I don't understand why some of the pre-Clovis people couldn't have come from Europe. If the Phoenicians went as far as England in search of tin, couldn't seafaring people from the British Isles and/or Scandinavia have ventured westward to North America? It seems to be it would be a lot easier to get to Ohio from the east coast than the west, especially if glaciers covered much of what we now know as the Rocky Mountains.
Fascinating stuff!
I agree. If, as Greenfield says, people populated North America from the southwest to the northeast, why are some of the EARLIEST sites found around the Atlantic seaboard, such as
Cactus Hill in Virginia,
Meadowcroft Rockshelter in Pennsylvania, and
Topper, South Carolina?
The first peoples in the Americas were Europeans who arrived over 19,000 years ago, were hunting seals and auks along the permanent ice sheet that covered a much reduced in size Atlantic ocean. They arrived to now drowned lands at the Grand Banks off Newfoundland and moved southeastward, probably follwing sea birds back to the main land.