Sites with a central "mound" - part 1

I want to describe three sites I saw over the last two weekends. One site in Wolf Swamp Boxborough had an old smeared out "mound" near the center with a very irregular shape, surrounded by a number of rock-on-rocks and low rock piles, as well as a row of stones leading off in one direction for a few yards. The other two sites are from Leominster: the one being just a single smeared out "mound" near a larger rock, with an irregular shape to the mound; and the other consisting of a low "mound" with a distinct rectangular hollow, surrounded by rock-on-rocks and a few "ski-jump" piles. In each case the mound is near the center of activity and with an irregular outline, as seen from above.

Attention to the idea of "rock piles with tails" has led to paying closer attention to such central mounds, even when they are not the most dramatic or well-preserved piles at a rock pile site. Also now, I am paying closer attention to how things are layed out around this central mound. Since I am of the opinion that these mounds with hollows represent burials and since I am of the opinion that things like ski-jumps and short stone rows are related to sky watching; so I am starting to believe these three recent sites are similar and combine something funerary with something astronomical. That's my fantasy but you can judge for yourself whether these "mounds" have anything in common. I asked a colleague one time, how many different types of rituals could be represented by the different types of rock pile sites. He said "infinite". Although I agree there is validity to the view that "no two snowflakes are alike" for rock pile sites, I think it is an anti-scientific attitude. I am looking for similarities and common patterns.

Wolf Swamp conservation land in Boxoborough has a couple of turnouts where you can park. At one, I explored across the street rather than going into the conservation land. I found a wetland and noticed a couple of rock-on-rocks:Then I noticed something larger and pretty old (based on its degree of smearing and its debris cover). I was quite taken with this and took a number of pictures:
In the 2nd and 3rd pictures you can see the irregularity of the piles shape. In particular in the 3d picture, you almost sense two lower dips in the height of the pile. These could be the "hollows" I have been noticing in some larger piles recently.

Nearby this large pile another few piles, maybe a "gap" pile (note the gap opens towards the large mound):A pile with some larger flat rocks:A bit of an "alignment" formed by a loose stone row:
And some slightly larger, "vertical-sided" piles on the other side of the large mound:
Seeing these as "vertical-sided" is a stretch but I think this is generically similar to the "ski-jump" piles we'll see at one of the Leominster sites. Also worth noticing is that these slightly larger piles are all on one side of the central mound and the minor rock-on-rocks and smaller piles are on other sides of the central mound.

Finally, here is the kind of rock pile you don't see unless you are looking for it: