Desperately Seeking Hutton’s Unconformity

 

Where IS Hutton’s Unconformity? A question we are often asked and one that is not easy to answer because, to the untrained eye, the rocks which comprise the unconformity don’t appear to be much different to the rest of the gnarled, grey, sea-bitten rocks that edge Arran’s northern coastline.

The issue of whether Hutton’s should be marked by a sign has been the subject of much discussion. Many think a sign would look intrusive in such a natural landscape. Many others believe that some kind of interpretation is vital if visitors are to fully appreciate the significance of the site. In fact, James Hutton himself is the remarkable ingredient in the story. In 1787, a time when Christendom believed the world was created in 4004 BC, Hutton, a lively and inquisitive man, farmer and soil-improver, came to Arran, looked at the formation of the rocks and recognised that the Earth must be much older than prevailing wisdom asserted.

Hutton applied modern scientific methods and reasoning to comprehension of the Earth’s history. Walking along the coast towards the Cock of Arran, he observed that younger sedimentary layers of sandstone lay above older Dalradian schists: this is the unconformity. He deduced that titanic processes of erosion and sedimentation, of uplift and great heat, must have created the world over long periods of time. His discovery made him come to be regarded as the father of modern geology although initially he faced outrage and accusations of blasphemy from some members of the church.

How to Find the Unconformity

 

From Newton Point (GR 931515) follow the Coastal Way. At first the path crosses grass then rocky ground. It’s about 1km to Hutton’s Unconformity.

Look up to your right for a long tree-filled fissure that makes a vertical line down the hillside. Hutton’s Unconformity is in line with this, in the rocks by the sea.

Eventually you come to a stone slab bridging a ditch (GR 936521). Stop here, don’t take the right turn of the path inland. Hutton’s Unconformity is on the sea side of the stone slab bridge. Look out for the two types of rock lying adjacent to each other, despite belonging to different geological ages. Notice how they slope at different angles.

A fun, educational way to learn about the local geology is to visit Lochranza Centre and do their geocaching trail (www.lochranzacentre.co.uk). I also recommend purchasing ‘Arran: Landscapes in Stone’ by Alan McKirdy, £7.99 from the Book and Card Shop in Brodick.‘The Arran Naturalist’, commemorative edition, £3.00, is also of interest if geology captures your imagination. It contains an excellent article about Arthropleura, a 2m long millipede, whose footprints from 300 million years ago remain clearly visible on rocks near Laggan. We sell this booklet in reception. You can also find out more about Arran geology at Arran Heritage Museum, Brodick.