The raging floodwaters of the Missouri River have exposed a cache of dozens of bison skulls, including specimens as much as 10,000 years old, downstream from Oahe Dam.
The skull collection is likely headed for display in Rapid City museums.
Employees of the U.S. Army Corps of Engineers discovered the skulls in recent weeks as the Missouri River has receded following this summer's flooding. The skulls were found on a sandbar near Pierre, but the Corps declined to reveal the exact location of the cache to deter looters.
Corps employees removed the skulls and are transferring them to the state Archeological Research Center in Rapid City.
Archeologists there and at the South Dakota School of Mines & Technology will travel to the location of the find to search for more bones and fossils.
"We're going to go out to the area where they were collected and see if we can identify other species that are relatively uncommon - specifically Ice Age mammals, like ground sloth, camel (and) horse," said assistant state archaeologist Michael Fosha.
It is unclear how all the skulls ended up in one spot. Among the possibilities are that that location was a natural gathering place for buffalo or the site of a village or hunting grounds. It is also possible, Fosha said, that the skulls came from various locations and simply washed up to the same place.
Fosha said there is a history of the Missouri turning up the buffalo bodies.
"When the earliest fur traders would go upriver in the Missouri in their canoes, they would virtually be dodging bison (remains) sometimes, floating downstream," he said. "By the late 1840s, you didn't see them any more."
Though he hasn't had a chance to study the skulls in detail, just from their appearance Fosha said he could identify several species. Some skulls appear to be relatively modern, while others bear the wider horns that signify a bison species that lived thousands of years ago.
The skulls will probably end up divided between the Archaeological Research Center and the School of Mines - to be displayed in museums in both places.
People outside of Rapid City might also get a chance to see the skulls.
"We might put together a traveling exhibit of bison through time so the public can see this and understand what we as archaeologists already know," Fosha said.
So far this is the only archaeological site the Corps is aware of being revealed by this year's Missouri River floods. But if any others are uncovered, Corps spokeswoman Maggie Oldham said it is illegal for citizens to take the finds for themselves.
"These are of cultural significance... and it's unlawful to remove these items from public lands," Oldham said. "If the public finds or notices items like this, be sure to notify proper authorities, the local Corps office, so we can remove the items and make sure they're protected."
Contact David Montgomery at 394-8329 or firstname.lastname@example.org