The initial peopling of the Americas, when, by whom, and how, has been controversial (to put it mildly) for many years, starting back in the 1920s with the discovery of the first association of human artifacts, Folsom points, with extinct Pleistocene bison, at Folsom, NM. The notion that Clovis has a European origin is a minority opinion in an area of research that is rife with dissenting concepts and theories. There is mounting evidence, including DNA work, that Clovis was not the first and that the first humans probably entered North America through the Bering land bridge. Wikipedia has a good summary that doesn't take sides: http://en.wikipedia.org/wiki/Clovis_culture