I hadn't seen this episode since I was a kid, and I thought it would be of some interest here. It's the TV show In Search Of narrated by Leonard Nimoy. The episode is called Strange Visitors and it first aired on April 24, 1977. It's about Mystery Hill (America's Stonehenge) in Salem, NH.
It's a good study in what the scientific community believed about Indians -- and stone structures in New England -- just three short decades ago.
The episode is posted on YouTube in three parts. Just the first part is embedded below. Follow the links to see all three parts. (Warning! Barry Fell alert.)