It was Purgatory Chasm State Park in Sutton, MA. This is a chasm containing massive stone blocks that were tumbled in by meltwater from the last glacier. It is 70 feet deep and about a quarter of a mile long. Purgatory is an appropriate name, since it is a difficult hike over all those massive blocks, and the chasm has been the scene of a few deaths and plenty of injuries.
Purgatory Chasm is a very impressive place, suggesting the power of nature. Even on a warm day it was quite cool inside, with some ice remaining under the boulders.
Some of the cliffs resemble eagles or other animals.
In all this jumble of boulders, it was hard to find any large propped boulders or manitous. However, there were a few interesting small details.
Perhaps this is a niche on the south side above the chasm.
A young bent tree points towards Purgatory brook.
Here is a mortar that was used by the Nipmucs.
I found an old image of the sign that was behind it, which states this mortar was originally on a knoll near Lackey Dam, and was moved here by some community organization. Close by is Slanted Rock, which the kids were using as a slide.
Despite the sign, I can still imagine the Nipmuc mothers using the mortar, and being able to keep an eye on the kids at play.