Cairns on a hill

Here is a  hill crowned with interesting structures, that  I visited in the winter of  2010. 
On top of this hill is a foundation for a small building, which would have been surrounded by these structures.  This site is about 1000 feet south of  the  boulders aligned to winter solstice that I showed  12/22/2011. The bearing would  be about 155 degrees, but since  I don't know the vantage point for winter solstice, I can't be precise.

     Here are photos taken at this strange site on a cold winter afternoon.  Next to the trail uphill from the main road is this slab resting against a boulder, which  was produced by quarrying.

 

At the top of the trail stands this propped boulder on bedrock, pointing southwest.

Nearby are two boulders linked by a short chain of rocks.

There is still some debris and trash left over from the demolition of the house.  The house was up here until fairly recently, since it is marked on topo maps from the 1960s.  Small building foundations  are often present in areas with cairns and other structures. It is possible that  Indians remained in  these areas because of their significance, or they were marginalized to this rocky farmland.
     A wash tub rests in front of another  propped boulder.

 Here is a closer look at the propped boulder.  The tub is out of the picture.

There are many  platform cairns, and

 a massive pile of large rocks

There is a steep pile of boulders on the hill, which seems to be the focal point of the site. Perhaps it was once a landmark.

     Why would anyone pile rocks on top of a hill?
The short answer: they were already there, left by the glaciers.  These boulder-hills and rocky slopes are common in RI, and often have cairns, manitous, propped boulders and other structures nearby. So what is the purpose of the rock piles?

    Maybe there's a hint in the first picture, which indicates quarrying.  The rocks in these piles range from boulders to fist-sized.  The abundance of large  boulders made it an attractive quarrying site, and the rocks were sorted into different piles by size.  Here is a boulder that seems to be partially broken into relatively uniform pieces. There don't seem to be any tool marks, or the very straight edges typical of settler quarrying of boulders.

Some of these sites may have first been used as quarries by the Indians, and then by the settlers, who left some of the Indian features intact.  Perhaps the original purpose of the quarries was to produce stones with flat faces for stacking into cairns and stone rows. The labor in producing these stones could have been considered devotion or sacrifice.
     Here is a view of this hill from the west, before the area was overgrown. These hills crowned with boulders must have been an impressive sight in the late afternoon sun.  In the foreground, a propped boulder stands outside a wall.  The area at the foot of the hill is swamp.  The pile of boulders is to the far right on the crest of the hill, and another collection of massive boulders is left of center. The winter solstice site is barely visible between these two landmarks.