Adopting caves as homes by the descendants of Prophet Adam (pbuh) is something the Quran confirms.  Yet, since there is substantial evidence that there have also been people before him and we are sure there have been ancient people who have lived in caves, it is up to different clues, their remains and the drawings and writings they have left behind to exactly determine in what era they lived in.

What is for sure is that Prophet Adam’s (pbuh) time doesn’t belong to a very long time back.