I was gonna post this: Comets Hit Early Americans, Scientists Say, but, a search revealed that you already had.
Now, you should have pinged me. No-one enjoys a good catastrophe as good as me.
Professor Stephen Oppenheimer, in one of his books, suggests that it may have been comet impacts that began the end of the last Ice Age.
Thanks for the ping, Blam.
NR, I'm right behind Blam in enjoying a good old fashioned catastrophe.
redangus, debuillion, glad to meet ya. :')