I revisited the double boulder site I posted last week (1/23/2013) to see if there were any other alignments. Assuming that boulders with alignments are marked with small round holes, I checked this boulder.
Perhaps the single hole means moon. It is about one inch deep.
Directly to the left of this boulder is this large split boulder.
The face of the split boulder has also been marked with a chisel.
The alignment parallel to the smooth face is 310 degrees, suggesting lunar standstill. Observing the moon on the horizon by sighting along the smooth rock face would be fairly accurate, especially since there is only a low swampy area in this direction.
The bearing facing from the split boulder towards the double boulders is 130 degrees. Maybe lunar standstill moonrise is observed over the peak formed by the two boulders.