I'm a troglodyte by nature...in fact that's what I named my home for the last ten years while I owned it..
it was a mobile home.

A Kenworth W900 500hp 18speed 4axel Diesel semi tractor. Warn't nothing it couldn't pull. And I lived in it for a decade..by my self.

that said..
18K years ago the ocean level was 400 foot lower than it is today..that left a LOT of continental shelf available to live on. Man has always lived along the shore.
SO...I suspect that the vast majority of what was happening back then...
...is underwater.

We basically have NO CLUE..and are basing our speculation on outliers..