I'm not so sure. He thinks the artifacts at Calico were man-made.
Calico: A 200,000 Year Old Site In America
"(1) the authenticity of the artifacts; are they truly the product of human manufacture, or merely naturally produced "geofacts?" and (2) the obvious pre-Clovis age of the deposits (see, for example, lengthy discussions in Leakey and others, 1968; Haynes, 1973; Bryan, 1978; Taylor and Payen, 1975; Carter, 1980; Meighen, 1983; Patterson, 1983; and Budinger and Simpson, 1985)."