My eye was attracted to this area on the map before, and the first time I visited here, a few weeks ago, I stayed to the right as I came in from the west on Scott Rd. That brought me to the back of the Audubon parking lot (see here). Later, I realized I had never gotten to a spot (near "a" above) that looked good during planning. So I thought I should go back and check it out. Later I could explore some more of the northern side of the Flat Rock Hill. So, coming in from the west, the same way as before, I stayed sharply right before "a" just behind the houses, so as to get to the top of that little hill there. I saw some rubbish, and then just what I was hoping for: a rectangular mound with a hollow, looking southeast over the water that fills "a".
Photo conditions were not good (too much light and brush cover) but to the left of this photo there was an extension of the pile - a "tail".
The pile from below:and side (now the extension is on the right):In the second picture, you see these rocks towards the middle:closer:I noticed two satellite piles. One to the side:The other behind:After taking a few pictures I explored around the rest of the little hill, saw nothing, and returned to Scott Rd.