My wife, Nancy, and I have a 75-acre horse farm in Ledyard, Connecticut, that we built four years ago and named Standing Stones after a 12-foot-high boulder, a glacial erratic left after the retreat of the ice sheet 20,000 years ago. The stone bordered an old logging trail, which was the only way on to the land when we first visited it in 2005. But we didn’t really know anything about the stones until one spring morning when a man called Bill Saums came to see me.Saums had emailed me a few weeks earlier to say that he knew the land on which our farm was built and that he would like to talk to me about some interesting Native American structures that he had found on our property. He was in his 40s, with a wise, open face, curly black hair, and a purposeful demeanor. No sooner had we shaken hands than he was off, walking out of the barn with me in tow. “I have some things to show you. I think you will be surprised.” I learned that Bill has walked the countryside, often with members of the New England Antiquities Research Association, seeking evidence of earlier cultures. In this way, and through extensive …