Brief visit to Ponkapaug

The woods across the highway from Blue Hill have always looked interesting. Full of big dark red rocks of the -so called- Wamsutta formation (see here). I took a brief spin over there last weekend and found very little worth mentioning. But you see little hints.
With the tips of these three rocks lined up, and two of them having artificial-looking notches, could they be intended to line up?

They do:

A horned owl?

Is this something?

Something going on here: