It's 6,000 normally, as they have never heard of fossils.
Anywho, I have something to post in here, it's about a guy beating on some kid and getting away with it, I can't for the life of me find the link to it, though, and that alone is making me RAGE.
Actually, the method they use to find out the age of the fossils is by the layer of Earth its found in. And guess how they decide which age each layer declares what's found in it? By the fossils in them...