Jenni Mills

Look at this. A sea urchin, so close we could snog each other. My eyes are crossing with the excitement, not to mention the proximity. I feel like calling to Martin to get his fat arse down here, so I’d have someone to share it. But Martin couldn’t care less, and neither could the sea urchin.

I’d guess it’s been dead for a hundred million years or so. When it was pottering about, doing whatever sea urchins do in the warm shallow sea, dinosaurs tramped the shore. It looks like a bun, doughy white, slightly heart-shaped. The stuff of life, turned to stone.

I’m lying on my back. Stone is digging painfully into bone, nodules of chalk and outcrops of flint, none of them dovetailing with the knobbles on my spine. My nose is a couple of inches away from a white chalky ceiling with the sea urchin in it. Until I saw it, I was trying to turn over, to wriggle back the way I came in — feet first, because there isn’t room to turn round. This is a fairly delicate moment. I don’t think the entire lot is going to come crashing down on me, but it’s always possible. The tunnel’s hardly more than body width. Even by Neolithic standards, this is poky.