I found this information the Finnish/Native American connection.
Facinating topic. Finnish is one of the languages JRR Tolkien studied as a philologist. He studied ancient languages and gleaned history out of the meanings held within the words. He "created" the elvish languages of Quenya and Sindarin mainly based on Finnish. He also had something to say about Native Americans but I can't seem to find it (I have probably 1,000 pages of writings on these topics so it would be hard to find!).
Anyways, Native Americans (Indians) did not all come across a land bridge from Siberia to Alaska. Many migrated across the Atlantic from Europe and the mid-east. Many of the tribe of Joseph came to North America. Egyptians also, as well as some northern Europeans.... way way way before Leif Erikson. Try 500 to 700 BC. Even earlier.