FAMOUS GEOLOGISTS | Lyell

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Jones J (1985) James Hutton’s agricultural research and his life as a farmer. Annals of Science 42: 574–601. McIntyre DB (1997) James Hutton’s Edinburgh: the historical, social and political background. Earth Sciences History 16: 100–157. McIntyre DB and McKirdy A (2001) James Hutton: The Founder of Modern Geology. Edinburgh: National Museums of Scotland (1st edn, 1997). Oldroyd DR (2000) James Hutton’s ‘Theory of the Earth’ (1788). Episodes 23: 196–202.

Playfair J (1805) Biographical account of the life of Dr James Hutton, F.R.S.Edin. Transactions of the Royal Society of Edinburgh 5: 39–99. Sengo¨ r AMC (2001) Is the Present the Key to the Past or the ) Past the Key to the Present? James Hutton and Adam Smith versus Abraham Gottlob Werner and Karl Marx in Interpreting History. Special Paper 355. Boulder: Geological Society of America. Tomkeieff SI (1962) Unconformity – an historical study. Proceedings of the Geologists’ Association 73: 383–417.

Lyell D R Oldroyd, University of New South Wales, Sydney, Australia ß 2005, Elsevier Ltd. All Rights Reserved.

Charles Lyell (Figure 1) was arguably the most important geologist of the nineteenth century, and his Principles of Geology (1st edn, 3 vols, 1830–1833; 11th edn, 1872) was a classic text that exerted much influence on the development of geology, as well as helping to shape the development of Charles Darwin’s thought. Lyell’s other major works were his Elements of Geology (titled Manual of Elementary Geology in some editions) (1st edn, 1838; 6th edn, 1865) and Geological Evidences of the Antiquity of Man (1st edn, 1863; 4th edn, 1873). He also published two books on his travels in North America. Lyell was born into a well-to-do family at Kinnordy House, Forfarshire, Scotland, but much of his youth was spent at the family’s second home in Hampshire (with a more agreeable climate). He attended a private school in Salisbury and then at Midhurst; thereafter he attended Exeter College, Oxford, where he studied mathematics and classics, but also became greatly interested in geology through the lectures of William Buckland, which students could attend as optional additions to their main curriculum. Lyell’s family was considerably interested in natural history, and during his vacations they travelled extensively on the continent. Lyell also made observations on the Kinnordy estate. Even while a student, he was elected Fellow of both the Linnean and Geological Societies. On leaving Oxford, Lyell started to train for the law at an office in London, but found the work uncongenial and complained of problems with his eyesight, and so, having (limited) independent means, he did not continue in this line of work. Rather, consorting with many of the leading geologists of the day, and

travelling widely, he became virtually a full-time gentleman-geologist, being elected to the Royal Society as early as 1826. Two years later when travelling on the Continent and meeting important figures in Paris, etc., he decided to give up legal work altogether. Eventually, he acquired significant income from his geological writings. In 1832, he married Mary Horner, daughter of Leonard Horner, himself a geologist and educationist, who had learned Huttonian theory in Edinburgh. The couple, who had no children, settled in London, where Lyell became established as one of its leading scientists. Buckland’s Oxford lectures were informative and entertaining. He taught the essentials of stratigraphy, and particularly William Smith’s idea that strata could be identified and correlated by their fossil contents (see Famous Geologists: Smith). But Buckland, in the religious atmosphere of Oxford, and trying to show that his science was compatible with the Bible, laid much emphasis on his studies of superficial deposits and cave remains (about which he was an authority) and sought to show that such materials

Figure 1 Charles Lyell (1797–1875).

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could be explained as the result of the Noachian Flood, which in terms of biblical chronology, occurred only a few thousand years ago. Thus, Buckland’s geology, which had sources in the work of Cuvier (see Famous Geologists: Cuvier), could (supposedly) lend material support to theological claims. But such a global flood would have been impossible according to the laws of nature as presently acting, and would be incompatible with geological processes seen at work today. Lyell travelled and thought much during the 1820s; in Scotland he visited such sites as Glen Tilt and Siccar Point (see Famous Geologists: Hutton). Though greatly stimulated by Buckland, he came to reject his idea on the great role ascribed to catastrophic floods, and leaned towards the geology of Hutton, his father-in-law-to-be having attended John Playfair’s ‘Huttonian’ lectures in Edinburgh. Abraham Werner’s Neptunist theories were rejected as being incompatible with the limited solvent power of water and with Hutton’s observations. In Forfarshire (which he mapped in 1824), Lyell saw marls being deposited, or already deposited, in fresh-water lakes fed by springs and associated with shells and plant remains. He knew that in the Paris area Cuvier and Brongniart had found similar fresh-water limestones, which, they thought, had no modern analogues. Thus Lyell’s thinking was turned towards the idea of explaining geological phenomena in terms of presently occurring processes. In Huttonian theory, an immense amount of time was required to make possible the great cycles of geological change that he envisaged. The question of time was one that Lyell, therefore, had to consider. Evidence for the Earth’s great antiquity was produced during Lyell’s journey to Sicily in 1828. He saw the huge still active volcano, Mount Etna, and it was evident that it was made up of successive lava flows. Historical information about recent flows gave an approximate idea of the rate of accumulation of the flows and the build-up of the mountain. The height of the mountain being known, one could thus form an approximate idea of its age. Further, Lyell examined shells in recent-looking strata lying below the lavas. Nearly all were still to be found today in the Mediterranean. So strata and shells of geologically recent appearance were in rocks that were very ancient in human terms, being older than flows from the volcano. (In a subsequent letter to his sister, Lyell offered that on a ‘moderate computation’ the shells might be 100 000 years old.) So if geologically recent rocks were ancient in human terms, rocks lower in the stratigraphic column must be exceedingly ancient. Evidently the Earth was of enormous age. In this argument, Lyell was assuming that the rate of flows

at Etna occurred at approximately equal rates. He was applying the principle that nature was uniform in her operations: what was later dubbed the principle of uniformity. Lyell was a ‘uniformitarian’ with regard to Etna, as he had been with respect to the lake deposits in Forfarshire. Also on his Italian journey of 1828, Lyell visited Pozzuoli on the coast near Naples. There he observed three standing columns of a Roman building, then thought to be an ancient temple. These had marks of the borings of marine organisms half way up, which suggested to Lyell that the land there had fallen below sea level since Roman times, and had subsequently risen; all this having happened without the columns toppling over. From this, Lyell inferred that the level of land was rising or falling in different places, as Hutton had previously proposed. Moreover, the processes were not sudden or catastrophic, but gradual. Following his return to Britain, Lyell began to write his major book, which sought to establish the working methods and procedures of geology. It was to give geology its proper method and fundamental principles: hence its title, Principles of Geology. These may be summed up by the adage (as later stated by Archibald Geikie) that ‘the present is the key to the past’. Also, for Lyell, geological processes were assumed to be ‘gradual’. Hutton’s geology envisaged grand cycles of rock formation, erosion, transport, deposition, consolidation, and subsequent elevation. The rocks of each cycle were not necessarily identical in any given place, and the geologist needed to work out the history of what had happened at each locality. But overall, the earth did not have an historical direction: it did not ‘progress’. Things were much the same in the past and present (humans excepted). Lyell’s views were much the same, but he placed more emphasis on fossils. He supposed that conditions were constantly changing at any given locality from one period to the next, because of the local changes of relative levels of land and sea. Climate could change too, according to whether more high land happened to be near the poles at a given time, or nearer the equator, the former state of affairs producing cooler conditions overall. So some forms would become extinct if they failed to meet the conditions of existence. On this basis, new types of organisms also needed to come into existence from time to time. Lyell presumed that they did so, even though he did not know how this occurred. Further, he assumed that the basic animal types had always been found on the earth. On this view, there was a gradual turnover of species. His model can be represented as shown in Figure 2.

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Figure 2 Diagram illustrative of Lyell’s theory of species change, with ‘random’ creations and extinctions.

According to this model, Lyell assumed that the further back the geologist explored in time, the fewer extant species there would be. In fact, nearly all species before the beginning of the Tertiary in Europe would now be extinct. Further the Tertiary could be subdivided according to its proportions of extant fossils. The subdivisions that Lyell proposed were: . . . .

Newer Pliocene 96% recent fossils Older Pliocene 52% recent fossils Miocene 19% recent fossils Eocene 3% recent fossils

Between the Secondary (later called Mesozoic) rocks and the Tertiary there was a period of nondeposition in Europe, so that Secondary fossils were now virtually all extinct. There had been a complete turnover of forms during the stratigraphic time-gap. Likewise, there was a large time-gap and turnover of forms between the Primary (Palaeozoic) forms and the Secondary types. Moreover, the further back one went through the Secondary epoch, the smaller was the percentage of forms resembling those at the top of the Secondary (i.e., in the Cretaceous); likewise, through the Palaeozoic. Lyell regarded marsupial remains found in Secondary rocks in the Stonesfield Slate near Oxford as vindication of his idea that the major animal types went back into the indefinite past.

That they could not be found in the most ancient rocks was due to the fact that they had been lost by erosion or metamorphism (an important notion that Lyell first explicitly enunciated). All this was compatible with Lyell’s uniformitarianism, but he had no modern empirical warrant for the supposition that new species could somehow come into being. Lyell’s ideas attracted much attention, though most geologists, looking at the stratigraphic record, found it hard to accept that there was no evidence of progress in the fossil record through time. On the other hand, his desire for geology to have its own procedures, with geological processes operating in accordance with the presently observable laws of nature, met with approval, as did his mastery of facts and grasp of palaeontological and stratigraphic detail. He wanted geology to be a science, sui generis, distinct from cosmology. Geologists, he thought, did not need a general ‘theory of the earth’ such as his 18thcentury predecessors had sought to offer (though Lyell’s cyclic geology was in fact fundamentally the Huttonian theory). But Lyell focused on stratigraphy and palaeontology, not ‘hard rocks’ such as granite. In 1831, following the success of Volume I of his Principles, Lyell obtained a chair in geology at King’s College, London, a newly founded Church of England establishment. By then, the putting aside of the Noachian Flood as a geological agent seemed not to concern the authorities, and Lyell’s religious view were considered ‘sound’. However, he only gave lectures there in 1832 and 1833. Ladies were allowed to be present for the first course, but were thought to present an undesirable distraction and their further attendance was terminated. In consequence, the attendance fell sharply, and Lyell decided that he was in part wasting his time there, so he resigned to return to his publishing and life as a gentleman geologist. In this he was eminently successful, continuing his extensive fieldwork, and involvement with the Geological Society and the British Association. Lyell served as President of the Geological Society in 1835–37, and again in 1849–51. Subsequently, he was knighted (1848), was awarded the Royal Society’s Copley Medal in 1858, and served as President of the BA in 1864. Lyell was seriously concerned with French geology. He acknowledged Cuvier’s mastery of palaeontology, but rejected his ‘catastrophist’ theory. Lyell’s Principles did much to counter this doctrine in contemporary Britain. In Paris in 1828, he met with the conchologist and palaeontologist Ge´ rard Deshayes, who assisted him in the identification and stratigraphic placement of the shells he collected that year. Lyell reacted negatively to the tectonic theory of Le´ once E´ lie de Beaumont (which envisaged mountain ranges as having been formed as a result of the

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Earth’s cooling and contraction) and significantly hindered its acceptance in Britain. Most importantly, Lyell gave close attention to the ‘transformist’ (evolutionary) theory of Jean Baptiste Lamarck in Volume II of Principles. Changing conditions cause new needs for organisms. To adjust to changing circumstances, organisms may alter their habits, and consequently their forms. These changes may be transmitted to subsequent generations, producing a gradual transformation of species. The first simple forms of life appeared naturally (without divine action) by spontaneous generation. Such ideas were rejected by Lyell over many pages. His principal objection was that the stratigraphic record did not reveal smooth transitions such as Lamarck’s theory would lead one to expect to find. But there were other objections, such as the inability to produce new species by breeding; and hybrids were sterile. Nevertheless, Lyell devoted much energy to thinking about what the concept of species meant, the ‘laws’ of distribution of species, and the extent to which they could or could not show modification due to different or changing circumstances. The problem of species and speciation was one of the main features of his book, and it set the scene for Darwin’s work, and his seeing his fundamental problem to be ‘the origin of species’ (see Famous Geologists: Darwin). A major problem for geologists in the first half of the nineteenth century was the large quantities of superficial deposits: gravel, tenacious clay containing unsorted rock fragments and fossil remains, and large boulders of rock distant from the nearest ‘solid’ outcrops of rock of that type. Such phenomena were eventually explained by the work of Louis Agassiz and his theory of an Ice Age (see Famous Geologists: Agassiz). In the early nineteenth century, these deposits were ascribed to the Noachian deluge or some like catastrophe, and William Buckland distinguished between ‘diluvium’ (Flood deposits) and ‘alluvium’ (materials deposited by rivers in the normal course of events). It was supposed that a great inundation(s) could have swept over the globe, even depositing the erratic boulders and marine shells loose at the tops of hills or mountains. But according to Agassiz, the better explanation was that there had formerly been a colder climate with the whole of northern Europe once covered by ice, which had transported boulders, ground up the underlying rock, and deposited it, along with river gravels, over the land. The ice also could have scratched the underlying rock and transported shells to hill tops. Agassiz lectured on this to the BA in 1840, and some geologists were converted to his ideas, including Lyell. His general theory was presumed to be capable of accounting for a period of extreme cold,

such as to cause widespread glaciation, if much of the high land at that time happened to be in the polar regions. But Lyell’s conversion was short lived. Agassiz’s theory seemed to take him too far from present analogies or present climatic conditions. So he adopted the theory that came to be called ‘glacial submergence’: there was a period of great cold, but not such as to produce an all-enveloping mass of land-ice. Rather, there was a general fall of land surface, causing marine submergence, accompanied by cooling, causing extension of ice-fields and the transport of boulders by drifting ice-bergs (hence the diluvial deposits are now generally called ‘drift’). During his North American trip of 1845 Lyell saw floating ice in the St Lawrence River, which modern observation seemed to account for the occurrence of erratics satisfactorily in accordance with his methodology. While Lyell later accepted Agassiz’s theory for the Alpine regions he never accepted the general land-ice theory, preferring the glacial submergence model. After Darwin returned from his Beagle voyage in 1836, he and Lyell became close friends, but during the years before the publication of The Origin of Species Darwin mostly kept his emerging transformist ideas to himself. Lyell was opposed to transformism for reasons that he developed back in the 1820s, and like many he was concerned about evolution’s implications for ‘revealed religion’ and social stability. In his Presidential Address to the Geological Society (1851), he spoke against evolutionary ideas. Man, he thought, was a very recent creation, subsequent to the mammoths. However, after Darwin revealed his ideas to Lyell about 1856, he was reluctantly converted and did his best to see the early publication of Darwin’s ideas in 1858. In his The Antiquity of Man (1863), Lyell set forth ideas on transformism and stated his acceptance of the Darwinian theory of evolution by natural selection (though he represented it as a ‘modification’ of Lamarck’s doctrine). In the 1850s, Lyell had devoted a considerable amount of travel and fieldwork to the study of ancient humans, which was consistent with his general interest in the younger parts of the stratigraphic column. By that time, considerable numbers of cave deposits and flint implements had been discovered, as well as some human-like remains, notably the Neanderthal skull, found near Dusseldorf in 1857. This seemed, according to Thomas Henry Huxley’s description, which Lyell quoted, to be intermediate between that of a modern human and a chimpanzee’s. But Lyell cautiously (and rightly) stated that ‘‘it is at present to too exceptional, and its age too uncertain, to warrant us in relying on its abnormal and ape-like characters, as bearing on the question whether the farther back we trace Man into the past, the more

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we shall find him approach in bodily conformation to those species of the anthropoid quadrumana which are most akin to him in structure’’ (Antiquity, p. 375). Lyell also reported on the recently discovered Archaeopteryx, which might seem to be a missing link, but he also deferred to the anatomist Richard Owen’s opinion that it was actually a bird. Thus, Lyell supported Darwin’s evolutionism in a way that was valuable to its acceptance. But at the same time he did not push all the evidence to what we might regard as its logical conclusion. On reading Lyell’s works, one is struck by his mastery of exposition and his command of the literature, especially in stratigraphy. His influence was very great, both in his own day and subsequently. There is, however, ambiguity in the concept of ‘uniformitarianism’ (gradualism, steady-statism, naturalism, and ‘actualism’ – or the idea that modern, actually observable, processes should be used to provide geological explanations). Lyell held to all these positions. Modern geologists commonly make obeisance to uniformitarianism, without making the foregoing distinctions. Modern geology does not necessarily adhere to any of them, except in its rhetoric; for Lyell convinced people that his approach was the right one to adopt for geology to be regarded as a science.

See Also Famous Geologists: Agassiz; Cuvier; Darwin; Hutton; Smith. History of Geology From 1780 To 1835. History of Geology From 1835 To 1900.

Further Reading Gould SJ (1987) Charles Lyell, historian of time’s cycle. In: Gould SJ (ed.) Time’s Arrow Time’s Cycle: Myth and Metaphor in the Discovery of Geological Time, pp. 99–179. Cambridge (Mass) and London: Harvard University Press. Hooykaas R (1963) Natural Law and Divine Miracle: The Principle of Uniformity in Geology, Biology and Theology. Leiden: EJ Brill. Lyell C (1997) Principles of Geology edited with an introduction by James A. Secord. London, New York, Ringwood, Toronto and Auckland: Penguin Books. British Society for the History of Science (1976) The British Journal for the History of Science: Lyell Centenary Issue 9(2). Rudwick MJS (1969) Lyell on Etna, and the antiquity of the Earth. In: Schneer CJ (ed.) Toward a History of Geology, pp. 288–304. Cambridge (Mass) and London: The M.I.T. Press. Rudwick MJS (1971) Uniformity and progression: reflections on the structure of geological theory in the age of Lyell. In: Roller DHD (ed.) Perspectives in the History of Science and Technology, pp. 209–227. Norman: University of Oklahoma Press. Rudwick MJS (1978) Charles Lyell’s dream of a statistical palaeontology. Palaeontology 21: 225–244. Rudwick MJS (1990) ‘‘Introduction,’’ Principles of Geology, First Edition [in Facsimile] Volume I Charles Lyell, pp. vii–lviii. Chicago: University of Chicago Press. Wilson LG (1972) Charles Lyell: The Years to 1841. New Haven: Yale University Press. Wilson LG (1998) Lyell in America Transatlantic Geology, 1841–1853. Baltimore and London: The Johns Hopkins University Press.

Murchison D R Oldroyd, University of New South Wales, Sydney, Australia ß 2005, Elsevier Ltd. All Rights Reserved.

Roderick Murchison (Figure 1) was the eldest son of a wealthy Scottish landowner at Tarradale estate, Ross-shire. Though born in Scotland, and always emphasizing his Scottish ancestry, he spent most of his career in England and spoke with an English accent. Following his father’s death and mother’s remarriage, Roderick was sent to school at Durham, aged 7 years, soon forming the ambition to be a soldier. At 13 years old, he attended the military college at Great Marlow where his training gave him a good ‘eye for country’. He was soon involved

in the ‘Peninsula War’ in Portugal, fighting at the Battle of Vimieira, aged only 16 years. From this victory, his unit moved into Spain where things went badly for the British army in winter conditions, with forced marches, defeat in the Battle of Coruna, and withdrawal in disarray. After a spell in Sicily, Murchison was posted to Ireland, where he led a dissolute and expensive life, and later likewise in London as a half-pay captain. With the end of the wars, he was fortunate to meet a general’s daughter, Charlotte Hugonin, 3 years his senior, and they were married in 1816. They then took a leisurely tour through France, Switzerland, and Italy, and under his wife’s influence his self-education began, learning French and Italian, visiting museums and galleries and some scientists and scientific institutions.