Northermost Townsend State Forest - part 3: The very tip of the Nissitisset Watershed, on the edge of Mason, NH

continuing from here.

At the very highest point of the Wallace Brook watershed (at the northenmost point on the large blue outline above) I did see some isolated short stretches of stone wall. They are a kind of rock pile.
Here are two of them:

And let me re-post the one from a few hundred yards to the south in Massachusetts: