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James Hutton (3 June 1726 - 26 March 1797), pioneer of the science of geology, was one of the extraordinary men of science and learning who flourished in Edinburgh in the latter part of the 18th century, in a period called the Scottish Enlightenment.

He was born in Edinburgh, and after briefly studying law, and then medicine, achieving an MD degree in Holland in 1749, he took up farming. In 1768 he turned to scientific investigation.

There are several localities known as 'Hutton's Locality', where Hutton observed features in the rocks that were counter to the prevailing view of the time.

Geologically, the conventional wisdom was that all the rocks on Earth had precipitated out of sea water at the time of the Flood. The part played by igneous rocks was entirely unrecognised.

On Arthur's Seat in Edinburgh Hutton noted that the sedimentary strata had been deformed, and that the deformation resulted from molten rock being intruded into the pre-existing rocks. The evidence for that is that the deformed sediments had been baked, both above and below, by the heat of the magma as it forced its way through the sediments. Therefore Hutton could demonstrate that the magma post-dated the sandstone, and that it had been molten or semi-molten when it was intruded.

In Glen Tilt, Hutton observed pink crystalline rock interfingering with grey schists, again showing that the crystalline material must have been intruded in a molten state into pre-existing rocks, and hence that not all rocks were of the same age, or formed by precipitation from sea water.

The Irish archbishop James Ussher (1581-1656) had counted back the generations listed in the Book of Genesis and calculated the time and date of the Creation as 'the entrance of the night preceding the 23rd day of October... the year before Christ 4004'; that is, around 6 pm on 22 October 4004 BC, by the Julian calendar.

At Siccar Point, on the Isle of Arran, and at Jedburgh, Hutton observed rock layers at a sharp angle to overlying horizontal sedimentary strata. He deduced that the underlying layers must have been deformed and tilted, and that for this to take place meant that the process of rock formation must have been going on for an inconceivable length of time.

These ideas were totally revolutionary when Hutton published his findings in a series of papers under the title 'Theory of the Earth', presented to the Royal Society of Edinburgh in the 1780s. The basis of his theory was that all geological phenomena could be explained by observable processes, and that these processes had been operating since time immemorial and would continue operating in all time to come.

Although fiercely opposed by the churches and by the geological establishment, Hutton's theory, termed uniformitarianism, is now accepted as the fundamental principle of the scientific study of geology.

Created: Mon, 25 Nov 2019, Updated: Fri, 7 Apr 2023