(this refers to the finds in Cuba and around)
They are not proven or unproven, the road was a bit of no go - at a way to large of scale to be anything.
This time coincides with the introduction of people in the New World and colonizing virtually every region of it. Consequently, evidence for human occupation sites, particularly sites left by colonizing fluted point bearing people, is expected on the continental shelves. The map shown to the right is a compilation of the distributions of fluted points across the United States. It reveals several areas of concentration that may have components submerged offshore.
Some 20,000 years ago, for example, ice sheets locked up much of the world’s water, lowering the oceans and laying bare vast coastal plains—attractive hunting grounds and harbors for maritime people. Today these plains lie beneath almost 400 feet of water, out of reach of all but a handful of underwater archaeologists. “So this shines a spotlight on a huge area of ignorance: what people were doing when sea level was lower than at present,” says Geoff Bailey, a coastal archaeologist at the University of York in England. “And that is especially problematic, given that sea level was low for most of prehistory.”
The underwater structure will not have changed that much during that short geological time.