Phillips Hill, Hudson MA

I have been over here before but not to this hill or, in particular, its southern parts. Parked on Rt 85, went in and turned left (south) intending to look around that little pond you see on the map. When I got to the place circled in blue, I thought: "well this would be the place...where are the rock piles?". Here was one:

But I was disappointed to not see any rectangular mounds with hollows. Since this is the headwater of some brook (I could not figure out which one, as it seems to have been buried underneath downtown Hudson). Anyway, in the end I was not disappointed: there was only one mound and it was made of soil, not rocks.
As fine an example as you could hope to see:

No that is not a house foundation - there is water at the bottom of the hole.

And nearby, at the edge of the water:

Again:

There was also another lobe of land just to the east that also looked out over the pond. It seemed too well visited to spend time examining but this did catch my eye:

Then I headed sharply uphill, skirting the end of a road and found marker piles all the way up the slope and some older looking "rectangles" on the flat summit/shoulder looking out to the south.
For example on the slope:

Further up (note some of the details here: the larger rock, the cashew shaped smaller rock, the swirl of schist):

We are still climbing the hill and the trail goes right through the rock piles. [How many hikers have ever noticed? Zero?]

This is much more than I expected to squeeze out of a small bit of the landscape - so near Hudson and at the edge of an area - around Marlboro and Southboro (and all those "boros") - that is a real dead zone for finding rock piles. Let me digress to say that this dead zone may be due to the fact that the towns around Marlboro are sandy. But I wonder about a cultural divide that separates Nashoba and Upper Middlesex (my version of Thoreau's Estabrook) from the towns around Holliston, Hopkinton, and Upton (we could call them the "tons") where the ceremonial stonework could be seen as different. I am not sure if it is different enough to support the idea of a cultural divide. I am not sure the Nashua and Merrimack watersheds are different from the watersheds that drain more to the south, nor if these differences are a projection; nor if those places have enough uniformity within themselves to be characterized this way. Yet I think there is a difference.

Ah! Here we are on the southern end of the summit:

I think this next one is a different, older kind of rectangle, with a double "hollow".

These are exactly the sorts of things that I am not sure I see much of - further south in the "tons". But Scott Reservoir, Cowassock Woods, Briar Ridge Rd Acton, maybe Kezar Hill? And the stuff about "lazy 9".
Again

You can see why I think it counts as a "rectangle" and there is a hint of inner wall dividing it in two. There was at least one other similar thing up there, I did not get good pictures:

And a bit east around the side of the hilltop, some more marker pile-like items:

A lot more than I expected to find. Clearly those hills were crucial real estate for ceremony: