[Coyoteman]

Louis Leakey (the old, dead guy) caught hell for talking about greater antiquity than the (at that time) dogma of 3000 years (IOW, the blind belief back then was that humans had entered the Americas no more than 3000 years ago). This was before Clovis entered the picture. He based that on the number of major civs found around the two continents, the number of language families, etc. Since that time, Clovis-First-and-Only replaced the 3000 year limit.

You might want to research this one a little more. I think the western US had radiocarbon dates far older than 3,000 years at the time Leakey made his pronouncements.

[SunkenCiv]

Perhaps you're right, but I don't think so. Radiocarbon dating (that began post WWII) is what got Clovis dates accepted; Leakey's visit was circa 1930.