I just completed reading the book below on this subject (at SunkenCiv's urging), it was a very good read and I recommend it.
The Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture
I have been watching a 5 part series called ~North American Comet Catastrophe 10,900 BC over on youtube this morning. Firestone and West are on the panel, really interesting viewing.
http://www.youtube.com/watch?v=f1GCgOI3B1o
I just completed reading the book below on this subject (at SunkenCiv's urging), it was a very good read and I recommend it.
The Cycle of Cosmic Catastrophes: How a Stone-Age Comet Changed the Course of World Culture