[Diogenesis]

They were hardly the first.

The Pilgrims landed and fortunately found Squanto
of the Wampanoags, who had already
traveled across the Atlantic TWICE to their once,
and who taught them to plant corn with fish,
and other technologies,
... without which they would have died.

[RJS1950]

I also strongly believe that the east coast tribes were largely descended from the peoples of the Solutrean migration.