From a USA Today article:
"Most of the skeptics I have read are of the 'Atlantis is impossible' variety, and have never done any exploration in the area at all," says Doug Richards, a geologist who has carried out research and written papers for the Meridian Institute, a Virginia Beach, Va., organization that sponsors research into the connection between mind and body. "I think that most likely it is a natural formation, but neither side of the debate has done the work necessary to prove it one way or the other."
Richards says at least part of the Bimini Road may be man-made. "For example, there are large stones balanced on top of smaller stones," he says. "Beachrock does not form that way naturally, so if it is beachrock, it appears to have been moved by humans. There is also a circle of stones that looks nothing like a natural beachrock formation."