King Philip's Cave

King Philip's Cave in Sharon, MA, is a structure of massive boulders that has astronomical alignments.  It is thought to have been used by Native Americans for determining solstices. Some of the stones show chipped edges, suggesting they were adjusted for correct alignment.  This site was the subject of an intensive study by Ballard and Mavor (2006) here.    I  recently visited this site and took many photographs.
     Here is an overview of the structure, approaching from the south.

 This is the view from the north.

Here is the opening for summer solstice, with the bisecting boulder in the center.  Note how the edges are chipped.

There is enough room for an adult to squeeze past this boulder. At the back of the chamber is a large slab that has been  chipped to make a triangular opening where it touches the ceiling.  The back of the next chamber is visible through this opening.

A nice view of the bisecting boulder on the way out.

Here is the opening for winter solstice.

This is the same slab which appears in the article, but the picture angle is slightly different.  There is more graffiti, and  someone touched up the swastika.

There are other interesting structures in the area, such as this huge propped boulder.  This may be the one that the Sharon Conservancy trail guide calls "Moon Rock" because of lunar standstill alignments. What is most impressive about this site is the level of mathematical skill required to create aligned structures  to mark fleeting yearly occurrences. 

 A nearby hill has more structures with alignments, but too many for one afternoon!