no circle here is no circle here is

http://www.foxnews.com/story/0,2933,200701,00.html
The shells from Skhul were excavated in the 1930s. The researchers were able to date them by comparing sediment stuck to one of them with layers containing human skeletons that were 100,000 or more years old.
By the way, the sediment on this particular dig is dated by the bones in them. They know the date of the bones because of the layer they are buried in. So now we have a third layer of dating. Have I mentioned lately how great carbon dating is?