[Auntie Dem]

How can a stone wall be accurately dated? There is likely no organic material in the wall to make Carbon 14 dating possible, and accumulation of coral or other sea water accumulations could vary greatly depending upon the amount of minerals or aquatic life in the area over the "eons" of time. While I don't believe the earth is only 6,000 years old, I am sceptical of claims of man's presence 15,000 years or more ago.

Of course I guess it is possible the divers may discover an ancient Palm Pilot in the wall whose clock is stopped at 10,000 B.C.

[blam]

Auntie, you need to get out more often. (smile)

Calico: A 200,000-Year Old Site In The Americas?

[RightWhale]

How can a stone wall be accurately dated?

That is the big question. If the wall is submerged now it can at least be dated to when it was last above water, making some assumptions. But inorganic ruins by themselves would have to be dated by association with other objects and materials. If they find a piece of wood, there is the chance of using dendrochronology, a powerful new tool.