"The "golden age" is a myth, but Eden was a fact, and the Garden civilization was actually overthrown. Adam and Eve carried on in the Garden for one hundred and seventeen years when, through the impatience of Eve and the errors of judgment of Adam, they presumed to turn aside from the ordained way, speedily bringing disaster upon themselves and ruinous retardation upon the developmental progression of all Urantia(Earth)."
[74:8.14] 

"One hundred and sixty-two years after the rebellion a tidal wave swept up over Dalamatia("Atlantis"), and the planetary headquarters sank beneath the waters of the sea, and this land did not again emerge until almost every vestige of the noble culture of those splendid ages had been obliterated."
[67:5.4] 

"... as the Hebrew priests in Babylonian captivity sought to trace the Jewish people back to Adam, they found great difficulty in piecing the story together; and it occurred to one of them to abandon the effort, to let the whole world drown in its wickedness at the time of Noah's flood, and thus to be in a better position to trace Abraham right back to one of the three surviving sons of Noah."
[78:7.3] 

"That the earlier traditions recognized pre-Adamic civilization is clearly shown by the fact that later editors, intending to eradicate all reference to human affairs before Adam's time, neglected to remove the telltale reference to Cain's emigration to the "land of Nod," where he took himself a wife."
[74:8.8]