This week's discoveries much like the last

I continue with the hunting strategy of finding navigable brooks with tributaries leading up hill to where the water first begins to flow. This "where the water meets the sky" has been a good strategy. Perhaps it is leading me to see more of one kind of site that another - biasing the reports towards that kind of site. At least in northern parts, I hope to find larger rectangular mounds with hollows at this sort of place. But the last several weeks I have been finding marker piles. I followed the strategy to some sites in Sherborn. This weekend the strategy worked in Princeton, west of Wachusett; and also in Townsend. So I have three other marker pile sites at the tops of brooks. Interestingly, the individual rock piles, west of Wachusett, were shaped differently, but the site layout is familiar.
Here from Princeton:

 Compare with Sherborn.