Archaeologists are racing earthmovers (South Dakota)

Jim Donohue is trying to solve a mystery that has been building for about 12,000 years, but he has only a few days left to gather clues. Donohue, senior archaeologist with the state Archaeological Research Center in Rapid City, is supervising the excavation of a site occupied by generations of ancient hunters off S.D. Highway 79 near Buffalo Gap.

He and his crew have found artifacts, bison bones and two ancient spear points, including a rare Folsom spear point found in late May.

The new Heartland Expressway will be built over the site where ancient hunters made spear points, and other people, probably women, processed meat, scraped hides and boiled the marrow out of bones from now-extinct giant bison and other animals.

The ancient site was found while preparing for construction of the new highway, and nine 1-square-meter holes were excavated in 2003. Archaeologists found a Goshen spear point estimated to be 12,000 to 13,000 years old or older, as well as many tools, bones and charcoal from old campfires.