Hutton’s uncomformity and Arran’s contribution to the beginning of Geology

With the success of the recent Geofest that took place in Arran in October, and continuing progress being made with the island’s Geopark project, local resident Jim Henderson tells the story of one of the founding fathers of Geology, and the unconformity in Lochranza that is at the heart of the discipline.

Hutton’s uncomformity at Newton Lochranza.

The Father of Geology

James Hutton (1726 – 1797)
Physician, Naturalist, Chemist, Farmer and Geologist.

When Hutton was a young adult there was no such science as Geology.
James Hutton was born in Edinburgh on the 3rd June 1726. When he was a young child his father died. Despite his mother’s domestic problems, he was educated in the local High School and at Edinburgh University where he was inaugurated at the age of 14 and developed a passionate interest in scientific inquiry. Aged 17 he began work as an apprentice to a lawyer, who advised him to continue his studies in a field more akin to his scientific mind. He chose to study Medicine, which was similar to one of his favourite subjects Chemistry. After a further three years at Edinburgh University he completed his medical studies in Paris gaining a degree in 1749.

On returning to Edinburgh, events and circumstances at the time dictated a change from the medical profession. From his father he inherited a small property at Slighthouses in Berwickshire and he resolved to devote himself to agriculture. He went to study farming practices in Norfolk, and travelled to Holland, Belgium and the north of France as well. During this time he studied the surface of the land, which had a crucial influence on his geological ideas, instigating an interest which was to become his legacy.

In 1754 Hutton returned to his own farm in Berwickshire, where he introduced new farming practices and husbandry (methods which are still in use to this day) Under his management, the farm became one of the best and most productive in the area. After a period of 14 years, having achieved as much as he could with the farm, he leased the property and returned to Edinburgh.He never married and spent most of his life in the company of his three sisters.

In Edinburgh he often met up with friends, where he was able to converse, communicate and express his ever searching mind to research literary and scientific episodes. Among his friends were some of the outstanding minds of the time, James Watt (engineer), Adam Smith (philosopher), Robert Burns (poet), John Playfair (scientist), David Hume (philosopher/economist), Joseph Black (physician), Sir James Hall (geologist) and Francis Hutcheson (Prof. of Philosophy).

Around the period of 1765 Geology in any term did not exist. Mineralogy however was making progress. Hutton began to conceive more expansive ideas; he desired to trace the origin of the various rocks and minerals to understand the history of the earth. His research and studies established Hutton as the father of Geology.

Between 1767 and 1774 he was a member of the committee [assisting with his knowledge of mineralogy] instrumental in the construction of the Forth & Clyde canal. He was also recognised as one of the hero’s of the Scottish Enlightenment period (mid-18th Century).

He travelled all over the lowlands of Scotland by horse and sailing boats, studying the landscape and geology of the terrain. In 1787 aged 61 he was attracted to visit Arran by the rugged slopes and coastline of the Island. The science of Geology was in its infancy, many problems existed and new ideas were being formulated. Arran’s varied geology provided much evidence for Hutton’s active mind. The research established during his time on Arran was influential to recording his first volume Theory of the Earth.

At the north of the island of Arran, between Newton and Laggan, Lochranza, he came upon an outcrop of rock (now known as Hutton’s unconformity) – a rock stratum in schist, inclined in angle of one direction, but overlain by sandstone formed at a different angle, a process of erosion, occurring over a long period of time (many million’s of years).

The outcrop was only in the region of 300 metres in length, made up of old red sandstone, carboniferous sandstone and new red sandstone, lying above Dalriadan schist’s of late Precambrian with Permian conglomerates and Aeolian sands with seams of carboniferous calcareous sands and limestone.
This find supported his ‘plutonism and uniformitarianism’ theory that the earth was much older than previously considered by academics and theologians.

The following year he found the graphic proof he had been searching for at Glen Tilt in the Grampian Mountains, where granite veins had been injected into the surrounding rock. On returning to investigate an area near Berwick accompanied by the geologist Sir James Hall and scientist John Playfair, Hutton’s observation of the unconformity at Siccar Point Cockburnspath, Berwickshire became his most famous of discoveries.

He argued and investigated the evidence that the rock formation had been created, deformed, uplifted, eroded and overlain by sediments in the sea. The rock again uplifted and deposited to allow for erosion to take place over a long period of time to create the unconformity involving Devonian and Silurian strata. He also discovered that heat generated within the earth was involved with mineralisation and proved the existence of unconformities in rock layers. His theory liberated science and philosophy, changing the idea that the earth was only about 6,000 years of age, and created in biblical terms around 4004 B.C.

The evidence uncovered by his explorations gave extraordinary and important facts to the understanding of the natural history of the earth.

In Hutton’s later years his evidence convinced his friends Playfair and Hall, but many others were not.
A leading Irish academic Dr. Richard Kirwan FRS 1733 – 1812 suggested that Hutton’s theories were blasphemous and argued against the Huttonian theory. In failing health Hutton was unable to respond, but his books were being published, outlining his theories and illustrating the proof he had accumulated.
By 1795 two volumes of his work titled ‘Theory of the Earth’ were published, he was working on a third volume when he died in March 1797. His friend John Playfair completed his work from the draft Hutton had been preparing titled ‘Illustrations of the Huttonian Theory of the Earth’ which was published in 1802.

It was another 35 years before Charles Lyell wrote ‘Principles of Geology’ which made Hutton’s ideas the foundation of modern Geology. It also provided Charles Robert Darwin FRS 1809-1882 with the inspiration for his ‘Theory of Evolution’. Much later in the period 1882 – 1905 even more evidence was uncovered built on Hutton’s theories by Sir Roderick Murchison (1792-1871), Charles Lapworth (1842-1920), John Horne (1848-1928) and Sir Edward Bailey (1881-1965) who proved that Glencoe was the result of a Coldera volcano collapsing within its self. The violent process of old rock, ending up on top of younger rock, in layers came from a process of a sideways movement, which pushed up the earth crust to form mountains.

The landmass of Scotland and England were connected to different continents. A massive fault 500 million years ago brought them together, creating the Scottish Highlands. Remains of the Highland boundary fault extend between Kintyre and Stonehaven running through the North of Arran and Bute.

Jim Henderson

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