@ Sail Away
I have heard the whole "erased memory" statement before actually! Funnily enough, a friend of mine who is not a JW, had a step-mother who was one (an abusive woman, as I am told) and she asked this very question about what would happen, how could you be happy if you'd lost someone "to the world" as it were. And the mothers reply was that "we would forget them, in order to be happy."
And honestly when I heard it, I cried! I can't believe a God who has given us the capacity to love with such conviction, to form such strong bonds with one another & are encouraged to "love thy neighbor" would wipe away a person from our memory, just for a false sense of happiness.
My mother was taught by her father (my grandfather) that well... we don't really know. That they probably were all washed away in the the great flood, but when I pried her and asked "well what about the dinosaurs who were small enough to fit on the ark? what about the sea-dwelling dinosaurs" and her response was "we just don't know! perhaps the 'whale' that swallowed Jonah was really an ancient sea-dweller that isn't around today!"
I didn't ask any further, but I was confused, if giant sea-dwelling dinosaurs were still around during Jonah's time, surely there would be more records of them, and surely we'd find remains of them!