Carcasses of tyrannosaurs were small, biodegradeable and tasty though, so their preservation was the rare exception rather than the rule. It would be rather harder to miss evidence of industrial cities of tens of millions of people spread across entire continents, many of which have not been subsumed by plates.
Most of the skeletons of the ancient Egyptians aren't found, but their pyramids are very much in evidence, and this was a civilization far too small and unsophisticated to leave obvious traces in the form of global warming.
I don't think we can rule out the possibility that past species used tools and communicated in ways which resemble human language, but if they'd been numerous and advanced enough to disrupt the climate with their Industrial Revolution, one can reasonably assume remnants of some of its products more substantive than evidence of temperature fluctuations or nitrate residues would exist.
Easier to get excited by false positives by widening the search space though: the same geological forces capable of disappearing nations are surely capable of causing temperature anomalies.
Most of the skeletons of the ancient Egyptians aren't found, but their pyramids are very much in evidence, and this was a civilization far too small and unsophisticated to leave obvious traces in the form of global warming.
I don't think we can rule out the possibility that past species used tools and communicated in ways which resemble human language, but if they'd been numerous and advanced enough to disrupt the climate with their Industrial Revolution, one can reasonably assume remnants of some of its products more substantive than evidence of temperature fluctuations or nitrate residues would exist.
Easier to get excited by false positives by widening the search space though: the same geological forces capable of disappearing nations are surely capable of causing temperature anomalies.