evidence of evolution in the bible?

Is this your only reason for supposing that we had a previous advanced culture?You also seem to forget that there is no evidence for a world wide flood so that at least blows your suggestion out of the water (excuse the pun).

There is evidence of floods, that's true: but a world wide flood? I think not.About the snake not having legs: my 10 year old nephew once asked me: "what happened to the snake's legs?". My other 9 old nephew piped up with "They must have fell off".If two kids can surmise that snakes may have had legs it does not mean a great deal that a bronze age man could have thought the same thing. After all most land a imals have legs.Your point about the Sumarian civilizations being after the flood does not hold water as the deluge was mentioned in the Epic of Gilgamesh which a) predates the bible and b) references the deluge as yet to happen.

This sounds very like the plot of one of David Gemmel's 'Sipstrassi' novels.