Somebody might notice a lack of elephant teeth above a peculiar boundary, or a reduction in fish bones and corals, and look closer at the boundary. But to notice a lack is much harder than to notice the advent of something new. A layer of paperclips might not attract much attention, once oxidized, or be interpreted with anything like fidelity.
Comments
"Humanity: it was thin but noticeable."
If you were specifically looking for it.
Somebody might notice a lack of elephant teeth above a peculiar boundary, or a reduction in fish bones and corals, and look closer at the boundary. But to notice a lack is much harder than to notice the advent of something new. A layer of paperclips might not attract much attention, once oxidized, or be interpreted with anything like fidelity.