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Lichen-streaked rocks line a grassy shoreline, a wooded headland curving into the sea beyond.
Isle of Arran

Hutton’s Unconformity

The rocks on Newton Shore near Lochranza where James Hutton found his first unconformity in 1787, a gap of about 190 million years between two layers.

Welcome

On the shore north of Lochranza, a few rocks by the water changed the way the world thinks about time.

Visited and photographed by Simon Hird

In 1787 the geologist James Hutton came to Arran to study its granite, and on Newton Shore he found what he was looking for: grey schist standing almost on end, with red sandstone lying gently across its tilted edges.

The schist is around 540 million years old and the sandstone about 350 million, so some 190 million years are missing between them. Hutton reasoned that laying down, tilting and wearing away rock on such a scale must take an unfathomable length of time, and his idea of deep time overturned the belief that the Earth was only a few thousand years old. The gap here is around three times the one at Siccar Point, his better-known site in Berwickshire.

An engraved sandstone block now marks the spot. It is a short, easy walk along the shore from the car park on Newton Road in Lochranza.

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The Daily for 31 October, from Scotland with love. A ring of standing stones set among mist and autumn birch
Before you go

Open at all times.

A short shore walk from the car park on Newton Road, Lochranza.

Found
1787, by James Hutton.
Gap
About 190 million years.
Marker
An engraved sandstone block.

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Did you know

Lichen-streaked rock ledges form a natural causeway along a shoreline, tidal pools collecting in the hollows.
Did you know

Deep time.

Hutton's reading of these rocks helped overturn the belief that the Earth was only 6,000 years old.

Lichen-streaked rocks line a grassy shoreline, a wooded headland curving into the sea beyond.
Did you know

Looking for granite.

Hutton came to Arran in 1787 to study granite and how it met the rocks around it.

Hidden Scotland

From our guide to Arran

A few rocks on the shore north of Lochranza changed the way the world thinks about time. In 1787 the geologist James Hutton found grey schist here standing almost on end, with red sandstone lying across its tilted edges. Some 190 million years are missing between the two layers. Hutton saw that laying down, tilting and wearing away rock on that scale must take an almost endless span of time, and his idea of deep time overturned the belief in a young Earth. An engraved stone marks the spot, a short, easy walk along the shore from Newton Road.

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Where it is

On Newton Shore, a short walk north from the car park on Newton Road, Lochranza, KA27 8HL.

Close byLochranza.
  1. Seals resting on lichen-covered rocks with others swimming in the seaArran Coastal Way with Thistle TrekkingUnder a mile 1 min by road
  2. Isle of Arran Heritage MuseumIsle of Arran Heritage Museum2 miles 3 min by road
  3. ARRAN Sense of ScotlandARRAN Sense of ScotlandThe island's bath, body and home fragrance maker, founded in 1989 and still making its products at Home Farm near Brodick, with a shop.2 miles 3 min by road
  4. The Sandwich Station beside an A841 sign showing Pirnmill, Machrie, Blackwaterfoot and LaggThe Sandwich Station, LochranzaSandwiches from the old fire station.19 miles 25 min by road
  5. Lochranza CastleLochranza CastleA castle on a spit in the loch.20 miles 27 min by road
  6. Lochranza DistilleryLochranza DistilleryArran whisky up the glen.20 miles 28 min by road
Directions
Arran's Cheese Shop entrance with red pillars and a wooden signboard outsideShoppingArran's Cheese Shop2.3 miles
Waterfall on a moorland stream with jagged peaks rising beyondAttractionsGlen Rosa2.4 miles
Waterfall tumbling through rocks below Skye's jagged Cuillin peaksAttractionsThe Blue Pool, Glen Rosa2.4 miles
Vintage pale blue van converted into a coffee stall beside treesRestaurantsThe French Fox, Brodick2.5 miles
Wooden dinosaur sculpture beside a black timber café with picnic tables on sandRestaurantsArran Botanical Drinks, Cladach2.6 miles
Deli staff stack pizza boxes beside shelves of tinned tomatoes and wine bottlesRestaurantsThe Parlour, Brodick2.7 miles
Curved sandy beach beside a coastal village, hills rising behind the rooftopsAttractionsBrodick Bay3.2 miles
Sandstone castle with turrets and chimneys viewed over garden flowers and lawnAttractionsBrodick Castle, Garden and Country Park3.3 miles
Cloud drifting over jagged rocky ridgelines with grassy slopes belowAttractionsCìr Mhòr4.1 miles as the crow flies

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What we have written about it and more on Arran.

ArticleThings to do on the Isle of Arran
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