to ensure a successful hunt. It is the oldest painted skull in North America and the earliest evidence of hunting ritual for the Plains region.