Interesting features found by Nick Holland adjacent to a rock pile site in Hopkinton State Park.
...I also found a 10 to 15 foot diameter hemispheric pit in the woods, much like one I'd found in Sandwich last year. Just as I was leaving, I stumbled across another hemispheric pit, with a short, low wall connecting it to a boulder about 8 feet away.
Last is of a rock pile with a large white quartz stone in the center. Found near pit/wall/boulder thing.