1) The structure is
hexagonal.
2) A cistern should be below ground.
3) A kiln would be a simple structure, as in jmen24's photograph.
4) Those are all 2nd-growth, fast-grown, white pines—none of which appear 50-years old.
5) A mausoleum should have a written/engraved indication on the outside.
6) Granite isn't in shortage here.
That leaves (with more possibilities—a possibility
)
1) a statue base
2) lighthouse base
3) windmill base, or
4) A marker of a property corner, connected with the granite wall mentioned.
5) a what-the-heck, shovel-ready, pre-built "ruin".
But for what other reason would the structure's top be
flat?
I'm partial to FLboater's
windmill base for pumping a well previously dug below it.
(If there
is a well below it).
