With reference to the map here, let me describe a rock pile site consisting of simple rock-on-rock and minor piles, scattered up a hillside, with perhaps 15 piles like these:
These are beaten down remnants, in a hemlock grove. Let's climb the hill, following the piles on up:Many of them had the appearance of "gap piles" - a simple rock pile a few feet from another rock.Right on up the hill to the highest pile I saw: a simple pile reminiscent of "twins".But the lowest pile on the hill carries a special message, or at least suggests something of key importance:That porthole in the wall, behind the rock pile, is the focus of this spot. It was unmistakable. I have to imagine light passing through that hole.
Sometimes I see these portholes and do not consider them important - they could just be a clever use of a flat "lintel" rock to span a part of the wall efficiently. But such a porthole must have more significance than that. Closely tied to the special properties of this spot.