Arran Geology Trail

The Arran GEOLOGY Trail Walking The Sannox to Lochranza Coastal Path

By John S Watson There are not many places on Arran that feel lost, missed or left solely to the curious, or that just don’t conform. The great ridges and peaks are well documented and trodden to hardened trails of granite biscuit, the trails to the King’s Caves and Machrie Moor Stones are beat down with sandals and trainers. The coast is too jealously hugged by a slavish tourist road apart from, that is, the steep and precipitous north east coast between the villages of Sannox and Lochranza. Here the walker is rewarded with a five hour strip of un-engineered wilderness weaving it’s curious tale between cliff and sea on a ribbon of time that meanders in and out of geological eras in the easy stride of the human gait. One step can catapult you from Carboniferous to Permian and back again without a breath. Indeed, this walk is perhaps the open textbook of the geologist, an ambulatory timeline and palimpsest of fossilised snapshots.

Pic: Old Iron Float at Millstone Point

A short bus ride on the bumpy loop road drops you at Sannox, where a hop over the stepping stones allows access to the Arran Coastal Path. The beach at Sannox ends with a large white navigation mast, another which will appear later: they are part of a ‘measured mile’ marker system for boats in the Firth of Clyde to measure their top speed. They are essentially two sets of two poles with lights on each set of poles. As a boat passes the masts, the lights move out of parallax and line up - one can imagine stop-watches being pressed and throttles gunned forward until the next set of lights converge and thumbs depress and eyes look over the captain’s shoulders.

Pic: Fallen Rocks to Millstone Point

Pic: Raised Beaches at Millstone Point

Pic: Old Salt Pans Ruins

Pic: Fossilised Tracks of Arthropleura Giant Centipede

The path continues under old red sandstone conglomerate crags, heavy with moss and tangled over-arching birch. Just before the North Sannox burn the path veers left to a bridge, but a shortcut can be made on precarious stepping stones, if the river is low, to gain the Fallen Rocks path. The path straightens and moves through deep monoculture spruce for a while until opening out onto a pebble beach at the Fallen Rocks. This monolithic scree has tumbled from the giant conglomerate crag high above on Torr Reamhar marked on the OS map as Creag a’ Chaise (Gaelic: Cheese Rock). The consistency of this rock is indeed a kind of red crumbly cheese, snapping easily in the fingers, embedded with nuggets of quartz and all manner of ancient geologies that tumbled into a Devonian or Permian river delta to eventually form ‘fluvial conglomerates’.

Just past the Fallen Rocks the geology begins to mutate into limestone, specifically of the Upper Carboniferous era (300m years ago) when horsetails swayed in tropical breezes and fish grew limbs and flopped about limy sea-flats, gulping air into rudimentary lungs.

Sitting on the pebble beach stretching all the way to Laggan, it is easy to imagine hotter climates, lapping seas and the evolutionary zeal of our ancestors wanting to get their new-found feet onto land before turning into fossils.

Under the sweeping corrie of Crogan, the shoreline leads to Millstone Point, a shallow pebbled contour rather than a point, with some interesting limestone caves with the accoutrements and evening paraphernalia of summer fishermen. Fishing, of course, is nearly dead in the Clyde and it is no surprise to come across Laggan Cottages closed and boarded up with painted-curtain boards on the windows and a rather forlorn message on the blue door saying: ‘We’ll be Back Soon!’ It’s like the dinosaurs saying goodbye, pulling the door closed behind them and wandering off into oblivion. Fishing in the Clyde does continue but on more of a recreational, nostalgic basis rather than as a viable and sustainable community. Overfishing has been the generational sin of the 20th Century and the Clyde’s sea-bottom a dredged desert.

Further on from Laggan’s limestone cove are the old Laggan Salt Pans. These aren’t the flat acres of salty ground you might expect, rather a site of ruined stone buildings nestled up against a coalrich limestone outcrop in a hunkered-down birch wood. The small outcrops of coal allowed a salt business to thrive here in the early 18th Century known as the Duchess Anne’s Salt Pans, which were viable for only two decades until the coal ran out. Nearby are the deep black eyes of water-filled coal pits, from which the coal was extracted. The coal was burnt under iron salt pans for the ‘lumpmen’ and ‘wallers’ to skim off the salt from the evaporating brine, which was then shipped out from a harbour cove. The stonework of the old works, especially in the curved foreshore wall of the Panhouse, is clean and remarkable. The mood here reminds one of a miniKlondyke – of an energy that quickly dissipated in typically human boom and bust.

Beside these ruins, on the right side of a small cove under a small ruin, is an innocuous looking slab of flat Namurian sandstone lying on beds of shale and limestone and set at about an angle of 30 degrees to the horizontal. The layered rock has here been quarried away to reveal various geological planes of deposit. Looking carefully on one slab, especially in low light, an odd tram-trail of parallel markings curves deliberately across the once muddy sheet of stone. 350 million years or so ago, in the Carboniferous era, giant centipedes skittered over the earth and this is indeed an extremely rare and impactful example of fossilised tracks from such a beast, which would have grown to 2m in length and walked on a gait over a foot across. The sudden disappearance of the tracks into covering layers of more sandstone gives a brief geological Youtube moment of astonished imaginary film footage, with the deliberate curve of the tracks suggesting a purposeful beast intent on going somewhere fast. The clustered foot tracks of the centipede look just like a child has run his toy truck over unset cement. Once the eye accustoms to the ghostly imprint, time sloughs away in millennia and leaves a vertiginous sense of age and no little humility at the earth’s larger scheme of life and sudden death. Arthropleura this great carboniferous giant centipede - no longer exists, but his cousins can be found curling away in quick S-shapes if you kick over nearby stones.

Leaving the Salt Pans behind, the coastal path moves along under wooded cliffs towards the Cock of Arran, named after a boulder which looks vaguely like a cockerel. This marks the northerly tip of the island, and along the shore there are some impressive ‘unconformities’ of rock, specifically between dipped beds of red sandstone and carboniferous limestone. The idea of an ‘unconformity’ comes from the Enlightenment geologist James Hutton, who published his great book of time known as ‘The Theory of the Earth’ in 1795. The Borders geologist had an instinct for deep time, more so than his contemporaries, and sought out these ‘un-conforming’ beds of geology to prove that eras of time fed each rock deposition and that furthermore tectonics moved them around in even greater swathes of time. The age of the Earth was so uncomprehendingly old it led him to the enlightening conclusion that he could ‘see no vestige of a beginning and no prospect of an end’. Rocks were recycled as easily as glass bottles, over and over again, and the great landfill of geological time was a churning, moving beast of fathomless time. Moving along this coast it is easy to feel the sudden changes in the geology as dropoffs into another dimension, great narrow gorges of time, across which you can stand eye to eye with Arthropleura.

If you are lucky, passing by a distinctive red sandstone roof, you may spy a black hole disappearing into the vegetation. This is Ossian’s Cave (NR 962 516). Its entrance hallway displays low carvings of tall sailing ships but one suspects these are contemporaneous to the dated initials of 1941 nearby. Perhaps some local fisherman eager to impress grandchildren with tales of seafaring giants who lived in caves? Further in, the cave squeezes through a narrow womb into pitch darkness. A torch or tea-light reveals a vast cavern, its walls covered in a spooky silver mildew, perhaps the secret silver horde of Ossian himself?

Around the Cock of Arran, the rock returns to red sandstone, specifically aeolian and fluvial (wind and water) sandstones from the Cretaceous era. Some of this ochre red rock outcrops on the foreshore and is worn into fantastic layers of fine sandstone and thicker cakes of conglomerate. The finer sandstone exhibits the swirling signature of sand-dunes and wind-shaping before being petrified and revealed to us by the erosive power of the

Pic: Geological Unconformity: Red Sandstone on White Limestone

Pic: Wave worn rock sculptures at Cock of Arran

Pic: Laggan Cottage

Pic: Carving in Ossian’s Cave

ocean. Despite the briny setting, these rocks are from an arid era when Scotland sat in tropical climates and dust-storms raged and red dunes crept over the land, whilst the occasional biblical flood deposited thicker conglomerate pebbles and quartz.

Pic: Entrance to Ossian’s Cave

Pic: Silvered Rock in Ossian’s Cave

As the shore turns westward there is a complex labyrinth of boulders to negotiate known as An Scriodan. These blocks take a little negotiation, but it is interesting to note old yellow waymarking spots of paint have been camouflaged under black paint by someone who disliked the idea of marking the way at all! The boulders suddenly deposit you on a layered stone beach with the waters lapping round sandstone boulders and pale shimmering plates of limestone pebble. The far end of the beach opens out to a community of fishing cottages known as The Fairy Dell, with a path linking them over the hill to North Newton.

Continuing along by the coast the rock changes to pale schists and just before Newton’s Point, by a raised beach in line with the last house on the headland, you may come across Hutton’s Unconformity. This famous geological site looks like nothing at all to the casual observer – a tilted slab of Devonian sandstone overlaying a differently angled bed of Cambrian schist – but it was the feather in the hat of James Hutton’s proof for a ‘Plutonic’ geological theory of massive time, tectonics, heat and shape-shifting in geology, rather than the gentle depositional theory of the ‘Neptunists’. This 18th century war of theories was won resoundingly by Hutton and presaged the work of Charles Lyell and by default Charles Darwin who used the deep time theory as his backdrop to the theory of evolution. The link is not unjust, for Hutton saw in this odd unconformity of rocks two eras of time, each of vastly different pedigree, compressing over 100 million years into the width of a camera lens.

The pleasant open plain of Newton Point is finally reached after 4 or 5 hours on the hoof. The storm beaches of pebbles rest on marshy grass, someone nearby has made a fair attempt at a Neolithic stone circled and at Newton Point itself, a smile is raised by a plaque dedicated to the weary geological wanderer. The path meets tarmacadam by a couple of granite erratics and our present world regained at Lochranza with its distinctive promontory castle.

Pic: Aeolian Sandstones

Pic: Fairy Dell Fishing Cottages

Pic: Hutton’s Unconformity at Lochranza

Pic: the tyre-track trail of Arthropleura

Itinerary 4-5 hours walk Approx.14km Ferry Ardrossan to Brodick 9.45am-10.40am Bus Brodick to Sannox 10.50am-11.20am 1. Sannox to North Sannox Burn ~ 20 min 2. North Sannox Burn to Fallen Rocks ~ 30 min 3. Fallen Rocks to Millstone Point ~ 30 min 4. Millstone Point to Laggan Cottage ~15 min 5. Laggan Cottage to Salt Pans ~ 15 min 6. Salt Pans to Cock of Arran ~ 30 min 7. Cock of Arran to Fairy Dell ~ 40m 8. Fairy Dell to Newton Point ~ 20 min 9. Newton Point to Lochranza ~ 20 min Stops ~ 1 Hour Bus Lochranza to Brodick 3.38-4.20 pm Ferry 4.40 pm-5.35pm