Contend that places as diverse as Britain, the Andes, Iraq, and Australia were swept by a tsunami with a height of 5km in 7640BC......
By the way, blam, have you read this book? I'm reading it now....I think you'd like it.
http://www.amazon.com/Uriels-Machine-Uncovering-Stonehenge-Civilization/dp/193141274X
IMO, that would be a good period to be looking for them.
No thanks...it's fiction.