Eight thousand years ago, Minnesota looked like another world.

Prairie grasses covered the land, with trees sparse except in the extreme northeast. The landscape was extremely dry, with lakes reduced to waterholes and rivers withered to streams. Small groups of native people roamed the wild, hunting bison that were 50 percent larger than the species we know today. They camped in the river bottoms, close to water, fish and game.

Now archaeologists are getting a priceless peek at that ancient past, known as the Archaic Period, because of a rare campsite discovered along the Minnesota River in Chanhassen during a routine survey in preparation for bridge work.

“Basically, it’s like a time capsule — a very well-preserved record left pretty much intact of where it was deposited,” said archaeologist Frank Florin, principal investigator at the site, whose precise location officials are not revealing to keep away vandals and treasure hunters. “It’s exciting to know that you’re looking at things as they were 8,000 years ago, essentially.”

Florin found the site near the junction of Hwy. 101 and County Road 61, also known as Flying Cloud Drive.

Starting next year, the area will be excavated as part of a $54 million replacement of the Hwy. 101 bridge linking Carver County and Shakopee. Federal rules require an archaeological survey when such a project is underway to determine if anything of historic value would be disturbed.

Spear point tip and grater found at archaeological site at construction site on the Minnesota River.

The artifacts were buried 10 to 12 feet below the ground in an area mostly covered by peat, cattails and swamp.

Campsites in the river valley were occupied in a drier period of history, said Minnesota state archaeologist Scott Anfinson, probably by small groups of no more than 20 people. Over the centuries, the climate became wetter, river bluffs eroded and the campsites were covered with silt and soil and filled in as wetlands.

That’s why ancient sites are so rare, he said.

“Wet environments are very difficult to find, and very difficult to dig, but they’re very rewarding because of what you can get out of them,” Anfinson said.

The depth and lack of oxygen preserves not only stones and tools, but also organic material such as plants that can be analyzed and dated.

“We can actually say, ‘This spearhead was made by these people who lived at exactly this time,’ so we can get a huge amount of information,” he said.

Florin said some of the stones used as tools appear to have come from North Dakota or western Wisconsin, suggesting that the native people traveled some distance in their hunting or that they interacted and traded with other groups.

Craig Johnson, archaeologist for the Minnesota Department of Transportation, said part of the ancient campsite will be destroyed to install deep footings for new bridge piers next year, so a fall excavation is planned to retrieve additional artifacts that otherwise would be lost.

“We don’t have more than about a half a dozen of these archaeological sites from this period that are known in the Minnesota River Valley, so this is pretty significant,” he said.

Painstaking work

In the initial survey work that found evidence of the encampment, Florin and a crew used soil core augers — similar to post-hole diggers with extensions — to remove samples of dirt, clay and mud and to screen them for artifacts. The team hand-drilled about 600 holes in the fall of 2012 and this spring.

They found artifacts in several spots along a 400-yard stretch that includes both public right of way and private land. There is at least one buried campsite, Florin said, and perhaps remnants of others.

Florin, a private archaeologist and owner of Florin Cultural Resource Services LLC, was hired by Carver County to do the initial survey. His final report is nearing conclusion. The budget for field work and analysis was about $100,000.

The native people buried their dead high on the river bluffs, but camped on the banks.

“We found evidence for making stone tools, butchering and processing animals, and we found one fire hearth,” Florin said. The crew also unearthed spear-point fragments, hide-scraping tools, and animal remains that included turtles, fish and bison.

“Since we know so little about this time period, even small campsites are very important for what they tell us about people’s diet, what their tools were and how they lived,” Florin said.

A bigger dig lies ahead

Carver County road officials are now working with the archaeologists to determine the location, scope and budget for this fall’s larger excavation.

Florin said that because of the expense of draining part of a wetland, the area to be dug will need to be relatively modest in size — perhaps about 300 square feet in total.

The excavation will essentially be a rescue operation to retrieve materials from what seems to be the area’s richest concentration of artifacts, Johnson said. The findings will be numbered, cataloged, photographed and analyzed with a written report, he said, and probably archived at the Minnesota Historical Society.

As part of the archaeological work, Florin said he has communicated with the nearest Indian tribe, the Shakopee Mdewakanton Sioux Community.

A spokeswoman for the tribe said it “did not feel comfortable addressing the artifacts, because they could go back as far as 8,000 years and could potentially be associated with a number of tribal communities.”

Florin said there’s no possibility that the area was a cemetery — a designation that would have triggered a dramatically different response by both archaeologists and developers, as well as far more input from contemporary tribes. “We were digging on campsites, not mounds, and we found animal bones, not human bones,” Florin said.

The discovery is a reminder that native people have lived in Minnesota at least since the glaciers retreated 10,000 to 12,000 years ago, Florin said.

“There were prior occupants, and part of what archaeology does is bring that information and knowledge to the present day,” he said.