It was reported in the news this week that Siccar Point has been selected as one of the world’s most internationally important geological locations, in a new list from the International Union of Geological Science. It was Scottish scientist James Hutton whose research into Siccar Point revolutionised our ideas about the Earth’s age and origin. Hutton had observed several sites where the top layers of rock were horizontal, and layers below were vertical, but it wasn’t until Siccar Point that these so-called ‘unconformities’ helped Hutton form his ground-breaking Theory of the Earth.

A new book by James Perman offers the first full biography of James Hutton, who is often overlooked among Enlightenment thinkers, but whose influence cannot be overstated. Read an extract about the incredible moment James Hutton realised the significance of Siccar Point, from James Hutton: The Genius of Time, below:

Extract from James Hutton: The Genius of Time by Ray Perman

In late spring 1788, Hutton found what was to become his most famous ‘unconformity’, at Siccar Point on the Berwickshire coast. With John Playfair, he had accompanied Sir James Hall home from Edinburgh to his estate 35 miles (56 km) south-east at Dunglass. The area had a particular interest because Dunglass Burn, the stream which runs down to the coast, was the boundary between the counties of East Lothian and Berwickshire, but more importantly almost the boundary between the vertical and horizontal strata.

‘To the north-west of this burn and beautiful dean are situated the coal, limestone, marl and sand-stone strata; they are found stretching away along the shore in a very horizontal direction for some time, but become more and more inclined as they approach the schistus of which the hills of Lammermuir to the south are composed.’

The three men, Hutton, Playfair and Hall, examined the banks of several burns (streams), but the strata were not as clear as they were on the coast, where the sea had worn away cliffs up to 200 feet (60m) in height. They took a boat from Dunglass Burn and, with the weather fine and the sea calm, were able to sail close to the shore. With mounting excitement as they moved along the cliff they saw the horizontal red sandstone and marl strata of the lowlands lifting towards the schistus of the uplands:

‘But, at Siccar Point, we found a beautiful picture of this junction washed bare by the sea. The sand-stone strata are partly washed away, and partly remaining upon the ends of the vertical schistus; and, in many places, points of the schistus strata are seen standing up through among the sandstone, the greatest part of which is worn away.’

Playfair, Hutton’s first biographer, was a first-hand witness to the event and his wonder at what he had seen and the way Hutton used it to tell the story of the Earth is evident in his account:

‘On us who saw these phenomena for the first time, the impression made will not easily be forgotten. The palpable evidence presented to us, of one of the most extraordinary and important facts in the natural history of the earth, gave a reality and substance to those theoretical speculations, which, however probable, had never till now been directly authenticated by the testimony of the senses. We often said to ourselves, “What clearer evidence could we have had of the different formation of these rocks, and of the long interval which separated their formation, had we actually seen them emerging from the bosom of the deep?”

We felt ourselves necessarily carried back to the time when the schistus on which we stood was yet at the bottom of the sea, and when the sandstone before us was only beginning to be deposited, in the shape of sand or mud, from the waters of a superincumbent ocean. An epoch still more remote presented itself, when even the most ancient of these rocks, instead of standing upright in vertical beds, lay in horizontal planes at the bottom of the sea, and was not yet disturbed by that immeasurable force which has burst asunder the solid pavement of the globe.

Revolutions still more remote appeared in the distance of this extraordinary perspective. The mind seemed to grow
giddy by looking so far into the abyss of time; and while we listened with earnestness and admiration to the philosopher who was now unfolding to us the order and series of these wonderful events, we became sensible how much farther reason may sometimes go than imagination can venture to follow.’

If they doubted Hutton’s theory before, Playfair and Hall were now convinced.