Of course this could turn out to be another fail, if humans were seeded in the Americas by space aliens...

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PALEOLITHIC TRUTH BOMBS —
Time to scrap the idea that humans arrived in the Americas by land bridge
Bering Land Bridge fossils show a lifeless area until long after humans hit the Americas.
Annalee Newitz - 8/11/2016

The standard story of how humans arrived in the Americas is that they marched 1,500km across the Bering Land Bridge, a now-vanished landmass between Siberia and Northern Canada that emerged roughly 15,000 years ago in the wake of the last ice age. But for the past decade, evidence has been piling up that humans arrived in the Americas by traveling in boats along the Pacific coast. Some 14,000-year-old campsites like Oregon's Paisley Caves have been found near rivers that meet the Pacific, suggesting that early humans came inland from the coast along these waterways. Now, a new study published in Nature provides more solid evidence the first humans to reach the Americas could not have come via the Bering Land Bridge.

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http://arstechnica.com/science/2016/08/time-to-scrap-the-idea-that-humans-arrived-in-the-americas-by-land-bridge/