Dry Plate - Sacrificial Rock

Or a lye-leaching stone common to 18th- and 19th-Century farms in North America.

I suppose if you make a mistake handling lye, you would become a sacrifice...

I like how the alteration on the slab surface and the non-natural stacking of the rocks is just there, and not over-emphasized. As someone with a geological background I am always interested in how the landscape is modified by people.