Ronald Turnbull uncovers the varied geology of the Scottish seashore, and explains why Scotland’s coast is uniquely fascinating from the shell beaches of the Hebrides to the twisted grey cliffs of Galloway and the red seastacks of Dunbar, from the mudflats and saltmarsh of the Solway to the basalt caves of Mull.

Most of us love the seaside and Scotland’s wildly indented coast abounds in possibilities. A Handbook of Scotland’s Coasts is intended to feed your natural delight in getting to the coast. It is a sharing of enthusiasm for places to explore and things you might do once you leave your car or bike and get right down to the shore. So there are suggestions for great days out and discovering the many activities on offer around Scotland’s coasts.

Each chapter in the book is written by someone who really knows and loves his or her subject. Leading Scottish nature writer Jim Crumley considers coastal wildlife whilst historian Michael Kerrigan takes us on a marvellously eclectic tour of our coastal culture. Hebridean sailor and poet Ian Stephen takes us around Scotland’s many islands, and Fi Martynoga explores coastal flora and fauna and foraging possibilities. Ronald Turnbull uncovers the geology of our seashore, and here he explains why Scotland’s coast is uniquely fascinating:

“Scotland small?” asks Hugh MacDiarmid – the words are carved in beach granite from Caithness in the wall of the Scottish Parliament. And his poem of 1974 describes the variety of life in one small patch of heather. How much less small, then, when you take the whole of Scotland’s coastline: 6,718km, according to the Ordnance Survey, for the mainland alone, and three times that if you add in all the islands.

From the shell beaches of the Hebrides to the twisted grey cliffs of Galloway and the red seastacks of Dunbar, from the mudflats and saltmarsh of the Solway to the basalt caves of Mull, Scotland has almost every kind of coastal formation there is; from almost every age of the earth, halfway back to when the planet cooled enough to congeal into continents. And with the wandering of those continents, Scotland’s cliffs and boulders come from the southern oceans, and unknown places even earlier.

Understanding of it starts at a scrap of sea cliff called Siccar Point, just south of Cove Harbour on the Berwickshire coast. In 1788, at the full flowering of the Edinburgh Enlightenment, James Hutton and John Playfair came ashore here from a small boat. And what they saw, embedded in the coastline of today, was a scrap of coastline from 360 million years ago.

The rock here is the harsh, layered greywacke – a dark, grainy type of sandstone – of the Southern
Uplands, tilted up on edge by some
cataclysm (by, we now know, the collision of Scotland and England in the Ordovician period). A few yards
out to sea, the seaworn slabs form small upright walls, ready to tear out the bottom of their boat if they’d been careless with the oars. A few yards up from the tideline, just the same small walls, but half-buried in red sandstone.

Those small walls were carved by some much earlier sea: a sea that had risen, and dropped its sand around them, layer upon layer all up the cliffs above. In the bottom layer of that red sand are sea-smoothed pebbles, the beach shingle of that long-ago shoreline.

But what of the tilted greywacke layers underneath? Before whatever force had raised them on edge, they too had fallen, grain by grain, layer on layer, upon the floor of some even earlier ocean. And the grains of sand that formed the greywacke: from what even earlier content had they been washed out by rain and wind of what even more distant age? John Playfair’s mind “seemed to grow giddy by looking so far into the abyss of time”.

Scotland? No, not small at all. The rock platform at Siccar Point – just big enough for a BBC crew filming ‘Men of Rock’ last time I stood on it – is a three-minute trailer for an epic movie two billion years long. The tilted greywacke is the ocean floor that once lay between Scotland and England. When the two countries collided, about 450 million years ago, this sea-bed sludge was raised into the open air, tilted over, and crumpled like a used paper hanky. Those grey rocks lie within what we now call the Southern Uplands, emerging as sea cliffs at Mull of Galloway and Fast Castle. The Old Red Sandstone on top – by Scottish standards quite a young sandstone – is desert dunes and flash flood gravel, rubble eroded out from the great Caledonian mountain chain. Those mountains, Himalaya-high, rose as the two bits of continent crunched together. Their worn-away roots now make the Scottish Highlands.

A Handbook of Scotland’s Coasts: The Essential Guide for Beachcombers, Walkers, Wildlife Lovers, Rockpoolers, Birdwatchers, Foragers, Fossil-hunters and History Buffs, edited by Fi Martynoga, is out now published by Saraband Books (PB, £12.99)