eS ern = Bore oe Se THE GEOLOGICAL MAGAZINE. DECADE V. VOL. III. JANUARY—DECEMBER, 1906. “GHOLOGICAL MAGAZINE Monthly Houynal of Geology : Hk Gan Ow © G 1s 1.” : NOS. CCCCXCIX TO DX. EDITED BY HENRY WOODWARD, LL.D., F.R.S., V.P.Z.S., WP ACiatsey Wolecla ila). LATE OF THE BRITISH MUSEUM OF NATURAL HISTORY 3 PRESIDENT OF THE PALHONTOGRAPHICAL SOCIETY, PAST PRESIDENT OF THE MALACOLOGICAL SOCIETY ; MEMBER OF THE LYCEUM OF NATURAL HISTORY, NEW YORK; AND OF THE AMERICAN PHILOSOPHICAL SOCLETY, PHILADILPHIA; HONORARY MEMBER OF THE YORKSHIRE PHILOSOPHICAL SOCIETY; OF THE GEOLOGISTS’ ASSOCIATION, LONDON: OF THE INSTITUTION OF MINING AND METALLURGY, LONDON; OF. THE GEOLOGICAL SOCIETIES OF EDINBURGH, GLASGOW. HALIFAX, LIVERPOOL, AND SOUTH AFRICA; CORRESPONDING MEMBER OF THE GEOLOGICAL SOCIETY OF BELGIUM; OF THE IMPERIAL SOCIETY OF NATURAL HISTORY OF MOSCOW; OF THE NATURAL HISTORY SOCIETY OF MONTREAL; AND OF THE MALACOLOGICAL SOCIETY OF BELGIUM. ASSISTED BY WILFRID H. HUDLESTON, M.A., F.RB.S., F.G.S., F.L.S., F.C.S. | GEORGE J. HINDE, Px.D., F.RS., F.G.S., &. AND HORACE BOLINGBROKE WOODWARD, F.R.S., V.P.G.S., &c. NEW SERIES. DECADE V. VOL. IIt. JANUARY—DECEMBER, 1906. TIORNEDIOENs: MESSRS. DULAU & CO., 37, SOHO SQUARE, W. 1906. [7/06 HERTFORD: PRINTED BY STEPHEN AUSTIN ANI) SONS, LTD. LIST OF PLATES. FACING PAGE Portrait of T. McKenny Hughes, M.A., F.R.S., F.G.S., F.S.A. Chalk Bluffs at Trimmingham, Norfolk Chalk Biuffs at Trimmingham, Norfolk Chalk Bluffs at Trimmingham, Norfolk Chalk Bluffs at Trimmingham, Norfolk Corals from Eastern Egypt Corals from Eastern Egypt Chalk Bluffs at Trimmingham, Nortolk Chalk Bluffs at Trimmingham, Norfolk Fossil Kchinoidea from Sinai and Egypt Fossil Echinoidea from Sinai and Egypt Skulls of two species of a Horned Tortoise Corries in the Comeragh Mountains : ; Geological Sketch-map of the district bordering the Helford Basin Pigmy Hippopotamus from Cyprus . Bokkeveld Fossils, South Africa Bokkeveld Fossils, South Africa Mollusca, Bryozoa, and Foraminifera from Crete Foraminifera from Crete : Ordovician Gasteropoda from Haverfordwest . Permian Breccias and Conglomerate Trelogan Quarry, Halkyn Mountain Waenbrodlas Quarry, Halkyn Mountain Portrait of Joseph Frederick Whiteaves, LL.D., F.R.S., F.G.S. Ichthyosaurus showing contained Embryos Mesozoic Fossils from Singapore Rhizophyllum robustum, Shearsby, etc. Chalk Arch, Trimmingham, Norfolk 1 17 22 we Se ir epee a be mish Wiah? MER ine ri i rs oe ae | eee hy |) Se Mm AE ulna nae nee. 78 im dT Panh 24 Yale eirtat) sivties le Meeetant; a SP ait, Cedi - illus hee | one eed til wt ogl dian G (tp T ee th tay Nuits ienlah be maa aig, mi ‘Traht a jp alt eat way ny ora dae oe ah ie ; tq y i weataral, eeay koi ewe eae vat ihe Mig tl ro rest 9 * bia el Oe th ite mee att ay ca va Wiel lApide: Ftp ayy aa inner eee " ip : iat a Sah A H thats ‘slants bievwall A fata A Mt) Dex oy vonmeMy>S hs} Vili List of Illustrations in the Text. Semieschara Woodsi, sp. nov., Chalk, Trimmingham S. Pergensi, sp. nov. »”? 99 Cribrilina Gregoryi, sp. nov. i) “ Brachylepas (Mitella) lithotryoides ,, - Scalpellum fossula. (Nomenclature of the valves.) Pollicipes mitella. . 3 ; Brachylepas ( Pollicipes) fallax, Chalk, Trimmingham Poliicipes Angelini, Chalk, Norwich and Trimmingham 340 341, 342, 343, 344 346 P. Hausmanni, P. coneinna, and P. striatus, Chalk, Norwich and Trimmingham 347 Scalpellum maximum, Chalk, Norwich . 350 S. fossula and S. attenuatum, Chalk, Norwich, and Brachylepus sp.,'‘Trimmingham 352 Diagram-section Eastern flank of Halkyn Mountain . ** Westerly Chalk Bluff,” Trimingham, Norfolk Remnant of Bluff near Trimingham, Norfolk Contour Map of Haystacks Mountain Roche moutonnée, Blackbeck Tarn Outlet of Blackbeck Tarn Tarn formed by wind-erosion of peat, Haystacks Mountain Zones of the Lower Chalk . Stratigraphical Distribution of Fossils Plan of part of the hill behind Keisley Section across west end of Dutton Inlier Carboniferous Succession in the Bristol District and in N. Wales Section at Grange Quarry, Holloway Section of Lower Williams Creek, Cariboo, B.C. Natural Arch on the Sea-shore, 'Trimmingham, Norfolk Section of Cliff, Trimmingham, Norfolk ERRATA. p. 144, 1. 21 from foot: after from insert Holiths. 394 401 403 407 407 408, 409 411 414, 415 458 483 484 p- 159, 1. 2 from foot: for ‘‘ two lower” read ‘‘ lower two.”’ p- 400, note 2, 1. 5: for ‘*‘ Weymouth’’ read ‘*‘ Weybourne,”’ p- 518, 1. 22: for ‘‘are’’ read ‘* is.” Price 1s. 6d. net. GEOLOGICAL MAGAZINE A cumnat of Geology. CH dilonthty WITH WHICH IS INCORPORATED “THE GERHOLOGIST.” EDITED BY mean RY WOODWARD, LL.D., F:R.S., é ASSISTED BY WILFRID H. HUDLESTON, F.R.S., &c., Dz. GEORGE J. HINDE, F.R.S., &c., AND HORACE B. WOODWARD, F.R.S., &c. No. 499. Decade V.—Vol. III.—No. I. F.G.S., &c. J ANUARY, 1906. CONTENTS. IT. Orteinan Arricuus. Page , Notices or Memorrs—(continued) Page _ Eminent Living Geologists : Tuomas The Karroo Beds of South Africa. McKenny Hueues, M.A.,F.R.S., By Prof. R. Broom, M.D., B.Sc. 36 F.G.8., F.S.A., Woodwardian The Stormberg Formation of Cape Professor of Geology. (With a Colony. By Alex. L. du Toit, B.A. 36 Portrait, Plate I.) scoousesuacoddoscoads 1 Index Generum et Speciern- Ani- Further Notes on the ‘Trimmingham mmalitin sc UR ee 38 Bide MOTO: by TMi: BRY= 02 p20 ee ES , ponn, F.G.S. (Plates II and III II. Reyreys- ACN VOC CUI) fo cee2 Ac oe.s scavenge anes 13 On the Raised Beaches of the Geo- M. Yokeyama, Mesozoic Plants from logical Survey of Scotland. By JAAD Sek. - eek, eer elope 38 ie. Jawreson, BG.S. ...2.06.0... 92 | Dr. G.F. Matthew, Batrachian Foot- Fossil Insect trom the Coal-measures prints stats, eliha (sfalavevayht sie slelahejctalerelelcfelela) ae Teeseieiecie 39 of North Staffordshire. By Hunry Prof. Sollas, Roe ks of New Zealand... 39 Woopwarp, LL.D., F.RB.S., Geology of the Malay States ......... 40 F.G.S. (With 5 Text-Figs.)...... 25 The Permian and Triassic Faunas of IV. Reports anp Proceepines. South Africa. By Professor R. : : ie Heproom. MMs; DSc oe oases 29 Se eet pocety of Loudee 4] On the Tiveaular Behinoids of the cmeseie eee White Chalk of England. By C. Mineralogical Society of London— Davies SHERBORN, Gwe 31 Wwovemberl4the 1905 44 Wenlock, Ludlow, and Taunusian St oe) cap SaaS - Fossils from Looe, Cornwall. B ee Urrietp Green, F.G.S., and C. We Cuts nome Gr. Davies SHERBORN, F.G.S. ...... 33 ve ae Sea M.A. i We v1 46 HI, Nomices oy Muacoms, EU Ghia eee British Association for the Advance- ment of Science: Meeting in South V1. Oprrvary. Africa, 1905. Papers read before Section C :— Professor G. Dewalque (Belgium), Ore Veins and Pegmatites. By Prof. For. Memb. Geol. Soc. Lond. . 48 SME CKGE cio sic vsiacesciiee sucecsistears sine 35 | Professor E. Oustalet (Paris) .....,... 48 LONDON: DULAU & O0., 37, SOHO SQUARE. — 4 — ¢¢ The Volume for 1905 of the GEOLOGICAL MAGAZINE is ready, Cloth Cases for Binding may be had, price 1s. 6d. net. price 20s. net. ROBERT F. DAMON, WEYMOUTH, ENGLAND, Is now supplying carefully prepared Coloured Casts of the AUSTRALIAN MUD FISH, FROM THE RIVERS OF QUEENSLAND, CERATODUS FORSTERI, KREFFT, Measuring 3ft. x 10in. = 9lem. x 25cm. 3 Price - £3. le Also Czsts of the upper and lower halves of the Head, showing Teeth, Nares, etc., lying side by side on a slab, Measuring 10in. x 6in. = 25cm. x 15cm. Price = £1 10s. ADDRESS: ROBERT F. DAMON, WEYMOUTH, ENGLAND. GHOLOGICAL MAGAZINE, NEW SERIES. DECADE V. VOL. Ill. No. I.—JANUARY, 1906. Ore Gs NeAS tes) PACs ans Cree Se — J.—Eminent Livinc Gerotoaists: THOMAS McKENNY HUGHES, M.A., F.R.S., F.G.S., F.S.A., Woodwardian Professor of Geology in the University of Cambridge ; of Trinity College, Cambridge ; Professorial Fellow of Clare College, Cambridge ; Chevalier of the Order SS. Maurice et Lazarus, Italia; Corr. Memb. Geol. Soc. Belgium, France, Germany, Italy, etc. (WITH A PORTRAIT, PLATE I.) AV the great body of geologists, who are justly entitled by their work in this field of science to rank as ‘ knights- commanders of the hammer,” there is no one more distinguished, as well for his active services as for the geniality of his disposition and — his bonhomie, than the amiable and accomplished occupant of the Woodwardian Chair of Geology in the University of Cambridge, Professor T. McKenny Hughes. He was born at Aberystwyth, in Wales, and is the son of that most famous and popular Bishop of St. Asaph (1807-1889) well known as a prelate who preached and talked to his people fluently in Welsh, and was beloved by all in his diocese accordingly. Mr. T. McKenny Hughes is also brother of the present Bishop of Llandaff, and a grandson of Sir Thomas McKenny, Bart., who took a very prominent part in promoting Catholic emancipation and similar movements in Ireland. Spending much of his early days in the Principality, Mr. Hughes naturally acquired a thorough knowledge of Welsh, and has never ceased to cherish a love for the Cambrian mountains and valleys of his native land, where he also imbibed from association much of the happy disposition and quickness of mode characteristic of the Welsh people, together with their love of music and anecdote. His early education was acquired at Leamington and Llandovery Colleges, whence he afterwards entered at Trinity College, Cambridge, in 1858. While an undergraduate he was an associate of the Ray DECADE V.—VOL. III.—NO. I. 1 2 Eminent Living Geologists— Club, and a constant attendant at Professor Sedgwick’s lectures in the Woodwardian Museum. After taking his Bachelor’s degree in 1857, he was engaged in tuition for two years, during which his geological tendencies were for the time in abeyance. Mr. Hughes did not proceed to take his M.A. degree until ten years later, in 1867. At the commencement of the year 1860 a new career seemed to be opening to Mr. Hughes, when he received the appointment of Secretary to Mr. (afterwards Sir) C. T. Newton, K.C.B., H.B.M. Consul in Rome, where later in that year, and in 1861, Mr. Hughes was left in charge as Acting-Consul. During his residence in Rome he took the opportunity to study the sub-Apennine formations on the hills around the Eternal City, and made collections of fossils from them, and also from the more recent deposits of the Valley of the Tiber. One of the most interesting episodes in his life was when he was left Acting-Consul in Rome in 1860 and 1861, when Garibaldi was marching on the city and all sorts of mercenaries were collected to meet him. Among them was a brigade of Irishmen, who gave more trouble to the Papal officers themselves than to the enemy. He was often called in to help to arrange matters officieusement between the officers and their men, who could not understand one another’s language. This kind of training abroad gave him au experience in dealing with men which he has found useful ever since. Yn 1861 he had the option of accompanying Lord Odo Russell to Berlin, and at the same time he received an invitation from Sir Roderick Murchison to join the staff of the Geological Survey of Great Britain. In this “meeting of the waters” his love for geology prevailed, he bade adieu to Rome, and to what seemed to promise in the future a brilliant diplomatic career, and he returned to England as a “ Royal hammerer.” Accordingly we find Mr. Hughes later on in 1861 duly installed as an Assistant Geologist on the Geological Survey of Great Britain, Sir Roderick I. Murchison being then Director-General, and Professor A. C. Ramsay, Director. He commenced work, and was occupied during several field seasons in mapping the Chalk and Lower Eocene strata along the Medway Valley, and near Faversham and Sittingbourne ; and his observations on this region were published in Mr. Whitaker’s Memoir on the Geology of the London Basin (Mem. Geol. Surv., vol. iv, 1872). The Chalk was then divided into broad lithological divisions, which were carefully described with regard to their local features, economic products, and leading fossils; and Mr. Hughes remarked that ‘“‘ from the varying character of the beds and the irregular occurrence of the layers of flints, it is very probable that the same horizon may not have been everywhere taken as the base of the Upper Chalk.” Attention was called to the accumulations of chalk and flint rubble that have attracted much notice during recent years ; and also to the layer of unworn green- coated flints that usually occurs at the top of the Chalk, where it is covered by the Thanet Sand. Mr. Hughes (in a paper read before Professor T. McKenny Hughes, F.R.S., F.G.S. 3 the Geological Society in 1866) gave reasons for believing that the layer was due to the dissolution of the top beds of the Chalk after the deposition of the Thanet Sand. He also dealt with Sheppey, the rapid waste of its coast, and the curious mounds in the adjacent marshes, that had been a puzzle to antiquaries, but might well be attributed to tidal action and the modifying effects of subaérial denudation. He pointed out that the Medway, below Cuxton, flows along the line of a gentle anticlinal axis in the Chalk, and he discussed the effects of denudation on the permanent water-level in the Chalk. Working later (1865-6) in the country near Hertford and St. Albans, Mr. Hughes described the drift gravels under two heads; that of the Lower Plain, which for the most part is the ordinary mixed glacial gravel associated with the Chalky Boulder-clay, and that of the Higher Plain, consisting chiefly of pebbles of flint, quartz, etc., which he regarded as a marine deposit, and he hinted at its possible Pliocene age. In 1866 Mr. Hughes was transferred to the Lake District where the Geological Survey had commenced operations under the super- intendence of W. T’. Aveline. In that region he had the satisfaction of meeting his old master, Sedgwick, on his own ground, working in the neighbourhood of Kirkby Lonsdale, Dent, and Sedbergh. There, too, he was ever a welcome guest in the country houses, and after a hard day’s tramp across mountain and moor, he frequently rode many miles on horseback from his quarters to dinner or dance. His personality has always readily turned strangers into friends amongst rich and poor. Once, after a long day’s work in the Crossfell country, he went into a lonely cottage and asked the good woman to give him something to eat. She did so, and when he had finished he said, ‘‘ What is there to pay?” ‘Nowt at a’, nowt at a’,” she replied, “‘ yer cumpany’s good!” He now zealously paid attention to the fossils of the Silurian and other rocks on the borders of Westmorland and Yorkshire, and his observations communicated to the GeonogicaL Magazine for 1867 led him to confirm the breach between the Upper and Lower Silurian, and to support the view of Sedgwick that the Coniston Flags formed the base of the upper division. The publication of these views was, we believe, received with some disapprobation on the part of the Director-General of the Geological Survey. The main results of his field-work were printed subsequently in Memoirs on the geology of the neighbourhood of Kirkby Lonsdale and Kendal (written in conjunction with Mr. W. T. Aveline and Mr. R. H. Tiddeman), and on the geology of the country around Kendal, Sedbergh, Bowness, and Tebay (with W. T. Aveline). In describing the ‘‘ Upper Old Red Conglomerate ” he remarked on the unfortunate introduction into the district of the term “ Old Red,” as the conglomerate was truly the Basement Bed of the Carboniferous Series. With reference to the Yoredale Rocks, he observed that “They thus form a kind of passage from the Mountain Limestone to the Millstone Grit, and should, perhaps, be considered 4 Eminent Living Geologists— as the upper part of the Mountain Limestone split up by shales and sandstones.” In all his notes published by the Geological Survey we find careful attention paid to the work of previous observers, and many acute observations on the facts and phenomena that came before him. It was while serving as an Assistant Geologist on the Geological Survey that the Chair of Geology in Cambr idge became vacant by the death, in his 88th year, of the illustrious Professor Adam Sedgwick, on the 27th January, 1873, after occupying that position for 55 years. By Statute of the University, the appointment must take place within one month from the vacancy being declared, so that on the 20th February, 1873, the Heads of Houses, Professors, University Examiners, and resident members of the Senate proceeded to elect a successor, no fewer than nine candidates having offered themselves for the post. Most of these, however, withdrew without going to the poll, while other candidates early retired from the contest, which finally resulted in the election of Mr. Hughes by a small majority over Professor Bonney. Both before and after his election to the chair, Professor Hughes was intimately associated with the late Sir Charles Lyell, with whom he made several foreign and British tours. Lyell frequently mentions his friend—‘‘ Mr. T. M’K. Hughes, now Woodwardian Professor at Cambridge ”—in the fourth edition of his ‘ Antiquity of Man,” when, in the Spring of 1872, they visited together the cave of Aurignac and the caverns of Dordogne. Asa lecturer Professor Hughes is extremely fluent and clear in his delivery, and he makes excellent use of the chalk and blackboard to aid his demonstrations. He is also a most popular man with his students and at the meetings of his fellow-workers at the Geological Society of London. The remarkable feature of Professor Hughes’ work in Cambridge has been the large number of men of mark who have studied under him, and also the very strong list of graduates who have joined the teaching staff in what is now justly recognised as “the Cambridge School of Geology.” We recall with pleasure some of these who have taken distinguished places in the world, and a few who have already ended their work well :— 1874.! Walter Keeping, M.A., Professor of Natural Science, Aberystwyth University. 1875. Robert D. Roberts, D.Se. .. M.A., F.G.S., University of London, ete. 1875. Aubrey Strahan, M.A., F.R.S , Geological Survey of England and Wales. 1878. Edward B. Tawney, M. AG Bs G. S. ., Assistant to the W oodwardian Professor. 1879. J. E. Marr, M.A., Se.D., F.R.S., President Geol. Soe. London (Reader in Geology in the Univ ersity of Cambridge). 1879. T. H. D. La Touche, M.A., Superintendent Geol. Survey of India. 1880. C.S. Middlemiss, M.A., F. G.S , Superintendent Geol. Survey of India. 1880. Arthur S. Reid, M. As RE. G.S 8. , Trinity College, Glenalmond. 1881. W.H. Herries, B.A.; F.G.S., ” New Zealand. 1 The date affixed is that of the first degree taken at Cambridge. Where the date could not be ascertained, a dash is put instead of the year. —Eprr. Gron. Mac. 1882. 1882. 1883. 1885. 1883. 1884. 1884. 1886. 1886. 1886. 1887. 1888. 1888. 1888. Professor 1. McKenny Hughes, F.B.S., F.GS. 5 Professor W. W. Watts, M.A., M.Sc., F.R.S., Sec. Geol. Soc. London ; University of Birmingham. Alfred Harker, M.A., F.R.S. [Geol. Survey of Scotland (retired)], Fellow of St. John’s College, Cambridge; University Lecturer in Petrology. Rev. W. M. Lower Carter, M.A., F.G.S., Sec. Yorks. Geol. Polyt. Soc. T. Roberts, M.A., F.G.S., Assistant to the Woodwardian Professor. Eyan W. Small, M.A., B.Sc. J. R. Ainsworth Davis, Professor University College, Aberystwyth. Robert 8. Herries, M.A., V.P. Geol. Soc. J.W. Carr, M.A., F.L.S., F.G.S., Professor University College, Nottingham. A. C. Seward, M.A., F.R.S., F.L.S., Fellow of Emmanuel College, Cambridge; University Lecturer in Botany, Cambridge. Professor E. J. Garwood, M.A., Sec. Geol. Soc. London; Professor of Geology, University College, London. Philip Lake, M.A., F.G.S., Lecturer at Colchester College. Professor T. H. Easterfield, M.A., Wellington, New Zealand. Arthur Hutchinson, M.A., Ph.D., F.C.S., F.G.S., Demonstrator in Mineralogy in the University of Cambridge. Robert Ludwig Mond, M.A., F.R.S. E., F.G.S. 1888 (took Tripos). Marie Wilman, South African Museum, Cape Town. 1889. 1889. 1889. 1889. 1889. S. F. Dufton, M.A., H.M. Inspector of Schools. Professor T. T. Groom, M.A., D.Sc. Lond., F.G.S., University College, Reading. C. H. Hawes, M.A., traveller and author. Professor S. H. Reynolds, M.A., F.G.8., Professor of Geology, University College, Bristol. Herbert Warington Smyth, M.A., LL.M., F.G.S., Secretary to the Mines Department, Transvaal. 1890 (Classical Tripos, 1st Class). C. B. Wedd, B.A., F.G.S., Geol. Survey of 1890. 1891. 1891. 1891. 1891. 1892. 1893. 1894. 1894-5. England and Wales. H. Woods, M.A., F.G.S., University Lecturer in Paleozoology, Cambridge. Harry Brownsword, M.A., The Leys School, Cambridge. H. Kynaston, B.A., F.G.8., Director of the Geol. Survey of the Transvaal Colony, Pretoria. EH. A. Peters, B.A., M.D. F. R. Cowper Reed, M.A., F.G.8., Assistant to the Woodwardian Professor. L. J. Spencer, M.A., F.G.S., Department of Mineralogy, British Museum (Nat. Hist.). F. L. Kitchin, M.A., Ph.D., F.G.S., Paleontologist to Geol. Survey of Great Britain. A. W. Rogers, M.A., F.G.S., Director of the Geol. Survey of Cape Colony. Miss Gertrude L. Elles, D.Sc., Assistant to the Woodwardian Professor ; Newnham College. R. Hawthorn Kitson, B.A., F.G.S., Leeds. Miss Ethel M. R. Wood, M.Sc., Birmingham University ; Newnham Coll. E. H. Cunningham - Craig, B.A., F.G.8., Geol. Survey of Scotland (temporarily of Trinidad). H. H. Thomas, M.A., F.G.S., Geol. Survey of England. H. Stanley Jevons, B.A., F.G.S8., University College, Cardiff. KH. A. Newell Arber, M.A., Demonstrator in Paleobotany, Geol. Mus., Cambridge. W. G. Fearnsides, M.A., F.G.S., Fellow of Sidney Sussex College, Assistant Demonstrator, Geol. Mus., Cambridge. foe Ferrar, M.A., F.G.8., Antarctic explorer on ‘‘ Discovery’’; Survey of Egypt. K. Loe Hallowes, B.A., Assoc.R.S.M., F.G.S., Geol. Survey of India. H. B. Muff, B.A., F.G.S., Geol. Survey of Scotland. i. B. Bailey, B.A., F.G.S., Geol. Survey of Scotland. R. H. Rastall, B.A., F.G.S., Assistant Demonstrator, Geol. Mus., Cambridge. F. B. Smith, B.A., Agricultural College, Africa. L. W. Hinxman, B.A., Geological Survey of Scotland. G. W. Grabham, B.A., F.G.S., Geol. Survey of England. Owen Thomas Jones, B.A., Geol. Survey of England. 6 Eminent Living Geologists — The first man who joined Professor Hughes’ teaching staff, by special invitation, was the well-known geologist Mr. Edward B. Tawney. He was not a graduate of the University in the ordinary sense of the term, having taken his honours and his training at the Royal School of Mines and elsewhere. He became Professor Hughes’ earliest assistant in 1878. In the Academic year following the University conferred on him the honorary degree of M.A. (propter merita), but he did not long survive to carry on the splendid work of teaching. He died in 1882 at the comparatively early age of 42; but he accomplished much good work in his lifetime, as may be seen by reference to his published papers.! Another excellent teacher, T. Roberts, M.A., followed in 1883, and continued until his death in 1892, having taken up more especially the Jurassic rocks as his line of research. Dr. J. E. Marr, M.A., F.R.S., Pres. Geol. Soc., commenced teaching in 1879, dealing specially with the older rocks, and is “Reader in Geology” in the University of Cambridge. Mr. Alfred Harker, M.A., F.R.S., has also done much valuable work in advancing the study of petrology, and in teaching the nature of rock-structures, more especially of the igneous rocks. Mr. Henry Woods, M.A., F.G.S., Lecturer on Paleozoology, deals with a branch of study pursued also by Mr. F. R. Cowper Reed, M.A., F.G.S.; the latter also takes an earnest and active part in the Museum arrangements. Miss G. L. Elles, D.Sc., has likewise assisted the Professor of Geology as a demonstrator to his classes. With such advantages afforded them, what wonder then, if the geologists who leave the Cambridge University are so well equipped that they now mostly occupy leading positions in Museums, upon Geological Surveys, and in the teaching of the science, not only at home but in India and in our Colonies. Nor must it be forgotten (if we except the Ashmolean Museum, opened in 1683) that Cambridge had its splendid Woodwardian Museum from an earlier date even than the sister University of Oxford, although, till late, far too “cabin’d, cribb’d, and confin’d” for want of adequate exhibition space. In 1838 it was decided by the University to build a museum for geology; and the popularity of Professor Sedgwick was so great that a sum of £23,400 was readily collected by public subscription, to which was added £4,000 from the Woodwardian Trust Funds. Cockerell’s Building was erected with the help of these funds, and to the geological collection the two lower floors were assigned. But this accommodation, owing to the large accessions made to the geological collections, had been obviously inadequate for many years past. On the death of Professor Sedgwick in 1878, it was decided that the memorial to him should take the form of a new and larger Museum ; and in that year a public subscription was opened for this purpose, and a sum raised which ultimately amounted to over £28,000. The public recognition of the value of geology as a subject for University teaching in Cambridge has thus been demonstrated, 1 Grou. Mac., 1883, pp. 140-144. Professor T. McKenny Hughes, F.RS., £.G.S. a upon two occasions, in a very substantial manner. A writer at the time! says :—“ After a long series of disappointments and difficulties the indefatigable energy and perseverance of Professor Sedgwick’s successor, Professor T. McKenny Hughes, have triumphed over the countless obstacles which hindered the realisation of the scheme. . . . The Architect of the building is Mr. T. G. Jackson, R.A., and he has had the difficult task of designing a museum which should satisfy the needs of the Geological Department and the requirements of the various University syndicates. . . . Whatever may be the opinion of these bodies, the staff and students have good reason to be well pleased with the ample accommodation provided for them, and the collections are now adequately exhibited in the new galleries. Research and other laboratories are provided, and the principal lecture-room is capable of accommodating a class of 120 students. Midway between the galleries for Paleozoic and Neozoic fossils stands the bronze statue of Professor Sedgwick, with his geological hammer in one hand and a slab bearing the Cambrian Trilobite Angelina Sedgwickii in the other.” One who graduated more than fifty years ago, and knew the old Museum in Sedgwick’s lifetime, strolled into the new building in Downing Street, Cambridge, the other day, and, seeing the glories of the Museum for the first time, was heard to exclaim : “‘How different all this is from what it was in my time! How I envy the students and the teachers who are privileged to study and work at geology under such favourable conditions as they now enjoy! I should like to have my time over again in 1906.” Remembering the removal of the geological collections of the British Museum from Bloomsbury to South Kensington in 1880, the writer can well understand the enormous difficulties which Professor Hughes must have encountered, with only a very small staff at his command, in carrying out the task of removing the Woodwardian collections from the old building into their new home, and their subsequent rearrangement. : But we must not dwell too long upon the ‘“‘Sedgwick Memorial Museum,” save to refer to it as one of the great and important objects carried out by Professor Hughes in connection with the teaching of geology in the University during his term of office. After the death of the Rev. Canon Charles Kingsley, the founder and President of the Chester Society of Natural Science, in 1875, Professor T. McKenny Hughes was elected his successor, and delivered several addresses to its members during his term of office. He received the ‘‘ Kingsley Memorial Medal,” established in memory of Charles Kingsley by the Chester Naturalists. Professor Hughes was likewise President of the Kendal Literary and Scientific Society. While devoting his energies so largely to the work of the University, Professor Hughes continued to carry on field-work in various parts of the country, notably in Wales, both among the more ancient rocks and among the caves and Drift deposits. The list of 1 Grou. Mac., 1903, pp. 532-534, 8 Eminent Living Geologists— papers appended to this memoir will sufficiently indicate these labours, but we may recall attention to one subject that has since attracted a good deal of notice. In his paper “On the Brecciated Bed in the Dimetian at St. Davids” (Gron. Maa., 1883, p. 306), he discussed the origin of certain breccias and brecciated conglomerates in homogeneous rocks, and the breaking up and recementing of rock-masses in place. He gave a diagram of a brecciated granitoid rock near Bryngarn. composed of large and small subangular fragments, and this bed (which would now be spoken of as a “crush conglomerate”) was described as ‘“‘not of transport origin, but represents brecciation in place and subsequent weathering along the joint planes.” In February, 1891, Sir Archibald Geikie, F.R.S., the President of the Geological Society, announced that the Lyell Medal had been awarded by the Council to Professor T. McKenny Hughes, in appreciation of the value of his investigations in various departments of geology, especially among the older rocks. He referred particularly to Professor Hughes’ researches in Caernarvonshire and Anglesey, which formed the starting-point to those later inquiries which had done so much to clear up the earlier chapters in the geological history of Wales. <‘‘ You have,” said the President, ‘‘ not confined yourself, however, to the rocks of any one system or period, but have ranged freely from Archean gneiss to raised beach . . . . with that happy faculty of enthusiasm which, reacting on younger minds, ‘allures to older worlds and leads the way.’ This medal will not only serve to mark the Society’s appreciation of your work, but will also connect you by another link with the memory of our friend and master, Lyell.” Professor Hughes was elected a Fellow of the Geological Society in 1862 and a Fellow of the Royal Society in 1889. At the meeting of the International Geological Congress held in Paris in 1878, Professor Hughes was appointed a member of the Commission for the unification of geological signs and geological nomenclature and classification. He was chosen President of the British Committee of Organisation to deal with the subjects of classification and nomenclature. Five sub-committees were formed and their reports were issued in 1885, and revised and amplified in a second edition in 1888. To the latter Professor Hughes contributed an interesting and philosophic preface on the rules which should guide us in our classification of strata, and in our descriptions of rocks, fossils, and geological sections. Professor Hughes continued to attend the meetings of the Congress up to that at Zurich in 1894. On the completion of the 25th year of his Professorship, he was entertained by his friends at a public dinner in London, February 26th, 1898, when he was presented with an illuminated address by his students and fellow-workers congratulating him upon the success of the Cambridge School of Geology under his charge. Professor Hughes married, November 28th, 1882, Mary Caroline, daughter of the Rev. George F. Weston, Honorary Canon of Carlisle Professor T. McKenny Hughes, F.R.S., F-G.S. 9 Cathedral. Mrs. Hughes inherits the artistic skill of her father and mother; she isa good linguist and has extensive scientific knowledge, but she devotes herself now entirely to her husband’s pursuits. She is a keen geologist, and, in the field on geological excursions, her presence is greatly appreciated. The writer recalls a delightful excursion some years ago to the Wrekin, led by Professor Lapworth, in which Professor and Mrs. McKenny Hughes took part, and he remembers seeing the three happily engaged hammering at a block of Hollybush sandstone, from which Mrs. Hughes, with her own hammer, extracted some good remains of Olenellus, to the joy of the party. In the far western wilds of America, when their commissariat broke down, Mrs. Hughes cooked for a party of 17, and was described by one of the speakers at the closing meeting as “un vrai rayon de soleil dans nos miséres.” In Russia, after announcing Mrs. Hughes’ arrival, the Report (Comptes Rendus, p. cclxxxii) adds, “depuis le charme de notre société.” She was the only lady member of the Reichstag at Berlin when old Von Dechen began his Presidential address ‘‘ Madame et Messieurs.” Mrs. Hughes worked long and diligently at the Pleistocene deposits in .the neighbourhood of Cambridge, and published an excellent paper thereon in the GronocicaL Macazrne for May, 1888 (pp. 193-207, illustrated by five sections). She also gave a very exhaustive list of the molluscan and other fossil remains found in the gravels and brickearth. Professor and Mrs. Hughes have a family of three sons: the eldest is a B.A. of Cambridge, and is studying to become an architect; the second son goes up next October; the third is still a schoolboy, but will, if he does not change his mind, take up geology. Professor Hughes has always been a keen student of archeology (as may be seen from his list of published papers), and has served the office of President of the Cambridge Antiquarian Society. He takes an active part in agricultural organisations, and has for the past two years been President cf the Cambridge and Isle of Ely Chamber of Agriculture. A good hall on the ground floor of the new Museum is allotted to Economic Geology, and a collection illustrative of this branch is being formed after the plan of De la Beche’s Museum, now unhappily removed from Jermyn Street. In looking back for half a century of our geological life, and recalling the long line of familiar faces, especially of those who in the days of our novitiate occupied the front rank, one is conscious of the changes which the fleeting years have wrought. Sir Archibald Geikie, addressing his friend Professor Hughes at the Geological Society in 1891, recalled the days of their early friendship, now faded so far into the dim past of life, when, as colleagues on the Geological Survey, they attended together the meetings of the ‘Geological Society in Somerset House, taking seats on a back row, 10 Eminent Living Geologists— and gazing down upon the magnates of the science seated beneath. “ Little,” said he, ‘did either of us dream that the whirligig of time would eventually place us where we find ourselves to-day.” Sir Archibald Geikie, although retired and no longer the official head of the Survey, occupies the important post of one of the Secretaries to the Royal Society, and is still full of energy and work. Professor T. McKenny Hughes carries on the duties of the Chair of Geology, and maintains active interest in all scientific matters connected with the University, more especially whatever concerns his beloved “Sedgwick Memorial Museum,” which is naturally his joy and crown of rejoicing for life, and the outward and visible sign of the high place which geology, paleontology, and petrology hold in Cambridge. The following is a list of Professor T. McKenny Hughes’ published papers and memoirs :— 1866. ‘‘Note on the Silurian Rocks of Casterton Low Fell, Kirkby Lonsdale, Westmoreland”’: Grox. Maa., Vol. III, pp. 206-208 (with a section). 3% ‘* Note on the Junction of the Thanet Sand and the Chalk, and of the Sand- gate Beds and Kentish Rag’’: Quart. Journ. Geol. Soc., vol. xxii, p. 402-404. 1867. ‘‘On the Break between the Upper and Lower Silurian Rocks of the Lake District, as seen between Kirkby Lonsdale and Malham, near Settle” : Geox. Maa., Vol. IV, pp. 346-356 (4 sections). 7 ‘Notes on the Geology of Parts of Yorkshire and Westmoreland ’’: Geol. Polytechnic Soc. W. Riding Yorks (read July 17, 1867). 1868. ‘‘On Flint Implements”: Soc. Antiq. Lond., vol. iv (March 19), p. 95 ; Geological and Natural History Repertory, No. 34, p. 126. Ap ‘¢On the Two Plains of Hertfordshire and their Gravels’’?: Quart. Journ. Geol. Soc., vol. xxiv, pp. 283-287 (with 2 sections). 1872. ‘‘Man in the Crag’’?: Guron. Mac., Vol. IX, pp. 247-250 (with 3 wood- cuts in the text). bs Mem. Geol. Survey: Explanation of Quarter Sheet 98 8.E., illustrating ‘“The Geology of the Neighbourhood of Kirkby Lonsdale and Kendal.” 55 Mem. Geol. Survey: Explanation of Quarter Sheet 98 N.E., ‘‘ The Geology of the Country around Kendal, Sedbergh, Bowness, and Tebay.”’ 2 Mem. Geol. Survey: parts of ‘‘ The Geology of the London Basin.”’ 1873-4. (Hughes & Rev. D. R. Thomas.) ‘*On the Occurrence of Felstone Implements of the Le Moustier type in Pontnewydd Cave”: Journ. Anth. Inst., vol. iii (1874), pp. 387-392. 1874. ‘Exploration of Cave Ha, near Giggleswick, Settle, Yorkshire’’: Journ. Anth. Inst., vol. iii, pp. 3838-387. 1876. ‘‘ Notes on the Classification of the Sedimentary Rocks’’: Rep. Brit. Assoc. for 1875, Trans. Sects., pp. 70-73. as “¢ Geological Measures of Time”’: Roy. Inst. Gt. Brit., Lecture, March 24 (Proc., vol. vill, pp. 129-136). 33 “On a Series of Specimens illustrating the Formation, Weathering, and Fracture of Flint,’’ with note by Professor Stuart; Proc. Camb. Phil. Soc., vol. iii, pt. 1, p. 12. KA ‘On the Evidence for Preglacial Man”’: Proc. Camb. Phil. Soc., vol. iii, pt. 1, pp. 16, 17. 1877. ‘* Antiquity of Man: the Evidence afforded by the Gravels and Brickearth”’ : Journ. Anth. Inst. (November). 3 ‘*On the Silurian Grits of Corwen, North Wales’’: Quart. Journ. Geol. Soc., vol. xxxili, pp. 207-212 (with 2 sections). 1878. ‘*On the Pre-Cambrian Rocks of Bangor’’: Quart. Journ. Geol. Soc., vol, xxxiy, pp. 187-146 (with a section). 3 ‘‘On the Base of the Silurian System’’: Proc. Camb. Phil. Soc., vol. iii, p. 67. Professor T. McKenny Hughes, F.BRS., F.GS. 11 ‘¢ On the Base of the Cambrian Rocks in North Wales’’: Proc. Camb. Phil. Soc., vol. ii, p. 89. ‘On the Relation of the Appearance and Duration of the various Forms of Life upon the Earth to the Breaks in the Continuity of the Sedimentary Strata”: Proc. Camb. Phil. Soc., vol. iii, pt. 6, pp. 247-208. ‘‘ Further observations on the Pre-Cambrian Rocks of Caernarvon’”’: Quart. Journ. Geol. Soc., vol. xxxv, pp. 682-693 (10 sections in text and folding plate xxxvi). “¢On the Silurian Rocks of the Valley of the Clwyd’’: Quart. Journ. Geol. Soc., vol. xxxv, pp. 694-698 (2 page sections). “The Present State of the Evidence bearing upon the question of the Antiquity of Man”: Journ. Trans. Vict. Inst., vol. xiii, pp. 316-327. ‘‘On the Transport of fine Mud and Vegetable Matter by Conterva”’: Proc. Camb. Phil. Soc., vol. ii, pp. 339-341. *©QOn the Geology of Anglesey” (No. 1): Quart. Journ. Geol. Soc., vol. xxxvi, pp. 237-240. On the Altered Rocks of Anglesea’’?: Proc. Camb. Phil. Soc., vol. iii, pt. 8, pp. 341-348. “On the Cae Scynan Boulder”: Ninth Rep. Brit. Assoc. Committee on Erratic Blocks (1882); Proc. Camb. Phil. Soc., vol. ili (1880), p. 89. ‘On the evidence of the later movements of Elevation and Depression in the British Isles’’: Journ. Trans. Vict. Inst., vol. xiv, pp. 248-262. ‘‘Notes on Italy, and what she is doing for Science”: Chester Soc. Nat. Sci. ; Chester Guardian, Nov. 5. “On the Basement Beds of the Cambrian of Anglesey”: GurOL. Mace., Dec. II, Vol. VIII, pp. 333-334. Professor Hughes communicated (Nov. 16) to the Geological Society a state- ment of the results of the International Geological Congress at Bologna : Proc. Geol. Soc., pp. 2-4; Quart. Journ. Geol. Soc., vol. xxviii. “On the Geology of Anglesey” (No. 2): Quart. Journ. Geol. Soc., vol. xxxviii, pp. 16-28 (with 4 sections in text). ‘© On the Lower Cambrian of Anglesea”: Rep. Brit. Assoc. for 1881, pp. 648, 644. “On the Gnarled Series of Amlwch and Holyhead in Anglesea”: Rep. Brit. Assoc., p. 644. ‘¢ Excursion of the Geologists’ Association to Bangor, Snowdon, Holyhead, etc.” : Proc. Geol. Assoc., vol. viii, No. 4, pp. 195-207. Biographical Notice of Adam Sedgwick: Proc. Yorks. Geol. Polytechnic Soc. (November). <©On the Brecciated Bed in the Dimetian at St. Davids”: Gro. Mae., Dec. II, Vol. X, pp. 306-309 (with a woodcut). ‘* On some Fossils supposed to have been found in the Pleistocene Gravels of Barnwell, near Cambridge’’: Grou. Mac., Dec. IT, Vol. X, pp. 454-496: (and list of Mollusca). The International Geological Congress at Berlin (postponed): Grou. Mac., Dec. LI, Vol. I, p. 432. On the so-called Spongia paradoxica, S. Woodw. (1830), from the Red and White Chalk of Hunstanton’’: Quart. Journ. Geol. Soc., vol. xl, pp. 273-279. ‘¢Qn some Tracks of Terrestrial and Freshwater Animals’’: Quart. Journ. Geol. Soc., vol. xl, pp. 178-186 (plates vili—xi). ‘On the supposed Roman Camp at Whitley, near Alston, and on the Maiden Way as a Roman Road’”’: Proc. Camb. Antiq. Soc., vol. vi (Nov. 10), p. 41. ‘‘Notes on the Geology of the Vale of Clwyd”: Proc. Chester Soc. Nat. Sci., No. 3 (8 plates); Gzon. Mac., Dec. III, Vol. III (1886), p. 89. “On some Perched Blocks and Associated Phenomena”: Quart. Journ. Geol. Soc., vol. xlii, pp. 527-539 (with 5 illustrations in the text). ‘¢On the Ffynon Beuno Caves’: Gzou. Mac., Dec. III, Vol. III, pp. 489-492. ‘¢ Qn the Silurian Rocks of North Wales’’: Rep. Brit. Assoc. Birmingham, Sect. C (Geology) ; Grou. Mac., Dec. ITI, Vol. IIT, p. 509. “¢ Notes on some Sections in the Arenig Series of North Wales and the Lake District’: op. cit.; Guon. Mae., op. cit., p. 509. 12 Eminent Living Geologists—Prof. T, McKenny Hughes. “On the Pleistocene Deposits of the Vale of Clwyd”: op. cit.; Gron. MaG., op. cit., pp. 509-510. “Caves and Cave Deposits’’?: Proc. Chester Soc. Nat. Sci. and Lit., pt. iv (1893), p. 161. “*On Caves”: Journ. Trans. Vict. Inst. (Feb. 21). “‘On the Ancient Earthworks between the Mouth of the Tyne and the Solway ’’: Proc. Camb. Antiq. Soc., vol. vi, p. 355 ; vol. ix (1895), p.172. “On the Drifts of the Vale of Clwyd and their relation to the Caves and Cave-Deposits”?: Quart. Journ. Geol. Soe., vol. xliii, pp. 73-120 (double plate ix and 4 figures in text). ‘On the Ancient Beach and Boulders near Braunton and Croyde, in North Devon”: Quart. Journ. Geol. Soc., vol. xliii, pp. 657-670 (with 6 text-figures). ““On some Brecciated Rock in the Archean of Malvern’’?: Gzoxu. Mac., Dec. III, Vol. IV, pp. 500-503 (with a woodcut). ‘Bursting Rock-Surtaces”?: Grou. Mae., loc. eit., pp. 511-512 (with a figure in text). **On the Position of the Obermittweida Conglomerate ’’: Quart. Journ. Geol. Soc., vol. xliv, pp. 20-24 (with a section in text). “On the Cae Gwyn Cave’’: Quart. Journ. Geol. Soc., vol. xliv, pp. 112-137 (with 8 text-illustrations). ‘* Note on the Lower Cambrian of Bethesda, North Wales’”?: Grou. Maa., Dee. III, Vol. VI, pp. 8-15 (with 4 text-figures) ; also p. 96. “On some Antiquities found near Hanxton, Cambridgeshire’: Proc. Camb. Antiq. Soc., vol. vii (May 13), p. 24. “On Cuts on Bone as evidence of Man’s Existence in Remote Ages’’: Journ. Trans. Vict. Inst. (May 6). “*On the Manner of Occurrence of Beekite, and its bearing upon the Origin of Siliceous Beds of Palwozoie Age’’?: Min. Mag., vol. viii, No. 40, p. 265. ‘‘The Life and Letters of the Reverend Adam Sedgwick.’? 2 vols. By J. W. Clark & T. McK. Hughes. 8yvo. Cambridge. “On the Recent Discovery of two Ancient Ditches and Objects of Medieval Date between Hobson Street and Sidney Street, Cambridge’’: Proc. Camb. Antiq. Soc., vol. viii, p. 32. “¢On some Ancient Ditches and Medieval Remains found in the course of Recent Excayations near the Pitt Press’’?: Proc. Camb, Antiq. Soc., vol. viii (Oct. 23), p. 255. “* On Offa’s Dyke”’ : Archzeologia, vol. liii; Proc. Camb. Antiq. Soc., vol. vii, p. 200. ‘ “* On the Castle Hill, Cambridge’’: Proc. Camb. Antiq. Soc., vol. viii, p. 173. ‘¢Criticism of the Geological Evidence for the Recurrence of Ice Ages”: Pt. i, ‘Condition of the Surface of the Boulders and of the Solid Rock’ (p. 98); Pt.1i, ‘The Mode of Transport of the Boulders and other Drift’ (p. 219); Pt. iii, ‘ The Evidence as to the Extent of Earth Movements, and their Relation to Glacial Phenomena’ (p. 224) ; Pt. iv, ‘Summing-up.’ “On the Camp at Ardoch in Perthshire’’: Proce. Camb. Antiq. Soc., vol. viii ; Archeeologia, vol. liv, pp. 267-872. ‘*On the more important breeds of Cattle which have been recognized in the British Isles in successive periods, and their relation to other archeological and historical discoveries”: Archeologia, vol. lv, pp. 125-158. Opening Address to the Antiquarian Section of the Archwological Institute at Canterbury, with discussion of ‘ Eoliths,’ etc.: Arch. Journ., vol. lili (September), p. 249. ‘On some Chipped Flints from the Plateau-Gravel of Salisbury and else- where’’?: Proc. Camb. Phil. Soc., vol. ix, p. 120. ‘On the evidence bearing upon the early history of man which is derived from the form, conditions of surface, and mode of occurrence of dressed flints’’: Arch. Journ. (December), vol. liv. ‘‘The Landing-place of St. Augustine,” being Dissertation III in ‘‘ The Mission of St. Augustine to England, according to the original documents,” being a handbook for the thirteenth centenary. Edited by Arthur James Mason, D.D. R. M. Brydone—Further Notes on the Trimmingham Chalk. 13- 1897. ‘‘On some Waxed Tablets said to have been found at Cambridge’’: Archeeologia, vol. lv, pp. 257-288; Proc. Camb. Antiq. Soc., vol. viii, . 41. * ‘“‘Further Observations on the Ditches round Ancient Cambridge, with special reference to the adjoiing ground’’: Proc. Camb. Antiq. Soc., vol. ix (Feb. 1), p. 370. 1898. ‘‘The Race represented in the Archaic Statues of Athens’: Cambridge Review (April 28). 1899. ‘*On Nationality ’’: Journ. Trans. Vict. Inst. (May 1). 0 “‘On the Archeology and the Geography of the Fenland’’: Journ. Brit. Arch. Assoc. (December). 1901. ‘‘ Marathon’”’: The Classical Review, vol. xv, No. 130; translated into- Modern Greek in Panathenaia (Nov. 30), p. 114. a “¢ Amber”’: Arch. Journ., vol. lvui, No. 229, p. 35. * “Soils, and Matters relating thereto”: Jour. Camb. and Isle of Ely Chamber of Agriculture (Feb. 9). 3 *‘On the Natural Forms which have suggested some of the commonest Implements of Stone, Bone, and Wood.” 1901-2. ‘‘Ingleborough,”’ Pt. i: Proc. Yorks. Geol. Polyt. Soc., vol. xiv, p..125: Pt. ii, ib., p. 323. 1902. ‘*On Ancient Horse-shoes’’: Proc. Camb. Antiq. Soc., vol. x, p. 249. $3 “‘On the Remains of the Dog, Prehistoric, Roman, and Medieval, found near Cambridge ’’: Proc. Camb. Antiq. Soc., vol. x, p. 254. 3 ‘‘The Early Potters’? Art in Britain’: Arch. Journ., vol. lix, No. 235, pp. 219-237. “¢On some indications of a Roman Potter’s Field near Jesus College, Cam- bridge’’: Proc. Camb. Antiq. Soc., vol. x, p. 194. s *‘On the Potter’s Field at Horningsea, with a Comparative Notice of the Kilns and Furnaces found in the Neighbourhood’’: Proc. Camb. Antiq. Soe., vol. x, p. 174. 1903. ‘‘Onsome Buried Buildings, with special reference to Herculaneum’”’: Arch. Journ., vol. lx, p. 256. 1904. ‘‘The War Ditches near Cherryhinton, Cambridge.”’ 1905. ‘‘ Arboriculture on large and small Agricultural Holdings’’: Journ. Camb. and Isle of Ely Chamber of Agriculture (Jan. 14). Professor Hughes has been a frequent contributor to Nature and other scientific periodicals. I].—FurtHer Novres on THE STRATIGRAPHY AND FAUNA OF THE TRIMMINGHAM CHALK. By R. M. Bryponz, F.G.S. (PLATES II AND III.) ([\HIS paper is primarily a record of observations made at Trimmingham since those recorded in a pamphlet entitled “The Stratigraphy and Fauna of the Trimmingham Chalk.’ ! But as the Polyzoa of the Trimmingham Chalk comprise a re- markably large number of species which appear to be at present undescribed and are very characteristic of this horizon, I have taken this opportunity of describing some of the most prominent of these forms, partly in the hope of directing the attention of other collectors to their range and partly to facilitate the classification of the very large quantity of material I have accumulated. I have- also taken this opportunity of giving a list of species from the Chalk between Cromer and Weybourne. 1 London: printed separately, Dulau & Co., 1900. 14. R. M. Brydone—Further Notes on the Trimmingham Chalk. In the recently published memoir of the Geological Survey on the Upper Chalk of England Mr. Jukes-Browne has established a zone of Ostrea lunata for the Trimmingham Chalk. It is clearly desirable that a formal zone should be so created now that the fauna is known to be so distinctive, in spite of the present impossibility of identifying its upper or lower boundary, but the choice of O. lunata as a zone-fossil, though natural, is unfortunate. O. lunata has two characteristics of an ideal zone-fossil in that it is, as far as we know, almost confined to the Trimmingham Chalk, and that in that Chalk zone it always occurs abundantly, if at all. But it fails to fulfil the most important requirement for a good zone-fossil in that it is not distributed all through its so-called zone. There are at least ten, and probably more, distinct horizons occurring in four sequences at different points. The relations of the members of each sequence to one another are quite clear; the relations of the sequences to one another are at present doubtful (except that 3 is clearly identical with part of 4), but I believe that series 1 is the uppermost and series 4 the lowest, and I often fancy that series 2 is composed of the bottom bed of series 1 and the upper beds of series 3. The series (in descending order in each case) is as follows :— 1, Grey chalk with abundance of small Ostrea vesicularis. White chalk with 0. lunata. a without O. dunata. a with O. dunata. Be without O. dunata. Grey chalk with O. canaliculata, O. inequicostata, Terebratula obesa, and Stegaster. . Grey chalk with O. canaliculata, O. inequicostata, T. obesa, and a grit seam or bed at base. White chalk with O. Zunata. we without O. dunata. 3. White chalk with O. dumata. 35 without O. dunata. Hard chalk, weathering very lumpy. 4. White chalk with 0. lwnata. o without O. lunata. Hard chalk, weathering very lumpy. White chalk very much mottled by grey blue streaks. (It has only just been disclosed below the hard chalk, and I cannot yet say anything of its fauna except that it does not contain O. lumata.) bo Now a remarkable thing about O. lunata is that it occurs exclusively (with the exception of one specimen) at the horizons noted as characterised by it. It will be seen that there are, at most, five of these, and at least nine without O. lunata. It is true that the horizons with O. lunata are all of some thickness, and owing to the vast profusion of beautiful specimens of this very striking form which they contain, and to their supplying the greater part of the two bluffs—the only chalk always accessible—they figure very prominently in one’s impressions of the Trimmingham Chalk as a whole. But it is safe to say that in more than half of the total thickness of Chalk exposed O. lunata is not to be found, and RA. M. Brydone—Further Notes on the Trimmingham Chalk. 15 this without reckoning in the thickness of the anomalous northern part of the south bluff, which may fairly be quoted as not containing O. lunata, as only one specimen has been found in it, and that very dwarfed. But there are fossils which do occur throughout the Trimmingham Chalk, yet, as far as I know, are confined to it, such as Terebratulina gracilis, T. Gisei, Pentacrinus Agassizi, and P. Bronni, to take well-marked and fairly plentiful forms. There could be no hesitation in selecting as the zone-fossil Terebratulina gracilis if it were not for the unfortunate but universal misapplica- tion of this specific name to the characteristic fossil of the upper zone of the Middle Chalk. T. Gisez, considered by itself as a possible zone-fossil, is too small to be found with certainty, even if abundant, and it is hardly that. But 7. gracilis is such an ideal zone-fossil that I propose to remove the objection to it stated above by naming the Trimmingham Chalk “zone of Terebratulina gracilis and T. Giset,” or, for familiar use, “zone of Terebratulina,” it being understood that 7’. Gisei is not conclusive when occurring by itself, but that T. gracilis is. Pentacrinus Agassizi and P. Bronni could, of course, be used to characterise a “‘ zone of Pentacrinus,” but that would create great difficulty with the chalk of the erratics between Overstrand and Sidestrand, a part of the cliff which is unfortunately being ruined for geological observation by sloping and path-making operations. Before the era of sloping set in these erratics were about ten in number, and all (with one exception) lay on a thick bed of boulder-clay, which ran with great regularity at a practically unvarying height above the beach from the Overstrand breakwater to the grounds of the new hotel at Sidestrand. My attention was first drawn to these erratics by Miss Mary Townsend, of Oatlands Park, Weybridge, who happened to be staying at Overstrand in 1896, at a time when a storm had swept away the sand on the beach and exposed a great number of chalk boulders, no doubt all that had fallen from above for some years. I had then just become keenly interested in the Chalk of the Norfolk coast, and she, being aware of this, picked out for me all the fossils she could with a penknife, including a perfect Micraster cor-anguinum of the typical Norwich shape, a very creditable performance for a lady with no previous experience of fossils and armed only with a penknife. I have on several occasions been able to add to this collection, the salient points of which are the presence of Rhynchonella Reedensis, which occurs freely in the Cromer Chalk but not at all at Trimmingham, and the abundance of a Pentacrinus which is neither Agassizi nor Bronni, and does not occur either at Trimmingham or in the Cromer Chalk. The occurrence of a Pentacrinus is a strong link to the Trimmingham Chalk with its abundance of Pentacrinus, and this association is strengthened by the character of the chalk itself, which is often white, much mottled with blue-grey patches, just like so much of the white chalk at Trimmingham, and it is tempting to group this chalk with the Trimmingham Chalk rather than with the Cromer Chalk. At the same time the presence of R. Reedensis indicates that it is definitely older than the Trimmingham 16 R. M. Brydone—Further Notes on the Trimmingham Chalk. Chalk, and this is just what one would expect if, as is probable from their unaltered condition, these boulders are of quite local origin. The exception above mentioned was a large boulder, quite 30 feet high, immediately under the new hotel at Sidestrand. Unfortunately this was overlaid by a soft bed full of water, which kept its surface constantly obscured by a downwash of mud, and it was impossible to collect from it. It has now been destroyed in the sloping of the cliffs, or, if anything be left of it, it is turfed over and concealed for good. I did get from the foreman of the works a promise to let me know when they began to cut into the boulder, but the promise was not kept, and the operation was carried out in my absence, and a vaiuable opportunity thereby lost. One thing about it, however, was not entirely obscured by the mud, and that was the presence at about 4 feet from the base of a bed of laminated marl some 2 inches thick. This remarkable occurrence may mark the boundary between the zone of Terebratuling and the Cromer Chalk (which is decidedly identical in age with that now exposed near Norwich, and therefore belongs to the zone of B. mucronata). Some well-marked line of demarcation seems not unlikely. as there is a considerable paleonto- logical break. Not only Rh. Reedensis but also Zerebratula sexradiata are not uncommon in the Cromer Chalk, but still unknown at Trimmingham, and Micraster cor-anguinum, which is abundant (relatively speaking) in the Cromer Chalk, is so scarce at Trimmingham that I have not yet found a fragment of Micraster there, though Mr. Savin has two specimens, apparently from the hard basement bed. ‘There are also four very characteristic Upper Senonian Polyzoa, which in the South of England are found in the uppermost beds (with abundant specimens of Magas pumilus) of the B. mucronata zone, but which are not found at Trimmingham, though the environment there must have been so very favourable to Polyzoa that they might be fairly expected to occur there if they still persisted in the English seas. I have described and figured three cf these, which I cannot identify with published figures. It so happens that I have not yet recognised any of these three in the B. mucronata chalk of Norfolk, but the fourth, Membranipora (? Homalostega) clathrata, is abundant in the Cromer Chalk, and adds increased significance to the dis- appearance of Rh. Reedensis and Terebratula sexradiata. Under these circumstances I should be very chary at present of adopting a zonal description of the Trimmingham Chalk which would allow of the Sidestrand erratics containing Rh. Reedensis being included with it. Of course, if the great erratic was representative of the cliff from which the other erratics were derived, it would be quite conceivable that the marl band should be the boundary of the two zones, and the mixture of Pentacrinus and Rh. Reedensis in the fossils obtained be due to the presence of boulders both from above and below the boundary. (Many puzzling records are probably due to an assemblage of fossils gathered from a section containing the boundary of two zones being regarded as a naturally contemporaneous series, and assigned to the more prominent of the two zones.) GEOL. MAG. 1906. Dee Wy WO WOOF, JRE Views of the Trimmingham Chalk Bluffs, Norfolk Coast. (To illustrate Mr. R. M. Brydone’s paper.) Il. R. M. Brydone—Further Notes on the Trimmingham Chalk. Should it ever be -ascertained that. there is a. point at which the forms above mentioned all disappear, that. point. may safely be taken. as the upper limit of the B. mucronata zone of Norfolk. [Ido not say ‘Norwich Chalk,’ because I havea very strong opinion that that term is wholly unscientific... If it implies, as presumably it does, that all the chalk which has ever been exposed within two or three miles of Norwich is of the same zone, that,zone must be the zone of B. mucronata, and the term ‘Norwich Chalk’ is a mere synonym. It is undoubtedly the fact that the sections now accessible (Trowse, Thorpe, and Whitlingham) are all in chalk which contains 4. mucro- nata freely, and cannot on any pretext be assigned to any other zone.: But many of the fossils recorded from the ‘ Norwich Chalk,’ e.g. the Cephalopoda, seem decidedly unlikely, to occur in such chalk as that now exposed, and probably: the chalk in which. Baculites was, abundant was very different stuff from that now to be seen. In that case the ‘Norwich Chalk’ is a ‘hotchpotch’ of an unknown number of zones which should, with its so-called fauna, be discarded as'soon as possible in all attempts at zonal classification. I have really very’ little doubt as to the danger involved in treating the Norwich Chalk: as a zonal unit, and many of the peculiar species would: probably find a‘ place as synonyms if Samuel: Woodward’s types could be: found. Some can be so treated from the plates; e.g., Serpula: accumulata is almost certainly a synonym of S. vortex, S. pentangulata of S. canteriata, S.. carinata of S..fluctuata, S. contracta of S. gordialis (if Professor Deecke rightly identified the specimens to which: he. assigned the latter name, which has: not been very freely admitted by other collectors), and Plagiostoma granulosum of Lima granulata,. At any rate; we are not warranted by any accessible information in taking it for granted that the recorded fauna of the ‘ Norwich Chalk’ has been derived from pits exclusively in the same zone. _ Most. of the pits named are now inaccessible and ‘cannot be re-examined. | Unfortunately, in discussing the limits of the zones of the Upper Chalk in Norfolk we get very little assistance from the nearest area in which those zones occur again at all freely, i.e. in Sussex and. Hants. The zone of B. quadrata south of the Thames is often very fossiliferous, and the zone of B. mucronata is often: even more so, both zones being conspicuous for abundance of free-.: growing Polyzoa.. But in Norfolk, and indeed generally on the north of the Thames, both these zones are much less fossiliferous and practically devoid of free- growing Polyzoa. In fact, they present quite a different aspect; they are much more uniform and : much finer apparently in texture. . It may be only due to increased: depth, but ! have always felt tempted to postulate. the existence in. the Cretaceous sea of a submerged ridge separating the two areas. or. basins. The connection of the Norfolk. area with the Riigen sea,. which is so marked in the Trimmingham Polyzoa, must, have existed at least. as early as the age of the chalk round Norwich, and near’. Cromer, in which Homalostega pavonia, described from Riigen in 1839 but, not recorded from, any other locality except Trimmingham, . is quite abundant. Though Polyzoa are abundant at the top. of the DECADE Y.—VOL. III.—NO. I. 2 18 R&R. MW. Brydone—Further Notes on the Trimmingham Chalk. B. mucronata chalk of Hampshire, I have not yet found any Riigen forms there, and this may well be more than a mere coincidence. STRATIGRAPHY. In this department I have to acknowledge my indebtedness to Mr. G. P. Bidder, who was staying at Mundesley during late September and October of 1905, a time of very rough weather and great variety of exposures. Though not a geologist, he took great interest in the local geology and gave me much assistance in many ways. Amongst other things he pointed out to me that in my previous pamphlet I had overlooked the fact that the magnetic north is about 20° west of true north, and that I ought to mention that all my bearings were magnetic. I have, for convenience, continued to use magnetic bearings in this paper. South Bluff. Very little further development has taken place here, but the accuracy of the partly hypothetical presentation of the low southern prolongation in fig. 2 of my previous pamphlet has been established by fuller exposures both as to the continuity of the flint lines and their identification with those to the right of AB. It also turned out that at the furthest point to which they are shown extending they bend sharply down, and all but the highest of the lines shown to the right of A B come in on the slope. The highest of these was found to be dipping at quite 75° almost due south. (This very high dip on the south side of a ridge is by no means uncommon elsewhere in this area.) A great number of cavities have recently appeared in the upper beds of the southern part of the bluff, and it appears as if these cavities expand as they penetrate the bluff. This is just what would be expected if they were cavities formed in a cliff facing to the south or south-west, and tends to confirm the view that this part of the bluff, at any rate, is the remains of a headland which faced a sea lying to the south or south-west. A good deal of the sand in the gap between the two parts of the bluff has been cleared away and the south-easterly face of the northern part exposed to a point directly behind and on the same level as the northern end of the southern part and only 8 yards away from it (Plate II, Fig. 1). The marked difference in the physical characters of the two parts remains unaffected, and the conclusion that they are separated by a fault seems now inevitable if the north part is not an erratic, as to which no further evidence has been obtained. I have found a single specimen of O. lunata in the northern part. North Bluff: Here there have been some most interesting developments owing to the rapid erosion which has taken place, and is still proceeding. A great deal of erosion took place in the Winter of 1900-1 all round the bluff, and I was fortunate enough to obtain through Mr. Savin, of Cromer, the assistance of a local amateur photographer, R. M. Brydone—Further Notes on the Trimmingham Chalk. 19 who took in February, 1901, the photographs reproduced as Plate II, Figs. 2 and 3, and Plate III, Figs. 4 and 5. Fig. 2 shows the bluff as seen from a point on a line drawn through the bluff parallel with the beach-line. It will be noticed that one of the lines of flints appears to be vertical. That this is an illusion can be seen from Fig. 3, which was taken from a point approximately on the strike of the same line of flints, which (as I stated in my previous pamphlet, and have several times since checked) is not parallel to the beach-line. The appearance of verticality is due to the surface presented being oblique both to the line of vision and to the horizontal plane. Fig. 4, Plate III, shows a very interesting development on the north side of the bluff. A deep bay had been hollowed out with a long south side and very short north side. The south side was formed by first the bluff itself and then chalky clay, as shown in fig. 1 of my previous pamphlet. But the clay now proved to be only a narrow triangular mass, succeeded by a sloping bank of chalk which formed the rest of that side of the bay. The head of the bay was formed of talus from the cliffs above, and apparently concealing the connection of the sloping bank of chalk with the chalk which emerged again to form the short north side. This north side ended in a clean-cut cross section, which showed it to consist of a layer of chalk from two to three feet thick resting on chalky clay with an apparent bedding parallel to the base of the chalk, the junction plane dipping seawards at an angle of about 55°. The whole of the chalk exposed behind the triangular mass of clay was grey, and exhibited many peculiarities which will be dealt with fully later on. Fig. 5, Plate III, gives a close view of the pinnacle of clay and its immediate surroundings, and there are a number of points of interest about it. One is the distance from which the clay runs in under the chalk on either side. Shortly before the photograph was taken the sand was still further cleared away and the clay extended quite two feet further under the bluff. In this connection it is to be observed that a junction between the chalk and the clay has been seen on the foreshore close by for a distance of some 380 yards, throughout the whole of which the clay is running in under the chalk for a distance of at least nine inches, and may, for all appearances, underlie it altogether. There are many other points on the foreshore where the junction of chalk and clay has been observed, and in all the plane of junction is either vertical or else almost horizontal with the clay running under the chalk. Again, in the case of a fault on the foreshore almost opposite the north bluff, the chalk on either side of the fault has at one point been broken away so as to form a long narrow steep-sided pool about 18 inches deep. The bottom of this pool is formed by what appears to be the truncated top of a dome of clay, composed of fairly regular concentric layers of clay of varying colours, suggesting very strongly that the clay has been forced up from beneath into a cavity or crack. The point at which this occurs is at least 30 yards from the nearest exposure of clay. 20 R&R. M. Brydone—Further Notes on the Trimmingham Chalk. Another point is the pseudo-stratification of the clay roughly parallel to the sides of the fissure. This point is not well brought out by the photograph, in which it only appears by the light-coloured band. It was, however, much more apparent to the eye, being more or less marked all through the mass owing to slight variations in colour of the different bands, a reproduction of which is hardly to be expected by photography. Here again we have appearances strongly suggesting that a pseudo-stratified mass of clay has been forced upwards into a cavity. Another point which is not clearly shown by the photographs, is that the face presented by Fig. 4 was an almost plane surface apparently representing a clean section through the bluff, the clay and a homogeneous mass of grey chalk at the back. A fourth point which cannot, owing to the shadow, be distinguished at all in the photographs, is that there was a slender arch of chalk not more than two feet thick extending over the clay pinnacle and connecting the bluff with the chalk behind. I was only just able to reach the arch and ascertain that Ostrea lunata occurred in it. The seaward face of the bluff was at this time too steep to climb with any comfort, and the highest chalk which could be reached. from the beach was normal O. lunata chalk, which apparently continued up to the point where the nature of the chalk was completely obscured by dirt. Since the Spring of 1901 there has been steady denudation at this point. Unfortunately I was not able to obtain any photographic record until the Autumn of 1904, but the course of denudation in the meanwhile may be summarized as follows :— 1. The Original Bluff. The top of the bluff remained inaccessible and obscured by sand for some time. It became gradually cleaner and more accessible, but during 1901 I found nothing but 0. lunata chalk exposed. By 1902 the downwash of mud had practically ceased and the face of the bluff had been considerably stepped, and it was gradually revealed that the bluff was capped by a bed of grey chalk of a fairly uniform thickness of two feet and with a perfectly clean-cut boundary between it and the O. lunata chalk. (As this grey chalk will be referred to again later on, I take this opportunity of saying that its appearance is sometimes only to be detected by the change in colour. But, as a rule, it is separated from the 0. lunata chalk which is invariably found beneath it by an exceedingly thin seam of fine grit, containing scattered flint pebbles of various sizes up to that of a good-sized potato. In places this seam swells out into a definite bed as much as two inches thick containing small rolled pieces of chalk. The presence of rolled flints has not to my knowledge been before recorded in the English or, indeed, any Chalk. It throws an important light on the time of consolidation of the flints, which must have taken place in this case almost simultaneously with the deposition of the Chalk in which they were formed.) The grey chalk was plainly unconformable to the O. lunata chalk below, R. M. Brydone—Further Notes on the Trimmingham Chalk. 21 for the three upper lines of flint shown in fig. 1 of my previous pamphlet ran steadily and strongly up to the grit seam at the base of the grey chalk, and were then cut off by it. A fairly accurate representation of this state of things can be got by adding to the last-mentioned figure two feet of chalk resting horizontally on the truncated ends of the lines of flint. As the bluff was cut back these lines of flint sank, and after a time the lowest came wholly below the base of the grey chalk and formed a perfect arch. 2. The Fissure and its immediate surroundings. The triangular mass of clay filling the fissure was denuded much more rapidly than the chalk, and soon there was produced a definite inlet between two faces of chalk, which gave partial cross-sections of the masses of chalk. It became almost at once apparent that the grey chalk was really only a thin coating (thicker at the top and bottom on the slope than in the middle, but nowhere more than 18 inches thick) of a sloping surface of O. lunata chalk. The filling of the gap by clay proved in places to be incomplete, so that a considerable space was left between the top of the clay and the chalk arch, indicating that the clay was either very slightly fluid or not under great pressure when forced in. The latter cause seems the more probable, as if there had been great pressure at this point it is hardly possible that an arch of chalk, with a maximum thickness of two feet, should have remained unbroken. ‘The grey chalk soon appeared in the arch forming the upper part of it in a gradually increasing proportion and connecting the grey chalk on the bluff with that on the ‘slope,’ but it never completely cut out the O. lunata chalk which still formed the lower six inches or so when it was destroyed by the waves. About two-thirds of the way up the slope, was one of the points where the grit seam swelled out into a regular bed with pebbles and rolled chalk. 3. The Bay of Grey Chalk. The first event was the removal of the talus at the head of the bay and the exposure of a continuous surface of grey chalk beneath it. Then the grey chalk became thinner and finally disappeared altogether, both at the head of the bay and along the median (horizontal) line of the ‘slope.’ But while in the latter case the underlying stratum was O. lunata chalk, as might be expected, in the former case it proved to be clay similar to that at the back of the bluff. Further denudation of the grey clay exposed at a number of points O. lunata chalk coming in between the grey chalk and the clay as the edge of the grey chalk shrank back from the cliff (Pl. IV, Fig. 9). 4, The Bay on the South of the Bluff. This is but poorly shown in our Pl. II, Fig. 2, which was taken at a time when there was no particular feature of interest in the south bay. It only offered a section through the bluff and a mass 22 T. F. Jamieson—Raised Beaches of Scotland. of clay immediately behind it, and behind and above both a tumbled mass of glacial beds, separated from the chalk by a thin layer of dark laminated clay. | %° HEAD.OF BAY SEAWARD -\ FACE OF CLAY CHALK - Diagram of Chalk Bluff, showing the mass of clay immediately behind it and the SPL bs discontinuous line of chalk masses round the Bay. Towards the end of 1903 the grey bed which had been exposed at the top of the bluff began to throw out a ‘stringer’ (or, broken horizontal line of grey chalk) over the mass of clay behind it, and early in 1904 there was a discontinuous line of chalk masses visible for a considerable way round the bay. They were apparently supported by a mass of clay, which was turned under itself against the bluff, judging from the banding of the clay as sketched very roughly in the above diagram. ; EXPLANATION OF PLATES. Views of Trimmingham Chalk Bluffs, Norfolk Coast. Prate II. Fic. 1.—South Bluff; gap between northern and southern part. a, a, masses of . coarse shingle. Figs. 2 and 3.—Two views of North Bluff as seen from the south (1901). Puare ITT. - Fic. 4.—North Bluff; view of north bay (January, 1901). », 5.—Pinnacle of clay’ separating the North Bluff from the chalk at the back of it (January, 1901).' The connecting roof of chalk is‘in' deep shadow, and therefore very indistinct. se », 6.—View of the North Bluff and the exposure of chalk in the bay (November, 1904). ) (To be continued.) IJI.—On tHe Ratsep Beacues or THE GEroLoGicAL SurvEY oF , ScorTLanD. By LiF: JAMIESON, F.G.S. I the maps and memoirs of the Geological Survey of Scotland there is frequent mention of raised beaches at 50 and 100 feet above the present sea-level. Mr. James Geikie, too, in his well-known book on the Great Ice Age, confidently assumes the existence of beaches at these two levels. It is therefore with some degree of reluctance that in the following remarks I venture to question the reality of these supposed beaches; but it will lessen the field of controversy if I confine my observations to the east side of pound. Matters may probably differ somewhat in regard to the west side. re Wy ee 7 : GEOL. MAG, 1906. Deg, We Wo, JUUL, 1A, 1006 ee aoc eee tape Views of the Trimmingham Chalk Bluffs, Norfolk Coast. (To illustrate Mr. R. M. Brydone’s paper. ) iy Me lv # vi ‘ 4 4 i oe y T. F. Jamieson— Raised Beaches of Scotland. 23 In a paper on the last stage of the Glacial period in the Quart. Journ. Geol. Soc., 1874 (vol. xxx, p. 837), I maintained that subsequent to the last great glaciation of Scotland no sub- mergence of the country has taken place beyond that slight change of level which is marked by the estuary beds and raised beaches a little above the present coastline. Along the shores of the Firth of Forth this change of level does not seem to me to have been more than about 30 feet. Such was also the opinion of Charles Maclaren, a careful and accurate observer, who spent a long life in that locality and knew it well. At the Firth of Tay the amount does not seem to be any greater, and on going farther north the change of level appears to me to become less. At Montrose, for example, it does not seem to exceed 15 or at most 20 feet. Between Montrose and Bervie the raised beach is well marked in many places, but I could see no trace whatever of any higher ones at 50 or 100 feet. On reaching Aberdeen the height is still less, apparently not more than eight or ten feet along the coast of that county, nor does it seem to be any more on the Banffshire coast. In the estuary of the Ythan, half-way between Aberdeen and Peterhead, the change of level can be well estimated and does not appear to exceed what I have stated. I have examined that locality carefully and repeatedly, but have never been able to perceive the least sign of a raised beach at either 50 or 100 feet. In the valley of the Forth the old estuary-mud, or carse land, extends west a long way past Stirling, up to near the Loch of Menteith and Gartmore, rising gradually as we follow it inland to a level of 40 or 45 feet. This gradual rise seems to be always the case with a tidal mud as we trace it inland. The tidal wave rises often considerably in moving up a valley, as we see on the Severn at the present day. The fact of the carse land and alluvial loam of the Forth rising to 40 or even 50 feet at its inland extremity does not therefore imply a raised beach of that height at the coast. The Loch of Menteith is bordered by a fine group of old moraines which come down to the level of the carse, the lake itself being only 55 feet above the sea. These moraines were left during the retreat of the last great mantle of ice. Now, if there had been any subsequent submergence to the extent of 100 feet, it could not fail to have left its mark on the front of these moraines. The absence of anything of the sort is, I think, a proof that no such submergence has taken place. The basin of the lake should also have been filled with marine silt, of which there is no trace. At Aberdeen we have moraines which come down close to the present beach, as for example at the Broadhill on the east side of the ‘town. This Broadhill is one of the moraine heaps left by the glacier of the Dee during the last great extension of the ice. It is 94 feet high, and has been truncated apparently to some degree, or cut into, along its seaward side by the raised beach, but we look in vain for any evidence of sea-action upon it higher than a few feet above the present reach of spring tides. At Belhelvie, a few miles north of Aberdeen, we have another group of gravelly moraines left by the 24 T. F. Jamieson— Raised Beaches of Scotland. glacier when it reached the coast. A submergence to the extent of 100 feet should surely have made some impression on these also. Jt was no small development of ice that brought the glacier of the Dee down to the coast when it left these moraines. During this last glaciation I believe the whole of Scotland was more or less covered with perennial snow and ice; but the ice was probably very thin in many places along the east side, where the thick streams descending from the Highland valleys had room to spread out freely. This would account for considerable portions of the older clay-beds having escaped destruction, and in point of fact some of these Belhelvie moraines overlie wasted masses of the clay. If there was a raised beach at 100 feet we ought to find beds of estuary-mud with its characteristic fossils in our wider valleys near the 100 feet contour-line, but where are they ? We hava such beds with shells and whale-skeletons in these valleys at heights corresponding to the real old beach whose existence I have mentioned ; but we have absolutely nothing of the sort corresponding to a submergence of 100 or even 50 feet. Is not this sufficient proof that there has been no such submergence? In Aberdeenshire the river Ythan (which enters the sea half-way between Aberdeen and - Peterhead) flows along a wide little valley with a very small gradient, so that a submergence to the extent of 50 feet would send the tide ten miles up it. That basin should have certainly been filled to some extent with estuary silt, but no trace of anything of the sort is to be seen beyond a few feet above the limit of spring tides. A like submergence in the valley of the Dee would have sent the tide six or seven miles up that river with a similar result, and a submergence to the extent of 100 feet would have sent it on a few miles further ; but no sign can be perceived of any such event having happened after the last glaciation which brought the Dee glacier down to the coast. Evidence of this sort could be multiplied along valleys on the east side of Scotland, but perhaps the above will suffice. It would surely be time enough to talk of a hundred feet beach when we could point to some beds of littoral shells at a corresponding height, taking care that no shell heaps of edible mollusks left by man were mistaken for the real article, because on the shores of our estuaries such heaps are often to be found. The notion of raised beaches at 50 and 100 feet seems to have arisen in 1879 in mapping Sheet 31 by the Geological Survey, for it is in the explanatory memoir of that sheet that we find this idea first brought forward, and ever since then it seems to have become a settled article of faith with the Scottish Survey. Beds of clay in the neighbourhood of Falkirk are described in that memoir having a flattish terraced aspect, which seems to have led to the belief that they were old beaches; but no good evidence, fossil or otherwise, is adduced to substantiate this opinion, and surely the mere flatness of a bed of clay is no sufficient proof that it is a beach. This clay was no doubt accumulated under water, possibly sea-water, but the evidence of denudation and disturbance which it shows in many places harmonizes better with the idea that it has been afterwards Dr. H. Woodward—Fossil Insect from Ooal-measures. 29 -exposed to the action of land-ice, which has moved over it with more or less damaging effect according to the thickness of that ice. We may consequently infer that the deposition of the clay took place previous to the last general glaciation. Such, it seems to me, is clearly the case with the red clay of Aberdeenshire, and the illustrations of disturbance in the beds at Portobello and elsewhere given by Mr. Geikie in his book convey the same impression. Moreover, such fossil evidence as these clays do present at Errol, Klie, Montrose, and other places points to deeper water than a submergence of even 100 feet would imply. I see no reason, therefore, to depart from my opinion that subsequent to the last general glaciation of Scotland there has been no submergence along the eastern side of that -country beyond what would be accounted for by a depression of the land, amounting to from about 30 feet on the Firth of Forth to 10 feet on the coast of Aberdeen. The history of the Glacial period has proved a difficult subject to unravel, and we have all made mistakes about it. It is therefore in no captious spirit that I have been led to make these strictures on the raised beaches, but rather with the view of promoting a better knowledge of this passage in the last geological changes which our country has undergone. Briefly, then, my reasons for disbelieving in the existence of these raised beaches at 50 and 100 feet on the east side of Scotland after ‘the last general glaciation of that country are :— 1. Because at and below these levels there are moraine heaps which show no evidence of sea-action on them up to such heights. 2. Because there is an absence of estuary-mud with its characteristic fossils in the valleys at levels where such a sub- mergence should have produced it. 3. Because there are no beds of littoral shells at levels ‘corresponding to such beaches. 4, Because the beds of clay supposed to have been formed during the time of the 100 feet beach contain remains of mollusca and starfishes, which indicate deeper water and an older stage of the Glacial period. 5. Because these clays also show evidence of having been wasted and disturbed by subsequent glacial action, and are therefore anterior to the last general glaciation. IV.—A Fosstz Insect FROM THE COAL-MEASURES OF LONGTON; Norta STAFFORDSHIRE. By Henry Woopwarp, LL.D., F.R.S., F.G.S. OME time since Mr. John T. Stobbs, F.G.S., obtained a very well-preserved impression in clay ironstone of the wing of a Neuropterous insect from the rich plant-bed at Foley, near Longton, North Staffordshire, which he very obligingly submitted to me for study. The geological horizon is that of the “ Peacock Marl” (i.e., the marl overlying the Peacock Coal), and it therefore -comes from near the top of the workable Coal-measures.* 1 See letter by Mr. John T. Stobbs in Gro. Maa., 1903, p. 524. 26 = Dr. H. Woodward—Fossil Insect from Coal-measures. The impression is that of the hinder wing of the left side of a Neuropterous insect, the wing being fully 5 cm. long and 2 cm. in breadth. The distal extremity is wanting, but from the scar left on the matrix the lost tip probably did not exceed 1 cm., and the point has been restored in dotted lines in the figure. At the point in the figure marked by a * the pinnule of a fern, Neuropteris, overlies the wing, but, for the sake of clearness, has been omitted from the drawing, and the nervures of the wing are continued by dotted lines over the obstacle; near the point of attachment to the body the structure of the wing is also obscured. For the convenience of description, small Roman numerals, marking the principal nervures, have been added to the figure of the wing (as used by Mr. Charles Brongniart).1_ The following is a brief description of the specimen as far as I am able to define it :— r I SEE ND Za WAS SC; o-=> Mc Fic. 1.—Left posterior wing of Lithomantis carbonarius (?), H. Woodw., from the Coal-measures, Foley, near Longton, North Staffordshire. I, the costal nervure; II, the sub-costal nervure; III, the radial nervure; V, the median nervure; VII, the cubital nervure; IX, etc., the anal or basal neryures. The costal nervure (I) is strong, and forms the anterior margin of the wing; it gives off no branch. It is connected with the sub-costal (II) by a series of very fine straight nervules.2, The costal and sub-costal converge distally at about two-thirds of their length from the body. The radius (III) runs in a parallel course for some distance from its commencement below the sub-costal, giving off a branch-nervure at III, s, one-third of its length, which, diverging rather more as it advances, is again subdivided at two-thirds of its length into three branches, the upper and middle ones subdividing again into two, and these into two more 1 «Recherches pour servir 4 l’histoire des Insectes Fossiles des temps Primaires,”’ etc., par Charles Brongniart ; St. Etienne (Théolier et Ci*), 1893. 4to; pp. 494, and Atlas, pp. 44, and 37 double 4to and folding plates. This accomplished naturalist, grandson of the celebrated botanist Adolphe Brongniart, died at the early age ot 40 on April 18th, 1899, having, even in so few years, achieved much splendid work in fossil entomology. (See Grou. Mac., 1900, p. 430.) 2 These fine straight nervules, not being easily seen, have not been shown by the artist in the above figure of the wing. Dr. H. Woodward—Fossil Insect from Coal-measures. 27 dichotomies before reaching the margin at III. The median nervure (V) commences singly at the base of the wing and gives off two branches; the upper one, curving slightly upwards, unites with the lower or third subdivision of III, s, and reaches the lower distal border at V; the lower branch subdivides into two, the upper nervure reaching the margin singly, the lower subdividing into two before ending about the middle or lower half of the posterior border; the cubitus (VII) is mostly hidden by the pinnule of a fern-leaf, but the direction it follows is indicated by a dotted line. It reaches the margin in two branches. Four anal or basal nervures follow, all of which are simple and have no dichotomies. Fie. 2.—Wing of Lithomantis (Corydalis) Brongniarti, Mantell, sp. Coal-measures : Coalbrookdale, Shropshire. I have already suggested! to the discoverer of this interesting specimen that it was probably nearly related to Lithomantis carbonarius, H. Woodward, figured and described by me (Quart. Journ. Geol. Soc., 1876, vol. xxxii, pp- 60-65, pl. ix, fig. 1) from the Coal-measures of Scotland, and also to the much earlier described wing of Lithomantis (Corydalis) Brongniarti (Audouin), G. A. Mantell, from Coalbrookdale. Ss x SS Fic. 3.—Lithomantis carbonarius, H. Woodw. Coal-measures: Scotland. One-third less than nat, size. In his great work on the “Histoire des Insectes Fossiles des temps Primaires” (1893), M. Charles Brongniart has figured and 1 Grou. Mae., 1903, p. 524. 28 Dr. H. Woodward—Fossil Insect from Coal-measures. described another fossil insect closely allied to the above, which he has there named Homoioptera Woodwardi [pl. xxxvi (20), fig. 10], but had originally described in 1890 (Bull. Soc. Philom. Paris, tome ii, pl. i) as Lithomantis Woodwardi, Brong. M. Brongniart. Fic. 4.—Hoimoioptera (Lithomantis) Woodwardi, Brong., 1890. Coal-measures: Commentry, France. One-half nat. size. however, justified the adoption of the later generic name Homoioptera, on the ground that he found the Commentry insect did not actually agree with the living Mantipz. But although they ought to be referred to different genera, they are not far removed from one another, and they both possess wing-like expansions on the prothorax. These forms, Lithomantis, Fouquea, Homoioptera, and thirteen other genera enumerated by M. Brongniart, are arranged by him under the family PLAryPrEripa. He considers all these insects to be Neuroptera in their general characters ; they attain to a large size, the smallest not being less than nine centimetres across the wings. ‘They are all extinct forms, the group to which they may best be compared being the EpHemMertip&. They differ in the character of the nervation of their wings; the radius is not simple, but more or less dichotomising, as well seen in our Fig. 1 (III); furthermore, the second pair of wings are larger and more developed than the first pair, which is not the case in living Ephemera. These insects, as is common with nearly all the fossil genera, are only known to us (as a rule) by their wings, their bodies and limbs being extremely rare, and seldom found complete in the Coal-measures or in other old deposits yielding fossil insects. It is doubtful whether the wing, now figured for the first time, from Mr. Stobbs’ collection, is specifically distinct from Lithomantis Prof. kh. Broom—Permian and Trias in South Africa. 29 carbonarius, but it is certainly important to record its discovery in the Staffordshire Coalfield. Fie. 5.—Wing of Fouguea cambrensis, n.sp., from the Coal-measures of South Wales. x2. Reproduced from Mr. H. A. Allen’s paper (see Grox. Mac., 1901, p. 66). It is very distinct in general form from Fouquea cambrensis, figured and described by Mr. H. A. Allen, F.G.8., from the Coal- measures of South Wales, but it certainly belongs to the same group as Lithomantis and to the family PLatyprERipa. V.—On tHe Permian anp Triassic Favnas or SourH AFrica. By Professor R. Broom, M.D., D.Sc., Victoria College, Stellenbosch. NTIL recently very little attempt has been made to classify the reptilian fossils of the Karroo Beds according to their geological horizons. Seeley recognised certain zones—(1) the zone of Mesosaurs, (2) the zone of Pareiasaurs, (3) the zone of Dicynodonts, (4) the zone of specialised Theriodonts, and (5) the zone of Zanclodonts. While the order of these zones is correctly given they do not cover the whole period, and the third zone is an unnatural one. As the result of the work of the last few years, it is now possible to subdivide the Karroo Beds with some degree of accuracy into a number of fairly well-marked distinct faunas. At the recent meeting of the British Association a paper was read, which will appear elsewhere, giving the details of recent work. As, however, much interest is at present being taken in the Triassic faunas of both Kurope and America, a summary of the conclusions come to may be of use to workers in the northern hemisphere. The most recent rocks of the Karroo Series are the Upper Stormberg Beds. These contain remains of the Dinosaurs Masso- spondylus, Huskelesaurus, and Hortulotarsus, and of the small crocodile Notochampsa. As Notochampsa is a true crocodile, we may safely refer the beds to Lower Jurassic, more especially as the Lower Stormberg or Molteno Beds immediately below have been referred by Seward from the evidence of the plant remains to the Rheetic. Below the Molteno Beds we come to the Cynognathus Beds, corresponding to the ‘specialised Theriodont’ zone of Seeley. In 30 = =Prof. R. Broom—Permian and Trias in South Africa. these beds there is a very rich fauna, of which the most characteristic forms are the extremely mammal-like Cynodont reptiles, Cynognathus, Gomphognathus, etc. Other noteworthy forms are the large Phyto- saur, Erythrosuchus; the Gnathodont, Howesia, a small form allied to Hyperodapedon; a species of Cyclotosaurus, and a species of Ceratodus. There seems little doubt that these beds are of Upper Triassic age. Underneath these we come to a distinct but allied fauna charac- terised by the abundant remains of the primitive reptile Procolophon. Other forms are Paliguana, the oldest known true lizard, and Proterosuchus, a Rhynchocephalian which shows some affinity to the Phytosaurs. These beds are called the Procolophon Beds, and may be of Middle Triassic age. Below these are extensive beds in which land forms are very rare, but in which are abundant remains of the aquatic Anomodont, Lystro- saurus, and the fish Atherstonia. These are called the Lystrosaurus Beds, and they are believed to be of Lower Triassic age. Underneath these Lystrosaurus Beds we come to rocks in which land forms are again numerous. ‘Three fairly well-marked zones are recognised: (1) Kistecephalus Beds, (2) Endothiodon Beds, © (3) Pareiasaurus Beds. In all of these remains of Dicynodon are met with, but it is in the Hndothiodon Beds that Dicynodon and Oudenodon are met with in greatest abundance. All the carnivorous reptiles of this period are either Therocephalians or Dinocephalians. All three zones are believed to be of Upper Permian age. Below the Pareiasaurus Beds a few reptiles have been found in the Ecca Beds, but most of the remains are very imperfect. Meso- saurus is found in the Upper Dwyka, and may be assumed to be of Lower Permian age. While it is perhaps unwise to place too much weight on the evidence, the South African faunas seem to afford a little new light on the age of the Elgin sandstones. The Stagonolepis Beds, which contain Stagonolepis, Ornithosuchus, Erpetosuchus, Stenometopon, Hyperodapedon, and Telerpeton, seem to correspond to the Cynognathus Beds of South Africa, which contain Erythrosuchus, Howesia, and Thelegnathus, forms all allied to those of Elgin. If this be so, then the Stagonolepis Beds may be regarded as Upper Triassic. The Gordonia Beds, containing Gordonia, Geikia, and Elginia, resemble most closely the Pareiasaurus Beds of South Africa with Dicynodon, Oudenodon, and Pareiasaurus. The resemblance, how- ever, is much closer to the Russian forms of the Upper Permian of the Dwina, and it seems probable that the Elgin forms are descendants of the Russian, as the Russian probably are of the African. We may conclude that the Gordonia Beds are either Upper Permian or Lower Triassic, more probably the former. (See also Abstract of paper by Prof. Broom on the Classification of the Karroo,Beds of South Africa, p. 36.) C. Davies Sherborn—Irreguiar Chalk Echinoids. ol ViI.—Remarks on tue IrRrRecuLtaAR Ecutnoips or tHe WHITE CHALK or ENGLAND AS EXHIBITED IN THE British Museum (NaruraL History). By C. Davizs Suerzorn, F.G.S. AVING been asked by Dr. Smith Woodward and Dr. Bather to look over the collection of Irregular Echinoids from the English Chalk in the British Museum with a view to bringing the exhibition up to date, it appears a favourable opportunity to say a few words as to the nomenclature and distribution of these animals. Until Dr. A. W. Rowe has completed his study and given us the result of his examination of his own splendid collections, it is im- possible to give more than a brief outline of the subject, for he, and he alone, has the material necessary for a detailed report. The bulk of the material in our National Collection has been acquired by donation or purchase, and that at a time when zones or localities were considered of little importance, whereas Dr. Rowe’s material has all been collected by two persons, with the definite object of showing the evolution of the animals and the resulting progressive change into forms of more or less value. While, therefore, the National Collection is invaluable from a zoological point of view, it is practically valueless for Hvolutional Palzozoology. The present exhibit has been obtained by the help of others, and the authorities have to thank Messrs. Bather, Chatwin, Dibley, Rowe, Sherborn, and Withers for specimens which show more or less completely the history of each species as it is followed successively upward in the zones of the White Chalk of this country. It has not been possible to acquire specimens from each zonal occurrence of the rarer species. I will take the forms seriatim, making such notes as seem necessary as I proceed :— Echinocorys scutatus, Leske: Addit. ad Klein, Nat. Dispos. Echin., 1778, p. 175, pl. xv, figs. a, B. This is the earliest name for this urchin. lLeske does not say where the type came from, but it is a cor-anguinum form. 'The synonyms of this species are F. ovatus, Leske, Addit. ad Klein, etc., p. 178; . vulgaris, Orbigny (ew Breyn), Pal. Frane. (Cret. Ech.), 1854, p. 62, pls. 805, 806. Range: H. planus zone to Danian. ‘Conulus albogalerus, Leske: Addit. ad Klein, Nat. Dispos. Kchin., 1778, p. 162, pl. xili, figs. a, B. This is the earliest name for this urchin. Leske does not say where his type came from, but it is a somewhat low (depressed) form from the cor- anguinum zone. The synonyms are Galerites albogalerus (Leske), Lamarck, Anim. sans Vert., iii, 1816, p. 20, and Echinoconus conicus, Orbigny (es Breyn), Pal. Frang. (Oret. Kch.), 1860, p. 515, pl. 996. Range: M. cor-testudinarium to A. quadratus zones. Conulus orbignyanus (Ag.). Galerites orbignyana, Agassiz, Mon. Kch. (Galerites), 1842, p, 22, pl. iii, figs. 5-8. This is the little bun-shaped Conulus found at Trimingham and in (?) the upper o2 C. Davies Sherborn—Ilrregular Chalk Echinoids. part of the mucronata zone at Norwich. Brydone, in his: “Stratigraphy and Fauna of the Trimmingham Chalk,” 1900, p. 12, refers this to ‘ Hchinoconus (abbreviatus ?),’ but Dr. Bather has carefully gone into the matter with me and agrees that the determination with orbignyanus of Agassiz is correct. Range: (?) upper part of &. mucronata zone and the Danian Chalk of Trimingham. Conulus globulus (Desor). Galerites globulus, Desor [non Leske], Mon. Kchin. (Galerites), 1842, p. 18, pl. iv, figs. 1-4. Range : Marsupites zone. Conulus subrotundus, Mantell: Geol. Sussex, 1822, p. 191, pl. xvii, figs. 15-18. Range: Z. gracilis and R. cuvieri zones. Conulus castaneus (Brongniart). Nucleolites castaneus, Brongniart, Géol. environs Paris, 1822. pl. ix, fig. 14. Range: T. gracilis and ft. cuvieri zones. Discoidea dixonit, Forbes. Galerites (Discoidea) dixzoni, Forbes, in Dixon, Geol. Sussex, 1850, p. 341, pl. xxiv, figs. 138,14. Range: R. cuviert to H. planus (1 example) zones. Micraster cor-anguinum (Leske). Spatangus cor-anguinum, Leske, Addit. ad Klein, Nat. Dispos. Echin., 1778, p. 221, pl. xxiii, fig. c (anglicum). Range: Jd. cor-anguinum to B. mucronata zones. Micraster cor-testudinarium (Goldfuss). Spatangus cor-testudinarium, Goldfuss, Petref. German., 1829, p. 156, pl. xlviii, fig. 5. Range: H. planus to base of IL. cor-anguinum zones. Micraster precursor, Rowe: Quart. Journ. Geol. Soc., vol. lv (1899), p- 5380. Range: top of T. gracilis (1 example) to base of M. cor-anguinum zones. Micraster leskei (Des Moulins). Spatangus leskei, Des Moulins, Etudes Echin., 1857, pt. 3, p. 392. Range: BR. cuviert to H. planus zones. Micraster cor-bovis, Forbes: in Dixon, Geol. Sussex, Ist ed., 1850, p. 342, pl. xxiv, figs. 3, 4. Range: R. cuvieri to base of M. cor-testudinarium (2 examples) zones. Epiaster gibbus (Lamarck). Spatangus gibbus, Lamarck, Anim. sans Vert., ili, 1816, p. 58. Range: M. cor-testudinarium (1 example) to Marsupites, and B. mucronata zones. Infulaster excentricus (Rose). Spatangus excentricus, C. B. Rose, in Woodward, Geol. Norfolk, 1833, p. 37, pl. i, fig. 5. Range: M. cor-anguinum to B. mucronata zones (teste Cret. Rocks Brit., iii, Mem. Geol. Surv., 1904, p. 500). Recorded by Burnet (Grou. Mac., 1904, p. 175) from the Holaster planus zone of Lincolnshire. The type came from the Norwich gravels. Only known to Rowe and myself from the J/. cor-anguinum zone ; not seen from DMarsupites or A. quadratus zones; not in the Fitch Collection, and not found by us in the B. mucronata zone at Norwich or elsewhere. If a specimen were found below the MM. cor-anguinum zone, we should suspect it to be Cardiaster cotteauanus, but the material yet known is not sufficient to work out the relationships and differences of these two forms. U. Green & C. D. Sherborn—Silurian Fossils, Cornwall. 38 Hagenowia rostrata (Forbes). Cardiaster rostratus, Forbes, Fig. Brit. Org. Rem., Mem. Geol. Surv. U.K., dec. iv, 1852, p. 3, pl. x. Infulaster rostratus, Wright: Pal. Soc. (Cret. Hch.), 1881, p. 807. Hagenowia rostratius, Duncan: Journ. Linn. Soc. (Zool.), xxiii, 1889, p. 211. Range: WM. cor-testudinariwn (1 example, Yorkshire) to 4. quadratus zones. Hemiaster minimus (Agassiz). Micraster minimus, Agassiz, Hchin. Suisse, i, 1839, p. 26, pl. iii, figs. 16-18. Range: R. cuviert to M. cor-testudinarium zones. Holaster planus (Mantell). Spatangus planus, Mantell, Geol. Sussex, 1822, p. 192, pl. xvii, figs. 9 and 21. Range: top of BR. cuviert (1 specimen) to base of M. cor-testudinarium zones. Holaster placenta, Agassiz : Cat. Syst. Ect. Kch., 1840, p. 1; Modele 2 ; Ann. Sci. Nat. (3), viii, 1847, p. 27. Range: top of BR. cuviert (1 specimen) to A. quadratus zones. Very rare except in the Micraster zones. Cardiaster ananchytis (Leske). Spatangus ananchytis, Leske, Addit. ad Klein, Nat. Dispos. Hchin., 1778, p. 248, pl. liii, figs. 1, 2. Range: JL. cor-anguinum (1 specimen) to Danian. Common in quadratus chalk, Yorkshire; common in mucronata chalk, Norwich. Cardiaster pygmeus, Forbes : Ann. Mag. Nat. Hist. (2), vi, 1850, p. 444 (name only); Forbes, Fig. Brit. Org. Rem., Mem. Geol. Surv. U.K., dec. iv, 1852, p. 4. Range: R. cuviert zone. Cardiaster cotteauanus, Orbigny: Pal. Frang. (Cret. Hch.), 1855, p. 140, pl. 880. Range: H. planus and JM. cor- testudinarium zones. Cardiaster cretaceus (Sorignet). Holaster cretaceus, Sorignet, Oursins fossiles Eure, 1850, p.69. Range: fh. cuviert and T. gracilis zones. Offaster pilula (Lamarck). Ananchytes pillula (sic), Lamarck, Anim. sans Vert., ili, 1816, p.27. Range: Marsupites (2 or 3 known), A. quadratus zone (common) ; known from B. mucronata zone. The information as to range has been obtained from Rowe and Sherborn’s papers on the White Chalk in the Proc. Geol. Assoc., 1900-1904 (see Index to, etc, idem, vol. xviii, pt. 7, 1904, pp. 375-884), and Dr. Rowe’s unpublished notes; and the exact distribution and history of the genus Micraster can be seen in Quart. Journ. Geol. Soc., vol. lv (1899), pp. 494-546. I have received much assistance from Dr. Bather during the progress of this work. VII.—Lists or WeENtOocKIAN Fossits FRoM PortHLUNEY, CoRNWALL ; Luptow1an Fossirs From PortHauta; and Taunustan Fossius FROM PotyneE QuaRRy, NEAR Looz, CorNwWALL. By Urrietp Green, F.G.S., and C. Davies Suerzorn, F.G.S. EF the Autumn of 1904 we had the good fortune to find in the “Slates with inclusions” at Porthluney, near Gorran, Cornwall, a lenticle of limestone which has yielded a small but satis- factory series of forms allowing its reference to the Wenlockian beds. DECADE V.—VOL. III.—NO. I. 3 34 U. Green & C. D. Sherborn—Silurian Fossils, Cornwall. In the Grotocroan Magazine, July, 1904, p. 289, one of us had the pleasure of recording the occurrence of Ludlow fossils at this spot in the same beds, and that discovery renders the present one of additional interest. The fossils, which have been handed over to the Geological Survey, are as follows :— Ptilodictya lanceolata, Lonsd. Fenestella assimilis, Lonsd. Fenestella cf. B.M., D 571, from Wenlockian of Dudley. Fenestella sp. Millepora cf. repens (L.). Monticuliporid, ramifying through the whole mass of the lenticle. Rhynchotreta cuneata (Dalm.). Amphicelia striata (Sow.). Pterinea sp. In the Autumn of 1905 we again visited Porthalla, and after working three days found another fossil in the “Slates with inclusions” on the beach of Nare Cove. This was a pyritized Orthoceras comparable with O. bullatum, Sow., and O. virgatus, Sow., both of Ludlow age, and distinct from the forms found similarly mineralized in the Devonian beds, by reason of the casts of its siphuncular chambers being barrel-shaped instead of parallel-sided. It is preserved in the British Museum and registered as B.M., C 10529. Three days work at Polyne Quarry, in the Taunusian beds, yielded thousands of fossils. The bulk of these are in so bad a state that it is difficult to recognize even the genus, but careful collecting and a knowledge of the better specimens to be obtained in Germany render it a comparatively easy task to select sufficient identifiable examples. The following list shows the fossils obtained, the more interesting of which have been placed in the British Museum (Nat. Hist.) :— Fenestella. Pachypora. Petraia pauciradiata (Phillips). B.M., R 7502, 7508. Petraia celtica (Lamouroux). B.M., R 6079. Petraia radiata, Muenster. B.M., R 7496, 7561. Petraia punctatocrenulata, Roemer. B.M., R 6978. Petraia gigas, McCoy. B.M., R 2838, 618. Pleurodictyum problematicum, Goldfuss. B.M., R 6072, 6978. Lodanella mira, Kayser. B.M., P 7697. Neritopsis. A fine series, some showing a broad expanded mouth. B.M., A 1158-1160. Phacops ferdinandi, Kayser. Six quite typical eyes, one of which showed part of the head-shield. B.M., 172383, 7234. Strophodonta gigas, McCoy. Streptorhynchus. Athyris cf. undata, Defr. Rhynchonella. Renselleria. Notices of Memoirs—Papers read at British Association. 595 Orthis personata, Zeill. Orthis vulvaria, Schl. Orthis circularis, Sow. Spirifer primevus, Stein. Spirifer subcuspidatus, Schnur. Spirifer cf. hystericus, Schl. Crinoid columnars, some very large, # inch across. B.M., H 14062. The Zodanella, which was obtained by the last drive of the crow- bar, is magnificent and quite equal to the type-specimen. It is hoped that these lists will stir up others to search for fossils in this interesting area. We are much indebted to Mr. G. C. Crick and Mr. W. D. Lang, who have most carefully examined and helped us with some of our material. INP OQeEGILOAa S| | (Qagy “aAMEIsHIMi@ahisyS, Jaya. British ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. Meretine 1n Sour Arrica, Aucust 15TH To Spr. Isr, 1905. PAPERS READ BEFORE SEcTION OC, GEroLoGy. I..—On tHe RELATION BETWEEN ORE VEINS AND PEGMATITES. By Professor R. Brcx. HE author gave a summary of the latest investigations on the origin of pegmatites, by W. C. Brogger, H. Rosenbusch, S. Arrhenius, J. H. L. Vogt, U. Grubenmann, and others. In conformity with these authors, he explained pegmatites as products of crystallisation from the superheated water, which remained, after the consolidation of a plutonic magma, as a concentrated solution containing many of the rarer chemical elements and compounds formerly distributed through the whole fluid mass. Being retained in the depths of a plutonic focus under high pressure, these remains of magmatic water could pass through a very gradual process of cooling; whereas the so-called ‘juvenile’ thermal waters (Juvenile Quellen) of similar origin found their way to the upper parts of the earth’s crust, and caused there the formation of minerals at lower temperatures and pressures. Most ore veins belong to the second class, but a considerable number of occurrences may be styled metalliferous pegmatites. The best known examples of these are found in the group of tin ores, and as such were discussed the ore veins of Zimwald, Graupen, Embabaan, and others. As examples of copper ores were cited those of Telemarken in Norway ; and finally some gold-bearing quartz reefs were described which are very nearly related to pegmatites, and that not merely by their characteristic mineralogical composition (Berezowsk, Southern Appalachians, Yukon District, Passagem, and other instances in Brazil). It may be mentioned in proof of this that certain gold quartzes contain tourmaline, the characteristic mineral of all pegmatites. 36 Notices of Memoirs—Papers read at British Association. II.—Tue CLasstFication or THE Karroo Breps or SoutH AFRICA. By Professor R. Broom, M.D., B.Sc. i attempt is made from the study of fossil remains to give a more satisfactory subdivision of the Karroo System than has- hitherto been possible. The larger subdivision into the Dwyka, Eeca, Beaufort, and Stormberg Series is retained. The Beaufort Beds are divided into series. The lowest is. characterised by the presence of Therocephalians and Anomodonts. These lower beds can be again divided into an earlier series, in which occur Pareiosaurus and Titanosuchus, and a later series: characterised by the prevalence of Dicynodon and Oudenodon. Above the Lower Beaufort Beds occur a Middle series, characterised by the rarity of reptilian remains other than of Zystrosaurus, which is very abundant. The Upper Beaufort Beds are characterised by the presence of the Theriodonts. In the earlier subdivision of these upper beds. Procolophon is the most characteristic fossil, and in the upper the Theriodont Trirachodon. The Stormberg Beds appear to be divisible into two groups— a lower, the Molteno Beds, and an upper, which includes the Red Beds, the Cave Sandstone, and the Volcanic group. The Dwyka and Hcca Series are believed to represent the Lower and Middle Permian of Europe, and the Lower Beaufort Beds the Upper Permian. The Middle Beaufort and Upper Beaufort Beds are believed to correspond to the Lower and Upper Trias of Europe. The Stormberg Beds are believed to be Lower Jurassic or Rhetic, and the Upper Stormberg Beds Lower Jurassic. IlI.—Tue Stormperc Formation in tHe Oape Cotony. By Apex. L. pu Tort, B.A. \HE Stormberg Formation is the uppermost division of the Karroo System in South Africa, and builds up the whole of Basutoland and the adjoining portions of the Cape Colony, the Orange River Colony, and Natal. In the Cape Colony the tract occupied by this formation is confined to the immediate neighbourhood of the Drakensberg Range, widening out considerably in the south-west over what is known as the Stormberg area. The Stormberg series is subdivided as follows in downward succession :— (4) Volcanic Beds, (3) Cave Sandstone, (2) Red Beds, (1) Molteno Beds. The strata lie nearly horizontally, or are only inclined at low angles, consequently the lower divisions crop out along the foot of the mountain ranges, while the upper beds form all the higher ground. The Molteno Beds consist of a thickness of 1000-2000 feet of sandstones, with thin, dark shales and mudstones and occasional Notices of Memoirs—Papers read at British Association. 37 coal-seams. Arenaceous material is predominant, and the sandstones vary from fine-grained grey felspathic varieties to coarsely crystalline ‘ glittering’ sandstones, with small pebbles of vein-quartz. Boulders of hard white or brownish quartzite, derived evidently from the Cape Formation, are common, usually scattered irregularly throughout the sandstone beds, but occasionally forming conglomerate bands. The coals are thin, and contain from 15 to 30 per cent. of ash, but are the only workable deposits in the Cape Colony. Fossils are almost entirely those of plants, e.g., Thinnfeldia, Teniopteris, Callipteridium, ete., from which the Rheetic age of the beds has been deduced. The Red Beds are more argillaceous in character, and consist of 600-1600 feet of strata, in which red and purple shales, mudstones, and sandstones are predominant, though thick beds of fine-grained white sandstone are also common. Fossil remains are chiefly those of carnivorous Dinosaurs, such as Huskelesaurus and Massospondylus. The Cave Sandstone is a thick bed of fine-grained felspathic sandstone, usually white or yellowish in colour, and of very striking appearance. As a rule, it is unbedded throughout, except towards its summit, or less commonly towards its base. In some places it attains a thickness of 800 feet, but as a rule it varies from 150 to 390 feet. Ina few places the Cave Sandstone is entirely absent, and the volcanic beds rest directly upon the red beds. The Cave Sandstone weathers into most fantastic outlines, and gives rise to very peculiar scenery along the Drakensberg. The sediments of the Karroo System were deposited in a great inland sea, ‘the Karroo Lake,’ in which the water was either fresh or slightly brackish, and not very deep. During the formation of the Stormberg rocks the shore-line stretched where the coast ranges of the south of the Colony now rise, and extended eastwards into the Indian Ocean, and then north-eastwards parallel to the coastline of Natal. This old land surface was formed of rocks belonging to the Cape and Pre-Cape Systems, quartzites, granites, and metamorphic rocks. During Cave Sandstone times volcanoes came into existence, and great eruptions of basic lavas took place. Over 100 volcanic necks have been mapped by the Geological Survey, some of which are over a mile in diameter. Many of the pipes are filled with siliceous breccias, or with fine-grained sandstone-like tuffs. The erupted material consists almost entirely of basic lavas, compact to vesicular, the most interesting variety of the latter being the ‘ pipe-amygdaloid’; enstatite-andesites occur in a few places. Beds of volcanic ash are met with in Barkly Hast and around Jamestown. In the former district there are frequent alternations of lava, ash, and sandstone, the even bedding and passage of sandstone into ash, either laterally or vertically, pointing conclusively to sub-aqueous eruptions. The later flows were probably subaerial. At the close of the volcanic outbursts, after 2000-5000 feet of lavas had been erupted, the area was affected by gentle folds by which the direction of flow of the Kraai and Orange Rivers was 38 Reviews—Mesozoie Plants from Japan. determined. Then followed the gigantic and extensive intrusions of dolerite, which at the present day form such a conspicuous feature in the scenery of the Karroo, The interior of the colony was intermittently elevated, and the old land surface in the south disappeared beneath the waters of the Indian Ocean. A series of peneplains, or plains of river-erosion, mark the periods of rest and elevation of the country, the highest of which is now found at an altitude of a little over 8,000 feet above sea-level. The plateau of the Drakensberg has been deeply cut into on the west and south-west, but on the south-east it presents an almost unbroken face, over 800 miles in length, rising from 2,000 to as much as 6,000 feet above the ground at its base. TV.—Inpex Generum xr Specirrum Animattum.—Report of a Committee, consisting of Dr. Hrnry Woopwarp (Chairman), Dr. F. A. Barner (Secretary), Lord Watstnenam, Dr. P. L. Sctater, Rev. T. R. R. Sresnine, Dr. W. E. Hovtx, and the Hon. Waurer Roruscontxp. ATISFACTORY progress has been made by Mr. David Sherborn in the recording of literature from 1801 onwards. Among other works now indexed up to 1850 may be mentioned the “ Annals and Magazine of Natural History,” the ‘‘ Academia Caesarea,” and the “Neues Jahrbuch fiir Mineralogie.” Various tracts dealing with the collation of difficult books have been issued, and a reprint of the descriptions of new species of birds drawn up by Pallas for “ Vroeg’s Catalogue,” 1764, has been published by the Smithsonian Institution, under Mr. Sherborn’s care, from the unique copy in the Linnean Society’s Library. The search for rare books still continues, and any such acquisitions are made available for public use by transference to one or other of the accessible libraries. Special thanks are due to the Italian Government, the University of Padua, and Professor Dante Pantanelli for enabling the Committee to examine the “ Tavola alfabetica delle conchiglie adriatiche’ of Stefano Andrea Renier (1804). Help of this nature, as well as valuable criticism, is continually forthcoming from home and abroad, and the general interest taken in the published volume (1758-1800) is highly gratifying to Mr. Sherborn and satisfactory to this Committee, which, in this connection, desires to return its thanks especially to Mr. L. B. Prout and Mr. C. W. Richmond. EER SER Vie SE WViISE I.—Mesozorc Puants rrom Nacato anp Brronv. By M. Yoxro- yama, (Journ. Coll. Sci. Univ. Tokyo, vol. xx, art. 5, pp. 13, and 3 pls. 1908.) PROFESSOR YOKOYAMA has continued his studies of the Mesozoic floras of Japan, and in the present communication confirms his previous conclusion as to the Rheetic age of the fossil plants of the Coal-bearing series of Nagato. Hight species are Reviews—Batrachian Footprints, EH. Canada. 39 described, including such well-known Rheetic fossils as Cladophlebis nebbensis (Brongt.) and Polozamites lanceolatus (L. & H.). Several other specimens, mostly fragmentary, are figured from the province of Bitchu and are probably of similar age. A number of excellent figures of most of the species described are given. H. A. N. A. IIl.—New Species anp a New Genus or BarracniaNn Footprints OF THE CaARBONIFEROUS System In Hasrern Canapa. By G. F. Mattuew, D.S8c., LL.D. Trans. Roy. Soc. Canada, ser. 11, vol. x, sec. 4, pp. 77-110, with 5 plates, 1904-1905. HIS article contains descriptions of species that more fully present the characters of the genera described from the type Species in an article published last year in the Canadian Record of Science, Montreal. It also contains descriptions of the.new genus Dromillopus, founded on the footprints of a small Batrachian of the Coal-measures of Joggins, Nova Scotia. This article also refers the species Dromopus celer of the preceding article provisionally to Woodworth’s genus Batrachichnus. The full descriptions of the genera and species described in the article in the Canadian Record of Science are here re-presented, with additional notes. Six plates of figures accompany this article and show clearly the generic and specific characters of the species of footprints described. In conclusion, the writer makes comparisons of these footmarks with those of the frog and the alligator, and finds that they show closer resemblances to those of the latter than to the footsteps of the former, but he concludes that there are peculiarities of form in the fossil footprints not to be found in either of the recent forms used for comparison, and that Labyrinthodonts and Microsauria are responsible for many of these tracks. TI].—Rocxs or Caps Cotvitte Prentnsuta, New Zeauanp. By Professor Sottas, F.R.S. With an Introduction and Descriptive Notes by AtexanperR McKay, F.G.S., Government Geologist, New Zealand. Vol. I. pp. 289. (Wellington, 1905.) HIS volume on the rocks of Cape Colville Peninsula is chiefly devoted to the description by Professor Sollas of the specimens which were submitted to him by the New Zealand Government. Some diversity had arisen in the nomenclature of the igneous rocks which are the source of the gold in the Thames Goldfield, and it was decided to obtain an authoritative opinion by submitting a selection of the rocks to a competent petrologist. The principal object of the report is therefore to place on a satisfactory footing the nomenclature of the rocks of the Peninsula. The present volume contains only the descriptive notes on the first 204 specimens sent to Professor Sollas. That he is not responsible for the form in which they are published is evident from a somewhat pathetic footnote on p. 126, in which he disclaims responsibility for 40 Reviews—Geology in Federated Malay States. their literary style. As almost all the rocks belong either to the Andesite or Rhyolite group, the detailed petrographical notes given of each individual specimen certainly prove somewhat monotonous reading. Professor Sollas himself states that the substance of the report may be regarded as mere statement of matter of fact: we have hopes, however, that these ‘dry bones’ may yet live, since he holds out the expectation of a more comparative study for the final report, in which also the question of the origin and structure of spherulites will be considered. In a general note preceding the systematic descriptions of the specimens we have a foretaste of this final report in some in- teresting remarks on the nature of the ‘pilotaxitic’ matrix of the andesites, and also on the supposed re-fusion of rhyolites, for which Professor Sollas finds no evidence, since the so-called felspar-‘ glass’ is really only a decomposition product. To supplement the descriptions of the specimens an introductory and explanatory account of the geological position of the rocks is given by Mr. McKay. Perhaps the most remarkable feature of the volume is the wealth of illustrations; plates of photographs of scenery and of micro- photographs of the thin slices of the rocks are almost interleaved with the letterpress. IV.—GroLocy In THE FepERATED Matay STATES. Y the kindness of a friend we have seen several Reports issued by this Government, but as copies have not been sent to the Library of the British Museum (Nat. Hist.) we are unable to give a comprehensive notice of the whole of the work done. Those Reports before us are No. 8, dealing with the Geology of the Residency of Sarawak, and of the Sadong District, Borneo,’ and the Geologist’s Report for 1904.2, Mr. J. B. Scrivenor, the geologist to the Federated Malay States, after acknowledging help obtained from the staff of the British Museum (Nat. Hist.) in the naming of fossils found, reports on his journey through the areas of the four Federated States. He describes the serpentine areas of Kuala Pilah and Negri Sembilan, some of which is used for road-metal and some for ornaments. He failed to find a trace of platinum, the object of his search. Ornamental building-stone seems to be abundant, and the granites would work up on a large scale. The occurrence of tin is next dealt with and occupies the bulk of the Report. The main object of the visit to Sarawak and Borneo was economic (gold and coal). Mr. Scrivenor gives a brief but careful sketch of previous work, and proceeds to make supplementary notes. The coal-seam at Sadong is 2’ 9” in thickness, but varies considerably. It is a black bituminous coal, light in weight and easily fractured, and contains a considerable amount of calcite and some pyrites locally. It burns well and leaves little ash, but owing to its friable nature 1 Geol. Dept. F.M.S. (Kuala Lumpur), 1905, 12 pp. * Thid., 7 pp. Reports and Proceedings—Geological Society of London. 41 the furnace bars have to be especially arranged. Gold is worked down to 93 and 120 feet, and details are given of the various deposits now opened. As for the geology of Sarawak, the author refers to the papers of R. B. Newton in the Gzonocrcan Maeazine, while for the whole island the works of Molengraaff and Verbeek are the standard books of reference. The Tertiary and Secondary rocks are now well made out, but as yet fossils from the Primary rocks do not seem to have been found. Mr. Scrivenor was appointed for three years, but we hope his time will be considerably extended in order that he may have an opportunity of finishing what promises from these two reports to be a valuable piece of surveying. REPORTS AND PROCHEDINGS.- GeroLocicaL Society oF Lonpon. T.—November 22nd, 1905.—J. H. Marr, Sc.D., F.R.S., President, in the Chair. A Special General Meeting was held before the Ordinary General Meeting at which Horace Woollaston Monckton, Treas. L.8., was elected Treasurer, and Richard Hill Tiddeman, M.A., was elected a Member of Council. The following communications were read :— 1. “On a New Specimen of the Chimeroid Fish, Myriacanthus paradoxus, Ag., from the Lower Lias of Lyme Regis (Dorset).” By Arthur Smith Woodward, LL.D., F.R.S., F.L.S., F.G.S. The author, having proved that the dorsal fin-spine of the so-called Ischyodus orthorhinus is identical with an ichthyodorulite which has been named Myriacanthus granulatus, inferred that the larger ichthyodorulite U. paradoxus belonged to the same fish as the larger dentition named Prognathodus Guentheri by Egerton. This question has been settled by the discovery by Mr. 8. Curtis, in the Lower Lias of Black Ven, of a dorsal fin-spine in direct connection with a mass of decayed cartilage, dermal plates, and teeth. On the specimen the following parts are recognised :—the left and left palatine dental plates, right mandibular dental plate, cartilage of the pectoral arch, presymphysial tooth, rostal cartilage, frontal spine or tentaculum, and vomerine dental plate, dermal plates, and the dorsal fin-spine. The new fossil warrants the conclusion that Myriacanthus is a Chimeroid, closely similar to the Upper Jurassic Chimeropsis, with (i) a median chisel-shaped tooth in front of the lower jaw, (ii) a few tuberculated dermal plates on the head, and (iii) a tuberculated dorsal fin-spine. In these respects it differs from all other known Chimeroids—even from the comparatively primitive types which have been discovered during recent years in the Japanese seas. The Myriacanthide, in fact, have still no nearer ally than Callorhynchus, with which Egerton originally compared his so-called Ischyodus orthorhinus. 42 Reports and Proceedings—Geological Society of London. 2. “The Rocks of the Cataracts of the River Madeira and the adjoining portions of the Beni and Mamoré.” By John William Evans, D.Sc., LL.D., F.G.S. The crystalline rocks of the cataracts of the River Madeira and the lower waters of its tributaries are part of a ridge with a north- westerly and south-easterly strike, similar to that of the Andes, in the same latitudes. The strike is especially prevalent in Equatorial regions. With the exception of comparatively recent alluvial deposits and a few pebbles of chert, pronounced by Dr. G. J. Hinde to be of marine origin but uncertain date, only crystalline rocks are met with in the falls. They all appear to be igneous, and are mostly massive in character, though some dyke-rocks occur. In places they are typical gneisses, and they are often banded, but in some cases they show no sign of foliation. The prevailing type is acid, with a considerable proportion of alkalies, especially soda; but some of the rocks are distinctly basic in character. Analyses of several of these rocks, made by Mr. G. 8. Blake, are tabulated ; and in one case the chemical analysis is compared with one made from the proportion of minerals washed out from the thin sections. Accounts of the megascopic and microscopic characters of all the rocks encountered. are given. The more acid rocks are usually fine in grain, and are often granulitic in structure. In most cases the quartz seems to have crystallized out before the felspar. The occurrence of andalusite of chiastolitic type and of siliimanite as inclusions in a felspar is referred to, as well as the presence in one rock of an unusual type of allanite. An altered basalt is described, which contains minute concentric structures allied to those of a pyromeride. Above and below the regions of the cataracts is a wide expanse of country covered with alluvium, either of recent or later Tertiary date. 3. “The Doncaster Earthquake of April 25rd, 1905.” By Charles Davison, Se.D., F.G.S. The Doncaster earthquake of 1905 was a twin, with its principal epicentre half a mile north of Bawtry, and the other about four miles east of Crowle and close to the centre of the disturbed area of the Hessle earthquake of April 13th, 1902. The distance between the two epicentres is about 17 miles. The disturbed area contains about 17,000 square miles, including the whole of the counties of Lincoln, Nottingham, Derby, Stafford, Leicester, and Rutland, the greater part of Yorkshire, and portions of Lancashire, Cheshire, Shropshire, Worcestershire, Warwickshire, Northamptonshire, Cambridgeshire, and Norfolk. The originating fault runs from about 1. 38° N. to W. 38° S., and appears to be nearly vertical within the south-western focus and inclined to the south-east in the north- eastern focus. The first and stronger movement took place within the south-western focus. A twin earthquake is probably due to the differential growth of a crust-fold along a fault which intersects it transversely, the first movement as a rule being one of rotation of the middle limb, accompanied by an almost simultaneous slip of the two arches, and followed soon afterwards by a shift of the Reports and Proceedings—Greological Society of London, 43 middle limb. The movements in which the Doncaster earthquake originated presented a slight variation in this order. They consisted of successive but continuous displacements, first of the south-western arch, then of the middle limb, and finally of the north-eastern arch. II.—December 6th, 1905.—J. E. Marr, Sc.D., F.R.S., President, in the Chair. The following communications were read :— 1. “The Physical History of the Great Pleistocene Lake of Portugal.” By Professor Edward Hull, LL.D., F.R.S., F.G.8. The formations bordering the lower banks of the Tagus near Lisbon are arranged by the author in the following order of succession :— 6. Recent and QuaTEeRNARY. Alluvia of the Tagus. 5) Se { ee with ZLymnea (Lacustre superior). ands and grayel. 4, Post-PLiocenr and j Not represented, unless by some land- PLIOCENE. — (glacial beds due to elevation. 3. Miocene. ‘Almada Beds.’ Calcareous marls and lime- stones, with marine fossils. 2. Eocene (?). Unfossiliferous sands and gravels (Lacustre inferior). 1. Upprr CRETACEOUS. Hippurite Limestone. A description is given of the Lacustre superior; the Almada Beds are considered to be Miocene, and as the Pliocene is not represented, except possibly by certain glacial deposits, the author considers that that period was one of great uplift, when the suboceanic gorge, an extension of the present course of the River ‘Tagus, was excavated. ‘The margin of the lake was probably formed by the granite of Das Vargans and Cunheira. ‘There is evidence that the general level of the lake-bed was nearly that of the outer sea, and that the sea-waters gained occasional access to the lake during the earlier stage of its formation. The lake was eventually drained by the channel cut by the Tagus at the harbour of Lisbon, upon the elevation of the land to about its present level. 2. “The Geological Structure of the Sgurr of Higg.” By Alfred Harker, M.A., F.R.S., F.G.S. The pitchstone which forms the Sgurr of Higg is a massive sheet, some 400 feet thick, reposing with discordance upon the succession of alternating basalts and dolerites which make up the greater part of the island. The lower surface of the pitchstone is irregularly undulating, and in two places fragmental accumulations are seen immediately beneath it. The generally received interpretation regards the pitchstone as a lava-flow, or series of flows, occupying _an old river-valley excavated in the basalts, and the fragmental deposits have been regarded as river-gravels of the pitchstone age. This is the view put forward by Sir Archibald Geikie. After a detailed survey of the ground, the author finds it impossible to accept this view, and he gives reasons for considering the pitchstone to be intrusive. The form of its base, as mapped out, does not seem to be reconcilable with that of a river-valley, A Reports and Proceedings—Mineralogical Society. and its character is that of an intrusive junction rather than an erosion surface. The fragmental deposits are believed to be of voleanic origin and of the basalt age. The one exposed at the seaward termination of the ridge is a volcanic agglomerate, probably filling a small vent. The other, seen at the southerly base of the Sgurr, is a bedded agglomerate, partly rearranged by water action. The Torridonian and Oolitic sandstone blocks which are abundant in it are held to have been brought up from below, and fossil wood of Oolitic age has been brought up in the same manner. The absence of fragments of the sill-dolerites (themselves younger than the lavas, but cut off by the pitchstone) in both accumulations seems to assign them unequivocally to the age of the basalt, and their conjunction with the pitchstone must then be considered accidental. The conclusions arrived at bring the rock of the Sgurr of Higg into relation with the other British Tertiary pitchstones, which are all intrusive. Thus also is avoided the difficulty of assuming a great erosion in inter-volcanic times, a hypothesis for which the supposed river-valley was the sole evidence. Dr. J. W. Evans, in showing a new method of determining the, optic axial angle of a biaxial mineral, by rotating it in parallel polarized light, on an axis at right angles to the optic axial plane and to the axis of the microscope, said that the position in which the relative retardation was zero corresponded to the optic axes, and the angle between these positions was the optic axial angle in air or in the medium in which the mineral was immersed. To determine when the relative retardation is nil the nicols are placed at angles of 45° with the axis of rotation; the double wedge described in the Mineralogical Magazine for May last (vol. xiv, p. 29) is then inserted, and the position noted when the bands on the two halves of the wedge are in exact continuation of one another. This method is applicable to sections of minerals in rock-slides which are cut at right angles to the optic axial plane; for the observation can be made with a low power, which admits of the slide being freely rotated in a stage goniometer. With the higher powers which are necessary for microscopic observations in convergent light, a rock-slide could only be rotated within very narrow limits. Dr. F. A. Bather exhibited fossils from various localities in New Zealand, hitherto known as “the Mount Torlesse Annelid,” described in the Grotocican Magazine (December, 1905, p. 532). Adds further information thereon ; for which see his letter, p. 46 below. TiT.—Mineratocicat Society oF Lonpon. November 14th, 1905; Professor H. A. Miers, F.R.S., President, in the chair.—The Determination of the Angle between the Optic Axes of a Crystal in Parallel Polarised Light, by Dr. J. W. Evans. The crystal plate is rotated on the optic normal as axis, and the positions are determined in which the relative Reports and Proceedings—Mineralogical Society. 45, retardation is nil. This may be observed by using a gypsum plate or the double quartz wedge devised by the author. In the latter case the positions in question are marked by the coincidence of the bands in the two halves of the wedge. ‘This gives a very exact reading if strictly parallel light be employed.—Mineralogical Notes (Diopside and Albite), by Professor W. J. Lewis. A large tabular crystal of white diopside, a brown diopside of unusual habit, and a Carlsbad twin of albite were described.—Note on the Crystallisa- tion of Drops, especially of Potash-alum, by Mr. J. Chevalier. The President described observations made by Mr. Chevalier on the crystallisation of drops of solution of potash-alum. These generally yield in succession (a) birefringent spherulites, (6) octahedra, and (c) a fine rectangular network. (a) is probably a less hydrated alum, and it becomes isotropic on exposure to moist air by conversion into (b). (c) is ordinary alum which is in a state of strain, owing to its rapid crystallisation, and becomes white and opaque after a time owing to the development of cracks. Drops. observed upon a slide under the microscope behave differently according as they are in the metastable or labile condition. A meta- stable drop inoculated with (a) or (b) or (ec) deposits octahedra. A labile drop inoculated with (a) deposits spherulites, but inoculated with (6) or (c) deposits the rectangular network. Whena metastable drop containing either octahedra or spherulites, or both, passes into the labile condition (by cooling or by evaporation) they may continue to grow unchanged. If, however, a fragment or germ of octahedral alum be introduced into a labile drop, the network (c) is immediately produced. An alum crystal growing in a labile solution is surrounded by a zone of metastable liquid which prevents it from starting the network (c) characteristic of a labile drop. Experiments were made upon the action of various mineral substances in inducing crystallisation in metastable and labile drops. Among these the holosymmetric cubic crystals, and especially galena, exercise a remarkable effect in producing the network (ce) in labile drops.— Note on the Formation of Gypsum Crystals in a disused Well at Chemical Works, by C. J. Woodward. Groups of gypsum crystals were exhibited which were found thirty years ago studding the walls of an old well at Messrs. Chance’s Chemical Works at Oldbury.— Notes on Minerals recently found in the Binnenthal, by Mr. R. H. Solly. The minerals described were: (1) Ilmenite, in brilliant crystals, displaying marked hemihedrism and showing five new forms. It is associated with quartz, adularia, magnetite, and mica, on mica-schist. (2) Seligmannite; an exceptionally large and well- developed crystal in dolomite. Unlike any previously described, it is untwinned; altogether 45 forms were observed, of which 21 are new. (8) Marrite; two more crystals of this rare mineral were found, one tabular and the other sharply pointed in habit. (4) Proustite; a minute crystal deposited on a crystal of rathite. (5) Trechmannite; a crystal of this rare mineral displaying asymmetric hemihedrism, deposited on a crystal of binnite. (6) Hyalophane, in crystals of an unusual green colour. 46 Correspondence— Dr. F. A. Bather. CO. FeseiS 2 @sy Das Gor. THE AGE OF ‘THE MOUNT TORLESSE ANNELID.’ S1r,—In my paper on these fossils (Grou. Mac., Dec. V, Vol. II, pp. 532-541; December, 1905) it was said that the beds containing them were “usually regarded as the uppermost division of the Maitai Series”; but the stratigraphical position of that series was treated as an open question, though “ probably not below Upper Carboniferous and not above Trias.” The paper was unfortunately written without reference to a valuable series of articles by Professor James Park, of Otago University, contained in the Transactions of the New Zealand Institute, vol. xxxvi. From these papers it appears that “a good deal of doubt must attach to the determinations” of the fossils found by Mr. M’Kay in the Maitai Limestone; the fossils collected by Professor Park in the same bed are identified by him as “Spiriferina (two sp.), , 2. Aperture of Reptelea pyriformis (Michelin). After Michelin. ,, 3. Aperture of Reptelea acteon (VW Orbigny). After d’Orbigny. 4, Aperture of Semimultelea Divoni, n.sp. From the type-specimen (B.M. D 7845). : Aperture of Reptoceritites Rowei, Gregory. From the type-specimen (B.M. 1D 4244), 6. Aperture of Semimultelea irregularis, VOrbigny. From the specimen B.M. D 4867. »? o 99 1 T.e. local recapitulations. See R. T. Jackson, ‘‘Localised Stages in Develop- ment’’: Mem. Boston Soc. Nat. Hist., vol. v, No. 4 (1899), pp. 92,189, 141. See also W. D. Lang, ‘‘ Stomatopora antiqua, Haime”’: Grou. Mac., 1908, pp. 259, 260. F. J. Bennett—Machine-made Implements. 69 Fic. 7. Aperture of Semimultelea acupunctata (Novak). After Novak. pp fo ID vans), » 9. Aperture of Reptomultelea sarissata, Gregory. From the type-specimen (B.M. D 7106). », 10. Aperture of Reptomultelea Reussi (Pergens). After Pergens. Other zoccia _ in Pergens’ figure have a much more rounded distal angle. », ll. Aperture of Reptomultelea tuberosa, WOrbigny. From the specimen B.M. 36,746. 5, 12. Part of the zoarium of the type-specimen of Semimultelea Dixoni, n.sp. (B.M. D 7845), showing normal zocecia (7.2.) ; closed zocecia (¢.z.) ; a topomorph with ridges between the zocecia (¢.r.); and a topomorph composed of areas marked out on the zoarium by raised ridges, but with no closed or open apertures (¢.). x about 24. Somewhat diagrammatic. V.—MacHiIne-MADE IMPLEMENTS. By F. J. Bennett, F.G.S. Lon has lately been called by M. Marcellin Boule to the production in cement-mills in the Commune of Guerville, near Mantes, of all the more characteristic forms of Holiths, and of these he has given photographic reproductions. The evidence for the necessarily artificial shaping of Holiths had for many years been questioned by him, because he had found chipped flints of this character in the midst of Oligocene or Miocene beds in Auvergne and in the Velay; and it seemed imprudent to infer the existence -of man in those early stages of the Tertiary period in the absence of osteological evidence. In speaking here of machine-made implements I do so advisedly, because all stone implements were once referred to natural or ‘supernatural causes; the obvious arrow-head, for instance, being termed an ‘elf-bolt.’ M. Boule, however, seeks only to show that stones shaped like Holiths may be produced by Nature, because he finds that they are produced by certain pseudo-natural, machine-made torrents, and so considers that Holiths are due to such torrential action. Yet the Holithic deposits known to the writer do not seem to indicate torrential action. The first objection is that M. Boule compares known and unnatural agencies with natural ones, and the analogue of his machine-made torrent would be hard to find in Nature and would be most exceptional there, and yet to this he would refer all Holiths.' The Mantes wash-mill apparently deals only with flints fresh from the chalk, while the flints from which the Kent plateau Holiths were made were mostly tough and much weathered, and not as a rule ‘such flints from which good chipping can be obtained; and that may account a good deal for their rough execution, and for their non-acceptance by some observers. Anyone who is a flint-knapper knows that the results obtained from the one kind of flint are very different from those obtained from the other, that the fracture varies with the flint, and that in 1 Nature, Aug. 31, 1905, p. 488; Sept. 28, p. 538; and Oct. 26, p. 685; see also L’ Anthropologie, vol. xvi, p. 257, in which the detailed observations of M. Boule are published. 70 F. J. Bennett—Machine-made Implements. some flints the human fracture is not distinguishable from the natural fracture. The mill also rotates at a definite speed for a definite time, and so cannot compare with Nature. In order to get any results of value, the flints should be examined first, and samples taken out from time to time and compared, and yet the flints in question are only taken out after about 29 hours’ interval. There is another complication, which also seems to introduce a human element, if we may say so, in the case of the harrows with chain attachments, and these harrows in one of the mills visited by the writer were also weighted with old gear wheels, etc. So that, added to the impact of flint against flint, there is also a possible knapping action due to the teeth of the harrows and to the links of the chains, and these, in shape and possibly in effect, would compare with the pebbles used in knapping; the teeth, too, of the old gear wheels may also be chipping agents. Hence it becomes more difficult to say by which of these agencies, or by their combination, the fractures are produced. Thus any quasi-human results may be due to these quasi-human agencies introduced. It is also possible, if the area contains worked flints, that these may be introduced. And in the cases we have investigated such flints do occur in the area. The analogy also with Nature would be closer if the harrows, etc., could be removed and the flints subjected only to the torrential action of the water. So much for some of the objections. I will now give some account of the observations I have just made at certain wash-mills in Kent. These mills are confined to brickyards. The results are found to vary with the kind of flint, with that of the matrix, and with the proportion of this to the flints and to their size. I will take the mills as I observed them, but the washing process was not then in operation in any one of them. The first was that at Pascall’s Kiln, at Platt, near Wrotham, Kent. There, resting irregularly on the Gault, is an angular white flint gravel much weathered, together with some much worn flints. At another part of the brickyard is a sandy loam with some blocks of sandstone and a few small scattered flints, and this seemed to be washed together with the Gault, as the wash-heap also contained sand and rounded lumps of sandstone. The small angular flints were not affected at all by the milling action, and the other flints only slightly so. Samples of all those that were at all like implements were taken, and most of those were Kolithic in form merely, and photographs of these would pass as good EKoliths, but some of rude palzolithic form were also found. The flint being of a coarse and cherty nature, the ‘ work’ was rough in accordance with this material. On two of the specimens the writer, who can knap so that he can deceive an expert, and can treat the chipped flint so as to remove the new look, tried his hand, and chipped and bruised and ‘treated’ (the work of a few minutes only) one side of each specimen, so successfully that there was no real difference between his side and F. J. Bennett—Machine-made Implements.. - 71 the milled side. So that one side was possibly mill-made and the other certainly hand-made. This would seem to leave the case of the mill, in this instance, as non-proven, or rather in favour of man. The other place visited was Temple Farm Brickyard, near Strood, Rochester. Here there are two wash-mills, a lower and an upper one, each with its refuse heap. Here the conditions in the one differed from those in the other, and so did the ‘ work’ on the flints. At the lower brickyard is a long extended section of brickearth across the wide trumpet-mouthed opening of the valley. This shows 20 feet of clean sandy loam, laminated in places, and with occasional small seams of pellety chalk and very small angular flints and small pebbles. This loam is thinly capped by stony loam with some scattered flints, some angular and others more or less worn. The lower refuse heap was composed mostly of a mixture of fine flinty gravel with many small pebbles, and much pellety chalk and many lumps of ‘ginger,’ and very few large flints. Some of these, which were like those fresh from the chalk, were very little rolled or chipped, and the reason was plain, as they were contained in a matrix that kept them from contact with each other, and so their original condition was little affected. The upper mill is higher up the valley; there the brickearth was dug in two places, one in a terrace on the valley side and the other in the bottom of the valiey. That in the terrace showed six feet of stony loam resting on a marly, pellety chalk, with many large and mostly angular flints, little worn and like those fresh from the chalk; the other flints were much worn and weathered, with a few pebbles. The second section had fewer flints and was mostly in the pellety chalk. Thus this brickearth seems due to the decalcification of the chaiky waste formed during the denudation of the stiffer and more stony loam in the upper, and the finer washed loam in the lower part of that valley. One great refuse heap at the upper mill was mostly composed of large flints, some of Holithic form, but evidently shaped, as the old patina showed, before they entered the mill, while one or two were of paleeolithic form and one neolithic. Here the chipping, rolling, and bruising due to the mill apparently, though slight, was much more noticeable than at the lower mill, as here there were so many more and larger flints to act on each other and to be acted on by the harrows, etc. A very good imitation of beach action was seen in the many rounded lumps of chalk, etc., from the loam in the large refuse heap. All that the mill then seemed to have done was to round and bruise and re-chip in an irregular manner the sharper original edges, as offering the least resistance. Where old indentations occurred, it would seem that the teeth of the harrows had found these out, as they were re-touched in some cases and the old patina removed in places. Thus it would appear that the mill, like the sea, in the writer’s opinion, rounds rather than shapes, and so deforms any flints that had been previously chipped into a definite shape. Though he has not visited any chalk wash-mills, the writer has seen some flints from one near Sevenoaks, and these were thin 72 Rk. WM. Brydone—Further Notes on the Trimmingham Chatk. pieces of flint irregularly chipped at the edges, but not apparently ‘formed’ in any definite way. In chalk wash-mills, as in the examples mentioned, much must depend on the proportion of the flints to the mass of the chalk and on their size, as the more numerous and the larger the flints, the more will they be affected, and vice verséd. Thus the power of the mill, as able to shape Eolithie flints, must, in the cases observed by me, be considered as non-proven. The difficulty of the whole question consists in this, that we are trying to decide where no final decision seems possible. For those who hold that certain flints are due to natural causes have never seen, or can see, Nature doing what they would refer to Nature, and those who uphold the human origin of the flints could never, of course, have seen them actually made by man. But we have actual proof that man has and does fashion certain stone tools, and therefore have good reason for asserting that man did make some of these early tools, and we also know that man improves on his early work, so that the best forms of these cannot be man’s earliest efforts. The difficulty always will lie in fixing the starting- point of his ’prentice hand. The stages in the progression from the ruder to the more perfect forms were probably these. As soon as man found that some adjunct to the hand was needed in his conflict with Nature and the beasts, sticks, bones, shells, and stones were used. Of these, only stones, for the most part, have remained. The stones, in the first instance, would be those best adapted to his needs, and were so selected. Next it might occur to him that he might imitate those natural forms: hence the difficulty to distinguish between the apparently natural forms and the possible artificial ones, both having only one sharp or sharpened edge. Then he would gradually learn so to adjust the angle of incidence as to extend the chipping all over the flint, and at last to select the kind of flint that gave the best results. The process must have been a gradual one, with intermediate stages, with reversions perhaps to older and ruder forms, and the difficulty will always lie in fixing the starting-point of the undoubted artificial stage, and I do not think that the wash-mill evidence will help to do this. But if may cause those who have been too ready to accept worked flints to be more careful in the future. Vi.—Furtrurer Notes on THE STRATIGRAPHY AND FAUNA OF THE TRIMMINGHAM CHALK. By R. M. Bryponz, F.G.S. (PLATES IV AND V.) (Continued from the January Number, p. 22.) OWNWASHED sand and mud much obscured the section, but the clay appeared to be definitely continuous, while the chalk might be continuous under the mask of mud, but did not seem likely to be so. The section suggested very strongly a flat sheet of clay GEOL. MAG. 1906. Dec. Vj. Vols wii sR ive Views of the Trimmingham Chalk Bluffs, Norfolk Coast. (To illustrate Mr. R. M. Brydone’s paper.) R. M. Brydone—Further Notes on the Trimmingham Chalk. 73 pushed at a level some way below the beach against a backward ‘sloping and then overarching surface (e.g. the side of a cave), which it had followed until doubled back upon itself. The masses of chalk in the bay, where accessible, all showed Ostrea lunata chalk, except the stringer from the bluff. This was -accessible from above, and was then composed solely of the grey chalk. It was quite clear that the landward face of the bluff was not parallel to the coastline, but ran about east and west, the bluff being ‘therefore a rude triangle with its apex, towards the north. The landward face was covered by what appeared to be crushed blisters of finely laminated clay apparently formed round projections in the surface of the chalk. In the Autumn of 1904 I sot desperate. at my inability to satisfactorily sketch the constant changes which were taking place, and borrowed a camera, and since that time I have a fairly continuous series of photographs, some of which are reproduced as Figs. 6 to 18 in the plates illustrating this article. Unfortunately I had had no previous experience of photography, and I have always chanced upon dull and cloudy weather, so that I may be forgiven for the imperfection of the photographs. As it is, they show far more than I ever dared to hope for. They are all, I think, self-explanatory except Fig. 9, which was taken from the summit of the bluff, and in which the boundaries between the grey chalk above and below and the O. lunata chalk between is traceable in the ‘slope’ (the nearer piece of chalk) by a slight variation in shade. During the period eorERenl by these photographs erosion has been very rapid at this point (the clay seen on the left hand of the bluff in Fig. 18 was faced with chalk of fair thickness six months previously) (Fig. 8), and several further points of interest have been disclosed. The most important is perhaps that.shown in Figs. 10, Ji, and 15. The cutting back of the main cliff has provided a section across what appears to be an erratic mass of rudely stratified flint shingle, varying from very coarse to fairly fine, with a bed of sand in the middle and a long thin slice of chalk at its left hand, the stratification being vertical. The slice of chalk, though nowhere more than two feet thick, contains both O. lunata chalk and grey chalk with an occasional grit seam at the base throughout the whole dJength I have been. able to examine, the O. lunata chalk being next the clay which forms as it were the backing of the mass.. The lower end of the chalk slice was recently exposed, and the clay was seen to run down beside it and then turn at right angles in under it (Fig. 15), with the banding parallel to the surface of the chalk, which seems inseparable from the junction of clay and chalk here. The whole thing very strongly suggests a piece of shingly beach set -on end, the chalk representing the basement bed on which the shingle was heaped up. ‘The rude stratification of the shingle is what might be expected from the sifting together of the pebbles of ‘similar size which takes place in every beach, the coarsest part being that next the chalk. This huge mass of shingle, which can hardly 74 R&R. MW. Brydone—Further Notes on the Trimmingham Chalk. have been transported from any distance, as it would not have held together, forms an interesting parallel to the masses of coarse._shingle which lie on the top of the northern part of the south bluff as recorded in my previous pamphlet (see also Fig. 1 hereto). Another point of interest is the behaviour of the grey bed in the seaward face of the bluff. As this was cut back the grey bed developed a deep pocket, shown just beginning in Fig. 7 and complete in Figs. 18 and 17, at the bottom of which the gritty basal seam thickened considerably and became exceptionally coarse. (It will be noticed in these figures that the two upper flint beds shown in fig. 1 of my previous pamphlet have become comparatively indistinct, while the third has become very marked. At the moment of writing the second is regaining its importance.) On the left-hand side of this pocket the base of the grey chalk rises very sharply, so that the chalk which strings out into the clay, thin as it is, becomes, as on the other side of the bluff, composed of a layer of O. lunata chalk below and a layer of grey chalk above. There is clearly at this point a very strongly marked unconformity between the two beds of chalk. Another point is that O. lunata chalk has come in between the- grey chalk and the clay in the cross section at the end of the north side of the grey chalk bay and at several other points in this mass where the grey chalk and clay were previously in contact, so that it seems fair to assume that the distance by which the grey chalk overlaps the O. lunata chalk is slight everywhere. Whenever the grey chalk has been removed from off the O. lunata chalk beneath it the latter has always presented a decidedly wave-worn and smoothed appearance. This grey chalk, as before stated, presents some remarkable peculiarities besides its basement bed of grit with flint and chalk pebbles. It is very soft, but contains a great abundance of hardish lumps of varying shades of grey which are not clearly rolled, but have very smooth and suspicious outlines. These lumps are very similar in texture, and, so far as I know, identical in fossil contents with their grey matrix. The flints present two facies. One, which is generally small, is dark grey throughout and very soft, being often little more than a central mass of spongy texture, but no definite shape, surrounded by a very thin skin, very imperfectly silicified and easily cut with a knife on slight pressure. The other type appears to be confined to the base of this chalk, and includes nearly all the large flints. It is very thoroughly silicified and black inside with little or no cortex, and light bluish grey outside. These, like the included lumps, suggest gentle rolling, but contain only the same fossils as those of the grey matrix, including the peculiarly characteristic ones, and certainly no specimen of O. lunata, which occurs in profusion in the flints of its own horizons. The bed as a whole is certainly not reconstructed, for the grey matrix abounds in fragile fossils in absolute perfection, the most striking being Ostrea inequicostata, bivalved Ostrea ungulata, and numerous branches of Vincularia and other Polyzoa. The fossils show the R. M. Brydone—Further Notes on the Trimmingham Chath. 75 unconformity between the grey chalk and O. lunata chalk as clearly as the stratigraphy. Ostrea lunata and the bun-shaped Echinoconus are unknown in the grey chalk, which is full of Ostrea inequicostata, O. canaliculata, and Terebratula obesa, none of which have ever yet been found in the O. lunata chalk. There are very similar grey beds on the foreshore underlying white chalk without O. lunata, which passes up into O. lunata chalk, but below they are cut off by a fault, and until we know either what overlies the grey chalk of the bluff or underlies the grey chalk of the foreshore it is not safe to identify the two sets of grey beds, though it is very tempting, the similarity being very striking, especially in the fossils. At the beginning of October, 1905, the clay behind the bluff was broken through by the waves, and by the middle of the month the bluff had been completely isolated and a secondary bluff formed behind it out of the seaward face of the O. lunata chalk underlying the ‘slope’ of grey chalk, which had by this time become mainly a slope of O. lunata chalk showing several lines of flint dipping gently seaward. The cross section of this secondary bluff showed gently arched lines of flint, from which it was clear that this secondary bluff was the top of a gentle anticlinal fold rising towards the land, exactly like the ridge forming the southern part of the south bluff. It was, however, underlain where its base was clear of sand by clay visibly continuous in the south bay with the clay underlying the chalk masses. The same waves that had breached the clay pinnacle had also cleaned the section in the south bay, which is recorded by Fig. 17. The clay appeared to have pressed upwards from under the mass of chalk nearer the bluff and carried up with it on its surface the mass high up in the cliff, for the two were connected by a very thin but unbroken line of chalk which kept the clay above the masses of chalk from quite touching the clay which emerged from beneath them. A similar but more partial appearance was presented in the north bay by the clay which emerged from under the ‘slope’ and passed up into the cliff, only to arch over and, as before stated, pass down beside and in under the erratic slice of chalk. Both the masses in the south bay, i.e. the lateral section of the ‘ secondary bluff’ and the mass seen high up in the cliff, were composed of O. lunata chalk with about a foot of grey chalk above separated by the regulation grit seam with pebbles, and above the grey chalk came about six inches of very regularly bedded sharp grey sand with one interlaminated seam of black clay, and above the sand about 2 feet of dark bluish grey clay. Between the two masses of chalk the sand was cut out by the clay above it, but over the masses themselves it was very regular. Above the bluff it passes into a coarse gravel. The most recent exposures of the north side of the bluff itself appear to show an actual inversion of all the chalk below the thick flint. These flint lines are not clearly marked on this side, but their appearance is quite consistent with and indeed suggestive of their being actually inverted, and the hypothesis that they are actually 76 RU Brydone—Further Notes on the Trimmingham Chath. inverted is made very probable by the fact that the seams of O. lunata up to and including that immediately below the thick flint follow the same inverted course, a fact pointed out to me by Mr. Bidder. Now it will be remembered that the O. lunata chalk was continuous across the gap, and that the gap was quite recently fairly narrow, and though no bed of flint happened to occur in the arch of O. lunata chalk crossing the gap, I am convinced (and Mr. Bidder is equally positive) that the thick flint in the bluff was identical with the flint line at a corresponding height in the ‘secondary bluff’ (Fig. 14). If we are right, then the thick flint was not involved in the inversion. That being so, we should expect to find filling the gap which would otherwise be left between the thick flint which continues more or less horizontal, and the beds below which break away from it, an area of reconstructed chalk, and this is exactly what does occur there. The sketch below will show what is meant :— Diagram-sketch of the north-west face of bluff. St, SF, f, flint bands; 0, 0, 0, seams of perfect O. Zunata in section. A, area composed of chalk crowded with comminuted 0. dwnata and no other fossils. Now I think we are entitled to assume (until the contrary is shown) that the inversion is a result of the same, or practically the same, force which has so greatly tilted the beds which are not actually involved in the inversion, for both the tilting and the inversion must have been produced before the deposition of the grey chalk on the upturned ends of the tilted strata, since neither the tilting nor the inversion has affected the grey chalk, and that fixes the tilting and the inversion as of late Cretaceous age. Hvidently all the beds now appearing in the bluff were tilted together, but by the time the angle had been reached at which the uninverted beds now stand, these beds must have been raised above the plane at which the thrust was operating, and the lower beds, being still in that plane, must have been forced to part company with the uninverted beds, no great matter, as the whole could by that time have only been lightly consolidated, and turn under themselves. This view conforms very well with Lyell’s figure of the bluff when it was about twenty times its present length. This figure shows at the north corner a small area of chalk with a steep dip which RK. M. Brydone—Further Notes on the Trimmingham Chalk. 77 flattens out southward to quite a gentle dip over a comparatively very extensive area, showing the steep dip to be very local. Probably we have in the bluff of to-day a remnant of the steeply dipping area only of Lyell’s bluff, but whether that is so or not Lyell’s figure is a very strong argument against assuming the general prevalence of a steep dip at this point. The only possible explanation of these local phenomena seems to be one on the lines of the original and ingenious theory of Mr. Clement Reid, varied by postulating the lateral thrust as of Cretaceous age, directed almost due south and very local, and leaving the thrusting agent altogether indefinite. Hxcept at this very point the thrusting force only created a gentle anticline. This anticline of greatly varying sharpness must have been exposed to denudation, which planed off the upper part and more or less flattened the sides, and the surface so formed was then resubmerged and the grey chalk deposited on it to a minimum thickness of three feet. At some date shortly before the formation of the glacial beds, the chalk must have been again raised and exposed to a south-westerly sea, which formed caves in it which were filled by the first inflow of boulder-clay. The bottoms of these caves are probably well below the present beach level, and we only see horizontal sections through the roofs and the upper surface of the infilling clay, which of course then appears to be underlying the thin edge of the broken-through roof by natural deposition. ‘he detached masses of chalk seen in the cliff behind the bluff have clearly been carried up by a mass of clay from below, and represent parts of the roofs of these caves, which were too weak to resist the upward pressure of the clay. Possibly this upward pressure was applied at a much later date than the infilling of the caves, for the thin line of chalk recorded as connecting two masses of chalk is strongly suggestive of chalk, so to speak, rolled out between the upper and lower clay, and this could only take place by a fresh movement of the lower clay after the upper clay had taken up its present position. It is also suggested by the regular blending of the deposits immediately overlying the chalk just at this point that after the first influx of clay had filled up the sea bed to the level of about the top.of the chalk there was an interval, during which the above-mentioned regular deposits were formed on the new sea floor so created, before this sea floor was covered by the upper clay, and then broken up by renewed motion in the lower clay. 5. Other Hxposures. A new feature of interest is the exposure for a short time of a patch of O. lunata chalk, about 80 yards by 12, some 340 yards to the south of the south bluff, i.e. roughly, intermediate between it and the short ridge exposed some years ago at the foot of the cliff under the brickfield (which latter I will call for convenience the brickfield chalk). This new patch of chalk was practically touching the base of a great mass of firm clay which forms at present the first headland to the south of the south bluff, and appeared to pass 78 Rk. M. Brydone—Further Notes on the Trimmingham Chatk. under this clay in the cliff and also under clay to the northward, its other boundaries being formed by sand. It appeared to represent the top (or rather a section across the upper part) of a flat ridge running and sinking in the usual direction about 30° south of east. Its southern and eastern ends were capped by a practically continuous sheet of flint, identical in appearance with a sheet of flint which I had previously observed on the foreshore close by coating one side of a ridge of O. lunata chalk heading in this very direction. The brickfield chalk recorded in my previous pamphlet I have never seen again, but once or twice in 1900-1904 there just showed through the sand some way further down the beach a narrow ridge of O. lunata chalk once visible for as much as 30 yards, and apparently running out to sea in much the usual direction, and in a line with the first recorded brickfield chalk. This ridge has been frequently just visible during 1905, and in October, 1905, it was gradually exposed to a length of over 66 yards. It was nowhere more than 4 feet and rarely more than 2 feet thick, and dipped very steeply to the north. It seemed very remarkable that such a long thin ridge should have been preserved on a foreshore, though there were strong indications that it increased greatly in width at a very short distance deeper down. But a still more remarkable thing was revealed on close examination, i.e. that throughout practically its whole length it was composed of a layer of O. lunata below and a layer of grey to white chalk above, separated by a grit bed full of rolled flints and chalk, and agreeing most exactly, except for its ereater thickness (maximum at least 6 inches) and the greater size of the flint pebbles, with the grit bed at the base of the grey chalk in the north bluff over a mile away. I have little hesitation in identifying the two grit beds, for though the brickfield chalk above the grit bed was not uniformly grey, it contained many hardened and apparently rolled lumps of chalk. I could not find there any of the characteristic grey chalk fossils, but the total amount of chalk exposed was very small, and the physical identity is very pronounced. EXPLANATION OF PLATES. Views of Trimmingham Chalk Bluffs, Norfolk Coast. Various views of the North Bluff and the exposures in the bays on either side of it. Pruate lV. Fic. 7.—Photograph taken November, 1904. 8.—South bay ; November, 1904. 9.—Head of north bay from top of bluff; May, 1905. Prats Y. Fic. 10.—North bay, showing slab of chalk on end in cliff; April, 1905. 11.—Showing slab of chalk and mass of stratified shingle on end; May, 1905. 12.—North Bluff, seaward aspect; May, 1905. be) (Lo be concluded in our next number.) GEOL. MAG. 1906. Dee. V, Vol. IIT, Pl. ¥. Views of the Trimmingham Chalk Bluffs, Norfolk Coast, (To illustrate Mr, R. M. Brydone’s paper. ) my 5 ss : 7 i ae > = a a Oe < S, “ 7 7 &, 7 iPg a foo a ‘ J ‘ s “oi idl ba ’ , 4 Hy FT . Tu Ty a ish oe cle «lah jag att ihe a a , + Pl *, “a je Aa? ace. yw T. Mellard Reade—Radium and Earth-shrinkage. 19 VII.—Rapium anp THE RADIAL SHRINKAGE OF THE HARTH. By T. Metiarp Reapz, F.G.S., F.R.I.B.A., A.M.1.C.E. N his Presidential Address to the British Association, South African Meeting, 1905, Professor G. H. Darwin points out that the presence of radio-active materials in small proportion in the sun would serve to explain the present radiation, and “that con- centration of matter is not the only source from which the sun may draw its heat.” Professor Darwin goes on to explain how this enables us to extend the possibilities of geological time beyond that to which some physicists would limit us. My object in writing this is to point out that if the sun’s heat is kept up by the presence of radio-active materials the same must follow with regard to the earth. The rate of cooling of the earth must consequently be slower in proportion to the quantity of heat generated by the radio-active matter present in its substance. It further follows from these premises that if the generation of , heat by these radio-active matters in the earth equals the dissipation of it at the earth’s surface the globe will be kept at the same average temperature. If this be the condition of the earth at the present time there can be no radial contraction taking place unless due to some other cause than loss of heat, and the same may be predicated of any previous period. This is no doubt stating an extreme case, but if, on the other hand, we assume that only a portion of the heat lost by the earth by conduction and radiation is replaced by that generated by radio- active bodies, by so much will the radial shrinkage be reduced and the mountain- making activities on the contraction hypothesis rendered less efficient. It has been shown by Osmond Fisher and myself that the gradual dissipation of the initial heat of the earth, considered simply as a cooling body, that has taken place in the past is quite insufficient to provide the radial contraction demanded by the contraction hypothesis.‘ If any of this lost heat is renewed this inefficiency is proportionately intensified. Our ideas of the constitution of matter are undergoing serious changes, and it becomes increasingly important that geologists should keep themselves abreast of the times. The bugbear of a narrow physical limit to geological time being got rid of, we are free to move in our own field of science. The methods of geology have this advantage over those of pure physics, we can more readily appeal to nature for confirmation or disproof. . May I be permitted to point out that while the discovery of radium has shaken the foundations of what may be designated the mathematical theory of the earth, it strongly supports those who like myself have long contended that the forces which create mountain ranges, raise continents, and give external form to the 1 Fisher: ‘‘ Physics of the Earth’s Crust.’’ Reade: ‘‘ Origin of Mountain Ranges”’ ; “ Rvolution of Earth Structure.’’ 80 Notices of Memoirs Segregation of Sulphide Ores. earth reside in the earth itself, and that ‘the earth is not merely an inert mass cooling in space.” ! Our conception of the geologic potentialities of matter has beem marvellously widened by the recent discoveries. How these dis- coveries may affect our views of the interaction of matters as explaining geological changes remains to be decided when the new methods are established on a firm basis, of which there seems to be an early prospect. NWOTLCEHS Oc / AEROS, ee a _l Abstracts of Papers read before Section C (Geology), British Association : South Africa, 1905. I.—On tHe Marcrnan Puenomena or Granite Domss. By Professor GrenvittE A. J. Coun. N examining the gneisses of the counties of Donegal and Tyrone, which have been in part regarded as sheared Archean masses, the author was led to conclude that the main structures are due to igneous flow, and that the most marked gneissic structure occurs where previously foliated sedimentary and igneous material has been incorporated with an invading granite. The patches of foliated gneiss in the granites of Donegal are thus remnants of considerable masses of older rock that have been absorbed ; and the phenomenon of banded gneiss arises characteristically as a marginal feature of granite domes. Foliation is found in surrounding masses parallel to that in the granite, and at the same time parallel to the surface of junction, for the simple reason that the granite has picked off, leaf by leaf, the layers of foliated rock against which it rose. The author thus ranges himself with those who ascribe the most profound metamorphism to igneous rather than to dynamic action, and ventures to suggest that similar conclusions may be drawn from the rocks of the Malmesbury series in the west of Cape Colony, where a commingling of rocks appears to have taken place during a period of subterranean flow. T].—Maematic Srcrecarion or Sutpuipe Orus. By Dr. A. P. CoLEMAN. fF\HE formation of ore bodies by magmatic segregation in eruptive rocks has long been admitted as regards magnetite and titaniferous iron ores, but the formation of sulphide ore bodies in this way has been disputed by many geologists. The pyrrhotite ores of nickel in Norway were first recognised by Professor Vogt as having this origin ; and his theory has been applied to the Sudbury nickel ores by various geologists, and opposed by others. The recent complete mapping of the eruptive sheet, with which the Sudbury ore bodies are all connected, proves that they are really 1 « Kyolution of Earth Structure,” p. 28. Notices of Memoirs— Geology of South Victoria Land. 81 segregated from the eruptive rock and form an integral part of it, with every gradation between ore and rock. It is believed that gravitation played a large part in the segregation, since the ore bodies are regularly found at the lowest points in the lower edge of the norite-micropegmatite sheet with which they are connected. IlI.—On tHE Geronocy or Sourn Victoria Lanp. By H. T. Frrrar, M.A. I. The knowledge we had of South Victoria Land previous to the departure of the “‘ Discovery ” was mainly acquired by the expedition under Sir James Clarke Ross in H.M.S. “Hrebus”’ and H.M.S. “Terror,” in the years 1839-1843. His discoveries may be briefly summed up thus :— (a) A great range of mountains, which rise occasionally to heights of 15,000 feet, and extend in a north and south direction for at least 500 miles. (b) The presence of volcanic and plutonic rocks in this area. (c) An open shallow sea south of the Antarctic circle. (d) An active volcano, Mount Erebus, over 12,000 feet high, emitting flame and smoke in great profusion. (e) A wall of ice, the Great Ice Barrier, on an average 150 feet high and about 470 miles long. In 1899 the ‘Southern Cross” expedition brought home from Cape Adare specimens of granites, basalts, and quartz slates, but unfortunately the latter proved to be unfossiliferous. II. This section deals with the volcanic islands off the coast, commencing with the Balleny Group, in latitude 66° S., and passes on to the rocks of the mainland in latitude 77° 8. The rocks from the islands are chiefly basalts and tuffs, though intrusions of trachyte are fairly common. Edward VII Land and the volcanoes on the mainland are included in this section, as the latter, at any rate, belong to the recent volcanic eruptions of the area. All the volcanoes are undenuded cones, and are usually situated in isolated positions, and contrast strongly in outline with the rugged scenery of the main mountain range. Ill. The Continental Range. The great range of mountains discovered by Sir James Ross has been proved to be at least 800 miles long, and to have some remarkable features common to the whole length. This great mountain range is divided into smaller ranges, to which distinguishing names have been given; but only one, the Royal Society Range, has been examined in detail by the expedition. The rocks that compose the range are conveniently separated into four distinct groups—namely, gneisses, granites, sandstones, and dolerites. The sandstone, to which I propose to give the name Beacon Sandstone Formation, provides a convenient stratigraphical datum-line, with reference to which the other phenomena may be considered. (i) The Gneissic Rocks occur at sea-level and below a sequence of _ rocks which is at least 12,000 feet thick, and may be safely regarded DECADE V.—VOL. III.—NO. II. 6 82 Notices of Memoirs—E. T. Mellor— as forming the ancient platform on which the central part of South Victoria Land is built. The foot-hills of the Royal Society Range and the lower portions of the Cathedral Rocks are composed of this class of rock. (ii) The Granites have been encountered at the north end of the Royal Society Range, where they rest upon gneisses, and dykes of granite pierce the gneissic series. At Granite Harbour this type of rock is found as a huge boss, and is probably covered by a sheet of dolerite. Where the Ferrar Glacier forks, a junction of dolerite and granite proves that there are two distinct developments of granite, one older and one younger than a certain sheet of dolerite. (iii) The Beacon Sandstone Formation is met with at a height of 4,000 feet above sea-level, and about 40 miles from the sea. It appears to be nearly 3,000 feet thick, and near the top indeterminable fossil plants were found. The bedding is practically horizontal, and the rock is remarkably uniform in texture. The surface upon which it rests has not yet been discovered. (iv) The Dolerite Sheets produce the plateau features characteristic of that rock, and cap the sandstone over a very large area. Dykes, sills, and pipes of the dolerite occur in the sandstone, and prove the former to be intrusive. The original dolerite plateaux have been dissected by water action, apparently prior to the faulting which has dislocated the Beacon Sandstone. IV. The Ice. Sea-ice, produced by the freezing of the sea during the Winter, is on an average 8} feet thick, but during the Summer the sea-water melts the lower surface of the ice. Shore-ice, a fringe of glacier ice attached to the land, shows the conservative action of ice in this latitude. Inland ice, local ice-caps, piedmonts, and other types of glaciers may be recognised in South Victoria Land. The term ‘floating piedmont’ has been suggested as descriptive of the Great Ice Barrier, or Ice Sheet, of Ross, and there are at least three examples in our area. The moraines high on the slopes of Mount Erebus, and other moraines stranded at various spots, are considered in their relation to the past and present distribution of the ice, and the conclusion arrived at is that the glaciation is approaching a minimum. IV.—EvipEnoes oF GuactaL ConpitTions In Permo-CARBONIFEROUS Times 1n THE TransvAaL. By Epwarp T. Metxor, B.Sc. [Communicated by permission of the Director of the Geological Survey of the Transvaal. ] fY\HE present paper gives a brief account of recent work in connection with the rocks at the base of the Karroo System in the Transvaal, including some additions to the evidence of extensive glacial action in early Karroo times. The description given of the character and mode of occurrence of the glacial conglomerate is based mainly upon observations made in the course of mapping a district lying between the Elands and Wilge Rivers, east of Pretoria. The Karroo System does not here attain so Permo-Carboniferous Glaciation in Transvaal. 83 complete a development as in the more eastern and southern portions of South Africa. The whole thickness of the formation rarely exceeds 400-500 feet, and it is not possible as yet to recognise the many divisions which it presents in those parts of South Africa where it attains a much greater thickness. Outliers along the margin of the main area occupied by the Karroo System afford good opportunities for the study of the glacial conglomerate which forms its base. They are occasionally entirely composed of this con- glomerate owing to the complete denudation of the overlying sandstones and grits. The upper and well stratified portion of the formation lies every- where horizontally, and its base maintains a very constant elevation of about 4,900 to 5,000 feet. The glacial beds of the lower portion of the formation rarely show distinct stratification, and outliers consisting of these alone closely resemble, both in appearance and mode of distribution, patches of glacial drift of comparatively recent origin. ‘There is abundant evidence that they were laid down upon an old land surface possessing considerable variety of surface feature, and some of the thickest deposits of glacial conglomerate occur in valleys or below escarpments which were in existence before its deposition. Owing to the abundant sandy drift arising both from the con- glomerate itself and from the grits and sandstones which usually overlie it, the solid conglomerate is rarely exposed at the surface. Where seen, it is of a light yellow or cream colour, and usually consists of a sandy-looking matrix containing abundant boulders and pebbles distributed without definite arrangement through the mass. The pebbles and boulders vary in size from 2 to 3 inches up to as much as 10 feet in diameter. The materials of which the boulders are composed vary much in character. There is always a great preponderance of local rocks, with an admixture of others which can be shown to be derived from comparatively distant sources, which are to the north of the present position of the boulders. In the district here specially referred to, the majority of the boulders consist of hard red quartzites and conglomerates derived from the Waterberg Formation, which underlies the glacial conglomerate over a large part of the area. Almost equally numerous are boulders of the Red Granite, which occurs extensively further to the north. The boulders are always highly polished and usually facetted. When composed of fine-grained rocks, such as felsites and shales, they frequently show striations on the facets. The matrix of the glacial conglomerate consists of sharply angular fragments of quartz and of rocks similar to those of which the boulders are composed, varying in size from mere grains upwards. It differs to some extent from the matrix of the typical Dwyka conglomerate of the more southern portions of South Africa in presenting an appearance much less suggestive of an igneous origin. By weathering, the matrix of the conglomerate usually gives rise to sandy products; in some localities, however, it produces a yellowish clay, in which the boulders remain embedded. In specimens from a depth, the matrix 84 Notices of Memoirs—E. H. L. Schwars—Baviaan’s Kloof. is occasionally greenish in colour. Locally there occur in the conglomerate lenticular patches of fine-grained, massive, white or cream-coloured sandstones, and white, finely laminated shales and mudstones. The progressive denudation of the glacial conglomerate exposes at its margin the glaciated surfaces of the underlying rocks, which frequently show very clear striation. The best examples yet met with are those occurring to the north of the Douglas Colliery near Balmoral. In a number of examples distributed over an area of 300 square miles the stria exhibit great constancy of direction, and point to the existence of an extensive ice-sheet with a movement from N.N.W. to 8.8.E. It is very probable that the glacial conglomerate extends very much further north than the localities at present known. During the past year outliers of the conglomerate were found ninety miles north of the latitude of Johannesburg. V.— Tue Puvronto Rooks anp tTHErR RELATIONS WITH THR JRYSTALLINE Sonrsts AND oTHER Formations. By F..P. MENNELL. T has been pointed out by Teall that the final solution of the problems arising in connection with the origin of igneous magmas is possibly to be looked for where the plutonic rocks are Seen in their relations with the crystalline schists. The writer dealt with observations made in such an area and the inferences to be drawn therefrom. He concluded that the average igneous rock has practically the composition of the average granite, and that plutonic rocks are immensely more important than the other classes, even when the term plutonic is used in a much more restricted sense than by many authors. The causes of variation were discussed, and segregation, except as a phenomenon of limited importance, was dismissed as an untenable theory. The origin of the magmas must be considered in order to account for subsequent variation. ‘Refusion’ seems the only possible mode of formation. Granite appears to result from the effective mixing of the heterogeneous materials melted down, other igneous rocks being the result of the cooling of different parts before mixture is complete, basic material having also the best chance of reaching the surface as lava, owing to its superior liquidity. There is circulation of material between the igneous and sedimentary rocks, the material analysed in the latter being subjected to synthesis in the making of the former. VI.—Bavraan’s Knoor: the object only of mapping the glacial drifts and other superficial deposits. The older geological formations include the Lower and Upper Old Red Sandstone (termed on the previous Geological Survey map the Dingle and Kiltorcan Beds) and the Carboniferous Limestone Series. The boundaries that mark the exposed limits of these older rocks are reproduced from that Survey; and the only notable change is the abolition of the term ‘Coal-measures?” which strangely enough was used for beds now grouped as “Upper Shale or Posidonomya Becheri Beds.” So much interest attaches to the relations of these Old Red and Carboniferous beds to the equivalent strata in the west of England and South Wales, that it is a matter of regret that the attention of Mr. Lamplugh and his associates was confined (officially) to the mapping of the superficial deposits. In consequence we have to be content with a good deal of information gathered more than fifty years ago, as the district was surveyed by Jukes and his staff in 1851-2; while the explanatory memoir on Sheets 187, 195, and 196, owing to ‘“‘ the inadequate means afforded us to carry out our work to completion,” was not issued until 1864. 88 Reviews—Geological Survey of Canada. Needless to say, there is much of interest in the remarks of Jukes on the Old Red Sandstone, Devonian, and Carboniferous rocks in that old memoir, which deals with a large part of the area described in the work before us. Until the new survey was carried out our knowledge of the Glacial Drifts of the district was meagre, and the greater part of the present memoir is occupied with a general and detailed description of the raised beaches, ‘head,’ boulder-clay, glacial sands and gravels, old river gravels and deltas, and other superficial deposits. The story told by these complex accumulations has been most ably and skilfully disentangled; and we commend its perusal to our readers. The pre-glacial or early glacial shore-line discovered by Messrs. Muff & Wright near the mouth of Cork Harbour consists of a rock-shelf, on which there rests in succession raised beach, blown sand, ‘head’ or talus, boulder-clay, and an upper ‘head.’ The ancient shore-line is distinctly older than the glaciation of any part of the south or south-east of Ireland. The present river valleys, the origin of which was discussed in a classic paper by Jukes, were mainly of pre-glacial age. The valley system of the interior has been only slightly modified, and the present sea-inlets have been brought about by depression whereby the lower parts of the valleys were submerged. The memoir is well illustrated with photographic plates and other figures, and it contains a useful chapter on economic geology. IV.—Gerotocioat Survey or Canapa. By Roserr Bett, I.8.0., M.D., F.R.S., Acting Director. Part O, Annual Report, vol. xiv. The Artesian and other Deep Wells on the Island of Montreal. By Franx D. Apams, D.Sc., F.G.S., and Osmonp E. Luroy, M.Sc. 8vo; 74 pp. (Ottawa: 8. E. Dawson, 1904.) HE objects kept in view by the authors of this able report were, in the first place, to describe as completely as possible all the borings put down in the Island of Montreal up to the close of the year 1908, and secondly, to ascertain, if possible, whether any definite water-bearing horizons existed in the underlying rocks, and by a study of the geology of the district to learn the character and origin of the subterranean water supplies and the prospect of obtaining water by further borings. Highty-nine boreholes were found to have been made during the period covered by the report. Only six of these were, however, actually flowing, that is artesian wells, most of the Montreal wells requiring to be pumped. A tabulated list specifies the depth in feet of the borings, the diameter of the holes in inches, the capacity per diem in gallons (much higher than that usually required), the character of the water, hard, soft, saline, etc., together with the names of the owners, location of the borings, and other details. A careful description of each boring follows this list, from which it is seen that most of the wells yield potable waters, while some of them are hard, owing to the presence of a considerable quantity Reports and Proceedings—Geological Society of London. 89 of lime or magnesia salts, thus rendering them unsuitable for use in steam boilers. Others, being impregnated with sulphurous com- pounds, or possessing a saline character, are only of use for cooling purposes. Analyses of the waters have been made from time to time, but these having been prepared merely for technical purposes are in most cases incomplete. A comparative examination -of them, however, brings out some interesting points bearing upon their chemical composition in relation to the rocks from which they were derived. Regarding the course of the underground waters supplying the numerous wells sunk in the thickly-bedded (Ordovician) limestones in the Island of Montreal, the authors conclude that the channels through which the waters flow have the form of irregular fissures, and that “there is no distinct water-bearing horizon in the form -of interstratified permeable beds.” The proof of this is to be found in the circumstance that both the supply and the character of the water differ in borings in comparatively close proximity to each -other. The irregular course of the waters is partly influenced by the presence of abundant dykes and sheets of impervious igneous rocks traversing the limestone strata in every direction. A very moderate estimate shows that the wells already bored would yield, if pumped to their full capacity, 2,500,000 gallons per diem, which is nearly one-tenth of the daily average pumped by the Montreal Water Works for the use of the city. The source of the underground water is considered to be in all probability the higher portion of the plains along the flanks of the ‘Laurentian country in the north-western part of the Island of Montreal. This valuable report is illustrated by diagrams in the text, and by (1) a geologically coloured map of the Island of Montreal and its vicinity, (2) a topographical map of the city of Montreal with the positions of the borings, (38) graphic diagrams showing the relations of certain groups of wells in the city of Montreal and its vicinity. Artuur H. Foorp. ISIS OISeS) | ANAND) aS Ima DALAN (ETS —_»—_—_ GEOLOGICAL Socrety or Lonpon. ‘I.—December 20th, 1905.—J. E. Marr, Sc.D., F.R.S., President, in the Chair. The following communications were read :— 1. “The Highest Silurian Rocks of the Ludlow District.” By Miss Gertrude L. Hlles, D.Sc., and Miss I. L. Slater, Newnham College, Cambridge. (Communicated by Professor T. McKenny Hughes, M.A., F.R.S., F.G.S.) After an introduction dealing with previous work in the district, ‘the authoresses adopt the following classification of the beds :— 90 Reports and Proceedings—Geological Society of London. Feet. B. Temeside or Zuwry- 110 to 120 Zone of Lingula cornew III. Temespe pterus Shales ee and Hurypterus. Group. )A. Downton Castle aa 30 to 50 { Zone ot Lingula Yellow Sandstone | minima. Cae |, Bt ARERR as 0 Zone of Cla LupLow are : E A. Lower Whitcliffe or ) (Zone of Rhynchonelle Goaee Rhynchonella Flags § pice #20 U nucula TA Aqaaeene B. Rae: or Dayta\ 49%0150 Zoneof Dayia navicula. Grover. )A. Aymestry or Con- \ 75 to 250 § Zone of Conchidium chidium Limestones § U Knightii. 516 to 850 A brief outline description of the main subdivisions is first given, as they appear when followed from Ludlow southward to Overton, eastward to Caynham Camp, westward to Downton-on-the-Rock, and northward to Bromfield, and also near Onibury and Norton. The main tectonic features of the district appear to be due to the superposition of Armorican movements in rocks with a Caledonian trend, held by some rigid mass to the north, presumably the Longmynd massif. A detailed description is then given of the succession, as seen at the following localities: River Teme, Wigmore Road, Deerhouse Bank, Caynham inlier, the Teme and north-east of the Castle at Downton, Downton Castle inlier, Mocktree, and near Onibury on the Craven Arms Road, the Onibury Norton Lane, and at Norton. The paper closes with a detailed list of fossils obtained by the authoresses, supplemented by the collection in the Ludlow Museum. 2. “The Carboniferous Rocks at Rush (County Dublin).” By Charles Alfred Matley, D.Sc., F.G.S. With an Account of the Faunal Succession and Correlation. By Arthur Vaughan, B.A., D.Sce., F.G.S. Rocks of the Carboniferous Limestone Series are exposed along 5 miles of coast near Rush, Loughshinny, and Skerries, in county Dublin. The present paper deals only with the beds near Rush, in the southern portion of this tract, where about 2,500 feet of the series are exposed, without allowing for gaps in the succession. The upward sequence is (on the whole) from south to north, and the range is from the Upper Zaphrentis to the Upper Dibunophyllum Zone. The Rush Slates are the lowest beds, 1,380 feet thick, but their base is not visible. They consist of black and dark-grey, well- cleaved argillaceous, and less perfectly cleaved calcareous, slates ; and they contain bands and nodules of limestone. The peculiar outcrop of some of the limestone bands is described, and instances. of cataclastic structure are noticed. The characteristic fossil is. Zaphrentis aff. Phillipsii. The Rush Conglomerate Group succeeds the Rush Slates, after a short interval of passage-beds. It is 500 feet thick, and consists of well-bedded alternations of conglomeratic, pebbly, and sandy limestones, with shales and calcareous flaggy beds. Ordovician Reports and Proceedings— Geological Society of London. 91 and Silurian rock-fragments abound in them, together with many inclusions of Carboniferous Limestone. The group is shown to be of the same age as the Pendine Syringothyris conglomerate and the volcanic rocks of Weston-super-Mare, and its existence indicates. that the movement and disturbance in Mid-Avonian times extended over a considerable area. The beds above the conglomerates are mainly limestones and calcareous shales. They are thrown into numerous sharp folds, and are occasionally inverted. The highest beds seen (Cyathaxonia Beds) are correlated with the Hastern Gower or Oystermouth Lime- stone of the South-Western Province ; but the fauna agrees still more closely, and is identical, with that of the highest Avonian beds of the Midlands of England, at Parkhill, Wetton, Thorpe Cloud, etc. The disappearance by solution of a considerable thickness of limestone is described. A list is given of the fossils from a large number of horizons in the Rush Series (which is divided into the Zaphrentis, Megastoma, and Cyathaxonia Beds), as well as of the fauna of the Curkeen Hill Limestone, near Loughshinny, the horizon of which is assigned to the Upper Dibunophyllum Zone, probably below the Cyathaxonia Beds. The paleontological section deals only with Brachiopods and Corals. In that part which deals with the Brachiopods the inter- relationship of the various members of the more important gentes is discussed in considerable detail. In the part which is devoted to the Corals a new subgenus is suggested, and four new species are described. Professor G. F. Wright, in exhibiting a map of the Lebanon district, gave an interesting description of the evidence which he found, in a recent journey to that district, as to the height and extent of the terminal moraine. He remarked also that the water- level in the Jordan Valley stood, in comparatively recent times, 750 feet higher than at present, and this he connected with the glaciation of the area. Very small climatic changes would be sufficient to start the Lebanon Glacier again. II.—January 10th, 1906.—J. E. Marr, Se.D., F.R.S., President, in the Chair. The following communications were read :— 1. “The Clay-with-Flints: its Origin and Distribution.” By Alfred John Jukes-Browne, B.A., F.G.S. Until recently the Clay-with-Flints has been regarded as being, in the main, a residue from the slow solution of the Chalk. This was the explanation proposed by Mr. W. Whitaker in 1864, although he admitted that the deposit included some material derived from the Eocene. Writing in 1865, Mr. T. Codrington thought that an overlying stratum of clay or loam was essential to the formation of Clay-with-Flints. Lastly, Charles Darwin in 1881 seems to have taken it for granted that it was solely a residue 92 Reports and Proceedings—Geological Society of London. from the Chalk. Of late years the opinion has been growing that it consists very largely of material derived from the Hocene. The present paper is devoted to an examination of the facts, with the view of ascertaining whether the Clay-with-Flints could possibly be derived from the Chalk, or whether the theory of its derivation from the Eocene is confirmed by more detailed enquiry. The author first describes its composition, noting that unbroken flints are not everywhere abundant, that broken angular flints are common, and green-coated flints are not rare; finally, that if the clay is washed it always yields a residue of sand, composed chiefly of rounded quartz-grains with some of iron-oxide, and both apparently derived from the Hocene sands. The thickness of the accumulation is next discussed, especially with reference to sheets of it that lie on fairly even floors. In such positions it varies from 2 to 12 feet in depth, and large areas occur where it must have an average depth of 3 or 4 feet. The products resulting from artificial solution of chalk are then considered, and a series of analyses is given, from which the average amount of insoluble residue existing in the four lower zones of the Upper Chalk is deduced. Experiments have been made by Mr. Williath Hill to determine the related weights of a cubic foot of Upper Chalk and a cubic foot of Clay-with-Flints, in order that allowance might be made for the difference in calculating the quantity of clay which would be left by the solution of a given quantity of chalk. The result shows that 100 cubic feet of the Jlicraster coranguinum Chalk will produce only 1:2 cubic feet of clay, and the solution of the arsupites and Jficraster coranguinum Zones to the extent of 200 feet over any part of the area would only yield clay enough to make a layer 2 feet deep. Lastly, it is shown that the quantity of flints in the Upper Chalk is so much greater than the quantity of clay that the natural residue could not form a Clay-with-Flints. Thus, solution of 100 feet of Micraster coranguinum Chalk would yield a bed of flints about 7 feet thick, and only enough clay to fill up the interstices between the nodules. The next section is devoted to the distribution of the Clay-with- Flints, and its stratigraphical relations to the Chalk on the one hand and to the Eocene on the other. In dealing with this part of the subject, details are restricted to the areas lying west and north-west of the London Basin and to the wide area between the London and Hampshire Basins. From these several lines of investigation the author coneludes :— (1) That the Clay-with-Flints cannot have been formed from mere solution of the Upper Chalk; (2) that all its components, except the unbroken and angular flints, could have been furnished by the Reading Beds; (8) that the positions occupied by it are such that no great thickness of Chalk can have been destroyed to form it, the tracts being seldom more than 380 or 40 feet below the local plane of the Eocene base, or the presumed level of that plane. Finally, an attempt is made to explain the manner in which the Clay-with-Flints was formed, and the theory adopted is that the - Correspondence—A. J. Tukes-Browne. 93 outlying Hocene tracts, which were in existence during late Pliocene time, were broken up and spread out by the severe climatic conditions of the Glacial Period. In post-Glacial time little has. been added, but much removed by erosion. 2. “On Footprints from the Permian of Mansfield (Nottingham- shire).” By George Hickling, B.Sc. (Communicated by Professor W. Boyd Dawkins, D.Sc., F.R.S., F.G.S.) These fossils were discovered in 1897 by Mr. Francis Holmes in the Rock Valley Quarry, Mansfield, in a local lenticular mass of sandstone intercalated in the Magnesian Limestone. The impressions formed two double rows, approximately parallel, and 7 and 2 feet long respectively. Nearly the whole of the longer series is in the Nottingham Museum, and part of the shorter series in the Manchester Museum. Both sets were made by the same species of animal, the stride in one case being 8 and in the other 8? inches. The prints show a well-marked heel and comparatively slender digits, and there is evidence of a membrane between the toes. There is wide separation between the right and left sides, this separation being more marked in the fore than in the hinder footprints. The prints present some resemblance to those named Ichnium acrodactylum, from the Upper Permian of Thuringia. Recently the author has. found other prints in the same quarry. CORRESPONDENCE. THE ZONE OF OSTREA LUNATA. Srr,—I am very glal that Mr. Brydone is publishing his further observations on the Chalk bluffs of Trimmingham, and it is clear they will throw valuable light on the much disputed question of the manner in which these masses were brought into their present positions. I am sorry, however, that he should object to my choice of Osirea lunata as the index-fossil for the zone which his previous observations enabled me to establish on a firm basis; the more so as his reason for objecting to the choice seems to me to have little force. He admits that O. lunata “has two characteristics of an ideal name-fossil in that it is, as far as we know, almost confined to the Trimmingham Chalk, and that in that chalk it always occurs abundantly if at all.” He thinks, however, that ‘it fails to fulfil the most important requirement for a good zone-fossil in that it is not distributed all through its so-called zone.” Moreover, Mr. Brydone seems so sure that O. lunata will not do as an index that he proposes to rename the beds as the “zone of Terebratulina gracilis and T. Gisei,” in spite of the most obvious objections. JI am therefore compelled to defend my choice of a zone- name from his attack upon it. In the first place I must ask Mr. Brydone why he asserts that the 94 Correspondence— Clinton G. E. Dawkins. index-fossil of a zone must be distributed ‘all through its zone,” and what he means by this expression. I am sure that he does not expect to find the chosen fossil in every foot of the chalk which makes up the zone. I suppose, therefore, he means that it ought to oceur at frequent intervals throughout the zone, and that the total thickness of beds in which it does occur should be greater than that of those in which it does not. I greatly wish that fossils would occur in such a well-regulated manner, but unfortunately their behaviour often falls sadly short of what we should like it to be. Mr. Brydone must surely have forgotten that Marsupites is not a common fossil throughout the zone of which it is accepted as the index. In fact, it is common only in the Marsupites band or subzone, and is rare or absent in the Uintacrinus band. Yet I am not aware that anyone has objected to its being used as the index-fossil of the zone, and I sincerely hope that no such objection will ever be taken. Again, has Mr. Brydone considered the case of the zone of Act. quadratus, where that species (as now restricted) only occurs rarely, especially in the higher part of the zone. It is true that Mr. Rowe has proposed to take Offaster pilula as the index-fossil, because it is common throughout, but this generally occurs at intervals only, being common in spots or in bands and rare or absent in the inter- mediate beds, just as Ostrea lunata seems to be absent from certain beds in the Trimmingham Chalk. From the succession of beds given by Mr. Brydone on p. 14 of this Magazine, and assuming his group 38 to be identical with part of his group 4, it is seen that O. lunata occurs abundantly at four horizons in the series, and that it occurs in all three divisions. This is quite sufficient to satisfy all reasonable demands on any fossil for qualification as the index of a zone; consequently I must maintain the propriety of my choice, and must object to any other species being substituted for Ostrea lunata, unless a much better reason can be given than that advanced by Mr. Brydone. A. J. Jukres-Browne. Froriston, Torquay. DISCOVERY OF EXOGYRA SINUATA IN THE LOWER GREENSAND OF CULHAM, NEAR OXFORD. Sir. —It might interest your readers to hear of the finding of a specimen of Exogyra sinuata by Mr. W. D. Hutchinson and myself in the Lower Greensand of Culham, near Oxford. The specimen is a large one, and was found in a bed of coarse laminated sandstone, in a neighbourhood where the Greensand has been considered unfossiliferous. Cuinton G. E. Dawkins (Balliol College, Oxford). 6, LarksToNE TERRACE, ILFRACOMBE. Obituary—Charles Tookey, F.I.C., F.C.S. 95 @rS ew eARE Na CHARLES TOOKEY, F.1.C., F.C.S. Born May 13, 1828. Dirp January 3, 1906. WE regret to record the death of Charles Tookey. He was born at Oddingley Rectory in Worcestershire, and educated at Bromsgrove School; he became a student at the Royal College of Chemistry in 1851, and was an assistant in the following year. In 1854-5 he was assistant to Dr. Stenhouse at St. Bartholomew’s Hospital, and from 1856 to 1865 assistant to Dr. Percy at the Royal School of Mines. During this period he analysed examples of iron-ore from South Staffordshire for part 2 of “The Iron Ores of Great Britain,” 1858 (Mem. Geological Survey). In 1865 he was appointed Assayer in H.M. Mint at Hong Kong, a post which he relinquished in 1868. From 1870 to 1874 he was Assayer, Chemist, Superintendent of Refinery, and Temporary Director at the Japanese Imperial Mint at Osaka. On his return to this country he served 1874-8 as Chemist on the Admiralty Boiler Committee. He was author of papers “On the Separation of Tin from Antimony, and on the analysis of alloys containing Lead, Tin, Antimony, and Copper” (1862) and “On the Manipulation of Assays of Gold and Silver Bullion” (1870), Journ. Chem. Soe. We are indebted for most of the above particulars to the “Register of the Associates and Old Students of the Royal College of Chemistry, the Royal School of Mines,” etc., by T. G. Chambers, 1897. DM TIS \ GAs Esa IN PIs) OS - oe RETIREMENT OF Dr. B. N. Peacu, F.R.S. In September last Dr. B. N. Peach, F.R.S., retired from the Geological Survey after a period of 43 years service. Joining the staff in 1862 as assistant geologist, after a distinguished career at the Royal School of Mines, he was engaged for the first few months in determining Carboniferous fossils from the county of Fife under Salter’s supervision in the London office. When favourable opportunities presented themselves during his subsequent career, he pursued this branch of research with keen fascination, impelled by the instinct of the naturalist, which he inherited from his gifted father. In the same year he was attached to the field staff in Scotland, then under the direction of Sir Andrew Ramsay, and in 1867 he was appointed geologist when a separate staff was organised for the northern part of the kingdom under the Directorship of Sir A. Geikie. Throughout his long career it has fallen to his lot to take a prominent part in mapping all the Paleozoic formations in Scotland, together with large areas of crystalline schists of the 96 Miscellaneous—Retirement of Dr. B. N. Peach, F.R.S. Highlands. In particular, the detailed work in the complicated region in the west of Sutherland and Ross was carried out under his immediate supervision. It is within the mark to state that no geologist has acquired such a thorough mastery of the details of Scottish geology, exclusive of the rocks of Secondary and Tertiary age. In 1879, after Mr. Etheridge, jun., had joined the geological department of the British Museum under Dr. H. Woodward, F.R.S., Dr. Peach, in addition to his field duties, was appointed Acting Paleontologist on the Scottish staff. He was thus furnished with opportunities which he long had in view. He devoted special attention to the Paleeozoic Arthropoda, and in addition to his purely official work he published papers in the Transactions of the Royal. Society, Edinburgh, the Geological Society, London, and the Royal Physical Society, Edinburgh. Among these papers we may par- ticularly mention those dealing with the fossil Scorpions of the Carboniferous and Silurian rocks of Scotland, and with the fauna of the Olenellus-zone of the North-West Highlands. But the incessant demands of field work prevented him from carrying out his investigations as fully as he had hoped. At present there are about 2,000 specimens of the higher Crustacea of the Carboniferous rocks of Scotland in the Geological Survey collections, some of which have been figured and described by Dr. Peach. But many new forms are still undescribed, and in the interests of Scottish geology it is to be hoped that an arrangement will be made whereby he will be enabled to complete this research. In recognition of his eminent services to Scottish geology, of the assistance which he has generously rendered to other investigators, of his inspiring influence on the younger members of the Survey staff with whom he came in contact, his many friends have resolved to present him with a substantial testimonial, towards which about £100 has been already subscribed. This testimonial will be pre- sented to Dr. Peach at a public dinner to be held in Edinburgh on March 30th, 1906. Corricrenpa.— We have been requested to state that, in the article on Professor T. McKenny Hughes in the January number, in the list of distinguished students, Miss Elles should have been described as “ Assistant Demonstrator in the Geological Museum,” instead of ‘ Assistant to the Woodwardian Professor,” Mr. F. R. C. Reed having held the latter post since 1892. The degree of D.Sc. held by Miss Elles was conferred upon her by the University of Dublin in July last, and upon Miss Wood by the University of Birmingham at the same date. No doubt the University of Cambridge will, in time, become equally liberal in conferring degrees upon women.—Epir. Grou. Maa. Erratum. — Mr. C. Davies Sherborn writes :— Please correct a misprint in Grou. Mac., January, 1906, p. 34, nine lines from bottom ; I refer there to Nereitopsis (the worm), after JVereis, not to Neritopsis (the mollusc). NA No. 501. Decade V.—Vol. III.—No. III. THE GROLOGICAL MAGAZINE | > Monthly Jounal of Gealegn. WILTH WHICH IS INCORPORATED “THE GRHROLOGIST.” EDITED BY HENRY WOODWARD, LL.D., F.R.S., F.G.S., ASSISTED BY dic. WILFRID H. HUDLESTON, F.R.S., &c., Dk. GEORGE J. HINDE, F.R.S., &c., anv HORACE B. WOODWARD, E.R.S., &c. J. OrterinaL ARTICLES. The Geological History of South Africa. By Dre EF. Ho Harcu, F.G.S.,. M.1.C.E., President of the Geo- logical Society of South Africa...... The Physical History of the Great Pleistocene Lake of Portugal. By Professor Epwarp Hutt, LL.D., Tidal Deal Coat ease icy ane ee Fossil Corals from Eastern Egypt, Abu Roash, and Sinai. By Prot. J. W. Greeory, D.Sc., F.R.S., Glasgow University. (Concluded.) _ Allotropic Forms of Silica as Con- stituents of Igneous Rocks. By Cosmo Jouns, M.I.Mech.E.,F.G.S. The Thickness of the Ice-Cap in Glacial Periods. By Exnsr H. L. Scuwarz,A.R.C.8.,F.G.S., Rhodes University College, Grahamstown, SUG UPARETLG Bint ers ante cen ssi saws eh. Further Notes on the Trimmingham Chalk, Norfolk. (Concluded.) By R. M. Brypons, F.G.S. (Plates pve lelilesine Xe) cher sta sscnie. scekases stew eres Page 97 104 MARCH, 1906. (CO) aN ae) Jah IN Bees OriGINAL ARTICLES (continued). Page A Method of Classifying Igneous Rocks by their Chemical Composition. By Dr.HucH Wartu. (WithaTable.) 131 Il. Reviews. Catalogue of the Fossil Plants of the Glossopteris Flora. By E. A. Newell Arber, M.A., F. BGS es fire ata sao ase tase eee eee Guide to the Fossil Reptiles, Am- phibians, and Fishes in the British Museum (Natural History). (Plate ONT) Pete Sastectssr ee ocldneae gatas hae III. Rerorts anp PRocEEDINGs. Geological Society of London— January 24th, 1906 Bebruarya(thitcemancese. 2. icae eee Mineralogical Society of London ...... IV. CorrEesPponDENCE. Machine-made Implements. By F. J. Bennett, F.G.S. Ce i ay LONDON: DULAU & CO., 37, SOHO SQUARE. Price 1s. 6d. net. | iw The Volume for 1905 of the GEOLOGICAL MAGAZINE is ready, price 20s, net. Cloth Cases for Binding may be had, price 1s. 6d. net. ROBERT F. DAMON, WEYMOUTH, ENGLAND, Is now supplying carefully prepared Coloured Casts of the AUSTRALIAN MUD FISH, FROM THE RIVERS OF QUEENSLAND, -CERATODUS FORSTERI, KREFFT, Measuring 38ft. x 10in. = 9lem. x 25cm. 3 Price - £3. Also Casts of the upper: and lower halves of the Head, showing Teeth, Nares, etc., lying side by side on a slab, Measuring 10 in. x 6in. = 25cm. x 16cm: Price = £1 10s. ADDRESS : | ROBERT F. DAMON, WEYMOUTH, ENGLAND. THE GHOLOGICAL MAGAZINE. NEW. SERIES! DECADE Vv. VOL. Ill. No. III.— MARCH, 1906. @eEg as ee Al ee Aceleg ole le Sale ag ee I.—Tur Geroxocicat History or Sourn Arrica.! By Dr. F. H. Hatcu, F.G.S8., M.1.C.E., President of the Geological Society of South Africa. HE subject of this address is a brief account of the succession, thickness, and geological history of the South African, and more especially of the Transvaal, formations. The information necessary for such an account is of course very incomplete, but in broad outline the succession is now known, and some speculation as to the physical conditions that prevailed during the building up of the region may perhaps be permitted. I propose to deal with the period of the geological history of this country that came to an end with the close of Karroo times. The Karroo period ends with the Stormberg rocks (Rhetic), and since that time South Africa has, with the exception of a small coastal area, been a land surface, and the rocks have consequently been exposed uninterruptedly to the forces of denudation. 1. Order of Superposition of the Stratified Rocks. As is well known, no determinable remains of organisms have been found in the Transvaal below the Karroo Beds, and none below the Bokkeveld Beds in the Cape Colony. In the absence of fossil evidence, the succession can only be established by a careful observation of the order of superposition and the lithological character of the strata. The succession has already to a great extent been determined by various workers, and the main dividing- lines placed at the great breaks or unconformities that have been found to exist. Thus we have, as natural dividing-lines, five great unconformities, namely, that below the Dwyka Conglomerate (which for future reference we will call Unconformity No. V), that below the Waterberg Sandstone (Unconformity No. IV), that below 1 Presidential Address delivered by Dr. F. H. Hatch to the Geological Society of South Africa, 29th January, 1906. DECADE Y.—VOL. III.—NO. III. 7 EvropEAN EQUIVALENTS. 98 Dr. F. H. Hatch—Geological History of South Africa. the Black Reef Series (Unconformity No. III), that below the Ventersdorp System (Unconformity No. II), and that below the Witwatersrand System (Unconformity No. I). In regard to Un- conformity No. V, we have the exception that in Southern Cape Colony the Table Mountain Sandstone, which some of us regard as the representative of the Waterberg Sandstone, is followed successively and in strict conformity by the Bokkeveld, the Witteberg, and the lower shales of the Dwyka Series. The following order of superposition of the South African stratified rocks may be regarded as now fairly established :— SourTHERN Carr Cotony. oe ees ELS TRANSVAAL. ( Voleanic Group. \ Cave Sandstone. oes ae | Stormberg Redageds, | Missing. ; Karroo Molteno Beds. System. [Roe se - Missing. PERMO- CaRBONI- | Ecca and Dwyka = KEeca and Dwyka. FEROUS. (No. V.) Witteberg ... Missing. Sym, Bokkeveld «nse Missing. ~* (Table Mountain Sandstone == Waterberg Sandstone. (No. IV.) f Potchet- ( Pretoria Beds. stroom Dolomite Series. System. | Black Reet Series. (No. III.) DEVONIAN. Wontar Boulder Beds, Voleanic “i eal Breccias, Kliprivers- ae S. ae berg Amygdaloid, etc. ystem. \ Elsburg Conglomerates. (No. II.) Abeta ee ae rand Lower Witwatersrand System. Rode. (No. I.) ArcH#AN. Malmesbury Series ... = Swaziland System. With the exception of one or two points, which I shall proceed to deal with, the above succession has found general acceptance. One of the points about which there is some considerable difference of opinion is as to how much or how little of the Karroo System above the Dwyka Conglomerate is represented in the Transvaal. The view originally put forward was that the coal-bearing beds of the Transvaal were a continuation of the Stormberg Beds of the Cape. This was adopted by Molengraaff in his first geological reports; but later, in the course of a discussion as to the age of the coal beds which took place in the Society some two years ago, he came to the conclusion that our coal beds corresponded to the Beaufort Beds.’ Since then the conviction has grown amongst 1 Molengraaff, Discussion on Dr. Corstorphine’s paper ‘‘ The Age of the Central South African Coalfield’’: Trans. Geol. Soc. §. Afr., vol. vi (1903), p. 45. ° Dr. F. H. Hatch—Geological History of South Africa. 99 some of us that the Transvaal coal horizon corresponds rather to the Keca Beds. The present Director of the Transvaal Survey, however, has adopted Dr. Molengraaff’s view that the Hcca Series is not repre- sented at Vereeniging, the Dwyka Conglomerate being immediately followed by the Beaufort Series or Upper Karroo, as he terms it.? But, as militating against this view, I would point out that the Transvaal Coal-measures, while containing plant remains that are common both to the Heca and to the Beaufort Series (such as Glossopteris, Schizoneura, and Phyllotheca), have also yielded abundant specimens of two species which at the Cape have only been found in the Hcca Beds. I refer to Noeggerathiopsis Hislopt, which occurs both in the Middelburg Coalfield (Boschfontein) ” and at Vereeniging, and to Gangamopteris cyclopteroides, which occurs at Vereeniging.* Cardiocarpus,* which is associated with Gangamopteris and Glossopteris in Hceca Sandstone near Worcester, also occurs at Vereeniging. Moreover, to regard the Vereeniging Beds as of Beaufort (Upper Karroo of the Survey) age must involve the assumption of a considerable unconformity between the Dwyka Conglomerate and these beds, unless indeed we are to believe that the deposition of the glacial conglomerate took place at a much later date in the Transvaal than in the Cape Colony. A minor matter to which the attention of the Survey might be drawn is the nomenclature to be adopted for the Karroo System, for if the coal sandstones are to be regarded as corresponding to the Beaufort Beds of the Cape, then it will be much preferable to retain the name of Middle Karroo Series for them, since the term Upper Karroo is applied only to the Stormberg Beds at the Cape. Another difference of opinion between the Survey and some of us exists as to the unconformity beneath the Witwatersrand Beds ; and whether the latter form an independent system, or are but a portion of a more comprehensive system in which the granite is intrusive. The Director of the Survey is apparently not prepared at present to admit that there is in the Transvaal an older system than the Witwatersrand. He is not satisfied with the evidence that has been advanced that the Mont Maré schists are older than the Witwatersrand, nor that the Witwatersrand Beds are younger than the granite on which they rest.° In taking up this position he ignores the evidence as to the relative age of the granite and the Witwatersrand Beds furnished by Dr. Corstorphine® and the late 1 Kynaston, ‘‘ Geology of the Transvaal and Orange River Colony’’: Science in South Africa (1905), p. 298. 2 Seward: Q.J.G.S., 1897, p. 322. 3 Feistmantel, ‘‘ Uebersichtliche Darstellung der geologisch - paleeontologischen Verhaltnisse Stid - afrikas’?: Abhandlungen d. kénigl. bohm. Ges. d. Wiss., Folge vii, Band 3; Prague, 1889. * Seward: Q.J.G.8., 1897, p. 322. 5 Transvaal Geological Survey Report, 1904, p. 18. 8 G. S. Corstorphine, ‘‘ The Geological Relation of the Old Granite to the Wit- watersrand Series’’: Trans. Geol. Soc. 8. Afr., vol. vii (1904), pp. 9-12. 100 Dr. F. H. Hatch—Geological History of South Africa. Mr. Dérffel.! But what is the nature of the evidence that he would deem satisfactory to establish the relation of the Witwatersrand Beds to the granite ? They are seen in contact at numerous places, but nowhere is the latter found penetrating or sending off apophyses into the former. Neither do the sediments show anywhere any sign of contact metamorphism. On the contrary, they appear to have been accumulated on an ancient granite floor. Ifthe granite were later than and intrusive into the Witwatersrand Beds, surely some evidence of this would be forthcoming. It is true that Mr. Kynaston does not deny the possibility of an unconformable relation, but he records the evidence as insufficient. Now this is a question which affects the mapping of thousands of square miles of country; it is besides important to the public from a mining point of view. I will give an instance — bore- holes put down by exploration companies through the overlying covering of Karroo rocks or Dolomite are invariably stopped if they should reach the Granite. Is the doubt as to the usually accepted relation of the Granite to the Witwatersrand Beds so strong in Mr. Kynaston’s mind that he would advise the continuation of such boreholes? We unfortunate geologists and mining engineers, who have to take practical views of such matters, are not allowed the luxury of academic doubt. Further, the important question is involved as to the relation of the Witwatersrand Banket to the conglomerates and quartzites that occur in association with schistose rocks in the Barberton and Pietersburg districts, and in Swaziland and Mashonaland, a question which has recently been much dis- cussed, owing to the prominence given to the so-called banket occurrence at Lomagunda in Rhodesia, and its correlation with the Witwatersrand rock.? I maintain that instead of shelving questions like these, the Survey should investigate the facts, and establish definitely the relation of the Witwatersrand Beds to the Old Granite, and the existence or non-existence of an older system of sedimentary rocks. These are questions of vast importance to the mining industry, and call for as early a settlement as possible. While the maps produced by the Survey are a fit subject for congratulation there is room for a difference of opinion as to the line on which the survey work should be carried out. Personally I am of the opinion that in the present stage of the development of the country the most good would be done, not by giving us detailed maps (however excellent in themselves) of outside districts, but by settling the large questions which its Director holds still require solution. While on the subject of the Survey I will touch on another question, of the importance of which Mr. Kynaston is as fully cognisant as we are. The maps issued by the Survey since its reorganisation in 1902 cover an area of about 4,100 square miles. 1 D. Dérffel, ‘‘ Note on the Geological Position of the Basement Granite”: Trans. Geol. Soc. S. Afr., vol. vi (1903), pp. 104-105. 2 F. P. Mennell, ‘‘ The Banket Formation of Rhodesia”: Trans. Geol. Soc. 8. Afr., vol. viii (1905), p. 82. Dr. F. H. Hatch—Geological History of South Africa. 101 This is a very creditable performance considering the smallness of the staff. But a simple computation will show that at this rate of progress some 30 years will be required to finish the work unless the staff be augmented. The importance of rapidly com- pleting the geological survey of a country, dependent as this is for its future welfare on the development of its mineral resources, cannot be too strongly impressed on the authorities; and to accomplish it the staff must be largely increased. I am glad that we can welcome an additional field geologist in the person of Dr. W. A. Humphrey, who has had part of his training in South Africa, and we may trust that this is an augury of the Government’s recognition of the importance of the work, and of its intention to carry it out with the least possible delay. I will pass on now to a consideration of the data available for deducing the thickness of the South African formations. 2. Thickness of the Strata. Since we know neither the base nor the summit of the Swaziland system no estimate can be made of the thickness of these ancient rocks, which are partly of sedimentary, partly of igneous origin, but have in both cases been profoundly modified. There can be no doubt, however, that they are very thick, and that an immense quantity of material has been removed by erosion since their first upheaval. Recently, in a paper read before this Society, Dr. Voit has expressed the opinion that certain banded gneisses of the Northern Transvaal should be separated from the Swaziland system as an older fundamental gneiss, corresponding, say, for instance, to the Laurentian rocks of Canada and the Lewisian gneiss of Scotland. As, however, he describes no section from which the relation of these gneisses to the remainder of the Swaziland system can be inferred, and since it is by no means certain that these gneisses are anything else than a sheared or metamorphic portion of the granite, which in other places is found intrusive in the Swaziland Beds, it must be premature in the present state of our knowledge to attempt any such subdivision. With regard to the Witwatersrand System, the shales and quartzites of the lower division have on the Rand a thickness of 12,000 feet ; the upper division, if we exclude the Elsburg Series, about 7,000 feet ; in all about 19,000 feet. The necessity of separating the Elsburg Series from the Witwatersrand Beds, which was advocated by Dr. Corstorphine and myself in a paper on the Geology of the Bezuidenhout Valley, read before this Society, is again shown by fresh evidence from the Klerksdorp district, which will be made the subject of a paper by Mr. Torissen. This series of conglomerates and quartzites has on the Rand a thickness of from 3,000 to 4,000 feet. I include it with the Ventersdorp System. The thickness of the latter system, which includes boulder beds, coarse conglomerates, volcanic breccias and lavas, is very difficult 1 F. W. Voit, ‘‘Gneiss Formation on the Limpopo ”?: Trans. Geol. Soc. S. Afr, vol. yi (1905). 102 Dr. F. H. Hatch—Geological History ot South Africa. to compute. South of the Rand the Klipriversberg Amygdaloid has a thickness of at least 4,000 feet, and adding this to the thickness of the Elsburg Series, we get a total of 7,000 to 8,000 feet for the thickness of the Ventersdorp System as developed on the Rand. The Potchefstroom System presents difficulties of another kind, owing to the very variable thickness of its lower members, the Black Reef and the Dolomite Series. In the Pretoria and Witwatersrand districts the Black Reef Series is under 100 feet, even sinking to as little as 10 to 20 feet, as has been proved by boreholes on the East Rand*; whereas at Pilgrims’ Rest Mr. Thord-Gray* has recently estimated its thickness at 1,800 feet, while Mr. Sawyer‘ gives it as 1,200 feet at Chunies Poort. The Dolomite Series has been estimated in the Pretoria district at 5,000 feet by Molengraaff,’ although Mr. Kynaston considers it probable that its thickness does not exceed 3,000 feet in that district. In the Makapan Mountains Molengraaff puts it at 4,000 feet, near Godwan at 1,650 feet, in the vicinity of Lydenburg at 2,600 feet, and south of the Witwatersrand at 2,600 feet. Mr. Thord-Gray gives its thickness at Hlandsfontein in the Lydenburg district as 3,000 feet, while Mr. Holmes informs me that from careful measurements he has made in the Marico district, where the series exists in very regular order in the Dwarsberg, he estimates the thickness of the Dolomite at as much as 7,500 feet, the Black Reef Series being very thin there, not more than 75 feet. * Taking the thicknesses given above, it would appear as if where the basal quartzites are largely developed, as in the Lydenburg district, the Dolomite suffers a corresponding diminution, and where the Dolomite is thick the Black Reef is poorly developed. Together, the maximum thickness of the two formations probably does not exceed 8,000 feet. In Griqualand West Messrs. Rogers and Schwarz have found the limestone series, “measured from the quartzites, below which no limestone is seen, to the lowest jaspers or magnetite quartzites of the Griquatown Beds (Pretoria Series),” to have a thickness of 5,000 feet, while the underlying quartzite (Black Reef Series) varies from 200 to 2,000 feet.® The Pretoria Series is estimated by the Transvaal Geological Survey to have a thickness of not less than 10,000 feet.7_ Mr. Holmes has measured this series in the Dwarsberg (Lotteringskop), and 1 F. H. Hatch & G. 8. Corstorphine, ‘‘ The Geology of the Bezuidenhout Valley and the District East of Johannesburg’’: Trans. Geol. Soc. 8. Afr., vol. vii (1904), pp. 97-109. 2 F. H. Hatch, “‘ The Extension of the Witwatersrand Beds eastward under the Dolomite and the Ecca Series of the Southern Transyaal’’: Trans. Geol. Soe. 8. Afr., vol. vii (1904), p. 638. 8 I. Thord-Gray, ‘‘ Notes on the Geology of the Lydenburg Goldfields”: Trans. Geol. Soc. S. Afr., vol. viii (1905), p. 66. 4 A. R. Sawyer, ‘‘ The Geology ot the Transvaal’: North of England Inst. Min. Engineers, 1905. 5 G, A. F. Molengraaff, ‘‘ Geology of the Transvaal’’: Johannesburg, 1904. S A. W. Rogers & E. H. L. Schwarz, ‘* Geology of the Orange River Valley in the Hopetown and Prieska Districts”: Ann. Rep. Geol. Comm. Cape Colony, 1899, 8 p- 80. 7 Transvaal Geol. Surv. Rep., 1903, p. 40. Dr. F. H. Hatch—Geological History of South Africa. 108 informs me that his figures work out to 9,900 feet, which is in very close agreement with the estimate of the Survey. We have, therefore, a maximum aggregate thickness for the three members of the Potchefstroom System of about 18,000 feet. The thickness of the Waterberg Sandstone has not been measured in any place where there is anything approaching a complete section. The lower beds, however, have been carefully examined by Mr. Mellor in the Rhenosterkop area, and were found by him to have a thickness of 3,150 feet.: The Table Mountain Sandstone, which appears to be the Cape representative of the Waterberg,’ is estimated by the Cape Survey to have a thickness of 5,000 feet, and there can be very little doubt that the Waterberg formation is at least as thick. The Bokkeveld Beds, which succeed the Table Mountain Sand- stone at the Cape, are estimated by the Cape Survey at 2,500 feet, and the same thickness is given to the Witteberg Beds, making a total thickness for the Cape System of 10,000 feet. The Bokkeveld and Witteberg Series are, however, absent in the Transvaal. According to Mr. Rogers,’ the Karroo System has a thickness of 18,000 feet, of which 4,900 feet is apportioned to the Dwyka and Heeca Series, 5,000 feet to the Beaufort Beds, and 8,200 feet to the Stormberg, 4,000 feet of the latter being occupied by the volcanic group which forms the summit of the system. Summarising, we have the following maximum thickness for the South African stratified rocks :— Karroo System... ee Aue ist oe Cape System (in which is included the Waterberg formations, as correlative with the Table 18,000 feet. Mountain Sandstone) : a8 Be 10,000 ,, Potchefstroom System ... “ai ... about 18,000 ,, Ventersdorp System 200 300 ... about 8,000 ,, Witwatersrand System ... aa we aaa 19,000 ,, Hxcluding the Karroo Beds, there remain some 55,000 feet of beds (say 10 miles) lying below the base of that system and above the Swaziland Beds, or, in other words, below the Permo-Carboniferous of EKurope. When we take into consideration the gaps represented by four great unconformities, we see that the ‘ geological column’ must necessarily be much greater than this total, since no allowance is made for the losses due to denudation. It probably embraces the period of time covered by the Devonian, Silurian, Ordovician, and Cambrian Systems of the European classification. Unfortunately, no correlation with the European formations is at present possible, on account of the complete absence of fossils in all the South African formations below the Bokkeveld (Devonian) Beds.* But we need not despair of finding organic remains in some 1 Transvaal Geol. Surv. Rep., 1904. 2 F. H. Hatch & G.S. Corstorphine: ‘‘ The Geology of South Africa,’’ p. 309 ; London, 1905. 3 A. W. Rogers: ‘‘ The Geology of Cape Colony,” p. 147; London, 1905. 4 Quite recently some lamellibranch remains have been found by the Cape Survey in the Table Mountain Sandstone, but have not yet been determined. 104 Prof. E. Hull—The Great Pleistocene Lake of Portugal. of these formations, when we remember the patient search that has been necessary in Europe in order to obtain fossil evidence for the age of important formations. Rogers! instances the work done in the north of Devonshire by two generations of geologists before the Morte slates were found to be fossiliferous. We may still hope that some of our more promising shales and limestones will yet yield paleontological evidence which will enable them to be correlated with the classic systems of Europe. (Zo be concluded in our next number.) II].—Tue Puystcan History or tHe Great Prueistoornge LAKE OF PorRTUGAL.’ By Professor Epwarp Hutt, LL.D., F.R.S., F.G.S. RECENT visit to Portugal has given me an opportunity of seeing the geological features of the neighbourhood of Lisbon and the Lower Tagus ; and though of a somewhat cursory nature I venture to bring them before the Society, being supplemented by reference to the investigations of previous observers, and a study of the excellent geological maps which are in the library of this Society. I make no pretension to be an original explorer, but I hope to be able to show that there is a very interesting physical history, not hitherto written so far as I am able to discover, bringing down the account of the changes which have taken place from the Cretaceous period to the Recent, or Quaternary, epoch. In addition to my own observations I have relied for the necessary data for this paper on the geological maps of Portugal,* together with the papers of the late Mr. Daniel Sharpe* and of Mr. Smith °® of Jordan Hill, which sufficiently put us in possession of the materials for an historical sketch of the remarkable physical changes which the Iberian Peninsula has undergone, at least along its western margin, in Tertiary and still more recent times. Geological Formations. The formations bordering the lower banks of the Tagus near Lisbon are arranged by Sharpe in the following order of succession :— Mr. D. Sharpe’s Classification. 1. Upper Tertiary Sands, ete. 2. Almada Beds (Marine). 3. Lower Tertiary Conglomerate. 4, Hippurite Limestone (Cretaceous). ‘Geology of Cape Colony,’’ p. 114; London, 1905. ~ 2 Rend before the Geological Society, ‘December 6th, 1905. 3 «Carta Geologica de ‘Portugal,’ ed. by Carlos Riberio & J. F. N. Delgado (1876) ; ‘*‘ Mapa Geologico de Espaiia y Portugal,” by D. F. de Botella (1879). 4 «On the Geology of Lisbon”: Trans. Geol. Soc. ., ser. 11 (1839), and Q.J.G.8 vol. vi, p. 134 (1850). ‘ ") On the Age of the Tertiary Beds of the Tagus”: Q.J.G.S., vol. iii, p. 410 (184 Prof. E. Hull—The Great Pleistocene Lake of Portugal. 105 In the Zegenda of the Geological Map of Portugal the succession does not materially differ from the above, and is as follows :— Moderno e quaternario (alluvial). mevevario Lacustre superior. Marino (Almada Beds). Lacustre inferior. 2 Superior (Hippurite Limestone). CEI { Inferior. Description. The Upper Tertiary (Lacustre superior) consists of fine white, yellow, and red sands, with thin layers of rolled pebbles, nearly horizontal and 100 feet in thickness, resting on 150 feet of coarse ferruginous sands and gravel; no organic remains have been observed in these beds; but at a locality 15 miles from Verdelha, on the north bank of the Tagus, the hills rising about 200 feet above the sea consist of brown marl and soft rubbly limestone containing Lymnea longiscata (Sow.), and have been traced from Cartaxo to Santarem. These are probably the uppermost beds of the lacustrine series, and overlie the sands and gravels previously described. At Villa Franca a bed of marl occurs 50 feet above the Tagus with Lutraria compressa, and near Villa Nova da Rainha the same shell occurs with Cardium edule, both now living in the estuary of the Tagus near Lisbon; so that, as Sharpe observes, it is evident that this part of the country has been upheaved at least 50 feet within a comparatively recent period.! The occurrence of these shells indicates, as it seems to the writer, a local intrusion of the sea-waters at an early stage of the ‘“‘ Lacustrine ” period. The Almada Beds (Miocene). These beds are so named by Sharpe from the promontory on the south bank of the Tagus, opposite the city of Lisbon, where they are well shown in the sea cliff. They consist of marls and lime- stones rich in marine fossils, and are considered by Smith to be of Older Miocene age. Of the 124 species determined, 20 are new and peculiar, and are figured and described by G. B. Sowerby,? 51 occur in the Older Miocene beds of Bordeaux, 17 in the Falunes of Touraine, 15 in the sub-Apennine beds, 8 in the Eocene of the London and Paris Basins, and 35 are recent. Their claim to be referable to the Miocene stage is thus clearly established. At Lisbon they rest unconformably on the Cretaceous Limestone.® Pliocene Beds not represented. It will be observed that the “Almada Beds” of Miocene age are immediately succeeded by those denoted on the Geological Map of Portugal as ‘‘Lacustre superior,” and by Sharpe called ‘“ Upper Tertiary Sands, etc.” The relative position of these sands to the 1 Sharpe, ibid., p. 138. 2 James Smith, supra cit., pp. 410-423. ° The Almada Beds rest on the sands and gravels called ‘‘ Lacustre inferior,’ but as they are unfossiliferous their geological age is obscure or unknown. 106 Prof. E. Hulli—The Great Pleistocene Lake of Portugal. underlying ‘‘ Almada Beds” in the neighbourhood of Lisbon is very clearly shown in the sections accompanying Mr. Sharpe’s paper; for, while the Almada Beds are inclined at angles varying from 10° to 15°, the Upper Sands are well-nigh horizontal. In addition to this the Almada Beds have been faulted and denuded, and subjected to disturbances which do not affect the Upper Lacustrine Sands. All these phenomena go to indicate absolute disconnection between the two formations, a disconnection which in time would in other districts have been filled up by the Pliocene beds, but which are here altogether absent from their place in the geological series. The cause of this lacuna I hope to be able to explain further on. The Sub- Oceanic Extension of the Tagus. When a few years since I] was endeavouring to determine by the aid of the soundings on the Admiralty Charts the physical features of the land areas now covered by the waters of the Eastern Atlantic, I was enabled to show that the principal rivers of Western Europe, and partly of Africa, were continued across the continental platform to great depths and various distances under the ocean from their present outlets. Amongst these the sub-oceanic Tagus was one of the best developed, and can be well delineated owing to the large number of soundings off the coast of Portugal. The isobathic contours are perfectly clear, as will be seen from the photographic slides, together with those of the Adour in the north of Spain and the Congo on the coast of Africa.’ In reference to the sub-oceanic canon of the Adour, I may mention that Dr. Nansen, who in northern latitudes has studied these physical features, has stated that it is impossible to suppose that it can be anything else than a drowned river valley.* I do not intend to go farther into the question of these submerged valleys, except as they are connected with the geological history of the agus valley. Their existence is clearly due to river erosion, inasmuch as they could not have been formed under the ocean- waters themselves. The question we are here concerned with is the determination of the geological period of their formation. The conditions must have been those of great land elevation affecting the ocean-bed and adjoining lands. That they are not of great geological antiquity is shown by the fact that the rivers with which they were continuous are geologically modern, more modern indeed than the Chalk, and, in this district, than the Miocene, which, as shown above, is a marine deposit. Pliocene Elevation. It is to the Pliocene and post-Pliocene epochs that we must therefore refer that great land-uprise which would be necessary for the erosion 1 These photographic pictures were then exhibited, but have already gee ate in the Trans. Vict. Inst., vols. xxxi and xxxii. * Nansen, “ Bathymetrical Features of the North Polar Seas, etn at P 95 1893-5). Prof. E. Hull—The Great Pleistocene Lake of Portugal. 107 of these river-valleys, and owing to which there was no deposition of strata under the ocean. To this cause I venture to attribute the absence of representatives of the Pliocene formation in Portugal ; as, indeed, is the case with other parts of the Continent and the western areas of the British Isles. From the above considerations it will be seen that between the “Upper Tertiary Sands” of Sharpe (or the “ Lacustre superior” of the Geological Survey) and the marine “Almada Beds” there is no physical connection. As regards periods of formation, they are separated by the whole of the Pliocene and probably post-Pliocene periods, as already stated. It is therefore necessary to revise the classification of the post-Cretaceous series of the authors above quoted, and I therefore venture to substitute for these the following arrangement of the beds. Revised Classification. ( 1. Recent and Quaternary. Alluvia of the valley and estuary of Quaternary the Tagus. { 2. Lacustrine. Marls with Lymnea, sands and gravel. 3. Post-Pliocene and Pliocene. Not represented unless by some land- glacial beds due to elevation. 4, Miocene. Almada Beds, calcareous marls and Renter limestones with marine fossils. y 5. NHocene (?). Untossiliferous sands and gravels (Lacustre inferior) of doubtful age. Cretaceous 6. Upper. Hippurite Limestone. Personal. When observing the sections of strata, along the line of the railway for several miles between Carlaxo and Abrantes, consisting of white, yellow, and red laminated sands, with lines of rolled pebbles, horizontally stratified, and extending to a height of 150 to 200 feet above the river, it became evident that these beds could not have been deposited by the river itself; and I arrived at the conclusion that they must have formed the bed of an extensive lake. I was therefore anxious to ascertain whether my conclusion was borne out by the Geological Survey Map of Portugal. It was therefore with great satisfaction that on consulting the maps I found that these beds were included under the term “ Lacustre superior.” They are specially coloured, and, according to Sharpe, cover an area of “2,000 to 5,000 square miles.”’ On crossing the Tagus at Praia we find the country formed of extensive plains of gravel, from which at Das Vargans and Cunheira the bed-rock of granite emerges and the gravel and sand cease; this limit of the lacustrine beds probably corresponds very nearly with that of the original waters of the lake itself. To this point of the limit of the lake it is. now necessary to direct our attention for a brief space. 1 Supra cit., p. 138. 108 Prof. E. Hull—The Great Pleistocene Lake of Portugal. The Limits of the Pleistocene Lake of Portugal. In dealing with this question I have to be guided by the Geological Map of Portugal, on which is represented the area of the ‘“ Lacustre superior ” beds by a light-yellowish tint. Thus guided, the margin of the lake stretched along the banks of the Tagus from Cartaxo to Abrantes; then turning southwards it stretched to Alvallade, and thence to the Atlantic coast and the mouth of the Tagus. Over this area the lacustrine beds rest directly on the granitic rocks, or on the supposed “ Lower Lacustrine” beds (Lacustre inferior), the Miocene beds being absent; they have therefore no connection with the upper lacustrine deposits with which we are dealing. The margin of these deposits is, according to the map, much indented along the river-valleys flowing towards the west, and showing that they have been considerably denuded during the rising of the land which took place subsequently, and to which is owing the drainage of the lake itself. During the period of depression in which the waters of the lake accumulated, it would appear that the general level of its bed was nearly that of the outer sea, and that ‘the sea-waters gained access occasionally during the earlier stage of its formation, owing to which (as already stated) some marine molluscs gained access. The magnificent harbour of Lisbon doubtless formed a portion of the lake, and the narrow channel by which it is connected with the ocean may be regarded as the unsubmerged portion of the great sub-oceanic canon which carried the waters for about fifty miles beyond its present outlet. On the final uprise of the land to its present level the channel of the river was deepened, and the waters of the lake were drained off; and thus the great river which filled the basin afterwards became the agent by which it was ultimately drained. Such appears to have been the physical changes coming down into recent times which have brought about the present conditions of land and sea in the western part of the Iberian Peninsula. Glacial Conditions in Pliocene Times in Portugal. In connection with the Pliocene elevation here postulated, it is interesting to observe that it was concurrent with extensive glacial conditions in the western portion of the Iberian Peninsula. It has long been known that the glaciers of the Pyrenees, like those of the Alps, extended far beyond their present limits in the Glacial period, but it is not so generally known that Portugal was the seat of extensive glacial conditions. This, however, was the case; and according to the views of Sgr. Delgado, the Director of the Portuguese Geological Survey, than whom there is no higher authority, these conditions commenced with the Pliocene epoch, gradually giving way to one of progressive refrigeration of the climate, accompanied by an invasion of glacial ice descending from the mountain chain of the Serra d’Estrella. This chain, commencing Prof. E. Hull—The Great Pleistocene Lake of Portugal. 109 at Garda, ranges in a south-west direction through the centre of Portugal, attaining a height of 6,539 feet, and was, in all probability, the most important axis of glacial dispersion during the post- Pliocene period. Of the great extent of glacier-ice both to the north of the Serra, where it invaded the affluents of the Mondégo, as well as the regions to the south towards the valley of the Tagus, there can be no doubt since the publication of M. Delgado’s elaborate memoir,! following on that of his late colleague, M. Frederico A. de Vasconcellos,? both beautifully illustrated by photographic plates, recalling all the familiar phenomena of mountainous regions from which the glaciers have disappeared.. According to Delgado there were two glacial stages separated by an interglacial one (‘‘La phase interglaciaire”’), corresponding to those which, in company with some British geologists, I have long held as having occurred in the British Isles. The most important point to be noticed is the occurrence of these glacial phenomena. at an epoch corresponding to that of the elevation of the land and the erosion of the now submerged valley of the Tagus. If there are any geologists who regard this concurrence of events as. accidental I am unable to agree with them. To the mind of myself, and a goodly number of other physicists both in Britain and America,®> the glacial conditions are the direct result of the land elevation, for the simple reason that altitude above the sea-level is the governing factor, though not the only one, in the occurrence of warm and cold temperatures in all parts of the globe, even in equatorial regions. If the surface of Portugal was sufficiently elevated to allow of the erosion of the Tagus out to a distance from the coast of 55 miles, and to a depth of over 7,000 feet from the surface of the ocean,t we have the measure of the elevation of the land at the Glacial period. Adding, therefore, the depth of the submerged canon (7,200 feet) to the present elevation of the Serra d’Hstrella (6,539 feet), we have as the result a mountain 18,759 feet high, a height sufficient, notwithstanding its latitude, to give rise to a system of glacial dispersion and erosion, to some degree, comparable with that of the Alps at the present day. I now feel satisfied that, on observing the forms of the granite masses as they emerged from beneath the lacustrine gravels towards the Portuguese frontier, I was not mistaken in recognising them as ice- worn surfaces. 1 «¢ Note sur l’Existence d’anciens Glaciers dans la Vallée du Mondego,”’ par J. F. Nery Delgado, extr. des Communicadses da Direc. dos Tratalhos Geologicos, tome iii (1895). 2 Tbhid., tome i, p. 189 (1887). 3 See Professor J. W. Spencer on ‘‘ Professor Hull’s Sub-oceanic Terraces, etc.,’” a review, American Geologist, vol. xxxv (March, 1905), 4 Trans. Vict. Inst., vol. xxxi, p. 284, footnote. 110 Prof. J. W. Gregory—Fossil Corals from Egypt, ete. JIJ.—On a Cottecrion or Fosstn Corats rrom Eastern Eeypt, Asu RoasH, AND SINAI. By J. W. Grucory, D.Sc., F.R.S., F.G.S., Professor of Geology, Glasgow University. (PLATES VI ann VII.') (Concluded from the February Number, p. 58.) III. PLEISTOCENE. SYMPHYLLIA, Edwards & Haime, 1848. SYMPHYLLIA ERYTHRACEA (Klunz.), 1879. Tsophyllia erythracea, Klunzinger, 1879: Korallth. roth. Meer., pt. iii, p. 10, pl. i, fig. 10; pl. ix, fig. 9. Symphyllia erythracea, Gregory, 1898, Egypt. Foss. Madreporaria: Grou. Mae., Dec. IV, Vol. VY, p. 242. Distribution.—Recent : Red Sea (Klunzinger). Pleistocene, fossil : ? Jebel Zeit (Gregory, 1898) ; also Old Beach, Camp 7; Wadi Barud, Hastern Egypt. No. J 1789. STYLOPHORA, Schweigger, 1819. 1. SrynopHora ELONGATA (Lamarck), 1816. . Porites elongata, Lamarck, 1816: Hist. nat. Anim. sans Vert., vol. ii, p. 271. Stylophora elongata, Klunzinger, 1879: Korallenth. roth. Meer., pt. ii, p. 64, pl. vii, fig. 14; pl. vii, fig. 19. Six fragments and a slide cut from one of them (No. J 2153), collected by Mr. Barron on the coastal plain between Ras Jemsa and Jebel Zeit, agree in all characters with this species, which is clearly very closely allied to S. pistillata (Esper), the common Red Sea form. Hight worn fragments, J 2186, from the raised beach, east of Jebel Esh, belong to the same species. 2. StrynopHora cf. patmata (Blainville), 1830. Sideropora palmata, Blainville, 1830: Dict. Sci. nat., vol. lx, p. 360. Stylophora palmata, Edwards & Haime, 1850: Ann. Sci. nat., ser. 11, vol. xiii, p. 1038. Distribution. — Recent: Red Sea and Indian Ocean. Fossil, Pleistocene: 380 feet above sea-level,.near Camp 8 in Wadi Shigeli. There are two limestone specimens, which bear surface casts of a Stylophora, which are probably S. palmata, but they are not sufficiently well preserved for certain identification. They were collected by Mr. Barron, 380 feet above the sea, near Camp 7 in Wadi Abu Shigeli. J 1667. CCELORIA, Edwards & Haime, 1848. Ca@LoRIA LAMELLINA (Ehrenberg), 1834. Platygyra lamellina, Ehrenberg, 1834, Beit. Corallenth. roth. Meer.: Abh. k. Akad. Wiss. Berlin ftir 1832, p. 323. Ceeloria lamellina, Edwards & Haime, 1851: Pol. foss. Terr. paleoz., p. 93; 1857, Hist. nat. Cor., vol. ii, p. 416. 1 [By an error of the binder, doth Plates VI and VII appeared in the February Number with the first part of this paper.—Epir. Gzon. Mae. | » Prof. J. W. Gregory—Fossil Corals from Egypt, ete. 111 Celoria ehrenbergiana, Rdwards & Haime, 1849: Ann. Sci. nat., ser. 111, vol. xi, . 296. Paty ati labyrinthica, var. leptochila, Ehrenberg, 1834: op. cit., p. 328. Celoria labyrinthiformis, Haeckel, 1876: Arab. Korall., pl. ii, fig. 4. Celoria forskaliana, Edwards & Haime, 1849: op. cit., p. 296. Celoria forskalana, Edwards & Haime, 1851: op. cit., p. 93; 1857, op. cit., p. 414. Celoria botte, Edwards & Haime, 1849: op. cit., p. 295; 1851, op. cit., p. 93 ; 1857, op. cit., p. 414. Celoria subdentata, Edwards & Haime, 1849: op. cit., p. 296; 1857, op. cit., p. 413. Celoria arabica, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 17, pl. ui, figs. 1, 2, 3, 8; pl. ix, figs. 10a—e. The best specimen in the collection is a large, massive block (J 1578), which I refer to var. triangularis, Klunz., but it is so eroded that the calices are destroyed, and the depth of the calicular furrows gives it some resemblance to var. leptochila, Ehr. Klunzinger renamed the common Red Sea Coeloria C. arabica, though there are several names with prior right, and I have, therefore, adopted the oldest of them. The specimens referable to C. lamellina are :— J 1578, a large specimen of var. triangularis, Klunz.: raised beach, Camp 4, 80 feet above the sea, Wadi Hamrawein, near Qosseir. J 2115, a specimen of var. triangularis, Klunz.: lower raised beach, north of Qosseir. J 2234, a specimen of var. subdentata, Hd. & H.: raised beach, east of Gharib. J 2231, a specimen of var. leptochila (Khr.): raised beach, east of Gharib. K 1630, a specimen of the typical form: raised beach, 80 feet above sea-level, Wadi Gueh, Qosseir. FAVIA, Oken, 1815. 1. Favia topata (Edwards & Haime), 1850. Parastrea lobata, Edwards & Haime, 1850: Ann. Sci. nat., ser. 111, vol. xii, p. 171. Favia lobata, Edwards & Haime, 1857: Hist. nat. Cor., vol. ii, p. 434, pl. p 8, fig. 3. Favia lobata, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 31, pl. iii, fig. 9 ; pl. x, fig. 8. Distribution. — Recent: Red Sea. Fossil, Pleistocene: raised beach, Camp 4, Wadi Hamrawein, near Qosseir, K 1633; lower raised beach, north of Qosseir, J 2148. 2. FavIA EHRENBERGI, Klunzinger, 1879, var. sutcata, Klunz. Korallenth. roth. Meer., pt. iii, p. 29, pl. iii, figs. 5, 8. Distribution. — Recent: Red Sea. Fossil, Pleistocene: raised beach, Camp 6, northern Wadi Queh, K 1577. Some corallites of the Havia ehrenbergi type in a corallum of Goniastrea pectinata, J 1819 (see Pl. VII, Fig. 14). GONIASTRAIA, Edwards & Haime, 1848. 1. GoNIASTRHA RETIFORMIS (Lamarck, 1816). Astrea retiformis, Lamarck, 1816: Anim. sans Vert., vol. ii, p. 265. Goniastrea retiformis, Edwards & Haime, 1850: Ann. Sci. nat., ser. 111, vol. xii, p. 161. 112) Prof. J. W. Gregory—Fossil Corals from Egypt, ete. * ‘opettidasa tee eaiaae Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 36, pl. lv, Hg. o. Distribution. — Recent: Red Sea, Indian and Pacific Oceans. Fossil, Egypt: raised beach, 50 feet above sea-level, Jemsa, J 2032; lower raised beach, north of Qosseir, J 2118; raised beach, east of Gharib, J 2282. 2. GONIASTRHA PECTINATA (Ehrenberg), 1854. Astrea pectinata, Ehrenberg, 1834, Beitr. Corallenth: Abh. k. Akad. Wiss. Berlin fiir 1832, p. 320. Goniastrea pectinata, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 34, pl. iv, fig. 6. Distribution. — Recent: Red Sea. Fossil, Pleistocene: lower raised beach on coast plain, north of Qosseir, J 2119; raised 50 feet beach, Jemsa, south of Jebel Zeit, J 1819. The specimen (J 1819) is of interest, as it shows one of these cases in which some of the corallites of the same specimen would, if found dissociated, be assigned to distinct genera. Part of the surface is shown on Pl. VII, Fig. 14. The narrow walled corallites on the left side of the figure agree with G. pectinata; but those in which the calices are separated by wide valleys, so that even the coste of the adjacent corallites do not unite, have the form of Favit ehrenbergi. Such occurrences show that the plasticity of the corals is such that occasional abnormal polypes may suddenly acquire the characters of another genus. 3. GontastRHA FAVUS (Forskal), 1775. Madrepora favus, Forskal, 1775: Descr. Anim. Itin. Orient, p. 132. Goniastrea favus, Klunzinger, 1879:, Korallenth. roth. Meer., pt. iii, p. 35, pl. iv, fig. 4; pl. x, fig. 7. Distribution.— Recent : Red Sea, Indian Ocean. Fossil, Pleistocene : raised beach, 50 feet above sea-level, Jemsa, J 2052. SOLENASTRAIA, Edwards & Haime, 1848. 1. SozenastR#a cHALcIDIcuM (Forskal),1775. (Pl. VII, Fig. 12.) Madrepora chaleidicum, Forskal, 1775: Descr. Anim. Itin. Orient., p. 136. Cyphastrea chaleidicum, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 53, len eso ep la eno ll. Distribution. — Recent: Red Sea. Fossil, Pleistocene: raised beaches near Qosseir. Figures.—Pl. VII, Fig. 12, part of the surface of a worn corallum of J 2140, from near Qosseir, by 2 diam. J 1683, a very altered specimen, but judging by the cellular exotheca and rudimentary columella it is S§. chalcidicum rather than S. serailia, the alternative identification : Camp 4, Wadi Hamrawein, north-west of Qosseir, Eastern Egypt. H 1658): Camp 4, Wadi Hamrawein. H 16388e¢, a very weathered specimen, bored by Lithodomi: Camp 4, Wadi Hamrawein. H 1688/: Camp 4, Wadi Hamrawein. Prof: J. W. Gregory—Fossil Corals from Egypt, etc. 118 J 2122, 2188, two young coralla, one 27 mm. diam.: lower raised beach, north of Qosseir. J 2136, a well-preserved specimen: lower raised beach, north of Qosseir. J 2140, two specimens with dense walls: lower raised beach, north of Qosseir. J 2149: lower raised beach, north of Qosseir. 1623, a much altered specimen, which, however, retains some of the original surface, showing the extent of projection of the calicinal edges: raised beach, Camp 4, Wadi Hamrawein, near Qosseir. 1628, a well-preserved specimen: 80 feet above sea-level, Wadi Queh, near Qosseir. 2. SoLENASTRHA SERAILIA (Forskal), 1775. Madrepora serailia, Forskal, 1775: Descr. Anim. Itin. Orient., p. 135. Cyphastrea serailia, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 52, pl. v, fig. 4; pl. x, fig. 12. Solenastrea forskalana, Edwards & Haime, 1850: Ann. Sci. nat., ser. 111, vol. xii, p- 123; 1857, Hist. nat. Cor., vol. ui, p. 497. : Distribution. — Recent: Red Sea. Fossil, Pleistocene: raised beach, east of Jebel Hsh, J 2177. This specimen has the more compact exotheca and the equality of the septa of the first and second cycles, which are two of the chief distinctions of this species as compared with S. chalcidicum (Forsk.). 3. ?SoLENASTR#A SAviGNyt (Hd. & H.), 1850. Cyphastrea savignyi, Edwards & Haime, 1850: Ann. Sci. nat., ser. m1, vol. xii, p. 115. Buea kes, ee Klunzinger, 1879: Korallenth. roth. Meer., pt. ii, p. 51, pl. v, fig. 7. This specimen (J 1826) is a large block with long, thin corallites, about 24-3 mm. in diameter. It agrees with this species by its compact endotheca, and the marked inequality of the primary and secondary septa. But the specimen has been so altered that its identification is not free from doubt: ORBICELLA, Dana, 1848. 1. ORBICELLA ForsKALI (Edwards & Haime), 1849. Astrea forskaliana, Edwards & Haime, 1849, Mon. Astr.: Ann. Sci. nat., Zool., ser. 111, vol. xii, p. 100. For Egyptian references and synonyms, see Gregory, 1898, Kgypt. Foss. Madrep., Grou. Mac., Dec. IV, Vol. V, p. 242. Distribution. Recent: Red Sea. Fossil, Pleistocene: low-level and high-level raised reefs, near Jebel Zeit; also near Qosseir, Wadi Abu Shigeli, and Wadi Barud. H 1683c; this specimen is much weathered, and has no trace of the surface, but the available characters are the same as those of J 2188: Camp 4, Wadi Hamrawein, near Qosseir. J 1669, a specimen with the calices 6-8 mm. in diam. ; the corallites are circular and not elliptical as in O. mammillosa: raised beach, 80 feet above sea-level, Wadi Abu Shigeli. DECADE V.—VOL. III.—NO. III. 8 114 Prof. J. W. Gregory—Fossil Corals from Eyypt, ete. J 1789, a block with corallites 7 mm. in diam.: old beach, Camp 7, Wadi Barud. J 2188, a small specimen but with well-preserved characters: lower raised beach, north of Qosseir. 2. ORBICELLA MAMMILLOSA, Klunzinger, 1879. Korallenth. roth. Meer., pt. iii, p. 49, pl. v, fig. 5; pl. x, fig. 10. Distribution.—Recent : Red Sea. Fossil, Pleistocene: Egypt and Gulf of Tadjura (Faurot), lower raised beach, north of Qosseir, No. J 2145. This specimen is worn and is fragmentary ; it has three cycles of septa, a large columella, and some of the corallites are oval in section. In a previous paper (Grot. Maa., 1898, p. 242) I included this Orbicella in O. forskali, and I still think that it may well be merged in that species. But as it is necessary to contrast these fossils as closely as possible with the recent Red Sea fauna, I am, for this purpose, recording the specimen under Klunzinger’s name. The following species is provisionally accepted for the same reason. 3. ORBICELLA LAXA, Klunzinger, 1879. Op. cit., pt. iii, p. 49, pl. v, fig. 3; pl. x, fig. 9. : Distribution.n—Recent: Red Sea. Fossil, Pleistocene: Egypt. H 1635, a large block with thin walls, thickened by some secondary calcification: Camp 4, Wadi Hamrawein, near Qosseir. H 16338d, a specimen with corallites varying from 8 to 10mm. in diam.: Camp 4, Wadi Hamrawein, near Qosseir. K 1663, a specimen with somewhat smaller calices, 7mm. in diam. The corallites are close, and have very little exotheca; the walls are thin, and the septa number 27 to 80. None of the surface is shown. ‘This is the coral which differs most from the central type of O. laxa, but I do not see any adequate reason for excluding it from that species: 380 feet above sea-level, near Camp 7, Wadi Shigeli. ECHINOPORA, Lamarck, 1816. 1. Ecoutnopora rruricunosa (Ehrenberg), 1834. Stephanocora hemprichii, forma fruticulosa, Ehrenberg, 1834, Beitr. Korallenth. : Abh. k. Akad. Wiss. Berlin fiir 1832, p. 301. Echinopora fruticulosa, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 55, pl. vi, fig. 4. Distribution. — Recent: Red Sea. Fossil, Pleistocene: Egypt, 380 feet above sea-level, near Camp 7, Wadi Shigeli, K 1660. This specimen is the irregular nodular base of a coral with calices 5-5:5 mm. in diameter, so they are somewhat smaller than in the recent corals, and the paliform processes are perhaps less distinct. It is, moreover, not raised in definite branches, but would probably have developed thus had it grown larger. In other respects it appears to be the same as the recent forms. K 1665, from the same locality, is a fragment of Hchinopora, but is specifically indeterminable. Prof. J. W. Gregory-—Fossil Corals from Egypt, ete. 116 GALAXHA, Oken, 1815. GALAXEA FASCICULARIS (Linnzeus), 1767. Madrepora fascicularis, Linneeus, 1767: Syst. Nat., 12th ed., vol. i, pt. 2, p. 1278. Madrepora fascicularis, Ellis & Solander, 1786: Nat. Hist. Zooph., p. 151, pl. xxx. Galaxea fascicularis, Oken, 1815: Lehrb. Naturgesch., Th. iii, Zool., Abt. 1, p. 73. Galaxea fascicularis, Klunzinger, 1879: Korallenth. roth. Meer., pt. ii, p. 78. Distribution. — Recent: Red Sea. Fossil, Pleistocene: raised beach, 80 feet above sea-level, Wadi Queh, near Qosseir, K 1629 ; Camp 6, Wadi Queh, K 1631. These are two excellent specimens. The septa of the primary and secondary cycles are subequal, and the corallites are from 65 by 9mm. or 6:5 by 10mm. in diameter, and they are not gyrose or so compressed as in G. irregularis, Hd. & H. LEPTASTRAA, Edwards & Haime, 1848. LEpPTASTRHA EHRENBERGANA, Edwards & Haime, 1850. Ann. Sci. nat., ser. 111, vol. xii, p. 120; and Hist. nat. Cor., vol. ii (1857), p. 494, pl. v7, fig. 4. Distribution.—Recent: Red Sea. Fossil, Pleistocene: the raised beach between Jebel Mellaha and Jebel Zeit, J 2160; raised beach, 80 feet above sea-level, Wadi Queh, K 1586. This species has polygonal calices, a well-developed papillary columella, and 24 to 30 septa. In No. J 2160 the calices are 4—7 mm. in diameter. PRIONASTRAMA. 1. PrionastR#A PEeNTAGONA (Hsper), 1796. Madrepora pentagona, Esper, 1795: ‘ Pflanzenth.’ Forsetz., p. 23, pl. xxxix. Prionastrea pentagona, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 41, pl. iv, fig. 11; pl. x, figs. 6, a, 5. DistributionRecent : Red Sea, Egypt. Fossil, Pleistocene : lower raised beach, north of Qosseir, J 2142 and J 2150. 2. PRIONASTRHA TESSERIFERA, Hhrenberg, 1834. Astrea tesserifera, Ehrenberg, 1834, Beitr. Corallenth.: Abh.k. Akad. Wiss. Berlin fiir 1832, p. 321. Prionastrea tesserifera, Kdwards & Haime, 1851: Pol. Terr. paleoz., p. 102. Prionastrea tesserifera, Klunzinger, 1897: Korallenth. roth. Meer., pt. iii, p. 37, pl. iv, fig. 9. Distribution.— Recent: Red Sea. Pleistocene: Sinai, north end of the Quarantine Enclosure, Hl Tor, L 4198. Egypt, raised beach east of Jebel Hsh, J 2177 (two specimens). 3. PrionastrRmA vaAstA, Klunzinger, 1879. Korallenth. roth. Meer., pt. iii, p. 38, pl. iv, figs. 8, 12; pl. x, figs. 4, a, . Distribution—Recent: Red Sea. Fossil, Pleistocene: Egypt, raised beach, east of Gharib, J 2226. Klunzinger has founded this species, which he admits as a very near ally of Prionastrea tesserifera, owing to the greater size of its calices; in P. tesserifera he records them as from 10 to 12 mm. wide and from 10 to 15mm. long, while those of P. vasta he 116 Prof. J. W. Gregory—Fossil Corals from Egypt, ete. records as 10-15 mm. wide and 10-20mm. long; but in his own photograph of P. tesserifera one of the calices is 20 mm. long, and they vary so much in different parts of the colony that P. vasta seems to me only a variety of P. tesserifera with large corallites. But for the sake of precise comparison between the recent and fossil faunas the species may be provisionally accepted. SIDERASTRAMA, Blainville, 1830. 1. SrmpERAsTR#A saAvienyi, Edwards & Haime, 1850. Siderastrea savignyana, Edwards & Haime, 1850: Ann. Sci. nat., ser. m1, vol. xii, Siderastrea savignyana, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 77. Astrea savignyana, Edwards & Haime, 1857: Hist. nat. Cor., vol. ii, p. 508. Distribution. — Recent: Red Sea. Fossil, Pleistocene: Egypt (fide Edwards & Haime) ; also at raised beach, east of Jebel Esh, J 2172-2190. 2. SIDERASTRHA LILACEA, Klunzinger, 1879. Korallenth. roth. Meer., pt. ili, p. 77, pl. ix, fig. 6; pl. x, figs. 16, a, 0. Distribution.—Recent : Egypt, near Qosseir (Klunzinger). Fossil, Pleistocene: lower raised beach, north of Qosseir, J 2122-21388 ; raised beach, east of Jebel Esh, J 2186. : The specimens, Nos. J 2122-2188, include three nodular coralla, of which the two more perfect ones are 56 by 42 mm. in diameter and 25 mm. high, and 29 by 27 mm. in diameter and 18-5 mm. high. FUNGIA, Lamarck, 1801. I have previously called attention to the variability of the Fungi found in the Pleistocene deposits of Egypt.'| Klunzinger accepts four previously described species as found in the Red Sea, and founded three more. He divided them primarily according to the septal teeth, and his secondary division is based on the circular or elliptical form of the corallum. The specimens included in the present collection do not seem to me to agree with Klunzinger’s scheme, as they represent a union of characters. But accepting Klunzinger’s arrangement for the sake of convenience, the Fungias in this collection can be named as follows :— 1. Funera patetta (Ellis & Solander), 1786. Madrepora patella, Ellis & Solander, 1786: Nat. Hist. Zooph., pl. xxviii, figs. 1-4. Fungia patellaris, Lamarck, 1801: Syst. Anim. sans Vert., p. 370. Fungia patella, Klunzinger, 1879: Korallenth. roth. Meer., pt. iii, p. 61, pl. vii, fig. 4; pl. viii, fig. 2. Distribution. — Recent. Fossil, Pleistocene: Egypt, R 13808, Brit. Mus. (Gregory, op. cit.), Sinai, Lower Terrace, south of Hedemia Bay, L 5498. 2. Funera vauipa, Verrill. (Pl. VII, Fig. 13.) Bull. Mus. Comp. Zool., No. 1, p. 51. Distribution Recent: Indian Ocean (Zanzibar). Fossil, Pleisto- cene: Egypt, Wadi Queh; Sinai, Lower Terrace, south of Hedemia Bay. 1 Grou. Mac., Dec. IV, Vol. V (1898S), p. 244. Prof. J. W. Gregory—Fossil Oorals from Egypt, etc. 117 Figures.—Pl. VII, Fig. 18, part of a young corallum from the side, nat. size. K 1560, a set of five specimens ranging from 20 by 21°5 mm. in diameter and 5:5 mm. thick to 60 by 58 mm. in diameter and 11mm. thick. One specimen figured on PI. VII, Fig. 13, retains the anthoagathus: raised beach, Camp 6, Northern Wadi Queh. | K 1589, one well-preserved specimen from the Wadi Queh. L 3498, two specimens, the larger of which is 73 by 67:5 mm. in diameter, and about 11 mm. thick: Sinai, Lower Terrace, south of Hedemia Bay. L 3498, three smaller specimens, of which the largest is 57 by 525mm. in diameter and llmm. high, and its coste resembles F. placunaria, Klunz.: same locality. PORITES, Edwards & Haime, 1860. 1. Portres sonipa (Forskal), 1775. Madrepora solida, Forskal, 1775: Descr. Anim. Itin. Orient., p. 131. Porites solida, Klunzinger, 1879: Korallenth. roth. Meer., pt. ii, p. 42, pl. vi, fig. 14; pl. v, fig. 21. Distribution. —Recent: Red Sea. Fossil, Pleistocene: Egypt, lower raised beach, north of Qosseir, Nos. J 2116 and J 2154. These specimens closely resemble P. lutea, Hdwards & Haime,' but their pali are less distinct, and so I record them under Klunzinger’s name. The depth of the calices cannot be determined in these specimens. 2. Portres nopirera, Klunzinger, 1879. Korallenth. roth. Meer., pt. ii, p. 41, pl. vi, fig. 13; pl. v, fig. 17. Distribution. — Recent: Red Sea. Fossil, Pleistocene: Egypt, raised beach, 80 feet above sea-level, Camp 8, Wadi Abu Shigeli, Coast Plain, north of Qosseir. This specimen is 70mm. high, and above the base the transverse section is elliptical, being 47mm. wide by 28mm.thick. The corallum divides above into short, thick branches. The walls are very thin and trabecular ; the pali are fairly distinct, but the columella is not very apparent; but these structures are not well defined in the irregularly trabecular skeleton of this genus. MONTIPORA, Quoy & Gaimard, 1833. MonrIpora sp. No. J 1826, old beach, Camp 17, Wadi Barud. The collection made by Mr. Barron from this locality includes a worn fragment of a Montipora. But it is too imperfect for determination as to its position in a genus, which, according to Mr. Bernard’s Catalogue, includes 140 recent species. The collection includes some indeterminable specimens as follows : K 1656, cast probably not a coral: raised beach, 300 feet high, Wadi Hamrawein. 1 Edwards & Haime: Hist. nat. Cor., vol. ili, p. 180. 118 Cosmo Johns—Allotropie Forms of Silica. K 1682, cast of a Lithodomus: raised beach, No. 1, north of Qosseir. H 1633a, ? Favia: Camp 4, Hamrawein, near Qosseir. K 1640, (a) Prionastreeoid, indet., (b) Acanthastrea sp., (c) indet. : raised beach, No. 1, 520 feet high, north of Qosseir. K 1664, an Orbicelloid: raised beach, 380 feet above sea-level, Wadi Shigeli. H i776, ? Mussa sp.: Abu Sha’ar Plateau. H 1866a, ? Orbicella: Wadi Belih. J 1826, Acanthastrea sp.: old beach, Camp 17, Wadi Barud. DESCRIPTION OF PLATES. Puate VI. Fie. 1.—Smilotrochus sp. Abu Roash. No. 3795. a, seen from the side; 3, out- line as seen from above. Nat. size. », 2.—Favia humei, n.sp. Miocene: Wadi Belih, Abu Sha’ar. No. H 1780. Part of surface of the corallum. x 14 diam. », 938.—Orbicella mellahica, n.sp. Miocene: west flank of Jebel Mellaha. Part of the surface of H1862. x 14 diam. », 4.—Thesame. Some corallites of 18184. x 2 diam. », 9.—Orbicella schweinfurthi (Felix). Miocene: west flank of Jebel Mellaha. Part of the surface of H 1862 (duplicate). Nat. size. », 6.—0O. defrancei (Kdwards & Haime). Miocene: west flank of Jebel Mallaha. H1862. , 8.—Leptastrea barroni, u.sp. Miocene: surface of Abu Sha’ar Plateau. H 1864. a, part of surface ; 6, another part of surface of same specimen ; e, part of internal section. x 2 diam. Prats VII. Fic. 9.—Stylocenia tuberculata, u.sp. Miocene: Wadi Belik. H1814. a, the coral, seen from side ; nat. size. 6, part of the surface; x 2 diam. »» 10.—Prionastrea lyonsi, n.sp. Miocene: Wadi Belih. H1814a. a, part of worn surface ; 6, part of transverse section. Nat. size. », 11.—Solenastrea elliptica, u.sp. Miocene: Abu Sha’ar. H1818a. a, part of the surface; x 2diam. 4, part of a transyerse section; x 4 diam. 5, 12.—Solenastrea chaleidicum (Forsk.). Pleistocene: raised beach near Qosseir. J 2140. Part of the surface of a worn corallum. x 2 diam. 3, 13.—Fungia valida, Verrill. Pleistocene: Wadi Queh. K1560. Corallum from side. Nat. size. 9, 14.—Goniastrea pectinata (Ehr.). Pleistocene: Jemsa, south of Jebel Zeit. J 1819. Part of the surface of the corallum. Nat. size. IV.—Auorropic Forms or SinicA AND THEIR SIGNIFICANCE AS ConstITUENTS oF IGnNErous Rooks. By Cosmo Jouns, M.I.Mech.E., F.G.S. HAT silica appears as a constituent mineral of igneous rocks. in two distinct phases, viz. quartz and tridymite, has been known for some time. The writer is not aware that any explanation has been offered which would indicate the conditions determining the appearance of one or the other in a cooling fused rock-mass. He now proposes to describe certain experiments made with a view to explain why it is that though the free silica generally appears as quartz, yet occasionally, as in certain trachytes, it crystallizes out as tridymite. Cosmo Sohns—Allotropic Forms of Silica. 119 He was also desirous of clearing up, if possible, the difficulty caused by the conflicting values given to the fusion-point of silica by different investigators. Joly,’ using the meldometer, found quartz to fuse at 1200° C., and, with prolonged heating, even at much lower temperatures. Boudouard,? in the course of his observations on calcic and alumino-calcic silicates, used Seger cones and determined the fusion-point of silica to be 1830° C. Other experimenters have given values varying from 1450° to 1550° C. It is very evident that the differences are too great to be explained by suggesting experimental errors as the cause. Advantage was taken of the fact that a regenerative gas furnace, whose temperature could be regulated and only limited theoretically by the dissociation point of carbon dioxide, was available to make a series of experiments with quartz sand of a high degree of purity. After its specific gravity had been determined, a quantity was introduced into the furnace, rapidly heated to 1500° C., and maintained at that temperature for 48 hours. When withdrawn the material was quite pulverent, and did not show the slightest signs of fusion. It had, however, incrgased in volume and become milk-white in appearance. Selecting the hottest part of the furnace, where the temperature was determined to be above 1800° C., another portion of similar sand was introduced and withdrawn after 30 minutes exposure to that high temperature. On examination the surface of the mass was found to be fused to a depth of 7 or 8mm., but the remainder was in the same pulverent state as that found after the first experiment. Both experiments were repeated, but it was found that quartz sand could only be fused with great difficulty, and only by selecting the hottest part of the furnace. Yet at the same time the temperature of the furnace was such that steel was being maintained in a fluid state with ease. It would seem that Boudouard’s determination is confirmed, and the fusion-point of silica lies above 1800° C. Reference has been made to the fact that the unfused sand had increased in volume during both experiments. This was confirmed when the specific gravity was determined, for the results were as follows :-— Original quartz sand... oa Hob 2°645 sp. gr. After prolonged exposure to 1500° C. ... 206 PERE) 7 oo The specific gravity of the original quartz sand is that of a very pure quartz, and this only confirms the analysis, which showed it to be practically pure silica. The specific gravity of the altered and unfused mass is the average of tridymite. The quartz had, in fact, been transformed into another phase, and later experiments indicated the transformation point to be about 13800°C. It is hoped to make further experiments and determine the point more accurately. It becomes apparent that silica may exist in two solid phases, viz. quartz and tridymite. Also that the former is only stable 1 Rep. Brit. Assoc., 1900, p. 730. * Journ. I. and 8. Inst., vol. i (1905), p. 350. 120 EF. Ht. L. Schwarz—The Thickness of the 1Ice-Cap. below 1300°, and, from Joly’s experiments, fuses at 1200° or even lower. But tridymite is stable below 1800°, and only fuses when that temperature is exceeded. Those familiar with the phase rule will remember instances of a substance having two solid phases each with a different fusion-point. It should also be noted that it was by rapidly heating the quartz up to and beyond the transformation point that the higher fusion-point was realized. The vapour pressure would have some effect in modifying the temperature of fusion of these two phases of silica, and though, owing to the absence of data, this could not be profitably discussed here, yet it is a factor that should be considered when dealing with a cooling fused rock-mass. The significance of the possibility of silica appearing in either of its two solid phases cannot be overlooked owing to its obvious bearing on the question of the thermal conditions attending the consolidation of the igneous rocks. Treating the cooling mass as a case of reciprocal solution, it would appear that the temperature at which silica may be thrown out of solution is a critical point of some importance. If it happens to be above 1500°C., and neglecting for the present the effect of vapour pressure, then the silica would appear in the form of tridymite. If the temperature of the mass happened to be below 1300°C. when silica was thrown out of solution, then quartz would appear. Quartz is generally one of the later minerals to appear in a cooling rock-mass, therefore its predominance in igneous rocks as a phase of silica is not surprising. The comparative rarity of the tridymite phase would also be explained. If the correctness of the writer’s con- clusions be admitted, then we are able to fix within moderate limits the temperature of certain critical points in the cooling curves of the igneous rocks. There is, of course, just a possibility that tridymite is really metastable below the transformation point, but that it requires a long period of time before passing into the more stable form. In that case the geological age of the tridymite-bearing rocks becomes a factor of some importance. V.—Txe Tuickness or THE Ice-Cap IN THE VARIOUS GLACIAL PERIODS. By Ernst H. L. Scuwarz, A.R.C.S., F.G.S., Rhodes University College, Grahamstown, South Africa. N estimating the maximum load which pressed upon the northern type of Glacial (Dwyka) Conglomerate in Prieska, Cape Colony, I assumed that the calculations of Sir Wyville Thomson and Bernacci were correct, and that the greatest column of ice that could exist on the earth’s surface was from 1,400 to 1,600 feet high." This limit, however, is by no means accepted by European glacialists, who, though they do not go as far as Dr. Croll in assuming 1 «An Unrecognized Agent in the Deformation of Rocks’’: Trans. §. African Phil. Soc., vol. xiv-(1903), p. 400. E. H. L. Schwarz—The Thickness of the Ice-Cap. 121 thicknesses of 120,000 feet, yet see no reason why there could not have been ice-sheets 5,000 feet thick. The publication of Captain Scott’s narrative of the voyage of the “ Discovery ” has given us certain definite data from the Antarctic which enable the case for the 1,600 feet maximum to be put with more confidence, and I will endeavour in the present paper to state the main lines of the argument. The question is of importance not only to us in South Africa with our two Paleozoic ice-ages, but to all geologists, as it affects the problem of the earth’s equilibrium. To give a recent example, Professor Penck, in describing the Bodensee, discusses whether the weight of ice pouring down from the Alps in a sheet 3,600 feet thick may not have had some effect in producing a sinking in the earth’s crust.’ To begin with, it is necessary to enquire into the thickness of the ice-sheet at the present day, and in no case where there has been direct measurement has the ice been found to exist in sheets surpassing the 1,600 feet limit. The estimates of the thickness of the Greenland ice-cap rest on assumptions which it is impossible to prove or disprove, but if they are examined closely they will be found to be as favourable to the lesser limit as to the greater one of 6,000 feet. Dr. Nansen’s argument is that the coastline of Greenland is very like that of Scandinavia, and therefore it is permissible to assume that the internal relief of the island continent is the same as that of Norway and Sweden; if the latter were covered with an ice-sheet up to the tops of the mountains the valleys would be filled with ice to depths of 6,000 to 7,000 feet; consequently, in Greenland, allowing for the land surface being somewhat higher than in Scandinavia, the valleys would have accumulations of ice 5,000 to 6,000 feet thick. As confirmatory evidence Dr. Nansen quotes instances of the enormous erosion which has gone on along the coast of Greenland, which he states was produced by glaciers excavating their valleys while filled with ice and giving at the foot pressures of not less than 160 atmospheres.” Von Drygalski, as the result of two expeditions to Greenland, has given elaborate measurements of the glaciers that now end in the sea, and concludes that an iceberg rises higher than the glacier front from which it has calved only when it turns over on its side ;° as the glacier front, where it is floating, rarely rises to 300 feet, icebergs of more than 300 feet high must be ones that have turned over, and are consequently of no use in measuring the height of the original ice-sheet from which they have issued. If we take Steenstrup’s figures for the proportion of the parts of an iceberg above and below water, namely, 1: 7:4 to 1:82, a height of 300 feet would make an iceberg have a base over 2,000 feet deep. Von Drygalski, however, found that soundiags off the edge of 1 Vortriige d. Vereins z. Verbr. Naturwiss. Kennt., xlii (Vienna, 1902), Heft 6, rds JUL, 2 “« The First Crossing of Greenland,’’ Appendix, p. 472; London, 1890, ** Gronland Expedition,” p. 387 ; Berlin, 1897. ** Meddeleser om Gronland,’’ p. 97; Copenhagen, 1879. 122) EF. A. L. Schwarz—The Thickness of the Ice-Cap. floating glaciers gave only a depth of four times the height of the glacier front, and a 300 feet iceberg would therefore be 1,500 feet thick in all. Scott says the same thing for the Antarctic, where 120 to 150 feet icebergs do not touch bottom in more than 100 to 120 fathoms of water, giving a proportion of something like 1 : 5 for the portions above and below water.! The discrepancy between the estimated and observed proportions is explained by the experiment performed by the ‘“ Challenger” in firing cannon-balls into an ice- berg: while some layers reacted like solid rock, others were so soft that the balls imbedded themselves, proving that a large proportion of the berg was soft, spongy, and filled with air, thus making it buoyant. Scott found that the Great Barrier ice rose at one point to 240 feet above sea-level, but as some portions sank to nearly sea-level, these greater elevations may safely be put down to pressure ridges; the average height was under 200 feet. The height of the ice-column in the Great Barrier may give too low a figure for the mass of ice as it leaves the land, whereas that of the Greenland glaciers, coming steeply off the land, probably gives too high a one. The point I wish to emphasize is that the whole resources of the Greenland ice-cap and the great snow-fields of the Antarctic, can only produce a sheet of ice in the valleys or places of greatest accumulation of heights that are near the estimated possible maximum, namely, 1,600 feet. These estimations depend on the ice being 0° C. at the junction of the sheet with the earth, and doubt has been thrown on this. Ice only becomes colder than its melting-point by reason of radiation of heat into space, and where this is stopped by great thickness of ice —ice being a bad conductor of heat—the temperature of the ice will rise from any degree below zero at the surface to 0° C., where the heating effect due to pressure comes into play. V. Drygalski has given a large series of observations bearing on this question, and the same rise of temperature is observed as in the case of the earth’s crust, only on a more exaggerated scale. The following are a few extracts, temperatures in degrees Centigrade (Celsius in the original) :— ? ‘TEMPERATURE IN THE IcE on THE GREAT Karasak GLACIER, 175m. above sea-level. Gin. (‘15 m.) 17-5 ft. (5-4m.) 28-9 ft. (8-9 m.) 80th October, 1892 ae — 13:7 es = 3-7 ; — 2°9 19th November, 1892... —13°7 && — 10:1 es —7:2 29th November, 1892 ... — 19:2 sate — 55 wag — 5:2 2nd February, 1893... — 32°9 oe — 61 — 5:0 14th April, 1893 ose — 15:0 — 9:0 —9°2 The last figure in the third column is the greatest cold found at this depth; it was taken on April 14th, and denotes the lag in the temperature of the interior of the ice-sheet when the surface was. becoming warmer. These figures demonstrate sufficiently clearly 1 “Voyage of the ‘ Discoyery,’”’ p. 410; London, 1905. * “ Greenland Expedition,’’ pp. 451-2. Ei. H. L. Schwarz—The Thickness of the Ice-Cap. 128 that the lowering of the melting-point of ice due to pressure is not materially affected by the intense cold at the surface, and that therefore we may take the physicists’ estimate of the maximum thickness as approximately correct. Scott found the Antarctic ice-cap to be flat on the surface of the land with an edge of rock which, from the sea, appeared to consist of lofty mountains, but the highest points of these sank below the horizon directly the level of the ice-cap was reached. Peary and Nansen have found the same thing in Greenland. The tops of the mountains look as if they once were part of a peneplain, but Nansen maintains that it is not likely that a great land-mass like Greenland should be all on a level beneath the ice. In his later researches, however, Nansen has demonstrated the existence of a vast sub- marine plateau in the Arctic Ocean, and if the plateau here rose above the sea by block-uplift it would be covered by ice and protected from denudation by ice. Douglas Freshfield, in his address to the British Association at Cambridge, stated that it is at the face of the glacier that denudation begins, and the configuration of the coastline in Greenland and in the Antarctic regions bears this out; the valleys go but a short way inland, and are ended abruptly. If, then, there is some reason to suppose that the polar ice-caps lie on level land, the argument for estimating the thickness of ice above the limit which physicists say is the maximum is shown to be of doubtful value. The only way by which a sheet of ice over the 1,600 feet limit can exist is when the surface of the ground on which it rests is below the temperature of the melting-point of ice, and to obtain such a condition of things there must be a cause of abstraction of heat from within the earth, as the ice-sheet forms a blanket to protect the surface of the ground from radiation from above. The heat of the earth’s interior is always creeping outwards, and instead of abstracting heat from the ice it is the ice that is abstracting heat from the earth. Not only is this true for the existing ice-caps, but it must have been true for the ice in the Glacial periods of the northern hemisphere and the Paleozoic ice-ages of the southern, and I cannot, therefore, see how it is possible, in the light of physical experiment, supplemented by actual observation, to obtain the great thickness of ice that glacialists ordinarily call in to explain. the phenomena which they have described. Finally, there is one observation of Commander Scott’s* which perhaps explains the enormous apparent thickness of glacier ice in past ages as seen in the evidence afforded by ice-scorings on the sides. of the valleys. In the Ferrar glacier the ice had once been from. 3,000 to 4,000 feet higher than it is at present. There is also reason to suppose that the climate was milder at the period of maximum glaciation, because it is physically impossible for cold air to contain much moisture and consequently to feed the glacier streams. With a milder climate the ice must have melted more easily, and yet even. 1 ¢¢ Voyage of the ‘ Discovery,’’’ p. 416. 124 R.W. Brydone—Further Notes on the Trimmingham Chalk. now within the Arctic circle glaciers have streams of running water issuing from their fronts; there must have been, therefore, very great erosion in the glacier valleys by running water during the maximum glaciation, and the valleys became rapidly deepened. When the climate became severer and the glaciers became smaller owing to insufficiency of supply, they no longer flowed down the valley as it originally existed, but in the narrower gorges excavated by the sub-glacial streams in earlier times. This fact, that during maximum glaciation there was necessarily a milder climate and consequent greater melting and erosion, may perhaps explain how glacier valleys in Europe and America have been scored by ice from their bottoms to heights of 3,000 and 4,000 feet above. To maintain that such valleys at one time were filled from top to bottom with ice is, to my mind, equivalent to saying that in an ordinary river valley, with terraces high up the sides, the valley was once filled with water from the present level to the topmost water-mark. Vi.—Furtuer Notes on THE STRATIGRAPHY AND FAUNA OF THE TRIMMINGHAM CHALK. By R. M. Bryponz, F.G.S. (PLATES VIII AND IX.) (Concluded from the February Number, p. 78.) ie, very uniform trend of all these ridges will have been noted, but my previous remarks on the general strike of the foreshore chalk require considerable modification. The whole of the chalk so far exposed may be divided into four sections. Hach of these comprises an exposure in or close to the cliff of what appears to be the highest part of a ridge running down the beach in a direction from 10° to 80° south of east (and sinking as it goes) to about the half-tide level. Here three of them (the exception being the brickfield chalk) turn and run for some way roughly parallel to the shoreline, and then resume their original direction and run out to sea. The brickfield chalk only varies from this plan by running out to sea with practically no change of direction on the way. Except where a ridge is running up to the cliff, the substratum of the beach is invariably glacial clay down to about half-tide level. Here it is either banked against what appear to be vertical faces of chalk or else (between the foreshore exposures) disappears under the sand. It has never been seen to run out to sea, and every time a fresh bit of the foreshore below the half-tide level is cleared of sand it is chalk that is revealed. In the case of the section attached to the north bluff there is below the half-tide level a continuous mass of chalk with perfectly regular bedding exposed for at least 1,000 yards along the shore, and directly opposite the north bluff I have myself seen chalk continuous from the foot of the bluff for over 200 yards straight out to sea (except about 20 yards close up to the bluff, which, however, are covered by Mr. B. B. Woodward’s letter in the October (1905) number of the GronoaicaL MaGazine), the regular sequence of the beds being only broken by R. UM. Brydone—Further Notes on the Trimmingham Chalk. 125 one fault. The section attached to the ridge coated with a sheet of flint is a good second in size, showing chalk in regular sequence for a length of over 400 yards, and maximum (exposed) breadth of about 45 yards. There seem to be only two possible theories as to the nature of these chalk masses, as Mr. Reid’s theory is quite impossible of general application, and appears to be only applicable to the north bluff subject to very important modifications. One is the erratic theory. This theory involves the possibility of an erratic 1,000 yards by 200 yards in superficial area and unknown depth, and others smaller but still of monstrous size. It offers no explanation of the rude symmetry of tectonic structure exhibited by the chalk, nor any plausible origin for these erractics, which have no known counterpart in fossil contents, and cannot from the perfection in which they have retained their stratification and fossil contents have travelled far. It is also a coincidence almost past belief, until every other possible explanation has failed, that an ice-sheet should chance to leave at one spot all the known remnants (a very large number) of a very strongly marked epoch without the admixture of a single erratic mass belonging to any other epoch. If a final nail in the coffin of the erratic theory be required, it is to be found in the Mundesley well section recorded in the Geological Survey Memoir on the Upper Chalk of England as having shown a great thickness of chalk, obviously in sitz, containing O. lunata at intervals. The other theory is that of the buried chalk cliff, set forth in my previous pamphlet (of which Mr. Jukes-Browne’s buried sea stacks are really a variant very near the truth, but not quite borne out by my investigations). The numerous sections on the foreshore where the clay is piled up against apparently vertical faces of chalk, the uniformity with which the clay has hitherto been found to be bounded to seaward by chalk, the occasional disturbances in the chalk along its junction with the clay never penetrating more than a short distance into the body of the chalk, the newly exposed cavities in the southern part of the south bluff, and the great masses of flint shingle in the cliffs immediately above the bluffs, all tend strongly to confirm the supposition that the chalk once presented at this point a low cliff with projecting headlands to a sea lying where now we have the land, and that up against this cliff the boulder-clay was piled. It is not at all uncommon to find the chalk much disturbed along the junction with the clay, while a few yards further seawards there commences an extensive area of wholly undisturbed chalk, and this is no doubt due to the dislocation of the chalk in the face of the old cliff by clay forced into cracks and acting under continued pressure from behind like a gigantic wedge. The erratics behind the north bluff have almost demonstrably been torn from the parent mass by clay pressing up from below, which must have reached a position below them either in caves or along cracks. There are, as will have been gathered, many apparent instances on the foreshore of clay passing under the chalk. Some of these are 126 R. W. Brydone—Further Notes on the Trimmingham Chatk. undoubtedly genuine cases, to be explained as above. But itis quite possible that the majority are only apparent. If boulder-clay was banked up against a vertical wall of chalk, the plane of junction would often be a waterway of some importance. The water percolating along this plane would, of course, have little or no effect on the boulder-clay, but would tend to dissolve away the chalk, and the deeper below the surface the water got the greater would be the pressure on it and consequently its solvent power. There would thus be a constant tendency for the chalk face to recede, and recede less rapidly at the surface than deeper down, and so to develop an over- hanging vertical face. The clay, being comparatively plastic, would of course follow the receding chalk wall, and in time lie under the chalk for a short distance. The shortness of this distance would not be apparent in the foreshore sections we have, which are almost always along the chalk walls and never across them, but I have several times been able to satisfy myself by digging that the distance for which the infraposition of the clay to the chalk extended seawards was a matter of inches only. It may perhaps be permissible to speculate on the epoch at which this chalk cliff existed. Now we know, of course, that the early Crag sea was a warm and tranquil sea, and therefore it must have been protected from the North Sea of the period by a land barrier, the gradual breaching of which would allow the gradual admission of colder water and Boreal forms, which can be so clearly traced in the upper Crag beds. Such a barrier, if it lay anywhere in or near Norfolk, must have been of chalk, which is the basement bed, so to speak, of the county, and we should therefore hope to find with great luck the cliffs left by the cutting through of the barrier, and possibly also the floor of chalk formed in the gap. Now we have between Cromer and Weybourne an almost flat surface of chalk at sea-level, which presumably has not been formed by the recent sea, as the cutting back of the cliffs always reveals a platform of chalk at their very base, which, except between Sheringham and Weybourne, shows no sign of rising into the cliff, and therefore must be of pre-glacial age. Is it fantastic to suggest that the chalk between Cromer and Weybourne is part of the floor of the old breach, and that at Trimmingham we have the only remains yet disclosed of the east cliffs formed by that breach, and that the west cliffs are buried at some point between the chalk at sea-level round Cromer and the chalk at a considerable height above it round Holt and Melton, a slight tilt having brought the cliffs at Trimmingham nearly down to modern sea-level ? The behaviour of the Pliocene beds themselves confirms this supposition as to the relative Pliocene positions of the Trimmingham and Cromer chalk, for the Pliocene beds near Cromer are all above the surface of the chalk there, while we know on the authority of Mr. Reid that corresponding Pliocene beds at Trimmingham close by the chalk occur well below high tide mark, and consequently many feet below the highest point to which the undisturbed chalk there reaches in the south bluff. This theory would involve the existence at one time of a (probably now buried) R. W. Brydone—Further Notes on the Trimmingham Ohalk. 127 — chalk cliff running along the bed of the North Sea, and such a cliff would be a possible source, and the only one that can be suggested, for the erratics between Trimmingham and Weybourne. Some cliff the source must have been, for ice with all its powers can neither shovel up nor suck up large masses of chalk out of a horizontal surface. This hypothetical buried cliff would probably be running more or less north and south, and would therefore be nearer to the present coastline at- Overstrand than further north, and the difference in distance travelled would account for the enormous difference between the condition of the Overstrand erratics, which have suffered somewhat, but not much, from pressure, and those west of Cromer, which have been crushed until they are barely coherent, and crumble most rapidly on exposure. The suggested Pliocene chalk cliffs would also afford a source for the enormous supply of carbonate of lime which must have been required for the building up of the vast masses of shells of which the lower Crag beds are composed. [After this paper had taken more or less its present shape, Professor Bonney and Mr. Hill published in the GxronoercaL Magazine for September, 1905, a paper dealing somewhat sketchily with the purely stratigraphical aspect of the Trimmingham Chalk on apparently very incomplete data. This paper has been effectively criticized by Mr. B. B. Woodward in the October number of the same Magazine, pp. 478 and 479, and by Sir Henry Howorth in the November number, and I have nothing to add to the criticisms made by these gentlemen, to whom I am much indebted for their intervention. We have, however, to thank Professor Bonney and Mr. Hill for a record of chalk at the base of the cliff under Trimmingham itself, where I have long expected it, but never had the good fortune to see it. | PALONTOLOGY. A. Chalk of Trimmingham. The greater number of the additions and corrections to the list given in my previous pamphlet have been incorporated in the list to be found in the recent Survey Memoir above referred to, but for convenience a complete list of all corrections and additions is given here :— SPONGIDA. Add Porosphera globularis, Phill. ; Ventriculites decurrens, T. Smith; V. impressus, T. Smith; V. quineuncialis, T. Smith; V. radiatus, T. Smith. Omit P. Woodwardi—the light recently thrown by Dr. Hinde on the species which has so long borne this name makes me doubtful if I can prove its occurrence. ACTINOZOA. Add Diblasus Grevensis, Lonsd. Omit Calamophyllia faxeensis—the specimen which distantly suggested this species to Protessor Deecke has proved to be a fish-spine (Celorhynchus cretaceus) ; Onchotrochus serpentinus—this appears to have been based on specimens of a very slender Porina. HcHINODERMATA. Add Epiaster gibbus, Lam. ; Micraster cor-anguinum, Klein. One specimen of the former and two of the latter are in the collection of Mr. Savin. Echinoconus Orbignyanus, Ag. (the bun-shaped Hehinoconus of my previous pamphlet according to Mr. Sherborn). 128 R&R. MW. Brydone—Further Notes on the Trimmingham Chalk. f CrRRHIPEDIA. Add Pollicipes fallax, Darw. (very abundant). Substitute Brachylepas eretaceus, H. Woodw., for Pollicipes eancellatus, which has proved to be a synonym. : Potyzoa. Add Siphoniotyphlus tenuis, Hag., a species of remarkable range for one so specialised. LAMELLIBRANCHIATA. Add Avicula ceerulescens, Nilss. ; Ostrea canaliculata, Sow.; O. inequicostata, S. Woodw.—if the Trimmingham specimens are rightly identified, this species can hardly be identical with O. semiplana, as suggested in the recent Survey Memoir ; Plicatula sigillina, 8. P. Woodw.; Spondylus spinosus, Sow. Correct. Diceras ineguirostratus in Survey Memoir. This record appears to be founded on adherent valves of an Exogyra so identified at South Kensington. GASTEROPODA. Add Dentalium sp. There frequently occur casts of Gasteropods, mainly Trochus. and Cerithiwn, but so small and delicate as to require an expert to identify them. CEPHALOPODA. Add Bayfieldi, F. & C., after Nautilus. Substitute Aptychus rugosus, Sharpe, for A. peramplus. Omit Belemnitella sp. Dr. Blackmore is convinced that the very numerous specimens: of this slender form are only young &. mucronata, the infant mortality among which must have been terrible. PIsczs. Add Celorhynchus cretaceus, Dix; Corax sp.; Scaphanorhynchus subulatus, Ag. It will, perhaps, be well to comment on some _ statements. made by Dr. Rowe in his paper on the Dorset Chalk, in which he compares the fauna of the B. mucronata zone in Dorset and Norfolk, as they are calculated to mislead anyone having only a slight knowledge of the Trimmingham fauna. Je states that Pecten concentricus is common at Trimmingham. As I have never seen a specimen of it there, I can only conclude that he is confusing the smooth Pecten Nilssoni (which is common at Trimmingham) with P. concentricus. He also states that a certain hexagonal Serpula was considered by me to be S. difformis, but that it differed from the Trimmingham examples, “ which are always pentagonal.” He has here confused at least three perfectly distinct species. ‘The first is a free-growing, tapering, uniformly heptagonal form of carious surface, which is either S. difformis or a very near relation. This form, or one barely separable from it, occurs also in the B. mucronata chalk of Hampshire down to its base. The second is a very remarkable form with a polished surface. It starts with a broad base and triangular cross-section with a strong dorsal carina, and is then incapable of being separated from S. macropus. But very soon the tube rises free from the base and proceeds to develop six more caring placed at regular intervals round the tube. But the new carinz are not all developed at once, and the specimen forwarded to me by Dr. Rowe for identification was, if I remember rightly, a youngish specimen with six carine fully developed and the seventh just appearing. This form is not uncommon in the B. mucronata chalk of Hampshire, but I have not yet found it (at any rate, to be certain of it) at Trimmingham. At the time I saw Dr. Rowe’s specimen I was still under the impression that this form would prove to be GEOL. MAG. 1906. Dee Vi, Vols Ile ei valle Views of the Trimmingham Chalk Bluffs, Norfolk Coast, (To illustrate Mr. R. M. Brydone’s paper.) c++ —- 64 €.0¥ . . i oe * ‘ : ‘ j F Ee ad ‘ . -* 7 f. ~— s e i ‘ 5a “ ae a r Re - ‘ ¥) f * . an ® * ‘ A a ' 4 . - A . 7 \ a é ws i hoa A ' 7 f . , ) ‘ 7 { h : 0 7 ry . te ™ ee gto tee 3 “ie! Si - \ }) . ‘ q ’ He om We zaas ; ' oe . a - , . . ’ ‘* «a * - KR. M. Brydone—Further Notes on the Trimmingham Chalk. 129 S. difformis, so I gave this name to Dr. Rowe, but with the same caution with which, it will be seen, I recorded it at Trimmingham in my previous pamphlet. Whether it ought to be included in the same species as the typical S. macropus on account of its initial stage is a question for a specialist, but it seems to me very undesirable, seeing how greatly the two forms differ in the adult stage. (The question is further complicated by a Trimmingham species, which generally begins with a macropus stage like the form just described, and then grows to a great length as a free round tube slightly curved, with a carious surface and devoid of carinew. The same form is, however, often to be found in the same beds free from its earliest infancy.) 8S. canteriata, the third species, is evidently the Trimmingham form which Dr. Rowe bad in mind, as it is the only free pentagonal species at Trimmingham (except occasional specimens of S. fluctuata). Not content with gratuitously attributing to me an intention to identify his specimen of a heptagonal form with S. canteriata, which is never even hexagonal, he has made misstatements about that species from which a wider experience would have saved him. If he had said it was always pentagonal outside the Trimmingham Chalk he might well have been correct, as I have found only the pentagonal form in the various zones down to WM. cor-testudinarium, in which it occasionally appears, but in the Trimmingham Chalk it is often tetragonal, and in some specimens passes from the one form to the other. Dr. Rowe may be right in saying that Pentacrinus Agassizi and Bronni are very common at Norwich and Sheringham, but I confess I am much surprised at the statement, for I have not found a specimen of either form at either locality, and I have spent much time on the chalk around Sheringham, though comparatively little on that around Norwich. B. Chalk between Cromer and Weybourne. SPONGIDA. Porosphera globularis, Phill. (very Ventriculites impressus, 'T. Smith. large). V. radiatus, T. Smith. ACTINOZOA. Asogaster eretacea, Lonsd. Trochosmilia (laxa ?). Stephanophyliia Wichelini, Lonsd. (common). KcHINODERMATA. Bourgueticrinus (joints, including one Echinoconus vulgaris, Rom. variety very typical at Trimmingham). Zchinocorys vulgaris, Breyn. Cardiaster sp. Goniaster (ossicles). Cidaris. Micraster cor-anguinum, Klein Cyphosoma (Kénigi?). (common). VERMES. Serpula ampullacea, Sow. Serpula granulata, Sow. S. canteriata, Hag. S. gordialis, Schloth. S. carinella (2), Sow. S. litwitis, Detr. S. difformis (?), Dix. S. plexus, Sow. S. fluctuata, 8. Woodw. DECADE Y.—VOL, III.—NO. III. 9 130 R. W. Brydone—Further Notes on the Trimmingham Chatk. CrrRHIPEDIA. Brachylepas cretacea, H. Woodw. Scalpellum maximum, Sow. Pollicipes glaber, Rim. Ponyzoa. Homalostega pavonia, Hag. Pachydera grandis, Mares. Membranipora clathrata, Reuss. Porina filograna, Goldt. Many others of (at present) unknown zonal significance. BRaAcHIOPoDA. Crania Egnabergensis, Retz. Terebratula carnea, Sow. C. Parisiensis, Defr. T. obesa, Sow. Magas pumilus, Sow. (very common), T. sexradiata, Sow. Rhynchonella limbata, Schloth. Terebratulina striata, Wahl. Rh. plicatilis, Sow. Thecidium Wetherelli, Morris. Rh. Reedensis, Eth. LAMELLIBRANCHIATA. Avicula cerulescens, Nilss. Pecten pulchelius, Nilss. Inoceramus sp. P. quinguecostatus, Sow. Lima granulata, Nilss. P. undulatus, Nilss. LL. pectinata, D’ Orb. Plicatula sigillina, 8. P. Woodw. Ostrea canaliculata, Sow. Spondylus Dutempleanus, D’Orb. O. inequicostata (?), 8. Woodw. S. latus, Sow. O. vesicularis, Lam. S. spinosus, Sow. Pecten cretosus, Defr. CEPHALOPODA. Aptychus rugosus, Sharpe. Belemnitella mucronata, Schloth. A Pisces. Enchodus sp. It is perhaps desirable to mention that these fossils come mainly from the western part of this chalk, i.e. about Sheringham and Weybourne. It may be partly owing to the greater facilities for collecting offered by the cliff exposures near Weybourne, but I have no doubt that it is also due to a genuine increase in the abundance of fossils as we get away from Cromer, where the chalk is wonderfully barren. Travelling in this direction, we are, according to Mr. Reid, passing from newer to older chalk, but I have great doubts about this. The only argument he adduces to support this view is that the dip of the chalk in the cliffs near Weybourne is to the east, and may be assumed to continue all the way (there certainly does not appear to be any traceable dip in any direction in the chalk on the foreshore). I have always doubted the existence of this steady eastward dip, and when in 1903 the chalk near Weybourne was exceptionally well exposed after a storm I studied it very carefully. I was able to trace the lines of flint very minutely, and I was absolutely convinced that for nearly three-quarters of a mile from Weybourne Gap the lines of flint are dipping steadily to the west. I have also observed indications that there is a syncline at West Runton, and not very far away a chance hole in the chalk with vertical sides showed a section across a flint line apparently lying in a small anticlinal. I am therefore more inclined to regard this chalk as, at any rate, undulating, if not actually dipping westward on the whole. The fossils of the chalk around Weybourne show a tendency towards the Trimmingham fauna, and it would be remarkable if between that chalk and the Trimmingham Chalk there really lay the very unfossiliferous chalk nearer Cromer. GEOL. MAG. 1906. De We Wool, IONE, IN, IOs Be eT oa: Pe td Views of the Trimmingham Chalk Bluffs, Norfolk Coast. (To illustrate Mr. R. M. Brydone’s paper. ) Dr. H. Warth—Chemical Classification of Igneous Rocks. 131 An Appendix will follow, later on, with figures and descriptions of the Cirripedia and Polyzoa.—R. M. B. EXPLANATION OF PLATES. Prats VIII. Fic. 13.—North Bluff, seaward aspect ; May, 1905. 14.—North Bluff, seaward aspect, showing (but only faintly, owing to shadow) the chalk roof over the clay pinnacle. 15.—October 2nd, 1905, showing the aspect from the head of the south bay the day after the chalk roof was broken through. Puate IX. Fig. 16.—October 2nd, 1905. South bay. », 17.—October 2nd, 1905. », 18.—October 16th, 1905. LP) ) VII—A Mernop or Crasstrying Iannous Rooks accorRDING TO THEIR CHEMICAL CoMPOSITION. By Dr. Huenx Wartu. (WITH A FOLDING TABLE.) HE chemical classification of igneous rocks is rendered difficult by the large number of substances which are present in them. H. 8. Washington, who based his system of classification upon the composition of standard rock-forming minerals, found it necessary in his great work! to divide his 2,880 rocks into no less than 167 final groups in order to ensure a close proximity between the rocks within each group. The number of rocks in any system of classification must rise so much more rapidly the greater the proximity of the individual rocks to each other. In the case of only a single constituent the deviation of individual rocks from the group average is inversely proportional to the number of groups. A similar law prevails when several constituents are considered at the same time, as will be shown in the following. Five hundred rock analyses were selected at random for the purpose of classification. The average composition of this whole assembly of rocks was then calculated, and the mean deviation of the several substances was found by deducting the percentage of each substance present from the mean percentage of this substance in the five hundred rocks. The differences obtained for all the rocks, positive as well as negative, were then added together, and the sum-total divided by 500 gave the mean deviation of each substance. It requires to be noted, however, that for the present purpose some of the substances were taken two and two together, and their combined deviations were thus ascertained. The following is the result :— 500 Rocks. SiO, Al,O3 Fe,03; FeO MgO CaO Na,O K.0 Average composition ... yA) iby) 8) I) eI Be) | PE) Te —S$ SS —/ Mean deviation ... = aia 926 3:0 4:0 7:0 2°6 1 H. S. Washington, ‘‘ Chemical Analyses of Igneous Rocks’”?; Washington Government Printing Office, 1903. 182 Dr. Hugh Warth—lgneous Rocks Classified The total mean deviation is 26:2. In the above average we omitted 5 per cent. TiO,, -2 per cent. P,O;, 1:9 per cent. H, 0, because these substances are excluded from the partition scheme. The next step that may now be taken is as follows :—Divide the 500 rocks into two kinds, those which have less than the average of 57:0 per cent. silica and those which have more. I find that 265 rocks belong to the former with an average of 48:3 per cent. silica, and 235 rocks to the latter class with an average of 66:9 per cent. silica. The mean total deviation within these two groups has now been reduced from 26:2 to17-1. Dividing these two groups once more according to their silica percentage, one obtains four groups with respectively 43-4, 52:5, 61:0, and 72:7 per cent. silica. The average deviation is now 13:2, or about one-half of the original. It happens that these four groups nearly coincide with the old- established division of rocks into acid, intermediate, basic, and ultra-basic rocks, and it is noteworthy that this very simple classification reduces the deviation already to one-half of its original amount. As will be seen later on, it needs four times as many groups to reduce the mean total deviation to approximately one-third of the original deviation, and H. §. Washington’s elaborate system reduces it at the most to one-fourth. If the above-mentioned fourfold grouping of the 500 rocks be continued by now partitioning according to the percentage of alumina, eight groups are obtained with a deviation of 10:9. Further partition into 16 groups yielded different results according to the choice and order of substances. The following deviations are obtained :— ORDER OF SUBSTANCEs. Toran DEyraTIon. Fe, O03 + FeO, MgO + CaO, Al, 03, NazO + K2 0 sds 10°5 Fes Os + FeO, Al, Os, Mg O + Ca, Na2 0 + K20 a 10°4 Si O,, Fe, O3 + FeO, MgO + CaO, "Na, O + Ke O fA 10:2 SiOz, AleO.s, MgO + Ca 0, Na, 0+ K,0 ©.:. ae 9°7 Four bases, three last bases, two last bases, Na, O + K> 0 9°5 All four sets of bases, omitting successively the following : Al, O3, Fe. 03 + FeO, MgO + CaO, Na2O + K20 a0 9-0 This last method of grouping, which gave the best result, is herewith adopted for use. Further partition into 32 groups reduced the total deviation as follows :— ORDER OF SUBSTANCES. ToraL DEVIATION. Fez Os + FeO, Al, O03, Mg O + CaO, Na,O + K, 0, all bases ie | All bases, successively minus the following: Als Os, Fe. Os + FeO, Mg O + CaO, Na, O + K, 20, and finally all bases (with a few modifications) <> 74 The same principle might be applied for the purpose of still further subdivision. With 128 groups it would be possible to treat all the seven bases separately. It would, however, be necessary to employ a larger number of analyses to secure accuracy. 133 by their Chemical Composition. 416 LIMBURGITE, 15 LEUCITITE. con. Rock 9700. SZ: Ds) : Ss ASS “ 5 14 PICRITE. @ ceeme enw eee 13 GABBRO. 12 BASALT. TEPHRITE. 10 DOLERITE. 9 DIORITE, 11 as Se ee ee er Cee AVERAGE. fe} 8 NORITE. 7 PHONOLITE. 6 ANDESITE. 5 TRACHYTE. 4 GRANO-DIORITE. 3 GRANITE. 2 GRANITITE. RHYOLITE. SOf5 1384 Dr. H. Warth—Chemical Classification of Igneous Rocks. My present object is to employ a moderate number of divisions, and for this purpose 16 groups appear to answer best. The com- bination of similar bases has enabled me to simplify the system. The individual bases maintain generally a correct proportion, and when they do not the bases of a pair may easily be understood to replace each other (see Table II). The separate table (Table I) shows the average compositions of the 16 groups which are here used. There is added for each group the name of a typical rock which occurs in the group. To facilitate the discussion of the table I also add a Diagram (p. 133) which requires some explanation. The vertical bands of the diagram are of such widths that they represent by the scale the average percentage of the seven basic oxides and of water. If a line be drawn from point O of the diagram inclined at 45°, and if we then measure from the intersection of that line with the right margin of each band along that margin the sums of the bases Al, O;, Al, O,-+ Fe, O;, Al, O;-+- Fe, O,-+ Fe O, etc., etc., we obtain a straight horizontal line which stands for the average of 500 rocks. If we apply the corresponding numbers for any one of the rock groups we obtain the curves shown on the diagram. The acid rocks have descending curves, the basic rocks have ascending ones. The descent of a portion of any curve implies that the proportion of the respective bases is below the average, and vice versé. Horizontal portions occur in a curve whenever the respective components are equal to the average of the 500 rocks. In order to illustrate further the degree of proximity within the groups of rocks I herewith give an example of an entire group (Table II). This group No. 9, 6 aaa, has a mean total deviation of 9:4, which is very close to the average of all the groups and will therefore give a fair idea. Other more acid groups would show a greater proximity, whilst the most basic groups would be most divergent, as may be seen on the above-mentioned Table I. ScHEME oF Dryision mnto 16 Rocx-Grovups. I 24°8 a | b | | a 284: 37°4 Gay? |e a | 4 | | | | ca 24:29) 32°9 Bw 30°9 Ne a | b a (eee a | 6b | | | | | | | IV 16°5 22°6 30°4 28°7 40°9 42°4 49°3 46°4 Pt tet t+. to iS Groups eel 2 Smee Ol in 3S 9 10. 12 12°18) TA ibeetG GV OV AG tbe 1a 0! a en a 1. 2a b i. YO Gia Although the above system is only based upon 500 selected rocks, any number of others may be incorporated by following the same standard averages. In the separate Table I, the averages are given which served for the establishment of the 16 groups. 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F.G¢ 9 & ie ¥-9 “opTPOWOY 6& T-001 GG 8-¢ TL Galt Ge 1G 6-4 6-61 G- $-8¢ 0 9 ie £-9 “opsopay LE 1-001 9-1 0-6 &-8 G9 €-§ v8 6: FL G & G-89 Q © (Zs €-9 “aq qousy, LE 1-001 L-1 €-€ 6-4 9-€ 9-1 8-1 §-Z Sole fil ile g- 6-69 ee Led “a4 LLOIp-0Uw.Ly 64 1-001 G1 9-6 P-& oS oll 8-6 0-6 9-41 I: &- 9-69 qe F-¢ “OPIWB.IL) If 1-66 GI 9-5 8-& I-I #- 0-1 0-6 6-F1 I: 9-02 a LG “oppure ry) 96 6-66 ¢-T G-§ 1-6 8-1 8: O-T FT 0-FI I: ia Q Be 4-9 ayo cg 0-001 || 8-1 | 6€ €6 | 8: F- fs) ook | Po | I. | #-92 o oy noured | “omen ood [ato | aor, | 0H | Off O*N| OD O4W | Ona *O%a| *O'Ty |/#0%n Om) Olsens ‘SdNOUD-MOOU CALdOGVY NAWLXIS AHL AO NOILISOdWOD AOVUHAV—T ATEVL “9061 “2VW > : - = ee ” € 7 = 7 et oD aie = ; 7 =e Ca - ac <" 2s Seatreed © - ?. ee F iat . j b= E a ©. eed Sa ee % o “a cs > eg Sa 7 7 —> oe » ; Pena os irra ferize [ee jhe ~_——<— i 7 . o* =o 4 * = — i a a i err ey ' - Po an ’ yj " rf > . ae Yate ve i wa KPper: io 9Regar cae ae | of aie) 2 Se 7 ge ey te 7 a . ~~ — an oe aml ca anil — ——— Oe —_ — —_ —— —_ — — — — — 7 ~ - . . -_ = P; : —_ —_ = - ——o = Reports and Proceedings—Geological Society of London. 189 from the actual bones out of the Oxford Clay near Peterborough, obtained by Mr. A. N. Leeds; the fine series of Ichthyosaurs and Plesiosaurs on the walls; the reproduction of the Bernissart Iguanodon from Belgium, in the centre of the gallery; and lastly, the reconstructed skeleton of Polacanthus Foxii, an armed reptile from the Wealden of the Isle of Wight (see Grou. Maa., June, 1905, p. 242, Plate XII), make up a most attractive and striking display of Mesozoic Reptilian life. The Fish Gallery has always been a magnificent exhibition, and is still unsurpassed by any other in the world. In addition to all his other work Dr. Arthur Smith Woodward has spent 18 years in the production of four large volumes on the series of Fossil Fishes, covering 2,393 pages of text, with 138 text illustrations and 70 plates, including a large number of very beautiful outline restorations of special genera. The latest wonder is a tail of the gigantic Leedsia problematica, from the Oxford Clay of Peterborough, mounted on the east wall between cases 138 and 14. It has a span of 9 feet, and probably represented a fish 30 feet in length! The series of remains of giant armoured Devonian fishes from Ohio of the genus Dinichthys deserve to be specially mentioned, and the nearly complete examples of sharks, Cladoselache, from Cleveland, Ohio (also of Devonian age), some of which were 5 to 6 feet in length, showing the jaws with teeth, the paired fins and tail, with the outline of the body. Another group of curious Palzozoic sharks, with a coiled up series of teeth (to which the genus Hdestus Davisii belongs, see figure and description, Grou. Maa., 1886, p. 1, Plate 1), has been discovered by Professor Karpinsky in the Permo-Carboniferous of Perm, Russia, having a coil of teeth so symmetrically arranged as to present a close resemblance to an Ammonite or other discoidally coiled fossil shell. We wish that space permitted a longer notice, for the collections here described and illustrated so profusely in this little Guide, deserve to be even more widely known than they are; but such excellent handbooks, at so small a price, are sure to attract students; even the ordinary visitor, more bent upon pleasure than instruction, cannot fail to be delighted and amused and take away with the book some grains of knowledge. But it is especially for the young that these beautiful guidebooks are intended, and we hope the pictures may prove an attractive bait to many boys and girls who may thus turn out to be the geologists of the future. IS JIS OusIyS! LNaSD) IS sSsx~OrOus aD ALIN KE TS GeroLocicaL Socrmry or Lonpon. I.—January 24th, 1906.—J. E. Marr, Sc.D., F.R.S., President, in the Chair. The following communications were read :— 1. “On the Igneous and Associated Sedimentary Rocks of Llangynog (Caermarthenshire).” By T. Crosbee Cantrill, B.Sc., and Herbert Henry Thomas, M.A., F.G.S. 140 Reports and Proceedings—Geological Society of London. Tho sedimentary rocks associated with the various igneous masses comprise the following :— Lower Oxp Rev Red marls and sandstones, with cornstones and conglomerates at SANDSTONE. the base. heaateeceard bifidus Beds. Blue-black shales, with one or ORDOVICIAN more thick bands of grit towards the base. (ARENIQ). Tetragraptus Beds. Black and buff shales with thin grit bands: thick bands of ashy grits and conglomerates towards the base. These rocks are described in detail. They occur in two main anticlines, overfolded, and complicated by thrusts which cut out a great part of the intervening syncline. They are covered unconformably by the lower beds of the Old Red Sandstone. The igneous rocks occur in three well-defined areas, which belong to the same petrographical province, near Coomb, at Capel Bethesda, and at Lambstone. Both interbedded and intrusive rocks are represented, and full petrographical descriptions of all types are given in the paper. The latter include diabases, and the large porphyry mass of Lambstone. The extrusive rocks have been determined to occur in the following order :—(1) augite-andesites; (2) rhyolites ; and (38) augite- andesites, with some hornblende-andesite. The extrusive rocks are interbedded with fluxion breccias and with tuffs ;, they are associated with the lower members of the Tetragraptus Beds, and are consequently of Lower Arenig age; while the intrusive rocks have been injected into the extrusive rocks, and have also affected the Tetragraptus Beds, but at what date exactly it is impossible to say, except that it antedates the Old Red Sandstone. Much of the folding and faulting was accomplished before the Lower Old Red Sandstone was deposited, but certain faults involve this formation, and make it clear that there was an important later movement. “The Buttermere and Ennerdale Granophyre.” By Robert even Rastall, B.A., F.G.8. (Christ’s College, Cambridge). This paper embodies the rou of field-mapping and microscopical study of the large mass of igneous rocks known, collectively, as the Buttermere and Ennerdale Granophyre. From the facts put forward it is concluded that the intrusion is an example of an acid magma, which has crystallized under the peculiar set of conditions that gives rise to a very perfect development of granophyric structure. These conditions are probably, to a certain extent, intermediate between those of plutonic and true hypabyssal rocks. The masses appear to be of the ‘ cedar-tree ’ laccolite type intrusive about the junction of the Skiddaw Slates and the Borrowdale rocks, but penetrating into the higher rocks. Besides the normal acidic rock, which comprises the bulk of the intrusions, there are some marginal patches of more basic character, showing obvious genetic relationship, and slightly earlier in point of time than the intrusion of the acidic rock. These basic forerunners afford evidence of differentiation of the magna before intrusion—an example of Professor Broégger’s deep magmatic differentiation. Considered as a whole, the character of the magma shows closer affinity to the tonalite Reports and Proceedings—Geological Society of London. 141 group than to the true granites, although it is somewhat more acid than the majority of tonalites. The more basic types include dolerites, quartz-dolerites, and a rock type intermediate between quartz-dolerites and granophyres, for which no satisfactory name seoms to exist. There is also a development of peculiar rock types as the result of the re-mixing of previously differentiated partial magmas of an acid and a basic character respectively. A study of the distribution of different types of granophyric structure shows a certain regularity of arrangement, and an attempt is made to reconcile these with known physical laws, especially with reference to eutectics; and it is concluded that the structure is the result of crystallization under conditions intermediate between those which produce typical plutonic and hypabyssal rocks. I.—February 7th, 1906.—J. Hi. Marr, SoD» F.R.S., President, in the Chair. The following communications were read :— “The Carboniferous Limestone (Avonian) of the Mendip Area Bene set), with especial reference to the Paleontological Sequence.” By Thomas Franklin Sibly, B.Sc., F.G.S. The Avonian rocks are exposed in four main anticlinal forms or periclines—those of Black Down, North Hill, Pen Hill, and Beacon Hill; each of which has an approximately east-and-west trend and has Old Red Sandstone exposed in its core. The following is the zonal succession :— Zones. Subzones and Horizons. Feet. 4, } D,. Lonsdalia floriformis = 2° . | Dibunophyllwm vvccccvevees { D,. Dibunophyllum 0. \ 500 | E ; { S.. Productus aff. Cora mut. Sy. \ + 3 STEAROPUIUD eboeatoodoeuococbdcsd \iSi P) cha semiveticulatusirauts 6, 720 p SYVINGOENYTUS ......0.e0eeees C. S. cuspidata. 550 z ‘ y : Zz. Z. aft. cornucopia. 3 ZBI ENTS ean anette { Z.. Spirifer aft. clathratue. \ 800 é rec i) ( Ke. Spiriferina cf. octoplicata. ) CUAOSORG Seccansoo-nberhoes K,. Productus bassus. 450 M. (Modiola-phase.) ) In the present paper, the faunal sequence is discussed in detail, attention being confined almost entirely to the corals and brachio- pods, which predominate throughout the series. The lithological character of each zone and subzone is treated briefly. The general stratigraphy of the area is briefly discussed, reference being made to the more important forms. Following this, the exposures “examined are classified in zonal order, and tabulated under the zonal headings. The best exposures of each zone receive special attention. 142 Reports and Proceedings—Geological Society of London. A correlation with the Bristol area brings out the following more important points. The faunal succession is essentially similar in the two areas; and in both there is good ground for a twofold division into Clevedonian and Kidwellian stages, the line of separation being drawn at the top of the Syringothyris Zone. The Mendip area exhibits, however: (1) a great expansion in the thickness of the Zaphrentis and Syringothyris Zones; (2) a continuously fossiliferous sequence from the top of the Zaphrentis Zone to the base of the Seminula Zone, possessing a characteristic coral and brachiopod fauna; and (3) a relative acceleration of the coral fauna on the brachiopod fauna, exhibited in the Zaphrentis Zone. The paper contains a detailed account of the Ebbor Rocks District, near Wells, and concludes with notes on certain corals and brachiopods included in the faunal lists, together with descriptions of some new species and mutations. 2. “The Igneous Rocks of the Eastern Mendips.” By Professor Sidney Hugh Reynolds, M.A., F.G.8. The igneous rocks associated with the Old Red Sandstone of the Mendips are exposed along the crest of the range from Beacon Hill on the west to near Downhead on the east, a distance of rather more than 2 miles. Hitherto they have always been regarded as intrusive, but the opening of some new excavations has shown that they are associated with a considerable thickness of tuffs, and are in all probability contemporaneous lava-flows. The exposures show a division into three sections—those of Beacon Hill, Moon’s Hill, and Downhead ; and a large quarry has been opened in the trap in each section. The trap, which can be traced fairly continuously from one end of the area to the other, is very uniform in character, consisting (as already noted by Dr. Teall) of a non-amygdaloidal pyroxene-andesite, which usually contains augite in addition to enstatite. A fine section of tuff some 100 feet thick is seen lying with perfect conformity below the trap in the New Quarry near Stoke Lane; and an interesting little exposure of tuff, remarkable for the numerous rounded blocks of trap present, is seen in the excavation for the rifle-butts on Beacon Hill. The tuff here dips under the Old Red Sandstone to the north. Although the tuff is seen in situ only at the above two points, loose pieces have been met with at a number of other spots all along the southern outcrop of the trap, and point clearly to the occurrence of a continuous band underlying it. Though no sedimentary rocks are seen in direct contact with those of the igneous series, outcrops of Old Red Sandstone com- pletely surround the exposures of trap and tuff, and occur in such close relation to them as to leave little room for doubt that the igneous series is of Old Red Sandstone age. On the other hand, Silurian fossils were met with below the igneous series at a point to the west of Downhead, and render it possible that the igneous rocks may be of Silurian age, and the equivalents of those which are exposed at Tortworth. Reports and Proceedings—Mineralogical Society. 143 IJ.—Mineratocicat Society or Lonpoy. January 23rd, 1906; Professor H. A. Miers, F.R.S., President, in the chair.—Studies in Crystallisation, Sodium Nitrate, by H. A. Miers and J. Chevalier. Microscopic observations were made upon solutions of known strength contained in open tubes or sealed tubes maintained at a known temperature, or in the form of drops upon a slide, with the object of comparing the growth of crystals in metastable and labile solutions respectively. ‘The limits of the labile state (in which the solution can crystallise spontaneously) have been fixed by previous experiments by H. A. Miers and Miss F. Isaac. Ifa crystal of the salt be introduced into a supersaturated solution which is not labile, the centres of growth of new crystals are on its surface, and they grow in parallel positions upon it; if it be introduced into a labile solution the new centres of growth are in its neighbourhood, and the crystals fall upon it in various positions. If it be moved about in either, a cloud of crystals is produced ; but in the metastable solution this appears to be due to minute crystals which are swept from its surface. A crystal having appeared spontaneously, can continue to grow in a labile solution without producing others in its neighbourhood; but if introduced, it at once produces a cloud. This may be because the growing crystal is surrounded by a zone of metastable solution.— Geikielite and the Ferro-magnesian Titanates, by T. Crook and B. M. Jones. Geikielite occurs in association with magnesian menaccanite and common ilmenite (menaccanite) in the gem gravels of the Balangoda and Rakwana districts of Ceylon. A considerable number of analyses indicate that Geikielite varies in composition, the iron oxides ranging from 8 to 14 per cent. Nospecimen has hitherto been found which contains less than 8:1 per cent. of iron oxide. For this reason the formula (Mg Fe) TiO, is preferable to Mg Ti O,, as expressing the true composition of Geikielite. Magnesian menaccanite containing about 28 per cent. of iron oxide is very closely allied to Geikielite in all its properties, more so than to common ilmenite. The alteration products of Geikielite are similar to those of ilmenite, consisting of rutile and so-called leucoxene; the latter is a mixture of amorphous titanic acid, sphene, and limonite. Itseems advisable to classify the ferro-magnesian titanates as Ilmenites and Geikielites, treating magnesian menaccanite (which has the formula (Fe Mg) TiO; where Fe : Mg = 1: 1) as the middle member of the series.— G. F. Herbert Smith exhibited and explained the use of a diagram for the graphical determination of the refractive index from the prism angle and the angle of minimum deviation. He also explained a simple test for ascertaining the pair of faces corresponding to any refracted image. CORRESPONDENCE. MACHINE-MADE IMPLEMENTS. Sir,—Since this article appeared, I have been able, in company with Mr. C. Bird, F.G.S., of Rochester, to visit a chalk wash-mill at the Borstall Cement Works near that city. 144 Correspondence—F. J. Bennett, F.G.S. I found that the machinery used was much the same as that in the brickearth wash-mills referred to in my article of February, 1906, but I learnt this most important piece of information, not hitherto: mentioned by anyone as far as I have been able to discover, viz., that during the 2 days, or 29 hours, that the mill is at work, fresh charges of chalk are introduced; this is of the utmost importance, as it affects materially the results obtained. I had only a very short time for my visit, but I think I got all the available information. The men told me that, as at Mantes, they removed all the visible flints, so that the remaining ones, which they do not want, are those concealed in the chalk. The harrows also, as in the Mantes mills, do not come within some inches of the bottom of the basin, and the speed would appear to be the same at Borstall as at Mantes. From the flint refuse heap, “the heap of Eoliths” as M. Boule styles them, I got a very good selection, some of which, as the men were able to tell me, had been in for the full time, and some of which had been in for only part of the time. Now from those that had been in for only part of the time I got some flints that, if photographed, would give very fair samples of Koliths, though not comparable otherwise in true work, some showing bulbs of percussion and the fractures so polished that they have quite an old look. My own attempts at forgeries are useful, as they show me that I can produce in a short time this old polish, where the flint allows of this. So that 1 was quite prepared for the apparent old polish on newly fractured flints from the chalk. Some of these had still on them some of the white crust of flints fresh from the chalk. But those flints that had been in the full time were quite different from, and not Eoliths at all. These must have sunk to the bottom, quite out of reach of the harrows, the “quasi-human element” referred to in my article of February, and thus were the results ultimately of water-action only, highly charged of course with chalk mud. These come out as almost perfectly smooth spheres, and quite unlike any naturally water-worn pebbles, and what one would naturally expect to be the outcome of flints, rotated at an uniform speed in a circular basin, and under conditions that do noé occur in nature, save perhaps in a ‘ giant-cauldron.’ Those flints that go in last, especially if the spaee beyond the reach of the harrows be fully occupied, must be more or less, during that time, in contact with the harrows, and these are the pseudo-Koliths. So that we have this point, I think, clearly shown, and for the first time in this machine-made implement controversy, that the pseudo- Eoliths are the result of the pseudo-human element represented by the harrows, and that the pseudo-torrent action, apart from the harrows, only produces spheres. I made a selection of these from the battered, buffeted, rough, and imperfect, to the smooth and almost perfect sphere. F. J. BEnnett. West MAtuine. February 14th, 1906. No. 502. Decade V.—Vol. III.—No. IV. Price 1s. 6d. net. GBOLOGICAL MAGAZINE R, Monthly Sonal of Geology. WITH WHICH IS [INCORPORATED “THE GEOLOGIST.” EDITED BY HENRY WOODWARD, LL.D., F.R.S., F.G.S., kc. ASSISTED BY WILFRID H, HUDLESTON, F.R.S., &c., Dk. GEORGE J. HINDE, F.R.S., &c., anp HORACE B. WOODWARD, F.R.S., &c. APRIL, 1906. CON Tass eS: Il. Reports aNnD PROCEEDINGS. of the Geological Society ............ 145 Notes on the Corries of the Comeragh Mountains, Co. Waterford. By Geological Society of London— Annual General Meeting, Feb. 16th, F. BR. CowPEr RErp, M.A..F.G.S. 1906 aeonoon ute te reece eee ee tees sees 178 (With 5 Ghee een ileteonee and Evening Meeting, Feb. 21st, 1906 186 Plate XIII.) petelatetelatalstatelstelelstalelteletaietstsisiele 154 ILI. CornrESPONDENCE. The Geological History of South Africa. Professor A. von Koenen ............... 188 By Dr. FP. H. Haron, F-G:8., Iv. 0 M.1.C.E., President of the Geo- V. Oxrruary. logical Society of South Africa. John George Goodchild, F.G.S. 189 (Concluded.) Sie ohn wdlesaeten stove een 161 | Thomas Barron, A.R.C.S., F.G.S.... 190 . Superheated Water. By A. R. Hunz, William Cunnington, Gr Ske seer 191 4 AVP Nem Brel ec Hie GiSs cescaceccsemes 169 V. MisceLrLaneous. The Pendleton Earth - shake of Appointment of Prof. W. W. Watts, November 25th, 1905. By Cuartzs M.A., F.R.S., Sec.G.8., to the Davison, 8c.D., F.G.S8. (With 2 Chair of Geology in Royal Cae Text-[lustrations ) ........6..c.cee0 171 OMS CLEN COMET h.sincs osc wacarter: LONDON: DULAU & CO., 37, SOHO Gm inst I. Orternan Articuzes. Page OricinaL ArricLEs (continued). Page | Lamarck and Playfair: A Geological A Cordierite-bearing Lava from the Retrospect of the Year 1802. By Lake District. By ALFRED Harker, Sir ArcHrpatp GerKkre, Se.D., IW Eat Oe Sisto tit ns toto RBs cant a 3 176 D.C.L., LL.D., Sec.R.S., President ¢¢ The Volume for 1905 of the GEOLOGICAL hacasintens “i ready. merce 20e. net. Cloth Cases for Binding may be had, prigg, ts. 64. agi coo a ——_ ROBERT F. DAMON, WEYMOUTH, ENGLAND, | | Is now supplying carefully prepared Coloured Casts of the AUSTRALIAN MUD FISH, FROM THE RIVERS OF QUEENSLAND, CERATODUS FORSTERI, KREFFT. Measuring 3ft. x 10in. = 9lcem. x 25cm. Price =- £3. Also Casts of the upper and lower halves of the Head, showing Teeth, Nares, etc., lying side by side on a slab, Measuring 10in. x Gin. = 25cm. x 15cm. Price = £1 10s. ADDRESS : ROBERT F. DAMON, WEYMOUTH, ENGLAND. THE GHOLOGICAL MAGAZINE. NEW SERIES. DECADE V. VOL. Ill. No. IV.— APRIL, 1906. Oreo GaN ASE Atiee saa @Ar zens. T.—Lamarcx AND Prayrarr: A GEoLOGICAL RETROSPECT OF THE Yuar 1802.1 By Sir Arncurpatp Gerxin, 8e.D., D.C.L., LL.D., Sec. B.S., President of the Geological Society. HEN the “ Alliance Francaise” did me the honour of inviting me to give an address on this interesting occasion, the choice of an appropriate subject of discourse presented at first some little difficulty. On the one hand, as a representative of science in the *‘ Alliance Franco-Britannique,” it appeared to be incumbent upon me to choose some topic of a scientific kind, and by preference one which would in some way link our two countries together in common bonds of association. On the other hand, it was obviously inadvisable that the theme should be of a technical character which would be little suited for a general audience. After some reflection I decided to present for your consideration a brief account of two remarkable volumes, both of which, dealing with geological questions, appeared in the year 1802, the one in Paris, the other in Edinburgh. Though the political sympathies which for so many generations had linked France and Scotland in a friendly alliance had fallen somewhat into abeyance by the beginning of last century, the two nations still continued to be drawn to each other in the realms of culture by a common ardour in the prosecution of science and philosophy, and by the mutual reaction which, in these great domains of human thought, they exerted on each other. At the time which I have selected for review, the science of geology, though still in its infancy, had awakened widespread interest on both sides of the Channel. The French and English observers who pursued it kept themselves, for the most part, in touch with the progress of enquiry in both countries. Thus, it is pleasant to remember that Desmarest, one of the brightest lights in the history of French geology, though he had determined not to notice in his great “Géographie Physique” the work of living writers, departed from his rule in order to give his fellow-countrymen an 1 An address delivered before the ‘‘ Alliance Francaise ’’ in the Sorbonne, Paris, on 26th February, 1906. DECADE V.—VOL. III.—wNO. IV. 10 146 Sir A. Geikie—Lamarck and Playfair— account of the important memoir in which the illustrious Scottish geologist, Hutton, had then recently published the first sketch of his “Theory of the Harth.” On the other hand, Hutton, by the numerous references and citations in his writings, showed how closely he had studied and how generously he appreciated the publications of his French contemporaries. Looking backward to the beginning of the nineteenth century, we see the European geologists of that time ranged in two opposite schools, which might be called hostile camps, that waged with each other an animated and prolonged warfare. Not until after the chief antagonists of that time had one by one passed away did the feud finally die out. On the one side, the crowded ranks of the Neptunists marched under a banner on which was boldly emblazoned the war-cry of “ Water.” These militant theorists maintained, as the cardinal article of their faith, that our globe was once surrounded with an universal ocean, from whose waters the oldest rocks of the terrestrial crust were successively deposited as chemical precipitates. They scouted the notion that the earth possessed a highly heated interior, and nicknamed as ‘ fire-philosophers’ those who held such a belief. They contemptuously dismissed the idea that any of the rocks of the crust had been erupted from below in a molten condition. They accounted for volcanoes by boldly reviving the . ancient hallucination that they were caused by the accidental ignition of subterranean beds of coal. Hence as, on that supposition, volcanic action could only have come into existence after vegetation had flourished for a long time upon the surface of the earth, so as to form there thick deposits of combustible materials, they affirmed that the appearance of volcanoes must be a comparatively late phenomenon in the history of our planet. They had not the least conception of any source of energy lodged in the interior of the earth. The broken and convoluted rocks. of mountain - chains awakened in these men no doubt of the fundamental truth of their doctrine, for they complacently explained these stupendous structures as nothing more than the natural result of the dessication, fissuring, and subsidence of the universal aqueous deposits. On the other side of the field of battle, the phalanx of the Plutonists or Vulcanists, less numerous but not less confident and strenuous, proudly brandished their flag which bore the watchword “Fire.” With much more tolerance than was shown by their opponents, these combatants freely admitted that a large part of the earth’s crust undoubtedly consists of materials that were laid down in the sea. But they contended that the subsequent uplifting of these materials into dry land and ranges of mountains arose from the expansive power of heat within the globe. Following Descartes and Leibnitz, they conceived that this intensely hot interior was the source whence many crystalline rocks had been forced upward into the cooler crust, and that from the same source the activity of modern volcanoes is still derived. The dust and din of this warfare have long since subsided. Looking back from the point at which we have now arrived in the A Geological Retrospect of the Year 1802. 147 onward march of science, we may well wonder that such a contro- versy should ever have arisen at all, or that having been started it should have been waged so keenly and for so long. We must remember, however, that in those days the range of actual definite knowledge in regard to geological processes was still comparatively narrow, while at the same time the natural tendency to speculation and theory could be indulged in without much hindrance from the conirol of ascertained fact. On both sides of the dispute, imagination played a not unimportant part in the theoretical views proposed ; but in this respect the partizans of Water must be allowed to have stood pre-eminent. Their complacent defiance of the laws of physics and chemistry, imperfectly as these were appreciated a hundred years ago, is one of the most curious episodes in the history of geology. The advocates of Fire came much nearer to the truth as we now understand it, though they too were inclined to push their distinctive opinions somewhat further than the known facts warranted. It was while this contest of the rival schools had reached its height that the two volumes to which I wish to ask your attention made their appearance. Between the respective writers of these books—Jean-Baptiste de Lamarck and John Playfair—some curious parallels may be remarked. They were both intended by their parents to become ecclesiastics, the one in the Roman Catholic Church of France, the other in the Protestant Kirk of Scotland, but both eventually drifted into the ranks of science. Neither of them was a professed geologist, but was engaged, during most of his career, in the prosecution and teaching of widely different branches of knowledge. Both of them had passed middle life before they appear to have given much thought to the problems of geology, and neither of them published any special work on the subject save the volume which appeared in 1802. Hach was led by a different path into the geological field of observation and theory, and, so far as known, neither had any acquaintance with what the other was engaged upon. While they entered upon the consideration of the subject from opposite sides of enquiry, they both endeavoured to take a broad view of Nature in order to frame a connected scheme of geological philosophy. And lastly, both sought to establish what in the language of their day was called a ‘“‘ Theory of the Harth ’—in other words, a systematic grouping and discussion of the various processes whereby geological changes are effected. Among the recorded careers of men of science, none surely is more picturesque than that of Lamarck. Born in 1744, of an old but not opulent family long settled in Picardy, he was, as I have said, originally destined for the Church, but when a lad of no more than 17 the martial traditions of his race proved too strong to be fettered by ecclesiastical restraints, and on the death of his father he boldly set out to offer himself as a volunteer in the French Army, then at war in Germany. He arrived at the front on the eve of a battle, at which he next day so distinguished himself for his coolness and bravery that he was at once promoted on the field to be an officer. Owing, however, to an accident that happened to him not long after 148 Sir A. Geikie—Lamarck and Playfair— the declaration of peace, he had to leave the Army. Already he had acquired a strong liking for botanical pursuits, and in spite of his struggle with poverty he was able to devote himself with so much ardour and success to these studies that before many years were passed he published, under Buffon’s auspices, his ‘“ Flore Frangaise,” and was soon acclaimed as one of the most eminent botanists of his day. In watching the progress of his career we see how, through the terrors of the Revolution, he remained quietly at the post which he had obtained at the Jardin des Plantes ; how he pleaded successfully for the adequate endowment and reorganisation of that institution and of the Muséum d’Histoire Naturelle ; how at last when 50 years of age he was offered a Professorship at the Museum, not of botany, to which he had till then devoted his life, but of invertebrate zoology, which he had not specially studied ; how, with a courage and self-reliance not less marked than he had shown on the battlefield, he accepted the appointment, and after middle life began to acquire and then to teach what was to him anew science; and how before the lapse of many years he made himself the most philosophical zoologist of his time, and the pioneer of the modern doctrine of biological evolution. Year after year he continued his indefatigable researches and issued his voluminous publications, until his eyesight gave way, and he spent the last ten years of his life in blindness. But even under this grievous infliction he refused to quit his task. Sustained by the devoted affection of his eldest daughter, to whom he dictated the concluding volume of his immortal ‘“‘ Animaux sans Vertébres,” he survived to reach the ripe age of 85. During his studies as ‘“ Professor of zoology, of insects, worms, and microscopic animals,” Lamarck perceived the importance of connecting his investigation of living forms with an examination of the extinct types preserved in the various formations of the earth’s crust. He saw that the organic remains in the rocks not merely furnish materials for elucidating the structure and affinities of living animals, but supply data for the interpretation of the ancient history of the globe. So vigorously did he prosecute his researches and so deeply did he leave his mark on this great depart- ment of natural history, that he is now everywhere acknowledged to be not less entitled to the name of founder of Invertebrate Paleontology than his great contemporary Cuvier is to that of founder of the Vertebrate division of that science. It was doubtless in the course of his investigation of fossil organisms that Lamarck’s attention became rivetted to the consideration of some of the more important problems in the domain of geology. That he had pondered long and profoundly over them and sought their solution by original methods of his own device was at last revealed to the world by his publication of a treatise to which he gave the name of “ Hydrogéologie.” This was a small volume of 268 pages which made its appearance at the beginning of the year 1802, eight years after his appointment as Professor at the Museum. It never reached a second edition ; indeed, it would appear to have excited but little A Geological Retrospect of the Year 1802. 149 interest among his contemporaries. His crude speculations in physics and chemistry were not unnaturally regarded as the aberrations of a genius of which no serious notice need be taken, and his geological observations, some of which were at least as original and singular, seem to have been thought worthy of no better treatment. He inveighed against the methods and conclusions of the physicists and chemists of his day, though he does not appear to have himself studied these sciences experimentally, but to have evolved his ideas regarding them out of his own fertile brain. He went so far in his opposition to the current beliefs as to declare that even although the whole world should accept them he would be content to remain the solitary disbeliever." He would seem to have been as good as his word, and to have scouted modern physics and chemistry as long as he lived. Yet in neglecting his little volume, his contemporaries and their successors failed to perceive that amidst all its strange conceptions it made some really valuable contributions to a sound theory of the earth. In judging it we must bear in mind the general ignorance then prevalent as to what are now seen to be most obvious and elemental facts about the history of our globe; likewise the baneful influence of the orthodox theological creed that only some 6,000 years had passed away since the creation of the universe. We should remember, too, that the internecine dispute between the Neptunists and the Plutonists had brought discredit on the study of geology, which was taunted as a mere field of strife and visionary speculation, wherein men were too often guided rather by their desire to uphold their own theories or damage those of their opponents than by the wish patiently to collect the facts that would ultimately establish the truth. Lamaick belonged to neither of the hostile schools, and he makes no allusion to them in his treatise. It is refreshing to turn from the angry debates and trifling observations of the time to his calm philosophical pages, and to come into touch there with a great mind which contemplated Nature as a whole and sought after the true interpretation of her working. He was essentially a biologist, and he was led to enter the geological domain, not as a partizan of any of the theories of the day, but as an ardent enquirer into the history of life upon the earth. He appeared as a bold pioneer into the vast and still little known field of the geological past, and though, as was only natural and at the time hardly avoidable, he wandered from the track, he yet succeeded in opening up some pathways where no previous explorer had appeared, and in clearing and widening others that had already been partially trodden. One fundamental truth was vividly realised and eloquently proclaimed by Lamarck. At a time when the orthodox six thousand years were still generally believed to limit the age of the earth, he had acquired a profound conviction of the high antiquity both of the globe itself as a planet, and of the plant and animal life that has flourished on its surface. Again and again in’ 1 « Hydrogéologie,’’ p. 167. 150 Sir A. Geikie—Lamarck and Playfair— his “ Hydrogéologie” he pauses to dwell on this great fact of terrestrial history. ‘'To Nature,” he remarks, “time is nothing and is never a difficulty. She always has it at her disposal as a means without limit for the accomplishment of the greatest as well as of the least of her labours” (p. 67). ‘From the evidence furnished by the earth’s crust and by the mass of the mountains, the antiquity of this globe is seen to be so vast as to be absolutely beyond the power of man to appreciate” (p. 88). “Yet how much will this antiquity seem to increase in man’s eyes when he shall have been able to form a true idea of the origin of living bodies, as well as of the gradual development and perfection of these bodies ; and, above all, when he shall recognise that lapse of time and the necessary conditions having been required to bring into existence all the living species which are now to be seen, he is himself the final result and present maximum of this development, of which the ultimate limit, if such should exist, can never be known” (p. 89). Another essential principle of geology was recognised by Lamarck perhaps more clearly than by any of his predecessors since the time of Aristotle—the principle of constant change upon the surface of the earth. The limited range of knowledge then available on this subject prevented him, indeed, from forming any adequate conception of one great side of it. He did not recognise that besides the various agents that take their origin and do their work on the surface of the earth, there is another powerful source of energy lodged within the interior and manifesting itself from time to time by slow or by sudden movements that more or less change the face of the globe. He writes, indeed, of local catastrophes and of the elevations, subsidences, and heapings-up of material which may now and then result from volcanoes and earthquakes (pp. 88, 97), but that he could have had no adequate conception of the probable condition of the earth’s interior and of its reaction on the surface may be inferred from his still accepting the ancient error that all volcanoes on the earth derive their heat and energy from the combustion of seams of coal and other inflammable materials buried within the crust of the earth (p. 111). Nor does he appear to have had any notion of the natural operations whereby land is elevated and meuntain-chains are upheaved, for he explained these phenomena by a hypothesis which was hardly less extravagant than some of his speculations in physics. and chemistry. Thus he held that the ocean-basins have been scoured out of the surface of the globe by the erosive action of the sea, which, in virtue of its tidal oscillation and westward movement, attacks the eastern coasts of the continents, and throws up its detritus. on their western shores. He thought that in this way the vast hollow that holds the oceanic waters actually travels round the globe, and has done so completely more than once in the earth’s history, each revolution requiring a period of nine hundred millions of years. for its accomplishment (pp. 178, 266). When he contemplated the progress of the changes that take place upon the surface of the earth Lamarck stood on firmer ground, for he drew his conclusions more from the facts of observation than A Geological Retrospect of the Year 1802. 151 from the fancies of untenable theory. In his survey of these super- ficial changes he was more particularly struck by the far-reaching importance of those which result from the universal decay of the surface of the land and the removal of the disintegrated material to the bed of the sea. This impressive department of geological science had attracted attention from an early period, and had been especially studied by more than one observer during Lamarck’s lifetime. His great contemporary Hutton, for example, had made it a cardinal feature in the scheme of his theory of the earth. The French naturalist, however, though he was probably indebted to the work of his predecessors, appears to have acquired a more vivid appreciation than any of them of the several processes that con- tribute towards the universal degradation of the dry land. He perceived that nothing in Nature can ultimately resist the various atmospheric influences which are ceaselessly at work upon every portion of the earth’s surface exposed to their attacks. But in his little treatise he does not dwell on this part of his subject, contenting himself with a brief enumeration of these influences, in which he clearly distinguishes the effect of alternate wetness and dryness, of heat and cold, and more particularly of frost. The general effect of the combined operation of these subaerial agencies is pronounced by him to be the ultimate destruction of every aggregation of mineral matter, although the rate of advance of this disintegration must greatly vary, according to the nature and condition of the materials on which it acts (pp. 10, 11). In one important respect Lamarck’s outlook upon Nature differed from that of any previous or contemporary observer who occupied himself in the study of geological processes. Before his time it was the inorganic series of these processes which almost exclusively received attention. But Lamarck was led to contemplate the whole subject from the biological side. His long years spent in the investigation of plants and his subsequent absorbing researches in the animal kingdom had profoundly impressed him with the im- portance of what he called the ‘ Pouvoir dela Vie’—the power of living organisms to build up substances and structures which could have arisen through the operation of no inorganic agents. He had already, in some of his published memoirs, called attention to this great subject and formulated some of the conclusions to which he had been led, and he now devoted to its discussion the longest chapter of his little geological treatise. To him the processes of life formed one of the grand elemental forces of Nature, independent of but co-operating with the various physical agencies in building up the materials of the terrestrial crust, and in effecting the constant decay and reconstruction of the surface of the earth. It is only of late years that the efficacy of plant and animal life, as a department of dynamical geology, has been generally recognised, although we are still far from having discovered all the various ways in which organic bodies, living and dead, produce changes in the mineral kingdom. There can be no doubt that in this matter Lamarck realised far more clearly than had ever been done before that the organic world 152 Sir A. Getkie—Lamareck and Playfair— plays an important part among the geological operations which change the surface of the earth. Had he been content to state in explicit terms the facts of observation on which he relied, and to put forward tentatively, or at least less dogmatically, the conclusions which he drew from them, his views would not improbably have received the attention to which they would then have been justly entitled. But he submitted no evidence in support of his confident asseverations. He made statements as if they expressed admitted truths, when in reality they were for the most part either disputable or actually contrary to already ascertained fact. On such an unreliable basis his characteristic ardour led him to build a stupendous speculation, in the promulgation of which, besides giving flight to his winged imagination, he was able at the same time to proclaim his own peculiar chemical views and to express once more his scornful dissent from the prevailing chemistry of his day. Tt can hardly be matter for surprise that, as he himself complained, his opinions on these matters met with no serious attention. It is interesting to trace the logical process by which so gifted a genius arrived at conclusions to which his contemporaries would pay no heed, and which his successors have consigned to oblivion. The external crust of the earth, which, in his opinion, might be three or four leagues in thickness, consists of various minerals and rocks almost wholly made up of compound substances. The materials of this crust have undoubtedly been exposed to the manifold agents of geological change, ever since the world began. According to the prevalent opinion in his time (an opinion which has been amply sustained by subsequent research) the elements have a natural tendency to enter into combination, and the general com- pound nature of the constituents of the crust could be cited in favour of the orthodox view. Lamarck, however, had formed a totally different judgment of the matter. His own investigations had led him to conclude that, owing to the operation of the agents of destruction, the tendency in Nature was in exactly the opposite direction, that is, towards the breaking up and simplification rather than to the formation of compound substances. He regarded the surface of the globe as a vast field whereon Nature is ceaselessly at work in destroying every compound and resolving it into its integral constituents. Not that this change is always effected at once, by a complete liberation of the components; it rather comes as the result of successive alteration, the cumulative effect of which is to leave the substances progressively less complex (p. 101). This process of disintegration appeared to him to arise sometimes from an inherent tendency in the material itself to split up into its component ingredients, but more frequently from the action of external provocative influences, such as those of heat, water, and saline solutions. But if such be the normal order of things, how comes it, he asks, that the outer crust of our planet, which, for such a prolonged succession of ages, has been ceaselessly exposed to this destruction and simplification of composite bodies, should nevertheless now A Geological Retrospect of the Year 1802. 1538 consist of substances which are almost entirely compounds? With the confident anticipation that how much soever his contemporaries and their successors might retard the recognition of what he felt assured was a great discovery made by himself, Lamarck announced that there must exist in Nature a certain powerful and ever active cause which, while it counteracts the natural tendency of compound ‘substances to break up into their constituent parts, is ceaselessly at work on its own side in forming new combinations. He triumphantly declared that this potent cause can be none other than the organic action of plant and animal life. Maintaining that the elements could never of themselves have formed the host of ‘compound bodies on the face and within the crust of the globe, he went on to assert that without the operation of life, the ‘ Pouvoir de la Vie,’ not one of these compound bodies could ever have come into existence (p. 106). Not only did he affirm that by the immediate action of vegetation, carbon, bitumen, coal, alumina, potass, clays, iron, and other mineral substances are formed, and that the action of animals gives rise to calcareous material, phosphates, sulphur, nitre, and other compounds (pp. 111, 118, 141, 153), but he claimed that, without exception, all the compound ‘substances in the inorganic world, minerals and rocks alike, are nothing but the remains and débris of once living bodies (p. 115). Protrusions of igneous matter into the terrestrial crust have thus no place in his system. Yet although he believed all amorphous rocks to have been accumulated under water he rejected Werner’s doctrine of an waiversal ocean. The origin of granite, for instance, the explained by a complicated process wherein the essential molecules of the several minerals that constitute the rock are first disintegrated by the action of organisms; these molecules are then transported from the land by rivers into the sea, where they are deposited and come together to form the aggregate granite mass (pp. 142-145). So far from looking upon the granitic core of a mountain-chain as a plutonic intrusion from an inner magma, he regarded it as evidence of the site of a former river-current, by which its materials were built up on the sea-floor during the retreat -of the oceanic waters, and the consequent emergence of the western shores of the land (pp. 145-149). As some rivers flow in tolerably -straight courses for hundreds of miles, he could see no reason why, as the sea retired, they should not have accumulated granitic ridges as long as the longest crystalline core now to be seen in any mountain-chain. Obviously not even the wildest hypothesis of the Freiberg School was more completely a child of the imagination than this extraordinary speculation of the illustrious biologist of ‘Paris.! 1 His speculations on this subject, however, were not all original on the part of Lamarck. Cuvier, in his ‘‘ Discours sur les Révolutions de la Surface du Globe” (3rd ed., 1825, p. 24), alludes to their prevalence, especially in Germany, at least as far back as the beginning of the nineteenth century, and to their recent develop- ment by his French contemporary in the ‘‘ Hydrogéologie’”’ and ‘‘ Philosophie .Zoologique.” (Zo be concluded in our next number.) 164 F. R. Cowper Reed—Corries of Comeragh Mountains. II.— Norres oN THE Corries oF THE ComEeRAGH MovunTaAINs, Co. WATERFORD. By F. R. Cowrrer Resp, M.A., F.G.S. (PLATE XIII.) HE corries and tarns of the Comeragh Mountains have received but scanty attention at the hands of geologists. In the Memoir of the Geological Survey ' dealing with this portion of co. Waterford their position and height are mentioned, and reference is made to some of the glacial phenomena in their immediate neighbourhood, but no connected description of the whole group of corries is given. Kinahan, in his “Geology of Ireland” (1878), pp. 245, 310, refers. briefly to them, and inclines to the view that they were cut out by the action of the sea on the flanks of the mountains, but that the rock-basins which they frequently contain were excavated by small glaciers. The position of the corries, chiefly on the north and east sides of these mountains, as elsewhere in Ireland, is attributed by him to the preservative action of the ice and snow, which would not melt in them so rapidly (owing to their colder aspect) as on the southern and western slopes, where the corries have been obliterated by denudation effected by ordinary subaerial agents. Carvill Lewis ° refers to the glaciation of the Comeragh Mountains in several places, remarking that they ‘show signs of glaciation on their north-east side as high as 1,000 feet, up to which height they are rounded off and drift occurs. Above this they are jagged and contain cwms, glacial lakes, and other evidences of small local glaciers.” The following notes on these interesting corries must be con- sidered to be only of a preliminary nature; a bathymetrical survey of the lakes themselves is necessary to complete their investigation, but possibly this may not be carried out for years owing to the absence of boats on their surface or in the neighbourhood and the difficulty and expense in conveying one to them. Geological Structure of the District. The mountains are entirely composed of Old Red Sandstone forming a wide flattened arch, or rather dome, of which the beds- dip to the north and south respectively into the valleys of the Suir and Dungarvan, while to the west they dip at very low angles so as ultimately to pass under the Carboniferous Limestone in the district of Ballymacarbery. But this uniformity of structure is modified to some extent by small local folds and disturbances in the beds, the axes of which mostly trend east and west in accordance with the general system of folds affecting the Upper Paleozoic rocks of this part of Ireland. The eastern portion of the dome has been removed by denudation, exposing at the foot of the escarpment thus formed the much-worn platform of Ordovician rocks, on which the Old Red Sandstone rests with a very strong unconformity. The Old Red Sandstone in the Comeraghs is estimated* to reach 1 Mem. Geol. Sury. Ireland, Explan. Sheets 167, 168, ete., 1865, pp. 6, 7, 80. ? Carvill Lewis: ‘‘ The Glacial Geology of Great Britain and Ireland,” 1894,. pp- 103, 133, 164. 3 Mem. Geol. Surv. Ireland, Explan. Sheets 167, 168, etc., p. 14. F. R. Cowper Reed—Corries of Comeragh Mountains. 155 ‘a total thickness of 3,200 feet, and consists of a locally developed basal breccia followed by about 1,000 feet of brownish-red conglomerate of various degrees of coarseness; and this is succeeded by reddish- brown shales, sandstones, grits, and strong conglomerates, with many white quartz pebbles, reaching a thickness of about 2,200 feet. The jointing of the Old Red Sandstone rocks, both conglomerates and sandstones, is strikingly complete and well developed’; and the presence of these divisional planes and lines of weakness has an intimate connection with the production and preservation of the precipitous walls of the corries. The alternation of hard and soft beds of rock is clearly brought out by weathering in the cliff-faces of some of the latter, such as Coumshingaun, and results in the formation of successive small vertical cliffs or scars alternating with benches and talus slopes, expressing the vertical heterogeneity in the profile. Orography of the District. The Comeragh Mountains form a mass of high ground at the western end of co. Waterford, their main axis running nearly north and south; they rise to a maximum height of 2,597 feet above sea- level, and break off suddenly towards the east in a more or less regular escarpment, the summit of which is in most places over 2,000 feet high, but it sinks down gradually and loses its character to the north and south. The northern part of the range is sometimes known as the Reeks of Glenpatrick, and joins on to the line of lower rounded hills bordering the south side of the River Suir. The platform of older rocks which stretches away to the east with a gently undulating surface from the foot of the mountains is known as the plateau of Rathgormuck, and has an altitude of only 300-500: feet above the sea. On the west side the whole mass of the Comeragh Mountains is separated from the Knockmealdown Mountains by the long pass or valley of Ballynamult, which runs southward from the valley of the Suir. Behind the escarpment the Comeragh Mountains are deeply trenched by the valley of the Nier, which runs in a westerly direction so as almost to bisect them. This river, which ultimately joins the Suir just east of Newcastle, drains the greater portion of the western slopes and receives several tributary streams, some of which flow down from the cirque-headed valleys on its south side. The northern flanks of the mountains shed a few short unimportant streams direct into the Suir; and the south-west slopes are drained by the Colligan, which flows south into the sea at Dungarvan. The eastern escarpment, traced from its northern end, runs at first south-east at the foot of the Reeks, but at a point just south of Knockanaffrin Mountain it turns to the east, and continues in this direction for over one mile, forming a large embayment, at the bend of which is the important gap and pass into the head of the Nier Valley. This pass makes a conspicuous dip in the fairly uniform summit-line of the mountains, being only 1,500 feet above 1 Haughton, ‘‘On the Physical Structure of the O.R.S. of Co. Waterford’’ : Trans. Roy. Soc. Dublin, 1858, pp. 333-348. 156 F. R. Cowper Reed—Corries of Comeragh Mountains. sea-level, while on each side of it the top of the escarpment is over 2,000 feet high. A little north of Coumshingaun the escarpment again bends round and runs south for nearly three miles to the Mahon River. In addition to the short, steep, grassy spurs which slope down from the face of the escarpment to the plain, and between which lie the rock-walled corries, there is an extensive promontory of hill ground, composed of Old Red Sandstone and connected with the main mass by a low isthmus; it projects eastwards nearly opposite Coumshingaun for a distance of about four miles across the Lower Paleozoic platform, and rises towards its extremity into the prominent Slievenaman J 1000" 500" R. Sutn namult valle Reduced to a scale 5 miles to 1 inch. Fic. 1.—Contour-Map of the Comeragh Mountains and neighbourhood. 1, Lough More; 2, Coumduala Lough; 3, Coumgorra Loughs ; 4, Crotty’s Lough ; 5, Coumshingaun Lough; 6, Comeragh Loughs; 7, Coumstilloge Loughs. F. R. Cowper Reed—Corries of Comeragh Mountains. 157 elevation known as Croghaun Hill, nearly 1,300 feet high. The eastern face of the Comeraghs is drained by many small streams, some of which are supplied by the tarns in the corries. North of the Croghaun spur these streams flow in a general eastward direction into the Clodiagh, which falls into the Suir, but south of Croghaun the streams run south-east to form the rivers Mahon and Tay, which enter the sea at Bonmahon and Stradbally respectively. From the above description of the waterways it is seen that the Comeraghs give rise to a complete and independent drainage system on all sides, and form a local centre, as they are supposed to have done for the ice during the later stages of the Glacial Period.’ DISTRIBUTION AND CHARACTERS OF THE CoORRIES AND TARNS. The corries in the Comeraghs fall into two groups, one of which lies along the steep eastern face of the mountains and the other along the south side of the Nier valley. In the former group they have mostly the character of mere niches in the escarpment, while in the latter group they attain nearly the dignity of short valleys. All are alike characterised by steep mural precipices and by their floor lying at some height above that of the thalweg of the main valley or the base of the escarpment, so that they possess the appearance of ‘hanging valleys.’ In the eastern series of corries not all have received names ; only those which contain lakes are marked on the map with separate designations, but there exist several others which deserve notice. We may first enumerate those which contain lakes, commencing at the northern end, and then proceed to describe them all in detail. I (a). Corries and their lakes in the Reeks of Glenpatrick. 1. Lough More. 2. Coumduala Lough. (b). South of the great embayment. 3. Coumgorra Lough. 4. Crotty’s Lough. 5. Coumshingaun Lough. II (c). Corries and their lakes on the south side of the Ner Valley. 6. Comeragh Loughs. 7. Coumstilloge Loughs. The Reeks of Glenpatrick have only two corries occupied by lakes on their eastern face, but there are several other corries on the escarpment, the floors of which are occupied with great sloping heaps of talus from the cliffs above. A lake may have previously existed in them, but has been overwhelmed and filled up by the accumulation of this débris. In one case the absence of a barrier of moraine or scree material across the mouth, such as is found in all the others which hold a tarn, may account for this deficiency. 1 Mem. Geol. Sury. Ireland, Explan. Sheets 167, 168, etc., p. 80. Kinahan; Geol. of Ireland, p. 245. Hull: Phys. Geol. Geogr. Ireland, 1878, pp. 103, 263. 158 F. R. Cowper Reed—Corries of Comeragh Mountains. ‘There is one such lakeless corrie on the north of Knockanaffrin, and like all the corries on the Reeks it is shallow and wide-mouthed, con- sisting simply of a slightly curved amphitheatre of cliffs descending precipitously to a gently inclined floor, which from the mouth slopes more steeply to the plain below. The small streams which issue from these tarnless corries north of Knockanaffrin run down over the surface of the ground in shallow channels to join the Glasha River, which enters the Suir near Gurteen. The two lakes, known as Lough More and Coumduala Lough, lie under the higher part of the escarpment, the former on the north side of Knockanaffrin and the latter on the south side. The altitude of Lough More is 1,518 feet, and it is situated in a wide, shallow alcove with the cliffs rising 550 feet above it. In size it only measures about 200 yards in length, and the stream issuing from it runs down to join the Clodiagh. A dam of morainic material rises about 60 feet above the water’s level and holds up the lake. WIN lip bape i Croltys Foci 2/24-" Scale: £4 inches to 1 mile. Fie. 2.—Sketch-map of Coumgorra. Fic. 3.—Sketch-map of Crotty’s Lough Corrie. Coumduala Lough lies at an altitude of 1,535 feet in a shallow amphitheatre where the escarpment is nearly 2,100 feet high ; screes cover the foot of the cliffs, and the lake, which is held up by a dam on the north-east, has its length (250 yards) parallel to the trend of the escarpment, and therefore across the mouth of the corrie. Its overflow is conducted down to the Clodiagh by a stream from its south-east corner. From Knockanaffrin the escarpment decreases in height towards the Gap and curves round in an irregular semicircular line of cliffs and scars so as to form a large broken corrie, but without any definite floor, as the slope at the base of the cliffs is covered with talus and morainic heaps. One of the head-streams of the Clodiagh arises in this amphitheatre. None of the foregoing corries or tarns are comparable in importance to the large ones south of the Gap which have now to be described, F. R. Cowper Reed—Corries of Comeragh Mountains. 159 and comprise those known as Coumgorra, Crotty’s Lough, and Coumshingaun. All these contain lakes, and are situated close together. Thus, Coumgorra is only 500 yards distant from Crotty’s Lough on the northward - facing part of the escarpment; and Coumshingaun, which looks west, lies only 650 yards south of Orotty’s, while the divide separating the head of Coumgorra from Coumshingaun is not much over 700 yards wide. ‘This triangular group of corries affords the most striking features of their class, and therefore merits special attention. The corrie nearest the Gap is known as Coumgorra, and contains three lakes at successive levels; the two lower ones are merely expansions of the stream behind and between heaps of morainic material. This stream, which connects the three lakes, flows from 2200° Vertical section of Coumgorra 1596 ° Lake (456° pe Veriical section of Crottys Lough. Fie. 5. Vertical scale: 2,000 feet to 1 inch. Horizontal scale: 1,760 feet to 1 inch. the mouth of the corrie in a north-easterly direction as the River Douglas to join the Clodiagh at Ross Bridge. The corrie itself is of Jarge size, and opens northwards ; it has an irregular shape, and on investigation is found to be composed of two contiguous and partly confluent amphitheatres, a weathered and semi-detached pinnacle of vock marking the point of intersection of the two curved lines of cliffs. The outer amphitheatre forms the western side of this composite corrie and is not deeply cut back, but the cliffs encircling it are higher and more precipitous, rising about 1,000 feet above their talus-strewn base, and more than 2,500 feet above sea-level. The two lower lakes lie in this outer corrie, but not close under its cliffs nor at the same level. Their origin is obvious, 160 F. R. Cowper Reed—Corries of Comeragh Mountains. the stream from the uppermost and inner lake having expanded into irregular small sheets of water in its attempts to escape between the confused mounds of moraine which obstructed its direct course, and through which it has not yet been able to establish a regular curve of erosion by cutting out a channel for itself. The inner corrie of Coumgorra faces north-west, and is likewise surrounded by bare craggy precipices with a fairly even skyline; the tarn lies at a height of 1,818 feet above the sea, and the mountain behind it has an altitude of over 2,400 feet. This tarn—Coumgorra Lough proper—measures about 180 yards long by 120 yards wide, and is held up by a regular grass-covered bank of morainic material with such a straight course and even top as to present a most artificial appearance. ‘The water escapes from the lake underground at the western corner, percolating through the loose material of the dam and flowing thence down to the middle lake. This lakelet lies at a level of 1,671 feet between somewhat irregularly disposed morainic mounds, which do not unite to form a single dam. The lowest lake lies about 100 feet lower down, and is of the same nature and origin; the mounds which hold the water back rise 50-100 feet above its level, and rest on the corrie-floor at its very mouth. Beyond and outside them the steeper slopes of the mountain descend at once for a continuous 500-600 feet till we reach another more or less level platform or broad shelf, formed by another but more evenly distributed mass of moraine, extending outwards in a roughly crescentic fashion for some distance over the plain, at the base to which it descends by a short steep face. Original irregularity of accumulation and subsequent denudation have obscured to some extent the outlines of this lower moraine, but its main features can be distinctly traced. There is: nothing to indicate the existence of a rock-basin in the case of any of these Coumgorra tarns, and the stream from them runs either over or through morainic material in each case. The small erosive power of the stream, owing to the pure nature of its water, is noticeable. The moraines have the usual character of those of valley glaciers, and the large proportion of big angular blocks in their composition and on their uneven and scantily-clad surface gives the ground which they cover a wild and rugged appearance. In size the composite corrie of Coumgorra measures about 1,100 yards from its mouth to its head, and has a width across its entrance of rather over 900 yards. The next corrie to the east is that containing Crotty’s Lough, which is an irregularly-shaped piece of water with its longest axis measuring about 350 yards and lying transverse to the mouth of the corrie. The level of the tarn is marked as 1,396 feet above the sea. The corrie faces north-east, and is formed by lofty cliffs on the west, south, and east sides. On the western side the precipice is vertical for several hundred feet in its upper part, and its top is over 1,000 feet above the water’s edge. Steep grass-clad screes slope three- -quarters of the way up the face of the cliffs at the head of the lake ; and at the south-east. corner two prominent bare rocky ‘crags GEoL. MAG. 1906. Dec. V, Vol. III, Pl. XIII. Corries in the Comeragh Mountains. Dr. F. H. Hatch—Geological History of South Africa. 161 rise up above the general rim of cliffs, one of which contains Crotty’s Cave, and is a landmark for many miles. The eastern side of the corrie is mostly formed by a less precipitous spur from the mountain-side. The mouth is partially blocked by a conspicuous rounded hill strewn with large boulders and rising about 100 feet above the level of the water. On its outer or northern side this hill descends steeply for about 450 feet to a broad, roughly semicircular shelf with fairly level surface, probably representing an old moraine. The latter has an abrupt edge which slopes down suddenly to the plain about 300 feet below. On each side of the rounded hill at the mouth of the corrie there is a possible outlet for the waters of the lake; the one on the north- west side would be over solid rock, and a rise of five or six feet in the level of the water would cause the outflow to be by this channel. On the other or eastern side the rounded hill is joined to the mountain spur by a ridge of morainic material which blocks up the wider and more natural outlet, and the lake discharges itself at this point by the water percolating through the dam and issuing on its further side in a series of springs which feed the swamps and give rise to the streamlet running down a depression in a north-easterly direction. It is noticeable that the rocky lip of the lake on the west is lower than the top of the dam on the east, but the outflow of the lake is nevertheless at a lower level on the other side of the median hill, which indeed appears to consist entirely of morainic material and to represent merely an unusually large and regular morainic mound. No solid rock is visible in its composition above the level of the lake, and there is no direct evidence that we have to deal with a true rock-basin in this instance. (Zo be continued.) IjI].—Tue Geotocican History or Soutn Arrica.! By Dr. F. H. Harcu, F.G.S., M.I.C.E., President of the Geological Society of South Africa. (Concluded from the March Number, p. 104.) 3. Geological History of the Rocks. FTER the granites, gneisses, schists, and sediments which make up the Swaziland System had been elevated to form a continental area extending over the northern and western portions of South Africa, denudation began, and the material thus produced was carried to the sea to form the Witwatersrand Beds. The nature of these sediments —they consist of conglomerates, grits, and shales— indicates a marine period with shallow-water conditions, which continued almost uninterruptedly during their deposition. They were accumulated first on a sinking, and then on a rising sea bottom, for the lower beds are composed largely of mud and fine sand, conglomerates only becoming abundant in the upper beds, which were formed in the later portion of the period when the 1 Presidential Address delivered by Dr, F. H. Hatch to the Geological Society of South Africa, 29th January, 1906. DECADE V.—VOL. III.—NO. IV. 11 162 Dr. F. H. Hatch—Geological History of South Africa. sea had become sufficiently shallow to allow of the accumulation of shingle and gravel. There is evidence in the Southern Transvaal that the land from which the sediments were mainly derived lay to the west, the sea to the east, for the lower Witwatersrand Beds, which consist solely of mudstones and fine sandstones in the east, gradually develop conglomerates with a decreasing amount of shale towards the west. The northern shore-line of the Witwatersrand sea probably did not extend north of the 25th parallel of latitude, for in the Northern Transvaal we find the Waterberg Sandstone resting directly on the granites and gneisses of the Swaziland System, while in Southern Rhodesia, north of Bulawayo, the oldest deposits resting on these rocks are the Sijarira sandstones,! which immediately underlie the Matobola Coal-measures, in which fossils indicating a Permo- Carboniferous age have been found. After the close of the Witwatersrand period, which was brought about by the final elevation of these beds above sea-level, they in their turn became exposed to the disintegrating forces of denudation, the resultant débris being transported and spread out by the heavy flood waters of torrential rivers, since we find the Ventersdorp period ushered in by the accumulation of coarse conglomerates and boulder beds, in which occur fragments of such characteristic beds of the preceding formation as Hospital Hill Slate and the auriferous conglomerates of the Upper Witwatersrand Series. This denudation produced the second break in the succession, marked as Unconformity No. II in the scheme given on page 98. The Ventersdorp period is particularly marked by volcanic manifestations, vast thicknesses of basic and acid lavas, volcanic breccia and tuffs having been accumulated, probably on a land surface. Before the next submergence, that of the Potchefstroom period, the vast piles of volcanic accumulations, together with the boulder beds and coarse conglomerates of the Ventersdorp System, were long exposed to denudation, as there is a break (Unconformity No. III) between this and the succeeding system, the lowest member of which, the Black Reef Series, is found lying uncon- formably on every older formation down to the granite and schists of the Swaziland System. At some time before the deposition of the Black Reef and Dolomite Series, the Witwatersrand Beds had been subjected to a folding movement, as the latter are found bent into gentle synclines and anticlines, on the denuded remnants of which the former lie undisturbed.2 The Potchefstroom System consists of three members: a small development of sandstone at the bottom with a basal conglomerate, dolomitic limestone and shales in the middle, and a great thickness of shales and sandstones on the top. This succession indicates a comparatively rapid sub- mergence, continued until clear water conditions were reached, in which the accumulation of calcareous sediments became possible. 1A. J.C. Molyneux: Q.J.G.S., vol. lix (1903), p. 288. 2 F. H. Hatch, ‘‘ The Extension of the Witwatersrand Beds eastward under the Dolomite,”’ etc. : loc. cit., p. 68. a Dr. F. H, Hatch—Geological History of South Africa. 163 The period during which the muds and sands now forming the Pretoria Series were deposited was probably one of slow oscillation between rising and sinking, the conditions representing on the whole a shallow-water phase. The shore-line of a bay-like portion of the sea in which the sediments of the Potchefstroom formation were deposited is well marked in the Transvaal by the outcrop of the Black Reef Quartzite, as may be seen by consulting a geological map of the Transvaal, but some allowance must of course be made for subsequent denudation, especially in the Lydenburg district. The main sea, however, extended over the southern portion of Bechuanaland and Griqualand, between the Vaal and Orange Rivers. The final emergence of the rocks of the Potchefstroom System produced, by denudation, another great break in the succession, namely, the unconformity (No. IV) which separates the Waterberg from the Potchefstroom System. During the interval represented by this break, the beds of the latter were tilted, flexured, and dislocated. The resultant land surface furnished the material for the building up of the Waterberg formation. The basal con- glomerates and breccias of the latter were first formed, namely, during the subsiding period. From the fact, to which attention has been drawn by Mr. Holmes, that pebbles of red felsite are found in these basal conglomerates,’ it is probable that an eruption of acid lavas began while the Potchefstroom strata were being upraised; this igneous activity was probably long continued, for quite recently Mr. Mellor* has described in the lowest portion of the Waterberg Series at Rhenosterkop the occurrence of fragmental beds consisting for the most part of igneous material, from which he draws the conclusion that this period was marked by vigorous contemporaneous volcanic action, and he makes an _ interesting comparison with the conditions that obtained at the commencement of the Old Red Sandstone period in Scotland. The character of the Waterberg rocks, consisting as they do largely of conglomerates, grits, and coarse sandstones, indicates shallow-water conditions in a slowly subsiding area. The constant occurrence of false bedding points to rapid sedimentation in shallow waters affected by strong and variable currents.? The pebbles of the basal conglomerate consist largely of quartzite derived from the Pretoria Beds, and there is evidence that the Waterberg sediments were deposited against an old land surface of the Pretoria rocks, which underwent denudation to supply the necessary material. The present distribution of the Pretoria Beds along the southern margin of the Waterberg Sandstone probably marks the shore-line of the sea or lake in which the latter was laid down. This sea extended over the greater part of the Northern 1G. G. Holmes, ‘‘ Some Notes on the Geology of the Northern Transvaal” : Trans. Geol. Soc. §. Afr., vol. vii (1904), pp. 55-56. ‘‘The Geology of a part of the Rustenburg District ’’: Trans. Geol. Soc. 8. Afr., vol. viii (1905), p. 6. 2 KE. T. Mellor, ‘‘ Volcanic Action in the Waterberg Formation’’: Trans. Geol. Soc. 8. Afr., vol. viii (1905), p. 38. 3 E. T. Mellor: Transvaal Geol. Surv. Rep., 1903, p. 17. 164 Dr. F. H. Hatch—Geological History of South Africa. Transvaal, and probably included a portion of Southern Rhodesia ; it may have been landlocked, for the facts that the Waterberg formation has been found resting on an uneven floor, and that near the base very coarse irregular conglomerates’ are met with, seem to militate against this formation being a true marine deposit. The Cape Colony representative of the Waterberg Sandstone, namely, the Table Mountain Sandstone, also consists of sandstone, but with less conglomerate. Conglomerates, although scarce, however, do occur, and Rogers has described in the Pakhuis Pass, near Clanwilliam, the occurrence of ice-scratched pebbles which appear to have come from a glaciated region, and to have been carried to their present site by the agency of floating ice.? From an increase in the degree of coarseness of the sediments towards the west, and the greater frequency of conglomerates in the Piquetberg division and the Olifants River Mountains, Rogers argues that their source must have lain in that direction, and that the sediments were accumulated at no great distance and in shallow water. In his view the Table Mountain Sandstone is probably of fluviatile origin.® The Table Mountain Sandstone is followed conformably at the Cape by the Bokkeveld Beds, the character of which points to a continuance of the subsiding phase. The fossil remains indicate marine conditions, although the frequent occurrence of false bedding in the sandstones precludes the possibility of very deep waters. The fossil fauna of the Bokkeveld Beds shows that they are homotaxial with the Devonian System, but whether Upper, Middle, or Lower has not yet been decided. The upper beds of the Bokkeveld and the succeeding Witteberg Beds indicate a change to lacustrine or finviatile conditions, the beds consisting of mudstones and sandstones which, with the exception of a few plant remains, are barren of organisms. It is possible, as suggested by Mr. Rogers,‘ that at about the middle of the Bokkeveld period open communication with the sea may have been again cut off, deposition subsequently taking place by fluviatile agencies in inland seas. This would account for the absence of marine organisms in these beds. At the Cape the Witteberg Beds are followed without a break by the shales forming the lowest beds of the Dwyka Series. Northwards, however, the Witteberg and Bokkeveld Beds gradually thin out, and the Dwyka Series finally rests unconformably on the Table Mountain Sandstone. From this the deduction can be made that owing to the elevation of the beds above sea-level, they became subject to denudation before the commencement of the Dwyka epoch, and it is even possible that still further north denudation may have commenced before the Witteberg epoch, so that the latter series was never deposited in 1K. T. Mellor, ‘‘The Waterberg Sandstone Formation’: Trans. Geol. Soe. S. Afr., vol. vii (1904), p. 40. Mr. Mellor instances the occurrence of boulders ranging up to 8 feet in diameter. These must have been transported by streams of a torrential character. 2 A. W. Rogers, ‘‘ The Glacial Conglomerate in the Table Mountain Series near Clanwilliam’’: Trans. 8. Afr. Phil. Soc., vol. xvi (1905), p. 1. 3 A. W. Rogers: ‘‘The Geology of South Africa,’ p. 395. 4 “Geology of the Cape Colony,” p. 396. Dr. F. H. Hatch—Geological History of South Africa. 165 ‘these northern regions; and in the Transvaal it is most likely that even the Bokkeveld Series was never represented. During the accumulation of the Dwyka Series the northern part of South Africa was covered with ice, for it is now generally admitted that the Dwyka Conglomerate has been formed of rock fragments, boulders, and mud, which have been carried towards their present site by glaciers moving from a northern mountainous country southward. That the highest portions of these mountains were probably situated in the Northern Transvaal somewhere about the present Waterberg district, is indicated by the distribution of the glacial conglomerate. The Dwyka Series as well as the rest of the Karroo rocks appears to have accumulated in a great inland sea which occupied practically the whole of Central South Africa as at present constituted. The southern shore-line of this vast lake extended east and west along the northern margin of the present coast ranges of Southern Cape Colony. ‘To the east it passed into the present Indian Ocean some- where about the Gualana River, returning at Port St. John, whence it stretched north-eastward parallel to the present coast of Natal, the north-western boundary extending roughly along the present course of the Vaal River as far as Vereeniging. The fossil evidence points to fresh-water, or at least to brackish conditions, and the frequent occurrence of false bedding, ripple- marks, sun - cracks, worm burrows, etc., indicates that the water could not have been deep. The Dwyka Conglomerate was deposited partly in this lake by the agency of floating ice; partly it consists of ancient moraines the accumulation of which slowly followed the retreating ice north- wards. In conformity with this twofold mode of origin, there are two facies of the Dwyka Series: a northern, lying unconformably on an uneven surface (often grooved and polished) of the older rocks, and a southern, resting conformably on the uppermost member of the Cape System. In the Transvaal the Dwyka covering has preserved interesting features of the pre-Karroo land surface. Thus Mr. Mellor’ considers that the valleys of the Hlands River, Bronkhorstspruit, and the Wilge River are of pre-Karroo origin. At the beginning of Karroo times they became filled with the conglomerate, and have in recent times been re-excavated. The coal deposits, which at Vereeniging and elsewhere in the Southern Transvaal and at Dundee and Newcastle in Natal are found in the Ecca Beds immediately above the Dwyka Conglomerate, show that a luxuriant tropical vegetation flourished in the Ecca epoch; while the fact, first pointed out by E. J. Dunn,? that seams of breccia of almost identical character with the Dwyka are interbedded with the coal at Vereeniging, seems to indicate that glaciers were still In existence while the coal beds were being deposited. Professor Edgeworth David * has described a similar occurrence in New South 1K. T. Mellor: Transvaal Geol. Surv. Rep., 1908, p. 20. _ 2 E. J. Dunn, ‘ Notes on the Dwyka Coal-measures”?: Trans. 8. Afr. Phil. Soc., vol. xi (1900), p. 67. 3 Edgeworth David, ‘‘Evidences of Glacial Action in Australia in Permo- ‘Carboniferous Time”: Q.J G.S., vol. lii (1896), p. 289. 166 Dr. F. H. Hatch—Geological History of South Africa. Wales, where a group of Coal-measures over 230 feet thick and comprising from 20 to 40 feet of coal is sandwiched in between the erratic bearing horizon of the ‘ Lower Marine Series’ and the similar horizon of the Upper Marine Series. There appears to be indicated in these facts a recurrence of a glacial epoch separated by a milder interglacial period. Professor Penck, however, to whom I showed specimens of these later breccias in borehole cores from the Vereeniging Coalfield, thought they probably represented a rewash or remanié of the true Dwyka. With regard to the age of the Transvaal coal, the occurrence of Sigillaria Brardi at Vereeniging supplies a link with Europe, and on this evidence Seward ! assigns the beds to the Permo-Carboniferous period, and suggests that the commingling of Sigillaria species with the Glossopteris flora indicates. an overlapping of two distinct botanical provinces. A recurrence of the conditions suitable for the formation of coal deposits took place at a much later epoch in the Karroo period, namely, at the beginning of Stormberg times (Molteno Beds). Between the two horizons there are some 7,000 feet of strata in the geological column, 5,000 feet of which are made up of the Beaufort Series, which requires no special mention here, except for the abundant occurrence in it of the remarkable labyrinthodont and. dinosaur remains. The bones of these animals must have been washed into the lake by rivers. At the top of the Stormberg Series, and consequently occupying the highest position in the system, are the basic lavas and ash-beds of the Volcanic Group. The interstratification of ash-beds and lava- flows with sandstone points to some subaqueous eruption; but the bulk of the later flows were subaerial, and the accumulation of such a vast pile of volcanic material—it is some 4,000 feet thick— determined the watershed of the Drakensberg as it exists to-day in Basutoland and the Eastern Province of Cape Colony. Many of the vents by which the eruptions took place have been found,? cutting through the Cave Sandstone, by the Cape Geological Survey ; but Mr. Schwarz is of the opinion that fissure eruption also played a part in the formation of the volcanic beds. It is interesting to note that the remarkable series of lavas occupying the so-called Springbok Flats in the Transvaal, and known as the Bushveld Amygdaloid, has been found by the Transvaal Survey to overlie sandstones which are considered to be of Karroo age, and has been provisionally referred to the Stormberg epoch. There is certainly a remarkable resemblance in the 1 A. C. Seward: Q.J.G.S., 1897, p. 322. . 2 An interesting account of the geological history of these eruptions is given by Mr. du Toit in a paper on ‘‘ The Forming of the Drakensberg’’: Trans. S. Afr. Phil. Soc., vol. xvi, pt. 1 (1905), p. 65. See also ‘* Report on part of the Matatiele- Division, with an Account of the Petrography of the Volcanic Rocks,’’ by E. H. L. Schwarz: Geol. Comm. Rep. for 1902, p. 11; Capetown, 1903. Also ‘ Geological Survey of Elliott and Xalanga,’’ by A. L. du Toit: Geol. Comm. Rep. for 1903, p- 109; Cape Town, 1904. 3 E. T. Mellor: Transvaal Geol. Surv. Rep., 1904, p. 31; Pretoria, 1905. Also Trans. Geol. Soc. S. Afr., vol. viii (1905), p. 87. Dr. F. H. Hatch—Geological History of South Africa. 167 petrographical habit of these amygdaloids to the lavas of the Volcanic Group of the Drakensberg and Malutiberg. In this connection, the discovery by the Survey of a ‘pipe amygdaloid’ in the Bushveld lavas, similar to the characteristic rock of the Stormberg Volcanic Group, is noteworthy. . The dolerite intrusions, which are so widely distributed in the Karroo rocks, and form such a striking feature in their scenery, belong to a period: somewhat posterior to the volcanic eruptions of the Stormberg epoch; their late limit is fixed by the fact that boulders of the typical dolerite have been found in the Umtamvuna (Upper Cretaceous) rocks of the Pondoland coast.'!' Intermediate in age between the Stormberg volcanoes and the period of intrusion of the Karroo dolerites, are the volcanic pipes so well known on account of the diamond being a constituent of their breccia filling at Kimberley and in the Transvaal. The facts on which this argument is based are as follows :—The Stormberg lavas are occasionally penetrated by dykes,” which probably belong to the Karroo dolerites, while Messrs. Rogers and Du Toit * have shown that the Sutherland pipes, which are analogous to the diamond-bearing deposits, except that they do not yield diamonds, are of later age than the latter. The exact period at which the Cape Formation and the overlying Karroo Beds were folded to form the great mountain ranges of the Southern Cape (the Zwarteberg, Langeberg, etc.) cannot be fixed, but it was after the deposition of the Lower Karroo Beds, as these are involved in the folding, and before the deposition of the Uitenhage Beds, since the latter lie undisturbed on the folded Cape Formation. To summarise: we have in South Africa evidence of the former existence of at least three periods during which the greater portion of South Africa was elevated above sea-level, besides the one we live in, which has endured since Karroo times. The first of these is indicated by the break in the succession below the Witwatersrand System ;. the second by the volcanic and fluviatile deposits of the Ventersdorp System, and the unconformity between the latter and the succeeding Potchefstroom System; and the third by the break between the Potchefstroom and the Waterberg Sandstone. Between these must have intervened three periods, during which a large portion of South Africa was submerged, and the marine and littoral sediments of the Witwatersrand, the Potchefstroom, and the Cape Systems were deposited; and a long period of fresh-water sedi- mentation during which the Karroo rocks were accumulated by the agency of vast river systems discharging into great lakes. The coastal deposits (the Uitenhage and Umtamvuna Series), which are marine deposits of a later (Cretaceous) period, are not considered here, as they play only an insignificant part in the geology of South Africa; and I have limited myself to the close of the Karroo period. 1 Rogers & Schwarz: Ann. Rep. Geol. Comm., 1901, pp. 25-46 ; Capetown, 1902. 2 A. C. du Toit, ‘‘ The Forming of the Drakensberg’: Trans. 8. Afr. Phil. Soc., vol. xvi (1905), p. 67. 3 Rogers & Du Toit, ‘‘The Sutherland Volcanic Pipes and their Relationship to other Vents in South Africa’’; Trans, S. Afr, Phil. Soc., vol. xv (1901), p. 61. 168 Dr. F. H. Hatch—Geological History of South Africa. It is not likely that at any period since its first upheaval the whole of South Africa has been submerged ; indeed, there is evidence that the northern region remained uncovered and subject to erosion up to the commencement of Karroo times. On the other hand, it is unlikely that the continent has always had its present limits; the similarity of the remarkable Damuda-Talchir flora of India, the Newcastle flora of Australia, and the Lower Karroo flora of South Africa indicates that in Permo-Carboniferous times South Africa was probably united to India and Australia to form one great continent, which Suess! has named Gondwanaland. Blanford? even suggests that in Mesozoic times South Africa was also con- nected with South America, so that “a girdle of land may have extended round nearly three-quarters of the earth’s circumference,” from Peru to New Zealand. Volcanoes have played a great role in the geological history of South Africa, and the traces of this igneous activity survive in the form of lavas, with or without volcanic tuffs and breccias, or in the various forms of intrusive igneous material (laccolites, sills, dykes, etce.), or again as volcanic necks and ‘pipes.’ There are at least five distinct periods in which South Africa has been the theatre of intense igneous activity, and the ages of these may be arranged. as follows: — 1. Between the close of the Witwatersrand and the commence- ment of the Potchefstroom periods, the period of the eruption of the Ventersdorp lavas, tuffs, and breccias. 2. A period commencing after the close of Potchefstroom, and extending into the early Waterberg times, in which the intrusion and eruption of the Red Granite and associated felsite took place. 3. At the close of the Stormberg epoch, eruption of the Stormberg lavas. 4. Between the close of the Karroo period and the commence- ment of the Umtamvuna (Upper Cretaceous) epoch, intrusion of the dolerite dykes and sills. 5. After the intrusion of the dolerites, formation of the pipe breccias. With this summary I must bring my account of the geological history of South Africa to a close, although I have but touched the fringe of the subject. Much remains to be discovered before the secrets of the past can be completely deciphered, and it must be remembered that geology in South Africa is still young. It shows, however, a vigorous growth for all its youth, and I am convinced that in the next few years great progress and many new discoveries will be made. In this progress the Geological Society of South Africa will doubtless have a large share, and uphold or increase the high standing it has already won. 1 “Das Antlitz der Erde,’’ vol. i, p. 768; Vienna, 1885. 2 W.T. Blanford: Presidential Address, Proc. Geol. Soc., vol. xlvi (1890), p. 106. ORDER OF SUPERPOSITION OF THE STRATIFIED Rocks oF Sourn AFRICA. a A PE BE SE EES ES ES ES EE EE ET EvuRoPEAN SouTHERN aiken ag QUIVALENTS. Carr Cotony. ‘ Volcanic Group. Ru ATIC Stormberg Cane uel kone: Missing : ©) Red Beds. pki Karroo Molteno Beds. | / PERMo- System. ) Beaufort Sie 6 Missing. CaRBOoNI- FEROUS... S50 \Ecca and Dwyka ... ... |= Ecca and Dwyka. (Unconformity No. V.) Ca Witteberge ... se ae Missing. DEVONIAN... S ne Bokkeveld ... nae are Missing. System. | Table Mountain Sandstone = Waterberg Sandstone. (Unconformity No. IV.) Potchef- Pretoria Beds. stroom Dolomite Series. System. { Black Reef Series. (Unconformity No. III.) Vontere Boulder Beds, Volcanic alg Breccias, Kliprivers- alae be berg Amyedaloid, ete. Sy Elsburg Conglomerates. (Unconformity No. IT.) Watmateree Upper Witwatersrand sand Beds Ren Lower Witwatersrand Ble e Beds. (Unconformity No. I.) ARCH MAN. Malmesbury Series. = Swaziland System. Note.—This slip is intended to correct the Table given in Dr. F. H. Hatch’s Address, Part I, p- 98, in the March number, 1906, in which, by an error, the Devonian formation was made to embrace with a bracket ad/ the older Transvaal rocks. —Epir. Grou. Mae. ’ co 7 + j ; , | he ‘ P) 7 4 lee, a ? ” 7 ard _ 7 aa -_ i > a 7 \ 4 \ Pendlétony 2S Fig.1. Scale of Miles fo} 1 2 3 u b ° Stockport Fie. 1.—Isoseismal lines of Pendleton Earth-shake, Nov. 25th, 1905. The earth-shake of November 25th, 1905, was strong enough to be noticed in many besides local newspapers, and was investigated without delay. The materials for its study are therefore abundant, the following account being based on 139 records from 46 places, and on negative records from 4 places. 1 Grou. Mac., Dec. IV, Vol. VII (1900), p. 175; Dec. IV, Vol. VIII (1901), p- 361. Dr. C. Davison—The Pendleton Earth-shake. 173 The shock occurred at 3.42 a.m., the centre of the disturbed area being # mile north of the centre of Pendleton (in lat. 58° 29-6’ N., long. 2° 15:8’ W.). At this place the intensity of the shock was 7, ‘and not much below 8, for there was some slight damage done, several chimney-pots and one chimney-stack being thrown down. On the accompanying map (Fig. 1, which is bounded by the parallels of 58° 37’ and 53° 23’ N. lat. and by the meridians of 2° 4’ and 2° 29’ W. long.) four isoseismals are shown, corresponding to intensities 7 to 4. The isoseismal 7 is 3 miles long, 1# miles wide, and 4 square miles in area, but, towards the east, the curve may not be quite accurately drawn. The next isoseismal, of intensity 6, is 6 miles long, 44 miles wide, and contains 21 square miles; the isoseismal 5 is 94 miles long, 74 miles wide, and 56 square miles in area; while the isoseismal 4, which bounds the disturbed area, is 154 miles long, 12 miles wide, and includes an area of 144 square miles. The longer axes of the isoseismal lines are parallel or nearly so, and run from N. 37° W. to 8. 37° H. The distances between the isoseismals are approximately the same on both sides of the longer axes. The shock was brief in all parts of the disturbed area, the average of 11 estimates of the duration being 24 seconds. It consisted of a few prominent vibrations, quick-period tremors having been apparently absent. The sound-area, which is bounded by the dotted line on the map, is 10? miles long, 81 miles wide, and contains 70 square miles. It includes the whole of the isoseismal 5, but falls short of the isoseismal 4 in all directions. The sound was heard by 75 per cent. of the observers. By 14 per cent. of these it was compared to passing traction engines, etc, by 13 per cent. to thunder, by 4 to wind, 9 to loads of stones falling, 31 to the fall of a heavy body, and by 29 per cent. toexplosions; that is, 31 per cent. of the observers refer to types of long, and 69 to types of short, duration. The beginning of the sound preceded that of the shock in 49 per cent. of the records, coincided with it in 24, and followed it in 27, per cent. ; while the end of the sound preceded that of the shock in 13 per cent. of the records, coincided with it in 16, and followed it in 71, per cent. The duration of the sound was greater than that of the shock in 87, and equal to it in 13, per cent. of the records. In the rapid decline of intensity outwards from the epicentre, and in the nature of the sound-phenomena, the Pendleton earth-shake differs widely from other shocks in Great Britain. (i) Decline of Intensity.—During the last seventeen years there have been eight British earthquakes of intensity 7 (and nearly 8), namely, the Inverness earthquakes of 1890 and 1901, the Pembroke earthquakes of 1892 and 1893, the Derby earthquakes of 1903 and 1904, the Carnarvon earthquake of 1903, and the Doncaster earth- quake of 1905. In the following Table, the average areas contained by the different isoseismals are contrasted with the corresponding figures for the Pendleton earth-shake :— 174 Dr. OC. Davison—The Pendleton Earth-shake. | AREA IN SQUARE MitEs. IsosEISMAL. Average of the Pendleton above earthquakes. earth-shake. di 500 4 6 2,500 21 5 8,300 56 4 22,000 144 (ii) Sound-Phenomena.—In earthquakes which disturb an area of not more than a few hundred square miles the average percentage of audibility is about 98, and the sound-area coincides with, or over- laps, the disturbed area. Thus, in its audibility and contracted sound-area, the Pendleton earth-shake differs from other shocks with a small disturbed area. Nor does it differ less in the nature of the sound, as will be seen from the next Table, in which the figures represent percentages of the total number of comparisons to the different types mentioned, for slight British earthquakes, the Pendleton earth-shake, and similar earth-shakes of small and approximately circular disturbed areas. OUND SLY PE SLIGHT PENDLETON SMALL | Tal , EartuqQuakess. | EARTH-SHAKE. | EARTH-SHAKES. Passing waggons, etc. 31 14 =e Thunder Ee ioe OD 13 6 Wind , 3 4 Jee Loads of stones falling 8 9 12 Fall of heavy Roe 6 31 35 Explosions ... : 14 29 47 Miscellaneous «8 4 SAC cat The Pendleton earth-shake bears, indeed, a closer resemblance to the earthquakes which are characteristic of volcanic regions. For the sake of comparison, I reproduce in Fig. 2 the map of the isoseismal lines of the Etnean earthquake of August 8, 1894, on half the scale of the map of the Pendleton shake. The curve marked A bounds the ruinous zone, in which buildings were destroyed and several persons killed. The curve B bounds the “very strong” zone, in which slight damage to buildings occurred ; the curve C the “strong” zone, in which the shock was strong enough to make lamps, etc., swing; while, in the “slight” zone indicated by the curve D, the shock was just strong enough to be sensible. In both cases it is clear, from the rapid decline in intensity, that the focus was situated at a very small depth. Secondly, in the Pendleton earth-shake, it follows, from the nature of the sound, that the focus was of larger dimensions than in the weak earth-shakes, 1M. Baratta, ‘‘Intorno ai recenti fenomeni endogeni avvenuti nella regione Etnea’?: Boll. della Soc. Geogr. Ital., Oct. 1894. ee Dr. C. Davison—The Pendieton Earth-shake. 175 but smaller than in that of the slight, but true, earthquakes. Judging from the lengths of the axes of the inner isoseismal, it can hardly have been less than one mile, and may have been as much as one and a half miles, in length. If the earth-shake were due to fault-slipping, the direction of the originating fault must be parallel or nearly so to that of the longer axes of the isoseismal lines, or about N. 387° W. to 8. 37° H.; its hade being indeterminate, since each pair of isoseismal lines is separated by the same distance on both sides of the longer axes.’ iS Etna (crater) ©\ Riposto |} Latferana fe} Wicolosi Seater Fig. 2. Scale of Diles Fic. 2,—Isoseismal lines of Etnean Earthquake, Aug. 8th, 1894. Now, in the neighbourhood of Pendleton, the mean direction of the Pendleton fault is from N. 84° W. to 8. 34° E., and from its position, as indicated by the broken line on the map, we may, 1 This would be the case if the vertical dimension of the focus was small. 176 A. Harker—A Cordierite-bearing Lava I think, conclude that the earth-shake was due probably to a slip of this fault, but possibly to a subsidence along a band determined by, and closely adjoining, the fault. What the depth of the focus was we have no means of determining exactly, but it can hardly have been greater, and was probably much less, than a quarter of a mile, that is, considerably less than the depth of the present workings, which are from 800 to 1,100 yards below the surface. That the shock was primarily due to work in connection with the mines there can, I think, be little doubt. The slip, whether along the fault or otherwise, can hardly have been precipitated directly by the withdrawal of the coal, but rather, as suggested to me by Mr. Joseph Dickinson, by the pumping of water in the overlying beds.*| On this supposition, the slight depth of the focus, its great horizontal and small vertical dimensions, and the long interval that has elapsed since the working of the coal near the fault, would all receive a satisfactory explanation. VI.—A CorpIERITE-BEARING LAvA FROM THE LAKE DistRiI0T. By Atrrep Harker, M.A., F.R.S. LTHOUGH the volcanic rocks of the English Lake District have received notice from time to time, any systematic account of them from the petrographical side has yet to be written. The most recent contribution, by the late Mr. E. E. Walker,’ treated especially of the mode of occurrence of the garnet, which is so common a constituent, not only of the lavas and tuffs, but of the associated intrusive rocks, probably referable to the same Ordovician age. There can be no doubt that this mineral is sometimes a primary constituent, but very often a product of metamorphism. The object of the present note is to record the occurrence in one instance of a rarer mineral, which has not hitherto been observed in this series of rocks. Cordierite is found as a product of thermal meta- morphism in the Coniston Flags near the Shap Granite,’ and in the Skiddaw Slates of the Skiddaw granite area.? In the latter it is remarkably abundant and wide-spread.® The mineral is now found to occur, as an exceptional constituent, in the volcanic series. The specimen was collected sixteen years ago on Sty Head Pass, just south of the watershed. As it does not, to the eye, present any unusual appearance, its occurrence was not more particularly noted. It comes then in the midst of the volcanic succession, between the principal group of basic lavas and the thick breccias and tuffs which build the central mountains of the district. Dr. Marr* has expressed the opinion that a large part of the garnetiferous rocks which occur 1 For a similar suggestion see Grou. Maa., Dec. V, Vol. II (1905), p. 223. 2 Quart. Journ. Geol. Soc., vol. lx (1904), pp. 70-104. 3 Hutchings, Grou. Maa., 1894, pp. 65, 66. * Harker, ibid., pp. 169, 170. 5 Harker, Naturalist, 1906. 6 Proc, Geol. Assoc., vol. xvi (1900), pp. 476, 477, and map, pl. xiii. from the Lake District. 177 at or about this horizon are intrusive; but the rock in question has the characters of a lava, and those with which it is associated are apparently lavas and breccias. Most of these rocks on Sty Head Pass are more or less richly garnetiferous, but this specimen contains no garnet. A thin slice (No. 1240 of the Sedgwick Museum collection) shows crystals of cordierite and felspar, with other minerals less abundant, in a fine-textured felspathic ground-mass. The cordierite crystals are about ‘03 inch long and -02 inch broad, and are invariably complex twins. A cross-section shows a hexagonal outline and, between crossed nicols, the well-known division into six fields, of which each opposite pair have like optical orientation. The mineral is partly fresh, partly converted into a finely divided scaly aggregate of a pale yellowish green colour, which may be identified with the usual ‘ pinite’ alteration-product, probably a mixture of white mica and chlorite. The porphyritic felspars, giving rectangular sections 02 to -05 inch long, usually show twin-lamelle, with the low extinction-angles of oligoclase. There are also untwinned crystals, which seem to be orthoclase. A few chloritic and ferruginous patches probably represent decayed augite, and there are occasional small crystals of magnetite and apatite. The ground-mass consists essentially of minute felspar rods with sensibly straight extinction. It thus appears that the rock has trachytic rather than andesitic characters, but it is not fresh enough for a very satisfactory diagnosis. It is well known that cordierite occurs in some abundance in certain volcanic rocks, notably in andesites in the Hifel and the Cabo de Gata district. In such cases, even when the mode of occurrence of the mineral proves it to have crystallized from the igneous magma, there is evidence that the magma had been contaminated by dissolving non-igneous material.! A like origin may perhaps be suspected in the case of the cordierite (usually replaced by ‘ pinite’) in some granites and quartz-porphyries, as in Cornwall, Brittany, and the Black Forest. Nevertheless, there is no obvious reason why cordierite should not occur exceptionally (as corundum undoubtedly does) as a normal constituent of igneous rocks. In the Sty Head lava there is nothing to suggest directly that the magma has enclosed and absorbed foreign material, and the rock occurs in the midst of a thick series of purely volcanic nature. Excepting the Skiddaw Slates at the base, which contain a few unimportant lava-flows, and the Coniston Limestone group at the top, with which the latest lavas are interbedded, the Lake District succession presents an unbroken sequence of volcanic rocks. with no trace of sedimentary material. Without expressing any opinion as to the origin of the cordierite, I leave the question in the hope that it may be elucidated by the discovery of other oecurrences. 1 For a discussion of this question see Teall, Proc. Geol. Assoc., vol. xvi (1899), pp. 61-74. DECADE V.—VOL. III.—NO. IV. 12 178 Reports and Proceedings—Geological Society of London. Re SO ees) LANG 2s, © Charest etsy Se —o— GEOLOGIOAL Society or Lonpon. I.—February 16th, 1906.—J. E. Marr, Sc.D., F.R.S., President, in the Chair. Annuat GENERAL MEETING. The Reports of the Council and of the Library and Museum Committee for the year 1905, proofs of which had been previously distributed to the Fellows, were read. This year again the Council announced a decrease in the number of Fellows, although the number elected was 48 (2 more than in 1904). Of these, 36 paid their admission fees before the end of the year; making, with 13 previously elected Fellows, a total accession of 49 in the course of the twelve months under review. During the same period, the losses by death, resignation, and removal amounted to 61 (8 more than in 1904), the actual decrease in the number of Fellows being, therefore, 12 (as compared with a decrease of 3 in 1904). The total number of Fellows on December 31st, 1905, was 1289. The balance-sheet for that year showed receipts to the amount. of £3,871 9s. Td. (including a balance of £409 7s. Td. brought forward from 1904), and an expenditure of £5,066 6s. 10d. It was stated that increasingly rapid progress was being made with Mr. C. Davies Sherborn’s manuscript Card-Catalogue of the Library, and that “the end was now in sight.” It was further stated that, Mr. Sherborn having intimated his inability to undertake, after the end of 1905, the preparation of the catalogue-slips for the International Catalogue of Scientific Literature, a Committee was appointed to review the part hitherto taken by the Society in furnishing the slips for British Geology to the Central Bureau, and that Committee had recommended the discontinuance of the work under present conditions. The Com- mittee had also recommended that modifications be made in the Society’s Record of Geological Literature, so as to include all geological literature published in Britain, and that slips from the aforesaid Record shall be available for the purposes of the Central Bureau of the International Catalogue of Scientific Literature. It was announced that substantial progress had been made in the preparation of the forthcoming Centenary Record of the Society, initiated by Mr. Horace B. Woodward. Reference was made to the lamented decease of Dr. W. T. Blanford, and to the steps taken to fill up the vacancies in the Treasurership and on the Council which his decease had created. The list of Awards of the various Medals and Proceeds of Donation Funds in the gift of the Council was read. The Report of the Library and Museum Committee enumerated the extensive additions made to the Society’s Library, and gave some details as to the Card-Catalogue. Ee Reports and Proceedings—Geological Society of London. 179 _ The Reports having been received, the President presented the Wollaston Medal to Dr. Henry Woodward, F.R.S., addressing him as follows :— Dr. Woodward,—The Wollaston Medal, the highest honour which it is in the power of the Society to bestow, has been unanimously awarded to you by the Council in recognition of your researches concerning the mineral structure of the Earth, and particularly of your valuable contributions to the science of Paleon- tology, and more especially to our knowledge of the fossil Arthropoda. There are many reasons why your fellow-workers and friends should rejoice at this award. r As Director of the Geological Department of the British Museum, your duties must have been heavy, but you have found time for an extraordinary amount of work in addition to that necessitated by your official position. Many are the learned Societies which are indebted to you for counsel. Besides our own I may mention the Zoological, Paleontographical, Microscopical, and Malacological Societies, the Geologists’ Association, and the Museums Association. Your labours on behalf of these Societies have been recognized by your, haying been called upon to occupy the Presidential Chair of the greater number of them. The debt which geologists owe to you as Editor of the GrotogrcaAL MAGAZINE was admitted by Dr. Bonney, when, twenty years ago, on behalf of numerous subscribers he presented a testimonial to you in these apartments. That debt is now more than doubled, for you have been Editor of the Magazine for over forty years, and during the greater part of that period its chief Editor. In addition to this we are deeply grateful to you, and especially to her who has ever interested herself in your labours, for the ‘‘Index to the Geological Magazine’? which appeared last year. Itis a happy circumstance that the bestowal of this Medal upon you occurs in a month which witnesses the publication of the 500th number of that Magazine. Long may the Magazine continue to flourish in the hands of its present Editor ! Dr. Bonney, on the occasion to which I have alluded, paid a just tribute to your great kindness to other workers, and especially to the encouragement that you have ever given to the young. I gratefully remember the time when I, as an under- graduate, entered with feelings of trepidation the room of the Geological Department of the British Museum, then at Bloomsbury, how I was at once put at ease by you, and the help which I received. My experience has been that of many, and all who haye benefited by your kindness will feel pleasure in the award of this Medal to you. But although the services which I have mentioned are reasons for rejoicing at the award, they are merely subsidiary reasons for the bestowal of the Medal. The recipients of the Wollaston Medal have always qualified for it by increasing our knowledge of the mineral structure of the Earth by their own researches. It is unnecessary to say that you also have done this. Your contributions to the study ot the paleontology of the Invertebrates, and especially of the fossil Arthropoda, are known to all workers, and need no further comment on my part. I am glad that during the years of my occupation of this Chair the Wollaston Medal has been awarded to two British geologists, the one a distinguished petrologist, the other an eminent paleontologist. Dr. Woodward, in reply, said :— Mr. President, —It is now forty years ago (on February 16th, 1866) that I received from the President, Mr. William John Hamilton, at Somerset House, the award of the Balance of the Wollaston Donation Fund. I was then only a youth of 34 years of age, and little dreamed that I should be honoured by receiving at your hands to-day this Medal, the highest recognition that the Council can bestow. I feel justified, however, in attributing this great honour quite as much to the personal friendship of the Council as to any merit of my own; but I am happy to find that this friendly disposition is also shared by a large body of the Fellows of the Society outside the Council, who have by letter and word of mouth expressed their kindly approval of the Council’s choice. I was elected 'a Fellow of this Society in 1864, and from 1867 until 1902 I have been (off and on) a Member of the Council (for a period of 35 years), and served also the office of President (1894-6), so that I naturally feel more deeply interested in the welfare of this Society than in any other, although I have been for many years, and am still, intimately associated with several other scientific bodies of kindred pursuits to our own. 180 Reports and Proceedings—Geological Society of London. You have alluded, Sir, in very favourable terms to my work, and I specially desire to thank you for your most kind reference to Mrs. Woodward’s assistance in it, during all the years which are past, when we have worked side by side ; but it would be incredible if, having had the grand opportunities afforded to me during forty-three years in the British Museum, I had not winnowed out some store of good grain as a contribution to the stock of paleontological knowledge in so long a lite. Whether as Editor of the Grotocrcan Macazine or in the Geological Depart- ment of the British Museum, my greatest aim and object in life has always been to be of assistance to others, and for this, I am glad to say, I have won the friendship and good-will of a very large circle of my fellow-workers, who have by their kindness rewarded me a hundredfold, as you, Sir, in the name of the Council have done to-day by the bestowal of this Medal, for which my grateful thanks are due. The President then presented the Murchison Medal to Mr. Charles Thomas Clough, M.A., of H.M. Geological Survey, addressing him in the following words :— Mr. Clough, —The Council have awarded the Murchison Medal to you, in recognition of your invaluable contributions to Geological Science by means of the maps and memoirs executed by you for H.M. Geological Survey. Your detailed observations on the igneous and metamorphic rocks of Northern Britain have furnished geologists with most important material for the elucidation of many intricate problems. Your work is largely recorded in the various Memoirs of the Geological Survey. I may especially refer to those Memoirs which treat of the geology of the Cheviot Hills and of the Cowal District of Argyllshire, although your contributions to our science are also included in several other volumes of which, you are one of the authors. Your work is also recorded on the maps of those areas which you have surveyed. To produce those maps required, in addition to the ordinary accomplishments of a geological surveyor, petrographical and other knowledge of a very special kind, and they form a fitting monument to your skill. Their remarkable execution was recognized by the selection of certain of those of Ross-shire for exhibition at the St. Louis Exhibition, as examples of the maps on the 6 inch scale which are produced by the Geological Surveyors of this country. Once again the Murchison Medal is awarded to a member of that Survey of which the founder was for so long chief. It is a source of gratification to me that, in the two years of my office as President, medals have been awarded to two old members of my own College, pupils of my College tutor, Dr. Bonney. Mr. Clough replied as follows :— Mr. President,—I thank the Council of the Geological Society very much for the honour that they have conferred upon me, and you, Sir, for the very kind words in which you have spoken of my work. JI am conscious that this presentation is a matter not purely to myself—that it is another recognition by this Society of the value of the detailed co-operative work carried on by the Geological Survey—and it is to me a great additional pleasure to be thus tacitly associated in your minds with colleagues and friends with whom I have spent so many happy years. I have now been on the staff of the Geological Survey for more than thirty years, and I have seen that we sometimes get on the wrong track—that we have our ‘downs. as well as our ‘ups ’—but we feel that, through all vicissitudes, a foundation of honest work is always appreciated by our brethren of the hammer. It is a pleasure also on this occasion to acknowledge my personal indebtedness to my old friends and teachers of Cambridge days, and particularly to Professor Bonney and Professor Hughes. I feel indeed that I owe to others more than I can tell. || In handing the Lyell Medal, awarded to Professor Frank Dawson Adams, Ph.D., to Sir Archibald Geikie, Sc.D., Sec.R.S., for trans- mission to the recipient, the President addressed him as follows :— Sir Archibald Geikie,—The Lyell Medal is awarded to Professor Frank D. Adams as a mark of honorary distinction, and as an expression on the part of the Council that he has deserved well of the science, particularly by his contributions to our knowledge of the Geology of Canada. Reports and Proceedings—Geological Society of London. 181- Professor Adams has been actively engaged in the study of the rocks of the great Dominion, and by work in the field and the laboratory has contributed largely to our knowledge of their petrography and their genesis. The study of those ancient rocks, the pre-Cambrian age of which was first demonstrated in Canada, has advanced far during recent years; but they are still to some degree enshrouded in mystery, and the labours of our Medallist are throwing light upon the obscurity. He is also occupied with work among igneous rocks bearing upon problems connected with petrographical provinces and the differentiation of igneous magmas. I may more especially allude to his paper on ‘‘ The Monteregian Hills—a Canadian Petrographical Province,’’ published in the Journal of Geology for April—May, 1903. Nor has he occupied himself with observation to the neglect of experiment, and one result of his laboratory work is that most interesting and suggestive paper, ‘* An Experimental Investigation into the Flow of Marble,” written in conjunction with Dr. J. T. Nicholson, and published in the Philosophical Transactions of the Royal Society (ser. A, vol. excy, p. 363). The experiments described in this paper tend to prove that not only ‘¢ The solid earth on which we stand, In tracts of fluent heat began, And grew to seeming random forms, The seeming prey of cyclic storms,” but that, even now, internal tracts which are in the ordinary sense solid, “ flow From form to form,” with results which have a most important effect upon various rock-structures. Professor Adams is successful also as a teacher, and we rejoice to know that, under his care, a geological school flourishes in McGill University, endeared to us all by its association with the name of Sir William Dawson. We regret Professor Adams’s absence to-day. ‘Let us hope that we may welcome him and many other geologists who are advancing our science in many parts of the Empire, on that auspicious occasion in the coming year when we shall celebrate the centenary of the foundation of our Society. Sir Archibald Geikie, in reply, expressed the pleasure with which he received this Medal on behalf of his friend Professor Adams, from whom the following letter had just been received in answer to the Secretary’s announcement of the award :— ‘* Petrographical Laboratory, McGill University, Montreal, February 2nd, 1906. “* Professor Edmund J. Garwood, M.A., Secretary of the Geological Society. ‘* Dear Sir,— ‘JT have received your kind letter conveying the very welcome and most unexpected information that the Council of the Geological Society have this year awarded to me the Lyell Medal. I regret extremely that it is impossible for me to be in London at the time of the annual meeting, so that I might have the pleasure of receiving the Medal in person. *