Not quite, no. The Mesozoic Era lasted from 251 to 66 million years ago. While 66 my is a long time, there may be human processes which "recycle" materials of p

Not quite, no. The Mesozoic Era lasted from 251 to 66 million years ago. While 66 my is a long time, there may be human processes which "recycle" materials of previous civilizations in ways that make the previous ones harder to discern.