you can easily see this continental shelf-break on google earth or other cards.This is the ancient level of the ocean.
12.000 years ago, ocean was 170m lower. 8000 years ago, it was 70m lower.
At this time, the english channel was a land, and we can find some villages on the bottom of the sea and a gigariver that was the jonction of lots of rivers from north of europe.
But i never heard that the level of ocean was 300m higher than today (that would mean 470m more than 12.000 years ago).
But 170m higher is a lot for any civilzation on earth. You can catch plague for less
![:)](./images/smilies/icon_smile.gif)
And we're are crying for 3cm more "maybe" in a century lol
I think those 170m was not anthropic
![:)](./images/smilies/icon_smile.gif)
Look at what we've done in the last 3000 years...we went to the moon !! (lol)
So imagine what can have been done since human kind is on earth, and calculate the probability that advanced civilations have occured, even without lots of evidences.