In working on this set for the Underwater Landscape contest (http://www.polyvore.com/cgi/contest.show?id=496535&type=entries, ) I ran across this interesting guy :
----- Jason deCaires Taylor ------
He creates underwater figures which can be used by nature to create an underwater reef. Here's a link to his work: http://guliverlooks.wordpress.com/2014/02/07/the-work-of-jason-decaires-taylor/
I can imagine these figures as being from Atlantis.