In the 1980s, archaeologists from the Florida Museum of Natural History opened a formal excavation in one particular sink. Below a layer of undisturbed sediment they found nine stone flakes that a person must have chipped from a larger stone, most likely to make tools and projectile points. They also found a mastodon tusk, scarred by circular cut marks from a knife. The tusk was 14,500 years old.
The age was surprising, even shocking, for it suddenly made the Aucilla sinkhole one of the earliest places in the Americas to betray the presence of human beings. Curiously, though, scholars largely ignored the discoveries of the Aucilla River Prehistory Project, instead clinging to the conviction that America’s earliest settlers arrived more recently, some 13,500 years ago. But now the sinkhole is getting a fresh look, along with several other provocative archaeological sites that show evidence of an earlier human presence in the Americas. Around 135,000 years ago, sea levels were lower and what is now Siberia and Alaska were connected by a land bridge. That offered an easy route for bison and perhaps wooly mammoths to migrate from Asia to North America. Early humans easily could have followed, whether those “humans” were Homo sapiens, Homo erectus, Neanderthals, or little-understood Denisovans. But even if they were a different species, they were likely similar to modern humans, capable of verbal communication and with the knowledge of various survival skills. Does this solve your question?
The 'oxbow' lakes take a U-shape form when a river meanders. At some point, it grows bigger and gets loopy so the two bends of the river join together.
