A Corner with Directional Alignments

Most of the groups of  propped boulders I have been showing do not seem to have any astronomical alignments.  One pair of propped boulders had a N-S alignment (7/24/2013).  Here is a small lakeside area in which the propped boulders seem to have alignments to the cardinal directions.

Waypoint 1857. This is the boulder to the north.

500 feet away to the south is  this impressive propped boulder, at waypoint 2134.  It is the corner, and rests on two supporting rocks, a style seen in other sites (11/13/2013, 9/4/2013).

677 feet away to the west is this propped boulder at  waypoint 1862 . There is a small stone wedged underneath it.

This area has many boulders, but the ones that have been modified seem to form lines and triangular enclosures. The lake in the diagram is dammed, so hundreds of years ago, there would have been a much smaller pond and a larger swampy area. Since these propped boulder enclosures are usually uphill from water, they may have been part of Native settlements.