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Hutton, James

Hutton, James

Hutton, James, 1726-97, Scottish geologist, chemist, and naturalist. He was initially attracted to chemistry; he entered the legal profession at the Univ. of Edinburgh; turned to medicine, as it closely resembled chemistry; and then became a farmer to allow him to study rocks and be able to pursue his interests in geology. He formulated controversial theories of the origin of the earth and of atmospheric changes (see uniformitarianism) that paved the way to modern geological science. After 1768, he moved to Edinburgh to discuss his ideas with other scholars including the physician and mathematician John Playfair, and chemist Joseph Black. Hutton started a controversy by standing against the popular Neptunists (rocks developed in a great flood) and the Plutonists (all rocks are of igneous origin) schools, proposing the theory of uniformity of causes, concluding that the earth's history can be explained by observing the geological forces now at work, because these forces are identical to the ones that operated in the past. By studying the Devonian Old Red Sandstone along the Scotland coast, he discovered that sedimentary rocks originated from, not a single flood, but a series of successive floods; noted that the intrusion of igneous rocks were distinct from sedimentary deposits; recorded the gradual actions of geomorphic processes; and discussed the lengths of geologic time. His ideas influenced Charles Lyell's Principles of Geology, which in turn influenced Charles Darwin's theories of adaptive evolution. Hutton's great work was The Theory of the Earth (2 vol., 1795; MS fragment for Vol. III ed. by Archibald Geikie, 1899); it was simplified by John Playfair as Illustrations of the Huttonian Theory of the Earth (1802).

See study by E. B. Bailey (1967).

(born June 3, 1726, Edinburgh, Scot.—died March 26, 1797, Edinburgh) Scottish geologist, chemist, and naturalist. After short careers in law and medicine, he followed his interest in chemistry and developed an inexpensive manufacturing process for sal ammoniac. He settled in Edinburgh (1768) to pursue a life of science. In two papers presented in Edinburgh in 1785 (published 1788), he elaborated his theory of uniformitarianism. Its ability to explain the Earth's geologic processes without reference to the Bible and its emphasis on an immensely long, cyclical process of erosion, deposition, sedimentation, and volcanic upthrust were revolutionary.

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Hutton's Unconformity is the name given to various famous geological sites in Scotland. These are places that were identified by 18th century Scottish geologist James Hutton as an unconformity, which provided evidence for his Plutonist theories of Uniformitarianism and about the age of the Earth.

Theory of rock formations

Hutton hit on a variety of ideas to explain the rock formations he saw around him, and after some 25 years of work, his Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe was read to meetings of the Royal Society of Edinburgh in 1785. Later that year Hutton read an abstract of Concerning the System of the Earth, its Duration and Stability to a Society meeting, and had it printed and circulated privately.

In it, he outlined his theory that the "solid parts of the present land appear in general, to have been composed of the productions of the sea, and of other materials similar to those now found upon the shores. From this he deduced that the land was a composition which had been formed by the operation of second causes in an earlier world composed of sea and land, with tides, currents, and "such operations at the bottom of the sea as now take place" so that "while the present land was forming at the bottom of the ocean, the former land maintained plants and animals; at least the sea was than inhabited by animals, in a similar manner as it is at present", and that most, if not all, of the land had been produced by natural operations involving the consolidation of masses of loose materials collected at the bottom of the sea, followed by the elevation of the consolidated masses to their present position.

Hutton's unconformities

Angular unconformities had been noted by earlier geologists who interpreted them in terms of Neptunism as "primary formations", so Hutton wanted to examine such formations himself to look for support for his theory of Plutonism. On a trip to Arran in 1787 he found his first example of an unconformity, but the limited view did not give the information he needed. It occurs where some vertically oriented Dalradian schists are overlain by more recent (possibly Carboniferous) horizontal sandstone. The difference in dip between the two rock layers is now particularly obvious when at the site.

Later in 1787 Hutton noted what is now known as the Hutton Unconformity at Inchbonny, Jedburgh, in layers of sedimentary rock. He later wrote of how he "rejoiced at my good fortune in stumbling upon an object so interesting in the natural history of the earth, and which I had been long looking for in vain." That year, he found the same sequence in Teviotdale.

In the Spring of 1788 he set off with John Playfair to the Berwickshire coast and found more examples of this sequence in the valleys of the Tour and Pease Burns near Cockburnspath. They then took a boat trip from Dunglass Burn east along the coast with the geologist Sir James Hall of Dunglass. They found the sequence in the cliff below St. Helens, then just to the east at Siccar Point found what Hutton called "a beautiful picture of this junction washed bare by the sea". Continuing along the coast, they made more discoveries including sections of the vertical beds showing strong ripple marks which gave Hutton "great satisfaction" as a confirmation of his supposition that these bed had been laid horizontally in water.

Playfair wrote:

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