I think there was a seafaring civilization that was sailing the globe during the ice age. Their cities were on the sea coasts where conditions were warmer.
It is likely the inland inhabitants were less advanced, inhabiting the colder and harsher interior. It was a civilization that went underwater when the ocean levels rose 300 feet in a reletavly short period.
Atlantis was not a place, it is the legend of a time. A time of global climate change that ended a civilization.
Whatever works, use it.
A good idea stands on its own value independent of authorship.
If it stands or falls on the credibility of the author, maybe it isn't such a good idea.