Humans in N America during the Ice Age?

It's all starting to spill out as the Clovis theory takes another stumble. A Canadian scientist analysed animal remains found in Ohio and claims a leg bone of an extinct giant ground sloth had been butchered – one of those notoriously difficult kind o interpretations that we might expect to have some kickback in the future – see http://archaeologynewsnetwork.blogspot.com/2012/03/butchered-sloth-bone-…. Cut marks on the bones have been analysed and it seems they represent human action. On that basis, as the bone was found in Ohio, this is taken to prove a human presence there in the period prior to Clovis. In fact, a wave of Ice Age migrants from Siberia, it is thought.