The Scottish geologist Sir Roderick Impey Murchison (1792-1871) established the Silurian as a new geological system and cofounded the Devonian system.

Roderick Murchison, descended from an old Highland family, was born in Scotland on Feb. 19, 1792. After a time in the army in the Peninsular War, he married and, having ample means, took up fox hunting and an interest in art and antiquities. Influential friends, aided by his wife, persuaded him to pursue a scientific career, and from the age of 32 he devoted himself to geology.

In 1831 Murchison began his great research into the mass of hitherto geologically unknown graywacke rocks, that is, Lower Paleozoic, underlying the Old Red Sandstone in South Wales and the Welsh Borderland. His monumental work The Silurian System (1839) geologist In the same year he and Adam Sedgwick established the Devonian system. In 1841, after explorations in Russia with French colleagues, he proposed the name Permian for yet another worldwide geological system, the uppermost of the Paleozoic. The Geology of Russia in Europe and the Ural Mountains was published in 1845. The book Siluria (1854 and subsequent editions) surveyed those ever-widening regions which he was incorporating in his Silurian domain.

Murchison was involved in the two most important geological controversies of the 19th century. The first was the unfortunate and bitter argument over the Cambrian and Silurian systems, in which the other protagonist was Sedgwick. Here Murchison's case was undoubtedly the stronger. The other was the crucial question of the geological structure of the Highlands of Scotland. Here Murchison was only involved retrospectively, and it turned out that his interpretation was wrong.

In 1855 Murchison became director general of the Geological Survey of Great Britain. Meanwhile he had presided over the Geological Society, the Geographical Society, and the British Association for the Advancement of Science. He was knighted in 1846 and was made a baronet in 1866. Among his many honors from British and foreign institutions was the Wollaston Medal, the highest award of the Geological Society.

Murchison was one of the most distinguished geologists of the 19th century. His liberality and social position plus the pride he took in his science were of immense value in furthering the cause of learning in Britain. He died in London on Oct. 22, 1871.