More on that Southborough site I was talking about

So I came down right into the edge of the wetland and noticed a collection of flat rocks propped against supports. Let's take a look at the shapes of these flat propped up rocks. You can see that the nearest one, on the left in the picture above, is a bit "manitou" shaped. How about these two: These are all within a few yards from each other. I noticed a split-wedged rock: And here is what looks to me like the heart of the mystery: The spring.