Rocky Hill Chelmsford

Here are some scenes from Rocky Hill in Chelmsford, which is a high hill with a water tower on top, along Turnpike Rd. The hill is surrounded by residences and businesses but there is a thin corridor to explore on the west side. Near the top, this pair of rocks together might be an aperture pile. As you go down the west side there are several propped rocks, some pointed, some standard boulders, in patterns that reminded me of Bruce's Holliston Town Forest.
The manipulations are faint but slightly familiar.

A little further down the west side was this rock-on-rock arrangement:
I was noticing the shadows and the late afternoon sunlight against the flat fronted triangular rock in the midground in this picture. It was 4:37. I was thinking that as the year progresses further into summer there might be a better and better chance for the sun to pass over the 'V' shaped notch in the rock in the foreground and project onto that nice trangular surface. Flat triangular rock surfaces against which the afternoon sun projects are also featured at Holliston Town Forest.

Then more on the south or southwestern side of the hill, there were several low ground piles which I could not convince myself were "genuine". But then here is one I have a hard time dismissing completely and also because of its relation to the cracked boulder in the background.
Here is a detail of the cracked boulder:
It is possible there was a small site back here and this is just what it looks like when it has been in someones back yard long enough. But I am still not sure.