Research support for this paper has come from three sources, NEH, NSF and the University of Missouri at Kansas City. In addition, I should like to thank the editor of this journal for his helpful suggestions.

¹ Thomas S. Kuhn's work, which is more familiar to historians of science than that of Lakatos or Laudan, is found in his The structure of scientific revolutions, 2nd edn., enlarged, Chicago, 1970.Google Scholar The most complete statement of Lakatos' position may be found in Lakatos, Imré and Musgrave, Alan (eds.) Criticism and the growth of knowledge, London, 1970.CrossRefGoogle ScholarLaudan, L.'s position is put forth in his Progress and its problems, Berkeley, 1977.Google Scholar Although their views differ in many significant respects, the question of which of the three best accounts for the case study developed in this paper is not considered. It neither follows that I think they each could equally account for this episode in the development of modern geological theory, or that they actually do equally account for it. To argue that one of them would provide a better account than the others, however, would require extensive treatment of the overall development of modern geological theory of which this case study is only a part.

² For convenience I shall employ Lakatos' terminology rather than that of Kuhn or Laudan.

³ The first edition of Die Entstehmg der Kontinente und Ozeane appeared in 1915, and was followed by four more editions in 1920, 1922, (revised 4th edition of 1929), and 1936. All quotations from this work are from a 1966 English translation of the 1929 edition, Wegener, A., The origin of continents and oceans, New York, 1966.Google Scholar I am using the fourth edition because it is the most complete and it includes a number of comments by Wegener on the initial reception of his drift hypothesis.

⁴ Wegener, A., The origin of continents and oceans (tr. by Skerl, J.), London, 1924Google Scholar. This edition included a foreword by John Evans who was then die president of the Geological Society of London.

⁵ See, for example, either Hallam, A., A revolution in the earth Sciences, Oxford, 1973Google Scholar; or Marvin, U., Continental drift, the evolution of a concept, Washington, 1973.Google Scholar Both works contain excellent accounts of die development of drift theory and its eventual inclusion into plate tectonics.

⁶ van der Gracht, W. van Waterschoot (ed.), Theory of continental drift: a symposium on the origin and movement of land masses both inter-continental and intra-continental, as proposed by Alfred Wegener, Tulsa, 1928, pp. 104–105.Google Scholar Besides editing the selections from this 1926 symposium for publication in 1928, van der Gracht included two papers of his own.

⁷ Lake, P., ‘Wegener's displacement theory’, Geological magazine, 1922, 59, 338–46 (338).CrossRefGoogle Scholar

⁸ Lake, , op. cit. (7), p. 344.Google Scholar

⁹ Ibid. p. 346.

¹⁰ Gregory, J., ‘Continental drift’, Nature, 1925, 115, 255–7.CrossRefGoogle Scholar

¹¹ Ibid., p. 255.

¹² Wright, W. D., ‘The Wegenerian hypothesis’, Nature, 1923, 111, 30–1.CrossRefGoogle Scholar

¹³ van der Gracht, , op. cit. (6).Google Scholar

¹⁴ Ibid., pp. 104–44.

¹⁵ See Marvin, , op. cit. (5), p. 149Google Scholar, for a comparison between Wegener's fit and Carey's 1958 fit. The difference is not very great.

¹⁶ Du Toit, A., Our wandering continents, London, 1937.Google Scholar

¹⁷ van der Gracht, , op. cit. (6), p. 216.Google Scholar

¹⁸ Coleman, A., ‘Permo-carboniferous glaciation and the Wegener hypothesis’, Nature, 1925, 115, 602.CrossRefGoogle Scholar

¹⁹ Holmes, incidentally, considered the reconstruction of the Carboniferous glaciations ‘to be the basis of Wegener's most powerful argument’ for continental drift: Holmes, A., ‘A review of the continental drift hypothesis’, Mineralogical magazine, 1929, 40, 205–9, 286–8, 340–7 (340).Google Scholar

²⁰ Van der Gracht, , op. cit. (6), p. 1.Google Scholar

²¹ Wegener, , op. cit. (3), p. 167.Google Scholar

²² Even H. Hess, responsible for the concept of seafloor spreading, and R. Dietz, who coined the expression ‘seafloor spreading’, considered the ‘mechanism’ problem to be one of the major problems faced by supporters of Drift. Moreover, there is a striking similarity between seafloor spreading and Holmes’ seafloor thinning—a similarity which has been pointed out by Hess and others. But as Hess has emphasized, there are significant differences. Both eliminate any actual ploughing of continental material through the seafloor, but, on Hess' view, new seafloor is created, while according to Holmes, existing seafloor is stretched. Cf. Dietz, R., ‘Continent and ocean basin evolution by spreading of the sea floor’, Nature, 1961, 190, 854–7.CrossRefGoogle Scholar

²³ Wegener, , op. cit. (3), p. 175.Google Scholar

²⁴ Lake, , op. cit. (7), p. 339.Google Scholar

²⁵ Ibid., p. 339.

²⁶ Jeffreys, H., The earth, London, 1924, p. 261.Google Scholar

²⁷ My italics. Wright, , op. cit. (12), p. 31.Google Scholar

²⁸ van der Gracht, , op. cit. (6), pp. 119–200.Google Scholar

²⁹ Wegener, , op. cit. (3), p. 60.Google Scholar

³⁰ Joly began investigating the interplay between radioactivity and geology as early as 1908. Cf. Joly, J., ‘Uranium and geology’, Annual report of the Smithsonian Institution, 1908, pp. 355–84.Google ScholarPubMed

³¹ Joly, J., ‘The movements of the earth's surface crust’, Philosophical magazine, 1923, 45, 1167–88 (1188).Google Scholar

³² Daly, R., Our mobile earth, New York, 1926.Google Scholar

³³ Cf. Marvin, , op. cit. (5), 98.Google Scholar

³⁴ Cf. Dunham, K. L., ‘Arthur Holmes’, in Biographical memoirs of Fellows of the Royal Society, 1966, 12, 291–310.Google Scholar

³⁵ Holmes, A., The age of the earth, London, 1913.Google Scholar

³⁶ Holmes, A., ‘Radioactivity and the earth's thermal history. Pt. I. ‘The concentration of the ratioactive elements in the earth's crust’, Geological magazine, 1915, 2, 60–71.CrossRefGoogle Scholar Pt. II. ‘Radioactivity and the earth as a cooling body’, ibid., 1915, 2, 102–12. Pt. III. ‘Radioactivity and isostasy’, ibid., 1916, 4, 264–74. Pt. IV. ‘A criticism of Parts I, II, and III’, ibid., 1925, 62, 504–15. Pt. V. ‘The control of geological history by radioactivity’, ibid., 1925, 62, 534–44.

³⁷ Ibid. (Pt. IV), p. 504.

³⁸ Ibid., p. 507.

³⁹ Ibid., p. 515.

⁴⁰ Ibid., p. 515.

⁴¹ Ibid. (Pt. V), p. 534.

⁴² Ibid., p. 534.

⁴³ Ibid., p. 544.

⁴⁴ Holmes, A., ‘Radioactivity and earth movements’, Transactions of the Geological Society of Glasgow, 1931 (for 1928–1929), 27, 567–606.Google Scholar

⁴⁵ Holmes, A., ‘Some problems of physical geology and the earth's thermal history’, Geological magazine, 1927, 64, 263–78.CrossRefGoogle Scholar

⁴⁶ Ibid., p. 263.

⁴⁷ Ibid., p. 263.

⁴⁸ Ibid., p. 276.

⁴⁹ Ibid., p. 276.

⁵⁰ Holmes, A., ‘Radioactivity and continental drift’, Geological magazine, 1928, 65, 236–38.Google Scholar

⁵¹ Ibid.

⁵² Holmes, A.. ‘Continental drift’, Nature, 1928, 122, 431–3.CrossRefGoogle Scholar

⁵³ Holmes, , op. cit. (19).Google Scholar

⁵⁴ Holmes, , op. cit. (45).Google Scholar

⁵⁵ Holmes, , op. cit. (50), p. 237.Google Scholar

⁵⁶ Ibid., p. 237.

⁵⁷ Ibid., p. 237.

⁵⁸ Holmes, , op. cit. (52), p. 432.Google Scholar

⁵⁹ Holmes, , op. cit. (44), p. 574.Google Scholar

⁶⁰ In modern parlance ‘substratum’ is ‘mantle’.

⁶¹ Ibid., p. 569.

⁶² Ibid., p. 574.

⁶³ Ibid., p. 579. Figures reproduced by kind permission of the Geological Society of Glasgow.

⁶⁴ Ibid., p. 580.

⁶⁵ Ibid., p. 577.

⁶⁶ Ibid., p. 577.

⁶⁷ Ibid., p. 577.

⁶⁸ Holmes, A., Principles of physical geology, New York, 1945, p. 508.Google Scholar

⁶⁹ Holmes, , op. cit. (19), p. 347.Google Scholar

⁷⁰ Holmes, , op. cit. (44), p. 585.Google Scholar

⁷¹ Ibid., pp. 580–1.

⁷² Ibid., pp. 580–1.

⁷³ Ibid., p. 600.

⁷⁴ Ibid., p. 600.

⁷⁵ Cf. Marvin, , op. cit. (5), p. 105Google Scholar and Hallam, , op. cit (5), p. 36.Google Scholar

⁷⁶ Jeffreys, H. in ‘Problems of the earth's crust: a discussion in Section E (Geography) of the British Association on 28 September 1931 in the Hall of the Society’, Geographical journal, 1931, 78, 433–55 (453).Google Scholar

⁷⁷ Cf. Jeffreys' comments about Holmes in Jeffreys, ibid.

⁷⁸ Ibid., p. 453.

⁷⁹ Cf. Holmes, , op. cit. (19), p. 346Google Scholar and Holmes, , op. cit. (68), pp. 505–6.Google Scholar

⁸⁰ Holmes, , op. cit. (68), pp. 505–6.Google Scholar

⁸¹ Hallam cites as a possible reason for the neglect of Holmes' hypothesis the fact that his major paper (1931) appeared in such an obscure journal. However, I am sceptical about this because, as we have seen, Holmes stated his hypothesis in more popular journals, and included it in his widely circulated Principles of physical geology—the first edition of which was reprinted 18 times.

⁸² It is certainly true that there were geologists who did not belong to the contractionist programme, namely those who followed permanentism. The first real champion of permanentism was James Dana, who proposed it in 1846 in an article entitled ‘On volcanoes of the moon’. The work appeared in The American journal of science and arts. Bailey Willis resurrected Dana's permanentism in 1907 and 1910. Most permanentists, like Willis and Dana, lived in America.

⁸³ Jeffreys, , op. cit. (76), p. 452.Google Scholar

⁸⁴ Ibid., pp. 452–3.

⁸⁵ Holmes, A. in ‘A continuation of problems of the earth's crust: a discussion in Section E (Geography) of the British Association on 28 September 1931 in the Hall of the Society’, Geographical journal, 1931, 78, 536–44 (542).Google Scholar

⁸⁶ Cf. Marvin, , op. cit. (5)Google Scholar and Hallam, , op. cit. (5)Google Scholar. In addition, the changes in geology brought about by the development of techniques which could test hypotheses similar to Holmes' (e.g. Hess' hypothesis of seafloor spreading), through the advancement of oceanography, is dramatically illustrated by Menard. Menard traces the spectacular rise in the number of citations given to Hess' ‘History of ocean basins’ (the first published explication by Hess of his seafloor spreading hypothesis) after its corroboration by the confirmation of e.g., the Vine-Matthews hypothesis. Menard, H., Science: growth and change, Cambridge, Mass., 1971, pp. 119–25.CrossRefGoogle Scholar

⁸⁷ Cited in Marvin, , op. cit. (5), p. 103.Google Scholar