Foot of Blodgett Hill - Merrimack NH

I should probably not drive so far, or find a better way to get there. I took a short walk at the Horse Hill Conservation Land in Merrimack New Hampshire and saw a couple of larger rock piles, one on the way in and one on the way out. Near the first left hand turn off the main trail in:

Not much to say about this. You see remnants of structure in the last picture.

A bit east of there, also in the lower slopes of the Blodgett Hill was this one (repeating a picture):

Note the manitou stone in the wall. Also notice the large boulders that are on the right edge of that large mound in back. As far as I could tell, these larger rocks are part of a modern dumping that ended up on top of an older burial mound. So at times, I hope you can discount some of the largest rocks strewn about. 

I see two hollows: left-and-back and right-and-front of the picture's center. We'll walk around it. Seen from this corner, again note larger junk in the background:

And note the vague sense of rectangularity. Not much hope of making sense of it:

At the corner across from where we started:

You can see there's structure. Too bad it is a mess. Here is a last closeup of the hollows:

This is consistent with other areas adjacent the Merrimack River and I assume we can find these mounds all up and down it's watershed.