Geology,Mineralogy and Time in John Walker's University of Edinburgh Natural History Lectures (1779–1803)

To date, the only published edition of Walker's lectures is Lectures in geology — Including hydrography, mineralogy, and meteorology with an introduction to biology by John Walker , ed. by Scott H. W. (Chicago, 1966). True to the title, it contains a relatively complete representation of Walker's hydrography, meteorology and geology lectures as preserved in transcribed notebooks housed in the Edinburgh University Library. For this reason, I refer to Scott's edition when referencing these lectures. Scott's edition does not, however, contain Walker's mineralogy lectures. It merely contains one lecture that Walker gave as a bibliographical orientation to mineralogy. This is because Scott was principally interested in Walker's role as a forerunner to modern geology and did not realize how much Walker's chemical mineralogy shaped his conception of geology. All references that I make to Walker's mineralogy and zoology lectures will therefore refer to lecture manuscripts in the Special Collections of the Edinburgh University Library (EUL).

“A general view of its literary history”, Notes and lectures on Natural History vol. I (1789), EUL Gen 50, ff. 40–41.

Walker John , “An account of a new medicinal well, lately discovered in Moffat”, Philosophical transactions of the Royal Society, l (1758), 117–47.

John , second Earl of Hopetoun (1704–81) and his son James (1741–1816), who was styled Lord Hope in 1766. Eddy M. D. , “James Hope”, New dictionary of national biography (Oxford, forthcoming).

Formed to administer the confiscated lands of Scottish nobles who supported the 1745 Jacobite Rebellion.

Walker John , “Dr. John Walker's report to the Assembly 1765, concerning the state of the Highlands and Islands”, Scots magazine, xxviii (1766), 680–9. Walker John , “Dr. John Walker's report concerning the state of the Highlands and Islands, to the General Assembly 1772”, Scots magazine, xxxiv (1772), 288–93.

See “Mineralogical journal from Edinburgh to Elliock…” (c. 1765) and “Mineralogical journal from Edinburgh to London” (c. 1772) in his Essays on Natural History and Rural Economy, ed. by Stewart Charles (Edinburgh, 1808).

Shapin S. , “Property, patronage, and the politics of science: The founding of the Royal Society of Edinburgh”, The British journal for the history of science, vii (1974), 1–41.

Greville R. K. , Algæ Britanicæ, or descriptions of the marine and other inarticulated plants of the British Isles, belonging to Order Algæ; with plates illustrative of the genera (Edinburgh, 1830). Taylor G. , “John Walker, D.D., F.R.S.E. 1731–1803: Notable Scottish naturalist”, Transactions of the Botanical Society of Edinburgh, xxviii (1959), 180–203.

Withers C. W. J. , “A neglected Scottish agriculturalist: The ‘Georgical Lectures’ and the agricultural writings of Rev. Dr. John Walker (1731–1803)”, Agricultural history review, xxxiii (1985), 132–43.

See Scott's “Introduction”, in Lectures … by John Walker (ref. 1). Ritchie J. , “Natural history and the emergence of geology in the Scottish universities”, Transactions of the Edinburgh Geological Society, xv (1952), 297–316.

See EUL DC.2.19 and Glasgow University Library, Special Collections, GB 247 Gen. 1061.

29 October 1765, John Ellis to Linnaeus, in Smith J. E. , A selection of correspondence of Linnaeus and other naturalists (New York, 1978), 180; originally published in 1821. 29 October 1765, William Walison to Richard Pultney, National Library of Scotland (NLS) Acc. 9533 No. 314.

Hopetoun Lords Bute Mure Buchan Daer Cathcart . He also corresponded with Sir John Pringle and Sir George Clerk-Maxwell.

Particularly Lords Kames, Hailes, Gardenstone and Woodhouselee.

Darwin Robert Waring Beddoes Thomas Smith James Edward Brown Robert Jameson Robert Hall James Sir Playfair John . Listed in Index to students in Natural History class lists 1782–1800, EUL Special Collections Reading Room.

21 April 1764, Thomas Pennant to William Cullen: “I take the liberty of recommending to Mr. Walker a thorough Attention to the Zoology of the Western Isles…”, EUL La.III.352/1, ff. 9–10.

29 October 1765, John Ellis to Linnaeus.

Including Sir Joseph Banks, Anne Blackburne, Carl Peter Thunberg, F. W. P. Fabricius, Dr Richard Pulteney, Dr Maxwell Garthshore and Dr William Wright.

24 January 1784, Walker to Robert Liston, National Library of Scotland (NLS) MS 5540, f. 34, and EUL SC MS La.III.352/3. Walker was also in contact with Dr John Rogerson, physician to the Russian court in St Petersburg, and Lord Cathcart, British Ambassador to Russia.

The philosophical foundations and the spread of Linnaeus's system are detailed in Stafleu F. , Linnaeus and the Linnaeans: The spreading of their ideas in systematic botany, 1735–1789 (Utrecht, 1971); Desmond Ray , Kew: The history of the Royal Botanical Gardens (London, 1995); Gage A. T. Stearn W. T. , A bicentenary history of the Linnean Society of London (London, 1988).

Several of these letters can be found in EUL, La.III.252/1. Some of these have been printed in Scott's edition of Walker's lectures (ref. 1). Also see Smith's A selection of the correspondence of Linnaeus (ref. 13), Linnaeus to Ellis John , 29 October 1765.

Natural History lectures (1789), EUL Gen 50, ff. 113–24; Natural History lectures (1790), EUL DC.2.24, ff. 236–54 and continued in EUL DC.2.25, f. 1; 1797 Natural History lectures , EUL Gen 705.D, ff. 130–62. Scott includes a copy of it taken from DC.2.18, which is undated. To judge from several internal references, it was probably written in the mid- to later 1790s.

His Essays on Natural History and Rural Economy (ref. 7) and in his miscellaneous manuscript lectures, essays and notes (EUL DC. 1.58 and DC. 1.59) were firmly based on his thirty years of natural history fieldwork, Walker taking care to note the properties of the animals, plants, minerals and antiquities in the area that he is exploring. His mineralogical sections in several of his Essays contain tests using vitriolic acid, aqua fortis, muriatic acid, volatile alkali and fire to determine a mineral's chemical character. For example, see his “History of the Island of Icolumbkil”, 111–218.

Epistemic questions of believability and the value of a gentleman's word within scientific discourse are raised in S. Shapin's A social history of truth: Civility and science in seventeenth-century England (Chicago, 1995). The issue of personal testimony became a little more complicated in the Scottish scene during the mid-eighteenth century, primarily as a result of the debates between Hume and Reid. On the whole, Walker accepts natural history testimony if it conforms with what he or his colleges have personally observed or if it agrees with other authors whose observations have been reliable in the past. For the general context that shaped the epistemic value of testimony during Walker's time, see Shapin S. , “The audience for science in eighteenth-century Edinburgh”, History of science, xxii (1974), 95–121, and Golinski J. , Science as public culture: Chemistry and Enlightenment Britain, 1760–1820 (Cambridge, 1992).

“IMPERIUM NATURÆ or EMPIRE OF NATURE, vizt. The Fossil, Vegetable and Animal Kingdoms”. This lecture is housed in EUL DC. 2–18 and is printed in Lectures … by John Walker (ref. 1), 214–22. All quotations in the paragraph are taken from the former source. Walker uses the word ‘fossil’ in its Latin sense, which generally refers to anything dug out of the ground.

Linnaeus's Aristotelian foundations are discussed in detail in Stafleu, especially in chaps. 2 to 4.

This was the approach of John Ray and J. P Tournefort. Late eighteenth-century French taxonomists thought the natural method was possible and therefore more readily accepted Jussieu's 1789 Genera plantarum.

“[M]ost of the methodical arrangement of the three kingdoms is of this kind, as in Linnæus' Species Plantarum; and in it he says, that Salix has but two Stamina, whereas some have 3 or 4 but they are in other respects genuine Salices.” Walker , “IMPERIUM NATURE or EMPIRE OF NATURE”, Lectures … by John Walker (ref. 1), 222.

Ibid., 220.

“On the Subject of Botany, we proposed to consider, Vegetable Anatomy, Vegetable Physiology, and Vegetable Economy, but as this Subject has a different Course allotted to it, we shall not treat it here.” Epitome of Natural History vol. IX (1797), EUL Gen 711.D, f. 121.

The scope of this essay restricts me from pursuing Walker's zoological classification system: “General Division of the Animal Kingdom. That is the foundation of the Linnæan System of Zoology. Linnæus very properly altered the arrangement of the Animal Kingdom, and in the latter edition of Systema Naturae he has founded the division of animals more on their internal structure than their external form, and is therefore the most proper writer to follow in this part of Zoology.” Lectures on Natural History vol. IV (1790s), EUL DC.2.19, ff. 117–18. For an example of Walker's mammal classification see: Mammalia Scotica, written c. 1764–74, printed in Essays on Natural History and Rural Economy (ref. 7), 471–533.

Lectures … by John Walker (ref. 1), “Mineralogy Lecture”, 228.

Laudan R. , From mineralogy to geology: The foundations of a science 1650–1830 (London, 1987). See chap. 4, “The botanical model rejected”. Oldroyd D. , Thinking about the earth: A history of ideas in geology (London, 1996), chap. 3, “The beginnings of geological science: Detachment from cosmogony and mineralogy”. Abraham Gottlieb Werner (1749–1817), Professor of Mining and Mineralogy at the Mining Academy of Freiberg in Saxony, also used chemistry for his mineralogical investigations. However, he is not mentioned by Walker.

The geological contours of this context are outlined in: Bowler P. , Evolution: The history of an idea (London, 1989); Rudwick M. J. S. , “The shape and meaning of earth history”, in Lindberg D. C. Numbers R. L. (eds), God and nature: Historical essays on the encounter between Christianity and science (London, 1986), 296–321; Brooke J. H. , Science and religion: Some historical perspectives (Cambridge, 1993), especially chap. 7, “Visions of the past: Religious belief and the historical sciences”.

Wood P. B. , “The natural history of man in the Scottish Enlightenment”, History of science, xxviii (1990), 89–123, p. 102. These teleological proclivities were often heavily influenced by the ‘ordered’ conception of nature as promoted by the sixteenth-century theologian and reformer Jean Calvin in his Institutes of the Christian religion. See Institutio christianae religionis, ed. by McNeill J. T. (London, 1961).

Natural History lectures (1789), “A general view of its literary history”, EUL Gen. 50, f. 55.

Occasional remarks by the Revd. Dr. Walker Prof, of Natural History at Edinburgh, EUL DC.2.40, f. 118.

Donovan A. L. , Philosophical chemistry in the Scottish Enlightenment: The doctrines and discoveries of William Cullen and Joseph Black (Edinburgh, 1975), 53–62. For Locke's usage of natural history and philosophy, see Carey D. , “Locke, travel literature, and the natural history of man”, The seventeenth century, ix (1996), 259–80. For the general emergence of empirical geology based on close examination of strata, see Porter Roy , “George Hoggart Toulmin's theory of man and the earth in the light of the development of British geology”, Annals of science, xxxv (1978), 339–52.

For related discussions see: Wood P. B. , “The science of man”, in Jardine N. Secord J. A. Spary E. C. (eds), Cultures of natural history (Cambridge, 1996), 197–210, and Wood's “Introduction” in Wood P. B. (ed.), Thomas Reid on the animate creation (Edinburgh, 1995); Sloan's P. R. “Buffon, German biology, and the historical interpretation of species”, The British journal for the history of science, xxii (1979), 109–53, and his “John Locke, John Ray, and the problem of the natural system”, Journal of the history of biology, v (1972), 1–53.

Lectures … by John Walker (ref. 1), “IMPERIUM NATURÆ or EMPIRE OF NATURE”, 220.

Ibid., “Introduction Lecture”, 18, 20, 21.

Ibid. , “Hydrography Lectures”, 150.

Ibid., “Meteorology Lectures”, 71.

Ibid., “Meteorology Lectures”, 113.

Ibid., “Geology Lectures”, 180.

National Archives of Scotland (NAS) GD24/1/571/164–170. Printed in Alexander Fraser Tytler, Memoirs of the life and writings of the Honourable Henry Home of Kames … Vols. 1 & 2 (Edinburgh, 1807), Appendix No. II, 56–66.

Even though Buffon sought to base Histoire naturelle upon the known empirical ‘facts’, his theoretical sections were generally subject to much criticism within the Scottish context. Wood P. B. , “Buffon's reception in Scotland: The Aberdeen connection”, Annals of science, xliv (1987), 169–90.

Lectures … by John Walker (ref. 1), “Meteorology Lectures”, 116. Also see Walker's treatment of Buffon in when he discusses subterranean heat in his “Geology Lectures”, 200–1.

P. R. Sloan addresses Buffon's epistemology in op. cit. (ref. 40). See also his “The Buffon–Linnaeus controversy”, Isis, lxvii (1976), 356–75, and “Buffon studies today”, History of science, xxxii (1994), 469–77.

Lectures … by John Walker (ref. 1), “Geology Lectures”, 172. For Buffon's comments on this topic see Proofs Article IX, “Of the inequalities upon the earth's surface” in his Natural history.

This was generally how Buffon's work was viewed by the “new generation of naturalists” during the last decades of the eighteenth century. Rudwick M. J. S. , The meaning of fossils: Episodes in the history of paleontology (London, 1972), 93–95.

Lectures on Natural History, vol. IV (1790s), EUL DC.2.19, f. 3.

Sciagraphia regni mineralis (1782) enjoyed a wider circulation in Britain and laid the foundation for Bergman's final mineralogical system detailed in Meditationes de systemate fossilium naturali (1784). De tubo feruminatora (1779) gives a full account of how to use a blowpipe and De minerarum dicomasia humido (1780) details methods for using water in tests for chemical composition.

Originally written as articles in the Swedish journal Kungliga Vetenskapsakademiens Handligar during the 1750s. On the basis of these, Cronstedt published FörsoUk til mineralogie, eller mineralrikets upställning (Stockholm, 1758), which was translated into German as Versuch einer neuen Mineralogie (Copenhagen, 1760) and then again with additions by Werner A. G. (Leipzig, 1780). It was translated into English as An essay towards a system of mineralogy in 1770. On Cronstedt's system, see Oldroyd D. R. , “Notes and correspondence: A note on the status of A. F. Cronstedt's simple earths and his analytical methods”, Isis, lxv (1974), 506–12.

Laudan , op. cit. (ref. 34), 62–69. For a detailed view of Bergman's chemical testing methods see Oldroyd D. R. , “Some eighteenth century methods for the chemical analysis of minerals”, Journal of chemical education, l (1973), 337–40.

For a background of diluvialism, see Huggett R. , Cataclysms and earth history: The development of diluvialism (Oxford, 1989). Diluvialism was very influential during the later eighteenth century, particularly because of its promotion by Freiberg's A. G. Werner.

All quotations from Walker in this paragraph are taken from his “Hydrography Lectures”, Lectures … by John Walker (ref. 1), 128–30.

Halley Edmond , “A short account of the cause of saltness of the ocean, and of several lakes that emit no rivers; with a proposal, by help thereof, to discover the age of the world”, Philosophical transactions, xxix (1715), 296–300. As with most of his references, Walker cites only Halley's argument and not the printed source. This work is briefly addressed in Rudwick , op. cit. (ref. 52), 93. This system would be used again by John Joly in 1899.

Halley , op. cit. (ref. 59), 300, 299. Halley's article was actually written to clear himself of allegations that accused him of denying the finite age of the world. Even though he says that further evidence might demonstrate the earth to be “older than many have hitherto imagined”, he candidly admits the argument is of no practical use because it requires “great Intervals of time to come to our Conclusion”. This is treated in Cook A. , Edmond Halley: Charting the heavens and the seas (Oxford, 1998).

Regarding the salinity test, William Smellie's 1771 Encyclopædia Britannica states: “With regard to the saltness of the sea-water, it is very rationally judged to arise from great multitudes both of mines and mountains of salt, dispersed here and there in the depths of the sea. Dr. Halley supposes that it is probable the greatest part of the sea-salt, and of all salt lakes … is derived from the water of the rivers which they receive.” Encyclopedæ Britannica; or, A dictionary of arts and sciences, compiled upon a new plan … (by a society of gentlemen in Scotland), iii (Edinburgh, 1771), 572. Citing Halley, Buffon asserts the same positions in his “Of rivers” chapter in Natural history (1828), 71.

Lectures on Natural History (1790), EUL DC.2.25, ff. 22–23.

Lectures on Natural History (1790), EUL DC.2.25, f. 23.

See Appendix.

Lyell C. , Principles of geology or The modern changes of the earth and its inhabitants (London, 1875), 58–59. Porter R. , The making of geology: Earth science in Britain 1660–1815 (Cambridge, 1977), 160–5. Geikie A. , The founders of geology (London, 1905), 194–5.

Walker often uses the words ‘primary’ and ‘primitive’ interchangeably. He states that primary mountains mainly consisted of quartz, feldspar, jasper, soap-rock, lapis olaris (soap stone), amianthus (white asbestos), asbestos, slate, touch stone (black jasper), porphyry, serpentine, granite, whin rock and basalts — All of these being composed of schorl and mica. Lectures … by John Walker (ref. 1), “Geology Lectures”, 174.

Walker states (ibid.) that secondary mountains mainly consist of limestone, shell marle, marble, Portland stone, alabaster, gypsum, ironstone, sandstone, mill stone and coal.

Walker John . Letter to Colonel Dirom, Quarter Master of Scotland, on the discovery of coal (Edinburgh, 1800), 4.

Lectures … by John Walker (ref. 1), “Hydrography Lectures”, 126–8.

Ibid., “Geology Lectures”, 176.

Ibid., “Geology Lectures”, 173. The italics are my own.

Ibid., “Geology Lectures”, 170.

Ibid., “Geology Lectures”, 175.

Ibid., “Geology Lectures”, 176. Also see William Smellie's similar definition in the “strata” entry in the Encyclopaedia Britannica, iii (ref. 61), 636. Part of it states: “The time when these several strata were laid, was doubtless at the beginning of the world; unless, with some great naturalists, as Steno, Dr. Woodward, &c. we suppose the globe of the earth to have been dissolved by the deluge.”.

Walker hints at this in the end of his Hydrography Lectures, “Every part [of the globe] is thus supply'd with water, and if there are any little inequalities they serve only to shew the great wisdom [with which] the whole is conducted. There we may behold the footsteps of that divine power which every where pervades the works of nature.” Lectures … by John Walker (ref. 1), “Hydrography Lectures”, 164. Compare with Smellie's translation of Buffon's “On nature” chapter in Natural history: “Omnipotent God! whose presence supports Nature, and maintains harmony among the laws of the universe.” The entire chapter is replete with such references.

Lectures … by John Walker (ref. 1), “Geology Lectures”, 173–4. Buffon maintained a similar opinion in Article VII, “Of the formation of strata, or beds, in the earth” in his Natural history: “The vapours exhaled from the earth produce rain, dews, thunder, lightning, and other meteors. The vapours, therefore, are mixed with particles of water, air, sulphur, earth &c…. The purest rain-water deposits a quantity of this mud; and, when a quantity of dew is collected, and allowed to corrupt, it produces a greater proportional quantity of mud, which is fat, unctuous, and of a reddish colour.” Buffon , op. cit. (ref. 61), 44.

Lectures … by John Walker (ref. 1), “Geological Lectures”, 156. Richard Kirwan used a similar argument against Hutton's theory. Kirwan Richard , Geological essays (London, 1799).

Lectures … by John Walker (ref. 1), “Geology Lectures”, 175. Walker uses the word ‘æra’ to connote large spans of human time such as the Roman era or the modern era. For instance, “A body which was there dug out of the peat moss had on its feet antique sandals, which plainly shew'd it to be of the Roman æra”, 199.

“There is another remarkable and well established distinction between primitive and secondary mountains, which is that the primitive contain no extraneous fossils.” Lectures … by John Walker (ref. 1), “Geology Lectures”, 175.

This was no doubt because of time constraints. In his mineralogy lectures, Walker gives a significant amount of attention to the specific minerals that compose secondary strata.

Lectures on Natural History, vol. IV (1790s), EUL DC.2.19.

See his comments on the former presence of the elk in Scotland and the Scotch pine in England. Lectures … by John Walker (ref. 1), “Geology Lectures”, 196–8.

Because of the connection often made between earthquakes and volcanoes, a significant amount of attention was given to this subject after the Lisbon earthquake in 1755. It served as a commonplace for most natural historians when discussing subterranean issues. For the immediate reaction to the Lisbon earthquake, see the many letters printed in vol. xlix (1755) of the Royal Society's Philosophical transactions.

Hamilton William , Observations on Mount Vesuvius, Mount Etna and other volcanoes, in a series of lectures addressed to the Royal Society of London… (London, 1772). Hamilton was the British envoy, in Naples, to the court of King Ferdinand IV from 1764 to 1800.

Lectures … by John Walker (ref. 1), “Geology Lectures”, 176.

For instance, see Mitchell John , “Conjectures concerning the cause, and observations upon the phænomena of earthquakes”, Philosophical transactions of the Royal Society, li (1760), 566–634.

“The Basaltes have been accounted a Volcanic Production, but of this we have not any satisfactory proof whatsoever.” Epitome of Natural History 1797 vol. VI, EUL Gen. 708D, f. 93. Walker held that the “most possible opinion” was that basalts were indurated schistic earth that were divided into columns by mechanical means. Lectures on Natural History 1790 vol. IV, EUL DC.2.26, f. 58.

Specifically, its situs is listed as stratis primitivis in his 1797 lectures. Epitome of Natural History 1797 vol. VI, EUL Gen. 708D, f. 87.

Strange John , “An account of a curious Giant's Causeway, or group of angular columns, newly discovered in the Euganean Hills, near Padua, in Italy”, Philosophical transactions of the Royal Society, lxv (1775), 418–23. Strange John , “An account of two Giant's Causeways, or groups of concretions, in the Venetian state in Italy”, Philosophical transactions of the Royal Society, lxv (1775), 5–47. Raspe R. E. , “A letter from Mr. R. E. Raspe, F.R.S. to Mr. Maty, M.D. Sec. R.S. containing a short account of some basalt hills in Hassia”, Philosophical transactions of the Royal Society, lxi (1771), 580–3.

Notably, he opposed the view that Gaelic was not a written language. 22 March 1775, Donald McNicol [of Lismore] to Walker, EUL La.III.352/1, ff. 40–43. He also was interested in the language of Ireland: EUL DC. 1.59, f. 63.

For instance, in a letter to Lady Kames regarding his 1771 Hebrides expedition, dated 29 February 1772, Walker takes care to highlight several of the mythological sites he visited, some of the more notable being: Fingal's residence (he gives the etymology of the Gaelic name Selma), the Sunny Spot of Darthule, and Hill of the Fingalians in Glencoe. He even goes on to reference MacPherson's Ossian poem. NAS GD 24/1/496–503A/629–630.

Lectures on Natural History vol. III, EUL DC.2.19, f. 263, and Lectures on Natural History vol. IV (1790), EUL DC.2.26, f. 56.

Lectures … by John Walker (ref. 1), “Geology Lectures”, 182.

Lectures on Natural History vol. III, EUL DC.2.20, ff. 4–6.

For his discussion of peat moss, see: Lectures … by John Walker (ref. 1), “Geology Lectures”, 189–99.

Ibid., “Geology Lectures”, 179–80.

Ibid., “Geology Lectures”, 177–9.

Ibid., “Hydrography Lectures”, 157–60.

Walker's discussion of other tertiary strata such as Stapple and Sea Sand also demonstrate a similar atemporal conception of time. Lectures … by John Walker (ref. 1), “Geology Lectures”, 189–90 and 192–3.

Walker John , “An account of the irruption of Solway Moss”, Philosophical transactions of the Royal Society, lxii (1772), 123–27; “An essay on peat, containing an account of its origin, of its chymical principles and general properties”, Prize essays and transactions of the Highland Society of Scotland, ii (1803), 1–137.

Lectures … by John Walker (ref. 1), “Geology Lectures”, 197.

Walker also discusses peat in a shell marle essay. It seems he believed that marle formed on top of peat was made from shells, but marle formed underneath was not. Thus, the time element involved in making shell marle falls within the perimeters of peat moss development outlined in his lectures. See “The history of shell marle” (c. 1770), in Essays on Natural History and Rural Economy (ref. 7). For unknown reasons, Scott includes parts of this essay in his 1966 edition of Walker's lectures even though it was published posthumously and even though it was as an essay, not a lecture. Walker briefly addresses shell marle in his posthumous An economic history of the Hebrides and Highlands of Scotland (London, 1812), 141–2.

There were many biblically based ages of the world floating around eighteenth-century Britain. Generally, calculations based upon the Vulgate provided a 6000-year age, while calculations based on the Septuagint provided a 7000-year age. The 6000-year time-frame, as promoted by Ussher, became much more popular in the nineteenth century after it had been included in the seventeenth edition of the King James Version of the Bible. J. Fuller, “Before the hills in order stood: The beginning of the geology of time in England”, a paper given on 29 June 2000 in London at the conference entitled “Celebrating the age of the earth: A symposium on geological time hosted by the History of Geology Group”.

Lectures on Natural History (1790), EUL DC.2.25, f. 62. Also listed in Lecture on Natural History vol. III (1790s), EUL DC.2.19, f. 3. This classification is slightly different from the one included in Scott's edition (page 230). Scott used the Schediasma fossilium, which was published in 1781. By 1790 Walker had eliminated the Fusoria class and had added Ponderosa and Amandina classes.

It is sometimes very easy to confuse Walker's different usages of the word ‘Earth’ (a common problem for many eighteenth-century mineralogy works). Usually when Walker uses this word on its own, he means Terræ, or the first class of Fossils.