“I can see the probability of the Indians native to south of the Rio Grande making it to what is now California, but they were not Mexican in any sense of the word.”
The people’s of the geographic region of what modern day people have drawn lines on a map calling it Mexico referred to themselves in their native Nahuatl word as MÃÂxihco. Thus the Spaniards called them Mexicans. Those people’s native language goes back thousands of years probably as this study shows 5000+ years. People have been in north,meso and South America for at least 20,000 years there is evidence in Central Texas of 30,000 year old anatomically modern humans. The DNA evidence is showing multiple waves of migration over the last 20,000+ years from vastly different DNA groups. Most modern First Nations, Eskimo, and PacNW indigenous share a common ancestor in the Siberian region.
Kennewick Man who is 9000+ years old has completely different Y chromosome groups and his closest ancestor is from the occupied japanese island of Hokkaido with the indigenous Ainu all having this Y chromosome group. Some PacNW tribes have Kennewick Man Y as do a good number of plains American Indians, every living Comanche has this Y group as does the one typing this post I am 40% by DNA Comanche/Apache. This shows at least two groups came in two waves in the past.
The current theory is one came over the land bridge the other used boats and island hopped following the rich marine life that always exists at the edge of the sea ice. The Eskimo still to this day live this lifestyle. Humans have been able to make ocean going boats for at least 50000 years there is evidence in Australia and the.Mediterranean for long distance 200+ mile round trip Stone age boat trips.
Obsedian from a single 100+ mile offshore source in the med has been found in Neanderthal sites dating past 50000 years closer to 100,000 all over the med. This alone confirms seafaring tech in the Stone age rafts couldn’t make the trip and swimming is right out.
People have built modern copies of kayaks using primitive materials ,skins and tools then paddled them from North America to the UK and Europe. Same for Irish skin boats one explorer made a primitive era ocean going skin boat and sailed it from Ireland to New York.
The DNA shows that South American indigenous have at least two sources one of them is Polynesian in Y chromosome groups. The Polynesians absolutely being master mariners could have reached South America. South American could also have reached Polynesian islands the Kon Tiki is the actual proof of this that balsa raft sailed from Peru to deep in Polynesian territory. The fact that yams are in the Polynesian islands shows someone took them there thousands of years ago they are indigenous to South America.
The point is humans including our sub species of Neanderthals, sapiens and modern sapiens sapiens all had ocean going boat technology and used that for very long-distance travel. Australia was populated 45000 years ago requiring a 200+ mile open ocean crossing. To think that 20,000 years later humans couldn’t travel along the coast line from Asia to North America them down the coasts to Mesoamerica and South America is simply absurd. Humans also could and likely and travel from Europe to North America thousands of years ago. It’s proven Vikings made it in 1000AD there is DNA evidence and preclovis Stone tech that shows Iberian Peninsula humans got to North America 25000+ years ago before the Siberian region Y chromosome groups 12000 years ago, and the following 9000yo Hokkaido Kennewick Man tribes.
There are deep scouring marks on the floor of the Med just inside Gibralter....this supports the theory that the Med was 'plugged' at Gibralter during the Ice Age and the Med nearly dried out.
When the 'plug' broke a monumental waterfall occurred at Gibraltar and slowly filled the med and eventually crashed through the barriers at the Bosporus flooding (Noah's Flood) that fresh water lake (Black Sea) about 7,600 years ago.
There was a time when people lived on the floor of the Med. and wandered around it for hundreds of miles.
When the Black Sea began to flood, the water rose about one foot per day...people were able to safetly walk away and I expect something similar when the Med refilled...walkaways.
The refugees from the Black Sea flood fled up the river valleys into Europe and took farming and their Indo-European languages with them.
BTW, the Med did completely dry out at least once but it was five million years ago.