The immigrants, which supposedly walked thousands of miles across a frozen waste linking Asia and America, were probably not this continent's only early arrivals, nor were they, apparently, even the first.
It has long been conventional wisdom that the first Americans came here across a land bridge to Alaska. We are to accept that they were actually just following migrating herds of animals, when they suddenly found themselves in Seattle.
Those animal-skin clad, club-wielding savages then, supposedly, spread out to cover all of the Americas, from Canada, to the bottom of South America. I submit that to be seriously flawed conjecture.
Puzzling bits of evidence make intelligent persons wonder about that simplistic theory. Why is it, for example, that those immigrants, which most likely are the ones that settled in western parts of Canada and the U.S., had no written language, no knowledge of science (by whatever name), built no substantial nor important structures, and were organized, if at all, into primitive and unproductive groups; yet soon after one crosses the Mexican border heading south, there is overwhelming evidence that the "Indians" which settled there were light years ahead of those up in Montana and New Mexico.
Those southern "tribes" studied medicine, astronomy, architecture, and agriculture; they built awesome pyramids and other magnificent structures that survive to this day; they organized themselves into effective city-states, complete with laws, religion, military forces, and even social welfare.
Do you really believe that they are only an extension of the northern Indians, whom were still living in modified "caves," or other primitive shelters when first seen by much-later, Caucasian immigrants?
If one looks at a map showing the locations of Indian settlements in Central and South Americas, it can be clearly noted that they are closely grouped and centered along the western coasts, suggesting strongly that those particular immigrants arrived by sea. And the fact that some Mongoloids (i.e., "Asians") had developed the skills needed to build large sailing ships, along with the ability to navigate them across vast stretches of the Pacific Ocean indicates that it was quite possible for them to have reached places such as Peru, where recent findings seem to predate anything found in North America. That people's advanced culture (particularly celestial navigation) would also explain why their great and enduring cities often featured celestial observatories.
Yes, there is compelling reason to believe that the southern parts of the American continent were inhabited by man before he crossed that well-known land bridge to Alaska, and that the southerners were a significantly different people. But the challenges to the validity, or accuracy, of the northwest land-bridge theory don't end there.
Relatively recent archaeological findings in our own Northeast have led experts to conclude that man was living there before he arrived from the Northwest. Perhaps there once was a northeastern land bridge, or possibly those earlier immigrants made part of their trip in boats.
Could it be that the Indians inhabiting eastern U.S. were, like those in southern America, a distinctly separate ethnic group from those that followed herd animals across Alaska?
Then there's the fact that most of the Indian archaeological sites in eastern Mexico and Central America are found on the coasts, which, again strongly suggests arrival by sea, rather than across land.
Look at Mexico's Yucatan, where it's greatest early-day cities are located, and you'll see that it is a peninsula, with long coast lines, making access to the sea easy. Did those Indians (Mongoloids) arrive there from northern Europe? If not, from where? The clearly didn't migrate down from North America, because, once again, they were a significantly different sort of people.
Finally, one of the more fascinating parts of this puzzle (about just whom the first immigrants were, and from whence they came) involves one of the early settlements on the Yucatan (near Villahermosa). It was there where the Olmec people settled, and created monumental stone sculptures of human heads, which today strongly suggest that they might have been of the Negroid race.
Since the region is on a coast accessible to boats having crossed the Atlantic, it is possible that Negroes actually arrived there at or before the time when so-called "Native Americans" crossed that well-known land bridge in the Northwest.
Professional scholars and historians will likely challenge some of my conclusions and questions, but I expect none will attempt to explain how and why, if all "Native Americans" came across that Alaskan land bridge, the early peoples of South and Central America were so significantly different from those to the north? I think that our version of the origins of man in America needs major revision. But would that be politically correct?