Woodbridge 3 - "Crescent Cairn" at Elderslie Preserve

The main Woodbridge experience is within the "Elderslie Preserve". Check out the nice Woodbridge Trail maps. They indicate this feature and I was expecting a wide old crescent remnant of a mound with hollow. But no, this was more like an oven:

Here are some photos:

Note quartz in the corner:

Note the amount of soil eroded away below the structure.

I would say this is a unique structure but I have seen something very similar before, behind the main school building at Barlow School in Amenia, New York. The school is gone but I suppose the rock pile is still there:

See here.

This example in Woodbridge, off Orchard Rd, seemed blackened on the inside - which is why I suggest it is some kind of oven. But I do not know. I was struck, in Woodbridge, by how much soil had eroded from around the base of the structure.