The site offered a rare window into life in Minnesota 8,000 years ago.
Janet Peterson, 75, her husband LeRoy Peterson, 85, and their dog Bailey, 10, maintain an archaeological site in their backyard in Granite Falls, Minn. (Jp Lawrence)
An ancient bison skull.
Visitors can see bison skulls from the Peterson site at the Yellow Medicine County Museum & Historical Society in Granite Falls, Minn. (Jp Lawrence)
LeRoy Peterson holds a wild flower in his pasture.
LeRoy Peterson holds a wild flower in the pasture near where he found bison bones and early human artifacts in 1988. (Jp Lawrence)
Artifacts from the Peterson site can be seen in a display at the Yellow Medicine County Museum & Historical Society