> A quick search on "rock weathering depth per century"

That's a great illustration of what I meant. Of course an exposed rock consumes away in the space of a few millennia- this is exactly where the "Silurian theory" comes from. Yet it's also obvious that we have plenty of perfectly conserved rocks that are intact after hundreds of millions of years- i.e. fossils. Any small sculpture buried in clay can survive for an eternity.

> What do those findings tell you about the cognitive abilities and social organization

Skin? Like, with clothes on, or the shape of clothes? And shoes and hiking gear? Footprints with the shape of boots? Drawings "I LOVE YOU" in the sand? The shape of a coca-cola bottle buried in solidified clay? Come on...