Comparing A "Signature" Stone Stacking Element Incorporated In Native Stone Walls

Comparing A "Signature" Stone Stacking Element Incorporated In Native Stone Walls

Both of these sites are from the same area of woods, perhaps almost a mile apart, nearby to the headwaters of Echo Lake in MA.

Notice the unique stack-work, both within a larger stone-wall complex (also both w/ nearby cairns.)  Notice the shell-shaped stone placed on both stacks.  Picture 1 has two stones resting on top the shell stone, while Picture 2 has the shell-shaped stone stacked on top of 2 stones (as if equal opposites are being expressed).  

It is obvious that these sites are related, and that stacking stones in this way, we can see a glimpse of a "signature" technique stone-work at play- the same elements and motiffs/ ideas were used/ expressed in creating both stacks of stone, incorporated in pre-colonial stone walls.  Since these stacks of stone are both nearby to swamps/ wet-land and incorporate shell-shaped stones, I am going to guess they have something to do with the spiritual energy, also habitat, of the turtle, an important totem: