MURCHISON, SIR RODERICK IMPEY (1792-1871), British geologist, was born at Tarradale, Scotland, on Feb. 19, 1792. Educated at Durham and the military college, Great Mar low, he landed (1808) with Wellesley in Galicia, and was pres ent at the actions of Rorica and Vimiera. Under Sir John Moore he took part in the retreat to Corunna.
In 1818 he sold his paternal property in Ross-shire and settled in England, where he took to field sports. He soon became one of the greatest fox-hunters in the midland counties. Sir Humphry Davy persuaded him to attend lectures at the Royal Institution. He joined the Geological Society of London, and, with the help of W. H. Fitton, prepared his first scientific paper, read to the society in 1825. In three years he had explored large parts of England and Scotland, had obtained materials for three impor tant memoirs, as well as for two more written in conjunction with Sedgwick, and had risen to be a prominent member of the Geological Society and one of its two secretaries. He then ex plored with Lyell the volcanic region of Auvergne, parts of south ern France, northern Italy, Tirol and Switzerland. Later, with Sedgwick as his companion, he attacked the difficult problem of the geological structure of the Alps, and their joint paper giving the results of their study is one of the classics in the literature of Alpine geology.
In 1831, at the suggestion of Buckland, he visited the Welsh border, to discover whether the greywacke rocks underlying the Old Red Sandstone could be grouped into a definite order of suc cession, as the Secondary rocks of England had been made to tell their story by William Smith. For several years he worked in that region. The result was the establishment of the Silurian system —under which were grouped for the first time a remarkable series of formations, each containing distinctive organic remains older than and very different from those of the other rocks of England. These researches, together with descriptions of the coal-fields and overlying formations in south Wales and the English border coun ties, were embodied in The Silurian System (1839), illustrated with map, sections, pictorial views and plates of fossils. As years passed on the types of existence brought to light by him from the rocks of the border counties of England and Wales were ascertained to belong to a geological period of which there are recognizable traces in almost all parts of the globe. Thus the
term "Silurian," derived from the name of the old British tribe Silures, soon passed into the international vocabulary.
The establishment of the Silurian system was followed by that of the Devonian system, an investigation in which, aided by the palaeontological assistance of W. Lonsdale, Sedgwick and Murchison were fellow-labourers, both in the south-west of Eng land and in the Rhineland. Murchison then projected an im portant geological campaign in Russia. He was accompanied by P. E. P. de Verneuil (1805-73) and Count A. F. M. L. A. von Keyserling (1815-91), in conjunction with whom he produced a magnificent work on Russia and the Ural Mountains (1845). In 1846 he was knighted, and in the same year he presided over the meeting of the British Association at Southampton. During the later years of his life a large part of his time was devoted to the affairs of the Royal Geographical Society, of which he was in 1830 one of the founders, and he was president 1843-45, 1851 53, 1856-59 and 1862-71. He was interested in the work of Liv ingstone. He devoted his last year to the Scottish Highlands, where he believed, erroneously, he had succeeded in showing that the vast masses of crystalline schists, then supposed to be part of what used to be termed the Primitive formations, were really not older than the Silurian period, for that underneath them lay beds of limestone and quartzite containing Lower Silurian (Cambrian) fossils.
In 1855 Murchison was appointed director-general of the geo logical survey and director of the Royal School of Mines and the Museum of Practical Geology in Jermyn street, London. He prepared successive editions of his work Siluria 5th ed., 1872), which was meant to present the main features of the original Silurian System together with a digest of subsequent discov eries, particularly of those which showed the extension of the Silurian classification into other countries. In 1863 he was made a K.C.B., and three years later was raised to the dignity of a baronet. The learned societies of his own country bestowed their highest rewards upon him, and he received many foreign honours.
Murchison founded a chair of geology and mineralogy in the University of Edinburgh. He died on Oct. 22, 1871. Under his will there was established the Murchison medal and geological fund to be awarded annually by the Geological Society.
See Sir A. Geikie, Life of Sir Roderick I. Murchison (i875).