Under the power lines on Baralock Hill, Groton

I had tried to get north of this hill via a road that turned out to be "private" and closed off. So I went around to where I spotted a conservation land entrance, which took me up the west side of Baralock hill. Just walking along: what is that?

Not the clearest "mound", could it be modern or ancient? Lots of reasons why it is ancient: Two things jump out: the consistent small sized rocks involved and this faint hollow with most of the visible quartz at its edge. Also the fine view over water:

Let's get a close up of that faint depression (where there is slightly more snow on the pile).

The only obvious quartz is around this depression, on the far and near edges:

That was pleasant and unexpected. 

So I continued up the power lines and came across another old smeared out rock piled. (I joke that this is exactly what a 2 thousand year old Sythian burial looks like from Siberia. I guess they had a lot of colonial field clearing going on back then.) Here are some views of the second mound:

Reasonably rectangular (actually I think the Sythian burials are more circular)

A view back toward the first pile (under the single pole)

Even though all smeared out, you can see how this was a substantial taller structure:

Both this and the first mound have views down the hill to the south over the marsh - which is a headwater of Unkety Brook. I note that the setting of this second upper mound, is in a bit of a natural amphitheater. That might be relevant:

I would not make such a big deal of these piles but they were all I found that day. My original plan had me walking past lots of sandy paces.