Trawling for fresh business

You can only reach Penny Steel and Jet Wyke at low tide but at the very edge of these flat rock scars east of Staithes you are standing on the remotest point of Yorkshire's North Sea coast. Here, you can watch the sun rise and set in the same sea, and today you can see from Wearside to Whitby.

More pressingly, our party of seven are craning our necks at a dangerously unstable chimney of rock called Old Nab that looks ready to topple down on top of us at any moment. Listen carefully and you can hear the trickle of falling shale. These cliffs are on the move.

We are on a shoreline walk from the old sea-smugglers' village of Staithes to the lost harbour of Port Mulgrave with our guide, Sean Baxter. It's part of an eye-opening seashore discovery day that takes in fishing, foraging, wildlife, industrial archaeology and geology – all to be found within a dramatic two-mile stretch of seashore.

It is one of those heart-lifting early summer days when a dull sky suddenly turns blue, and the retreating tide leaves behind crystal clear pools teeming with life: winkles, sea anemones, hermit crabs, the silver flash of a sprat and a tiny white flatfish none of us have ever seen before. "Turbot," says Sean instantly.

When he is not taking out fishing and bird watching parties on his fishing boat All My Sons, or teaching fishing skills in Sierra Leone or Papua New Guinea, Sean is guiding groups like ours along the foreshore on his one-day and three-day residential discovery days he calls 'Real Staithes'. If farmers have learned to diversify, so it seems must fishermen.

"I'm no expert," says Sean, "just an enthusiastic amateur". He sells himself short. He has lived and fished this coast since he was a lad. He was helmsman on the Staithes and Runswick lifeboat for 20 years, plucking his fair share of stranded walkers from these very cliffs. His wife Tricia was born and has lived all her life in Staithes. Between them they know the place inside out.

"We want to extend the story of Staithes beyond the pub and the beach," says Sean. "We want people to understand the sea. When they understand it they will respect and enjoy it. We want to give them a holistic view of Staithes.".

We've already been out for an hour, peering into rock pools, pulling up longlines, seeing how black sea slugs emit a bright purple dye when you pick them up. We make slow progress, but that's the point. What looks like a slice of virgin seashore gradually reveals itself as full of historic human fingerprints.

That unsteady lump of rock at Old Nab came about through ironstone mining back in the 19th century. Sean points out the seams of ironstone still visible in the cliff and the ruts cut into the foreshore that are remnants of old waggonways used to transport materials up and down the shore. A channel dynamited through the rock floor let sailing ships approach to collect the ore. There are strange tanks cut into the scar where lobstermen once stored their live catch. More holes mark the line of a long lost jetty.

Before ironstone there was alum – used to fix the colour of dyes – and the demand for alum gouged great bites out of the cliffs along this stretch, most spectacularly just west of Staithes where the moonscape of Boulby Cliff rises 666ft out of the sea. They're still mining here today. Boulby Mine, the deepest in Europe, hauls out a million tons of potash fertiliser and road salt every year.

Yet another industry was jet, the fossilised remains of prehistoric monkey puzzle trees. It's still here if you know how to find it. Sean does. "Chalk it on a piece of sandstone. If it's brown, it's jet; if it's black, it's coal."

We find plenty of coal but the jet we eventually take home has to be chiselled out of a thin seam, deep in the cliff, much as the Victorian jet miners would have done. Except that they worked from the terrifying 'dresses' we can see high up on the cliff. "They lowered children down on ropes to hammer in the stakes," says Sean. One rope still dangles, a very scary escape route for anyone cut off by the tide.

Beneath our feet now is a remarkable fossil bed, packed with bullet shaped belemnites, spiralling ammonites, beautiful clam shells and fossilised tree roots from when this was a prehistoric tropical lagoon. World class ichthyosaurs and plesiosaurs have been unearthed along this coast making it one of the most important geological sites in Britain – the Jurassic Coast.

Less epic but still amazing, Sean picks up a weathered yellow firebrick engraved with 'V & D', identifying it as part of the cargo of the SS Clementine which foundered off Staithes in 1924. The sea has been tirelessly tossing up the bricks ever since.

Having set fishing lines that fail to catch anything big enough to eat –on a good day you might land cod or whiting – we snack on 'kelp crisps', broad strands of seaweed that Sean has oven-dried into salty, black, iodine-infused seashore snacks. An interesting taste, but possibly not a commercial one.

And then suddenly we turn a corner to discover Port Mulgrave harbour, not quite a secret port but there is no road to it, no electricity, no residents and since its railway tunnel was bricked up, it is only accessible by boat or on foot. Created in 1857 to ship out the local ironstone by sea, 800 ships a year once used it. That heyday is unimaginable now. The harbour is silted up and only a ramshackle collection of fishermen's huts remain. But those huts are a beachcomber's dream, cobbled together from cast-off doors, disused fishing cobles, lumps of driftwood, railway sleepers and the flotsam and jetsam of the seashore. Naturally, Sean has one, a black corrugated iron shack with a bunk inside and the luxury of a veranda.

On it a vat of soup is simmering.

A sturdy smoke blackened kettle steams over a campfire and like a scene from Little House on the Prairie, Tricia greets us at the doorway in her apron.

Our lunch, based around a bowl of velvet crabs and half a dozen scarlet lobsters from Sean's own pots, supplemented by Tricia's soup, salads, bread and minted new potatoes, could scarcely taste fresher or better.

And, making it taste even better, there's not a restaurant in London that will serve you a whole lobster for under 30.

It's a stiff climb up the cliff after lunch, but an easy stroll along the Cleveland Way back to Staithes.

Far down below, Port Mulgrave is soon invisible, the incoming tide is fast covering our route, hiding all its surprising history.

It's been an exhilarating day of sea and shore, of big skies and birds – oystercatchers lunching on mussel beds, a cormorant on a low level mission across the water, a kestrel hovering above the cliff.

On another day there might be seals and peregrine falcons or a show-stopping fossil unearthed by the next cliff fall.

Until then I can put my hand in my pocket and touch 160 million years of Yorkshire history with my modest belemnite, my coiled ammonite and my genuine chip of Whitby jet.

Real Staithes, day courses 50. (Next day course, August 6). Three-day residential course, 245. Contact Sean Baxter, White House, Church Street, Staithes, TS13 5DB. 01947 840278

Edible Seashore by John Wright, River Cottage Handbook No 5, Bloomsbury 2009, 14.99. To order a copy from the Yorkshire Post Bookshop, call free on 0800 0153232 or go online at www. P&P is 2.75.