gleeakin, I think what we’ve got here is a “hunted to extinction” crusader. I sent him/her to some links that are pretty compelling re a catastrophic end to the Pleistocene and I’m guessing he/she got a painful whiplash turning away from it. Not only that but evidence of simultaneous megafauna extinctions in other parts of the world besides the Americas which he/she also ignored. I’m also wondering if he/she has read there has been few, if any, human artifacts found dating to within a thousand years or so AFTER the events that took out the megafauna. Indicating of course that whatever snuffed the megafauna likely also snuffed most of the peoples of at least North America. Don’t know about the rest of the world.
Having read the book that Sunken Civ has posted on this thread, I am inclined to think it was something more solid that a comet, or else a very large one, perhaps a broken up asteroid. For example, there is a picture of the bottom of Lake Michigan which appears to have been hit by either 2 or 3 large objects in a row. There is also evidence of some things striking Siberia or Scandinavia.
The early Australians had many tens of thousands of years to kill the mega fauna. They also may have killed off a pre sapiens homonid about 12,000 years ago called Kow swamp people. In the wall of human evolution in the Smithsonian one of the Kow skulls is in the far right lower corner. It is called homo sapien, but after comparing it to Neanderthal and earlier Heidelbergensis skulls, I am of the opinion it had more in common with the Heidelberg skulls. Really, the only basis for calling it sapiens is the 12,000 age. when the Europeans arrived in Australia the Tasmanian Devil and Tiger were still alive, and I believe other large animals that are now extinct had survived the aboriginies. They did not survive firearms. There are still significant killings and species depletion occurring in Madagascar as well.