The trope of an ancient advanced civilisation that disappeared is as old as the hills, but it does raise an interesting question: what kinds of evidence would suggest that somebody else was here first? After a few hundred years, most buildings, bridges, and other structures would have collapsed, and after a few thousand there are likely to be only fragments. After a million years or more, is anything likely to remain? Humanity has made such a huge impact on the Earth that even a million years after we're gone, surely something will remain; I can't think of a way that buried reinforced concrete "rocks" could've formed naturally, for example.

I'm toying with the idea that a prior, [sufficiently advanced](http://tvtropes.org/pmwiki/pmwiki.php/Main/SufficientlyAdvancedAlien), civilisation disappeared in some kind of cataclysm at least a hundred thousand years ago, preferably more. I don't want there to be any ruined buildings or monuments, but I'm ok with the extremely rare [magical artifact](http://tvtropes.org/pmwiki/pmwiki.php/Main/ClarkesThirdLaw). I don't know exactly what kinds of technologies and abilities these peoples had, other than that they were probably equivalent to a Kardashev Type I or II. I do like the idea that they were capable of performing geological scale engineering or terraforming because that's a nice little *deus ex machina* to conceal my map-drawing abilities—the in-universe hint would be that the dates from radiocarbon dating and supposed geological timescales required for mountain building just don't add up. 

On the surface, it feels like lazy worldbuilding, but I want to turn that trope on its head somewhat. To prevent this question from being too broad, I want to limit the evidence to be geological in origin (so if there's a partially-complete Dyson sphere around the sun, it hasn't been discovered yet).