[From reader James O.]

A few weeks ago I bushwhacked some distance to a relatively inaccessible ridgeline in Harvard along 495. I felt pretty happy with my site-selection once I reached the top of the hill, where I found some very distinct rock piles. 

Farther down the ridge, I found what looks like a small stone chamber built against the protruding bedrock. Not big enough to enter, but if you stick your head in you are greeted with a sky-light.