Pilot Grove Hill, Stow

Here is Pilot Grove hill, were I met the police [Click here]. Ironically this is not the hill I thought I was exploring - I meant to visit the little hill in the upper left corner of this map fragment. That is the one I haven't explored yet. In fact Pilot Grove Hill was already explored from the side of the Hale School - all that tresspassing yesterday for nothing. Actually it was not nothing, here are three items next to each other from about where the "H" in "Hill" occurs on the map.

First I saw this rock-on-rock.
From there I looked around and could see a second rock-on-rock about 40 feet away across the hill.
As I walked over there , I passed a wedged rock. According to my theory, that means someone closed up the site. But I do not yet understand this occurance of rock-on-rocks along the same contour of a hill. Is it a trail? Is it a boundary? Except for that last little hill I can say with confidence that every hill near Stow center has rock piles on it.