It's because we know when each of these species became extinct that these fossils are helping us to date the site.

This is a tooth of, um, a mammoth.

And this is, in fact, one of the earliest forms of mammoth, uh, that we find in this part of the world.

This helps us with the date because this is quite primitive.

So we have a fantastic record-

And you can, you can tell that from the teeth?

That's right, yeah.

It has very distinctive teeth.

There are

hyenas, so you've got large carnivores.

We've got this fantastic rodent, jaw, with some of the teeth.

And this is an extinct beaver-like rodent, and it was semi-aquatic, living along the banks of the river.

the teeth?

That's right, yeah.

It has very distinctive teeth.

You can see this is the chewing surface.