Slowly, Slowly

For decades, archeologists and anthropologists specializing in North America has a very firm timetable for when and where humans spread across the continent. Anything which showed that people were actually here earlier were dismissed as "flukes" due to "misinterpretation" or "contamination."

Except that the flukes are piling up. Now there's genetic evidence showing that people didn't wait for the ice to melt but either walked along it or used boats.

Archeology is, for some very good reasons, very conservative. But it is a science, and science is self-adjusting.