One evening, when the sun was low in the west, in an area where I've walked for over 40 years, I noticed that the light from the sun struck an array of rock piles, revealing that many of those rock piles had a white quartz in the center. Returning home, I "googled" "Rock Piles Western Massachusetts."
One web page: "Wildcat Hill Cairns," had photos of a landscape which mirrored the one near where I live.
A description of the "Wildcat Hill Cairns" in Ashland, MA matched the description one could make of the many rock piles in my neighborhood.
"Stone pile sites can be found all over Massachusetts. In some cases, the stones are carefully arranged on top of exposed boulders. In others, they appear loosely piled on the ground. Often, they are found in large clusters of similar appearance. While some may be the result of field clearance, many are found in areas so rocky that “field clearing” would have been futile. There are some early New England accounts of Indians building "donation piles", in which travelers add a stone or stick to a pile to honor an ancestor or local spirit. Elsewhere, stone piles are associated with vision quests. Wildcat Hill, located in Ashland not far from one of John Elliot’s praying villages, may have comprised a ritual landscape with upwards of a hundred devotional cairns, all on the west slope of the hill. If you visit a stone pile site, enjoy the ambience and take care not to disturb any of the rock formations, which contemporary Native Americans believe still carry prayers to Mother Earth."