Sir Charles Lyell, first baronet, (1797-1875, APS, 1842) was a geologist and lawyer, whosePrinciples of Geology explained “former changes of the earth’s surface” by means of “modern causes.” Critical of the “catastrophist” views of many contemporary geologists, Lyell considered the earth “a system of balanced antagonistic processes,” a theory later described as uniformitarian. Although he rejected Jean Baptiste Lamarck’s theory of species mutability early in his career, later he favorably reviewed the arguments of Charles Darwin for natural selection as the evolutionary mechanism behind the emergence of new species.

The eldest son of Charles Lyell and Frances Smith, Lyell developed a passion for natural history as a boy in New Forest, Forfarshire in Scotland. He was educated in private schools in Midhurst, Sussex county England and entered Exeter College, Oxford in 1816, where he attended William Buckland’s lectures on mineralogy and geology for three years. Lyell graduated B.A. in 1819 with a second class in classical honors. He received an M.A. in 1821, before entering Lincoln’s Inn to prepare for a legal career. Nevertheless, Lyell aimed to become a man of science, and to this end Buckland recommended him for membership in the Geological Society, which he joined together with the Linnean society.

Lyell began Geological research in 1821, after meeting Gideon Mantel, an English obstetrician, geologist and paleontologist, working on “Secondary” formations of rocks in Sussex. Lyell also studied younger “Tertiary” formations of the Chalk area of Dorset and Hampshire developed during the Cretaceous period. So, by the age of 24 Lyell was doing the kind of geological research (later called stratigraphy) then practiced by other members of the Geological Society.

In 1822 Lyell was called to the bar; nevertheless, geology quickly became more important to him than the Law. In 1823 he was elected secretary of the Geological Society of London and spent the summer in Paris, making the rounds of French scientific circles, and improving his French, then the language of science. He met established figures of the French scientific community, including Georges Cuvier and Alexandre Brongniart (1770-1847, APS 1819). Brongniart’s former student Constant Prévost took time to show him the formations of the Paris basin.

Lyell’s meeting with Prèvost proved a critical juncture for his career, since Prèvost convinced the young Scot that the formations outside of Paris could have been deposited under the similar conditions as those existing in present day lakes and seas, the result of so-called “modern causes,” processes observable in the present world. Later that year, Lyell studied the sediments he found in a small, recently drained lake in Kinnordy, and, in his first scientific paper presented to the Geological Society Lyell asserted the lake deposits were very similar to some of the Parisian rocks he had examined. He found no sharp contrast between the “former world” and the present one. Consequently, he maintained that “modern causes” are adequate to explain traces of the remote past. This paper presented the basic idea for all of his future work in geology.

By 1825 Lyell’s father was displeased that his son had not established himself in a successful Law practice. Consequently, Lyell felt compelled to spend more time on legal work in 1826. However, the same year Lyell was elected a fellow of the Royal Society, and was also appointed foreign secretary of the Geological Society. He was also becoming known in British intellectual circles, beyond geology. In addition to these memberships, in 1825 Scottish publisher John Murray invited Lyell to write for the ToryQuarterly Review. The position afforded Lyell a much needed source of income, but also provided him a venue for promoting the causes of moderate political reform, state sponsorship of the sciences and the reform of the ancient universities.

In an 1826 essay in theQuarterly Review on the publications of the Geological Society Lyell extolled the group for pursuing a science of careful observation, rather than speculative theorizing. While sticking to the accepted view that complex organisms had appeared over time, as the earth slowly cooled, he distinguished himself from other members of the Geological Society by suggesting that “modern causes” might be responsible for much more geological development than most contemporary geologists admitted. Lyell’s essays for theQuarterly Review concluded with a review of a new book on French geology by his friend George Scrope in which he agreed with the author that what was necessary to explain geological development was simply “Time! Time! Time!” Also, at this time Lyell began to plan a book to introduce his view that geology would only become truly scientific, if it was based on “modern causes,” since only these could be directly observed.

In 1828 Lyell joined Scottish geologist Roderick Murchison (1792-1871, APS 1860) in a fieldwork tour of the European continent. Heading first for Auvergne in central France, they moved on to Italy, where Lyell developed a rough timeline for the most recent era of the earth’s geologic development represented in Tertiary rock formations. Back in England after the continental tour, he presented his findings to the Geological Society, incorporating the evidence of a broad fossil survey in Tertiary formations by French conchologist Gerard Deshayes.

In July 1830 Lyell published the first volume ofPrinciples of Geology, recalling the title of Newton’s revolutionary Principia Mathematica. In it he attempted “to explain the former changes of the earth’s surface, by reference to causes now in operation.” He provided a systematic description of these so-called “modern causes” such as volcanoes, earthquakes, sedimentation and erosion, taken from a range of sources, including accounts of expeditions and voyages. However, Lyell’s main source was a major compilation of the physical and topographical changes recorded in human history published by Karl von Hoff in 1822-1824. He learned German specifically to read the work, and employed Hoff’s data to demonstrate his view that the earth is “a system of balanced antagonistic processes,” erosion balanced by sedimentation and crustal elevation offset by crustal subsidence.

Lyell began his book with strong criticism of contemporary geologists. He described the history of science as a protracted struggle between scientists with views similar to his own and those, who invoked catastrophes at every turn. Lyell described his own outlook, which stressed the “uniformity” of nature, as the genuinely scientific view, while equating his opponents with writers who claimed biblical authority to limit the earth’s history to a few thousand years. He lumped geologists, like his mentor Buckland with these literalist writers because he identified the “geological deluge” with the biblical flood. Nevertheless, Buckland had rejected biblical literalism by assuming an unlimited period of time for the earth’s development. Lyell’s goals were to make geology truly scientific, but also “to free the science from Moses.” The book received mixed reviews. Reviewers found his thesis about the power of modern causes significant and persuasive, but thought his criticisms of other geologists grossly unfair. Likewise, they considered Lyell’s skepticism about organic progression utterly unconvincing.

In 1831, Lyell was appointed professor of geology at the new King’s College in London. He lectured there during 1832 and 1833, offering similar lectures at the Royal Institution. But he resigned from King’s College in 1833 and gave no further lectures at the Royal Institution, since the salary provided too small an income to justify the distraction from his research and writing.

While doing field work in Germany, during the summer of 1831, Lyell met the 23-year old Mary Horner, daughter of the Whig reformer and geologist Leonard Horner. They married on July 12, 1832, after a geological honeymoon, settling in Hart Street, Bloomsbury in London near the British Museum and the Geological Society’s headquarters in Somerset House. Mary was well educated and fluent in French and German, and soon began helping her husband with translation, compensating for his poor eyesight. The marriage would remain childless.

Lyell produced the second volume of the Principles in 1832, dealing with “modern causes” in the organic realm, particularly the relationship between organisms and their enviornment. He rejected Jean Baptiste Lamarck’s theory of the incessant mutability of species, maintaining that species are “stable entities” that appear and become extinct piecemeal in time and space. He attributed extinctions not to catastrophes, but to the gradual changes in the environment explained in his first volume. It was in his review of Lyell’s second volume that William Whewell coined the terms “uniformitarian” and “catastrophist” for the two opposing schools of geologists.

In the third and final volume of the Principles Lyell laid out his time scale for the Tertiary era, which formed its core theme. He used the lengthy lists of fossilized species from Deshayes’s Paris survey of Tertiary formations to infer a chronological order for the era. Based upon the incidence of the fossilized remains of “recent” species in the various Tertiary strata, Whewell proposed to Lyell Greek-based names for successive periods of Tertiary time. The “Eocene” or early recent strata, the “Miocene” or middle recent strata, and the “Pliocene” or “almost” recent strata. Lyell maintained that the entire Tertiary era exemplified the essential “uniformity” of the earth throughout geologic time. Lyell laid to rest the alleged evidence of radically different conditions in earlier eras with his concept of “metamorphism”. He pointed out that deep burial within the earth’s crust of its oldest rocks had destroyed their fossils and altered them beyond recognition. Likewise, sedimentary strata were transformed by heat, being converted to crystalline rocks, when submerged below the earth’s surface. Lyell called these rocks “metamorphic” rocks.

In 1834, Lyell presented the Bakerian lecture at the Royal Society and afterward received the Society’s royal medal. However, it was awarded specifically for his work on modern causes, and not for his more controversial claims. In particular, even Lyell’s strongest supporters were critical of his rejection of a directional history of the world, while other critics took exception with his rejection of the mutability of species. In 1835-37 Lyell served as president of the Geological Society, and used his anniversary addresses to examine current geological research in light of his own approach to science. Although his notions of modern causes continued to gain headway among geologists, other aspects of his work did not. The uneven evaluation of his ideas influenced Lyell to divide his research into two parts. Subsequent editions of thePrinciples, beginning with the sixth edition (1840) focused purely on the interactions of “modern causes”. Lyell planned a separate book on the use of fossil mollusks in Tertiary geology, but this never appeared.

In 1838 Lyell produced a book entitledElements of Geology that examined the whole stratigraphical record from the most recent to most ancient formations. The work interpreted terrestrial processes in terms of geological uniformity for a wide audience of educated lay readers. Written in a clear and persuasive style, the book also appeared in American editions and French and German translations, giving Lyell’s ideas international currency.

In 1841-42 Lyell was invited to the United States to give the Lowell lectures in Boston, after which he and his wife traveled widely, publishing a two volume record ofTravels in North America, containing his geological, political and social observations. In an encore appearance they returned to America in 1845-46, when he was invited to give the Lowell lectures once again. He also made two subsequent visits to the United States in 1852 and 1853.

By this point in his career Lyell had become a prominent man of science. He was elected to membership in the American Philosophical Society in 1842, knighted by the Queen in 1848 and served on the Commission for the Exhibition of 1851. During a second term as president of the Geological Society in 1848-51, Lyell once again criticized the alleged fossil evidence for species change. Some puzzling field observations from Madeira in the Canary Islands came to his attention in 1857, forcing him consider once more the possibility of an evolutionary mechanism behind the development of species. Shortly before this in 1856, Charles Darwin informed Lyell of his own theory of natural selection as the mechanism behind evolution. Despite the implications of Darwin’s ideas for his geology and his view of human life, Lyell encouraged him to publish without delay.

Lyell’s last major work, entitledThe Antiquity of Man, published in 1863, was informed by Darwin’s Origin of Species (1859), as well as new geological evidence that established the existence of early human beings alongside mammoths and other extinct mammals. Lyell now reviewed the evidence for evolution quite favorably, although he only clearly embraced the idea four years later in the tenth edition of thePrinciples (1867-68).

Lyell was active in the British Association for the Advancement of Science in its early years, serving as president for the Bath meeting in 1864. Also, that year he was created a baronet, and in 1866 received the Wollaston medal, the Geological Society’s highest award. Lyell’sElements went through eight editions, and the twelfth edition of thePrinciples was published posthumously in 1875. Lyell died on February 22, 1875 at his London home, preceded two years earlier by his wife Mary. He was buried in Westminster Abbey.