Stone niche - in context

I want to show a few other pictures of the place, off Rocky Hill Rd in Groton MA, where I found the stone "niche" I posted the other day. It was adjacent to another small rock pile:This occured on the southern/western facing sides of a low ridge, looking over a slight valley to another parallel ridge a hundred yards away. Exploring that other ridge is for another day. Meanwhile, there were a couple of other piles in the same general position a bit down the (first) ridge from this niche. Here are some of them:The whole area was scattered with small clusters of ceremonial structures. Across the road was the older site I described here.