Earlier quoted context omitted.
Rocks aren't biodegradable. There are buildings in Rome with basements made of Roman concrete. Cemetery land gets reused all of the time. In my city, the main park (1890) and high school (1970) were both built on cemetery land. The land gets seized by eminent domain or purchase, bodies exhumed and rebutted elsewhere.
>Rocks aren't biodegradable. I'm sorry, but what? https://en.wikipedia.org/wiki/Lichen >When growing on mineral surfaces, some lichens slowly decompose their substrate by chemically degrading and physically disrupting the minerals, contributing to the process of weathering by which rocks are gradually turned into soil. While this contribution to weathering is usually benign, it can cause problems for artificial stone…
Near where I live, there are boulders that were dragged down a valley by retreating glaciers 10,000 years ago. They've been exposed to the elements for that time, are are materially intact.