Henry Gee

So the underneath of the trilobites, you can see the gills that are attached to the legs, very much like crustaceans.

They weren't particularly closely related to crustaceans like woodlice.

Woodlice are crustaceans.

They were the kind of their own thing.

There's a lot of debate about which jointed-limbed animals they were most closely related to, but they kind of exemplify that kind of spiny, leggy creature with a skeleton that they could shed with big eyes.

They're even fossils now of the internal digestion of trilobites showing what they ate.

They kind of snarled up things and digested them.

they don't really have a mouth with jaws crustaceans they do have a mouth but it's surrounded by all kinds of mouth parts and they just stuff stuff in and grind it up they were great because you know what like one of my favorite fossils lystrosaurus which was a go anywhere eat anything fossil from the triassic trilobites were a bit like that only in the cambrian which may have been why they were so successful

Well, the Cambrian is named after Cambrian whales, so that's full of Cambrian hornets, but there was a lot more to the Cambrian than trilobites.

A century ago or so, there was a fellow called Walcott who was a geologist, and he used to take his family on vacation to British Columbia.

And high up on a mountain in British Columbia, he and his family discovered what are now known as the Burgess Shales, which are actually a series of quite small exposures

Very high up.

I mean, I've not been there.

There was a field trip I didn't go on because I knew I was not going to be fit enough to get there.

I mean, it's like mountaineering to get there.

We're high up in the Rockies.

It just shows you the power of the earth.

There are these deposits that happened in the deep sea 508 million years ago, something like that.

So picture the scene, continental shelf, a mudslide, berries, all these animals all at once, and they go down to the deep sea.

And because of not very much oxygen, they're preserved perfectly, including their soft parts.