This makes the things much clear for the people who had doubts regarding his words. This is one good article.
The ancient artifacts under the sea reminds me of the one known to many as the Lemurian civilization and known to few in Tamil as Kumari kandam. But the ancient tamil literatures dating back to 5000BC and ever further back, describes the and that once connected India, Australia and Madagascar (Indo-Australian tectonic plate).
Catastrophes of the past: poetic exaggeration or scientific facts ?. And similar incident(tsunami) has been described in the epic "Mahabharat" as that which occured at the end of the great war.