Mounting evidence that Europeans in America predated the arrival of Native Americans.
When the crew of the Virginia scallop trawler Cinmar hauled a mastodon tusk onto the deck in 1970, another oddity dropped out of the net: a dark, tapered stone blade, nearly eight inches long and still sharp.
Forty years later, this rediscovered prehistoric slasher has reopened debate on a radical theory about who the first Americans were and when they got here.
Archaeologists have long held that North America remained unpopulated until about 15,000 years ago, when Siberian people walked or boated into Alaska and then moved down the West Coast.
But the mastodon relic found near the mouth of the Chesapeake Bay turned out to be 22,000 years old, suggesting that the blade was just as ancient.
Whoever fashioned that blade was not supposed to be here.
Its makers probably paddled from Europe and arrived in America thousands of years ahead of the western migration, making them the first Americans, argues Smithsonian Institution anthropologist Dennis Stanford.