The scientific study of the composition and structure of the earth’s crust, its history, and the processes that shape it. As such, it considers the physical forces that act on the Earth, the chemistry of its constituent materials, and the biology of its past inhabitants as revealed by fossils. The word ‘geology’ was first used by Jean-André De Luc (1727-1817) in 1778, and was then given a more formal expression by Horace-Benedict de Saussure (1740-1799) in 1779. The first modern geologist is usually considered to be James Hutton (1726-1797) who argued, in a paper to the Royal Society of Edinburgh (1785) and later in his book The theory of the earth (1795), that the earth must be much older than was supposed so as to allow enough time for mountains to erode and for sediments to form new rocks. His theory was avidly supported by Charles Lyell (1797-1875) who made Hutton’s writings more accessible to the general public. Both Hutton and Lyell influenced Charles Darwin (1809-1882) in his writing of The origin of the species (1859). Lyell’s influence stemmed from his three volume The principles of geology: being an attempt to explain the former changes of the earth’s surface, by reference to causes now in operation (1830-33), the first volume of which Darwin read on his journey in the HMS Beagle (1831-1836). In this book, Lyell promoted what the mineralogist and polymath William Whewell (1794-1866) termed ‘unformitarianism’ in opposition to the prevailing view of ‘catastrophism‘. The latter, derived from the Book of genesis, held that the composition and structure of the earth had been brought about by a series of cataclysmic upheavals such as The Flood. Uniformitarianism, in contrast, maintained that the earth’s history consisted of gradual changes wrought by tangible and continuing natural forces such as erosion and sediment deposition, together with the less frequently occurring events of volcanic action and earthquakes. This aspect of Lyell’s uniformitarianism was one of the sources of influence on Darwin’s derivation of his theory of natural selection. While Lyell had considerable reservations about this theory, he nevertheless encouraged Darwin to publish it, and in doing so co-sponsored a reading of The origins at a meeting of the Linnean Society in London (1858), jointly with a paper by Alfred Russel Wallace outlining his own theory of natural selection. According to Loren Eiseley in his book Darwin and the mysterious Mr. X (1979), Darwin is reputed to have said, “I feel as if my books came half out of Sir Charles Lyell’s brain (p. 31)”. Thus, the theory of natural selection owes much to Lyell in particular and to geology more generally.
See Darwinism, Palaeontology, Theory of natural selection, Theory of population pressure