Country diary: a vertical timeline is clearly visible in the cliffs

Walton on the Naze, Essex The iron-rich, sandy layer of the Red Crag, laid down by a cool sea, is rich in marine fossils.

I walk past the arcades and beach cafes. The smell of vinegar on chips is sharp in my nose and makes my mouth water but I haven't come to Walton on the Naze for seaside snacks. Higher ground is visible beyond the beach, partly shrouded in mist, and I strike out towards it.