A group of non-scientists might have found the proof.
The group, made up mostly of Native American tribal citizens, utilized a remote-operated underwater vehicle in the Straits of Mackinac to take a look at Enbridge’s Line 5 oil and natural gas pipelines on the lake bottom. But among the things they found were stones they say appear arranged in circular and linear patterns on the lake floor.
If that was done by the hands of humans, it occurred when the Straits area, which divides Michigan’s peninsulas, was last above water — near the end of the last Ice Age, about 10,000 years ago.
For more, check out this USA Today story.