The major and recurring difficulty in this discussion on Atlantis is that some folks want to rely on "mystical speculation" based on visions -- such as those of Cayce -- and some folks want to see "science." My problem with mystical speculation is that it cannot be independently verified using generally accepted scientific data gathering and analytical techniques.

There is NO archaeological data or geological data to support the conclusion that there ever was a large island -- let alone a continent -- in the Mediterannean basin or in the Atlantic "beyond the Pillars of Herakles."

That there may have been "something" that formed the basis of the myth of Atlantis as recounted by Plato I'm willing to grant. But not a continent that has now sunken and disappeared. (Maybe the break up of Thera into the Santorini Islands could account for such a story, but I see nothing else in the scientific literature that could be a candidate.)

As interesting as the speculations of Donnelly and Cayce may be, they simply are not scientifically verifiable. They are factual assertions with no factual data base to support them.