Some old mounds?

In the eleventh hour of the "fall", took a quick walk at Raymond Callahan State Park, and headed to the western edge, where there are open fields behind barbed wire. Sure enough some probable mounds but I could not get a good look from the outside of the fence.
From below:

 From the side

And there was a longer one up at the brow of the hill, still farther from the camera:
From below:

 From the side:

I take it that these might be non-agrarian, because the rocks are uniform in size. But the placement is very agrarian, at the edge of a field.
Note these "mounds" are at the western edge of a valley that has other things on its eastern side, as shown by two red dots:

 

I should mention I once got an angry email from a descendant of Raymond Callahan, correcting my quoting of the topo map - which misnames the park.