Back in the 1970s, a mastodon skeleton was excavated near Manis, Washington. The skeleton had a strange feature: a stray bone fragment seems to be sticking into one of the rib bones. The excavator, Carl Gustafson, dated the mastodon to around 14,000 years ago and speculated that the bone fragment might be a human-made spear point. There the matter rested for 35 years, just another unexplained anomaly in a world full of them.
Then along came archaeologist Michael Waters of the University of Texas, a big believer in "pre-Clovis" (before 13,300 years ago) humans in the Americas. Waters had the specimens redated using modern methods and used a CT scan machine to image bone fragment. The fragment has not been removed from the surrounding bone, which would require destroying the specimen, but the scan (bottom left image above) does make it look like a bone point.
And now both the bones of the mastodon and some surrounding charcoal have been dated to around 13,800 years ago, around 600 years earlier than the first Clovis sites in the northwest.
Which is very interesting. But I still don't understand what these early dates are supposed to mean. Whoever else was living in the Americas when Clovis culture emerged, about 13,300 years ago, they immediately disappeared. Clovis spread across North America in a century, became the dominant culture everywhere (which is hard to imagine if the continent was already full of people) and then spawned an offshoot that spread across South American to Tierra del Feugo in a few more centuries. Everywhere Clovis people went, animals went extinct. And so, it seems, did any people who were here before them, since all the genetic studies show that Native Americans are descended from a single small founder population.
If there were people here before Clovis, they seem to have had about as much impact on North American history as the Vikings.
I don't want to sound certain about any of this; it was a long time ago, and we don't know very much about what was happening. But I wish people would think about the implications of their data instead of just getting excited about old radiocarbon dates. If there were people in North America for hundreds or thousands of years before Clovis, what happened to them, and why did they leave so little evidence of themselves?