Northern Kissacook Hill - Westford, MA

I found a site here on the northwest side of the hill at a place where water comes out of the hill. I have walked past this place at least twice before without seeing anything. As I look at the piles, badly damaged though they are, they remind me of the favorite sites elsewhere in Westford and in Bolton where water comes out of the ground.
I walked over there thinking I would explore Clay Pit Hill but I had forgotten the reason we had not been there before: it is a shooting range. I had to keep the sound of gunfire to my left and, at one point, I thought I was not more than a short thousand yards from a shooter. But I was also close to houses so I was confident the gunfire would not be directed towards me.

Anyway, I have been over there on the north side of the hill and seen an unusually tall rock-on-rock.
A few few feet uphill from it, in the midst of an active breakout zone and boulder field, there were a number of very broken down piles.
Here are some slightly better preserved ones:
And here they are at their densest in the breakout zone:
What a mess. There were a lot of rock-on-rock which could have been simply all that was left of a pile. There were also numerous shadowy overhangs that could have been deliberate or the result of things falling over.
Many of the piles were close together making me pause and wonder if they were actually just tumbled over stone wall. But they are offset from each other, reminiscent of short stretches of wall we have seen lately at other places where water comes out of the ground: