While there is a nice webcomic with a similar theme, I'm talking about a hopefully more reliable claim: The Science of Discworld alternates between chapters written by fantasy author Terry Pratchett about the fantasy setting of the Discworld's wizards having (accidentally) created Earth inside a glass bowl and observing its evolution fast forwarded, and chapters written by mathematician Ian Stewart and biologist Jack Cohen trying to elaborate on the scientific part of the respective epoch.
Now while one of the fantasy chapters describes a pre-human (in fact, some large lizards, you know, dinosaurs) civilization that is then extinguished by a meteor (and was made-up for all we know), the following scientific chapter states the following (bold emphasis mine):
In order not to mislead you, we should point out at once that there is no scientific evidence for the existence of any dinosaur civilization, no matter what events are going on in the Roundworld Project. But... whenever a scientist says 'there is no scientific evidence for', there are three important questions you should ask -especially if it's a government scientist. These are: 'Is there any evidence against?, 'Has anyone looked?', and 'If they did, would they expect to find anything?'
The answers here are 'no,' 'no', and 'no'. Deep Time hides a lot, especially when it's assisted by continental movement, the bulldozing ice sheets, volcanic action and the occasional doomed asteroid. There are few surviving human artefacts more than ten thousand years old, and if we died out today, the only evidence of our civilization that might survive for a million years would be a few dead probes in deep space and various bits of debris on the Moon. Sixty-five million? Not a chance. So although a dinosaurian civilization is pure fantasy, or, rather, pure speculation, we can't rule it out absolutely. As for dinosaurs who were sufficiently advanced to use tools, herd other dinosaurs ... well, Deep Time would wash over them without a ripple.
So, is that true? Would the civilization of mankind, once perished for a million years, leave no traces more noticeable than the dinosaurs' bones are to us nowadays?