Jocelyn Hill - North Leominster

Went out with the ladies from Harvard and one of the places we checked was Jocelyn Hill in North Leominster. For some reason, when I first saw the rock piles along the southwestern brow of the hill, I thought they looked sort of random and "rock disposal"-y. But when I got home I realized they were more systematic and "mound"-y. This picture from Sydney Blackwell helps to see it:

In the foreground is one rock pile. It has a rectangular outline and a diagonal of smaller rocks cutting across the right hand corner. Gail Coolidge is standing below it and to the right of a second rock pile that is also somewhat rectangular. The compelling observation (for me) is that the two piles, as rectangles, are oriented in the same way, making the same angle with the slope - like tiered boxes. You can try interpreting the even messier piles beyond in that light. Now that I see it, I think these are clearly what is left of deliberate rectangular mounds.
Closeup of the first one - look at the details:

Closeup of the second one:

Now that you see the rectangularity and the hollow in the middle, you realize this is a very typical design (for burial mounds).
Here is a smaller auxiliary pile - which also should have made me realize this site is not about rock disposal:

A few other views:

Added:

For clarification, here is what I mean about pile orientation:

As I look at the pictures I see other details, the last photo and the one two before it are hard to tell apart - with the same large rock tumbled off the lower edge. But those are different piles. Also, if you look at the lower edge of the "structure" in the 2nd picture with Gail, it forms a zig-zag continuing the perception of a common orientation for the whole collection of piles.