“before the Diluvian Flood of mythological and Biblical lore.”
An important point. Based on Geological fact and science the Deluge was a real thing and was not Mythical. It is one of those events where science supports the oral and written traditions around the world.
Plus just about every culture on earth has a flood scenario in its mythology. That can’t be coincidence. And if you look at satellite maps of North Africa, you can clearly see evidence of massive flooding all across the Sahara, going east to west across the whole thing and into the sea.