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FOREWORD

by FREDERICK HENRY STEWART

T H I s V O L U M E is dedicated to Professor ARTHUR HOLMES, a man to whom Earth scientists, whether geochronologically inclined or not, look as one of the great geologists of the century. Those of us fortunate enough to know Holmes personally find him a quiet man of extraordinary charm, willing to take enormous trouble to help lesser mortals with their problems. All of us know him as a man of brilliant ideas. He has exercised a profound influence on almost all branches of geology, not only through his own remarkable researches but also by his beautifully written textbooks (on which many of us were weaned) and his stimulation of the research qualities of his students--first in , where he built up a new department from scratch, and later in Edinburgh University, which was honoured with his occupation of the Chair of Geology for thirteen years and with his presence as Emeritus Professor for six years after he retired in I956. Holmes has made a great number of contributions to our knowledge of the geology of many parts of the world, from his home district in the north of England to Africa, India, and elsewhere, but the descriptive aspect of his work has been, far more than with most men, merely a prelude to his remarkable studies of the wider genetic problems of our science. He has gone deep into the major questions of the origin of igneous rocks, partly in association with his accomplished and eminent wife, Dr . He was never a man to shun controversy or to be trammelled by tradition, and his work on the origin of the alkaline rocks of Africa and elsewhere, on the thorny problems of and their associates, on the origin and development of magmas, and on the role of metasomafism in rock genesis has broadened the vision of igneous and metamorphic petrologists all over the world. His contributions on the geophysical aspects of geology are classic: the nature of orogenic and epeirogenic activity, movements in the Earth's mantle, con- tinental drift, radioactivity in geology--one could go on for a long time listing the aspects of geology to which he has made major contributions. In fact there is hardly a main branch of the subject, other than palaeontology, with which his name is not associated. And undoubtedly one of his greatest gifts to science has been his work on geological time. Holmes was born at Hebburn, near , in I89O, six years before the discovery of radioactivity by Becquerel, at a time when the ages of rocks and of the Earth were being hotly debated by geologists and physicists with no apparent prospect of agreement. By I897 Kelvin, from heat-flow considerations, had reduced the time since the Earth's consolidation to between 20 and 4 ° million years. Many geologists requiied much more time for the formation of immensely thick sedimentary successions by processes similar to those of the present day, and Joly and Geikie arrived at figures of the order of I oo million years or more, while Quart. 37. geol. Soc. Lond. vol. I2o s, I964, pp. 3-I I, frontispiece. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

F. H. Stewart Goodchild estimated 704 million years from the base of the Cambrian. It was some time before it became apparent from Strutt's work that the Earth's supply of heat from radioactivity made nonsense of the estimates of the physicists, and before it was realized by Rutherford, in 19o3, that radioactivity might provide a means for determining the age of minerals in terms of millions of years. During his schooldays Holmes's inquiring mind had questioned the magic date for the Creation, 4OO4B.C., in Archbishop Ussher's chronology for the book of Genesis, and in the sixth form his interest in geology was awakened by an enlightened schoolmaster who encouraged him to read Kelvin and Suess. As an undergraduate of Imperial College he began more formal studies in 19o7, the year in which Boltwood calculated approximate ages of a number of -bearing minerals from lead ratios. After work in the laboratory of Strutt, whose studies of helium in minerals gave results consistent with those of Boltwood, Holmes published his first paper in 1911 in the Proceedings of the Royal Society: 'The association of lcad with uranium in rock-minerals, and its application to the measurement of geological time'. In this work he gave estimates of ages of minerals which did not at all please some of the older geologists of the time, but which, considering the state of knowledge of radio- active phenomena at that time, were remarkably close to those now accepted. Since that first paper, Holmes has published more than fifty contributions on the subject of radiometric age, ranging from works on the end-product of thorium, the distribution of radium, and the radioactivity of potassium, to Pre-Cambrian and post-Cambrian time-scales and the age of the Earth. In 1947 he gave us a Phanero- zoic time-scale which was the Bible of geologists for a long time. The post-war explosion of work on age, with the appearance of new methods, led to his revision of this time-scale in 1959, and he wrote at that time (Holmes 1959, p. 184) : 'The revised time-scale.., will also require revision in its turn, since each year the dated control points become more numerous, more precisely fixed, and less unevenly distributed through the geological column'. That is the object of this volume, and we hope that it and future revisions may not bc too unworthy for dedication to a man who was aptly described by one of the speakers at the symposium as the 'genius in the business'.

[Professor] F. H. Stewart, PH.D.F.R.S.F.R..~.E.F.G.S. Grant Instituteof Geology, West Mains Road, Edinburgh 9

ARTHUR HOLMES, D.SC. A.R.C.S.M.R.I.A. LL.D.F.R.S.E.F.R.S.F.G.S. Born 14 January I89O , at Hebburn-on-Tyne; Imperial College, , 19o7-I o; expedition to , I9I I ; Demonstrator in Geology, Imperial College, 1912-2o; Chief Geologist, Yomah Oil Co., Burma, 192o-3; Reader and Professor of Geology, Durham Colleges, University of Durham, 1924-43; Regius Professor of Geology, , I943-56, Professor Emeritus since I956; Exchange Professor, University of Basle, 1930; Lowell Lecturer, Harvard Univer- sity, 1932; Foreign Honorary Member American Academy of Arts and Sciences, 1934; Correspondent Geological Society of America, 1936; Honorary Member Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

Foreword: Arthur Holmes Royal Geological Society of Cornwall, x937; Corresponding Member Geological Society of Belgium, i946 , Honorary Member, 1956; Honorary Member Belgian Society of Geology, Palaeontology, and Hydrology, 1947; Foreign Member Royal Swedish Academy of Sciences, 1947; Foreign Member Royal Netherlands Academy of Sciences, 1947; Foreign Member Geological Society of Stockholm, 1952; Foreign Member Academy of Sciences, Institute of France, 1955; Murehison Medal, Geological Society of London, x94o, Wollaston Medal, I956; Penrose Medal, Geological Society of America, 1956; Fourmarier Medal, Royal Academy of Belgium, 1957; Fellow of Imperial College, I959; Hon. LL.D., Edinburgh, x960; Vetlesen Prize, 1964. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

Works by Arthur Holmes

[Within any one year, items have been arranged in the following sequence: books; original papers; book reviews, etc. Works of joint authorship are placed at the end of the items for each year.]

HOLmeS, A. 191 i. The association of lead with uranium in rock-minerals, and its application to the measurement of geological time. Proc. roy. Soc. (A), 85, 248--56. I91 I. The duration of geological time. Nature, Lond. 87, 9-1o. & WRAY, D. A. 1912. Outlines of the geology of Mozambique. Geol. Mag. (5) 9, 412-7 •

-- & ~ 1913. Mozambique: a geographical study. Geogr. 07. 42, 143-52. 1913. The age of the Earth. London & New York (Harper). xii+ I96 pp. 1913. Radium and the evolution of the Earth's crust. Nature, Lond. 9 x, 398.

-- 1914. Lead and the final product of thorium. Nature, Lond. 93, lO9. 1914 . The terrestrial distribution of radium. Sci. Progr. 9, 12-46. 1914. The lateritic deposits of Mozambique. Geol. Mag. (6) z, 529-37. & LAWSON, R. W. 1914. Lead and the end product of thorium. (Part I). Phil. Mag. (6) 28, 823-4 ° . i915. Radio-activity and the measurement of geological time. Proc. Geol. Ass., Lond. 26, 289- 309. 1915. Radio-activity and the Earth's thermal history. Part I. The concentration of the radio- active elements in the Earth's crust. Geol. Mag. (6) 2, 6o-7 I. 1915. Radio-activity and the Earth's thermal history. Part II. Radio-activity and the Earth as a cooling body. Geol. Mag. (6) 2, IO2-I2. -- 19I 5. A contribution to the petrology of north-western Angola. Geol. Mag. (6) 2, 228-32; 267-72; 322--8; 366-7o. & LAWSON, R. W. 1915. Lead and the end product of thorium. (Part II). Phil. Mag. (6) ~'9, 673-88. 1916. Radio-activity and geology. [Book review] Geol. Mag. (6) 3, 176-8.

-- 19 I6. Contribution to the discussion on radio-active evidence of the age of the Earth. Rep. Brit. Ass. 1915, 432-4. --- 1916. Radio-activity and the Earth's thermal history. Part III. Radio-activlty and isostasy. Geol. Mag. (6) 3, 265-74. I916. Notes on the structure of the Tanganyika-Nile rift valley. Geogr. 07. 48, 149-59. --- 1916. On a series of volcanic rocks from the neighbourhood of the LucuUa River, Angola. Miner. Mag. zS, 58-75 . -- 1916. Coral reefs and the ice age. [Book review] Geogr. 07. 48, 4I 1-I5. 1917. The Tertiary volcanic rocks of the district of Mozambique. Quart. 07. geol. Soc. Lond. 72 [for I916], 222-78. ~- I9I 7. A mineralogical classification of igneous rocks. Geol. Mag. (6) 4, 115-3o. -- 1917. Picrite from the Ampwihi River, Mozambique. Geol. Mag. (6) 4, 15o-7 •

-- 1917" Albite--granophyre and quartz-porphyry from Brandy Gill, Carrock Fell. Geol. Mag. (6) 4, 4o3-7. 1917 . [Comment on 'The stability of lead from thorium,' by F. Soddy.] Nature, Lond. 99, 245. 1918. The basaltic rocks of the Arctic region. Miner. Mag. I8, I8O-223. -- 1919- Pre-Cambrian and associated rocks of the district of Mozambique. Quart. 07. geol. Soc. Lond. 74, 31-97 • 19I 9. The geology of concrete aggregates. Concr. constr. Engng, 14, 333-6. ~. 19I 9. Non-German sources of potash. Geol. Mag. (6) 6, 251-4, 34o-5 o. 1919. A modern theory of the earth. [Book review] Observatory, No. 537, 127-31. z92o. The nomenclature of petrology. London (Murby). 284 pp. I92o. The measurement of geological time. Discovery, x, lO8-14. -- 1921. Petrographic methods and calculations. London (Murby). xix+ 515 PP. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

F. H. Stewart

HOLMES, A. I921. Geological and physical characters of concrete aggregates with special refer- ence to British resources as illustrated by the aggregates used in a series of fire tests conducted by the British Fire Prevention Committee (i917-i919). Red Bks Fire Prey. Comm. (Brig. Ass.) 256, I7I pp. [D.S.I.R. publication]. -- • SMITH, STANLEY. I92I. The Wackerfield dyke, County Durham. Geol. Mag. 58, 440-54. 1923. Petrographic methods and calculations. Part I: Specific gravity, separation and deter- mination of minerals, detrital sediments (pp. 1-23o); Part II: The study of thin sections (pp. 231-383) ; Part III: Chemical methods and calculations (pp. 384-515). -- t923. The age of the Earth. [Book review] Nature, Lond. Ix2, 3o2-3 . I924. The evolution and disintegration of matter. [Book review] Min. Mag., Lond. 3 x, 356-8. ~- I925. The origin of the continents. Nature, Lond. zx5, 873-4. ---- 1925. Radioactivity and the Earth's thermal history. Part IV: A criticism of Parts I, II and III. Geol. Mag. 62, 5o4-15. --- 1925. Radioactivity and the Earth's thermal history. Part V: The control ofgeological history by radioactivity. Geol. Mag. 62, 529-44. I925. Radioactivity and Earth history. [Book review] Geogr. 07. 65, 528-32. I925. The Earth, its origin, history, and physical construction [sic]. [Book review] Min. Mag., Lond. 32, 93-7.

-- I925. Radioactivity and geology. [Book review] Nature, Lond. Ix6, 89I- 3.

-- x926. Contributions to the theory of magmafic cycles. Geol. Mag. 63, 3o6-29. I926. Estimates of geological time, with special reference to thorium minerals and uranium haloes. Phil. Mag. (7) x, io55-74. 1926. Vulcanism and metallogeny. Geol. Mag. 63, 335. I926. Rock-lead, ore-lead, and the age of the Earth..Nature, Lond. zzT, 482. I926. The geological age of the earth. Nature, Lond. zzT, 592-4.

-- I926. The structure of the continents. Nature, Lond. xxS, 586. --- I926. Tectonic features of New Guinea. Nature, Lond. xzS, 848- 9. -- I926. Tectonic geology and geophysics. [Book review] Geogr. 37. 68, 26I-4. & LnwsoN, R. W. I926. Potassium and the heat of the Earth. Nature, Lond. xtT, 62o-I. & ~ I926. The radioactivity of potassium and its geological significance. Phil. Mag. (7) 2, I218-33. ----- & ~ I926. Calculation of the ages of radioactive minerals. Nature, Lond. zxS, 478. ---- I927. The age of the Earth: an introduction to geological ideas. London (Benn). 8o pp. ---- 1927. The effect of radon on the solubility of lead uranate. Phil. Mag. (7) 4, I242. I927. Oceanic deeps and the thickness of the continents. Nature, Lond. x2o, 8o4-5. I927. Some problems of physical geology and the Earth's thermal history. Geol. Mag. 64, 263-78. I927. The unstable Earth. [Book review] Geogr. 07. 69, I5I-5. I927--8. The problem of geological time. Scientia, Bologna, 42, ~'63-72, 329-36; 43, 7-I6. [French translation in Supplement 42, 123-32, I52--8; Supplement 43, 7-x 5].

--& LAwson, R. W. 1927. Factors involved in the calculation of the ages of radioactive minerals. Amer. 37. Sci. (5) 13, 327-44- 1928. The foundations of Durham Castle and the geology of the Wear gorge. Durham Univer- sity 37ournal, z928 , 1-8. 1928. Radioactivity and . [Report of Glasgow Geological Society meeting on x2 January i928 ] Geol. Mag. 55, 236-8. ----- I928. Continental drift. [Book review] Nature, Lond. x'~t2, 43I-3 . & HARWOOD, H. F. I928. The age and composition of the Whin sill and the related dikes of the north of England. Miner. Mag. 2z, 493-542. I928-29. Radioactivity and earth movements. Trans. geol. Soe. Glasg. z8 (3), 559-6o6.

-- I929. Ore-lead and rock-lead and the origin of certain ore deposits. Nature, Lond. x~, 477-8. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

Works by Arthur Holmes

I-Io~ Mm, A. x929. A review of the continental drift hypothesis. Min. Mag., Lond. 4o, 2o5-9, 286--8, 34o-7 • --z929. An introduction to geology. In Broadcasts to schools .from Newcastle Station 22 April-2 x 07une, z929; notes on local courses for schools. London (British Broadcasting Corpora- tion), pp. x7-3 z [Notes on a series of nine lessons broadcast from 26 April to 2I June i929]. i929. Origin and physical constitution oft he Earth. [Book review] Geogr. 07. 7x, 584-8. x929. The evolution of the igneous rocks. [Book review] Min. Mag., Lond. 4 x, 285-7. DUB~Y, V. S. & HoT ~ms, A. I929. Estimates ofthe ages of the Whin sill and the Cleveland dyke by the helium method. Nature, Lond. x23, 794-5. YIoT ~ms, A. & H~wooo, H. F. z929. The tholeiite dikes of the north of England. Miner. Mag. 22, z-5~,. - i93o. Petrographic methods and calculations. (2nd edn) London (Murby). xix+515 pp. --- x93o. The nomenclature of petrology. (2nd edn) London (Murby). 284 pp. I93o. Radioactivity and geology. [Abstract] Trans. Edinb. geol. Soc. x2, 28z-3. --" x93o. The period of 'actino-uranium' and its bearing on the ages of radioactive minerals. Nature, Lond. x26, 348-9. x93o. Radioaktivit~it und Geologic. Verh. naturf. Ges. Basel, 4x, I36-85 • --- I93o. Geologic mad Radioaktivit~it. [Book review] Geol. Mag. 67, 37-9. & LAWSON, R. W. z93o. [Comment on 'The product of the radioactive disintegration of potassium' by Frost, A. V. & Frost, O.] Nature, Lond. xos, 48. I93i. Radioaktivit~it und die thermische Geschichte der Erde. Naturwissenschaften, x9, 73-9. --- x93 I. The problem of the association of acid and basic rocks in central complexes. Geol. Mag. 68, 24x-55 . x93i. Coneretionary and oolitic structures of the Permian rocks. Proe. Geol. Ass., Lond. 42, 255-9. -- x93x. The theory of geological thermal cycles. Nature, Lond. x27, 5tS--z9. z93 I. Radioactivity and earth movements. Nature, L0nd. x28, 496. x93i. Lead content of rocks. Nature, Lond. x28, xo38-4o. 193 I. Problems of the Earth's crust. Geogr. 07. 78, 445-5 I, 54z-2. -- x93x. Radioactivity and geological time. Bull. nat. Res. Court., Wash. 80, x24-459. & ~WOOD, H. F. I932. Petrology of the volcanic fields east and south-east of Ruwenzori, Uganda. Quart. 07. geol. Soc. Lond. 88, 37o-439- -- x93 I. Tectonic geology of the Mediterranean. [Book review] Geogr. 07. 78, z6 x-3. Hxca~rNo, G. & HOLMm, A. t 93 I. The breeeiation of the Permian rocks [of Durham]. Proe. Geol. Ass., Lond. 42, 252-5. HoT.m~s, A. & Mocgxa~R, G. S. x93I. Late and Tertiary intrusions [of Northum- berland and Durham]. Proe. Geol. Ass., Lond. ate, 26x-7I. x932. The origin of igneous rocks. Geol. Mag. 69, 543-58. x932. [Contribution to] Discussion on the origin of igneous rocks. Rep. Brit. Ass. x932, 33 t-2. ---- I932. Glaciation and continental drift. Geogr. 07. 80, I77. I933. The Toro-Ankole volcanic fields. Rep. geol. Surv. Uganda, xg~, 48-5 o. z933. The genesis of leucite and melilite rocks. Geol. Mag. 70, z4o--2. -- z933. The thermal history of the Earth. 07. Wash. Acad. Sci. 23, z69-95. z933. The genesis of the diamond. [Book review] Min. Mag., Lond. 48, 154-6. z934. The Gordonia uraninite and the upper pre-Cambrian rocks of southern Africa. Amer. 07. Sci. (5) 27, 343-53. x935. The measurement of geological time. Nature, Lond. x35, 68o'-3. z936. Geological time and former glaciations in relation to evolution of solar system. [Ab- stract] Pan-Amer. Geol. 66 (3), 23o-I. I936. The idea of contrasted differentiation. Geol. Mag. 73, 228--38. x936. A record of new analyses of Tertiary igneous rocks (Antrim and Staffa). Proc. R. Irish Acad. (B), 43 (8), 89-94. -- x936. Transfusion of quartz xenoliths in alkali basic and ultrabasie lavas, south-west Uganda. Miner. Mag. 24, 4o8-2 z. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

F. H. Stewart HOLMES, A. 1936. Geological time and former glaciations in relation to the evolution of the Solar System, [Abstract of contribution to discussion on the origin of the Solar System] Rep. Brit. Ass. x936 , 32o-I. ~. & PAN~a~, F. A. I936. Helium-ratios ofrocks and minerals from the diamond pipes of South Africa. Proc. roy. Soc. (A), x54, 385-413- I937. The age of the Earth. (new edn, revised and rewritten) London (Nelson). 263 pp. x937. The origin of primary lead ores. Econ. Geol. 32, 763-82. x937. A contribution to the petrology of kimberlite and its inclusions. Trans. geol. Soc. S. Afr. 39, 379-428. I937. The idea of contrasted differentiation. Geol. Mag. 74, t89-9x. x937. Foreword to Silicate analysis by GROVES, A. W. pp. ix-xvi. London (Murby). x937. The petrology of katungite. Geol. Mag. 74, 2°o-I9. & HARWOOD, H. F. I937. The volc~_ic area of Bufumbira. Part II : The petrology of the volcanic field of Bufumbira, south-west Uganda, and of other parts of the Birunga field. Mere. geol. Surv. Uganda, 3 (2). 3oo pp. I938. The origin of primary lead ores: Paper II. Econ. Geol. 33, 829-67 • x939. The geologist's clock. In The wild life around us and the story of the rocks, lEd. Cox, I.] London (Allen & Unwin), pp. 182-9o. [Reprint of a broadcast talk.] I94O. A idade da terra. Introduc.~o as peorias geol6licas... Lisboa (Praduc~o de Alexandre Martins Correia). Io4 pp. 194o. Basaltic lavas of South Kivu, Belgian Congo. Geol. Mag. 77, 89-IOI. URRY, W. D. & HOLMES, A. I941. Age determination of Carboniferous basic rocks of Shropshire and Colonsay. Geol. Mag. 78, 45-61 [Part I by Urry; Part II (geological relations and petrology) by Holmes.] HOLMES, A. 1942. A suite of volcanic rocks from south-west Uganda containing kalsilite (a poly- morph of KA1SiO4). Miner. Mag. 26, 197-217. I942. A heteromorph of venanzite. Geol. Mag. 79, 225-32. I944. Principles of physical geology. London (Nelson). xii+532 pp. x944. The age of the Earth. [Inaugural lecture, x943.] University of Edinburgh oTournal, autumn 1944, 12-2o. - I945. Leucitized xenoliths from the potash-rich lavas of Bunyaruguru, south-west Uganda. Amer. o7. Sci. 243-A, 3t3-32. x945. Natural history of granite. Nature, Lond. I55 , 412-5 . I945. The Giant's Causeway. Nature, Lond. I56 , 425--6. I945. Histoire natureUe du granite. Bull. Soc. belge G~ol. Pal. Hydr. 54, 26o-7 I. [Translation of the 1945 Nature paper.] I945. Natural history of granite. Quarry Mgrs'J. 29 (4), I68-75. COMB~, A. D. & Ho~ ~ms, A. 1945. The kalsilite-bearing lavas of Kabirenge and Lyakauli, south- west Uganda. Trans. roy. Soc. Edinb. (B), 6x, 359--79 [Part I by Combe; Part II (petrology) by Holmes]. I-IoT M~s, A. 1946. Art estimate of the age of the Earth. Nature, Lond. x57, 68o- 4. I947. The age of the earth. Endeavour, 6, 99-IO8. [See I95o for fuller version of same paper] I947. A revised estimate of the age of the earth. Nature, Lond. I59 , I27-8. I947. The age of the Earth. World Digest, Dec. I947, PP. 45-7. [Condensed version of the I947 Endeavour paper.] I947. An estimate &the age of the Earth. Geol. Mag. 84, I23-6. 1947. The construction of a geological time-scale. Trans. geol. Soc. Glasg. 2x, I 17-52. - & REYNOLDS, DORIS L. 1947" A front of metasomatic metamorphism in the Dalradian of Co. Donegal. Bull. Comm. ggol. Finl. 24 (I4O), 25-65. 1948. A idade da terre. Minerac. e MetaU. 13, 24 I-8. [Translation of the 1947 Endeavour paper. ] I948. The oldest known minerals and rocks. Trans. Edinb. geol. Soc. x4, I76-94. I948. [Report to National Research Council, Division of Geology and Geography.] Rep. Comm. Meas. geol. Time, I946--7, Exhibit B, pp. 39--46. Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

Works by Arthur Holmes

Ho~.~s, A. & S~s, A. A. 1948. Monazite from Bodmin Moor, Cornwall: a study in geo- chronology. Proc. roy. Soc. Edinb. (a), 63, 115-29 [Part I (monazite as a geological timekeeper) by Holmes; Part II by Smiles]. 1949. The term ' magma-type '. Geol. Mag. 86, 71-2. I949. The age of uraninite and monazite from the post-Delhi of Rajputana. Geol. Mag. 86, 288-3o2. i949. Lead isotopes and the age of the Earth. Nature, Lond. 163, 453-6. --- 1949. [Obituary notice of] Mr. A. D. Coombe. Nature, Lond. 164, 95. I949. [Report to National Research Council, Division of Geology and Geography.] Rep. Comm. Meas. geol. Time, 19474 , Exhibit A, pp. 16-20. • I95O. The age of the Earth: Rep. Smithson. Instn. 1948, 227-39. [Fuller version of the 1947 Endeavour paper]. I95O. Age of uranlnite from a near Singar, Gaya district, India (with an isotopic analysis by W. T. Leland and A. O. Nier). Amer. Miner. 35, 19-28. 195o. The age of uraninlte from Gordonia, South Africa. Amer. 07. Sci. 248, 81-94. - 195o. Petrogenesis ofkatungite and its associates. Amer. Miner. 35, 772-92. - I950. Pre-Carnbrian formations of India. Geol. Mag. 87, 227-8. --- 195o. [Obituary notice of] William Whitehead Watts. Tearb. roy. Soc. Edinb. 1948 and i949, PP. 49-5o. -- I95i. Evidence of lava formation in situ, south-west Uganda. Geol. Mag. 88, 73-87. 1951. The sequence of Pre-Cambrian orogenic belts in South and central Africa. Int. geol. Congr. 18 (I4), 254-69. x952. The potash ankaratrite-melaleucitite liras of Nabugando and Mbuga craters, south- west Uganda. Trans. Edinb. geoL Soc. z5, 187-313. 1952. Geologia fisica. Barcelona (Ediciones Omega). 519 pp. [Spanish translation of 8th reprint of Principles of physical geology.] i953. Gravity measurements over the northern Pennines. Geol. Mag. 90, 221-2. -- 1953. The South Atlantic: land bridges or continental drift ? [Book review] Nature, Lond. zTx , 669-7 I. 1954. The oldest dated minerals of the Rhodesian shield. Nature, Lond. 173, 612-4. -- 1954. [Obituary notice of] Dr. Harold Rutledge. Nature, Lond. x73, 85I. -- 1954. [Obituary notice of] Dr. Harold Rutledge. Proc. geol. Soc. Lond. I5Z5, cxlii-cxliii. & B~sAmI~, H. 1954. Premiers mesures de g6ochronologie ~t Madagascar. Mgm. Inst. sci. Madagascar (D). 6, 19 I-9. -- & I954. Sur quelques mesures de g6ochronologie ~ Madagascar. C.R. Acad. ScL, Paris

238, 758-60. REYNOI~DS, D. L. & FIOLm~S, A. 1954. The superposition of Caledonoid folds on an older fold- system in the Dalradlans of Malin Head, Co. Donegal. Geol. Mag. 9 x, 417-44 . HOLMES, A. 1955. Dating the of Peninsular India and Ceylon. Proc. geol. Ass. Can. 7 (2), 8i-io6. - 1955. Report on British vulcanological research during the period September 1939-March 1954. Part I--Great Britain and . Bull. volcan. (II), 16, 115-24. Part II-- British Colonial Territories. Ibid. pp. I25-35. Part IV--Other contributions by British authors. Ibid. pp. 142-5- ---- 1955. Interpretation of nature. In The Crust of the Earth. New York (Signet Key Book). PP. 26-43. The age of the Earth. Ibid. pp. 159-67. -- 1955. Isotopes in the service of geology. [Book review] Nature, Lond. I76, lO38-9 . ----- & CArtoN, L. 1955. African --results available to I September I954. Colon. Geol. min. Resour. 5, 3-39. ---- & ~ 1955. G6ochronologie africaine: rfsultats acquis au I er septembre 1954- Compte rendu et communications de l'Association des Services g~ologiques africains. Rdunion de Nairobi (1954). Bureau d'Etudes g~ologiques et mini6res coloniales, Paris, pp. 59-98. , SHILLIBEER, H. A. & WILSON, J. T. 1955. Potassium-argon agee of some Lewisian and Fenno- scandian pegmatites. Nature, Lond. 176 , 39o-2. IO Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021

F. H. Stewart

HOLMES, A. I956. How old is the Earth? Trans. Edinb. geol. Soc. x6, 313-33. I956. The ejectamenta of Katwe crater, south-west Uganda. Verh. ned. geol.-mijnb. Genoot (Geol. Ser.) x6 (Brouwer Jubilee Volume), i39-66. & CAHEN, L. I957. G~ochronologie africaine i956. R~sultats acquis au ierjuillet I956. Mgm. Acad. R. Belg. Cl. Sci. 5 ( I ). x957. Response by Arthur Holmes [to presentation of the Penrose Medal of the Geological Society of America]. Proc. geol. Soc. Amer. for x956 , 74--6. I958. Spitskop carbonatite, eastern Transvaal. Bull. geol. Soc. Amer. 69, x525--6. --- 1959. A revised geological time-scale. Trans. Edinb. geol. Soc. x7, x83-216. ~- & CAH~N, L. x959. G~ochronologie africaine (R~sultats aequis au xer juillet x956 ). Int, geol. Congr. 2o, Asociacion de Servicios Geologicos Africanos, 2 I- 5. I96o. [Reply to G. W. Wetherill.] Nature, Lond. x$7, 35-6. I96o. [Obituary notice of] Alexander Murray Cockburn. Yearb. roy. Soc. Edinb. x959/xg~, 83-6. x96I. A farrago of Earth history. [Book review] Nature, Lond. x89, 34I-2. x962. 'Absolute age' a meaningless term..Nature, Lond. x96, 1238. x963. Introduction to The Precambrian. (ed RAN~CAMA, K.) vol. I, pp. xi-xxiv. New York & London (Interscience Publishers). - x964. Principles of physical geology. [New edn, completely rewritten.] London (Nelson). xvi -~ I26o pp.

Contribution from Professor L. R. WAGER: investigations, particularly on the age of the Oslo igneous province by the U-Pb method men- I should like to add to the remarks made by tioned by Professor Stewart. When I used to call Professor Stewart. on Holmes in Durham in the 193os, and when In this symposium on the time- I succeeded him in x943, there were great jars scale we are dealing with only one facet of of yellow liquid in his room which were being Professor Arthur Holmes's work. He has been used for the determination of uranium in rocks equally, or possibly more, concerned with the by the helium method of age-determination. Pre-Cambrian time-scale and equally or more Actually, however, Holmes took little part in with the question of the age of the Earth by the experimental side of age-determination means of lead isotopes. work, and on more than one occasion he has But, as Professor Stewart has said, he is also expressed to me his regret at this. He would, a very great petrologist and geophysicist. To no doubt, have liked to have been involved in take only one example, his bold thinking forty the experimental aspect of the work; but years ago on convection currents in the mantle might he not then have become too deeply may well prove to have been the prelude to involved, and perhaps, therefore, not have one of the greatest steps forward of this century made his great contributions to the broader and in the geosciences. more philosophical problems concerned with Holmes himselfcarried out early experimental the Earth ?