> a rapid increasing in global temperature (and CO2 concentrations) around between 60-50 million years ago

> a civilization like this would not leave a trace on the geological record

Am curious: if dinosaurs can be found with intact skin [1], after 110 million years, why not remains of the civilization's "people" (bones etc.) after 60-50 million years?

1. https://en.wikipedia.org/wiki/Borealopelta