A Large Hilltop Alignment of Propped Boulders

     In previous posts, I have described how, on a hill crowned with large boulders, only one, two or a few are propped.  Some of these propped boulders appear to align on a direct N-S axis (7/24/2013), or may appear to form two lines intersecting at an oblique angle  (3/14/2012).  This summer I have spent some time reviewing waypoints on topo maps, and have found  a possible rationale behind the selection of  which boulders to prop.  In some hilltop sites, the propped boulders are on two long lines,  making a nearly right angle.  This may even have been meant as a triangular enclosure, as suggested by Mary Gage in her "A Handbook of Stone Structures" (page 39). In other sites, there are rectangular areas outlined by propped boulders.
     Here is a large group of aligned propped boulders, situated on a high hill in northern RI.  The propped boulders are yellow and joined by a yellow dashed line.

Starting at the left  (west) of the diagram, the first line has two segments.  The longer segment is  491 feet long and has a bearing of 293 degrees.   The shorter segment  is 198 feet and  328 degrees.  To the right (east), the second line  is  310 feet long and about 32 degrees.  They meet at waypoint  1866 at a nearly 90 degree angle. The turquoise waypoint is a massive perched boulder.
     Here are the boulders at the waypoints, starting from left to right. These photographs and waypoints were made in November 2011.  At the time, I had no idea there was any linear alignment, and was recording every propped boulder at the site.

Waypoint 1873, a  group of boulders on an outcrop.  The large boulder to the back is propped.

 The smaller boulder to the front of this group is also  propped.

Waypoint 1874,  another propped boulder.

Waypoint 1870,  a large propped boulder. Planes on the underside of this boulder show where stone has been chipped away.

Waypoint 1868,  a  propped boulder resting against an outcrop.

Waypoint 1866. This is the intersection of the two lines.  The propped boulder rests on two slabs, with an open space in the middle. Perhaps there is some symbolism in this configuration.

Waypoint 1930,  a large propped boulder with daylight visible underneath.

It looks like someone has chipped stone away from the bottom edge of this boulder.

Waypoint 1880. The end of the second line.

 It looks like some rock has been worked away to make small slabs, visible to the right..

  Waypoint 1869 in turquoise is a prominent perched rock,  well known in this area. The long axis faces 105 degrees, and would point to the corner boulder at waypoint 1866.

        There may be other ways to line up these boulders, but it is striking how closely they form two arms of a right angle, overlooking  the south slope of this broad hill.  There do not seem to be any astronomical alignments. This could have  been a triangle enclosure, although there are no propped boulders remaining along the third leg. Perhaps this was once part of a  boundary around a campsite or ceremonial site. It would have had a commanding view to the south.  I hope to return to this site in the winter, and examine these boulders more closely.