While on a trip to New England, I asked my mother what the difference was between a stone and a rock.
“A rock is natural,” she said. “A stone’s been worked on.”
“So why is it Plymouth Rock instead of Plymouth Stone?” I asked.
“Because Plymouth Rock wasn’t really worked on,” she said. “Although, they did break it apart and moved it around a few times. And souvenir-seekers have been breaking off pieces of it for years. Oh, and they carved the year into it. So, technically, it should be Plymouth Stone.”
I think historians have rocks in their heads.