In considering the development of American prehistory, it is important to remember that man reached the New World very late in his evolutionary career. Paleontologists have uncovered many human fossils of great age, quite different from modern man in physical form - such as Pithecantrhopus erectus, the "ape-man" of Java; or Homo neanderthalensis, "Neanderthal man," the round-chinned, big-headed man of Ice Age Europe. From this fossil evidence they conclude that man emerged more than a million years ago, probably in Africa but perhaps in Southeast Asia, and that at least one human stock came throught a series of evolutionary changes to assume more or less the present human form less than one hundred thousand years ago.
But there were no human beings at all in the Western Hemisphere during this evolutionary period. At least, no fossils of really primitive human forms have ever been discovered here. Pithecanthropus, Neanderthal man, and the other extinct human types never set foot in the New World. There were not even any manlike apes here, it seems; gorillas, chimpanzees, and other higher primates are strictly Old World natives. So far as the fossil record shows, the whole story of human evolution took place overseas, and when man got to the Western Hemisphere he was basically in his modern form.