The rock, serpentine, was named in the 16th century by geologists who thought its dappled colourings resembled snake’s skin.

Serpentine with an old quarryman’s initial to show who’d taken out the rock

The 20 square mile outcrop of the attractive rock which is centred at the end of the Lizard is unique in the UK. Originally formed deep in the Earth’s crust it has, over millions of years, been subjected to enormous pressures and high temperatures and the resultant differences in mineral content produce a rich, multicoloured veining.

For the best part of 200 years local craftsmen have been quarrying and working the stone, and their small huts and workshops can still be seen at the end of the peninsula today.

Nowadays only a few people are licensed to extract extremely limited amounts of the rock. It was not always so – in the mid-1800s there was quite an industry at work quarrying and working serpentine, and by 1883 20 men and three boys were being employed by the Poltesco Marble Company.

Cheap marble imports, the Lizard’s remoteness and the serpentine’s weakness to deteriorate quickly in polluted exterior situations all helped to secure the industry’s demise.

But the local families worked on and still produce all manner of gifts fashioned out of serpentine today - perhaps best known are the neatly turned lighthouses that by now must adorn a million mantelpieces around the world.

A while ago I visited a corner of the Lizard Peninsula to find out more…

If you were to devise a recipe for the perfect secret seaside it might go something like this: take a remote coastline far from the madding crowd and punctuate it with a beautiful wooded valley featuring the long lost remains of old water-mills and have its burbling stream issue out on to a lovely, lonely, beach - pausing just a while to form a pond under some mysterious looking ruins.

That is almost an exact description of the Poltesco Valley leading down to Carleon Cove, way down on the Lizard Peninsula’s south eastern coast – inaccurate only in that it is not very far from a madding crowd…

The exquisite fishing village of Cadgwith has always been popular with tourists – and has been especially so since Monty Hall based his excellent Fisherman’s Apprentice TV programme there recently. But Carleon Cove – which is the small indention just two bays north of Cadgwith – may as well be 100 miles from a tourist honey-pot.

When I adventured there on the hottest day of the year so far recently, just one family was sitting on its pebble beach.

The Western Morning News was invited to visit the Poltesco Valley and its magical hidden cove by Justin Whitehouse who is the National Trust’s head ranger on the Lizard – and before we began our walk down to the shore he explained how an old farm in the coombe now acts has his local base.

“We’ve got workshops here, an education room and my office which is in a shepherds hut. This was a farmstead and 100 years ago and would have been a thriving place. The river has one of the largest falls of water to run off the downs, so in the days of waterpower it was a busy industrial valley - there were about five or six mills altogether.

“There was a mediaeval mill just here, probably dating from the 1300s - but the one further up was working until the last century. However, the main industry happened further down the valley – and that was to do with the serpentine industry in the 1800s.”

With that we began our walk down one of the paths which the trust has introduced to the valley and I asked Justin if short and pleasant stroll taken by many people…

“Carleon Cove is gorgeous, but it is relatively quiet. Maybe that’s because it’s a boulder cove - but it is a secret spot and not many people know about it. I suppose you could call it a locals’ beach. From my point of view there’s much more to do here than on a bucket-and-spade beach,” he added, referring to popular Kennack Sands which is the next seaside spot to the north.

“There are fantastic rockpools at low tide and just exploring the ruins here is fascinating - there’s masses of history. I bring my children here and they absolutely love it. There’s the river, you can swim off the rocks - and also it’s pretty calm usually being on the eastern side of the Lizard.

“The people who do take the trouble to walk less than half a mile to discover this place enjoy a sense of ownership - they really think they have discovered it, which I think is good.

“There are lots of secret seasides or coves on my patch,” he went on. “In fact, there are some I probably wouldn’t tell you about - because it’s all about exploration. Getting out of your cars, packing a day-sack and going for a walk… You can’t go wrong - keep the sea on one side as you walk and you will come across gorgeous little coves just like this.

“There are people who just want to drive somewhere, but that adds to the magic of this place – you can’t drive to the cove. And not everyone wants to make the effort to come to a beach like this, but I would encourage anybody to get out of their car and find somewhere like this. There are some hidden coves that are a bit of a scramble,” added Justin with a warning. “And I would remind people to be careful.”

Carleon Cove might be a place where gulls go to be lonely today, but it wasn’t always like that – as you can tell from the jumble ruins which stretch off into the bamboos and trees at the back end of the beach.

Almost all of these were connected to the old serpentine industry which flourished here for just a few decades in the 1800s, but adjacent to the one intact building which remains there’s a clue that point to what people did in Carleon Cove for many centuries before the weird rock was discovered.

It’s the exterior wall of an ancient winch-house, similar but smaller to the one you can still see at Sennen Cove – and it would have been used to haul up the heavy wooden boats by the fishing community that once plied their trade here.

You can imagine the surprise those old fishermen had when – over a very short period of time – they saw their peaceful cove overtaken by a frenzy of extremely noisy and dusty hacking, hewing, sawing and chiselling…

Justin explained: “Legend has it that back in the 1860s Queen Victoria and Prince Albert were sailing around the Lizard when Albert felt a bit seasick - so they came ashore at Kynance Cove and Albert bought a piece of turned serpentine. And he got a taste for it…”

For those who don’t know it, serpentine is metamorphic rock laced with dark green veins and dotted here and there with reds and whites. Not only is it attractive, but it is easily worked and the story goes that Prince Albert bought an armful of small items from the one or two craftsmen he came across near Kynance, just a few miles away from the Poltesco Valley on the west coast.

“At the time there was just a small industry going on,” said Justin. “But suddenly it had royal approval and everybody wanted serpentine. As a result this factory sprouted up here. It was open for about 40 years and it was churning out everything from chimney pots, coffee tables, fireplaces, church fonts - big things, not just the small knick knacks.

“The quarrying took place a bit further down the coast,” he explained. “But the factory was here because of the fall of water and they had a waterwheel to power the heavy machinery. There would have been big stone cutting equipment, because there were huge boulders moved here - strung above the river on aerial launders. They’d have cut them, shaped them, polished them… And, believe it or not, flat bottomed stone barges would have come in from the sea and moored up here in the little river where the pond now is.

“Large schooners would have moored offshore out in the bay and the barges would have taken stuff out to them and they’d have gone off to London and the Continent. We know for sure there were 20 men working here in the factory - so it was a big industry for the area.”

So why did it all disappear?

“Well, again this is according to legend… But the story goes that Queen Victoria went on holiday to Italy one year and discovered marble - and suddenly it was in vogue - nobody wanted this old fashioned serpentine any more. It’s probably a good job that happened - if it had carried on this place could now be a huge industrial site.

“In fact, The Trust only acquired this valley in the 1970s and I’ve heard that the pervious owner deliberately demolished some of the buildings here because he was adamant he wanted to protect the place and let nature take over.”

Having said that Justin cast his gaze across the ruins down by the beach and said: “This all looks a bit wild, but it’s not just left - there’s sensitive management going on here. It is a haven for wonderful stuff, including rare plants and animals. For example, there’s Babbington’s leek – a plant that was first discovered in the Poltesco Valley – in fact, it was one of the last plants to be named and identified in the last century. The Reverend Babbington came here and discovered this gorgeous form of architectural onion.

“And the places is an absolute haven for reptiles - it is riddled with lizards and adders the river has frogs and toads. And no, the lizards didn’t give the peninsula the name - Lizard is a corruption of old Cornish for high place... You can imagine it would have been quite dramatic as you were approaching the mainland in an old ship and you saw this high place.

“The Trust owns a total of 22 kilometres of coastline on the Lizard today,” Justin told me. “I suppose it’s most famous for the Cornish chough – and it’s been a good year for them. We’ve now had 11 years of successful breeding and most of that is to do with habitat - we have worked with our tenants and Natural England and brought the habitat the choughs need back.”

Poltesco Valley, however, is not an example of the open coastal heath so beloved by Cornwall’s “national” bird. “This valley is unique - it’s one of the very few wooded valleys around here - we even have elms. This is one of the best stands of natural elms left. They do get the dreaded Dutch elm disease but the Cornish elms here are a little bit more resistant. And the geographic position means they are a more isolated population so there is not the concentration of the beetle that causes the disease.”

As we sat there on the rocky beach joking about the modern journalistic obsession in Britain for “silly-summer-period” stories about great white sharks (a possible sighting of one was made just off the Lizard a few months ago) Justin fell into the kind of reverie people occasionally have when they work in very beautiful places…

“Most of all this a brilliant place to explore - all the local schools come to our education room and within 500 metres they have the beach, rock-pools, woodlands, the river, the history, the heathlands… Poltesco Valley and its beach has got absolutely everything all in one small area.”