omen Prigethc in Me net. Keira ne alee io cite hain bet pinta adie nmanig Me «tie met wlhee ‘ 4 Es Sw aS OES —_ Aj \ THE GEOLOGICAL MAGAZINE: Monthly Journal of Geology: WITH WHICH I8 INCORPORATED hh GE OLOGIS &.7 NOS. CCCXXXI. TO CCCXLII, EDITED BY HENRY WOODWARD, LL.D., F.B.S,, F.G.S., F.Z.8., F.B.M.S., OF THE BRITISH MUSEUM OF NATURAL HISTORY 5 VICE-PRESIDENT OF THE PALMONTOGRAPHICAL SOCIETY, MEMBER OF THE LYCEUM OF NATUBAL HISTORY, NEW YORK; AND OF THE AMERICAN PHILOSOPHICAL SOCIETY, PHILADELPHIA; HONORARY MEMBER GF THE YORKSHIRE PHILOSOPHICAL SGCIETY; OF THE GEOLOGISTS’ ASSOCIATION, LONDON: OF THE GEOLOGICAL SOCIETIES OF EDINBURGH, GLASGOW, HALIFAXE, LEVEEPOOL, AND NOR= WICK; CORRESPONDING MEMBER OF THE GEOLOGICAL SOCEETY OF BELGIUM; OF THE IMPERIAL SOCIETY OF NATURAL HISTORY OF MOSCOW; OFTHE NATURAL HISTORY SOCIETY OF MONTREAL; AND OF THE MALACOLOGICAL SOCIETY OF BELGIUM, ASSISTED BY ROBERT ETHERIDGE, F.BS. L. & E, F.GS., F.CS., &., WILFRID H. HUDLESTON, M.A., F.R.S., Prus.G.8., F.L.S., F.C.S. AND GEORGE J. HINDE, Pu.D., V.P.G.S., &c. NEW SERIES. DECADE III. VOL. IX. JANUARY—DECEMBER, 1892. LONDON: KEGAN PAUL, TRENCH, TRUBNER & Co., Lumen, PATERNOSTER HOUSE, CHARING CROSS ROAD ARAN LS Tiss F. SAVY, 77, BOULEVART ST.-GERMAIN, A ARTS. OF 1892. ‘ 15, HE! SHEISLe ee eee PRINTED BY STEPHEN AUSTIN AND SONS. . y 2ijue ‘Pad i; ty - Le 5 vis 4 1 ‘ ‘ - r z J | iPad iF a J | s ) ~ e* i x 173 - ‘ ; ‘ 7 re 3 r se fey, } ‘fl ant le y at. A rit ers ues Ny ~ 7 RAGA at *t x KOM es 2 eee Par 5 LS a ‘ ? 4 ‘ a, ot Adis i ‘. lewis A é ; ’ nl a Mth! —__ 1.—On toe Lower Devontan Fisu-Fauna of CampBELLton, New BRUNSWICK. By Arraur Smirx Woopwarp, F.L.S., F.G.S. (PLATE I.) HE Lower Devonian Fish-Fauna of Campbellton, New Brunswick, has already been described by Mr. Whiteaves,' of the Canadian Geological Survey, and Dr. Traquair,? of Edinburgh; and a few supplementary observations are published in the British Museum Catalogue of Fossil Fishes, Part II. (1891). Much, however, still remains to be learned concerning the skeletal anatomy of the genera and species already determined; and many types of early fishes will doubtless soon be discovered by future explorers of the formation and locality in question. A new series of specimens just received by the British Museum from Mr. R. F. Damon, of Weymouth, adds some small items of interest to our knowledge of the subject; and the following notes relate to the advance thus made. The fossils under discussion were collected last summer by Mr. Jex, and are all much crushed and flattened in the usual manner. ELASMOBRANCHIT. Genus, ProToDUs, nov. A genus known only by detached teeth. Dental crown consisting of a single robust, solid, conical cusp, invested with gano-dentine ; root large, undivided, laterally expanded, and antero-posteriorly compressed. That the tooth thus defined is not the laniary of a Crossopterygian attached to its basal bone is proved by the examination of a micro- scopical section, which leaves little doubt as to its Hlasmobranch relationships. Protodus is thus the earliest tooth referable to the Elasmobranchii hitherto determined, and is especially remarkable on account of the form of the root. There is much reason to believe that all the more primitive Hlasmobranch teeth possess a horizontally expanded base (or root), while antero-posterior compression is the 1 J. F. Whiteaves, Canadian Naturalist, n.s. vol. x. (1881), pp. 93-100: also “ GEOLOGICAL Soctrty or Lonpon. I.—Nov. 11, 1891.—Sir Archibald Geikie, D.Sc., LL.D., F.R.S., President, in the Chair.—The following communications were read : 1. “On Daerytherium ovinum from the Isle of Wight and Quercy.” By R. Lydekker, Esq., B.A., F.G.S. The author described a cranium and mandible of Dacrytherium Cayluxi from the Quercy Phosphorites, which proved the identity of this form with the Dichobune ovina of Owen from the Oligocene of the Isle of Wight. The species should thus be known as Dacry- therium ovinum. It was shown that the mandible referred by Filhol to D. Cayluai belongs to another animal. 2. “Supplementary Remarks on Glen Roy.” By T. F. Jamieson, Esq., F.G.S. The author discusses the conditions that preceded the formation of the Glen Roy Lake, and appeals to a rain-map of Scotland in support of his contention that the main snowfall in Glacial times would be on the western mountains. He gives reasons for supposing that, previously to the formation of the lake, the valleys of the Lochaber lakes were occupied by ice, and that the period of the formation of the lakes was that of the decay of the last Ice-sheet. He supports the correctness of the mapping of the terraces by the officers of the Ordnance Survey, and shows how the absence of the two upper terraces in Glen Spean and of the highest terrace in Glen Glaster simplifies the explanation of the formation of the lakes by ice-barriers. The alluvium of Bohuntine is considered to be the gravel and mud that fell into the lake from the front of the ice when it stood at the mouth of Glen Roy during the formation of the two upper lines. During the last stage of the lake, the ice in the valley of the Cale- donian canal is believed to have constituted the main barrier, whilst the Corry N’Hoin glacier played only a subordinate part. The author suggests the possibility of a débdcle during the drop of water from the level of the highest to that of the middle terrace ; and in support of this calls attention to the breaking down of the moraines of the Treig glacier at the mouth of the Rough Burn. He believes that when the water dropped to the level of the lowest 40 Reports and Proceedings— terrace, it drained away quietly, at any rate until it receded from Upper Glen Roy. In discussing Nicol’s objections, he maintains that notches would not be cut at the level of the cols, and observes that the discrepancy between the heights of the terraces and those of the cols has probably been increased by the growth of peat over most of the ground about the watersheds. The horizontality of the terraces is stated to be a fact, and cases are given where waterworn pebbles are found in connexion with the “roads,” these being especially noticeable in places where the south- west winds would fully exert their influence, and the structure of the terraces is considered to be such as would be produced at the margins of ice-dammed lakes. Further information is supplied con- cerning the distribution of the boulders of Glen Spean syenite. These are found on the north side of the Spean Valley at the height of 2000 feet above the sea and 1400 feet above the river, and fragments of the syenite have been carried towards the north-east, north, and north-west. In an Appendix, the author discusses Prof. Prestwich’s remarks on the deltas, and his theory of the formation of the terraces. II.—Nov. 25, 1891.—Sir Archibald Geikie, D.Sc., LL.D., F.R.S., President, in the Chair.—The following communications were read : 1. “On the Os pubis of Polacanthus Fowi.” By Professor H. G. Seeley, F.R.S., F.G.S. Hitherto the evidence of the systematic position of Polacanthus has not been very precise. The author has detected the missing pubis as an isolated specimen. This he regards as the anterior portion of the left pubis, and appends a full description of the bone. He furthermore gives a critical account of our knowledge of other pelvic bones of the genus, and is led to associate Agathaumus, Cra- teomus, Omosaurus, and Palacanthus in near alliance, in the Scelido- saurian division of the Order Ornithischia. 2. «A Comparison of the Red Rocks of the South Devon Coast with those of the Midland and Western Counties.” By Professor Edward Hull, LL.D., F.R.S., F.G.S. The author believes, with Dr. Irving, that the Red Rocks of Devonshire are representatives of the Permian and Trias, which occupy so large a portion of the district bordering Wales and Salop, and which extend into the Midland Counties, and comments on the remarkable resemblance between the representative beds on either side of the dividing ridge of Paleozoic rocks which underlies East Anglia and emerges beneath the Jurassic strata in Somersetshire. He believes that the breccia forming the base of the series in the Torquay district is a representative of the Lower Permian division, but differs from Dr. Irving, in assigning the red sandstones and marls of Exmouth to the Trias, and not to the Permian, as that author has done. He compares them with the Lower Red and Mottled Sandstones, and regards the Marls as of local origin, thus causing the beds to diverge from the normal type. Geological Society of London. 41 The Budleigh Salterton Pebble-beds, with overlying sandstones and pebbly beds, he assigns to the horizon of the Pebble-beds of the Midland area, and points out that fossils of Silurian and Devonian types occur in the pebbles of both areas. The Upper Division of the Bunter is well shown at Sidmouth, and the author takes a calcareous breccia, two feet thick, which is found in the cliffs, as the basement bed of the Keuper division. _ 8. “Supplementary Note to the Paper on the ‘Red Rocks of the Devon Coast-section, Q.J.G.S. 1888.” By the Rev. A. Irving, D.Se., B.A., F.G.S. In this note the author accepts Prof. Hull’s determination (see above) of the breccia at Sidmouth as the base of the Keuper, and discusses the age of the sandstones containing vertebrate remains discovered by Messrs. Whitaker, Metcalfe, and Johnston-Lavis. He brings forward evidence in support of his view that these are really of Upper Bunter age, notwithstanding the character of the organisms. He adds new material in support of his contention that the sand- stones and marls which Prof. Hull assigns to the Lower Bunter are really Permian; but he is inclined to think that the breccias (in part, at least) pass laterally into the sandstones, and do not underlie them. From this it follows that the break between the Permian and Trias of Devon is marked by the absence of the Lower Bunter of the Midlands, and the author quotes remarks of Mr. Ussher in sup- port of his view that there is an unconformity at the base of the Pebble- bed. In conclusion the author refers to the difficulties of ascertaining the exact age of the breccias, and notes that we cannot prove that the highest Carboniferous beds are present in Devonshire. He observes that there is no valid reason why the great breccia-sand- stone series of Devon should not be the true equivalent of the Lower Rothliegendes both in time and position in the sequence, and that some portions of them may be even older than the Rothliegendes of some districts. He discusses the evidence furnished by the igneous rocks, and points out the abnormal position both for the British and German areas which these would occupy, if the breccias were of Triassic age. I1].—December 9, 1891.—Sir Archibald Geikie, D.Sc., LL.D., F.R.S., President, in the Chair.—The following communications were read :— 1. “On the Rocks mapped as Cambrian in Caernarvonshire.” By the Rev. J. F. Blake, M.A., F.G.S. In this paper the following is given as a definite succession in the Cambrian series:—1. Pale Slates; 2. Upper Purple Slates; 3. St. Ann’s Grit; 4. Lower Purple Slates; 5. Rhiw-wn Grit; 6. Hard banded Pale Slates and Hilleflintas; 7. Bangor Conglomerate ; 8. Hard banded Pale Slates and Hilleflintas; 9. Bangor Breccia ; 10. Blue blanded laminated Grits; 11. Tairffynnon Conglomerate ; 12. Blue banded laminated Grits; 13. Brithdir quartz-felsite Grit. 42 Reports and Proceedings—Geological Society of London. The general succession is argued to be the same in the isolated portion east and south of Bangor as in the main mass. The existence or otherwise of a base on the mainland is considered to depend on the age assigned to the Dinorwic felsite, and the presence of the summit-beds to depend on whether the Bronllwyd Grit (stated to belong to the overlying group) rests conformably or unconformably on the Cambrian rocks. It is argued that the rocks to the west of the Llyn Padarn felsite belong to the lower part of the series and those to the east to the upper, and that the felsite is a volcanic complex belonging to the middle of the Cambrian period. A post-Cambrian age is assigned to the conglomerates of Moel Tryfan and Llyn Padarn, thus causing the break at the base of the Silurian system to assume an increased importance. 2. “The Subterranean Denudation of the Glacial Drift, a probable Cause of submerged Peat and Forest-beds.” By W. Shone, Esq., F.G.S. A description is given of a section at Upton, Cheshire, where Boulder-clay rests upon the ‘“ mid-glacial sands.” The Boulder- clay sinks to a lower level in the small valleys which are cut through into the sands; and the author supposes that this is due to the subterranean denudation of the sands, which would be greatest near the valleys, and become less at a distance from them. He considers such denudation is capable of producing submerged peat and forest- beds, and accounts for the splitting of peat-beds, as described by Mr. G. H. Morton, by a somewhat similar action, which he believes may have also operated in Carboniferous times, causing the splitting of coal-seams. 3. ‘High-Level Glacial Gravels, Gloppa, Cyrn-y-bwch, near Oswestry.” By A. C. Nicholson, Esq. Communicated by W. Shone, Esq., F.G.S. These gravels are found at Gloppa, and are situated at a height of from 900 to 1160 feet above sea-level, on the eastern slope of a ridge of Millstone Grit which forms the western border of the Cheshire and Shropshire plain. The beds present the appearance of having been abruptly cut off on the north-eastern slope. The gravels are in places much contorted, and false-bedding is frequent. They contain numerous striated erratics. Amongst the boulders are Silurian grits and argillites, granites like those of Eskdale, Criffel, etc., Carboniferous rocks, Lias shale, and Chalk flints. The shells are often broken, rolled, and striated, but the bulk of them are in fairly good condition. A list of the shells is given, including nine Arctic and Scandina- vian forms not now living in British seas, nine northern types, also found in British seas, two southern types, and nearly fifty species of ordinary British forms. Comparative lists of the shells of Moel Tryfan and of those now living in Liverpool Bay are placed side by side with the list of shells from Gloppa. Correspondence—Prof. Bonney—Prof. Cole. 43 CORRESPONDENCE. GRANITE CUTTING CRETACEOUS ROCKS—A CORRECTION. Srr,—In my Presidential Address to the Geological Society in 1885 (Proc. Geol. Soc. vol. xli. p. 75), I speak of having seen in the Alps “perfectly typical granite cutting Lower Cretaceous strata.” The remark was founded on a note made in 1874. Iam sorry to say that in these words there are two mistakes: the rock is of Tertiary not of Secondary age: the granite is not intrusive. As to the former matter I was misled by a small map, the only one which I then possessed ; as to the latter I fell into a trap. The rock looked like a dyke of grey, not very coarse, granite cutting through a dark schistose rock. I was puzzled at not finding more distinct evidence of contact metamorphism ; but this solitary slab-like mass in its general form so closely resembled a dyke, that I did not at that time suspect its true nature. Shortly after the above statement was published, a correspondent (I think Prof. Vélain) intimated to me that he believed I had made a mistake; my own doubts kept increasing ; and last summer I again visited the spot, which is on the road from Sepey to Ormond Dessus. The apparent dyke is one of those large erratics which occur not unfrequently in the Flysch of Switzerland, and others may be found at no great distance. How it was that I missed them on the former occasion, and thus failed to have suspicions awakened, I cannot understand, unless it be that changes have been made in the road. Possibly, as I had then worked but little at rocks, something else may have diverted my attention. Be that as it may, there can be no doubt that I made a mistake, and hope that there are not many such on my geological conscience. T. G. Bonney. NOTE ON MR. HUTCHINGS’S PAPER ON SOME LAKE-DISTRICT ROCKS. Sir,—As far as the evidence of the rock-sections goes, the rock from Thornthwaite Crag, described by Mr. W. M. Hutchings, may well be an altered trachyte (Grot. Mac. 1891, p. 543). But the analysis given would indicate a rock nearer andesite, like so many of the “oligoclase-trachytes”’ of the Auvergne. Considering how trachytes and andesites are associated in the field, and how the same lava-flow may contain varying proportions of porphyritic crystals in various parts, and may consequently yield alkalies in different proportions on analysis of different specimens, I think we must receive with caution the suggestion of an occult rather than a purely chemical cause for the differences between the crystallized - constituents of the two types of rock. The analysis referred to by Mr. Hutchings as given in “ Aids in Practical Geology ” (p. 226 of that book) is that of a Sodalite-Trachyte of Ischia. Now I suspect that, had chlorine not been present, this rock would have developed albite and oligoclase in sufficient quantity to bring it at least to the verge of the andesite series. If we call the sodalite 44 Correspondence—Ur. Garwood—Mr. Springer. an “accessory” mineral, and deduct the soda required for its formation, we still have an excess of soda over potash in the rock; the monoclinic felspar present at Scarrupata, Ischia, is, no doubt, as is frequently the case, a soda-orthoclase. Such an analysis must not be regarded as typical of simple trachytes, but of the sodalite-trachytes, which, indeed, approach the phonolites. Judged by the bulk-analysis, then, the rock so clearly described by Mr. Hutchings has an affinity with the nepheline-trachytes (nepheline- phonolites) or the trachytic andesites. I fear any trace of original nepheline will have disappeared. Dusuin, 5th Dec. 1891. GRENVILLE A. J. CoLE. CONCRETIONS IN MAGNESIAN LIMESTONE. Sir,—If I am correct in thinking that Mr. Jukes-Browne con- siders that Carbonate of Lime was precipitated on the sea-floor during the formation of the Magnesian Limestone beds, 1 am inclined to agee with him; but this merely deals with the origin of beds of Magnesian Limestone, and does not account for the formation of the Concretions. If, however, he intended to suggest that the moisture contained in the deposit held the Carbonate of Lime in solution, I think the amount would be quite inadequate to account for the thick beds of concretions, and this method of origin would not explain the bedding planes which pass uninterruptedly through matrix and concretions alike. HK. J. GaRwoop. THE LATE P. HERBERT CARPENTER, M.A., D.Sc. (Cams.) F.R.S., F.L.S. The Editor has received the following note from Mr. FRanxK SPRINGER, joint-author with Mr. Wacbsmuth of numerous works and memoirs on the N. American Crinoidea. It is a high tribute of regret, regard and esteem from the United States for the loss of one whom we all deeply and sincerely mourn in Hngland.—Hpir. Grou. Maa. Dear Dr. Woopwarp,—It is with the most profound regret that I have learned the particulars of the death of our lamented friend Carpenter. It is difficult to aptly express the great loss it is to Wachsmuth and myself. Carpenter’s rare scientific attainments and broad learning are known wherever Zoologists exist, but to us, who have been in constant correspondence with him for fourteen years, I think his untimely death brings a keener sorrow than to any outside of the circle of his intimate friends and relations. We had the greatest reason and opportunity to admire and appreciate him. Notwithstanding our many animated controversies in print upon disputed questions of Echinoderm morphology, and still more numerous and earnest battles in private correspondence, in which many a promising theory was warmly advocated, combated, and given up on both sides, our acquaintance long ago assumed the phase of cordial friendship and high personal regard. This was still more firmly cemented by my visit to him, while in England in 1887-8, and we feel his loss now as a personal bereavement. We Oorrespondence—Mr. Lydekker—Dr. Callaway. 45 were in the most confidential communication relative to our various works on the Orinoids, especially the one now in progress. We always interchanged advance sheets of our publications, and some- times sent each other manuscript for examination and criticism. Carpenter was always the soul of honour in regard to information derived from these private communications, and was generous to the last degree in giving information from his great store of learning, whose value none could estimate higher than we. I should be very glad to know of any publications in England in recognition of his merits. Hoping this will find you very well, believe me always, very sincerely yours, Las Vrecas, New Mexico, FRANK SPRINGER. November 15th, 1891. “ANNALS OF BRITISH GEOLOGY’ FOR 1890. Sir,—It is not my intention to make any comments on the criticisms which the compiler of the volume bearing the above title has thought _ fit to introduce into the notices of my papers, as those who have even the most superficial acquaintance with the subject therein treated will be able to appreciate the value of such criticisms. When, however, I am deliberately charged with making a blunder, which exists only in the mind of the compiler, it is time to say something. In noticing the fourth part of my “Catalogue of Fossil Reptilia and Amphibia,” the compiler of the work in question goes eut of his way to state that I have changed the names Orthocorta to Orthopleurosaurus without giving any reason for so doing. Now (without commenting on the circumstance that he had the reason for this change staring him in the face), if the compiler had taken the trouble to look at the notes at the bottom of the page, he would have seen after the reference to the name Orthocorta, the word “« Hybrid.” R. Lypexker. UNCONFORMITIES BENEATH THE CAMBRIAN QUARTZITES IN SHROPSHIRE. Srr,—In the Groroctoat Magazine (1891), p. 485, is a paper by the Rey. J. F. Blake, in which he challenges some of my criticisms on his work in Shropshire. His chief assertions are the following: (1). That at Pontsford Hill the Longmynd Rocks in contact with the Rhyolite are altered. (2). That at Narnell’s Rock there is an unconformity separating Cambrian from “ Monian ” rocks. (3). That at Charlton Hill the conglomerates and grits are super- ficial, and are not a part of the Uriconian series. Paper-contests in geology are rather unsatisfactory work, and I therefore propose to attempt a settlement of these disputed points, and any others that may be agreed upon, in the following manner. A competent geologist, to be ‘selected by Mr. Blake and ‘myself, to visit the ground in our company, and to publish his conclusions. The disputant who is convinced of his error to publish his re- cantation, The disputant against whom the referee decides in the 46 Correspondence—Dr. Charles Ricketts. majority of cases to pay the travelling expenses of the referee. I am aware that disputes cannot always be settled in this way ; but the three sections I have named are so clear and simple, that a third party can hardly fail to come to an immediate decision, and we should select a person whose award would carry weight. If Mr. Blake refuses this challenge, I will offer to take any competent geologist to the sections, and to forfeit five gunieas to a hospital if I fail to convince him. (nu. CALLAWAY. November 20th, 1891. “ CONCRETIONS”’ IN MAGNESIAN LIMESTONES. Srr,—There is another possible method, besides those suggested by Messrs. Garwood and Jukes-Browne, by which the globular and pseudo-coralline and other forms so remarkable in the Magnesian Limestone of Durham may have originated—the mechanical; and this is slightly alluded to by Professor Sedgwick (page 92). Many years ago a friend presented me with a considerable series of specimens obtained from the neighbourhood of Sunderland; their examination seemed to indicate that their forms were due to mecha- nical action, but it was difficult to imagine how the principle on which a school-boy’s marbles, “alleys, tors and commoners,” are formed from cubical fragments of stone, could have been applied by natural means; nor did a visit to the extensive quarries at Fulwell, north of Sunderland, assist in solving the problem. The promontory on which Tynemouth Castle stands may possibly help to afford a solution. The strata forming the base of the cliff consist of Coal- measure Sandstone, on which rests a bed composed of angular frag- ments derived from the same, and over this the Permian Limestone has been deposited. This Limestone is full of cavities resembling in appearance some examples of vesicular trap. I would suggest that during the formation of the limestone, and whilst it was still in a more or less plastic state, gases evolved from the decomposition of vegetable matter forming beds of Coal made their way through the basement beds of limestone. Such vesicles as occur at Tynemouth might be expected to have been formed under these conditions, and it is quite possible that the globular forms of the so-called “concretions,” which occur near Sunderland, may have originated from a similar cause, though under somewhat different circumstances, such as the amount of gas evolved; the amount to which the lately deposited limestone had consolidated, ete. Whatever was the cause of the fashioning of the globular masses, the same must have been the instrument by which the coral-like forms were shaped. I much regret being so circumstanced that I could not conveni- ently carry out a series of experiments to determine the possibility of the globular forms being due to the cause suggested. The only rough attempt made was so far satisfactory that the passage of carbonic acid, generated beneath clay in a plastic state, resulted in the production of many small rounded forms. BirKENHEAD, November, 1891. CuarLes RicKsrTTs. Obituary—Ur. W. Kinsey Dover, F.GS. 47 NEEDLESS ALTERATION OF ZOOLOGICAL NAMES. Sir,—The want of a proper set of recognized canons to regulate the selection and retention of generic and specific names is becoming more and more urgent. We are constantly being told to abandon some well-known name because an older one has been found, or because it was previously given to some other organism ; but such reasons are not sufficient by themselves. ‘The author of a British Museum Catalogue has lately attempted to introduce the name of Meretriz instead of Cytherea, and that of Lampusia in place of Triton, two well-known genera of Mollusca; but the needlessness of the change has been exposed by writers in the pages of “ Nature,” and the author in question must be regarded as a culpable “disturber of the public peace” of mind. Such unnecessary interference with names engenders a feeling of opposition against any change of name, even when the change is desirable and well-founded. Cannot the Linnean and Zoological Societies take common action with the International Geological Congress in establishing an International Committee on nomenclature, to which all new names and all proposed alterations of names might be submitted? The following letter appeared in “Nature” for November, and might be reproduced in every Biological and Geological Magazine. Exeter, November 21. A. J. Jukes-Browne. Meretriz, Lamarck, 1799, versus Cytherea, Lamarck, 1806. In the notice of Mr. Newton’s ‘‘ List of Mollusca,”’ in ‘‘ Nature’’ of October 29 (vol. xliv. p. 610), I read as follows:—‘‘ Many old favourites have been thus relegated to obscurity, whilst fresh names, dug up from some forgotten corner, have, by the law of priority, taken their places. ‘Thus, Meretrix, Lamarck, 1799, takes the place of his better-known Cytherea of 1806, the latter having been applied by Fabricius in 1805 to a dipterous insect.’’ The Dipteron Cytherea obscura, Fab., 1805, was described nine years later than Mutio obscurus, Latreille (1796), which is the same species. Meigen, in his principal work (1820), acknowledged the priority, and the insect has been called Mutio ever since. As the typical species is the same for both genera, there is no chance whatever for Cytherea to be resuscitated, and it may well remain as the name of the Mollusk. I most heartily agree with the opinion of the reviewer, that ‘‘ it would be an immense gain if every name proposed to be altered had to pass through a regularly-constituted committee of investigation before it was accepted and allowed to pass current.’’ In such a committee, besides priority, two other paramount scientific interests should be consulted, and they are—continwity and authority. HEIDELBERG, November 1. C. R. Osten SAckeEn. @liS aes UeAmEe aye a WILLIAM KINSEY DOVER, F.G.S. We have to record the death of an old friend, and brother geologist, Mr. William Kinsey Dover, F.G.S., who died at Low Nest, near Keswick, on the 27th of March, 1891, in his seventy- fifth year. After completing his education, Mr. Kinsey was for some years engaged in mercantile pursuits, but he left London in 1855, and entered the Cumberland Militia, in which he served as Ensign (1855), Lieutenant (1861), and Captain in 1865. On his retirement from the Militia in 1868, he devoted himself to Natural 48 Obituaries—Sir A. C. Ramsay—Dr. F. von Roemer. History pursuits, and more lately to paleontology, paying especial attention to the fossils of the Skiddaw Slates, which he collected with great diligence and care, accumulating in time a very fine series of these rare Ordovician treasures. Mr. Dover was elected a Fellow of the Geological Society in 1880, and a member of the Geologists’ Association in 1881, taking part in the Lake-District long-excursion of the latter body in that year, as one of its directors. In 1890 Mr. Dover presented his fine collection of Skiddaw Slate Fossils to the Woodwardian Museum, Cambridge, where it forms a most valuable contribution to our knowledge of the Geology and Fauna of the Lake- District rocks. SIR ANDREW CROMBIE RAMSAY, Knr., ELD ib Rsop iGo. Born 1814. Diep Dscemper 97H, 1891. We regret to record the death of Sir Andrew Ramsay, late Director-General of the Geological Survey, which occurred at his residence, Baumaris, Anglesey, Dec. 9th, 1891, in his 77th year. He was educated at Glasgow, and was appointed to the Geological Survey of England and Wales in 1841, and became Local Director in 1845. He was nominated Professor of Geology at University College in 1848, Lecturer on Geology at the Royal School of Mines in 1851, and was President of the Geological Society in 1862 and 1863. He was elected a F.R.S. in 1849, and Knight of the Order of St. Manrice and St. Lazarus in 1862, and was elected an honorary LL.D. of Edinburgh in 1866. He received the Wollaston Gold Medal from the Geological Sociey in 1871. On the death of Sir Roderick JI. Murchison, Bart., he was made Director- General of the Geological Survey of the United Kingdom, and of the Museum of Practical Geology in 1872. On his retirement from these offices in 1881, he received the honour of Knighthood. He presided over the meeting of the British Association at Swansea in August, 1880. He was an Associate of many foreign societies. Sir Andrew Ramsay is author of ‘The Geology of Arran,” “Geology of North Wales,” 1858, 2nd edition 1881; “Old Glaciers of North Wales and Switzerland,” 1860; the ‘Physical Geology of Great Britain,” 1878; and of very many memoirs, chiefly on theoretical geology. His life and portrait appeared in the GroLocicaL Macazrine for 1882, Decade I]. Vol. IX. pp. 289-293. Dr. Ferpinanp von Roemer, Professor of Geology and Paleon- tology in the University of Breslau, whose Jubilee as Professor it was intended to celebrate on 10th May, 1892, died at Breslau, on the 14th December, 1891, in his seventy-fourth year. Dr. Roemer was elected a Foreign Member of the Geological Society in 1859, and was awarded the Murchison Medal in 1885. We shall give a notice of this distinguished Geologist in the February Number.— Epir. Grou. Mae. Geol Mag 1892. Decade II Vol. IX PLM ts i\Chapman del. GM Woodward Lith. West,Newman imp. New Gault Foraminifera. THE GEOLOGICAL MAGAZINE. NEW SERIES. DECADE III. VOL. IX. No. II.— FEBRUARY, 1892. ORLGINAL ARTIECLIHS. ——>—__ I.—NotE on AN IcuaNnopont TootH FRoM THE LowER CHALK (“TotreRNHOE Stone”), NEAR Hrrcarn. By E. T. Newton, F.G.S. TH\HROUGH the generosity of Mr. W. Hill, the Museum of Practical Geology possesses a tooth found in the ‘Totternhoe Stone” in the neighbourhood of Hitchin, which is of especial interest inasmuch as it is undoubtedly closely related to Iguanodon, and is of later date than any British Dinosaurian remains hitherto recorded ; the Acanthopholis horridus of Prof. Huxley,’ from the Chalk Marl, and the Trachodon (Hadrosaurus) Cantabrigensis, of Mr. Lydekker,’ from the “Cambridge Greensand,” being, up to the present time, the most recent of known British Dinosaurs. Remains of allied forms, however, have been found at a higher horizon of the Chalk of Maestricht, and have been described by Prof. Seeley,* and M. L. Dollo.* EXPLANATION OF FIGURES. A. Iguanodont tooth from the “Totternhoe Stone’’ near Hitchin. Enamelled surface. Enlarged twice nat. size. B. Same tooth, seen in profile. C. Portion of crenulated edge. Enlarged ten times nat. size. The specimen to which attention is now directed is the upper part of the crown of an unworn tooth, in an admirable state of preservation ; its lower part was evidently broken away before it was imbedded in the Chalk, and the sharpness of the fractured edges, as well as of the denticulations, shows that it has under- 1 Gron. Mag. Vol. IV. 1867, p. 65. 2 Q.J.G.S. vol. xliv. p. 47. * Q.J.G. S. vol. xxxix. p. 246. * Bull. Mus. Roy. Hist. Nat. Belg. vol. ii. p. 205, 1883. DECADE IIIk—yVOL. IX.—NO. II. 4 50 E. T. Newton—Iguanodon in the Lower Chalk. gone no subsequent attrition. The greatest length of the portion preserved is about 0:6 inch, and its width from before backwards 0-5 inch, whilst the greatest thickness, at the fractured end, is about 0-4 inch. The enamelled surface is somewhat pointed at the apex, and has a single crest, extending from top to bottom, which divides this surface into two unequal areas. The anterior and posterior margins are ornamented with strong serrations, from which grooves extend, almost vertically, some distance on to the enamelled surface. When viewed from before, the crown is wedge-like, and the serra- tions of the edge, when seen with a lens, are found not to be simple, but each of them is itself denticulated, giving a mammillated appearance to the somewhat thickened edge. The enamel is slightly roughened by small vermiform ruge. The close resemblance between this tooth, so far as preserved, and some of those figured by Sir R. Owen! as Iguanodon Mantelli, would lead to the inference that it belonged to the same species were it not that one of these (figs. 15, 16) having only a single ridge on the enamelled surface, has more recently been referred by Prof. Seeley * and Mr. Lydekker® to Trachodon (Hadrosaurus), and as our specimen has only a single ridge, it would seem, at first sight, that it also should be referred to Trachodon. However, Sir R. Owen’s figures 10 and 17 have only small secondary ridges of the enamel, and these do not extend far from the base of the tooth, our specimen therefore might well be a portion of such a tooth with the small ridges broken away. Besides this, another tooth with only a single enamel ridge, which is from the Wealden, is called Iguanodon by Sir R. Owen,* and no one seems to have questioned the correctness of this determination. Then, again, with regard to the serrations, these are coarser than in the figures of T’rachodon,’ and the grooves extend from them some distance over the enamelled surface, a character seemingly wanting in Trachodon. The mammillations of the serrations find their counterpart in both Iguanodon Mantelli and Trachodon (Hadrosaurus) Foulkei. The Dinosaurian remains from the Maestricht Chalk described by Prof. Seeley and M. L. Dollo inelude certain bones which are said to have affinities with Iguanodon and Hadrosaurus ; they have been named Orthomerus Dolloi. It is possible that the tooth from the “Totternhoe Stone” may prove to belong to the last-named genus ; but as there is no evidence at present of the teeth of Orthomerus, it would scarcely be wise to refer our specimen to it ; on the other hand, it is quite certain, that in whatever genus this tooth may eventually have to be placed, it is very closely related to Iguanodon, and with this it will provisionally be included, and named specifically after its donor Iguanodon Hillit. 1 Pal. Soc. Cret. Rept. suppl. ii. pl. vii. figs 10, 15, 16, 17. 2 Q.J.G.S. vol. xxxv. p. 591, 1879. 8 Q.J.G.S. vol. xliv. p. 47, 1888, * Pal. Soc. Rept. Wealden, pt. ii. pl. xviii. fig. 6, 1855. 5 Leidy, Smithsonian Contributions, vol. xiy. 1865. E. T. Newton—Onychodus in the Old Red of Forfar. 51 II.—Nors on A New Species oF OvycHoDUS FROM THE LowER OLD Rep SanpstTone oF ForFar. By KE. T. Newron, F.G.S. Te occurrence in the Ledbury ‘“ Passage-beds”’ of a united series of teeth referable to the American type of fossil fishes named by Prot. Newberry Onychodus, was made known by Mr. A. Smith Woodward in the Grotocicat Magazine for November, 1888; and in the British Museum Catalogue in 1891. Since then I have met with another example of the genus among the stores of the Geological Survey, which, as it seems to be quite distinct from the Herefordshire species, and is from a distant locality, deserves to be placed on record. Onychodus scoticus, n. sp., from the Old Red Sandstone of Forfar. Presented to the Museum of Practical Geology by James Powrie, Esq., F.G.S., of Reswallie. The specimen consists of a series of teeth from the Lower Old Red Sandstone of Turin Hill (?), Forfar, and has been presented to the Museum of Practical Geology by Mr. James Powrie, of Reswallie, who has done so much to extend our knowledge of the fauna of these rocks. This series of teeth, is preserved in a shaly layer covering a small block of hard grey sandstone ; and the shale having been split open, the fossil itself has been broken through from end to end, one half being retained in each piece of shale; portions of some of the teeth, however, have fallen out. There are eight teeth placed one before another in a single row, with their bases codssified so as to form a rigid semicircular base, which measures about 9 mm. in a straight line from end to end. Two of the teeth seem to have been quite perfect when imbedded in the shale; but the others are more or less worn down and rounded. The longest and most perfect tooth is about 4 mm. in length; and the shortest nearly 3 mm. The basal portion, so far as one can judge from a 52 F. Chapman—Gault Hyaline Foraminifera. wax impression, is about 2 mm. wide. Each unworn tooth is strongly curved, or rather crooked, with an acute somewhat re- curved point. The concavity of each tooth is directed towards the end where they are least worn. The cavities, left by the teeth which have fallen out, show that these teeth were provided with a very distinct ridge on each side, and they appear to have been flattened from before backwards. An examination of the broken surfaces with a lens reveals a very vascular condition of the base, and large vessels pass from this into each tooth. No division can be traced between the bases of the teeth, which are evidently firmly united to each other. Compared with Onychodus anglicus and O. arcticus, the present specimen differs in the more uniform size of its teeth, the longest of which is not half the length of the most perfect tooth in the former species, from which it also differs in the greater curve, and non-involution of the base; and further, its teeth have distinct lateral ridges and no central cavity. The uniform size of the teeth in the Forfar specimen agrees better with the American forms, but they are much smaller than in any one of the three species described by Prof. Newberry, and are of a different shape. In O. Ortoni the teeth are said to be sunk in the base ‘‘as posts are planted in the ground.” British examples of this genus are so rare that even such frag- ments as that above described may well receive specific distinction, and I propose to name it Onychodus scoticus. The following are the species of Onychodus now known :— O. sigmoides, Newberry. Corniferous Limestone (Lower Devonian), Ohio. Monog. U.S. Geol. Surv. vol. xvi. p. 56, 1889. 0. Hopkinsi, Newberry. Chemung Group (Upper Devonian), Delaware Co., New York. Ibid. p. 99. 0. se ae Huron Shale (Upper Devonian), Franklin Co., Ohio. ta. P. ° 0. anglicus, Smith Woodward. Lower Old Red Sandstone Passage Bed, Ledbury, Herefordshire. Gxrot. Maa. Vol. V. 1888, p. 500, and Cat. Foss. Fishes, Brit. Mus. part 1, p. 393, 1891. O. arcticus, Smith Woodward. Lower Devonian, Spitzbergen. Grou. Mae. Vol. VI. 1889, p. 499; and Ann. Mag. Nat. Hist. vol. viii. 1891, p. 1. O. scoticus, Newton. Old Red Sandstone, Forfar. II].—Some New Forms or Hyatine ForamMIniFEeRA FROM THE GAULT. By Freperick CHAPMAN. (PLATE II.) N the course of investigations amongst the Microzoa from the Gault of Copt Point, Folkestone, some Foraminifera came under my notice, which are hyaline representatives of the usually arenaceous type Webbina. These forms are remarkably similar in external appearance to those of the arenaceous group, but microscopical examination of the test under a high power reveals the finely tubulated structure characteristic of the hyaline type. It must, however, be borne in mind that the isomorphous genera in the three groups of the Foraminifera based upon shell-structure 3 (Si) F. Chapman—Gauit Hyaline Foraminifera. are of classificatory rather than biological value; it being most probable that the same organism may possess the ability to form the structure of its external covering according to the conditions under which the Rhizopod exists. Dr. Sollas has described! two forms of Hyaline Foraminifera from the Cambridge Greensand under the generic term Webbina, which presents the same finely perforated structure as the Gault specimens, and he has proposed to reserve the generic term Webbina for the type he describes’ possessing the perforate character. The structure of the shell wall of these perforate varieties, as Dr. Sollas points out, shows the type to be closely related to the Rotaline Foraminifera: and since there is present a shelly flange which may possibly be equivalent to the keel-like edge of some Pulvinuling, I would therefore suggest that the perforate varieties of Webbina might form a separate genus, which would find a place between Rupertia and Pulvinulina. Another somewhat remarkable form found is interesting on account of the prominence which it gives to the fact of the great variability of the Foraminifera. This is an adherent and ramifying variety of Polymorphina. In general appearance it somewhat resembles the form Sagenella of Dr. Brady, especially in the shape of the terminations with their simple apertures. In a few specimens. however, the portion of the test, which is rounded and inflated, and is much smaller than the ramified portion, shows a decidedly chambered structure, identical with that of Polymorphina ; and this is confirmed by one individual of which the test was broken, showing the chambered portion. The cervicorn and fistulose varieties of Polymorphina are very fully discussed in Messrs. Parker, Jones, and Brady’s paper on the genus Polymorphina ;* under the name of Polymorphina Orbignii, Zborzewski, sp. Vitriwebbina, gen. nov. PI. II. General characters.—Test opaque to translucent, of a whitish or pale-brown colour. Shell-wall very finely perforated. Consisting of a single hemispherical or pyriform chamber, or of a graduated series disposed usually in a curved line, and adherent upon some foreign substance. The chambers are connected by stolon tubes, very distinctly seen on the under surfaces of the specimens which have become detached. The surface of the shell may be smooth, pitted, or, as in Dr. Sollas’s specimen, tuberculate. Vitriwebbina Sollasi, sp. nov. Pl. II. Figs. 1-8. This form consists usually of one, but sometimes of even four pyriform chambers, always adherent, in many cases to rolled fragments of phosphatic nodules. The test is usually white, though sometimes pale-brown and opaque, and the shell-wall is finely tubulated, with the exception of a thin encircling flange of shell material as it were completing the fusion of the shell to its attach- ment. This peculiar flange of shell substance is present in Dr. 1 Grou. Mac. Dec. II. Vol. IV. 1877, p. 102-105, Pl. VI. - 2 Trans. Linn. Soe. vol. xxvii. 1870 (1871), pl. xlii. figs. 38 a—o, pp. 244-248. 54 H. H. Howorth—Abscence of Glaciation in Sollas’s specimens, but turned inwards on the foreign body. This variety occurs in Price’s Zones I. III. V. VII. and XI. at 20 feet from the top of the Gault, at Copt Point. I have also since found it in the Gault at Battlebridge, Merstham, Surrey. I have associated the name of Dr. W. J. Soilas with this form, who first described the perforate type. Vitriwebbina levis, Sollas, sp. Pl. II. Fig. 4. This form has already been recorded by Dr. Sollas, and is mentioned here in passing as occurring in the Gault beds of Folke- stone in Zones LY. VII. and XI. at 50 feet from the top. Polymorphina Orbignii, Zbor. sp., cervicornis var. nov. Figs. 5 and 6. The test, which is generally found attached to shell fragments, such as Nucula, commences with a polymorphine arrangement of chambers, which proceeds to take on a wild flattened fistulose growth, sometimes six times the length of the initial series of chambers. The apertures are simple orifices at the terminations of the branchlets. An example occurs in which the branching growth has just commenced. This variety is found in Zones III. and VII. of the Gault at Copt Point. In concluding these notes, I wish to acknowledge the kind advice I have received from Prof. T. Rupert Jones, F.R.S., and also the valuable assistance of my friend Mr. C. D. Sherborn, F.G.S. EXPLANATION OF PLATE II. Fic. 1.—Vitriwebbina Sollasi, sp. noy., showing thin encircling flange f (Xx 60). » 2.—V. Sollasi, fragment of test showing tubulate structure (x 360). », 3-—A specimen of ditto with four chambers (x 60). » 4.—V. levis, Sollas, sp. (x 40). », 9.—Polymorphina Orbignii, Zbor. sp., var. cervicornis, attached to a frag- ment of shell of Mwcula. The lines indicating the later growth are slight grooves in the shell to which the Foraminifer was attached, as if the foreign body were partially dissolved along the lines of attach- ment; p. represents the polymorphine series of chambers. The whole of the shell contains an infilling of pyrites (x 30). », 6.—The apex of one of the branches 01 P. Orbignii, var. cervicornis, showing the finely tubulated shell-wall. IV.—Tue Assence oF GriactaL PHENOMENA IN LARGE Parts oF Western Asta AND Eastern Europe, Eve. By Henry H. Howortn, M.P., F.G.S., ete. N some papers which you have done me the favour to print in the GronocicaL Macazing, I have endeavoured to apply a new touchstone to test the age of high mountain chains and of land of high elevation, namely, the presence or absence of distinct and pro- minent traces of former glaciation, and I have argued that where such traces are not forthcoming in a very unmistakable manner, we are justified in concluding that these highlands have been elevated since the so-called Glacial Period. I have endeavoured to apply the touchstone in question to the Ural and Altai Mountains, to the Thian Shan and Himalaya ranges in Asia, and to the great Cordillera which binds together the two continents forming the New ‘Western Asia and Eastern Europe, ete. 50 World. I wish to make my survey more complete by an examina- tion of an interesting area comprising Hastern Europe and South Western Asia. Before addressing myself directly to this issue, however, I feel under an obligation to reply to the criticisms of Mr. Blanford. They appeared when I was far away from England, or they should have had an earlier notice. In one of my papers I quoted the testimony of four geologists of wide-spread fame and great experience, keen and patient observers. whose works are geological classics, who had visited and explored with great pains the Urals, the Altai Mountains and the Thian Shan range, namely, Humboldt, Tchihatchef, Von Cotta, and Severtsof. All these observers had examined geological phenomena in many latitudes and were familiar with glacial marks, and all of them failed to find the footmark of the Glacial Period in the ranges in question, although they looked for them. This is assuredly a strong case. How does Mr. Blanford dispose of it? He says he can attach no value to the evidence brought forward, because (mark the phrase) ‘I myself was at one time led away by it.” ‘To measure the capacity of some of the greatest geologists of modern times for distinguishing what I venture to think are among the most obvious of phenomena, by the fact that the critic, like every other good man, has once made a mistake, seems to me to involve an appeal to other than scientific reasoning. Let me add that, as Mr. Seebohm has reminded me, Pére David, who spent many months at Moupin, on the frontier of China and Tibet, at the foot of a mountain as high as Mont Blane, failed to find traces of old glacial action there, a result which was, I believe, also reached by Richthofen in other parts of China. This is assuredly a very important addition to the strong chain of witnesses I have previously quoted in your pages in references to the great congeries of mountains in Hastern Asia. Turning to the Himalayas, Mr. Blanford does not dispute the fact that in Peninsular India and in the great plains of the Indus and the Ganges, the real Hindostan, no true glacial phenomena are forthcoming. He urges, however, that they do occur high up in the Himalayas on a scale quite incommensurate with my arguments. I have not visited the Himalayas myself, but I did quote two ex- perienced observers, Mr. Campbell and General McMahon, whose testimony is decidedly at issue with Mr. Blanford, and who had visited the country. It is true that some of Mr. Campbell’s theorzes are fanciful enough; but I never met any one who disputed his keen eye for, and his extraordinary knowledge of, glacial facts in all parts of the world. Apart from these explorers, however, I appealed to a witness who is unbiassed by our discussions, who has no views whatever as to the glacial theory. I mean the Sun. Mr. Blanford seems to have a contempt for photographs. I am bound to say I differ from him toto celo; and I have examined glacial phenomena over as much ground as most people. In regard to the main and most satisfactory evidence of glaciation, 56 H, H. Howorth—Absence of Glaciation in more satisfactory than either boulders or scratched stones or moraines, namely, the rounded and curved outlines always present when a glacier has polished a valley, I know of no testimony so excellent as that of photographs, for by their help we can rid ourselves at once of the personal equation of the observer whether he have ice or water on the brain. I appealed to photographs—many of which I had seen—and to that appeal I adhere. I contend they are a complete justification of my views. I never argued that when you get up into the higher valleys of the Himalayas there is no evidence of the former presence of glaciers. I emphatically stated that there is, as Hooker and others showed long ago; but I did and do contend that these traces of former glaciers are infinitesimal compared with what they ought to be if the Himalayas had existed when the great Rhone glacier was depositing its famous loads far and wide. I do not quite understand the reference to a difference of latitude which Mr. Blanford says I have overlooked. What has latitude to do with the question? Assuredly the Urals, which rise in places to a height of 1525 metres, and which are covered with snow for eight months in the year, the Altai Mountains, which are higher, and the Northern Rockies are all in latitudes which, if that had anything to do with the question, would. have placed them at least on the same level as the Alps, the Pyrenees, and the Scotch Mountains, which have such abundant traces of glacial action upon them. It is not latitude that has to do with the question, but an abundant supply of moisture, and a sufficiently powerful source of cold. With these two conditions there will be abundant snow and ice, whatever the latitude. When I spoke of a great Asiatic Mediterranean having existed during the Glacial period, it was not, as Mr. Blanford seems to suppose, to invoke an army of icebergs as having existed there, which I altogether disbelieve in ; but to point out that this reservoir of water close at hand would supply the very moisture necessary for a tremendous glaciation of the Asiatic mountain chains, and notably of the Altai, if these mountain chains had then existed. Granting this supply of moisture, granting the capacity of these high ranges as excellent condensers, we have in the wide area they cover the necessary elements for a huge development of ice. If there is no evidence of this ice having existed, then I would urge again that it goes a long way to prove that the great mountains did not exist either at the time in question. That the glaciers have been bigger no one disputes, but I hold with Godwin-Austen that this was comparatively recently. On this subject he wrote as follows in the Geological Journal many years ago :— “T have often been struck by the indications of considerable amounts of change of temperature within what may be called our own times. The proofs of this are to be found in many parts of the great Himalayan chain. These consist in the numerous terminal moraines which in so many places abut on the larger rivers, down to which - Western Asia and Eastern Europe, ete. 57 point glaciers must have once descended, and which in some cases must have rivalled in length the present ones of the Mustakh MAINES Gls. se bse Among the proofs that there has been a change of temperature of recent date are the following. Many passes which were used even in the time of Rajah Ahmed Shah of Skardo, are now closed. The road to Yarkand over the Baltoro glacier, which before his time was known as the Mustakh, has by the increase of the ice near the pass become quite impracticable. The men of the Braldoh Valley were accordingly ordered to search for another route, which they found in the present pass, at the head of the Punmah glacier above Chiring. Again, the Jussespo La can now be crossed only on foot; whereas in former times ponies could be taken over it. The pass at the head of the Hoh Loombah is now never used, though there is a tradition that it was once a pass; no one, however, of the present generation that I could hear of had ever crossed it. Certain large glaciers have advanced, such as that at Arundu, of which the old men assured me that in their young days the terminal cliff was 14 miles distant from the village. Mr. Vigne says, ‘it was a considerable distance,’ it is now only 400 yards. A like increase has taken place at Punmah, where, within the last six years, the road has been completely covered by the ice and moraine, and where Mahomed, my guide, told me the old camping ground was, now lies a quarter of a mile under the ice; the overthrown trees and bushes plainly testified to the recent advance which this mass has made; this evidence was equally well seen along the side of the Arundu glacier. Even so lately as twelve years since, the people of Shigar were enabled to get two crops off their fields; thus the first crop (barley) was followed as soon as eut by a second (kungtini), which ripened by the end of autumn. Since that time it will not come to maturity, so that after the barley the fields now lie fallow, and the kungtini has now to be sown earlier in the season” (Journ. Roy. Geog. Soc. vol. xxxiv. p. 51.) In regard to the shrinkage of the glaciers, evidence is not of the same kind, for the good reason that during recent years the stage has been one of growth, but the same author’s descriptions point to the traces of former extension as being comparatively recent. Thus he says of the Punmah glacier: ‘“‘This glacier has in some past years - been upwards of a 100 feet thicker than it now is, as shown by its lateral moraines, and the grooved and scratched rocks on either side” (id. 30). Again, speaking of the glacier of Biafo, he says: ‘The present thickness of the ice is a point not easily determined ; but, judging from striz in the sides of ravines from which glaciers have retired, from 800 to 400 feet, is not an exaggerated allowance for what they once have been” (id. 50). Speaking of Basho he says: “Glacier action of former times was here very apparent in the great masses of angular rocks above the village. The enormous collection of angular fragments in the terminal moraine of a large glacier, the remains of which are to be sought higher up, and where now it is only 4 or 5 miles long, with broad feeders from the mountains on the west side” (id. 54). This will suffice from Godwin-Austen. 58 H. H. Howorth—Absence of Glaciation in I might have quoted another witness. Jn a note to an admirable and most interesting work on Eastern Persia well known to me and to Mr. Blanford, and on page 470, I find the following: ‘My brother, Mr. H. F. Blanford, has suggested to me that the greater humidity of Persia and the neighbouring countries in former times may have partly accounted for the former great extension of glaciers in the North-West Himalayas. If the west wind so prevalent in North-Western India were moist, instead of being hot and dry, as it now is, there would be certainly a great increase in the deposition of snow on the Western Himalayan ranges.” Nay, I might have, as I have before, quoted Mr. Blanford against himself; for, in a paper on Persian superficial deposits, he argues that the drying up of Central Asia is connected with the elevation of the Steppe region of Central Asia (J.R.G.S. vol. xxix. p. 500). In this I completely agree. The desiccation of Central Asia is going on at this moment. We have a great deal of evidence about the shrinkage of its lakes and the disappearance of its streams in historic times. With this desiccation I hold the shrinkage of the Asiatic glaciers has also proceeded ; and we need not, especially if we are champions of Uniformity, go back beyond a reasonable date in order to find an ample and sufficient cause for the increased length of the Himalayan glaciers in recent times, Another point in Mr. Blanford’s criticism I do not quite follow. I understand him to say that because the Wild Ass and the Antelope can live now at great heights, the Rhinoceros could do the same. The Rhinoceros is essentially a tree-feeding and shrub-feeding animal, and does not graze on short grass; and we know the kind of trees which the Rhinoceros antiquitatis fed upon. To postulate that the Rhinoceros could live where the Antelope lives is to me, like saying that the Zebra could live where the Wild Ass of Mongolia lives; that Cape Buffalo could live where the Bactrian Camel lives ; and that the Bison could exist where the Musk Sheep thrives. I do not understand the argument: nor do I understand why the existence of a zoological sub-province in China, which has been established by a chain of observers from Brian Hodgson to Pére David, precludes the notion, otherwise so strongly supported, that the Highlands of Hastern Asia are a recent feature in physical geography. This, I] think, completes my reply to Mr. Blanford; and I will now pass on. My argument was not meant to be restricted to the great masses of mountains in Eastern Asia. These masses of mountain are closely united in their physical history with the highlands stretching from the Hinduh Koh westward through Persia; and it is a remarkable fact that there also we have a singular absence of erratic phenomena and of traces of a so-called Glacial period. On this subject Mr. W. T. Blanford says: ‘In Persia the country, although greatly elevated above the sea-level, is covered with drift ; but I found no signs of striation on the pebbles,” nor had he been able to detect glacial markings on extensive plateaux more than Western Asia and Eastern Europe, ete. 59 6000 feet above the sea, with peaks rising to 12,000 feet and even more (Q.J.G.S. vol. xxx. p. 478). Hlsewhere he says: “Of glacial action in Persia there is, perhaps, a trace in the thick gravel found locally, as near Karman, on ranges of considerable height. At the same time no clear evidence of ice action could be detected. In the Elburz Mountains, which are in about 36° latitude, neither Dr. Filippi nor I could find any evidence of former glacial action. It is true that neither of us had much opportunity for exploring ; but it is remark- able that Abich should have called attention to the same absence of glaciation in the Caucasus” (Blanford’s Eastern Persia, p. 470). Dr. Filippi, whose memoir is before me, speaks in the same terms. He very naturally asks where the great mass of water can have come from to spread the gravel which occupies so much of the sur- face of Persia, to explain which he says we must not have recourse to a glacial epoch of which there is no trace in the Elbwrz Mountains, “ di cui non vha nelle montagne dell’ Elburz alcuna traccia” (Atte della Soe. It. de Sci. Nat. vol. vii. p. 283). The same writer calls attention to another fact which I would quote here, and which corresponds with what I have said of the Ural Mountains and the American Cordillera, namely, that these great masses of high land form no zoological frontier, and are therefore presumably of very recent origin. “A great continuous barrier,” he says, “like this, ought, like the other principal mountain chains of the world, to form a frontier separating two sensibly distinct faunas, but this is not the ease. There is a greater difference between the fauna on the two sides of the Alps, and on the east and west of Hurope than on the two sides of the Elburz” (id. 279-280).. He further urges that the fauna of the high ground in Western Persia is essentially that of the Caspian depression and of the Turanian Steppes, which seems to me to also point to these highlands having been elevated very recently. No doubt Mr. Palgrave, who by the way was not a geologist, did profess to find considerable traces. of old glacial action in the neigh- bourhood of Erzerum, as others have professed to find them in the Caucasus. In answer I would refer to the observations of a most acute and experienced geologist, namely Abich. In an elaborate memoir by him on the geology of the Caucasus and the mountains of Armenia and North Persia, published in the 7th volume of the Memoirs of St. Petersburg Academy, he says: “The distribution of erratic blocks, together with the associated phenomena of the grinding and polishing of rocks, is foreign to the Caucasus. Nevertheless, large blocks of stone and masses of rock of large dimensions, like erratic blocks in many respects occur in some of the valleys, especially those of the Terek ; often too they have travelled some distance. But the transport of these blocks has nothing in common with the true diluvial phenomena of the period of erratic blocks of the European mountains, but is assignable merely to alluvial action which still operates, though in a diminished man- ner.” He describes how, through the conformation of the valleys, especially in such places as the narrow pass of Dariel, great barriers of debris are found which dam back lakes 200 or 300 feet deep, and 60 H. H. Howorth— Absence of Glaciation in when these burst their bounds, great masses of stone are carried along the Terek Valley as far as Wladikawkas. Abich mentions how the great earthquake in 1840 which destroyed the village of Arguri in the district of Ararat, was followed by a great rush of waters which bore along great masses of rock much larger than those now to be seen in the Terek Valley. Similarly, he says, great blocks of 250 to 300 feet in circumference have been carried from the district of Ararat for a distance of seven versts over an inconsiderable slope. Abich goes on at some length to show that the moraines and other glacial phenomena of the Caucasus are very local and confined to the upper valleys, and do not protrude out into the open country in the way they do in the West of Europe, and that they are the obvious handiwork of the existing glaciers, and do not point to a glacial period. I prefer to quote his conclusion in his own words. “So lage denn in diesen Moriinen des Gyoal Don, die einzigen von so bestimmten Charakter und solche Grosse mit in Kaukasus bekannt gewordenen, ein anniiherndes Maass fiir das Maximum des Gletscherwerkungen von, wie sie seit dem Begunt und dem Verlaufe der alluvialzeit bis zur Gegenwart, hier durch lokale mit der Entstehung des Kasbek zusammenhiingende physikalische Con- figuration der Kamm region bedingt worden, niemals aber das Privilegium einer besonderen etwa eine allgemeine erhdhete Gletscherbildung bedingenden, oder auch nur begiinstigenden Epoche fiir das Kaukasus gewesen sein konnen” (Mems. St. Pet. Acad. vol. vii. pp. 519-523). The same conclusions were arrived at by Mr. J. F. Campbell, whose wonderful appreciation of glacial phenomena is specially apostrophized by Professor Judd. As he neared the Kaspes peak, he says, “ We drove over undulating plains of clay and passed a lot of large stones; but I could find no scratches. In the evening I walked to the right bank of the river and found a great ridge of clay which I took for a moraine; but even here I could find no scratched stones. I believe it to be part of a delta, I sketched and inspected brick-pits, and reluctantly gave up my Caucasian glacial hypothesis... . . We drove up a beautiful gorge with well-marked terraces of rolled stones at the mouth of it, and with many very large stones scattered about; but I saw nothing glacial in the gorge.” Speaking of the route between Kazbeg and Tiflis, he says: “The outlines of the mountains are due to weathering. Except large stones I could find no trace of glacial action in the whole journey of 202 versts (1834 miles) .... After a careful search in the valley lower down than Zalkan all the large stones that I could find were smooth water-worn pebbles taken out of the clay and out of great beds of rolled stones which there make large hills... .. If ever glaciers worked in the range, their traces have been almost entirely obliterated. . . . . I could find no signs of glaciers even on the remnants of the old surface through which the water has dug a couple of thousand feet or more.” Speaking of the only lake in Daghestan, the water of which is dammed by a dam of angular gravel, which may be a terminal moraine, he says: ‘I could find no Western Asia and Eastern Europe, etc. 61 glaciated rocks anywhere about the lake. The moraine is the only mark of glaciation that I could identify in the whole range while travelling from end toend..... From lat. 40° to 45° N. long. 50° to 85° E. I could not find one rounded hill or hollow, one scratched rock or stone, one perched block, one lake-basin, certainly due to glacial erosion, a glacier, or the trace of one. The highest hills are jagged sierras, the lower hills pyramidal or scarped, the valleys of all sizes are shaped liked a V” (Q.J.G.S. vol. xxx. pp. 460-466). Let us now turn to another mountain-range, namely, that of the Lebanon in Northern Syria. Here Sir J. Hooker many years ago (Nat. Hist. Rev. Journ. 1862, p. 11) described the Cedars as growing on very considerable moraines, and this fact has been quoted in almost every manual of geology as evidencing the former glaciation of the Lebanon. The facts are, however, very doubtful indeed, and it is clear that in view of recent explorations they will have to be revised. In a paper by M. Louis Lartet published in the 22nd volume of the Bulletin of the French Geological Society, embodying his re- searches extending over several months in Syria and Arabia, he refers to these supposed moraines, and urges that they are not really moraines and do not belong to the so-called Ice age at all, in the first place because he had never seen any scratched pebbles or other traces of glacial action in the midst of these deposits, and secondly, because they contain no basaltic pebbles or boulders showing that they must be older than the outbreak of basalt, etc., which have left such marks on the country, and he identifies them with the calcareous conglomerates long ago described by Botta (Mém. de la Soc. géol. de France, 158) to similar beds described by Russeger in the Orontes Valley, also composed of conglomerates cemented to- gether by calcareous matter and which he treated as diluvian. Damascus is built on a similar bed, and it also occurs at the foot of Anti Libanus and on the eastern shores of the Lake of Tiberias (op. cit. p. 458). There is a similar difficulty about the supposed glacial beds in the Atlas range. Ch. Grad, who explored the range, found no traces of ice-action there (see Zeitschrift der ost Gesellschaft fir Meteorologie, 1873, p. 82). If we turn to Asia Minor, we shall naturally turn for geological information to the detailed and masterly work by Tchihatchef. He explored the peninsula with great pains, and he says emphatically that all the phenomena of the Glacial epoch are absent from Asia Minor, and he adds that this is very curious, since the climate of Asia Minor is even under present conditions considerably influenced by the cold of Russia (Tchihatchef, Asia Mineure, 4th part, Geology, part i. p. 485). Crossing the Bosphorus, we have the same testimony. Boué, in his great work on European Turkey, says distinctly that the phenomenon of erratic blocks is foreign to the two Turkeys, #.e. Asia Minor and Turkey in Europe, as it is in all the south-east of Europe (La Turquie d’Hurope, vol. i. p. 895). 62 H. H. Howorth—Absence of Glaciation in In an elaborate memoir on the geology of European Turkey, published in 1876, in the 20th volume of the Austrian Geological Society, F. Von Hochstetter quotes Viquesnel for the statement that neither in the Izker valley (vol. ii. p. 873) nor in that of the Rielska Reka above Rilo Selo (vol. ii. p. 374), nor in the upper Mesta valley (vol. ii. p. 366), do these deposits bear any resemblance to moraines. Hochstetter says, ‘‘I can confirm this view of Viquesnel,” and he goes on to show how easy it is sometimes to mistake a great mass of débris, the result of an avalanche, for a moraine, as in the case of a mass of granite blocks 10 métres high in the valley of Rielska Reka, and he concludes, “‘ Der Rilo, das héchste Gebirge der éstlichen Tirkei, hat ebenso wenig eine Getscherperiode gehabt, als der Balkan” (op. cit. pp. 460-461). Neumayr is equally emphatic, and I will quote a passage from his well-known Erdgeschichte, published in 1887 :—‘‘ No unmistakable traces of glaciation have as yet occurred in the Balkan Peninsula where they quite fail, except in the fact of the occurrence of some mountain Jakes which may point to glacier action in the Kilo Moun- tains in South-Western Bulgaria. I myself have explored several of the high districts in Greece, Thessaly, and Macedonia, and neither on the Shar-dagh, near Uzkub, nor on Mount Athos, nor on Olympus, nor in the AXtolian Alps, nor in the Korax Mountains, have I found any traces which can be attributed to the work of glaciers (op. cit. pp- 598-599). ; Moving northwards we have, in conclusion, to refer to the Carpathians. Traces of old glacial action have been diligently sought in this range, and more than one writer has described their existence; but they seem to be very local, if not doubtful. If they had been glaciated on a considerable scale, assuredly débris from their summits ought to be found dispersed over North Germany, which is literally covered with erratics that have come all the way from Finland and Scandinavia, where the mountains are for the most part very little, if any, higher. Neumayr says that traces of glacier action of any importance are only to be found in the upper Tatra, that mass of serrated granite heights which extends between the districts of Zips and Leptan in Northern Hungary and Galicia. Long ago Zeuschner found traces of the moraines of an ancient glacier at Zakspan in the Tatra group, and in later times similar traces have been found on the south side” (op. cit. pp. 597-598). Neumayr gives a good illustration of these mountains, in which I confess I can see no traces of the ice plane in the rugged angular masses of granite, and I very much doubt the character of these so-called moraines which are so obviously inconsistent with the rough rocks above them. I notice also that Neumayr points out as the most striking evidence of old glacial action in the Carpathians the presence there of many mountain lakes, which, following in the footsteps of Ramsay, he attributes to glacial causes, a view in which a large number of geologists cannot share. Turning to other parts of the Carpathians, Neumayr says quite Western Asia and Eastern Europe, ete. 63 frankly that though traces of glacial action are not entirely absent, yet they are insignificant (anbedeutend). In the Liptan Mountains, he says, are some uncertain traces; but he himself had failed to find any evidence over a considerable stretch of the Central Carpathians. Paul and Tieze had, however, noticed some moraines on the Cherna hora, the highest part of the Hastern Carpathians, 2007 metres high, whence the Theiss and White Pruth spring (id. p. 599). It seems to me that the evidence forthcoming to show that the Carpathians partook in the general glacial phenomena which have left such important and unmistakable traces in the much inferior ranges further west, such as the Vosges, the Morvan, etc., is quite unsatisfactory and insufficient, and that the problem should be again examined on the spot by some inquirers who do not mistake every heap of rolled stones for a moraine. It is incredible to me, if the Carpathians had existed in the Glacial age at the time when the mountains of Scotland and Ireland and Cumberland were loaded with ice, that we should have to search so minutely over them for any real traces of ice action, and to be actually limited to finding them on two or three of their higher peaks. The view that the further we go east in Hurope, the smaller do the traces of glacial action become, had already occurred to others. Penck says that Peschel was the first to observe (Volkerkunde, 1877, p. 43) that traces of glacial phenomena diminish in Europe as we go Hast. Of the three South German mountain ranges the Vosges present the greatest traces of glaciation, while in the Alps the intensity of the phenomena diminishes as we go East, and the Western Alps must have been more thickly covered with ice than the Eastern. The same is the case in America; only that there the intensity of glaciation diminishes as we go west. While the low- lying lands in the east of that continent were covered with ice, the mountain region on the west coast only harboured local glaciers (Penck, Vergletscherung der Deutschen Alpen, p. 438). The evidence seems to me to point to the Carpathians being a very recent feature in Kuropean physical geography, and, as in the case of the Balkans, the Taurus, in Asia Minor, the Caucasus (per- haps the Lebanon and the Atlas), and the Elburz Mountains, to their not having been in existence during the Glacial age, of whose unmistakable handiwork they bear no adequate traces. I have endeavoured in the recent papers which you have done me the favour to print to meet the demand of those geologists who have asked me for a cause competent to produce such a diluvial move- ment as I have postulated at the close of the Mammoth age, and which seems to be attested by a great mass of evidence. I have tried to collect a certain number of facts to show that at the close of the epoch in question there was a very violent and widespread dis- location of the earth’s crust, which led to the upheaval of some of its loftiest mountain chains. This upheaval was accompanied, as I believe, by an equally rapid and substantial subsidence in other places, of which also there is much evidence, some of which you 64 George Barrow—On certain Highland Gneisses. may perhaps permit me some time to print. It was in my view by a combination of these two movements that the diluvial phenomena to which I refer were produced. This cause is at all events an efficient one, and is therefore not like so many of the physical causes appealed to by the current school of Uniformity, both inefficient and transcendental. V.—On certain GNEISSES WITS ROUND-GRAINED OLIGOCLASE AND THEIR RELATION TO PEGMATITES. By Gzorce Barrow, F.G.S., H. M. Geological Survey. [Communicated by permission of the Director-General. ] N the course of my work in the Highlands of Forfar, I have been much struck with the mode of occurrence of certain light-coloured gneisses, of undoubted igneous origin. They are intruded into the surrounding rocks in an infinite number of thin bands or sills, generally interlacing, and often not more than two feet thick; sometimes not exceeding an inch. Their bulk in some areas exceeds considerably that of the older rocks, at other times it is far less. Two points are easily noted; first, they have no selvage edge; secondly, they have a very characteristic aspect, due to rounded grains of oligoclase. Commencing in an area where these characters are well marked, we find that the rock consists of oligoclase, muscovite, biotite, quartz, and microcline, but the last mineral bulks far less than the more basic felspar. It is the oligoclase that is so round-grained in form, and gives the rock its characteristic appearance. The micas, especially the muscovite, may easily be seen to have sharp angles. Gcing southwards, that is, away from an area where gneisses predominate, we observe the round-grained character to become less marked, and the oligoclase to form a smaller proportion of the whole rock. Still further south, the gneissose character becomes less marked, the oligoclase is further diminished in amount, while muscovite begins largely to exceed the biotite. In this phase the rock begins to be much permeated with coarse pegmatite, which forms a massive fringe to the southern edge of the gneiss, this fringe attaining in one case a breadth of 700 yards. The pegmatite consists essentially of microcline, quartz, and muscovite, the oligoclase being usually very small in quantity, and not visible to the unaided eye. That this rock consolidated much as we now see it is obvious from the vast area of contact meta- morphism that accompanies its intrusion. How then was it pro- duced? I learned the solution of the enigma from a normal granite. A common type of granite consists of potash-felspar, quartz, oligo- clase and two micas; the first-named mineral usually attaining the greatest size, and being most striking to the eye. But examine . George Barrow—On certain Highland Gneisses. 65 a broad dyke, belonging to the same original magma, and its appearance is seen to be very different. The potash felspar is no longer visible to the unaided eye, but it forms with the quartz a finely granitic matrix, in which the earlier crystals of consolidation, the two micas and oligoclase, are porphyritically embedded. Still further, if the rock is slightly decomposed, the latter mineral, somewhat tabular in form with conspicuous development of the clinopinacoid, is seen to have an outer shell, fairly well marked off from the much more rounded inner portion. The oligoclase obviously came up in this form, and completed its growth from the magma in which it lay, which later portion has been shown by Prof. Sollas? to be more acid in character than the core. The round-grained crystals then, of our round-grained gneiss, want their outer rim of later growth. How is this to be accounted for? If such a granite- magma be intruded during or towards the close of a powerful earth- movement, it may be forced, by the tremendous pressure, into every possible plane of weakness in the surrounding rocks. Now, obviously, it is not the crystals, but the liquid portion of the rock that must enter first, and all the crevices must be opened to the diameter of the oligoclase crystals before any of them can enter. The acid portion then of the magma, containing the constituents of potash felspar, must travel somewhat in advance of the crystals of earlier formation. In addition, the continuance of the pressure will still further force the liquid from the solid crystals, leaving at last just sufficient of the magma to fill the interstices between them. Thus, in my opinion, has the perfect form of round-grained gneiss been produced, which is by no means uncommon. The more acid magma will travel furthest, and finally consolidate as pegmatite. Put back the pegmatite into the gneiss, and you have the compo- sition of a normal granite. The round-grained character of the oligoclase is thus seen to be due to the draining off of the magma, from which it normally finishes its growth. To turn now to the question of the absence of selvage edges to the gneiss. Obviously a coarse-grained intrusion of an inch in thickness would only be possible if the country rock were nearly at the same temperature as the magma. There is further evidence tending to this conclusion, but as some parts of it are matters of dispute, it may be omitted for the present. From the foregoing remarks we may draw the conclusion that neither a round-grained gneiss of the above type, nor its accom- panying pegmatite, is in any true sense a metamorphic rock; both consolidated as we now see them. In addition, it would be more accurate to describe the pegmatite as being extruded from the gneiss, than intruded into it. The latter view implies a later date, while both are obviously of the same age. Like any other rock, such gneisses and pegmatites are liable to subsequent metamorphism. 1 See Prof. Sollas’ paper, ‘‘ Contributions to a Knowledge of the Granites of Leinster,’’ Trans. Roy. Irish Acad. vol. xxix. p. 427. DECADE III.—VOL. IX.—NO. II. 5 66 A. C. G. Cameron—Kellaways Beds near Bedford. VI.—On THe ContINvITY oF THE KELLAWAYS BEDS OVER EXTENDED AREAS NEAR BeEpDForD, AND ON THE EXTENSION OF THE FULLER’S HartH Works at Wosurn. By A. C. G. Cameron ; of Her Majesty’s Geological Survey.} [Printed by permission of the Director-General of the Geological Survey. ]} URING late years, by the opening of new sections, fresh information has been obtained of the geology of different parts of the country, and several fine excavations, the result of railway enterprise, have afforded great sections of the Kellaways beds in localities where only conceptions of them previously pre- vailed. Gaps have been filled up, and the continuity of the beds over extended areas confirmed. The principal revelations come from the Hull and Barnsley, and from the Swindon and Cirencester railways, opened respectively about 1881 and 1888, and the works now in progress in connexion with the widening of the main line at Oakley, near Bedford. There are records too of deep sinkings and borings, away from the outcrop, that indicate an area for the Kellaways as extensive as that of the Oxford Clay itself—and in the Midlands a more than usual thickness is reported; the Bletchley boring of 1886 specially indicating this. From Wiltshire to the bold cliffs of Gristhorp and Scarborough Castle, along the great sweep of Oxford Clay, this immense sand- bank—if it is such—is well enough indicated, and, when hidden beneath the Fens, the Humber flat, or the Drift, is unquestionably accounted for. Probably the earliest reference to the Kellaways comes from Boston, in Lincolnshire, where, in 1783,? the Oxford Clay was penetrated 470 feet, and then sand, to a depth of 8 feet, when the boring was abandoned as the water which then rose proved to be salt. About that time, too, William Smith observed at Kellaways Bridge, in Wiltshire, a stone being quarried for road-metal that “occurred in irregular concretions, the exterior aspect of which is brown and sandy, the interior being harder and of a bluish colour. It consists almost entirely of a congeries of organic remains. The beds of clay which cover this rock abound in selenite, and below are beds of clay again.” The late Mr. Bristow informed me that there is no Kellaways Rock now at Kellaways, it having been all quarried away at its outcrop, for road-stone, years ago. Local stones were much more used in olden times than now, owing to the difficulty of transporting road-metal; thus the rock at Kellaways was then used for that purpose. Briefly reviewing the past literature of this formation we find that, owing to the absence of sections along its course and the difficulty in consequence in tracing it, it was alluded to as being of 1 An abstract of this paper was read in Section C, British Association, Cardiff, 1891. 2 Phil. Trans, vol. xvi. p. 183 (1785). A. C. G. Cameron—Kellaways Beds near Bedford. 67 partial occurrence only, and, if not entirely wanting in the Midland districts, at least so attenuated as to be inseparable from the Oxford Clay. For reasons such as these the Kellaways were not known in Bedfordshire until of late years—nothing of the kind having been recorded ; the preponderance of yellow sand and loam on the sides of the valley around Bedford being looked upon as an extension merely up the slopes of the sand and gravel prevailing in the town. Large areas of building land have recently been covered with houses at Bedford, and there is a constant demand for bricks and lime. Brickmaking is carried on with energy, and the brickfields and stone-pits are prominent objects of interest in the neighbourhood of the town. Pits are opened at the outcrop of the Kellaways and earried down into Great Oolite through Lower Oxford (selenite clay), Cornbrash and purplish Cornbrash clay. In the making of bricks the Lower Oxford and the Kellaways loam or “lam earth,” as it is called, are mixed, lessening the liability in the clay to contract and crack in drying, as happens when the Lower Oxford, the ‘strong’ clay, is used alone. These Oolite divisions are seen to great advantage in the valley of the Ouse, as they lie upon each side of the river. Those extra- ordinary concretionary stones that characterize the Kellaways, jut out in the valley and stand about in some brickyard sections, in clusters, like gigantic fungi. There is an admirable display of these singular stones at Oakley Hill, near Bedford. The railway passes in a cutting there through a tongue of land that juts out into the valley from the amphitheatre of hills around, and the cutting which is now being widened and cut back towards the hills, has laid bare a considerable length of Upper Oxford, Kellaways rock and sand. The base of the Kellaways is not reached, but outcrops lower down with other underlying beds, round the flanks of the hill. Big stones, smooth and rounded, stand out in relief in the sides of the cutting, the effect being heightened by the softened aspect and sombre hues of the clay above. These also stood in rows upon the sand before being broken up, to make way for the rails. One of the workmen likened them to boulders put down for stepping-stones, adding that there must have been ‘a flood there at one time.” Some of these huge stones measure thirty feet in circumference. Where the sand is dug away and they stand each upon its own pedestal of sand, the resemblance to prodigous mushrooms is almost more than fanciful. Sometimes two stones are joined by a neck forming twin stones, when this semblance is lost in the figure of an hour-glass or the number eight. Where many stones are near together—and there are twenty or thirty now and then—these all but form beds of hard sandstone. In some cases they are isolated and bare on the bright yellow sand, and the mind reverts to the sea and the sands and the blocks of stone one sees there when the tide is out. Prof. Harker gives an account of the Kellaways beds exposed in the railway cutting at South Cerney, near Cirencester, and with these the beds at Oakley are identical. ‘The shelly bands in the Bedford 68 A. C. G. Cameron—Kellaways Beds near Bedford. sections have, however, a direct bearing on the concretionary origin of these stones, as set forth by Prof. Harker, that is not mentioned in his paper. The Upper Oxford and Kellaways beds in the Bedford sections are divided by a shelly calcareous band in contact with a shelly cap to the concretionary stones. Where this line is a broken one, there is no development of concreted rock below, and by gradations the Oxford Clay passes into silt and sand, seemingly indicating the piling up of the shells at particular spots as would happen on a shore exposed to strong currents; the subsequent decomposition of the animals resulting in the sand beneath being concreted into hard rock, as Prof. Harker says. The sand seems to have had deep water over it, as there do not appear to be any fossils whatever in it. On the other hand, the concretionary stones are—externally anyway, as Mr. Smith says, “‘congeries of organic remains.” All the animals, except the Belemnites, seem to have died young; Serpulg, so conspicuous on other Oolite shells, are entirely wanting. There are shelly bands wholly made up of Belemnites and Gryphea, while Ammonites, Avicule, and other forms besides, adhere to the upper surface of the doggers in great profusion. Pieces of this rock are more like Kentish rag than any other stone I know. A variety of Gryphea dilatata occurs in such abundance and so like Gryphea incurva in the Lias, that one would think the destruction of these beds could have contributed shells of Gryphea to the Drift, as easily as the Lias. Although a hard rock when dug at any depth, the Kellaways becomes rapidly friable and crumbles on exposure; and where these stones jut out naturally, the shelly cap is usually gone. There is an indurated seam of sandy marl above the shelly band at Oakley, which breaks into conical forms, exhibiting the structure known as cone-in-cone. The broad surfaces of these cones are upwards, ending against the Oxford Clay. I saw no instance of the apices pointing towards each other; and the whole series stand vertical in the stratification with the points downwards, or to the bottom of the seam. It is difficult, therefore, to conceive of these cones being due to the upward escape of gases —as suggested by Mr. John Young of Glasgow,’ although these would be emitted; the decay of the dead animals being sufficient to generate gases in the deposit whilst the bed was in process of formation. Throughout this seam the texture of the stone is more or less fibrous, and in the phenomena of the cones the fibres seem united into tufts, which taper downwards and end in a point; rather resembling some stalactitic infiltrations. The tract of land occupied by the outcrop of the different Kellaways beds, although of necessity only a narrow band, presents changes in the character of the soil marked enough to be known by distinct local names. 1 Grou. Mac. Vol. II. June, 1885, on Cone-in-Cone Structure. Abstract of paper read to Geol. Soc. Glasgow. A. C. G. Cameron—Kellaivays Beds near Bedford. 69 The long narrow sandy piece on the slopes that reach the Boulder-clay (and its breadth expands in places) is ‘white land,’ easily recognized even at a distance in dry weather, from its colour. Again, the zone next the white land, and between it and the stony (Cornbrash) soil, farmers and others call “lam earth” or loam. This is the horizon, too, in which the brickfields are opened. There is nothing in these soils, viewed agriculturally, to force the growth, and they are therefore almost useless for cropping; yet it is healthy grazing land, and cattle do well on it. Compared with other mild clays, the coldness of the “(lam earth” or silt is in excess. It is not unusual to find osier beds attached to the brickfields, and willows planted at particular spots where any considerable develop- ment of silt occurs ; in such cases osier beds thrive on the hill-sides equally well with those upon the water-meadows. Mention has been made of a saliferous rock in Bedfordshire, in the lower part of the Oxford Clay, yielding a saline water con- taining large quantities of salt. It is doubtful whether the true seat of this water is in the Kellaways or in the underlying Oolites. It seems, however, certain that the saltness is considerable where the Kellaways is thicker than usual. At the same time, even a larger quantity of chlorine existing in the form of common salt occurred where the water was obtained from rocks that underlie the Kellaways beds. The great value of our salt springs is for baths, and therefore the directors of an establishment in the educational centre from which I write, are to be congratulated on their recent discovery. There is no reason for ascribing any unusual thickness to the Kellaways beds of Bedfordshire ; nor any serious quantity of salt. I think myself that the ‘“‘sandy bed with big stones” is well known to well-sinkers in the clay districts as a trustworthy and palatable water-bearing stratum, beyond which they have no need to sink—that is for the requirements of any ordinary supply. The borings at Swindon and Bletchley, as a search for water, were failures; the water in both cases being very salt. Far down, however, in these bore-holes great developments of Kellaways beds were discovered under several hundreds of feet of clay. Concerning Swindon, the publications in 1886 (the boring was made in 1875) show the water to have come up from the Forest Marble, and it was near this horizon that the water at Bletchley was found. Notices of this boring appeared’ in connection with a report that the borers, after passing through the Oxford Clay, had come upon granite or granitic rock. Pieces of granitic rock did come, it appears, from these depths, but there is no proof that the whole of the thickness assigned to granite consisted of that rock. I passed all the samples myself as Kellaways sand and stone. It has, however, been suggested” that ' See Grou. Mae. Dec. III. Vol. IV. p. 139 (1887), Prof. Hull’s letter; Dec. WES Vol. VI. p. 856 (1889), A. Jukes-Browne, On the Occurrence of Granite in a Boring at Bietchley. 2 Grou. Mag. Dec. III. Vol. VI. p. 360 (1889), Granite in Boring at Bletchley, A. Jukes-Browne. 70 A, C. G. Cameron—Kellaways Beds near Bedford. the Kellaways beds beneath Bletchley may include granitic blocks and boulders embedded in the sand. The hardness of the Kellaways when dug at any depth might well account for the incessant pounding and tediousness in making this boring. Prof. Harker describes the Kellaways stone as ‘ obstinate,” blunting the chisel of the excavators, and resisting any forces but dynamite and gunpowder. Should other borings afford no further information, Granite in the Bletchley Boring will remain unique in our local geology, and justly excite much wonder. North of the Humber, where the lands bulge out at Drewton-on- the-Wolds and overlook the Humber flat, there is a greater thickness of Kellaways sand than has been observed throughout the central plain of England. At the Drewton cutting of the Hull and Barnsley railway, there is a tendency throughout of the sand to consolidate. 3ig boulder-like stones are not, as before, the most prominent feature, being replaced by blocks of tough siliceous sandstone weathering out in planes amongst the softer beds of sand. Above are fossiliferous beds of hard ferruginous sand, giving a very brown and irony look to this eutting. From this point northwards the rocky character of these beds is maintained, and the Kellaways, if lacking in the peculiarities developed in the south, leave England with importance on the Yorkshire coast. Since writing the above paper I see that Conybeare and Phillips, in describing the Lias, state that “irregular beds consist of fibrous limestone and cement stones (septaria), so called because used in imaking Parker’s cement. Where the fibres are not parallel to each other, they often form that irregular substance so common in the Coal-measures, to which an organic structure has often erroneously been attributed and termed the cone-in-cone coral.” } OBSERVATIONS ON THE Extension oF THE FuLLER’s Earta Works, AT Wopurn SanDs. Fuller’s-earth possesses remarkable grease-absorbing and cleansing properties, which places it foremost amongst the list of mineral detergents. The water thrown out by this formation is very soft and pure, and blocks of the earth have been placed in wells to purify the water. A superior quality of Fuller’s-earth is procured trom the Lower Greensand at Apsley Heath, in Bedfordshire. - Until lately the means adopted to work this mineral consisted simply of cylindrical holes in the sand, called “earth wells,” or merely “ wells,’ dug down to the Fuller’s-earth, and without lining of any sort, and of these there were but two. The operations now in progress bid fair, however, to give rise to no small stir in the place. On the brow of this hill are the offices of the Fuller’s-earth Company, with kilns for drying, and grinding mills used in the preparation of the earth. Sinking and shafting and the laying-out of underground works are carried on; and the little waggons with 1 Outlines of the Geology of England and Wales, p. 264 (1822). Major-Gen. MacMahon—Nature’s Manufacture of Serpentine. 71 their loads of “earth” are gliding up and down the steep hill-side. Apart from its being a source of wealth and industry in the country, this extension at Woburn of the Fuller’s-earth works is an interesting item in Bedfordshire geology, and the borings will determine probably the general arrangement of this mineral, regarding which, up to the present time, no particular notice has been taken. VII.—Tuer ManvuractureE oF Serpentine IN Nature’s LABORATORY. A Repty. By Major-General C. A. MacManon, F.G.S. ROF. BLAKE, F.G.S., President of the Geologists’ Association, has been good enough to send me cuttings from his recently published work “ Annals of British Geology ” containing his running comments on papers by me published during the period embraced by his volume, and for which I desire to tender him my best thanks. I think it will be more courteous on my part to offer a few obser- vations by way of reply to Prof. Blake’s criticisms than to allow them to pass in silence; but I must confine myself to one paper, by way of sample. I select that bearing the title at the head of this communication (published in the Proc. Geol. Assoc. vol. xi. p. 427), as the subject discussed in it is of general interest to geologists. The first extract from the Annals of British Geology I select for comment runs as follows :— «He then enters into the chemical question, and explains how carbonic acid will decompose silicates of magnesia and iron. The principal mineral altered being olivine, he shows that if from 2 molecules of this (MgFe), Si,O,, one molecule of ferro-magnesian oxide is removed, Mg FeO, and two molecules of water added, H,0,, we get Serpentine, H, (MgFe), Si,O,, but ‘as this involves an increase of volume some silica may also be removed.’ This last suggestion will, of course, alter the above, and bring it into harmony with the method suggested by Roth, as quoted by Teall (Brit. Petrography, p. 106), z.e., 5 molecules of olivine=10 MgO+6 SiO, — (4 Mg O+Si 0,)+4 H,O=6 Mg 0,44 Si 0,44 H,O=2 mole- cules of Serpentine.” , The sentence ‘as this involves an increase of volume some silica may also be removed” is marked by inverted commas and professes to be a quotation from my paper. Prof. Blake employs inverted commas, apparently, in order to convict me of a blunder out of my own mouth; the word “also” implying that some silica may have been removed from the two molecules of (MgFe) O,° Si O, in addition to the molecule of ferro-magnesian oxide; and as the loss of this silica is not shown in my account of the two molecules of olivine, my calculation must be wrong. Strange to say, the passage quoted under inverted commas does not occur in my paper. Not only did 1 not write the sentence given as a quotation, but it involves a serious misrepresentation of the views expressed in my paper. 72 Major-Gen. MacMahon—Nature's Manufacture of Serpentine. What I actually said is as follows: ‘As the above change [viz. the conversion of two molecules of (Mg Fe) O,. SiO, into H, (Mg Fe), Si,O,] appears to involve an increase of volume, I think it probable that the passage of carbonated water through olivine results in the removal of some of the ferro-magnesian silicate [ viz. Olivine] (without conversion into serpentine) in the form of soluble silica and carbonates.” My argument then was this: Olivine is a silicate of magnesia and iron. Its conversion into serpentine involves hydration and an increase in volume; it is therefore pro- bable that a portion of the olivine is removed without conversion into serpentine in the form of soluble silica and as carbonates of iron and magnesia. My account therefore (to borrow a book-keeping term) ~ only applied—and I thought that was sufficiently evident—to that portion of the olivine that remained behind and suffered conversion into serpentine. Suppose a parent gives a gold sovereign to his son but at the same time takes back from him five shillings in silver; what would be said of his logic if the parent subsequently called upon his son to render an account of his expenditure, and proceeded on the assumption that the boy had spent twenty shillings of his parent’s money on ‘‘tuck”? Would not the boy be right in saying, “‘ Why, I gave you back five shillings, and I have only to account for fifteen!” Yet the parent’s position in my illustration is Professor Blake’s position with reference to his criticism on my paper. I have humbly tendered my account of the fifteen shillings—straight and square—but Prof. Blake says, in effect, ‘That is all very fine, but your account of the fifteen shillings must be wrong, because you admit having given us back five shillings out of the sovereign!” Those are not his words, but that is what his criticism comes to. In another part of his abstract Prof. Blake writes as follows :— “The entrance of water into permeable rocks is easy to under- stand, but beyond this, it finds its way into the heart of the hardest minerals. The writer introduces Boscovitch’s theorem, that molecules within a certain distance have a repellant rather than an attractive force, in order to show that there must be molecular interspaces in minerals. Since the alteration of these minerals begins sometimes in the centre, when the channels through which chemical constituents have been abstracted or introduced are too small to be revealed by the microscope, he thinks they must have come in by these invisible pores [in which case, why do they not alter the outside as they pass by ?].” The objection raised by Prof. Blake is one easily met. Now-a-days, when we can not only study thin slices of rocks under the micro- scope, but also isolate the minerals of which these rocks are com- posed, and subject them to chemical analysis apart from the mass of the rock, petrologists have come to recognize the fact that a gradual change, more or less pronounced, frequently takes place in the chemical constitution of the uncrystallized magma during the gradual cooling and consolidation of an igneous rock. Some minerals crystallize in advance of others, and in doing so withdraw Major- Gen. MacMahon—Nature’s Manufacture of Serpentine. 73 from the magma a lion’s share of some of the chemical constituents. It may be a selfish thing to do, but, in this sense, some minerals are habitually selfish. The usual rule is that the more basic minerals separate first, and consequently those last formed are more acid than the minerals of the ‘first generation.” Owing to the progressive alteration of the magma brought about from the above cause, a gradual change in the composition of minerals of slow growth may, and often does, take place in the course of their formation; and this modification is marked by corresponding changes in their physical characters, such as colour in transmitted light, and optical properties. Hence what is known to microscopic-petrologists as zonal structure is commonly observed in the minerals of certain rocks—a structure so marked that it sometimes carries with it a progressive change in the angle of extinction from the centre to the periphery of the crystal, indicating in extreme cases a change in the mineral species. Now where, as explained above, the magma becomes more and more acid as comparatively basic crystals separate out from it, the centre of a mineral of slow growth would be more basic than its peripheral portions; and the centre would be more susceptible to the attacks of aqueous agents than the periphery, because the more basic a mineral is, the more readily it succumbs, as a rule, to ordinary corrosive agents. Variations from the normal type are even more common in the mineral than they are in the animal world, and a very slight difference, no matter from what cause it may arise, in the compo- sition of one crystal as compared with that of another of the same Species, or in one part, as compared with another part, of the same crystal, may suffice to give temporary immunity from the attack of a highly dilute acid. The corrosive agent makes for the weak spot, and exhausts itself on the material there before it attacks the less susceptible material in other places. Hence we often see in the examination of thin slices of rock under the microscope, that whilst one olivine has been more or less completely converted into serpentine, another by its side has been left untouched ;. and whilst part of a crystal has been converted into the hydrated mineral, the rest has successfully resisted conversion into serpentine. Had the process not been arrested, the less tractable olivines would ultimately have been conquered. In view of the above facts, if we grant that water can find its way through the pores of a mineral, I see no difficulty in understanding why the central portions of some minerals should yield to water charged with carbon dioxide, or other chemical reagents, before the peripheral portions. I have not alleged, however, in my paper, that the central portion is always the first part attacked. I wrote:—“ This alteration does not always begin at the outside of a mineral, and every microscopic petrologist will be familiar with cases in which it has been set up at the heart, and in the internal tissues—so to speak—of a mineral, and when the channels through which chemical constituents have 74 Major- Gen. MacMahon—Nature’s Manufacture of Serpentine. been abstracted, or have been introduced, are too small to be revealed by the microscope.” As a matter of fact, the alteration sometimes begins from the outside. In cases in which an olivine is perfectly homogeneous in chemical composition, one would expect this to be the case—the attack begins from the outside, and works its way slowly and gradually into the interior through “planes of easy solution,” or any other planes of weakness, that may exist. When there are actual cracks, the liquid reagent is not too proud to avail itself of the aid afforded by them in the work of sapping its way into the heart of the fortress. As for the question whether water under pressure, and under the conditions that obtain below the surface of the earth, can penetrate into the inner pores of a mineral, I must refer the reader to my paper under discussion, and to the instructive papers by Prof. J. W. Judd, F.R.S., on schillerization and kindred subjects. “ We must never forget,” he writes in one of his papers,! ‘that in the deep- seated rocks . . . . the whole mass, crystals and base alike, must be permeated by liquids and gases.” Cracks we can see under the microscope readily enough, and no petrological microscopist is likely to ignore their existence or the part they play in the circulation of underground waters. I likened them in my paper (p. 431) to the small veins and arteries in the human body; but we want some- thing in the mineral world to correspond with the minute capillary pores through which blood finds its way between the ultimate cells of which the animal body is built up. We cannot see the atoms, or even the molecules, of which minerals are composed; but we can infer the existence of molecular interspaces, an@ we can assure ourselves of the fact that water, under pressure, actually finds its way into these molecular interspaces by what lawyers would call circumstantial or indirect evidence. For instance, when we find hydrous minerals occurring in the interior of the mineral constituents of igneous rocks, and when we have independent evidence that these hydrous minerals are of secondary origin, we must admit that water worked its way into the heart of the altered mineral after its birth, unless we are prepared to show that the parent eiystal originally contained enough water to supply the total quantity contained in the parasitical minerals generated in its tissues, as well as all the chemical constituents contained in them. The subject is too large to enter into here. Prof. Blake proceeds as follows :—“ Minute cracks, however, are also present, as is shown by granite and greenstone absorbing water, and containing air, and the capillary action is increased by pressure and heat. [He seems to think, however, that the same conditions would facilitate the introduction of water into the intra-molecular spaces, since] ‘heat signifies an increase in the force of repulsion that keeps apart the atoms [sic] and molecules of which these minerals are composed’ [in which case, heating should make a compound take up more water, but, e.g., ‘the hydrate of sodium sulphate is more and more thoroughly converted into the anhydrous salt as the temperature increases.’ (Fownes.) ] ” 1 Q.J.G.S, 1889, p. 181. Major- Gen. MacMahon—Nature’s Manufacture of Serpentine. 75 From Professor Blake’s insertion of ‘‘[sic]” after atoms, I infer that he regards a molecule as a homogeneous, solid body like a bullet, as it appears to our unaided vision; if so, his conception of the constitution of a molecule can hardly be considered “up to date,” as the following brief extracts from two well-known works will show. “Atoms cannot be divided physically; they are retained side by side, without touching each other, being separated by distances which are great in comparison with their supposed dimensions. A group of two or more atoms forms a molecule.” ! “Nor should it be forgotten that, granting the fundamental hypo- thesis of the molecular and atomic theory, and also granting that each atom can directly interact with a limited number of atoms in a molecule, we are obliged to regard the atoms which form any molecule as performing constant regulated movements, and not as might be supposed by a careless or superficial reader of the atomic explanation of isomerism, as in absolutely fixed positions within the molecule.” ? According to modern conceptions, therefore, the atoms which constitute a molecule are linked together, but the linking is analo- gous to that of moons to a planet, and of a planet and its moons to the sun. The illustration which Prof. Blake adduces, at the end of the above extract, in support of his objection, seems to indicate a fundamental misapprehension on his part. The case of the hydrate of sodium sulphate seems to me to have no bearing on the point at issue. In my paper I discuss the mode in which the hydration of a specified silicate is brought about in a rock below the surface of the earth in the presence of water under considerable pressure; and Prof. Blake opposes the case of the dehydration of a salt by heat under ordinary atmospheric pressure at the surface of the earth, and in the absence of water. There seems to me to be no analogy between the two cases. We all know that at the surface of the earth calcium carbonate can be converted into lime (CaQ) by raising its temperature to a certain point; because at that critical tempera- ture, the force of repulsion, generated by the heat, overcomes the force of the attraction between the calcium oxide and the carbon dioxide, and the latter passes into the gaseous state. Under plutonic con- ditions, on the other hand, the carbon dioxide remains in union with calcium oxide, and crystalline calcite is formed. In my paper I was considering the question of capillary flow under heat and pressure. I showed that, “although the pressure under which water is put in circuluation through the capillary pores depends on the head” (‘‘-43 lbs. per square inch per foot in height”’), “the freedom with which this water flows through the capillaries ” must, with reference to the experiments of Poiseulle, be increased by heat. I contended, therefore, that if ‘the pressure under which water is being injected into the pores of a mineral remained constant, heat would facilitate the capillary flow through those pores 1 Ganot’s Elements of Physics, by Atkinson, p. 1. * Principles of Chemistry, by Patteson Muir, p. 154, footnote. 76 S. 8S. Buckman—Reply to Prof. Blake. by reducing the resistance to the passage of the water.” It is no answer to this contention to say that under totally different con- ditions water is driven off from the hydrate of sodium sulphate by the application of heat. Prof. Blake might as well argue, it seems to me, that marble could not have been formed under plutonic conditions, because, at the surface of the earth, and under the pressure of one atmosphere, the application of sufficient heat will result in the carbon dioxide being driven away from calcium carbonate. It does not require much chemical knowledge to know that if you alter the conditions you may expect to obtain different results. VIII.—A Repty ro Pror, Braxkr’s Comments on Inrerion OOoLITE AMMONITES.? By 8. S. Buckman, F.G.S. ROF. BLAKE’S book is a valuable work of reference; but the criticisms appear to be both hurried and inaccurate. In the notice of my Monograph the title is incorrectly given: there are certain other clerical errors; and some mistakes which a little more investigation would have prevented. While placing his comments in brackets, it is unfortunate that Prof. Blake has not found some means to distinguish between remarks based upon the author’s words, and statements of his own. This is especially noticeable in the “critical digest” of Haugia, where remarks, which appear as if they originated with Prof. Blake, are really my statements in another form. Some of Prof. Blake’s principal comments invite reply. For the sake of brevity I will place them in italics between inverted commas. “The meaning of species and genera... . is of the most restricted kind . . . their distinctions arbitrary.” As to the species, the charge does not seem to be sustained in the part reviewed; for out of twenty-seven species described I am only answerable for five. I have also combined as one species forms which a German author regarded as three; and in other cases I appear not to have made enough species to please my critic. The genera are restricted I own; it is part of the plan of the work. I regard species as various developmental gradations. I look upon genera as groups of species in more or less direct genetic connexion, possessing certain features in common. Since species in direct genetic connexion—and therefore genera—arose one from another by the accumulation of successive slight modifications trans- mitted in accordance with the law of earlier inheritance, the distinctions between species or genera in direct genetic connexion must be arbitrary at certain points. I have always admitted this; but between the homoplastic developments which result from the operation of similar economic laws on the heterogeneous descendants of a remote common ancestor, the distinctions are not really arbitrary, 1 The Annals of British Geology, by J. F. Blake, M.A., F.G.S., p. 308, 1891. S. S. Buckman—Reply to Prof. Blake. 7 though they may appear to be so. It is unfair to adversely criticize genera by comparing, say, the senile metamorphoses of different phylogenetic series. Such degradational forms have lost, to a certain extent, the special features which distinguished the acmic species of their genera. But a system which recognizes the true biological relations of these homoplastic forms by placing them in separate genera is far less arbitrary and far less unnatural than the Waagenian system which Prof. Blake introduced to English readers,! in which homoplastic forms were arbitrarily dragged into the same genus on account of similarity of outward shape, while their true genealogical affinities were completely misunderstood. My efforts towards a natural system of grouping founded on an interpretation of Ammonite genealogy may not be correct at their first start ; but I hope we may never return to so unnatural a grouping as was expressed by Aegoceras, -Arietites, and particularly Amaltheus. ““H. occidentalis has no tubercles, [and therefore should belong to another group|.” Why? No new feature is introduced. There are no tubercles in senile “variabilis,’ or in adult “ jugosa,” and none in “occidentalis” at any stage. It is an illustration of the law of earlier inheritance. Had this loss of a feature been accompanied by the appearance of some new character, I should have been inclined to erect a new genus; but in a simple case of decadence like this I did not see the necessity. A definition by Dr. Haug is given, with which, it is said, my figures do not agree, as they show no fasciculed ribs. I do not know if this be a case of my descriptions “not agreeing with the author's original definition” ; but this is not original—it is a quotation from a letter. I have pointed out (page 154) that my figures do not bear out these remarks ; but in Haug’s original definition and figure of H. occidentalis fasciculed ribs are not noted or shown. “H. Eseri. [The author's figures include several species, none of which agree with the type|.’ What, not figs. 3, and 4, pl. 25 with Quenstedt, Ceph. pl vii. fig. 9 a-b?? Dr. Haug wrote to me, May, 1890, “ Vos H. Eseri de la pl. 25 sont tout-a-fait typiques.” The suture-line “fig. 6, pl. 35,” is not normal, the siphonal lobe being to one side. “G. mactra and D. Moorei” are degraded forms, and not fair samples by which to test the genera. “G. aalense, vars. a—d [no proof given that they are the same species].” I have yet to learn how it can be proved that certain forms are of one species or not. “G., subquadratum identical” with Saemanni, “ differences assigned not borne out by figures.” Similar remarks are made about other species in this “critical digest.’’ I will take this as a sample. The differences given are (in subquadratum) coarser, more reflexed ribs, stronger inner margin, deeper umbilicus more slowly-coiled ” (page 202). I think that these differences are all very noticeable in the 1 Ceph. ; Yorkshire Lias, 1876. -? Allowance must be made for a slight discrepancy in the drawing of the inner margin in Quenstedt’s two figures. 78 Reviews—Proz. Gemmellaro—Crustacea in Fusulina-Limestone. plate—especially the slower-coiling, if any one will measure the figures with compasses. ““G, Saemanni | but apparently including as var. B another solid-keeled species].” This is a most curious criticism in face of the explana- tion of the plate, and the fact that these forms are expressly included in the hollow-carinate section of the Grammocerata. I wrote to Prof. Blake asking him if he had mistaken the carina on the core | (pl. 84, fig. 2) for the true carina. His reply rather astonished me—it showed that he did not understand the structure of a hollow- carina. He “thought it was the presence of a keel in the shell, but not on the cast,” which made a hollow carina. This is certainly not the case: it is the presence of a partition-band over- lying the abdominal part of the cast containing the siphuncle. The partition-band connects the inner walls of the overlying elevated carina, and so there is formed a hollow triangular tube around the periphery of the Ammonite. The abdominal part of the core may be carinate or rounded—this does not affect the structure of the hollow-carina in the least. I fully explained the structure of the hollow-carina in my Monograph, page 81, footnote, and illustrated its various phases in pl. A. In fig. 47 of that plate I figured a carinate core bearing a hollow-carina, and this feature is to be very frequently noted in the genera Witchellia, and Sonninia, as well as in Grammoceras. A desire not to occupy too much space alone prevents me from replying to all Prof. Blake’s criticisms ; but from the above remarks I leave it to be judged whether the critic in an attempt to correct the author has not himself fallen into errors. REVIEWS. —_»—— I.—ConTRIBUTIONS TO THE PALMONTOLOGY oF SICILY. Tae CRUSTACEA OF THE FUSULINA-LIMESTONE OF THE VALLEY OF THE Sosto Rrver In THE Province oF Pauermo, Sriciry. By Prof. G. G. GEMMELLARO. I Grosracer Det CaLcart con FusuLINA, DELLA VALLE DEL FiumMsE Sosio, NELLA Provincia pI PatErMmo 1n Srcru1a. Memoria di Gaetano Giorgio Gemmellaro, Professore di Geologia della R. Universita di Palermo. Memorie delle Societi Italiana delle Scienze fisiche e matematiche, Tomo viii. ser. 8, No. 1, pp. 40, and 5 plates. 4to. Naples, 1890. HE author refers this Fusulina-limestone to the “ Permo-Carboni- ferous” formation, and finds in it the following fossils.— J. Trinopites: Proetus, Steininger, 2 new species; Phillipsia, Portlock, 4 new species, and of the ‘‘subgenera” Griffithides, Portlock, and Pseudophillipsia, nov., one new species each. If Prof. Gemmellaro is correct in his determination of these beds, then these Trilobites are younger than any hitherto discovered, and later than the true Carboniferous in age. Reviews— Newton’s British Pliocene Vertebrata. 79 II. Macrvurovs Crustacean. Paleopemphix, gen. nov., with three new species. These carapaces doubtless belong to some small Macrurous Decapod, but it is not easy to recognize their ancestral relationship to Pemphix of the German Muschelkalk. The rostral portion of the carapace is curiously stunted (as in the Crangonide), and the antennal (antero-lateral) angles very prominent. These Sicilian forms are all seen in profile, but most of the early Carboni- ferous genera had the carapace flattened out, dorsally, as in the Eryonide of the Liassic and Oolitic period, and in the recent Polycheles. IiJ. Bracuyurous Crustacnans. Paraprosopon, gen. nov., with one new species. This seems to belong to the genus Cyclus of De Koninck, and closely resembles O. Jonesianus, H. Woodward, in particular (see Grou. Mac. 1870, Vol. VII. Pl. XXIII. p. 558, Woodcut, Figs. 1-2). IV. Oonocarcinus, gen. nov., with 3 new species. This form, according to the author, has its nearest ally in Hemitrochiscus para- doxus, Schauroth. It has, however, very much of the form of Caryon, Barrande, and reminds one of the head in Spherexochus. But most of all Oonocarcinus resembles the coalesced segments of the buckler-like abdomen of the female in the Leucosiade (cf. Bell, Mon. Leucosiada, Trans. Linn. Soc. 1855, vol. xxi. p. 277, pls. xxx.—xxxil.). Perhaps it may represent a part of an early Brachyurous Decapod; if so, it has an additional interest for us. V. Ostracopa. Cypridinella, Jones & Kirkby, 2 new species ; Cypridellina, J. & K., one new species ; Cypridella, De Koninck, 2 new species ; Cypridina, Milne Edwards, 2 new species; Philomedes, Lilljeborg, 1 new species ; Eniomoconchus, M‘Coy, 1 new species ; Entomis, Jones, 2 new species; Beyrichia, M‘Coy, 1 new species. These have an exceedingly close resemblance to the true Carbon- iferous species of Britain and Belgium, and at first sight might in most instances be taken for them. ‘The figured “ Beyrichia,” how- ever, is a very doubtful specimen. In bringing together the members of this most interesting local fauna, and illustrating it in so clear and admirable a manner, the author has done good service to Paleontology, and deserves our best thanks. H.W. & T. RB. J. II].— British Puiocenr VERTEBRATA. “THe VERTEBRATA OF THE PxLiocENE Deposits oF Britain.” By HE. T. Newton, F.G.S., F.Z.S. Mem. Geol. Surv. United Kingdom, 1891, pp. i-xii, 1-137, Pl. I—X. HROUGH the generosity of the author we have been favoured with a copy of this valuable Memoir, which forms a companion volume to Mr. Newton’s well-known work on “The Vertebrata of the Forest Bed Series of Norfolk and Suffolk,” published by the Geological Survey in 1882. The Memoir also seems to have been prepared in connexion with another Survey publication by Mr. Clement Reid, “The Pliocene Deposits of Britain,” said to have 80 Reriews—Neuwton’s British Pliocene Vertebrata. been issued in 1890, but of which we have not yet been privileged to receive a copy for review. The Forest Bed Series of Norfolk and Suffolk being included by the Geological Survey among Pliocene Deposits, the new volume contains many observations supplementary to Mr. Newton’s former work on the Forest Bed Vertebrata; and one double plate is devoted to the antlers of Cervide, of which no illustrations were previously given. The principal interest of the Memoir, however, centres upon the vertebrate fossils of the English Crags, which are carefully subdivided into horizons in accordance with Mr. Reid’s classification, « By far the larger part of the Vertebrate remains which are said to be from the Red Crag really come from the Nodule-bed (Bone-bed of some authors) which occurs at its base; and, further, a Nodule- bed with similar fossils is known to occur also under the Coralline Crag. Many of the fossils from the Nodule-bed have been un- doubtedly derived from the denudation of Eocene strata, while others seem to be the remanié of Pliocene beds older than the Coralline Crag, but of which no traces are known to occur in Britain. It has been suggested that most of the Nodule-bed Vertebrates have been derived from Miocene strata, but there seems little evidence to support such an idea. Many Vertebrate remains have been found actually in the Coralline Crag and Red Crag above the Nodule-bed. The same is the case with the Norwich Crag, many specimens being obtained above the Basement Bed, or Mammaliferous Stone-bed.” Many new specimens are noticed and well illustrated in the course of the work, but the majority of Mr. Newton’s observations have already appeared elsewhere, and they are now presented merely in a collected form, with references to the original places of publication. These references, indeed, with those also to other authors, form the only blemish in the work demanding serious adverse criticism. They are all placed within round brackets in the text itself, and render many pages quite unreadable, except by the closest study. The nominative is frequently separated from the rest of a phrase by one and a half or two lines. Perhaps, however, the saving of the extra cost of printing footnotes results in some advantage, for the Memoir is issued to the public at the unusually reasonable price of four shillings. It would be impossible in the course of a brief review to do justice to the most interesting and valuable mass of information concerning the Pliocene Vertebrata now brought together. It must thus suffice to remark upon a few striking points. Mr. Newton considers that Mr. Lydekker is most probably correct in referring the teeth of Hyena from the Red Crag Nodule-bed to the existing H. striata ; and a right lower canine from Felixstow is now provisionally added to the evidence of the species. Owen’s determination of the common Wolf from the Red Crag Nodule-bed is also confirmed, while an upper premolar and two canines are additional specimens recorded. Canis primigenius, Mr. Newton thinks, may be founded on a Cetacean tooth. The occurrence of Cervulus dicranoceros, first determined by Sir Richard Owen and since questioned by Dawkins and Lydekker, Reviews—Newton’s British Pliocene Vertebrata. 81 is now admitted from new evidence; and the discovery of Cervus elaphus and Cervus etueriarum in the Forest Bed is definitely con- firmed. Mr. Newton well remarks that ‘“‘of two uncertain names it seems best to keep the one which has been so long in use, rather than introduce another equally uncertain;” and he thus describes the larger teeth of pigs from the Red Crag as Sus antiquus? Kaup. Hipparion is known only from the Red Crag Nodule-bed ; and while agreeing with Mr. Lydekker that most of the teeth of Rhinoceros from this horizon may best be assigned to R. incisivus, the author considers that some may still belong to R. Schleiermacheri. Elephas meridionalis is definitely known from the Red Crag Nodule-bed, but Hlephas antiquus has not been obtained below the Norwich Crag. There is still no evidence of Mastodon in the Forest Bed Series. To be “fashionable” Mr. Newton adopts the name Microtus, which literary ‘‘research”’ has lately shown to be applicable to the Voles; but “ Arvicola”’ is placed in brackets to explain what is meant. The Cetacean remains from the Crag are treated in accordance with Mr. Lydekker’s determinations; and the so-called tooth of Ursus arvernensis described by Lankester is ascribed to Squalodon. A vertebra and tooth of Orca gladiator from the Forest Bed are new, and another vertebra from the same horizon is referred to Pseudorca. The fish-remains are very fragmentary, but numerous, and the de- scription of several distinct otoliths of Gadus is interesting. One tooth from the Coralline Crag is ascribed to the Wolf-fish (Anarrhichas lupus) ; and the occurrence of Thynnus scaldiensis, also in the Coralline Crag, is confirmed. A tabulated list of species and a general summary conclude the Memoir. Notwithstanding the fragmentary character of all the remains, Mr. Newton’s most painstaking researches have invested this summary with great interest and value. “It seems from a con- sideration of the Pliocene Vertebrata that the climate of England in the earlier part of that period was decidedly warmer than it is at the present day, and approached sub-tropical conditions ; and that, notwithstanding minor variations which may have subsequently taken place, the general tendency was to become colder, so that in the Forest-bed times the climate was temperate, with, possibly, periods of greater heat and still greater cold, perhaps partly due to continental conditions, which at length culminated in the Glacial or Pleistocene Epoch. ‘The earliest Pleistocene deposit recognized being the ‘Arctic Freshwater Bed’ of Norfolk, which is characterized by an assemblage of Arctic plants, and a Spermophilus, and occurs immediately below the Boulder Clay.” Tue Geoxocicat Socirry.—The Medals and Funds to be given at the Anniversary Meeting of the Geological Society on February 19 have been awarded as follows:—The Wollaston Medal to Baron Ferdinand von Richthofen ; the Murchison Medal to Professor A. H. Green, F.R.S.; and the Lyell Medal to Mr. George H. Moreton. The balance of the proceeds of the Wollaston Fund to Mr. O. A. Derby; that of the Murchison Fund to Mr. Beeby Thompson ; that of the Lyell Fund to Mr. E. A. Walford and Mr. J. W. Gregory, and a portion of the Barlow-Jameson Fund to Prof. C. Mayer-Eymar, DECADE Ill.—VOL. IX.—NO. II. 6 82 = Reriews—J. H. L. Vogt’s Formation of Iron Ores. IIJ.—On tue Formation OF THE Principat Groups OF JRON-ORE Deposits Occurrine In Norway anp Swepen. By J. H. L. Voer. Transactions of the Geological Society in Stockholm, No. 188, Vol. 18, Part 5, May, 1891, pp. 476-536, PI. 8. Om DaNNELSEN AF DE VIGTIGSTE IN NORGE 0G SVERIGE REPRESEN- TEREDE GRUPPER AF JERNMALMFOREKOMSTER AF J. H. L. Voer. Geologiska Féreningens i Stockholm Foérhandlingar, Band XIII. Maj, 1891, s. 476. HE author of this valuable communication has, in his work on slags, paid special attention to the conditions under which the silicates and other minerals are developed in magmas of varying composition. He is now extending the principles established by this kind of work to the igneous rocks of volcanic and plutonic origin. In the paper under review he deals especially with the origin of iron-ores of the Ekersund-Taberg type. ‘These he attributes to ‘magmatic concentration ” in strongly basic eruptive rocks; and in discussing the question of concentration he necessarily deals with matters or general interest to all students of igneous phenomena. Many of the facts referred to by the author have been described by previous observers, but they have never been grouped together so as to illustrate a general theory. Under these circumstances a somewhat extended notice of his paper appears to be thoroughly justifiable. The author commences by remarking that ore-deposits may be divided into very well marked groups by taking into consideration the genetic principle which has been shown to be of so much value for classificatory purposes in other departments of natural science; and, after a general review of the principal Norwegian occurrences suggests the following classification :— I. Ores formed by magmatic concentration in strongly basic igneous rocks. II. Ores formed by pneumatolytic processes [i.e. a kind of subterranean fumarole- action; ¢.g. tin-stone deposits of Cornwall].! III. Ores formed by sedimentation. IV. Ores formed by metasomatic processes [¢.g. Cleveland ironstone]. VY. Ores formed by deposition of ferrous carbonate and other minerals in cracks. In the consolidation of igneous magmas the ores and accessory minerals—magnetite, ilmenite, hematite, pyrite, magnetic pyrites, apatite, zircon, spinelle, titanite, perowskite, etc.—are first formed. Then follow the ferro-magnesian silicates—olivine, mica, pyroxene, amphibole—and lastly the minerals of the felspar group and free quartz. There may be a certain amount of overlapping in the minerals of the last two groups; but in a general way the order is that indicated above. Now the ore-deposits with which the author is immediately concerned can be accounted for by supposing that the chemical compounds of which they are composed became concentrated by diffusion-processes which are imperfectly under- stood at present. According to this view they would be analogous to the “ basic patches” common in many eruptive rocks. 1 The remarks in square brackets are interpolated by the reviewer. In what follows the author deals exclusively with the ores belonging to the first group. Reviews—J. H. L. Vogt’s Formation of Iron Ores. 83 As illustrating, in a general way, the effects of such diffusion, a dyke, 10 metres wide, occurring near Huk, in the Christiania district, is described. The centre of the dyke is a mica-syenite- porphyry, consisting of large crystals of orthoclase lying in a light red, fine-grained ground-mass. About one or two metres from the junction the ground-mass takes on a grey colour due to increase in the magnetite. As the junction is approached, the felspars decrease ‘in size, plagioclase takes the place of orthoclase, and the ground- mass becomes darker and more compact. The actual margin is formed of a black rock, rich in iron, and containing a few por- phyritic crystals of felspar (plagioclase) and mica. Pyrite increases as the junction is approached. The microscope shows that magnetite and biotite are very abundant in the marginal rock, which may be described as a kersantite. Chemical analysis establishes the fact that phosphoric acid is also more abundant at the margin than in the centre. ‘The amount found corresponds to ‘51 per cent. of apatite in the centre and 1:44 per cent. at the margin. There is nothing in the appearance of. the dyke to suggest that there have been two intrusions. The transition from one type of rock to the other is gradual, and can only be accounted for by supposing that the magma became differentiated, before consolidation, by a concentration at the margin of the chemical compounds of the first formed constituents. This case is so interesting that we quote below (1) the composition of the original magma as reckoned from actual analyses; (2) the composition of the centre; and (3) the composition of the margin: SiO2 eet 62 Ric 63 oo 47 Al,03 S06 17°5 BRD WW ab 20 Fe,03 i 75 FeO } 2 28 5 MgO 3 2°75 5:5 CaO 3°5 3 7:5 Na,O 5 5:5 4 K,0 4 4-5 1 FeSe 1 1 3 Having illustrated in this way the general. principles of magmatic concentration, the author describes in detail the ilmenite-deposits of the Ekersund-Soggendal district. They are found in a region composed of plutonic rocks which may be grouped under the following terms :—labradorite-rock (a norite extremely poor in ores and ferro-magnesian constituents), hypersthene-norite, biotite-norite and enstatite-granite. Dykes (exclusive of the ore-deposits) traverse the district. They may be classified, in the order of their formation, as follows :— I. Ilmenite-hypersthene-labradorite dykes of pegmatitic character. II. Norite dykes. III. Diabase dykes, generally containing olivine. Titanite is absent from the labradorite-rock and the true norites, but is found in the enstatite-granite. All the above rocks evidently belong to the same general period. They are the products of the consolidation of one magma-basin. The ilmenite-deposit of Storgangen may be regarded as forming a dyke 8 kilometres long, and 20 to 70 metres wide. It consists of 84 Reviews—J. H. L. Vogts Formation of Iron Ores. ilmenite, hypersthene and labradorite; and is, in fact, an ilmenite- norite. The average of ilmenite in the whole dyke is estimated at 40 per cent. In places as much as 70 or 80 per cent. may be found. The dyke is separated from the labradorite-rock by sharp boundaries. The same type of rock is found in several other portions of the norite-district ; sometimes with lower and sometimes with higher percentages of ilmenite. As a rule it occurs under the same con- ditions as at Storgangen, and rarely passes over by gradual stages into labradorite-rock. In the true ore-deposits (Blifjeld) the ilmenite predominates to such an extent that the rock loses its norite character altogether, and consists of 90 per cent. or even 95 per cent. of iron- ore. It occurs as dykes from two to six metres thick, and from one to two hundred metres long. Sharp fragments of the labradorite- rock occur as inclusions in the mass of the ore, thus proving con- clusively that the veins are of later date than the surrounding rocks. Transitions may be observed between the ore-deposits and the pegmatitic dykes above referred to. The author gives several analyses of the ore, one of which we quote. Orr FROM KyLanp. si0, Rar ose tee ae 44°05 Fe,03 ae |... a FeO ae wee Bae oe 34°17 MgO oe | ee 3-04 Totalyees ae 99°97 A certain amount of magnesia is always found. This accords with the view that the formation of a magma, extremely rich in magnesia, is an intermediate stage in the formation of iron-ores by the process of concentration. The dykes of olivine-diabase and norite cut the ore-deposits. Apatite is lowest in the labradorite-rock, somewhat more abundant in the ilmenite-norite (‘05 per cent.), and reaches its maximum (5 per cent.) in the dykes of norite and olivine-diabase. The ore-deposits of Taberg, in Smaland (Sweden), described by Sjogren and Tornebohm, consist of titano-magnetite with olivine, traces of biotite, and a strongly basic felspar. The last-mentioned constituents are entirely absent from the richest ores. The mode of occurrence is different from that of Ekersund. The ore in this case is found in the centre of a mass of olivine-hyperite into which it passes by insensible gradations. The area occupied by the olivine-hyperite and the magnetite-olivinite (ore-deposit) is elliptical in form, and measures about one mile, by rather less than one-third of a mile. Similar rocks occur in other localities in Sweden and Dr. Wadsworth has shown that the ore of Rhode Island is of the same character. That ore-deposits of the above type are the result of concentration in plutonic magmas is indicated by the following facts :— (1) The different ores stand petrographically related to the surrounding rocks (e.g. magnetite-olivinite to olivine-hyperite and ilmenite-norite to labradorite rock), (2) ‘The ore in many cases passes gradually into the surrounding rock. (3) In no case is there any evidence of the introduction of material by solutions or pneumatolytic processes. The segregations are characterized by the minerals of the surrounding rocks, and by these alone. Reviews—J. H. L. Vogt’s Formation of Lron Ores. 85 The author next proceeds to consider the main facts relating to concentration without reference to the causes which may have pro- duced it, or to the chemical and physical conditions under which it has taken place. The iron oxides (ilmenite and titano-magnetite), which are the first minerals to form, are those which are most strongly concentrated. The ferro-magnesian compounds have also been concentrated, but not to the same extent. The original magma of the labradorite rock of the Ekersund dis- trict may be supposed to have consisted of 2 parts ilmenite, 4 parts hypersthene and 94 parts labradorite; at a later stage of 6 Il. + 8 Hyp. + 86 La. ; later still of 18 Il. + 16 Hyp. + 66 La.; again later of 40 Il. + 85 Hyp. + 25 La.; and lastly of from 80 to 95 or even 99 °/, of ilmenite, the remainder being hypersthene and labradorite. Similar phenomena are illustrated at Taberg and in the dyke at Huk. Titanic acid is concentrated along with the iron oxides and enters into composition with them in the case of the segregations in basic eruptives. It is interesting to notice that-in the Ekersund deposits the ore is ilmenite (RTiO,nF'e,O, whence R= Mg, Fe, Mn), which may be regarded as formed in part of a metatitanate; in the more strongly basic rocks of Taberg it is titano-magnetite (Fe, TiO, nFe,0,), which contains an ortho-titanate. In the former case the associated ferro-magnesian silicate is hypersthene, a metasilicate, and in the latter case it is olivine, an orthosilicate. In more acid magmias the titanic acid determines the formation of sphene, and the iron-ores if present are comparatively free from this constituent. In facts of this kind we see the influence of mass in modifying the chemical affinities. Chrome-oxide, if present, is concentrated along with the basic minerals. The ilmenite of Ekersund contains chromium, and a little chrome-spinelle is found in the ilmenite-norite. Manganese is con- centrated, but not to the same extent as iron. Phosphoric acid may be concentrated; but not according to the same laws as iron, for it is more abundant in the dykes of diabase and norite than in the ore-deposits. The position in the eruptive mass in which the rocks formed by concentration-processes are to be found is not the same in all cases. In the case of the dyke at Huk the basic parts form the margins ; in the Taberg district the ore occupies a central position in the area formed of eruptive rocks; in the Ekersund occurrences it forms dyke-like masses which are sharply separated from the country rock. The concluding part of the paper is occupied by a discussion of the processes by which concentration may have been brought about. Three ways are possible:—1l. The minerals may be formed and mechanically collected in certain parts of the mother liquor. 2. The minerals may be formed and again dissolved in some other locality, thus producing a basic magma. 3. Concentration may take place by molecular diffusion without the actual separation of minerals. The author considers that the first two methods have not been concerned in the production of the concentration which has given 86 Reviews—J. H. L. Vogt’s Formation of Iron Ores. rise to the Ekersund deposits, for microscopic examination shows that the minerals have been developed in sitt#i—not mechanically collected—and there are no corroded grains such as might be expected if the second cause had operated. We are therefore limited to the third method. The homogeneity of a solution may be destroyed by temperature- differences and by gravity. The influence of the former has been experimentally established by Soret, and follows as a necessary consequence of Van ’t Hoff’s theorem that osmotic pressure in the case of dilute solutions obeys the laws of gaseous pressure. The influence of the latter has been deduced experimentally by Gouy and Chapéron from the laws of thermo-dynamics. Where solutions become heavier by concentration, the lower part will be more concentrated than the upper part. The difference is slight, and can only be recognized with difficulty when a tube 100 metres high is. used. The specific gravity of a molten magma will increase with an increase in the number of molecules of magnetite, ilmenite, magnesia- iron-silicates, pyrite, ete. Hence these molecules will, according to the law of Gouy and Chapéron, be more abundant in the lower than in the upper portion of a magma-basin. Differences of temperature operating according to what the reviewer has elsewhere termed Soret’s principle will cause the same molecules to accumulate in the colder portions of the same magma-basin. Another cause which is believed by the author to be effective in aiding concentration is magnetic attraction. The different iron- compounds when dissolved in silicate-magmas are, doubtless, para- magnetic. Under the influence of the earth’s magnetism the molecules may become orientated; but, so long as they are uniformly distributed throughout the mass, there can be no con- centration due to magnetic attraction. If, however, owing to tem- perature-differences, or to gravity, a local accumulation of magnetic molecules takes place, the magnetic attraction may cause the con- centration to become more and more pronounced. The dyke at Huk furnishes an excellent illustration of concen- tration due to differences of temperature. The magma of the ore- deposits of Ekersund and Taberg must, however, have been formed by concentration in the deeper portions of a magma-basin. A certain influence may be ascribed to gravity acting on the specifically heavier molecules; but it seems hardly probable that the important results which have been observed can be due to this action alone. Magnetic attraction operating constantly and for long periods may, however, when taken in connection with gravity, have given rise to the necessary amount of concentration. The high specific gravity of the earth may be due to the con- centration of the heavier molecules in the central parts, by the causes above referred to, during the earlier stages of the history of the planet. If so, the ore-deposits under consideration are the genetic equivalents of the originally molten kernel of the globe. The intimate relation between the ore-deposits and meteorites has been especially commented upon by Wadsworth. J. dewey Reports and Proceedings—Geological Society of London. 87 REPORTS AND PROCHEHDINGS. ——+>>—_—__ GrotocicaL Society or Lonpon. T.—Dec. 23, 1891.—W. H. Hudleston, Esq., M.A., F.R.S., Vice- President, in the Chair.—The following communications were read : 1. “On Part of the Pelvis of Polacanthus.” By R. Lydekker, Esq., B.A., F.G.8. The specimen described in this paper was acquired by the British Museum from the collection of the late Mr. Beckles, and is from the Wealden, probably of the Isle of Wight. It is the central part of a Dinosaurian ilium, with portions of sacral ribs attached. The point of special interest is a flat plate of bone, evidently a portion of dermal armour, resting on the upper border of the ilium ; and this suggests comparison of the specimen with the dorsal shield of Polacanthus Foxit. Such a comparison shows that the present specimen belonged to a Dinosaur closely allied to, if not identical with, P. Foxit. 2. “On the Gravels on the South of the Thames from Guildford to Newbury.” By Horace W. Monckton, Esq., F.G.S. The author stated that the greater part of the hill-gravel in the district referred to belonged to the Southern Drift of Prof. Prestwich, and that the valley-gravels for the most part consisted of material derived from the Southern Drift. Small patches of Westleton Shingle and Glacial Gravel occurred near Reading and Twyford. He divided the Southern Drift into three classes :— 1. Upper Hale type, characterized by the abundance of small quartz pebbles and the scarcity of chert. 2. Chobham Ridges type, with abundance both of small quartz pebbles and chert. 3. Silchester type; quartz scarce, and chert very rare or altogether absent. He described the localities at which these types occurred and their limits of distribution, and then referred to the Glacial Gravels of the Tilehurst plateau, which he believed to have been deposited before the excavation of the valley of the Thames between Reading and Goring. The author then dealt with the valley-gravels, which he believed to be mainly derived from the hill-gravels of the immediate neigh- bourhood, and showed how the various types of hill-gravel had contributed materials for the valley-gravels. He explained that, with the possible exception of the Westleton Shingle, he entirely rejected the theory of marine action in connexion with the formation of these gravels, and thought that the Glacial Gravels were probably for the most part due to floods during melting of large quantities of ice. The remaining gravels, he believed, had been “spread out by water in valleys; as denudation proceeded, the gravel, by protecting the ground upon which it lay, came to stand out as the capping of the plateaux and hills; as the gravel itself was denuded, the materials were carried to lower levels, forming new gravels; and 88 Reports and Proceedings— this process has been repeated up to the present time. He explained that Prof. Rupert Jones and Dr. Irving had already adopted this theory in part, but that he differed from them in the entire exclusion of marine action. 3. “The Bagshot Beds of Bagshot Heath.” By Horace W. Monckton, Esq., F.G.S. The author stated that certain changes in the classification of the Bagshot Beds had recently been proposed, and he gave reasons for preferring that at present in use, which was originally proposed by Prof. Prestwich in 1847, viz. a threefold division into Upper, Middle, and Lower Bagshot. He then argued against the theory that the Upper and Middle Bagshot Beds overlap the Lower Bagshot on the north-western side of the Bagshot district, as had been suggested by Dr. A. Irving ; and, dealing with the various localities where Upper Bagshot had been alleged to exist resting on Lower Bagshot or on London Clay, he contended that in every case the evidence in favour of Upper Bagshot age broke down on examination. IL.—Jan. 6, 1892.—W. H. Hudleston, Esq., M.A., F.R.S., Vice- President, in the Chair.—The following communications were read : 1. “On a new Form of Agelacrinites (Lepidodiscus Milleri, n. sp.) from the Lower Carboniferous Limestone of Cumberland.” By G. Sharman, Esq., and E. T. Newton, Esq., F.G.S. Among a large series of fossils obtained during the Geological Survey of Cumberland and Northumberland, there are two which are referable to that remarkable and rare group of Hchinoderms, the Agelacrinitide. The more perfect of these specimens is from the Lower Carboniferous rocks near Waterhead, on the River Irthing, and forms the subject of this communication. The disc- like fossil is only about four-tenths of an inch in diameter, and scarcely rises above the shell to which it is attached ; nevertheless, it is so well preserved as to allow much of its structure to be studied. It is referred to the genus Lepidodiscus, and is seemingly closely related to L. Lebouri, described by Mr. Percy Sladen before this Society in 1879; but it also has affinities with DL. cinciunatiensis and L. squamosus. From all these, however, the present specimen differs in having the pyramid in the middle of the interradial space, in possessing shorter arms, and in being much smaller. This fossil is to be named Lepidodiscus Milleri, after Mr. Hugh Miller, under whose direction these fossils were collected by Mr. J. Rhodes. 2. “The Geology of Barbados.—Part II. The Oceanic Deposits.” By A. J. Jukes-Browne, Esq., B.A., F.G.S., and Prof. J. B. Harrison, M.A., F.G.S. The Oceanic deposits rest unconformably on the Scotland Series, with which they contrast strongly in every respect. They are divisible into five portions :— 1, Gray and buff calcareous marls (Foraminiferal). 2. Fine-grained red and yellow argillaceous earths. 3. Pulverulent chalky earths (Foraminiferal). Geological Society of London. 89 4, Siliceous earths (Radiolarian). 5. Calcareo-siliceous and chalky earths (Foraminiferal). The whole series is more calcareous in the northern than in the southern part of the island, and layers of volcanic dust occur in it at various horizons. There is everywhere a passage from the more siliceous to the more calcareous earths. From the paleontological and lithological evidence the authors conclude that the depth of water in which the Oceanic beds were deposited varied between 1000 and 2500 fathoms. The micro- scopical and chemical evidence shows that the Radiolarian earths are similar to modern Radiolarian ooze; that the calcareo-siliceous earths are similar to what is called by Prof. Haeckel “mixed Radiolarian ooze”’; that some of the Foraminiferal earths are comparable to Globigerina-ooze from 1000 fathoms, and that others greatly resemble European Chalk; and, finally, that the coloured clays bear a strong resemblance to the so-called “red clays” of modern oceanic areas. Hence the raised Oceanic deposits of Barbados seem to present us with an epitome of the various kinds of deposits which are found on floors of warm seas at the present day. Equivalent deposits are known in Trinidad and Jamaica; and it is inferred by the authors that the whole Central American and Caribbean region was deeply submerged during the Pliocene period, leaving free com- munication at that time between the Atlantic and Pacific Oceans. An Appendix by Mr. W. Hill treats of the minute structure of the Oceanic earths and limestones and of the Foraminiferal muds and detritial earths; and this is supplemented by a Report from Miss Raisin on the inorganic material of certain Barbados rocks. 3. ‘ Archeopneustes abruptus, anew Genus and Species of Hchinoid from the Oceanic Series in Barbados.” By J. W. Gregory, Esq., B.Sc., F.G.S.: This genus belongs to a group of Echinoidea which has given some trouble to systematists, owing to the union of the characters of the orders Cassiduloidea and Spatangoidea; the other genera belonging to the group are Asterostoma, Pseudasterostoma, and Palgopneustes. The evidence of the new Echinoid throws light upon the affinities of these genera. The main points suggested by a study of the new species are :—(1) the abandonment of the name Pseudasterostoma as a synonym of Palgopneustes ; and (2) the inclu- sion of the true Asterostoma, Palzopneustes, and Archeopneustes in the Adete Spatangoidea, whereby the Plesiospatangide are left as a more homogeneous family, though bereft of the chief interest assigned to it. A tabular summary of the nomenclature of the group is given. The best-known fossil species of Asterostoma and Paleopneustes occur in Cuba, in deposits referred to the Cretaceous owing to the resemblance of these Echinoids to the common Chalk Hchinocorys scutatus. The new genus includes a species from the same deposit, which is probably of the same age as the Bissex Hill rock from which the new species was obtained ; this is at the top of the Oceanic Series, and belongs to the close of the great subsidence. 90 Correspondence—Prof. T. G. Bonney. CORRESPONDEHNC#. CRYSTALLINE SCHISTS OF THE LEPONTINE ALPS. Str,—Permit me to express my sincere regret to Dr. Stapff for having abbreviated not only his name but also—what is worse—his life. How the second misconception arose I cannot tell, but it is certainly not a recent one. Perhaps I ought also to apologize for not referring to his papers more frequently, but the truth is that I have only seen one of them, and that (for reasons on which it is need- less to enter) I had but little opportunity of consulting. For this neglect some of my fellow-workers will probably visit me with censure. Be it sv, I can only say that I do not always find myself quoted “over the water,” and in this matter take as my maxim: hance veniam petimusque damusque vicissim. Except for this, my only purpose in writing, is to excuse myself from discussing at present Dr. Stapff’s friendly and interesting com- munication. I am still at work on the subject of that singular complex of rocks in and about the Urserenthal, and cannot publish anything more till I have tested certain hypotheses on the ground. This I fear cannot be done during the present summer, since I an- ticipate that my steps must be turned in another direction, and I am not one of those fortunate persons who can undertake a long journey at pleasure in order to investigate a geological problem. So I ask permission only to observe :— (1). That I do not deny the possibility of Jurassic rocks or Carboniferous rocks entering into the complex of the Urserenthal. But I doubt the occurrence of organisms in the Altkirche marble. Without seeing the slides, it would be difficult to express an opinion on the nature of the objects figured by Dr. Stapff on page 18 of this volume; the upper one certainly has an organic aspect; the lower strikes me as more doubtful. But the nature of the objects is not the only thing to be considered. (2.) That, if Iam right in understanding Dr. Stapff to assign the Piora schists to the Carboniferous system, this identification appears to me only an hypothesis. If there be any valid evidence in favour of it, this is unknown to me, while I am aware of some serious difficulties in which we should be landed by accepting it. (3.) That, from what I know of crystalline rocks and their ways, I venture to doubt the accuracy of the identification (p. 17) of “rolled quartz grains (sand) in some beds of the Guspis micaceous gneiss.” For years I hunted for traces of an original clastic structure in gneisses and certain associated crystalline schists, longing to find them, but in vain. Again and again I have seen them curiously simulated here and there, by the results of pressure, and so, having been often taken in for a while, I have become rather sceptical. T. G. Bonney. CONCHOLOGICAL NOMENCLATURE. Sirn,—Mr. A. J. Jukes-Browne, in the January Number of the GroLocicaL MaGazine, takes objection to some points in Concho- logical Nomenclature adopted in the “Systematic List of the F. E. Correspondence—Ur. R. B. Newton—Mr. T. M. Reade. 91 Edwards Collection of British Oligocene and Eocene Mollusca,” to which I beg to offer the following remarks. Mr. Jukes-Browne calls attention to the proposed disuse of Cytherea and Triton; two generic names which the reviewer discussed when noticing my book in “Nature” of October 29th, 1891. In a sub- sequent issue of the same Journal (November 12th, 1891), Baron Osten Sacken advocated the retention of Cytherea because the earlier Dipteroid genus of the same name being a synonym, and therefore rendered obsolete, could, from his point of view, be retained for another group. Evidently these writers have not consulted the literature dealing with the Molluscan genera under discussion, or they would have ascertained that Lamarck’s Cytherea had been replaced by his earlier Meretriz by many competent authorities such as Dr. J. H. Gray in 1847 (Proc. Zool. Soc. p. 183), Deshayes in 18583 (Cat. Conchifera British Museum, p. 34), H. and A. Adams in 1857 (Genera, p. 423), and other specialists, including Dr. Paul Fischer, who, in the latest and most elaborate treatise (Manuel, 1887, p. 1079) on the Mollusca, fully adopts it. Concerning the name of Triton, we find that it has been used for three separate organisms: by Linneeus for a Cirripede in 1767; for an Amphibian by Laurenti in 1768; and for a Mollusk by De Montfort in 1810. Writers on the Reptilia have ceased to regard it as one of their genera, because the Linnean name has priority, and they have sub- stituted Molge for it, a genus founded by Merrem in 1820. On the same grounds Malacologists also refuse to acknowledge it (as exemplified by the works of H. and A. Adams, Philippi, Weinkanff, Stoliczka, Zittel, Dall, ete.). Link’s Tritonium of 1807 being the name now generally known for this shell, but as this differs from Miiller’s Tritonium of 1776, I have utilized the next most appropriate synonym, and brought into prominence Schumacher’s Lampusia of 1817. I hope this explanation will serve to show Mr. Jukes-Browne and others interested in this subject that the rejection of Cytherea and Triton as generic names in Zoology, being brought about through the operation of the law of priority, is now almost universally acknowledged. R. Butten Newron. Britise Museum (Naturat History), CRomweELt Roap, January 13th, 1892. READE’S THEORY OF MOUNTAIN BUILDING. Srr,—I read Mr. Jukes-Browne’s criticisms of some points in my “Origin of Mountain Ranges’! with interest, and until ] came to the Postscript, which, like a lady’s letter, contains the most important part of the communication, contemplated replying to them. This last paragraph however being destructive of the need of the pre- ceding criticisms puts another complexion on the matter. Mr. Jukes-Browne must be aware that I have replied to Mr. Davison’s arguments against the “expansion theory of Mountain 1 Grou. Maa. Jan. 1892, p. 24. 92 Obituary—Prof. C. Ferdinand von Roemer. evolution,’ ! and it appears unreasonable to expect me to discuss a fundamental principle at second hand, especially with the inadequate materials contained in the Postscript. Until Mr. Jukes-Browne has brought this central idea of Mr. Davison’s, which he adopts, into harmony with his own ideas, it would be a waste of my time to traverse his criticisms, some of which present themselves to my mind as exceedingly immature. When this is done I shall be prepared to consider his arguments, and I must also ask him to be good enough to restate the first paragraph on page 28, as after re-reading I fail to understand it. His quantitative illustration is unfortunate as he has only exacted a tithe of what he is entitled to in my figures :— 500 x 500 x 20 is not five hundred thousand, but five millions. Park Corner, BLUNDELLSANDS, T. Mextiarp READE. Jan, 8, 1892. O75 EeaeASrS Y - a HERR GEHEIMER BERGRATH PROFESSOR DR. C. FERDINAND VON ROEMER, FOREIGN MEMBER, GEOLOCICAL SOCIETY, LONDON. Born 5 Jan. 1818. Diep 14 Dec. 1891. C. FERDINAND von Roémer was born at Hildersheim, in Hannover, in which kingdom his family occupied a position of some distinction, his father being a Councillor of the High Court of Justice, and his elder brother, Frederick Adolph, being a geologist of repute. Until the age of 18, Ferdinand Romer lived at Hildersheim and received his early education in the Evangelical Gymnasium of that town. In 1836 he removed to Gottingen, where he studied for four years, with the exception of a break of six months at Heidelberg: he had been enrolled as a student of the Faculty of Jurisprudence, but began to attend lectures in natural science, and soon became so interested in this subject as to entirely abandon his legal studies. In 1840 he proceeded to Berlin, and in 1842 the University of that city conferred upon him the degree of Ph.D. in appreciation of a paleontological thesis, “De Astartarum genere.” Dr. Romer remained here for another three years, devoting his vacations to investigations on the older rocks of Western Germany. His main results upon this subject were published in 1844 in ‘Das rheinische Ueber- gangsgebirge.” In the spring of 1845 he sailed for America; he made a very extensive tour through the States, and devoted a year and a half to the study of the geology of Texas, and especially of the Palzeozoic and Cretaceous rocks of the western part of that State. He returned to Europe in November, 1847, and settled at Bonn, where he lived till 1855 as a “ privat-docent,” but occupied mainly in the elaboration and publication of the results of his American expedition. The most important of these was his “ Die Kreidebildungen von Texas” (1852), which, with some smaller papers, have been recently described by Prof. Dumble,* the chief of 1 Grou. Mac. June, 1891, p. 272. * E. T. Dumble, Geol. Surv. Texas, Rep. State Geol. 1889, p. xxii. Austin, 1890. Obituary—Prof. C. Ferdinand von Roemer. ! 93 the new Texan Geological Survey, as affording “a remarkably com- prehensive view of the geology of the State.” In 1855 Romer accepted the Chair of Geology, Paleontology and Mineralogy in the University of Breslau; thenceforth his strictly geological work was mainly devoted to Silesia, his chief results being included in his ‘‘ Geologie von Oberschlesien ” issued as three quarto volumes in 1870. For this work he was knighted and appointed Geheim Bergrath of Silesia. But during the whole of this period he did not rest in peace at home: his travelling instincts, doubtless stimulated by his American experiences, repeatedly drove him to wider fields: thus in addition to tours in England, Belgium, Poland and Austria, he visited Sweden (1856); Norway (1859) ; Russia (1861); Turkey (1863); and Spain (1864 and 1871). In 1859 he was elected a Foreign Member of the Geological Society, by which he was also awarded the Murchison Medal in 1885. The later years of his life were spent at Breslau, busily engaged until the end, which came with sad suddenness just before the attainment of the jubilee of his doctorate ; this his many friends and students were preparing to celebrate, out of respect for his high character and personal popularity, and in gratitude to his power as a teacher. On turning to Ferdinand von Rémer’s work in science, one cannot but be impressed with his wide range of interests and knowledge: it seems doubtful whether he will be longest remembered as a geologist or paleontologist. In the former department he has added greatly to the knowledge of the stratigraphy of America and the countries that he visited; he worked at one time or another on nearly every system from the early Paleeozoic to the Pleistocene ; but probably his work on the Devonian rocks was the most important, ranging as it did right across Europe, from Devonshire to Constantinople. His paleontological works were very numerous and included papers on the Sponges, Graptolites, Rugosa, Ostracoda, Hurypterida, Arachnida, Bryozoa, Lamellibranchiata, Cephalopoda, all classes of Echinodermata; the Ophidia and Mammalia. Many of the genera he added to science were of exceptional interest, such as Stephanocrinus and Dorycrinus, while his discovery of the pinnules in Blastoids, and his work on the anatomy of Cupressocrinus, and the structure of Melonites, were important contributions to morph- ology. His monographs on the Asteroidea and Crinoidea of Bunden- bach, on the Blastoids, and on the fauna of the Bone Caves of Ojcow, in Poland (of which an English translation was issued in 1884), and his “ Die Fauna der silurischen Diluvialgeschiebe von Sadowitz,” were all valuable additions to paleeontological literature. His “ Letheea Paleozoica” issued between 1876 and 1880 as the first part of the third edition of the ‘‘ Lethea Geognostica” (with the early editions of which he had been associated) was a work of vast labour and permanent value. In later years Rémer also wrote on mineralogy, issuing papers on the zinc ores, scheelite, columbite, and the pseudomorphism of cerrusite after cotunnite. But these three subjects did not exhaust his range of interests, for he was well read in literature both modern and classical, and his ‘“‘ Texas, mit besonderer 94 Miscellaneous—Monument to William Smith, LL.D. Riicksicht auf deutsche Auswanderung,” showed his keen sympathy with the political and social problems of the time. Je Wi Ge [As a friend and companion, Dr. Ferdinand Roemer was one of the most cheerful and congenial of men; the Editor is reminded of a delightful fortnight spent in his society in the Hifel, in 1878. His spirits and fun never seemed to become exhausted, and his vast stores of scientific knowledge were always at the disposal of his companions. His memory will be cherished by a large circle of younger men to whom his unvarying kindness will always be re- called with a sense of pleasing regret.—H. W. | MISC hla AW HOUsS- MOSS 6) A Monument to Witu1am Smita, LL.D. One of the most interesting historical collections preserved in the British Museum (Natural History) is the Geological Collection of William Smith, LL.D. This was commenced about the year 1787, and purchased by the Trustees in 1816, a supplemental Collection being added by Dr. Smith in 1818, It is remarkable as the first attempt made to identify the various strata forming the solid crust of England and Wales by means of their fossil remains. There had been other and earlier Collections of fossils, but to William Smith is due the credit of being the first to show that each bed of Chalk or Sandstone, Limestone or Clay, is marked by its own special organisms, and that these can be relied upon as characteristic of such stratum, wherever it is met with, over very wide areas of country. The fossils contained in this Cabinet were gathered together by William Smith in his journeys over all parts of England during thirty years, whilst occupied in his business as a Land Surveyor and Engineer, and were used to illustrate his works, ‘‘ Strata Identified by Organized Fossils,” with coloured plates (quarto, 1816 ; four parts only published); and his “Stratigraphical System of Organized Fossils” (quarto, 1817). A coloured copy of his large Map, the first Geological Map of England and Wales, with a part of Scotland, commenced in 1812, and published in 1815—size 8 feet 9 inches by 6 feet 2 inches, engraved by John Cary—is exhibited in the Geological Department near his collection. William Smith was born at Churchill, a village of Oxfordshire, in 1769; he was the son of a small farmer and mechanic, but his father died when he was only eight years old, leaving him to the care of his uncle, who acted as his guardian. William’s uncle did not approve of the boy’s habit of collecting stones (‘pundibs ”= Terebratule, and “ quoit-stones””=Clypeus sinuatus) ; but seeing that his nephew was studious, he gave him a little money to buy books. By means of these he taught himself the rudiments of geometry and land-surveying, and at the age of eighteen he obtained employ- ment as a land surveyor in Oxfordshire, Gloucestershire, and other Miscellaneous—Monument to William Smith, LL.D. 95 parts, and had already begun carefully and systematically to collect fossils and to observe the structure of the rocks. In 1793 he was appointed to survey the course of the intended Somersetshire Coal- Canal, near Bath. For six years he was the resident engineer of the canal, and, applying his previously-acquired knowledge, he was enabled to prove that the strata from the New Red Marl (Trias) upwards followed each other in a regular and orderly succession, each bed being marked by its own characteristic fossils, and having a general tendency or ‘‘dip” to the south-east. To verify his theory he travelled in subsequent years over the greater part of England and Wales, and made careful observations of the geological succession of the rocks, proving also, by the fossils obtained, the identity of the strata over very wide areas along their outcrops. His knowledge of fossils advanced even further, for he discovered that those in siti retained their sharpness, whereas the same speci- mens derived from the drifts or gravel-deposits were usually rounded and water-worn, and had reached their present site by subsequent erosion of the parent-rock. In 1799 William Smith circulated in MS. the order of succession of the strata and imbedded organic remains found in the vicinity of Bath. His Geological Map of England and Wales is dated 1815. On June 1, 1816, he published his “Strata Identified by Organized Fossils,” with illustrations of the most characteristic specimens in each stratum (4to.). In 1817 he printed “A Stratigraphical System of Organized Fossils,” compiled from the original geological collection deposited in the British Museum (4to.). In 1819 he published a reduction of his great Geological Map, together with several sections across England. These sections have lately been presented to the British Museum by Wm. Topley, Esq., F.R.S., F.G.8., and are exhibited upon the wall - near Smith’s bust in the Geological Gallery (No. 11), see Guide-Book. Mr. Smith received the award of the first Wollaston Medal and Fund in 1831, from the hands of Prof. Sedgwick, the President of the Geological Society—‘“ As a great original discoverer in English geology, and especially for his having been the first, in this country, to discover and teach the identification of strata, and to determine their succession by means of their imbedded fossils.” In June, 1832, the Government of H.M. King William the Fourth awarded Mr. Smith a pension of £100 a year, but he only enjoyed it for seven years, as he died 28 August, 1839. In 1835 the degree of LL.D. was conferred upon Mr. Smith by the Provost and Fellows of Trinity College, Dublin. The highest compliment paid him was that by Sedgwick, who rightly named him ‘the Father of English Geology.” The bust above the case which contains William Smith’s collection is a copy of that by Chantry surmounting the tablet to his memory in the beautiful antique church of All Saints, at Northampton, where his remains lie buried. 96 WMiscellaneous—Monument to William Smith, LL.D. A monument has just been erected by the Earl of Ducie, F.R.S., F.G.S., to the memory of William Smith, at Churchill, Oxfordshire, where he was born; a village already famous as the birthplace of Warren Hastings. The monument is formed of huge Oolitic ragstones of the district, similar to the Rollright stones. The name “ Oolite” was given by William Smith to the rocks of the formation of which the higher grounds in this locality are a part. This view of William Smith’s Monument at Churchill has been prepared from a photograph taken by Lord Moreton, to whom we are indebted for permission to reproduce it here. Tt is a monolith standing on a double base. The lower base is 10} feet square, and 31 feet high, the upper one is 6} feet square, and 24 feet high. The monolith stands 9 feet high above the upper base, and is about 3 feet square. A marble slab is inserted in the side facing the road from Chipping Norton, and bears this inscription :—“In Memory of William Smith, ‘The Father of British Geology’; Born at Churchill, March 28rd, 1769 ; Died at Northamp- ton, August 28th, 1839. Erected by the Earl of Ducie, 1891.” (16d) sadod 8. “JT 290.48NI]L OF, "JOOF ZT OF POUT T ynoqe ‘aTwog “POXTJR ST OWVU OT} TOTAL JO WOISTAIP OT} 0} sSuoraq ylsodap oy} AYO 04 sv 4qnop B sayvorput UOTI0d papeys B 1oqyze (3) W “IN000 OF payoodxa aq Avu quq ‘gov|d qyeyg ye tees Useq JOU Sv powen qisodep olf} JEU SopBoTpUL uoraod popeysun. UB 104fe (4) V "Saag auojsauUVvy uopsiuog ayp ur sabunya po.sagn, Burnoys suoipoag 1v01)04 waasjzou asng % "YU T0log, , Eee ‘ os = =a yi SAO! 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[232] Os TOPPYS ig ees agqum) ~ BS SOQDY YL sir 2S] ONO, $s OP HT 797 crag ical ae == Bsa) a oi == JEQUIT o s US Tet SE Ze Agsiayy \; SOP US. sous cla 4 S2PYUSN= =) 297 012 Page ee wus JSON OLFOUY : “ qnbysy \= = UTP AS Rane Soak EE] emus ae on qbysy \==| ‘7b 222 bis ” 997 “angina 4 "YS YO} “Ys PyI0, Saal eye ee eee LE MPU, LIOLY US PYIODS “US PYIOLCO AS PYIDS "ealV “*BolV “IOUT ‘deyg ‘aTepyoojg «= *|LBpaYG —*UOSTMOD «= “MOTI «= “JOLTSTCT 8T}498 Ys1oqpeg — 9,1. 88019 pue pu 4S JO “M'S yye[er] ADVE VCE DIE NS NTO ‘ZOQI “OVIN “10D THE GHOLOGICAL MAGAZINE. NEW. SERIES.) DECADE MNINE WOE. Ix, No. III.— MARCH, 1892. Or heaeNPAGE, ASE ar @ ieee J.—THe Coniston Limestone Serizs. By J. E. Marr, M.A., F.R.S., Sec.G.S. (PLATE III.) T has long been known that the Coniston Limestone Series of the English Lake District and surrounding areas is separable _ into minor divisions. As a knowledge of these will prove useful in settling the question as to the exact relation between the Coniston Limestone beds and the underlying rocks, no apology seems needed for giving a detailed account of the rocks of this series. The literature of the subject is extensive, but we fortunately possess an excellent bibliography of works referring to the geology of the Lake District, in the appendix supplied by Mr. Whitaker to the late Mr. Ward’s Memoir on the Geology of the Northern Half of the English Lake District. The main outcrop of the Coniston Limestone, as well known, is situated in a line running across the southern half of the district between Shap Wells and Millom, and here the series is succeeded by the Stockdale shales, and underlain by different members of the Borrodale Volcanic Series. Outlying patches occur in the Cross Fell area, the Sedbergh and Ingleton districts, and probably also in the extreme north of the Lake region. § 1. Classification of the Beds. Leaving out of consideration the doubtful beds immediately suc- ceeding the rhyolites of Melmerby (cf. Nicholson and Marr, Q.J.G.S. vol. xlvii. p. 509), and which may possibly form the summit of the Llandeilo Series, the strata which form the subject of this communi- cation belong to the Bala or Caradoc Series, and representatives of the whole of this period are probably present in the north of England. They may be classified as follows :— Ashgill Shales, 50 feet. Ashgill Group ......... Staurocephalus Limestone, 5 feet. Coniston ( AUB natle Beds, 100 feet. LIMESTONE onglomerate, 10 feet, SERIES. Sleddale Group ...... Stile End Beds, 50 feet, with Yarlside Rhyolites above. Roman Fell Group ... Corona Beds, 100 feet. The figures indicate only approximate average thicknesses. The three groups are readily distinguishable by the characters of their DECADE III.—vVOL. IX.—NO. III. 7 98 J. HE. Marr—The Coniston Limestone Series. faunas, that of the lowest group (Roman Fell), and of the highest (Ashgill), being quite different from that of the Sleddale group, which latter has yielded the greater number of fossils recorded in the Coniston Limestone lists hitherto published, though a few species belonging to the other two groups have been incorporated into these lists. Outline-Map of the English Lake- District. EXPLANATION OF MAP. Scale i ns Wl. 27s1es. ° 10 20 Dr= Drygill. SE=Stile End. Ir=Ireleth. S$ =Shap. M= Millom Du=Dutfton. A=Ashgill, Sb =Sedbergh. Sk=Skelgill. St =Settle. § 2. Detailed Description of the Sections.—The fossils of the lowest (Roman Fell Group) have hitherto been detected only in the area of the Cross Fell Inlier, and the beds containing them have been recently described by Prof. Nicholson and myself in the paper referred to above. The thickness of the beds varies, and is difficult to measure owing to the disturbances which the rocks have undergone; but the greatest thickness probably does not exceed two hundred feet. The beds consist of ashes, ashy shales, and nodular black limestones, the latter often composed almost exclusively of the tests of Beyrichia. The table of fossils appended to this paper contains a list of the known forms from the beds of this group. J. EF. Marr—The Coniston Limestone Series. 99 ~The other groups are well displayed in the tract of country between Shap Wells and Millom, and I propose to consider this tract first, commencing at the east end. The most easterly section has been lately described (Harker and Marr, Q.J.G.S. vol. xlvii. p. 272). I would point out here that the limestone referred to the Stile End beds in that description may ‘possibly be a member of the Roman Fell Group. A considerable mass of fossiliferous ashy beds underlies the ‘conglomerate near the Spa Well, and this mass may possibly repre- sent the Stile End beds (the Yarlside rhyolite. being here absent). ‘The limestone above the waterfall at the head of the plantation presents lithologically a closer resemblance to the limestones of the Roman Fell Group than to the less pure limestones of the Stile End ‘Group; but as no fossils have hitherto been recorded therein, the point must remain doubtful. The lower limestone of the Wasdale Head section (Q.J.G.S. vol. xlvii. p. 271) is however, without doubt, the representative of that -of Stile End, and lies immediately below the Yarlside rhyolite. The section in Stockdale Beck is also given in our paper upon the Shap granite (p. 270). I would add a few words to the description given in that paper. The Stile End Series is, as represented in our section, faulted against the rock of the underlying volcanic group. The evidence for this fault we hope to present in a future paper. Above the nodular upper surface of the Yarlside rhyolite a thin band of ash is devoloped in Stockdale Beck. The main mass of the conglomerate above this consists of subangular fragments chiefly of rhyolite, embedded in a slightly calcareous ashy matrix. The highest part of the conglomerate {well seen in Browgill) differs from this. It contains only a few pebbles which are mostly well-rounded, embedded in a tolerably fine calcareous matrix, and it passes up into the limestone of the Applethwaite Series, and is only separated from this series in the present communication on account of its importance as an easily recognizable horizon. The Ashgill Group is faulted out in Stock- dale, but is seen in Browgill below the zone of Diplograptus acuminatus. Few fossils have been obtained from the beds of this section ; though fossils are abundant, they are indifferently preserved. Crossing the valley of Long Sleddale, we find the Coniston Lime- _ stone Series well seen on the hills between that valley and Kentmere, especially near the farm of Stile End. The Stile End beds are here quarried, and consist of grey-green calcareous ashes, weathering yellow, and containing abundant fossils, though these are badly preserved. We have identified :— Lindstremia subduplicata, M‘Coy. Phacops, ct. Hichwaldi, Schmidt. Orthis vespertilio, Sow. calligramma, Dalen. This list, meigre as it is, indicates the close paleontological 100 J. FE. Marr—The Coniston Limestone Series. relationship of the fauna of this series to that of the overlying Applethwaite Series. The last exposure of the Yarlside rhyolite to the west occurs on the moorland above the Stile End beds, and in sections lying further west, the Applethwaite and Stile End beds are separated only by the conglomerate. The conglomerate has not been detected in the Stile End section, but the Applethwaite beds consist, as usual, of ashy calcareous shales, with bands and nodules of impure limestone. In the course of a small stream flowing towards Sleddale, and a little below the watershed, the Staurocephalus Limestone is seen faulted against the Skelgill beds of the Stockdale Shales, so that the Ashgill Shales are here cut out. Many exposures of the Coniston Limestone Series are seen in the small valley running from the Garbourn Pass to Kentmere, occupied by the stream known as Hall Gill, and they contain abundant fossils, but the ground is much faulted, and it is difficult to make out the subdivisions. On Applethwaite Common, also, the conglomerate has not been. detected, and consequently it is impossible to assert positively that the representatives of the Stile End Group are present ‘The Ash- gill beds are found here, but their relationship to the Applethwaite series is not clearly shown. The beds of the latter series, as is well known, here contain abundant fossils. The highest beds of this. series consist here of fairly pure limestones. We now arrive at the important sections of the tract of country lying between Troutbeck and Windermere, the principal one being developed in Skelgill Beck and its tributaries. Here, again, the conglomerate has not been seen, so that, although the beds seen in a quarry north-east of the ‘Upper Bridge’ over this. stream strongly resemble the Stile End Beds, I am not prepared to assert that they belong to that series rather than to the Apple- thwaite series. The beds of the Applethwaite Series consist mainly of calcareous, very fossiliferous, shales, with limestone bands, but a feature is here- clearly seen, which probably characterizes also this series in the more obscure sections to the east. I refer to the existence of a white horny limestone at the very summit of the series. This is seen in the stream at the Upper Bridge, and the Staurocephalus limestone reposes directly upon it. No fossils have been extracted from this bed, but a number of large Orthocerata are seen in cross section in the bed of the beck. Such Orthocerata occur at Keisley, and it is possible that the Keisley limestone, which contains on the. whole the fauna of the Applethwaite Limestone, along with some forms which are not known to occur nearer than the Chair of Kildare, is the highest subdivision of the Applethwaite Series. I wish to discuss this point at some length, because an important physical problem is connected with it. A similar limestone is found in Swindale Beck in the Cross Fell area, and was referred by Prof. Nicholson and myself to the Staurocephalus Limestone, on account of the occurrence of the fauna of that limestone in the associated J. H. Marr—The Coniston Limestone Series. 101 calcareous shales. These shales, however, occur above the main mass of the Swindale Limestone, and on a re-examination of our ‘specimens, I am inclined to think that the lower and purer part of the limestone of that beck, which contains large Orthocerata, like those of Skelgill, along with Illenus Bowmanni, may have to be separated from the upper part which has the true Stawrocephalus Limestone fauna, and correlated with the Keisley Limestone; (a similar limestone occurs below the Staurocephalus-beds of Billy’s Beck). If this be the case, the difficulty connected with the Keisley Limestone would vanish. It would occur under two conditions in the Cross Fell area, first, as a coarsely-crystalline very fossiliferous rock; secondly, as a horny limestone in which the fossils are mainly destroyed. Without offering here an explanation of the frequent occurrence side by side of these two conditions of a -ealcareous deposit, I may point out that they are very frequently found in disturbed regions. I would cite in our own country the Devonian rocks of the neighbourhood of Torquay, where the two ‘varieties are found in the same quarry, also the ‘“ Knolls” described by Mr. Tiddeman (Report International Geological Congress of 1888, p. 319), which are found only amongst the rocks south of the Craven Fault, where there are evidences of great disturbance, and not in the nearly horizontal rocks to the north of the fault. Abroad, a similar case occurs in Bohemia in the Konieprus Lime- stone (EF. f. 2). This limestone is generally a thin, horny, nearly unfossiliferous limestone, but in the “Knoll” of Konieprus, and Mnienian, we find the two varieties side by side. The same may be said of the Leptena Limestone and Klingkalk of Dalecarlia (cf. Nathorst, Aft. ur Foren. i Stockholm Geol. Forhandl. No. 93, Bd. vii. “p. 059), and the Devonian Limestone of the Ardennes. It is not needful to discuss the origin of the nodular masses of -erystalline limestone in this place. The cases cited show that the occurrence of the horny and crystalline conditions of the same limestone in immediate proximity is a common event, and therefore, ‘whatsoever be the true explanation, there is nothing anomalous in referring the Keisley Limestone to the Applethwaite Group, though, ‘as stated in the discussion on the paper by Prof. Nicholson and ‘myself on the Cross Fell area, we only refer the Keisley Limestone ‘and the Dufton Shales (which latter contain the ordinary Apple- thwaite fauna) to the same subdivision of the Coniston Limestone Series. If the suggestion thrown out above should prove to be correct, a further division of the Applethwaite Group may be made into a lower stage characterized by the ordinary Applethwaite fauna, and an upper stage characterized by the fauna of Keisley and the Chair of Kildare. This will probably be finally settled when the Irish beds are re-examined, and in the meantime I include the Keisley fossils and those of the other Applethwaite beds in one list. The Staurocephalus Limestone of Skelgill is succeeded at the Upper Bridge by the Ashgill Shales, which are seen in a very fossiliferous condition on a small knoll by the roadside close to the bridge. The Staurocephalus Limestone is not very fossiliferous in 102 J. EF. Marr—The Coniston Limestone Series. Skelgill ; but on the moorland between this beck and Nanny Lane it has yielded a large number of fossils, especially Cystideans. On the west side of Windermere an important development of the Coniston Limestone Series is seen in the neighbourhood of Sunny Brow. On Limestone Hill, to the west of Sunny brow, a fell-road exposes an ashy calcareous grit with many casts of Lindstreemia, faulted against the Dimorphograptus zone of the Skelgill beds. On the hill to the east of the road, and also in Cross Intake, normal Applethwaite Limestone is seen, with many corals. Although the conglomerate has not been detected here, the character of the ashy grit leaves little doubt that we are here dealing with the repre- sentative of the Stile End Beds, and this was the view taken by Professors Harkness and Nicholson in 1866 (Q.J.G.S. vol. xxiii. p. 482). On the high moorland south-west of Coniston Lake, the Coniston. Limestone Series is seen in numerous exposures, and the Apple- thwaite Series is extremely fossiliferous. Along this tract, as in the case of the Stockdale Shales, the cleavage is much stronger than in the district already traversed. The best section of the lower part of the series is shown at High Pike Haw, near the head of Appletree- worth Beck,, whilst the upper portion is excellently displayed in Ashgill Quarry. At High Pike Haw the discordance of strike between the Constan Limestone Series and the underlying Borrodale volcanic rocks is excellently exhibited, as shown on the map of the Geological Survey.. The lowest rock having the strike of the Coniston Limestone Series. is a purple breccia associated with green ash. Above this are bedded ashy grits and conglomeratic beds, succeeded by a fossiliferous calcareous ash, strongly resembling the Stile End Beds. That it is. actually referable to these beds is shown by the existence of a calcareous conglomerate above it, occupying the same position as at Shap and Stockdale. The conglomerate is succeeded by the Apple- thwaite Beds, which have a well-marked fine ash at the summit. The Staurocephalus Limestone is not seen here, though the Ashgill Shales. come on above the Applethwaite group. In Ashgill Quarry, the Staurocephalus Limestone is seen in the north-west corner, brought against the Skelgill Beds by a cross- fault. The Ashgill Shales form the main mass of the quarry, and are succeeded by the Skelgill Beds, in true sequence, at the top of the quarry-cliff. The relationship between the Staurocephalus. Limestone and the Ashgill Shales above and Applethwaite Beds. below, is also seen at one or two points in the course of Appleites- worth Beck. The section at Millom generally resembles that at High Fike Haw. In Waterblean Quarries the lowest rock seen is a rhyolite of the Borrodale Series. Upon it rest green ashes and breccia, and then a purple breccia, as at High Pike Haw, but the fossiliferous Stile End Beds do not appear to be exposed in this quarry, although a remarkable development of beds, apparently referable to this stage, occurs in Millom Park, north of Beck Quarry, and striking so as. J. E. Marr—The Coniston Limestone Series. 103 to pass under the limestone of that quarry, and above the purple breccia which occurs to the west of this. These Millom Park Beds consist of ashy grits, and one pure quartzose grit, all crowded with fossils. At the base of the Applethwaite Limestone, both at Water- blean and in a small quarry south-west of Beck Quarry, we find the conglomerate, consisting of a calcareous ashy matrix, with the usual subangular fragments. In Beck Quarry calcareous shales of ordinary character yielded the tail of a Phacops (Chasmops), but the greater part of this quarry, and of Waterblean Quarry, is excavated in a mass of crystalline limestone, white, except where stained pink by hematite, greatly disturbed, and resembling the Keisley J.imestone in all particulars, save that it has unfortunately yielded no fossils hitherto. On the east side of the Duddon Estuary, some interesting sections are displayed in the neighbourhood of Dalton and Ireleth. The rocks here are greatly disturbed. The lowest beds yet discovered belong to the Applethwaite Limestone subdivision, and rest some- times on the Borrodale Beds, as near Ireleth, and to the west of High Haulme, sometimes upon the Skiddaw Slates, as in the neigh- bourhood of Crag Wood, west of High Haulme. Near Crag Wood the limestone is usually crystalline, as at Millom, and occurs in a series of remarkable knolls, surrounded by low ground, apparently occupied by shales. At the top of the Applethwaite Limestone we meet with a rock looking like a coarse breccia, succeeded by the Ashgill Group, so that it occupies the same position as the highest ash at High Pike Haw. It is seen in many exposures near High Haulme Farm, and its position is inserted on the Geological Survey Map. Its exact nature is doubtful. Normal Ashgill shales are found above it, and are seen in many exposures to the north of this, as far as Ireleth. Here the interesting section at Rebecca Hill shows the Ashgill Shales, containing in one place a thin band or nodule of much-crushed limestone, succeeded by a fossiliferous ashy deposit (also mapped by the Geological Sur- veyors), and separating the Ashgill Shales from the Stockdale Shales. That it appertains to the former is indicated by the inter- stratification of thin bands of shale, quite indistinguishable from the ordinary Ashgill Shales below. It would seem, therefore, that we have, in the Lake country, indications of volcanic activity through- out the whole period represented by the Coniston Limestone Series. Before leaving this ‘part of the district, I may observe that the limestone of Tottlebank, south of the foot of Coniston Lake, which has sometimes been taken to be a continuation of the Coniston Limestone of the Ireleth region, is really on a much higher horizon, as indicated by the Geological Survey Map, and indeed belongs to the Lower Ludlow beds. ~ Turning to the outlying outcrops of the Coniston Limestone Series, I may revert to the Cross Fell area merely to remark that the Dufton Shales are the equivalents of the Sleddale Group as a whole, and that no conglomerate is found to separate them into Stile End and Applethwaite subdivisions, as has been done along the main outcrop. 104 J. FE. Marr—The Coniston Limestone Series. Further details concerning the beds of this area will be found in the paper by Professor Nicholson and myself which has been alluded to previously. The beds of the Sedbergh District are generally comparable with those of the Cross Fell inlier, 7.e. the Sleddale Group assumes the facies of the Dufton Shales more closely than that of the region around Windermere and Coniston. The Calcareous Shales of Sally Beck south of Ravenstonedale are closely comparable with the Dufton Shales of Cross Fell. The Staurocephalus Limestone has not yet been detected in these regions, though the Ashgill Shales are developed in force ; indeed the characteristic Brachiopod of these shales—Strophomena siluriana, Dav.—is figured in Mr. Davidson’s Monograph from specimens obtained at Fairy Gill. In the centre of the Ashgill Shales a very calcareous grit is found (cf. Marr and Nicholson, Q.J.G.S. vol. xliv. p. 700), as seen at Backside Beck.' The rocks of the Settle district have been referred to by me in a paper published in this Macaztnz (Dee. III. Vol. IV. p. 85). The Applethwaite Group has the facies of the Dufton Shales, though a band of ashes is interstratified with the calcareous shales. The Staurocephalus Limestone has not been detected, though the Ashgill Shales are seen in the stream south of Wharfe, for I have found fossils of this age in the beds numbered “4. Blue, flaggy Brachiopod shales,” in the paper referred to. Though the relationship of the Coniston Limestone Series to the representatives of the Stockdale Shales is perfectly clear in this neighbourhood, the true relations of the former to the Ingleton Green Slates is by no means clear. We have seen that in the central part of the Lake District the Coniston Limestone rests sometimes on the Skiddaw Slates, and not on the Borrodale rocks. Now the only reason why the Ingleton Green Slates have been referred to the Borrodale Series is because they are made up of volcanic detritus, and are immediately succeeded by the Coniston Limestone Series. As the latter fact does not prove their age, we can only point to the occurrence of volcanic detritus as a proof of the correctness of the correlation. The lithological resemblances, however, are very slight, and the volcanic detritus may be derived from rocks of any age. I am inclined to think that these Ingleton Green Slates may be older than any other beds hitherto recorded from the English Lake District, for there are grave difficulties in the way of correlating them with the Borrodale Volcanic Series. 1 Since writing the above I have received the Survey Memoir of Quarter-Sheet 97 N.W. The contemporaneous volcanic series of Backside Beck and Wandale occurs at a higher horizon than that of any of the contemporaneous lavas hitherto detected in other parts of the district, with the possible exception of that running from Kentmere to Shap, and separating the Stile End Limestone from the Apple- thwaite Beds. It seems to occur high up in the Sleddale Group, and it will be remembered that contemporaneous volcanic ashes are found at the very summit of this group in the Coniston area. Mr. Strahan records the occurrence of a grit in the Ashgill Shales on a position corresponding to that of the above-mentioned calcareous grit, both in Taiths Gill and Birk’s Field Gill. The thickness of the Ashgill Shales recorded in Fairy Gill is exceptional. J. FE. Marr—The Coniston Limzstone Series. 105 The last area to which I have to refer is situated in the extreme north of the Lake District. Here a group of fossiliferous beds has been described by Professor Nicholson and myself as occurring at Drygill in the Caldbeck Fells (Guon. Mac. Dec. III. Vol. IV. p. 339). We were led ‘‘to refer the Drygill Shales to about the horizon of the Llandeilo Limestone, or to a slightly higher point in the series.” Since then I have re-examined the fossils, and believe that two of them were wrongly identified (1 may remark that I alone was responsible for this error). The Calymene recorded is more like senaria than cambrensis, and I cannot distinguish the Trinucleus from T. concentricus. 'The other fossils recorded are normal Caradoc fossils, and indeed, looking at the former list dispassionately, one would say that there was a preponderance of Caradoc forms, so that our reference of the deposits to the Llandeilo Series was no doubt influenced by its proximity to the Skiddaw Slates, for we remark that ‘‘they agree most nearly with the Dufton Shales as regards their fauna” .... though “from their general position between the Skiddaw Slates on the one hand and the lavas and ashes (‘ Hycott Series’) of the Caldbeck Fells on the other hand, we should be led to conclude that they occupy a place low down in the latter series.” As we have elsewhere seen that the Coniston Limestone is brought into contact with the Skiddaw Slates, the occurrence of Bala fossils near the Skiddaw Slates is not necessarily to be taken as an indication of the low position of the Drygill Shales, and looking at the fossils as a whole, I am disposed to refer the Drygill Shales to the Coniston Limestone Series, and not even to the lowest position of this, as the fauna is more closely comparable with that of the Dufton Shales than with that of the underlying Corona Beds. Another argument in favour of the occurrence of a Coniston Limestone fauna on the north side of the district is the existence of Cybele near Cockermouth. Mr. Etheridge describes under the name of Cybele ovata a fossil found by Mr. Birkett, at Sandy Beck, near Wood (cf. Memoir by Rev. J. C. Ward, “The Geology of the Northern Part of the English Lake District,’ Appendix A, p. 112). Unfortunately, as I learn from Mr. Postlethwaite, the specimen was not found in situ, but occurred in a pebble; still, as this can hardly have been brought from the south side of the district, it probably indicates the existence of rocks with Cybele on the north side. Now this genus is not found in Britain below the Bala rocks, though it occurs at a lower horizon in Russia and Sweden. I have examined Mr. Birkett’s specimen (now in the Keswick Museum), and it is very near to, if not identical with, Cybele Loveni, Linns., a common Coniston Limestone form. § 3. Results of the Examination of the Series. The various equivalents of the Coniston Limestone Series have een discussed by myself and others in earlier communications, and it is only necessary here to give a general summary of the conclusions. In the description of the Cross Fell Inlier by Professor Nicholson 106 J. E. Marr—The Coniston Limestone Series. and myself, we compared the Roman Fell Beds with the Beyrichia Limestone of Scandinavia and the Trenton Limestone of North America, and suggested their correspondence with the Ardwell Beds. of the Girvan area. The peculiar fauna will probably be discovered elsewhere, and should be searched for amongst the shales below the Bala Limestone of North Wales, and among the fossiliferous beds of Tyrone. The well-known fauna of the Sleddale Group! has been 80 frequently and successfully compared with the similar fauna of the Bala Limestone, and its equivalents in the British and foreign Lower Paleozoic areas, that it is unnecessary to discuss the identity in this place, for it is now generally recognized. The relationship of the Dufton Shales to the Trinucleus Shales on the one hand, and the normal Sleddale Beds on the other, has also been commented on in a previous communication. The very abrupt change from the Lake District type of the Sleddale Group to the Cross Fell type in the short interval occupied by the newer beds of the Hden Valley, is a point that requires notice. JI have already remarked on the likeness of the Keisley Limestone to that of the Chair of Kildare. A re-examination of the Bala Beds of Kildare and Tyrone is very desirable, as several stratigraphical horizons appear to be represented there, judging from the fossils which have been obtained. The equivalents of the Staurocephalus Limestone occur in many parts of Britain, as well as in Scandinavia. Indeed, it is at first sight surprising to find how constant are the lithological characters of this green argillaceous limestone, when we remember that it is seldom more than a few feet in thickness. It retains its peculiar character in the south of Scotland (the “Starfish-bed), North Wales (Rhiwlas Limestone), Pembrokeshire (Staurocephalus Limestone), Ireland, and Scandinavia. An examination of the fauna fully accounts for this constancy of character. Though it contains many species common to the overlying Ashgill Shales, there is a marked change betwixt the organisms of this limestone and those of the underlying Sleddale Group, and very few species are common to the two. Insignificant, therefore, as the thickness of this deposit is, the time taken for its 1 Tt may be remarked that sufficient proof has not been offered as to the distinct- ness of the Stile End Beds from the Corona Beds of the Cross Fell area. The somewhat meagre list of Stile End fossils previously given does not bring out the marked contrast between these beds and those of the Roman Fell Group. Not only is the peculiar fauna of the Corona Beds entirely absent from the Stile End deposit (and fossils, though ill-preserved and belonging to few species, are very abundant at Stile End), but the Stile End rocks are crowded with casts of Lindstremia, both in the region where the Yarlside rhyolite separates them from the Applethwaite Beds, and in the region further west. No Lindstremia has yet been detected in the Roman Fell Beds. In the neighbourhood of Coniston the Stile End Beds contain numerous fossils, which, as is usual with the beds of this series, are preserved as casts only, but fragments of several fossils generically identical with those of the Applethwaite Beds are easily discoverable, and, as far as one can judge, they are also specifically identical. ‘Though it is just possible, therefore, that these Stile End Beds are actually representatives of the Roman Fell Group, all the evidence points to their being newer. ; ides J. HE. Marr—The Coniston Limestone Series. 107 accumulation was probably very great, and its characteristic organisms had time to become widely dispersed. The Stawrocephalus fauna is. far from being fully described, and few deposits would better repay a close examination by a local geologist. The most fossiliferous localities yet discovered in the north of England are the west corner of Ashgill Quarry, the moorland between Skelgill and Nanny Lane, Troutbeck, and, in the Cross Fell area, Swindale Beck and Billy’s. Beck. The Echinoderms and Crustacea of the bed are particularly remarkable. The overlying Ashgill Shales and their equivalents are fairly well known in those regions where there is a passage betwixt the Ordo- vician and Silurian strata. In Scotland we have similar shales above the starfish-bed in Lady Burn. In North Wales blue shales ap- parently referable to this horizon occur between the Bala Limestone and the Hirnant Limestone. In South Wales the Redhill beds con- tain a similar fauna, and occupy the same position. In Sweden the resemblance of the shales lying between the Stawrocephalus Limestone and the representatives of the Stockdale Shales to our Ashgill Shales is very noticeable. In North Wales the Hirnant Limestone is generally placed at the summit of the Ordovician beds, and Mr. T. Roberts and myself have- also placed the Slade Beds of South Wales in a similar position. In Scandinavia, Tullberg assigns the lowest Graptolite-bearing stratum above the beds containing normal Bala fossils to the Ordovician system, on account of the absence of Monograptus. As it is succeeded by beds containing Dimorphograptus, it is probably the equivalent of the zone of Diplograptus acuminatus of the Birkhill (Skelgill) shales, and the same may be true of the Hirnant Limestone and the Slade Beds. The truth is that where we have an unbroken suc- cession between Ordovician and Silurian rocks, the exact line of demarcation must be purely conventional. 5 In the table! (Plate III.) showing the variations of the different members of the. Coniston Limestone Series, no attempt is made to give an exact representation of their actual thicknesses in various. localities, for in the case of beds which have been so disturbed, such thicknesses, as taken by measurement on the ground, would probably be incorrect. Nor is this a matter of much importance in a case where volcanic outbursts are clearly seen to determine to a very large extent the changes of thickness, when the beds are traced along the outcrop. It is clear that in such cases, the position of former continental masses cannot be ascertained from a study of the direction of thinning out of the beds. The Ashgill Shales, however, do not show any great amount of volcanic material, but appear to be normal sediments. If the thickness assigned to these beds in Fairy- gill, in the Sedbergh district, be an approximation to their original thickness, this would show an expansion of these beds when traced eastwards, and this agrees with the observations made by Professor 1 Tn this table, whilst the lava-flows and more prominent ashes are inserted, no attempt is made to indicate the finer volcanic material mixed with the Calcareous- muds of many of the beds of the Roman Fell and Sleddale-Groups. 108 J. E. Marr—The Coniston Limestone Series. Nicholson and myself in the case of the Stockdale Shales, which furnish much more precise data for accurate measurement. It is possible, therefore, that land lay to the south-east of the Lake District at the end of Ordovician and commencement of Silurian times, and this is supported by an examination of higher Silurian strata. The consideration of the beds above the Stockdale Shales must, however, be reserved for a future occasion. § 4. Fossils of the Coniston Limestone Series. I. Roman Freti Grovp. The smaller Crustacea are omitted in this list. Conchicolites gregarius, Nich. ... A teleocystites, sp. Homalonotus rudis, Salt. ... Lingula tennigranulata, M‘Coy Strophomena grandis, Sow. Orthis testudinaria, Dalm. Trematis corona, Salt. . Ambonychia gr yphus, Portl. Bellerophon acutus, Sow. —— bilobatus, Sow. . . Actinoceras pusgillensis, Foord.. Cyrtoceras?... ... ove They require revision. Pusgill ; Roman Fell. Roman Fell. Roman Fell. Pusgill ; Roman Fell ; Swindale ; Pusgill. Roman Fell. Pusgill ; Harthwaite Beck; Roman Fell. Pusgill; Roman Fell. Roman Fell. Pusgill ; Roman Fell. Roman Fell. Roman Fell. Swindale. Il. SneppaLe Grovp. The fossils from the Dufton Shales, and Keisley Limestone are included in the list. They will be recognized from the localities attached. The Corals are omitted, -as the Coniston Limestone Corals are now being examined by Prof. Nicholson. Polyzoa also want revising. Dicellograptus complanatus, Lapw. ... anceps, Nich. ae Diplograptus socialis, Lapw. Buses truncatus, Lapw. ; Tentaculites anglicus, Salt. Ateleocystites, a Acidaspis, N.sp. . Sad es eo Sac Amphion, n.sp. Ampyx tetr agonus, Ang. tumidus, Forbes : Beyrichia conplicata, Salt... Calymene Blumenbachii, Brong. var. Caractaci, Salt. ... —— senaria, Cour. ... Cheirurus bimucronatus, Murch. clavifrons, Dalm. ? ... Cybele Loveni, Linurs. —— verrucosa, Dalm. Cyphaspis, cf. triradiatus, oa: Cyphoniscus socialis, Salt.. : Dindymene, n.sp. Lncrinurus multiplicatus, ‘Salt... multisegmentatus, Portl. ? Harpes Doranni, Portl. LHomatonotus punctillosus, cone Sedqgwicki, Salt. Illenus Bowmanni, Salt. cancrurus, Salt..., 2... .0. ev. Swindale. Norber; Skelgill ? Swindale. Hurning Lane, Dufton ; Norber. Troutbeck ; Coniston ; Norber. Norber ; Wharte. Pusgill; Applethwaite. Troutbeck. Pusgill; Billy’s Beck. Keisley. Applethwaite ; Coniston. Coniston ; above Rother Bridge. Horton ; High Haulme; Coniston ; Apple- thwaite; Swindale. near Dent; Keisley. Keisley. Keisley. Applethwaite ; Dufton; Norber. Kavenstonedale ; Helm Gill; Swindale ; Pusgill ; Applethwaite ; Coniston. Keisley. Keisley. Norber. Barking ; Dent. Sunny Brow. Coniston. Keisley. Ravenstonedale. Coniston; Applethwaite; Swindale. J. E. Marr—The Coniston Limestone Series. Illenus cf. conifrons, Billings ... Davisiz, Salt. Rosenbergi, Kichw. ... Lichas laxatus, M‘Coy laciniatus, Dalm. .. Phacops Brongniartiz, Portl. —— cf. brevispina, Schmidt .... — (Pterygometopus) sp.... cf. Hichwaldi, Schmidt ... Phillipsinella parabola, Barr. eo) Primitia strangulata, Salt. Remopleurides Colbii, Portl. — cf. longicostatus, Portl. Spherexochus boops, Salt.. caluus, M‘Coy Trinucleus ee ole Eaton .. seticornis, His. ... Turrilepas, sp. Youngia (Linurs. non R. J ones) | trispinosa, Nich. and Eth. jun. Atrypa expansa, Linnrs. Leptena transversalis, Dalm. Lingula ovata, M‘Coy Orthis Actonie, Sow. — bidens, Salt., MS. — biforata, Schloth. —— calligramma, Dalm.... —— elegantula, Dalm. flabellulum, Sow. — insularis, Kich.... — porcata, M‘Coy... ... spiriferoides, ee Ws testudinaria, Dalm. . vespertilio, Sow. Ee Strophomena conrugatela Dav. deltoidea, Cour... expansa, Sow. pecten, Linn. ... rhomboidalis, Wilck. Loxonema obscura, ’Portl. Cyrtoceras sonax, Salt. Orthoceras, ct. elongato-cinctum, Portl. Orthoceras velatum, Blake.. Trochoceras cornu-arietis, Sow. 109 Keisley. Troutbeck; Wharfe. Long Sleddale ; Troutbeck; Sunny Brow. Pusgill; Keisley. Coniston; Keisley. Applethwaite; Coniston; Swindale ; side Beck. Coniston. Coniston; Applethwaite ; Norber. Norber. Applethwaite ; Coniston. Swindale; Applethwaite. Keisley. Applethwaite ; Keisley. Pusgill. Applethwaite ; Norber. Back= Stile End. Coniston. [Norber. Pusgill; Hurning Lane ; Pusgill; Hurning Lane. Keisley. Coniston ; Hilton Beck ; Norber; Wharfe. Coniston ; Applethwaite. High Haulme; Coniston ; Helm Gill; Keisley. Helm Gill. ‘ Ravenstonedale; Helm Gill; Troutbeck. Helm Gill; Troutbeck; Stile End. High Haulme; Helm Gill; Troutbeck. Applethwaite ; Skelgill. Coniston; Troutbeck. High Haulme; Helm Gill; Troutbeck ; Troutbeck. [ Keisley, Pusgill; Harthwaite Beck; Keisley. Troutbeck ; Coniston; Stile End; Dufton; Keisley. [ Keisley. Keisley. Keisley ; Harthwaite Beck. Ravenstonedale ; Troutbeck. Helm Gill; Troutbeck; Coniston. Keisley. Helm Gill. Keisley. 9 Applethwaite ; Troutbeck ; Coniston. IIIa. SravrocerHatus Limestone. Echinospherites arachnoideus, Forbes balthicus, Kichw. Davisii, M‘Coy... Agnostus trinodus, Salt. ?... Acidaspis Calymene Blumenbachii, Brongn. Lichas laciniatus, Wahl. Ogygia... Phacops apiculatus, Salt. eucentra, Ang. ... Jukesii, "Salt. ea Phillipsinella parabola, Barr. Staurocephalus globiceps, Portl. mammosus, Salt. MS.? ... Swindale. Troutbeck. Troutbeck, Troutbeck. Troutbeck, Swindale. Ashgill. Swindale, Ashgill. Ashgill; Troutbeck, Ashgill ; Troutbeck. Swindale. Swindale; Troutbeek. Troutbeck ; Billy’s Beck ; Swindale. 110 Horace B. Woodward—On Landscape Marble. Turrilepas ... ss. se. ose wee oes Ashgill; Troutbeck ; Swindale. Shenidium, D.Sp.... 2. .s ser wee > ese Billy's Beck. Holopea ... pee |) sesh wie EID GK, Orthoceras vagans, ‘Salt. ... ... ... ‘Troutbeck. IIIs. Asuerti SHaALezs. Cornulites ... ss. cos eee ove eee Skelgill; Backside Beck. Myelodactylus? ... ws os ..» «se Backside Beck. Glyptocrinus se ve nee nee aes Skelgill. ‘Ogygia ses hee cen, AOBEDECK. Phacops apiculatus, Salt. ... ... ... Rebecca Hill; Troutbeck. eucentra, Ang. ... ... Ashgill; Troutbeck. Phyllopora Hisingeri, M‘ Coy ... Backside Beck. ‘Orthis actonia, Sow.... ... s« «» Skelgill. — biforata, iSehlot i; sees: Skeleill; Ashgill; Swindale; Backside Beck. calligramma, Dalm.... ... ... Skelgill. — elegantula, Dalm. ... ... ... Skeleill ; Swindale. — protensa, Sow.... ... ... « Skelgill; Ashgill; Swindale; Backside Beck. — testudinaria, Dalm.... ... ... Skelgill; Applethwaite. vespertilio, Sow. ... ... ... Skelgill. Strophomena siluriana, Day. ... ... Troutbeck; Skelgill; Ashgill; Rebecca Hill; Swindale; Fairy Gill; Backside Beck. Theca triangularis, Portl.... ... ... Skelgill. TBEU BORON 0 o.0 ne, doe! one vee), ALL. IJ.—Remarks ON THE FormMATION OF LANDSCAPE MARBLE. By Horace B. Woopwarp, F.G.S. HE Landscape Marble or Cotham Stone is one of the best known of our English ornamental rocks. Polished slabs of it may be seen in most. museums; and there are fashioned out of it paper- weights, ring-stands, and other useful objects, which may be purchased on. Clifton Down and elsewhere. This stone came into notice when it was quarried, together with other beds, near Cotham House, on the northern side of Bristol ; and it was described in considerable detail in 1754 by Edward Owen, who then gave it the name of ‘‘Cotham Stone.” ! It is a hard, close-grained argillaceous limestone, which breaks with a fracture almost as conchoidal as that of flint; and it is characterized by dark arborescent markings which pervade the stone. These markings rise from a more or less stratified base, and terminate upwards in the wavy banded. portion of the limestone, which varies from one to about nine inches in thickness. Thus when slabs, cut at right angles to the planes of bedding, are polished, there may often be discerned (with the aid of the imagina- tion) a landscape with a prominent row of trees and bushes, with clouds above, and perhaps the semblance of water in the foreground.? The lower surface of the limestone is even, though sometimes in small masses of the rock it is gently curved ; the upper surface is corrugated, and the irregularities appear to correspond in many instances with the original planes of deposition, for thin layers that 1 Observations on the Earths, Rocks, Stones, and Minerals, for some miles about Bristol, etc., 8vo. London. 2 An illustration of the Landsc ‘ape Marble was published in the Proc. Geol. Assoc. vol. i, p. 209. : Horace B. Woodward—On Landscape Marble. Ill coincide with the uneven surface may be split from the rock. In other instances the ridges on the surface are curiously interlaced, forming a kind of ‘rustic work” that is prized for rockeries. It seems likely that the upper surface of the stone is largely due to the shrunken state of the calcareous mud from which the Cotham Stone originated. So far as I know, wherever the crinkly surfaces and the arborescent markings are present, the limestone occurs in isolated and lenticular masses; and these are sometimes less than a foot across, sometimes three feet or more. Where the stone, or its equivalent, occurs as a fairly persistent layer, it maintains its compact character, it is banded and evenly bedded, but the arborescent markings are wanting. While the Cotham Stone is present in a number of localities from Bristol to Uplyme in Devonshire,' yet in many sections exposed over that area it has not been recognized or but doubtfully identified, partly because of its impersistent nature, and partly because it may be represented by a layer without arborescent markings.: This is the case also in the country north of Bristol. It is interesting to find that this layer of limestone extends, even in interrupted masses, over so large an area, and it is noteworthy that wherever the characteristic Landscape Marble has been observed, it occupies a position in the Rhetic Beds, at or near the junction of the Black Avicula-contorta Shales with the overlying beds of White lias. The limestone thus forms an horizon of some service to the geological surveyor, and it may be tracked across many_a ploughed field between Bath and the Mendip Hills. The finest examples of the stone that I have seen, were opened up during the construction of the Midland Railway between Bath and Kelston. To its stratigraphical position the Cotham Stone may in some measure owe its peculiar characters, occupying as it does an inter- mediate place between dark argillaceous sediments and almost pure calcareous mud. In some localities a few inches of dark clay may be found above the Stone, but usually it is overlaid directly by the pale marls and limestones of the White Lias. It marks a stage when this calcareous sediment was commingled with a slight amount of dark mud deposited in occasional films. Thus an ordinary banded limestone was produced in many places, as seen in the railway- cutting -at Cossington, between Bridgewater and Edington, at Aust, and at Lassington near Gloucester. Beds of this character, although they exhibit no arborescent markings, are often spoken of as “Cotham Marble,” because they occupy the same stratigraphical position. Between this ordinary banded limestone and the distinctly ar- borescent types, all sorts of intermediate varieties may be found ; but as most of these varieties are not ‘ornamental,’ they are regarded as unsuitable for polishing, and do not come much into notice. Occa- sionally in less compact rocks, where darker and lighter layers of material are present, arborescent markings may be found; this is the case in the ‘ Hstheria-bed,’ which occurs in the upper part of the 1 See Dr. Wright, Guou. Mac, 1864, p. 291. 112 Horace B. Woodward—On Landscape Marble. Rheetic Beds at Garden Cliff, Westbury-on-Severn; and it is an exceedingly irregular and nodular limestone. In other formations I have met with similar phenomena. In the Lower Purbeck Beds at Durlston Bay, near Swanage, there is a thin layer of limestone that presents the same corrugated and mammil- lated surface as the Cotham Stone, and it exhibits obscure arborescent markings. Again at Rounden Wood near Battle, a layer presenting like characters, occurs also in the Purbeck Beds. In the same dis- trict near Battle, there is a bed of more or less nodular limestone called the ‘Cutlets,’ and this sometimes possesses curious irregular bands of light and dark grey tints, that form a sort of intermediate stage between even banded limestone and Landscape Marble. There is a specimen of this rock in the Museum at Jermyn Street. Another illustration 1 have met with in the Inferior Oolite of Charlcombe, near Bath, where there occurs a bed of compact brown limestone, banded at the base like the Cotham Stone, and becoming nodular (and in this case also somewhat concretionary) above; and this rock exhibits faint resemblances to arborescent markings. For want of a better explanation I have elsewhere compared the arborescent markings in the Landscape Marble with the dendritic infiltrations of manganese-ore, etc., so commonly met with on the surfaces of rocks, sohceher along joints or bedding-planes.’ I now think there is no particular connexion between the phenomena of infiltration and the production of the Landscape Marble. The ferruginous infiltrations that produce irregular bands of colour throughout the mass of many rocks, present no close resemblance to the features of Landscape Marble. Some of the appearances met with in the fissile limestone known as ‘ Florentine Slate’ and ‘ Ruin Marble,’ are due to infiltrations of oxide of iron that permeated the stone probably after consolidation ; while the rock itself, thus irregu- larly banded, was subsequently fractured, and portions of it shifted by minute faults that have given the sharp outlines to the “ ruins.” It may be mentioned that other beds of limestone above the Cotham Stone, and as high as the ‘Sun Bed,’ which is locally the top layer of the White Lias, occasionally present irregular and corrugated surfaces, but these occur in homogeneous limestone, and no arborescent markings are exhibited. The fact indirectly lends support to the view that the arborescent markings of the Cotham Stone are contemporaneous and not due to subsequent infiltration. There is no evidence to support the notion that gaseous emanations, such as might have arisen from the black mud of the Avicula contorta Shales, had anything to do with the formation of the Landscape Marbles. This notion was to a certain extent suggested by E. Owen, who thought the arborescent markings were produced by the escape of imprisoned air; but had such agents been at work the markings would not be confined to the nodular masses of rock, and they would extend upwards through the base of the limestone. It appears to me that the arborescent markings were produced 1 Geol. E. Somerset, etc. (Geol. Survey), p. 70; and Geol. England and Wales, ed. 2, p. 244. t Horace B. Woodward—On Landscape Marble. 113 during the consolidation of the stone, and more particularly by the shrinking of its upper portions. In this way, and while the mud was still in a more or less pasty condition, one or more of the dark films in the banded mass were disarranged and dispersed in arborescent form in the slowly setting rock. The features dis- played in different specimens of the Landscape Marble suggest that sometimes an upper and sometimes a lower film of dark mud was dispersed. ‘There are specimens likewise that exhibit a double landscape, one above the other. An example is figured by EH. Owen (op. cit. pl. i. p. 163), and similar specimens are preserved in the Museum of Practical Geology. In these instances there seems evidence of a prior consolidation in the rock, followed by more calcareous mud, the whole ultimately coalescing to form one layer of limestone. It may be that the production of the isolated masses of rock with their irregular upper surfaces, was attended by some pause in the deposition of sediment, and by exposure of the layer to the sun’s rays. There is no doubt that such circumstances took place during the Rhetic period; and the rolled lumps of contem- poraneous limestone met with in the White Lias near Lyme Regis and near Harbury are suggestive of such exposure during the later stages of the period.!. Thin veins of calc-spar occasionally penetrate the ‘inferior kinds’ of Landscape Marble, and these fill cracks that were perhaps the final result of consolidation: the mass of the stone being sometimes found in a minutely faulted condition. Under the microscope the dark arborescent portions appear sharply defined from the main mass of the Cotham Stone, and some tiny dark portions are seen to be isolated. Mr. J. J. H. Teall, who kindly examined the rock, states that it is ““mainly composed of extremely fine granular calcite, and that it contains a few very small grains of quartz. In the part which shows the characteristic markings there are patches of clear and sometimes coarse-grained crystalline calcite.” These facts are not inconsistent with the view that the appearances are due to the partial intermixing of the dark and light layers of mud during consolidation, albeit attended by some crystallization of calcite. The evidence here brought forward is essentially stratigraphical ; but if the suggested explanation be true, it serves to indicate the kind of re-arrangement that may take place when a pasty sedimentary mass solidifies in a somewhat irregular manner. It has been noticed that the upper surface of the Cotham Stone is generally corrugated, but that it is sometimes formed of branching or interlacing ridges. These latter may be connected with phenomena of segregation. The segregation and concentration of calcareous material is shown in the irregular and nodular character of some of the Lias limestones, and in other formations where cement-stones and septaria occur. Some nodules of “race” and ironstone exhibit mammillated surfaces, when there is no evidence of concretionary action such as would be indicated by the deposition of successive coats of mineral matter. 1 Proc. Geol. Assoc. vol. xi. p. Xxx, DECADE III.—VYOL. IX.—NO. III. 8 114 L. W. Fulcher—On the Hirnant Limestone. The process of formation of the Landscape Marble seems to me to have been mainly mechanical, although, as might be expected, there is evidence also of chemical change. In attributing the corrugated surfaces to the shrinking of the calcareous mud, I may have appealed too strongly to mechanical causes, as apart from the obscure processes of segregation, or even of concretionary action. The facts, however, show the connexion between the arborescent markings and the corrugated and lenticular masses of banded lime- stone; and they support the contention that the markings were produced by changes amid the variously tinted calcareous mud during its solidification. II]l.—Norer on tHE ComposiITion AND STRUCTURE OF THE HIRNANT LIMESTONE. By L. W. Futcusr, B.Sc., F.C.S. (PLATE IV.) URING the summer of 1890, Professor Cole and I, whilst geologising in North Wales, were led to examine the Hirnant Limestone. Since then the further examination in the laboratory of the specimens collected by myself have revealed some remarkable characteristics which, as they are as yet undescribed, I think are worthy of notice. The specimens on which the following observations have been made were obtained from a small cutting opposite to the farm named Cwm-yr-aethnen, in the valley of the Hirnant, which descends towards Bala Lake. The limestone occurs here between two beds of fossiliferous slate. The exposure is very small, and being con- siderably overgrown, it was only by careful search that we suc- ceeded in finding it. The Survey Memoir! mentions that an outcrop occurs at Trum-y-gwrageda, and also that loose blocks were found by Sedgwick at the Bwlch-y-groes; but after a careful search we failed to find it at either of these localities. It is necessary for me to add here that Iam greatly indebted to Prof. Cole for much valuable advice and criticism of the facts observed as well as for the loan of some material, and I hereby tender him my best thanks. The rock is described in the Survey Memoir as “ fossiliferous, black and pisolitic, the concretions being about the size of small grains of barley.” It is a very tough rock, and in hand specimens from the above- mentioned locality the black grains, which are mostly ellipsoidal in shape, are from 1mm. to 3mm. in their longest diameter, and are somewhat sparsely scattered in a crystalline matrix, that is to say, they are not so crowded together as in the case of an ordinary piece of oolite limestone. The centres of the grains often show the bright cleavage face of a calcite crystal. An analysis of the rock reveals the interesting fact that the black- 1 Ramsay, Geology of North Wales, Mem. Geol. Survey, vol. iii. L. W. Fulcher—On the Hirnant Limestone. 115 mess of the grains is due to carbon in an amorphous form. The following were the numbers obtained by a quantitative analysis :— Insoluble residue (other than carbon) ... ... 18°35 Carbonien ee .t atc. (sce lec: | Renee! SoalestS fs); (Colne) gu G86 gon cco 00050. be 227 IBEO ead) edo Boe. P aeB eo 1°57 CaO 42°85 MgO 1:05 COREY Se. 34°15 P205 1:35 H2S04 06 100°83 These figures correspond to a total percentage of CaCO,=72'82, MgC0;=2:2, and FeCO,=2°43. It also gives off a trace of SH, when dissolved in hydrochloric acid. The insoluble residue (including the carbon) contains approximately carbon 7 per cent.; SiO, 77 per cent.; and Fe,O,-+ Al,O, 11 per cent.; the remaining 5 per cent. containing lime, ete. The specific gravity of the rock varies slightly in different speci- mens from the same locality. Thus two determinations kindly communicated to me by Prof. Cole gave 2-604 and 2:67, while another for which I am indebted to Mr. Hume gave 2-642. These differences are readily explained by the variation in composition of this rock, even at distances of a few inches in the same specimen, which is shown when sections are observed under the microscope. Reference is made to this further on. When a piece of the rock is treated with dilute hydrochloric acid, ‘the calcite is gradually dissolved and the grains are left as little black hollow ellipsoids, together with a quantity of fine sand and carbon in powder. These black grains, when pressed by the finger on a piece of paper, soil both the paper and the fingers just like ‘soot would do. But they are not wholly composed of carbon ; for on ‘heating them to redness in a platinum capsule, they turn of a reddish- ‘brown colour, still retaining their shape, though all the carbon has been burnt off. It is easily seen now by applying the usual tests that these residues are composed of silica coloured by a little oxide ‘of iron. Some of the black grains mounted in Canada balsam show -a concentric structure, but this is much better studied in sections of the rock itself. Amongst the residue of a piece of the rock about 14 inches square Talso obtained some fragments of a very fine micaceous sandstone, the largest of which measured 11 x 8 mm. This particular fragment also had some very regular black markings on its surface, which I thought might possibly be leaf-scars; but on submitting the frag- ments to Mr. Boodle, this gentleman gave his opinion against this idea, but suggested that they might possibly be aggregations of fine sand around small vegetable filaments, as the carbon in the fragments seemed to occupy the hollows of very small canals. Of course this point cannot be settled until large quantities of the rock are dis- solved, so that a good many of these fragments can be examined. 116 L. W. Fulcher—On the Hirnant Limestone. At present I have not the material for this purpose, but I have: thought it well to mention the fact of the peculiar aspect of these sandstone fragments, as Ordovician plants are so rare that any in- dication of their existence is naturally a matter of interest. I may add that a section which I had prepared.of the fragment did not reveal any noteworthy characters under the microscope. When a section of the rock is examined under the microscope, we see the grains lying in a crystalline matrix of calcite (Pl. IV. Figs. 1-2, for the drawings of which I.am indebted to the kindness of Mr. E. W. Wetherell). The centre of the grains consists usually of granular calcite, and in some cases has the form of a figure of 8, but is generally rather irregular in shape. Occasionally the nucleus is the fragment of an organism or a grain of sand. Around the centre the carbon appears as a series of opaque concentric rings, though now and then patches are seen to have been torn away in the pre- paration of the section. Ina few cases the carbon seems to fill up the- whole of the interior of the grain, but this is probably due to the fact that the centre of such grains has not been cut through. Externally the grains are seen to be increased in the direction of their longer axes by a secondary development of a fibrous-looking mineral. This statement, however, must be modified. In all the sections which I had prepared from my own specimens this secondary mineral appears ; but Prof. Cole has lately lent me a slide in which it is. entirely absent, so that the alteration is possibly only local. The fibrous-looking mineral from its optical properties seems to be a chalcedonic variety of silica. Under a high power the fibrous appearance is seen to be due to a number of thin elongated prisms which are apparently quartz. This mineral is itself bounded by a band of almost opaque material which sometimes includes carbon. There are often three or four bands of chalcedony separated from each other by a layer of the dusty material. There is very rarely a radial grouping in the grains as in some Oolites, nor does there appear to be any such structure as the recently described Girvanella.' The grains give no black cross between crossed Nicols. The matrix in which the grains are embedded is seen to be ordinary crystalline limestone, but it contains here and there frag- ments of organisms (Polyzoa), and also small irregular grains of quartz, which are by no means regularly dispersed, being in some places much more numerous than in others. These quartz grains often contain moving bubbles. It is also to be noticed that occasionally an extremely thin band of secondary calcite traverses the whole section, penetrating right through the grains. A section which has been mounted in Canada balsam, and then etched with hydrochloric acid so as to dissolve the calcite before being covered up, shows more clearly the concentric structure of the grains and the outer coating of chalcedonic silica which they possess. It will be observed from the above description that the rock is somewhat analogous in structure to the Cleveland iron ore,’ ae u Withers, Grou. Maa. 1889, p. 196. * Sorby, QJ. G.S. vol. xxxy. (1879) Proce. p. §4. G. W. Card—Flexibility of Rocks. 117 ‘Northampton iron ore,! and the pisolitic iron ore of Cader Idris.? It ‘differs from all these, however, in the fact that the grains have a coating of carbon, and in the absence of the oxides of iron which ‘form the chief constituent of the latter. It resembles all the above- ‘mentioned rocks in the fact that the grains contain a skeleton of silica, -and further in the presence of ferrous carbonate and phosphoric acid. ‘It is most probable too that the silica skeleton in the case of the ‘Hirnant limestone is due to the infilling of a cavity produced by ‘solution of the calcium carbonate of the grains, which solvent action “was prevented from extending inwards by the insoluble nature of the carbon. On the whole it seems that the rock owes its distinctive characteristics to vegetable agency,—the peculiar form of the carbon as well as the other chemical constituents lending evidence in sup- ‘port of this view. This evidence would be much strengthened if the sandstone residues described above should turn out to be a result of ‘the existence of plant life as suggested. JV.—On Tue Furxipiniry or Rocks; with SPECIAL REFERENCE TO THE FLEXIBLE Limestone oF DurHam. By Grorce W. Carp, A.R.S.M.; Assistant Demonstrator of Geology at the Royal College of Science, London. TW\HE existence of rocks possessing, when the lamine are not too thick, the property of flexibility has long been known. Upon flexible sandstone (‘‘Itacolumite”) a great deal has been written at different times, and of late years important work has been done ‘which renders it necessary to greatly modify the opinions formerly held with regard to this rock. Notwithstanding the interest which is attached to the subject, it is one very much neglected by our text- books, the British, either ignoring it altogether, or treating it with the utmost brevity, the German, while sometimes referring to it at considerable length, do not do more than enunciate the old views. ‘To Prof. Judd—who has kindly aided me with advice, and by afford- ing facilities for preparing this paper—I owe the suggestion that it ‘would therefore be useful to give a résumé of the present state of our knowledge upon the flexibility of rocks in general. This paper will accordingly be divided as follows :— 1. An account of the Durham Limestone. 2. Some remarks upon Flexible Sandstone. 3. A comparison of the two rocks. - 1. The Flexible Limestone of Durham.—My attention was first directed to the existence of this rock by Mr. H. B. Woodward’s “Geology of England and Wales.”? Being well acquainted with the Sunderland district, I determined to take the first opportunity of ooking for the rock, and, such an opportunity having occurred during the past summer, I now give the results of my work. So far as I am aware, there are only three references to this variety. 1 Judd, Memoirs of Geol. Survey, Geology of Rutland, pp. 117-188; Hudleston, ‘Proc. Geol. Assoc. vol. xi. p. 104. * Cole and Jennings, Q.J.G.S. vol. xlv. (1889) p. 426. 3 p. 219. 118 G. W. Card—Flexibility of Rocks. In his great memoir on the Magnesian Limestone, Prof. Sedgwick has the following passage :'—‘“The very thin lamine of the latter (i.e. the earthy, finely-bedded limestone) variety, which occur in abundance near Marsden Rocks, are often slightly flexible, and very fine specimens of flexible magnesian limestone with thicker lamina occur in a bed near the middle of the cliff.” The second reference is that mentioned above, in ‘The Geology of England and Wales,” and is to the same effect; while the third occurs in Bauerman’s Mineralogy” under the heading “ Dolomite,” where it is stated that the stone is flexible when freshly quarried, implying that the property is transient.® It would thus seem as if the Marsden locality were the only one from which flexible limestone has been described, but I was fortunate enough to procure beautiful specimens on the coast a little south of Sunderland, and therefore several miles from Marsden, which lies about two miles south of the mouth of the Tyne. For some distance south of the Hendon dock the cliffs consist of Glacial Drift; passing this, and following the cliffs, now composed of Magnesian Limestone, shortly before coming to the first point a position is reached where considerable falls of stone occasionally occur. It was from a recent fall that the specimens to be described were procured ; the spot being about 1000 yards south of the Blue House Inn. From a similar fall in Marsden Bay, on the south side near the Rocks, I also obtained specimens, but these were inferior to those from Sunderland, and will not be again referred to. The cliffs here are mainly composed of a laminated magnesian limestone ; that from above being earthy, friable, and comparatively unaltered, while in the lower portion of the cliff the stone, while still tending to split along the bedding-planes, which are very clearly marked, has been compacted by the re-crystallization of the whole. It is from the upper part that the flexible variety comes. Owing to the strike corresponding approximately with the trend of the coast, the outcrop in the cliff is horizontal. Bedding is very perfect, and many perfectly level slabs, of several square feet in area, have been brought down by the fall. It was from these slabs that my specimens were procured; and I see no reason why, with care, very large specimens showing flexibility might not be obtained. The colour of the stone is light yellow, the surfaces of the lamine: are coated with a yellow powder which soils the fingers, lamination is sometimes very perfect (‘75 mm.), the whole being uniformly very fine in grain, and requiring careful handling because of its. softness and friability. In general appearance it is, indeed, not unlike a fine-grained sandstone, and appears to have resulted chemically from deposition in successive layers. An interesting feature is the occurrence of many minute nests of 1 Trans. Geol. Soc. ser. ii. vol. iii. 1835, p. 87. 2 Text-book of Descriptive Mineralogy, H. Bauerman, p. 353. 3 However it may be at Marsden, this is certainly not the case at Sunderland. After having been kept in a dry place for several months, the specimens from the latter locality have undergone no loss of flexibility whatever. 4 Sedgwick, op. cit. p. “86. G. W. Card—Flexibility of Rocks. 119. calcite; mostly of about three or four millimetres diameter. These appear of a brown colour when very small, but when larger this appearance is seen to be due to a coating of ferruginous matter which lines the cavity in which the crystals occur. In one case a perfect geode of about 1 c.m. in diameter and lined first with a ferruginous coating and then with calcite crystals occurred. The position of such a nest would he indicated externally only by a slight elevation on the surfaces of the lamina. This was especially the case with the geode mentioned above; its position was clearly indicated by a slight bulging of either side of the lamina in which it occurred, the protuberance being flattened and marked with con- centric rings. It would seem as if such a geode might mark an incipient stage in the formation of some of the concretionary structures of which this series affords so many beautiful examples. A specimen in my own collection may well have originated in this way; it is flattened on one side, irregularly dome-shaped on the other, with a cavity open on the flat side, and extending into the interior of the dome. ‘There are no cracks or any other com- munication across the planes of bedding, and the nests occur quite isolated—not in strings. It is therefore evident that they have originated in the bed itself.1 These structures will again be referred to when the case of the flexibility is dealt with. An analysis made under the superintendence of my friend Mr. W.. Tate, A.R.C.S., gave the following results :— COSTER ces s cae) cba cones 4ORAZG CAO MR tec. ties! ceey,) CHG OORT 44 WIGO) gost “dee Re eReeMnsce . coo oom. /ZAIGIG®) SO ee as \, Ses coe SCR eres -518 SIO Spec Cites, Ueki enki!” Sactampeynretan L028 No tall Paes IO sg OD Notwithstanding the friability of the stone, sections can readily be prepared transverse to the bedding planes. Mr. F. Chapman, who prepared mine, tells me he had no difficulty after soaking the specimens in Canada-basalm. A low magnifying power reveals a large number of irregularly-shaped empty spaces, in the main arranged linearly in directions parallel to the bedding, but also occurring promiscuously through the section.? With a 4-inch objective the section is resolved into an aggregate of grains of feebly-polarizing dolomite, the larger grains averaging about ‘Ol mm. in diameter, with a very few minute grains of quartz, and here and there of blue- and of brown-coloured minerals. With a 4-inch, and still better with an 4-inch, the grains are seen to be irregular in outline; the larger grains (sometimes attaining a diameter of -02 mm.) frequently appear to be intergrown in such a way that a convexity of one fits into a convexity of another, or a pro- jection into a depression. Very rarely a minute piece of mica occurs. Having described the general appearance of the stone, the nature of its flexibility remains to be dealt with. In every case I find 1 Sedgwick, op. cit. 2 See Woodcut, Fig. A., p. 123, infra. 120 G. W. Card—Flexibility of Rocks. that the flexibility diminishes with the thickness of the lamina; pieces of 5mm. or more in thickness exhibit the peculiarity in only a slight degree, while the laminz of 1 mm. or less are very flexible indeed. Here, however, I may mention that the behaviour of specimens obtained from the same slab varied very much. A speci- men of average flexibility and of 1mm. or less in thickness feels almost leathery, bending over in all directions when held by one side or supported in the middle. A strip—trimmed down with a knife—5°3 cm. long, 25cm. wide, and 1:5 mm. thick, supported at one end so that 5-3cem. projected, gave the following results. By its own weight (44 grains) the strip bent until the free end was 1‘6cm. lower than the point of support. Now suspending it vertically it straightened itself in a few seconds and, on being turned over and once more supported at the same end, bent as before, but to not quite the same amount. By pressing the free end with the finger it was brought 38-lcm. below the horizontal, when the strip broke off close to the point of support. Experimenting with another piece; after a little pressure had been applied to the free end, it straightened when suspended, but, when once more supported at one end in the same position, it assumed by its own weight a position approximating to that which it had been before bent by pressure. With regard to the cause of flexibility I can only offer the follow- ing suggestions. In the first place, room for internal movement is provided for by the abundance of empty spaces, and in the second, the structure revealed by high magnifying powers suggests the possi- bility that many of the grains are interlocked in such a way as to permit of a certain amount of movement upon one another.’ Such an explanation would not be incompatible with the coherency of the rock ; as a matter of fact the coherency is very slight, the material crumbling to pieces with great readiness: moreover, many of the grains are to be bound together in such a way that their margins cannot be made out. Owing to the small size of the grains, it is unpossible to demonstrate whether they have such power of move- ment or not. The empty spaces have, no doubt, resulted from the removal of carbonate of lime by percolating water. The bedding-planes have afforded the easiest passage, and it is along these planes that the cavities for the most part occur. It would appear as if much of the material so dissolved had been redeposited as calcite in the geodes. 2. The Cause of Flexibility in ‘ Itacolumite.”—-Before considering this question, it is very necessary to arrive at some sort of an under- standing as to what the rock which has been known as ‘‘Itacolumite,” “ Flexible-Sandstone,” “ Flexible-Quartz,” and a variety of other names,” really is. Towards the close of the last century a peculiar siliceous rock was noticed in Brazil. Attention was directed to it principally because it often constituted the matrix in which diamonds occurred, but also because thin pieces of it were sometimes found to be flexible. Owing to its occurrence in the mountains of Itacolumi, 1 See Woodcut, Fig. B., p. 123, infra. ° * Third Report on the Geognostic Survey of South Carolina, 1848, p. 85, et. seq. GEOL. MAG. 1892. Dec. Ill; Vor. IX. Pl. IV. LW. Wolk k “nt ad wal Fig. 1.—Section of Hirnant Limestone x 20. The grains are made up of four layers—(1) Central nucleus of calcite. (2) Carbon. (3) “Chalcedonic”’ silica. (4) Outer bands of dusty material and carbon. (3) and (4) are sometimes repeated, Fic. 2.—Section of Hirnant Limestone x 100. To illustrate Mr. L. W. Fulcher’s paper on the Composition and Structure of the Hirnant Limestone. (p. 114.) BPS cmd pee S G. W. Oard—Flexibility of Rocks. 121 éarly writers referred to it as “Itacolumite”’; a list of such references will be found in Zirkel’s “ Lehrbuch der Petrographie” (Bd. ii. p. 484). Subsequently similar rocks, also occasionally exhibiting flexibility, were discovered in other parts of the world, more especially in the Southern States of North America, and, at.a later date, in India. - The term ‘“‘Itacolumite” has been applied to the rock itself by most writers; Tuomey, who restricts it to the flexible variety, is an exception. ‘The accounts given of the rock are fairly consistent, all agreeing in describing it as a stratified and granular variety of quartzite; frequently, especially in the case of the Brazilian and Carolina specimens, a good deal of mica occurs upon the bedding- planes. Coming now to the terms applied to the flexible portion, “Sand- stone” may be objected to on the ground that flexibility is at present unknown in unaltered siliceous sedimentary rocks, but Prof. Derby has pointed out! that there is no reason why it should not occur in sandstone. : Almost without exception the flexibility sometimes exhibited by *Ttacolumite” has been ascribed to the quartz grains being en- veloped by a flexible mineral variously referred to as mica, sericite, tale, or chlorite. As exceptions I may mention Klaproth and Prof. Haughton, both quoted? by Mr. Oldham, and von Hausmann, referr | to by Zirkel.? Leibner, in the report on South Carolina bef quoted, devotes a good deal of attention to the cause of flexibility, and considers that four conditions must be fulfilled, viz. : 1. “ Fineness of grain.” - 2. “Sufficient admixture of mica or tale.” _ 0. “Delicately laminated structure.” 4. “Certain degree of compactness in the constituents of each lamina.” In this way he explains the very local occurrence of portions, since all the conditions must be fulfilled simultaneously. It would seem as if the flexible-mineral theory was at first nothing but a suggestion, but Leibner definitely gives his assent to it. Leaving the older views—which are still given in most text-books—two im- portant papers have been lately published by Mr. Oldham,‘ and by Prof. O. Miigge respectively, which propound quite different views as to the cause of flexibility. To these may be added a third by Prof. Derby ® on the mode of occurrence of the Brazilian specimens. Prof. Derby’s paper deals with the very local occurrence of flexible portions in the Itacolumite Series; the same mass of rock may contain ‘‘massive and schistose, compact and friable, non-flexible 1 Am, Journ. Sci. xxviii. 1884, p. 205. 2 Rec, Geol. Surv. India, vol. xxii. pt. 1, 1889, p. 53. > Lehrbuch der Petrographie, 1886, Bd. 11, p. 482. 4 On Flexible Sandstone or Itacolumite, R. D. Oldham, A.R.S.M., Records Geol. Sury. India, vol. xxii. pr. 1, 1889. ° Ueber “ Gelenksandstein’’ aus der Umgegend von Delhi O. Miigge, Neuen Jahrbuch, Bd. i. 1887. i On the Flexibility of Itacolumite, Orville A. Derby, Am. Journ. Sci. vol. xxviii. 1884. ne 122 G. W. Card—Flexibility of Rocks. and flexible portions, within a distance of a few centimetres, and in exactly the same relative position in the bed.” The author’s con- clusion is that flexibility is a phase of weathering. 'Tuomey came to the same conclusion with regard to the South Carolina stone, but Leibner differed from him. Miigge describes the Delhi stone. There is a very little mus- covite, but so small a quantity that it cannot possibly give rise to the flexibility. A small amount of clayey matter is present, not surrounding the quartz grains, but in patches which are not sufficient to fill the interspaces; the quartz is therefore much clearer than in ordinary sandstones, and the grains are in direct contact with one another; moreover, the grains have a very irregular out- line (comparable to Babel-quartz), being very different in appearance from those of common sandstone. When examined in thin sections. by means of polarized light, the quartz grains are seen to be hooked together. This interlocking accounts for the grains holding together, and at the same time allows of a certain amount of movement taking place, space for movement being afforded by the decomposition of the clayey patches. In this way the author thinks the flexibility can be explained. Dealing briefly with the Brazilian stone, he shows that the quartzes present an appearance almost identical with the Indian; there is very little clayey material, so that a section is almost as clear as water; while muscovite occurs only in small quantity, and in flakes much too short to envelop the quartz-grains. It is suggested that the structure of these rocks originated by a partial removal of the cementing material; the quartz-grains then resumed their growth, but the supply of material failed before the interspaces left on the removal of the clayey matter were completely filled. Mr. Oldham, also dealing with the Delhi specimens, arrived independently at the same results. In India, as in Brazil and in South Carolina, flexibility is correlated with decomposition. Examined under the microscope by reflected light a number of quartz- ageregates, separated by vacant spaces which appear to be ramifying fissures, are seen. These aggregates can be moved by a needle without displacement, the movement being the result of the grains being hinged together, a projection from one fitting into a depression in another. He also notices the occasional presence of felspathic paste, which, by its relative abundance and mode of distribution, determines the degree of flexibility that will be possible on its de- composition and removal. Having regard to the subject of this paper, one of the specimens described by Mr. Oldham is of special interest. It is a variety from Charli, south of the Pemganga River (Berar). “An ordinary soft sandstone of rounded grains of quartz, with a little felspar, held together by a cement of carbonate of lime, which forms 35:9 per cent. of the whole mass.' Here there is no comparatively soluble material whose removal leaves the rest of the rock as a mass of irregular aggregates interlocking with each other, for on removal of the cement. by solution, the rock falls into sand. 1 The italics are mine. G. W. Card—Flewibility of Rocks. 123. But if the fractured surface of the rock is examined, an abundance of sheeny patches point to a crystallization of the cementing matrix, and these crystals offer a number of planes in various directions along which solution proceeds with greater rapidity than elsewhere ; and as a result the rock becomes divided into irregular interlocking aggregates of sand and calcite.”? The mode of interlocking in both varieties is illustrated by drawings. Section of Flexible Limestone from the coast, a little south of Sunderland (see ante, pp. 118-120). Del. Geo. W. Card, Fic. A.—Flexible Limestone cut transverse to bedding, and showing empty spaces. x 10. (p. 119.) Del. Gece W. Carde Fig, B.—Flexible Limestone highly magnified, x about 400. (p. 120.) An examination of a section of the North Carolina material in the collection of this institution gives similar results: the quartzes are very clear, have very irregular outlines, and are generally in direct contact; there are a number of cavities, and apparently an articulation of the grains, while mica is present in very small quantity only. 3. It will now be useful to briefly compare these ‘“ sandstones ”’ with the Durham Limestones. In thin lamine the flexibility is very similar in degree; Leibner found that a strip of Carolina Sandstone, very similar in dimensions to the strip of limestone used by myself, 1p. 54. 124 G. W. Card—Flexibility of Rocks. but a little thicker (45-inch), bent under pressure through a vertical distance equal to somewhat less than half the length of the strip; the limestone gave slightly higher results, but was somewhat thinner (1:5 mm.). In slabs of greater thickness, however, the superior flexibility of the Itacolumite is very marked; thus Mr. Oldham found a piece 17 inches long by ‘75 inch thick bent through 7 inches of its own weight, while in slabs of limestone of 5 mm. thickness flexibility becomes very slight. They agree also in a decrease of flexibility accompanying increase of thickness. In both cases the occurrence of flexible portions is very local; this has already been referred to, but it may be mentioned further that fine-grained, bedded, non- flexible limestones occur in the neighbourhood, and it would be interesting to know whether these non-flexible beds possess the internal structure described above. It is, however, in internal structure that the resemblance is most marked, both exhibiting a number of vacant spaces accompanied by an interlocking of the constituent crystalline grains. Flexibility would thus seem to arise from similar causes; we have room for movement afforded by empty spaces, the result of solution of carbonates in the one, and of the decomposition and removal of patches of felspar in the other; while the direct cause of bending is the interlocking of the grains. It is well known that a distinct sound is heard when flexible sand- stone is bent; the limestone does not give rise to any sound that is audible, but, from the inferior hardness of calcite, as compared with quartz, this is no more than might be expected. Lastly, there is the occurrence of the calcareous rock at Charli. This may, indeed, be regarded as a connecting link between flexible Itacolumite on the one hand and flexible limestone on the other. It is not only that it contains a certain proportion of carbonate of lime; that might be quite a matter of detail; but from the passage quoted above it would seem that the calcite plays an important part, forming interlocking aggregates, and affording the space necessary for movement by its solution. Moreover it is described as a common sandstone, the grains of quartz being somewhat rounded; this would seem to emphasize the presence of the calcite, as it is not clear what part such quartz can take in effecting movement. In conclusion, now that a number of rocks are known to exhibit the property of bending without fracture, in each case the phenomenon being no more than a natural concomitant of certain phases of alteration, the undesirability of giving distinctive names to the different varieties will be at once apparent. Indeed, there seems no reason why many other varieties should not also occur, although, from the nature of the conditions to be fulfilled, we cannot expect to find flexible beds in considerable quantity. ' Ihave already acknowledged my indebtedness to Prof. Judd, and it only remains to state that this work has been carried out in the Geological Laboratory of the Royal College of Science. Reviews—Prof. F. W. Hutton—On the Dinornithide,~ 125 dS.) DEAE AG aa WA (Se J.— CLASSIFICATION OF THE Moas (DinorniITHIDH) or New Zeaanp. E have received from Prof. F. W. Hutton, F.G.S., an abstract of a paper read by him at the Canterbury Philosophical Institute on Oct. 1st, 1891, in which the classification of the extinct flightless birds of New Zealand is discussed. Mr. Lydekker having recently treated the subject at length in the British Museum Catalogue of Fossil Birds, from an examination of the material now in the Museums of London, Capt. Hutton’s work is especially opportune ; and it is to be hoped that before the printing of this memoir, based upon the unrivalled specimens in the New Zealand Museums, the author will have the opportunity of incorporating the results of his British co-labourer. Both Mr. Lydekker and Capt. Hutton recog- nize several new specific types, and it is especially desirable that the forms just determined by Mr. Lydekker should not be re-named in the forthcoming work. Captain Hutton regards the known Dinornithide as divisible into seven genera and twenty-six species. ‘‘The genera are founded chiefly on the skulls, but also have characters derived from the sternum, pelvis, and the robustness of the leg-bones. The species are distinguished almost entirely by size, but sometimes characters derived from the skull can be given. In many cases the species run one into the other, and the lines between them are drawn so as to give about an equal range in variation to each species.” The generic diagnoses are as follows :— Genus Dinornis. Skull depressed, the lambdoidal ridge flattened and the parietals hardly rising above it; the breadth at the squamosals greater than the length from the supra-occipital to the nasals. Beak rather longer than the head, depressed and obtuse at the tip; the lower jaw much curved. A scapulo-coracoid without any glenoid cavity. Including sub-genus Dinornis (‘‘ Top of head flattened’) with species altws, maximus, giganteus, robustus, imgens, and four new species; also sub-genus Zylopteryx (‘‘ Top of head. elevated ’’) with species gracilis, struthioides, and one new form. Genus Panapreryx. Skull depressed; the breadth of the squamosals less than the length from the supra-occipital to the nasals. Beak about as long as the head, more compressed than in Dinornis; the lower jaw nearly straight. A scapulo-coracoid with a glenoid cavity and probably a wing. Including BP. dromioides and one new species. Genus ANoMALOPTERYX. Skull very convex, the maxillo-jugals curved. Beak short, slightly compressed and rounded at the top ; the lower jaw strong and nearly straight. A small scapulo-coracoid. Including 4. didiformis (=A. parvus), and one new species. Genus Ceza. Skull convex. Beak short, slightly compressed and rounded at the tip ; the lower jaw nearly straight and rather slighter than in Anomalopteryx. No scapulo-coracoid, Including ©. geranoides and C. curtus (= Dinornis Oweni, Haast). Genus Mzsorreryx. Skull convex, angled behind. Beak shorter than the head, moderately curved, much compressed and pointed at the tip; the lower jaw slender. No scapulo-coracoid. Including YW. didinus (=Dinornis Huttoni). Genus Syornis. Skull convex, rounded behind. Beak shorter than the head, moderately curved, much compressed and pointed at the tip; lower jaw strong. No scapulo-coracoid. Including S. rheides, crassus, and casuarinus. Genus Evryarreryx. Skull moderately convex. Beak very short and stout, slightly compressed and rounded at the tip ; the lower jaw moderately curved. No scapulo-coracoid. Including Z. elephantopus and E. gravis, with twe new species. ; : 126 Reviews—Dr. C. Barrois—Faune du Grés Armoricain. In a popular summary of his results, contributed to a local news- paper, Captain Hutton makes some interesting comments on the remarkable diversity thus recognized among the extinct Struthious birds of New Zealand. He considers that a plausible explanation of the facts may be deduced from the known distribution of the existing Cassowary. One species inhabits Australia at the present day, and eight others occur on the islands from New Britain to Ceram. The eight species inhabit five different islands, “and if this region of the earth were to be elevated, and the islands joined together, these eight species would mingle. If the region were to sink once more all of them would be driven to the highest land, and might be crowded into one small island. Now, we know from geology, that New Zealand has gone through a series of changes in level, similar to those just mentioned. In the Miocene period it consisted of a cluster of several islands, which were elevated and united in the older Pliocene, and ultimately divided into the two islands we have now in the newer Pliocene. If the ancestors of the Moas inhabited New Zealand during the EHocene period, they must have been separated on these islands during the whole of the Miocene, and mingled together again in the Pliocene. In this way— fe. by isolation—probably the genera originated, but the species appear to be due to variations without isolation. As is the case with most common animals, the Moas varied greatly, and, there being no carnivorous mammals to hold them in check, while vegetable food was abundant, natural selection did not come into play, and the intermediate forms were not strictly eliminated. Under such favour- able circumstances the conditions of life were easy, and the birds got larger and fatter, more sluggish and more stupid. The oldest known Moa is one of the smallest, and it is the smaller species which are found in both islands; from en we may infer that they were the only ones in existence when the two islands were united, and that the Moas since then increased in size. But the very large Moas were always comparatively rare. The commonest kinds in the North Island were only from two and a half to four feet high, while those of the South Island were mostly from four to six feet in height. The giant forms, going up twelve and thirteen feet, were seldom seen.” Such speculations are an incentive to further research, and both zoologists and geologists will anxiously await the appearance of a memoir that will evidently touch problems of very wide import. IJ.—Mémorre sur 1a Faune pu Gris Armortcarn, par CHARLES Barrors. Annales de la Société Géologique du Nord, Tome xix. pp. 164-2387, Pls. 1L-V.. April, 1891. M\HE rocks in Brittany known as the ‘grés armoricain,’ have a special interest from the fact that they are pretty well the lowest in France from which specifically determinable fossils have been obtained. M. Lebesconte has partly described and figured from them, fragments of Trilobites belonging to the genera Ogygia and Homalonotus and some years since the late Dr. 'T. Davidson? 1 Grou. Mac. Vol. VII. (1880), p. 342, Pl. X. Reviews—Dr. C. Barrois—Faune du Grés Armoricain. 127 figured and described in the pages of the Gronocican Magazine several species of Lingula from the same horizon. A few other fossils, Mollusca principally, were also known in these beds; but owing to the fact that these forms were in poor preservation, existing only as moulds, no systematic attempt had been made to determine them. In spite of this obstacle Dr. Barrois has suc- ceeded in working out this group, and has described and figured in this memoir no fewer that 29 species of Lamellibranchs, 13 of which are new forms. The principal genera represented are Actinodonta, Phillips; Lyrodesma, Conrad; Redonia, Rouault ; Cteno- donta, Salter ; Nuculites, Conrad ; Nuculana, Link ; Cyrtodonta, Billings ; Modiolopsis, Hall, and Hippomya, Salter. The Gasteropoda are included in Paleacmea, Hall, and Bucania, Hall, and there is a single species of Conularia. ‘There are also some Crustacea referred to Myocaris, Salter; Ceratiocaris, M‘Coy, and Trigonocarys, gen. nov. Specimens of the peculiar fossil Discophyllum (Actinophyllum) plicatum, Phillips, sp., also occur in the grés armoricain, and they are ranked by the author as calcareous sponges, similar to those of the family Pharetrones, Zittel; but after a careful examination of Phillips’ types, we fail to recognize any characters which can ally them to sponges. Including forms previously known, Dr. Barrois now enumerates a list of 45 species of invertebrate fossils from the ‘ grés armoricain’ in the departments of Ille-et-Vilaine and Loire Inférieure. Taking into account the occurrence of the genera Ogygia and Homalonotus, and of the Lamellibranchiata now described, the author is fully justified in concluding that the fauna cannot be Primordial, but he considers that it is intermediate between this latter and the Llandeilo fauna. There is a very significant similarity between many of the Lamellibranch genera of the ‘grés armoricain’ and those occurring in the Trenton and Chazy groups of Canada and the United States, thus indicating a nearer relation to these rocks than to the underlying Calciferous formation in these countries. Again, when compared with British strata, the molluscan fauna of the ‘orés armoricain,’ approaches nearer to that of the base of the Arenig than to that of the older Tremadoc. If this supposition is correct, the fauna of the ‘grés armoricain’ cannot correspond with the earliest period of the second Silurian fauna, and consequently neither a Tremadoc nor a Primordial fauna has yet been discovered in Brittany. Notwithstanding the identity of the Bilobites and Scolites in the ‘grés armoricain’ with those of the Lingula Flags, the author states that these rocks cannot be compared together in point of age. Touching the classification of the schists, conglomerates, phyllades, ete., which in Brittany occur beneath the ‘grés armoricain,’ con- siderable differences of opinion exist among French geologists, but Dr. Barrois adopts that of Dufrenoy, and considers the “Btage of Gourin to correspond with the horizon of the Primordial fauna, and the phyllades of St. L6 with the Longmyndian of Callaway. G. J. H. 128 Reviews—Dr. G. Holn—On Lituites. TJJ.—Om mynnincen nos Liruirrs, Breyn. Af Geruarp Hou, Geol. Féren. Forhandl. No. 140, Bd. 18, Hift 7, 1891. On THE APERTURE IN THE GENUS Liruirrs, Bruyn. By GerHarD Horm. Transactions of the Geological Society in Stockholm, Vol. 18, pp. 736-780, Pls. 10-12. HE terminal aperture of the shell in the Lower Silurian Cepha- lopod genus Lituites, Breyn, is so seldom preserved intact, that different views have been maintained respecting its true form. Quenstedt stated that it was furnished on the ventral side with two projecting straight lobes. Noetling showed later that there were four of these lobes, one pair on the ventral and the other on the dorsal side; but in the lately published Brit. Mus. Cat. of the Cephalopoda, A. H. Foord adopts the statements and figures of Lossen that not more than two incurved lobes are present, and considers Noetling’s observations erroneous. Dr. Holm has obtained some very perfect individuals both of Lituites lituus, Montf., and L. tenuicaulis, Rem., which show clearly that in the aperture of these species, there is, in addition to the two pairs of lobes described by Noetling, another small unpaired lobe on the dorsal side, so that, when complete, there are five lobes. This number seems to prevail in the majority of the species, but the author describes a new form, LI. discors, in which only three lobes are present, and another, L. precurrens, which may possibly only have possessed two lobes, and on account of its strongly marked conical form would come into the so-called genus Ancistroceras. A new species of Cyclolituites, Remelé, is also described, which definitely shows that the forms placed in this genus are not merely the loose spirals of species of Lituites, but distinct members of the Lituitidee family, from which probably the typical Lituites have been developed. Gusset ITV.—Tue Fossin Insects or NortaH AMERICA, wiTH NOTES ON somE European Sprcies. By Samurn H. Scupper. Vol. I. The Pretertiary Insects, with Thirty-five Plates. 4to. pp. 456. Vol. II. The Tertiary Insects of North America, 4to. pp. 734, with Twenty-eight Plates.! New York: Macmillan & Co. (1891). HE Essays contained in the first volume of the present work have (the author tells us) no logical connection. They were written and printed at different times during the past twenty-five years, and are here issued exactly as first priated. But they cover nearly the whole of a single limited field in paleontology, of which the author may be said to be almost the sole exponent in America. Mr. Scudder’s name is now as familiar to European Palzontologists as it is to those of America, and, so long ago as 1868, he communi- cated to the GronocicaL Magazine, at the request of Sir Charles Lyell, a most valuable digest “On the Fossil Insects of North America,” so far as then known (Grou. Mag. Vol. V. pp. 172-177, and pp. 216-222). 1 For a Review of yol. ii., see Grou. Mac. 1891, Decade III, Vol. VIII. pp. 280-282. Reviews—Dr. S. H. Scudder—On Fossil Insects. 129- 1. The volume opens with an essay on “the first discovered traces ° of Fossil Neuropterous Insects in North America,” and was read before the Boston Society of Natural History, in January, 1865, (published in 1866 with one plate). 2. The second is on “the Carboniferous Myriapods preserved in the Sigillarian stumps of Nova Scotia.” 3. Next follows a short essay on ‘the early types of Insects; or the origin and sequence of Insect-life in Paleozoic Times.” 4. The fourth paper on “ Palaeozoic Cockroaches,” with a revision of the species of both worlds, and an essay on their classification (illustrated by five quarto plates), is one of Mr. Scudder’s most important contributions. At first glance at the plates it would appear as if the materials at the author’s disposal were better preserved and more abundant than usually falls to the lot of any single student of fossil insects; but the figures occupying the first three plates out of the five illustrating this paper, are copies from the plates of Germar, Goldenberg, Giebel, Heer, etc., of all the then known European forms (1879), the last two only being drawn from original American specimens.’ It is doubtless a very great convenience to have the whole of the forty-nine European forms redrawn and brought together thus for comparison with the eighteen American species, but the complete - revision of all the European species, from the figures and descriptions alone, must be a somewhat hazardous task without seeing the original specimens as well. However, we may be very thankful to Mr. Scudder for his scheme of classification, nor are we likely to better it, for some time to come. : The specimens figured are all detached wings, and the proposed arrangement is based solely upon their neuration. : 5. The next Memoir is on “The Devonian Insects of New Brunswick” (illustrated by Plate 7), first described and figured (by Scudder) in a paper by Sir William Dawson in the Grou. Mae. 1867 (Vol. IV. pp. 385-388, Pl. XVII. Figs. 1-5). 6. The sixth Memoir is on the “ Archipolypoda, a subordinal type of spined Myriapods from the Carboniferous formation” (with four plates). This Essay is particularly interesting to English paleon- tologists on account of the discovery of similar forms of spined Myriapods in the English Coal-measures.* 7. The next paper is on “The Carboniferous Hexapod Insects of Great Britain,” and describes and figures (a) Brodia priscotincia, Scudder, from a Clay Ironstone nodule of the Coal-measures, Tipton, Staffordshire; (originally described and figured (as a woodcut) in Guot. Mac. Dee. II. Vol. VIII. p. 293, 1881). (b) Archeoptilus ingens, Scudder, a fragment of the base of the wing of a large Neuropterous insect, from the Coal-measures near Chesterfield, Derbyshire, and ' Mem. Soc. Nat. Hist. Boston, 4to. vol. iii. pp. 23-134, pls. 2-6. Originally published Mem. Boston Soc. Nat. Hist. vol. iii. No. v. pp. 148-182, pls. xxiii. 1882. 3 See H. Woodward, ‘‘On some Spined Myriapods from the Carboniferous Series of England,” Grou. Mac. Dec. III. Vol. IV. Pl. I. pp. 1-10, 1887. DECADE I1I.—VOL, 1X.—NO. II. 9 130 Reviews—Dr. S. H. Scudder—On Fossil Insects. is like the preceding example in the collection of the Rev. P. B. Brodie (Grou. Maa. 1881, p. 295). 8. This paper is on “'T'wo New and Diverse Types of Carbon- iferous Myriapods ;”’ namely Trichiulus villosus, T. nodulosus, and T. ammonitiformis (no longer a myriapod). Palgzocampa anthrax from the irenstone nodules of Mazon Creek, Morris county, Illinois (illustrated by two plates). 9. The ninth paper is on “the species of Mylacris, a Carboniferous genus of Cockroaches,” of which Mr. Scudder describes six species founded on six detached wings, which are also figured. They are from Mazon Creek, Pittston, and Cannelton, Pennsylvania. 10. This essay is devoted to ‘‘The Earliest Winged Insects of | America: a re-examination of the Devonian Insects of New Bruns- wick, in the light of criticisms and of new studies of other Palaeozoic types.” Surely these remains are too fragmentary and obscure to devote more time to their re-examination or lengthy discussion. It would be more profitable to look for better materials to study. 11. On “ Paleodictyoptera: or the affinities and classification of Paleozoic Hexapoda.” In this paper the author describes and figures (in four quarto plates) anumber of new Carboniferous winged insects principally from Mazon Creek, Illinois. One form, Archegogryllus priscus, is considered to belong to the Orthopteroid-Paleeodictyoptera; but the twenty-three other forms named and figured are referred to the Neuropteroid section. The neuration of many of these forms, pre- served in ironstone nodules, is obscure and very difficult indeed to trace with accuracy, and therefore their determination must be to a considerable extent tentative. 12. “ Winged Insects from a Paleontological point of view, or the Geological History of Insects.” In this paper the author con- tends that throughout Paleozoic times insects continued as a general- ized form of Heterometabola which he calls Paleeodictyoptera, and which had the front wings, as well as the hind wings, membranous. On the advent of Mesozoic times a great differentiation took place, aud before its middle, all of the orders, both of Heterometabola and Metabola, were fully developed in all their essential features as they exist to-day, the more highly-organized Metabola gradually becoming the prevailing type (p. 322). 13. The thirteenth paper is on ‘the oldest-known Insect-larva (Mormolucoides articulatus) from the Connecticut River Rocks” (Triassic).? (See pl. 19, and woodcut, p. 328.) 14. This is ‘‘A Review of Mesozoic Cockroaches,” dealing with the Secondary forms of Blattariz after the manner in which the Paleozoic forms were dealt with in Essay No. 4, only in this case all the species figured and described are British or European, but almost all are from the Lias or the Purbecks of England. Many of 1 Originally printed in Memoirs of the Boston Society of Natural History, vol. iii. No. ix. 1884. * Published in the Geox. Mac. Vol. V. 1868, p. 218, without a figure. Reviews—Dr. S. H. Scudder—On Fossil Insects. 131 them are based on fragments from the Purbeck, which Westwood named but did not describe ; or figured, but did not name; or, which Brodie found but did not name or describe. These wings are for the most part fragmentary and must have required good courage to found species upon them. Surely there is something wrong about Pierinoblattina penna! (pl. 22, fig. 14). Is it an insect-wing at all ? 15. Is on some “New Types of Cockroaches from the Carboni- ferous Deposits of the United States.” These forms, which fill two quarto plates, are considerably better-preserved remains than any of the others previously figured; fig. 5, pl. 23, Archimylacris pauct- nervis, and fig. 3, pl. 24, Oryctoblattina occidua, being very remarkable and aberrant forms. ‘These cockroaches are from the Richmond, Ohio, coal-field, and from Mazon Creek, Illinois. 16. This paper is devoted to more “‘ New Carboniferous Myriapoda from Illinois.” The greater number of specimens are referred to the genus Huphoberia and to eight species. The other to Acantherpestes, Archiulus, Xylobius, Ilyodes, Latzelia, Palenarthrus and Hilecticus. These are mostly from Mazon Creek, Illinois, and are very beautifully drawn on six quarto plates illustrated by fifty-seven figures. 17. Is devoted to “Illustrations of the Carboniferous Arachnida -of North America of the orders Anthracomarti and Pedipalpi.” The Anthracomarti is said to be the only extinct order of Arach- nida, and was established by Karsch for some interesting Carbon- iferous forms allied to the Phrynidz and Phalangide, although very distinct from either of them. To this group belong forms like Hophrynus Prestvici, H. W. (1871), from the Coal-measures, Coalbrook-dale;. Architarbus sub- ovalis, H. W. (1872), Coal-measures, Lancashire; numerous allied forms from the Permo-Carboniferous of Bohemia. Another form, mamed by Woodward as Brachypyge carbonis (Gruot. Mac. 1878, Pl. XI. p. 434), from the Coal-measures of Belgium, has since been removed (at the suggestion of Mr. Scudder) to the Anthracomarti, near to Hophrynus (see Guot. Mac. 1887, p. 49, footnote). Scudder’s genus Geraphrynus (pl. 32, figs. 1,9, 10) and his Anthracomartus (pl. 31, figs. 7-10) must be very near to Hophrynus. Of the order Pedipalpi, Scudder’s Geralinura carbonaria is also represented in the Coal of Bohemia by several closely allied species. 18. The last paper is on ‘The Insects of the Triassic beds at Fairplay, Colorado.” These include thirteen species of Paleo- blattariz and Blattarie and three species of Hemiptera. The descriptions of these cockroaches are based on wings, but two or three species are founded on the pronotum alone. The volume concludes with a Biographical note on American Literature, treating of the older fossil Insects ; followed by an Index and thirty-four excellent plates. Most of the papers are undated and need references, but they have, as a rule, been all published, in their present form, at various times, in the Memoirs of the Boston Society of Natural History. Vol. II., which treats of the Tertiary Insects of North America, is -a reprint from vol. xiii. of the Report of the United States Geological 182 Reviews—H. P. Woodward— Western Australia. Survey of the Territories (1890), which has already been noticed) (see Guou. Mac. 1891, p. 280). It includes the (Oligocene) Tertiary Insects of Florissant, South Colorado; those of the White River, West Colorado; Hastern Utah; and Wyoming. From Quesnel, British Columbia, Dr. G. M. Dawson has con- tributed numerous insects; and Dr. G. J. Hinde from Clay-beds, near Toronto, Canada, has added materials for 29 species. Alas! but few of those who, like the author, have devoted a life-time to paleeontology, ever have the good fortune to see, at the end of thirty years, their scattered brochures reprinted as a pair of» handsome quarto volumes! To many of us, the process would certainly not be feasible, commercially. To most it would hardly be a scientific gain. Compared with man’s best efforts after all, how much more enduring is the Epitaph which Nature has engraved upon the rocks to the Memory of the humble but long-lived Cockroach ! as ae ae ae Diving into our Hditorial waste-paper basket to-day we drew forth the following lines, grimy with soot, and inscribed :— ‘¢ Mancuester, Brit. Assoc. 1887. “¢ Tn times Carboniferous Scudder has shown, That the Cockroach was gaily then holding his own ; Do you think that in our case we too may last, If we stick to the Cook and the Kitchen as fast ?”’ (The second verse has, alas! been torn off, and is lost to science.) HWY. V.—GroLoGIcAL SURVEY oF WESTERN AUSTRALIA. ANNUAL GENERAL Report ror THE YEAR 1890. By Harry Pace Woopwarp, F.G.8., etc., Government Geologist. 8vo. pp. 53. (Perth, WEA S91.) HE last Report of the Government Geologist in Western Australia, was noticed in the GroLtoaicaL Macazine for October, 1890 (p. 468); and we then printed a Table of the Strata, which need not here be repeated, as no additions or alterations are necessary. In the present Report Mr. Harry P. Woodward gives a list of the fossils which, up to the present time, have been found in Western Australia. Some of these have been described in the GEoLocicaL MaGazine, as previously noticed. Among the Cambrian fossils, the record of Olenellus Forresti, associated with Salterella Hardmani, is of especial interest. Although this Olenellus was identified with a query by Mr. A. H. Foord, yet further knowledge of the genus, as lately published by Mr. C. D. Walcott, leaves no room to doubt that the query may be cancelled ; and indeed this element of doubt has been omitted from the Report. With regard to the Carboniferous and Devonian rocks it is remarked that ‘‘there seems to be an unbroken series of beds, the Lower. Carboniferous fauna gradually merging into the Devonian’”—a matter of considerable interest, as this is undoubtedly the case in Europe and North America. Reviews—F. Karrer—Austrian Building-stones. 133 In future lists of the fossils it would be convenient if the names ‘of authors were appended ; and the opportunity might be taken to correct some misprints in the names. The Report contains a general geographical and geological de- scription of the Victoria, Murchison, Gascoyne, Ashburton, Fortescue, Roebourne, and De Grey districts, with particular accounts of the mineral resources. ‘Alluvial gold was found by the Ashburton river in 1890; it has been derived from mineral veins in clay-slates. These slates are highly inclined, and on their upturned edges rest limestones and other strata of Devonian and Carboniferous ages. The Ashburton gold-field yielded about 15,000 ounces of gold in six months. At present only the rich patches in the shallow ground have been ‘worked ; the deep ground is as yet untouched, although in the large plains of the Ashburton river rich deposits are sure to be found, and it is likely to prove a permanent goldfield. Mr. Woodward remarks that “as the prospecting will be most ‘expensive work, no one will undertake it, unless he be granted a protection area, until the course of the leads has been ascertained.” The Pilbarra Goldfield is also reported to be “one of the most promising mineral areas in this Colony.” Particulars are likewise given of the progress of the Yilgarn and Kimberley Goldfields, of the Greenbushes Tinfield, and of the Collie River Coal-district. The Collie Coal is stated in the Report to be “‘a Mesozoic coal, of first class quality,” but from specimens subsequently submitted to Mr. Etheridge, he expresses his belief that it is “a good and true Paleozoic coal” (West Australian, Jan. 18, 1892). The question of age will not seriously affect the colonists, so long as the coal is good, and there is plenty of it. The extent has yet to be proved. V1I.—GuipE THRovGH THE CoLLEcTION OF BUILDING-MATERIALS IN THE ImpreRtau-RoyaLt Naturat- History Courr-Musrum oF Vienna. [Fiihrer durch die Baumaterial-Sammlung, ete. ] compiled by Ferrx Karrer; with a Preface by the Editor, Dr. Artstiprs Brezrna, Director of the Mineralogical Department. Small 8vo. 302 pages, with 40 Illustrations. Vienna, 1892. i the Introduction the rocks and minerals supplying materials for construction are enumerated and briefly described, and then referred to their respective geological ages and formations. ——__ GEOLOGICAL Soorrty or Lonpon. I.—AwnnvuaL GeneraL Meerine.— February 19th, 1892.— Sir Archibald Geikie, D.Sc., LL.D., F.R.S., President, in the Chair. The Secretaries read the Reports of the Council] and of the Library and Museum Committee for the year 1891. In the former the Council again congratulated the Fellows on the continued prosperity of the Society, and the perfectly satisfactory condition of its finances. The number of Fellows elected during the year was 63; of these 43 qualified before the end of 1891, together with 19 previously elected Fellows, thus making a total accession of 62 Fellows during the year 1891. As, however, from this number a deduction of 50 must be made for losses by death, resignation, and removal, and for new Fellows compounding, the actual increase in the number of Contributing Fellows amounts to 12. The total number of Fellows, Foreign Members, and Foreign Correspondents at the close of 1891 was 1418. The Balance-sheet for the year 1891 showed receipts to the amount of £2845 9s. 8d., and an expenditure of £2476 5s. 7d. Moreover, the sum of £516 2s. 3d. was expended in the purchase of stock, and the balance in favour of the Society at December 31st, 1891, amounted to £286 19s. 4d. The Council’s Report also referred to the severe losses sustained by the Society during the year in the deaths of several distinguished Fellows, to the death of the late House-Steward, to the editing of No. 185 of the Quarterly Journal by Prof. T. Rupert Jones, and in conclusion announced the awards of the various Medals and proceeds of Donation-Funds in the gift of the Society. The Report of the Library and Museum Committee enumerated the additions made during the past year to the Society’s Library, announced the completion of about 40 previously imperfect sets of serials, and referred to the registration of type specimens in the Museum, a task which has been confided to a specialist, Mr. C. Davies Sherborn. In handing the Wollaston Medal, awarded to Baron Ferdinand von Richthofen, to Mr. W. Topley, F.R.S., for transmission to the recipient, the President addressed him as follows :— Mr. Topley,—To Baron Ferdinand von Richthofen the Council of the Geological Society has awarded this year the Wollaston Medal in recognition of the great merit of the researches carried on by him over a large part of the Old World and of the New. From the outset of his career he has been distinguished by a rare combination of the power of minute patient observation, with the faculty of broad, and often brilliant, generalization. It is this union of mental gifts which has placed him high among the leaders of science of his time, and which gives such a charm and value to his writings. Beginning his early investigations among the eruptive rocks of his native country, he was gradually led to undertake a detailed investigation of the geology of that interesting region in the South Tyrol around Predazzo and St. Cassian, The elaborate “monograph of this tract, which he published in 1860, was a remarkable achievement for so young a man, ‘and gave ample promise of his future distinction. Soon after its publication he had the good fortune to be attached to a naval Geological Society of London. 183 expedition sent out to the East by the Prussian Government to arrange commercial treaties with China, Japan, and Siam. He was thus afforded opportunities of turning to account his power of rapid observation, of enlarging his geological experience, and of meditating upon those problems to the solution of which he might devote his life. We are all’familiar with the brilliant series of papers and works which has followed from the labours of the twelve years spent by him abroad. Crossing the Pacific he came in contact with Professor J. D. Whitney, who was then conducting the Geological Survey of California. ‘The young and eager German was induced to settle for a time on the Pacific border of the American Continent, where he devoted himself to the study of the marvellous volcanic phenomena of that region. Among the contributions made by him to the geology of the United States, his remarkable generalizations as to the order of succession of the volcanic rocks, and the nature of ‘ massive eruptions’ have attracted special attention. What he had seen of China had convinced him that an investigation of its geology would prove of the utmost interest and value. Accordingly, in the summer of 1868, instead of turning homewards, he returned to that country, and spent somewhere about three years in a series of journeys through the vast Celestial Empire. ‘The massive volumes and splendid atlas which contai his account of China form one of the most important contributions ever made to geological literature. In every chapter there is some luminous remark or suggestive inference that lights up the formidable array of facts with which the pages are crowded. The description of the Chinese Loess and the manner in which the author works out his explanation of that puzzling formation are a model of geological description. As a geologist, a scientific traveller, an exponent of facts, and a generalizer from facts to their connecting cause, Baron von Richthofen stands in the forefront of the science of our day, and in awarding him the Wollaston Medal this Society does itself as much honour as it seeks to conter on him. When you, Mr. Topley, transmit this Medal to him and express to him our appreciation of his labours, will you also convey to him our personal regard and our hope that he may long be able to continue the work which has rendered his name so illustrious. _ Mr. Torrey, in reply, said:—Mr. President,—I am desired by Baron von Richthofen to express his extreme regret that important duties detain him in Berlin, and render it impossible for him to be present here to day. He requests me to offer to this Society his warmest thanks for the honour now conferred upon him, and for placing his name in the list of distinguished geologists to whom this Medal has been awarded. In a letter which | have just received Baron von Richthofen says:—‘“ If I were personally present I would not fail to remark that I am deeply impressed by the consciousness how unfavourably the humble work I have been able to accomplish compares with the honour now conferred upon it; and that it will be my endeavour to render myself more worthy of it by never ceasing to work in the interests of geological and, what is so nearly related to it, geographical science, my line of research being indeed chiefly in that field where both these branches of science meet. ‘‘ British geologists have had the largest share in the geological exploration of other continents than Europe. It has been my lot, too, to do a chief part of my work abroad. This common interest has, among others, contributed to connect me with many of my fellow-workers in science in your country. It is a sincere gratification to me to have this tie strengthened by being put under the obligation of gratitude towards this illustrious Society in which the names of British geologists are embodied.”’ _ The feeling of gratification with which Baron von Richthofen will receive this Medal, will, 1 am sure, be shared by the geologists in Germany and Austria. No one is held in higher honour by them, both for personal worth and scientific attain- ments, than Baron von Richthofen, and to no one would they more gladly see this Medal awarded. The President then presented the Murchison Medal to Prof. A. H. Green, M.A., F.R.S., addressing him as follows :— Professor Green,—In awarding to you the Murchison Medal, the Council desires to mark its sense of the importance of the contributions which you have made to our knowledge of English geology, more particularly in the Coalfield of Yorkshire, with which your name will ever be honourably associated. It might not be appro- priate were I to allow myself to dwell on the special value of your geological 184 Reports and Proceecdings— labours. I will only say that they long ago placed you among the ablest field- geologists of this country. But besides the work done by you in the field, and expressed on maps and sections, we owe a further debt to you for the clear, terse, and interesting descriptions which you have given of your researches. It is always pleasant as well as instructive to read one of your writings, and this eminent faculty of exposition you have turned to valuable account in your admirable ‘‘ Manual of Geology.’’ There is to myself a peculiar pleasure in being the channel through which this Award of the Council comes to you. for I can look on an unbroken friendship with you extending over some thirty years. In banding to you the Medal founded by Murchison, I am reminded of your early intercourse in the Geological Survey under that great leader, when we discussed together the questions to which we have each since devoted ourselves. And I am sure I fulfil the desire of every Fellow of this Society when I express the hope that, in your high position at Oxford and in the original research which you will doubtless still carry on, you may continue for many years that career of distinction which we gladly recognize to-day. Prof. Green, in reply, said:—Mr. President, —Under any circumstances it would be most gratifying to receive from the Geological Society a recognition of my attempts to enlarge the boundaries of our favourite science. But I hold myself specially fortunate on this occasion on two grounds. A Medal that bears the name ot the great chief under whom we both served is specially weleome ; and a further charm is added when I feel that I am receiving this award from one to whom I have been bound in close friendship for a period of more than thirty years. If anything could strengthen the link that binds us together, it would be the receipt of the Murchison Medal at your hands. I thank most cordially the Society and yourself for the honour you have done me. S In presenting the Lyell Medal to Mr. G. H. Morton, F.G.S., the President addressed him as follows :— Mr. Morton,—The Lyell Medal has been adjudged by the Council to you in recognition of your long and meritorious services to geology in the work which you have done around Liverpool. To you we are largely indebted for the extent of our knowledge of the Triassic and other strata’of that district. Your full and accurate account of the glacial phenomena of your neighbourhood forms an especially important part of your labours. In handing you this Medal, with the sincere good wishes of the Council and of the Society, I may add that, had he been alive, no one would have taken a keener interest in your work or rejoiced more heartily at its due recognition than the illustrious founder of this Medal, Charles Lyell. L Mr. Morton, in reply, said:—Mr. President,—I fear that | shall fail, by any words at my command, to adequately express how much I appreciate the great honour conferred on me by the Award of the Lyell Medal. This kind recognition by the Council of any original work that I may have done is most gratifying, for it is the greatest honour that can be bestowed on a geologist. The Medal has been awarded to me before I am too advanced in years to hope to do more work, and it will stimulate me to renewed exertion. The pleasure I now feel is increased at receiving the Medal from your hand, Sir, not only as President of the Geological Society, but as the Director-General of the Geological Survey. I thank you for the complimentary manner in which you have referred to my work in the Triassic and other strata around Liverpool. The President then handed the Balance of the proceeds of the Wollaston Fund, awarded to Mr. Orville A. Derby, F.G.S., to Mr. H. Bauerman, F.G.S., for transmission to the recipient, addressing him as follows :— Mr. Bauerman,—I have the pleasure of handing to you the Balance of the proceeds of the Wollaston Fund for transmission to Mr. O. A. Derby, to whom the Council has adjudged this Award in recognition of the value of his various communications on the Geology and Paleontology of Brazil. Some of these writings have far more than a local interest. I would especially refer to those in which Mr. Derby gives the results of his petrographical researches on the nepheline-bearing rocks, on the distribution of the sources of the rarer minerals, and on the ore-deposits of the Jacapiranga district. In transmitting this Award to him, will you convey the best wishes of the Council and the Society for his continued success in scientific investigation. Geological Society of London. 185 Mr. BavErmay, in reply, said:—Mr. President, —I have been asked, by telegram from Mr. Derby, to represent him, as the interval since the Award was announced has not been sufficient to allow of an acknowledgment by letter. I thank you heartily for the recognition of the excellent work done by Mr. Derby in a country whose geological structure is almost unknown, and I consider that in addition to the honour conferred on the recipient, the Award is of value as likely to encourage the local government in carrying on the systematic investigation of the province in the manner that they have so worthily begun. In presenting the Balance of the proceeds of the Murchison Geological Fund to Mr. Beeby Thompson, F.G.S., the President addressed him as follows :— Mr. Beeby Thompson, —The Balance of the proceeds of the Murchison Fund has been adjudged by the Council to you as a mark of its high appreciation of the insight, endurance, and enthusiasm with which you have prosecuted your laborious investigation of the Upper and Middle Lias of Northamptonshire. Your minute tracing of the successive zones of these formations admirably shows how the Maps of the Geological Survey may be made to serve as the basis for more detailed and exhaustive work, such as can only be undertaken by a permanent resident in a district. We hope that this Award may encourage you to persevere by showing how cordially you possess the sympathies of this Society. Mr. Bersy Tuompson, in reply, said :—Mr. President,—I feel greatly the honour that has been conferred upon me by the present Award. I am a comparatively young geologist, and commenced the study of the science some twelve years ago in connexion with the Northamptonshire Natural History Society. My highest ambition at first was to give a connected réswmé of all that had been published on the local geology; but I soon found deficiencies in the record, and these I have since done my best to supply. 1t is now one of the greatest pleasures of my life to go out into the field and interrogate the rocks; and although we frequently come to violent blows, I hope we shall ever remain the best of friends. { thank you, Sir, for the kind and encouraging words with which you have accompanied this presentation. The President then presented one-half of the Balance of the pro- ceeds of the Lyell Geological Fund to Mr. J. W. Gregory, B.Sc., ¥.G.8., addressing him as follows :— Mr. Gregory,—One moiety of the Balance of the proceeds of the Lyell Fund has been assigned by the Council to you as a token of its warm appreciation of your researches and as an encouragement to you to continue them. You have shown yourself to be an accomplished paleontologist and an able petrographer; and we trust that in both capacities you may live amply to fulfil the promise which you have given of a brilliant career in the future. Mr. Gregory, in reply, said:—Mr. President,—The Fund which the Council has so kindly awarded me helps me to realize more than usual the responsibility of holding an appointment at the Natural History Museum, for I feel that it to the opportunities afforded by its collections and libraries, and by the generous assistance and encouragement of the more experienced members of the staff, that the little that I have been able to do is entirely owing. You, Sir, have kindly re- ferred to the fact that I have occasionally wandered from the work of descriptive paleontology; I can only offer as an excuse for thus presuming to intrude into the other branch of geological work, the desire occasionally to exchange the air of the museum for that of the field, as well as the wish for the training acquired in pursuing the more precise method of research. This Award will encourage me to try to continue in the path of its founder in regarding fossils not merely as the cells of a phylogenetic tree, but as the witnesses from whose evidence we must learn the physical conditions and faunistic migrations of the successive periods of the past. In presenting the other half of the Balance of the proceeds of the Lyell Geological Fund to Mr. Edwin A. Walford, F.G.S., the President addressed him as follows :— 186 Reports and Proceedings— Mr. Walford,—The Council has awarded you the other moiety of the Lyell Fund in recognition of the great merit of your studies among the Lias and Lower Oolites and your contributions to our knowledge of the Trigonie and Polyzoa of the Jurassic rocks. We hope that you will accept this Award as an aid and stimulant to further research, and that we may have the pleasure and profit of continuing to receive the results of your labours. Mr. Watrorp, in reply, said:—Mr. President,—I thank you for this recognition of such work as I have done. My stratigraphical labours have consisted principally in filling in the details of the broad outlines so well laid down by the officers of the Geological Survey. In paleeontology my work among the Mollusca and Bryozoa has been done in the few intervals of leisure snatched from a busy business life. I wish that I had been able to accomplish more, for what I have done is but’ evidence of what I would wish to do. The President then handed the proceeds of the Barlow-Jameson Fund, awarded to Prof. C. Mayer-Eymar of Ziirich, to Dr. W. T. Blanford, F.R.S., addressing him as follows :— Mr. Blanford,—In asking you to be so good as to transmit to Prof. Mayer-Eymar a donation from the Barlow-Jameson Fund, awarded to him by the Council, 1 hope that you will convey to him an expression of the interest we take in the work he is now carrying on so vigorously in Kgypt, and of our desire to aid him in it. His previous training in the paleontology of the Cretaceous and Tertiary rocks of Switzerland, France, and Italy eminently qualified him for the task to which he is now devoting himself, and in which we sincerely wish him success. Dr. Buanrorp, in reply, said:—Mr, President,—I am very pleased to undertake the duty of transmitting the Award from the Barlow-Jameson Fund to Professor Charles Mayer-Eymar. The money will be devoted to one of the most important objects for which these funds were originally founded—the payment of the travelling expenses of a geologist who is engaged in investigating the structure of a distant country. Prdlesot Mayer-Eymar, in a letter from Cairo written on the 4th of the present month, asks me to convey his thanks to the Society, expresses his warm acknowledg- ment of the assistance to his work that the present Award will give, and promises, as evidence of his gratitude, to send in the course of next month, for the information ‘of the Society, an account of his three principal stratigraphical discoveries in Egypt. The Prestpent then said:—Before passing from the subject of the Awards, I should like to refer very briefly to the remarkable and interesting coincidence that this Anniversary day of our Society is also the centenary of one of the great geologists who founded our Medals and Funds. Exactly one hundred years ago (viz. on February 19th, 1792) Roderick Impey Murchison was born. Twenty years have passed away since he was removed from our midst; and at this distance of time we can better estimate the value of his work and its influence on the progress of our science. I do not purpose, on the present occasion, to attempt such a critical estimate. I am sure, however, that I express not my own feeling only, but that of every Fellow of the Society, when I say that though we have been able to correct some of his observations, and discard some of his deductions, the solid work which he accomplished, more especially in the establishment of his Silurian system, stands on a basis which seems even stronger and broader now than when he laid it more than half a century ago. His name has become a household word in Geology, and will go down to future ages as that of one of the great pioneers of the science. To those who knew him personally and learnt to appreciate the frank, generous, and sympathetic nature that underlay the somewhat formal bearing of the old soldier, this day brings many pleasing memories. That the recollection of his personal worth remains yet fresh without as well as within the pale of our Society has been vividly brought to my knowledge by an incident as unwonted as it is gratifying, Within these few days an old friend of Murchison, who desires to remain unknown, has come to me with the wish to be allowed to offer here a tribute to his memory at this Anniversary of the Geological Society and centenary of his birth. As a mark of sincere admiration for the man as well as the geologist, and with the view of helping to encourage the cultivation of the spirit in which he laboured, I have been asked to select two geologists, by preference Scotsmen, who are disciples of Murchison, or who are carrying on the kind of research to which he devoted himself. ‘lo each Geological Society of London. . 187 of these workers the generous donor asks to be allowed to give a framed portrait of Murchison together with a sum of £50. The conditions of the gift circumscribed my choice, but I feel confident that I shall carry the Society with me when I say that there are pre-eminently two Scottish geologists who have worthily followed in Murchison’s footsteps, but with no slavish regard for the opinions of their master, who are continuing and extending his work, and who by their constant association alike in the field and in descriptive writing deserve to share in this tribute to the memory of their former chief. I need hardly say that I allude to Mr. B. N, Peach and Mr. John Horne. The President then presented an envelope containing a cheque for £50 to Mr. B. N. Peach, and requested him to convey a similar packet to Mr. J. Horne. . Mr. Peacs, in reply, said:—Mr. President,—On behalf of my colleague, Mr. Horne, and myself I beg to thank you for your kindness in considering that we have carried on the work of our old chief, Sir Roderick Murchison, in the true spirit, and I beg to request that you will convey our thanks to the unknown donor of this munificent gift. The President then proceeded to read his Anniversary Address, in which he first gave Obituary Notices of several Fellows, Foreign Members, and Foreign Correspondents deceased since the last Annual Meeting, including Sir Andrew Ramsay (President in 1862-63), Prof. P. Martin Duncan (President in 1876-77), the Duke of Devon- shire (elected in 1829), Mr. R. B. Grantham (elected in 1833), Prof. J. Leidy (elected Foreign Member in 1866), Prof. Ferdinand von Roemer (elected Foreign Member in 1859), Baron Achille de Zigno (elected Foreign Correspondent in 1886), the Earl of Northesk, Mr. Frederic Drew, Mr. J. Thornhill Harrison, Sir J. Hawkshaw, ‘Mr. Thos. Roberts, Mr. C. S. Wilkinson, Mr. Kinsey Dover, and Mr. Collett Homersham. The other portion of the Address was devoted to a continuation of the subject treated of last year, and dealt with the history of volcanic action in this country from the close of the Silurian period up to Older Tertiary time. The remarkable volcanic outbursts that took place in the great lakes of the Lower Old Red Sandstone were ‘first described. From different vents over Central Scotland, piles of Java and tuff, much thicker than the height of Vesuvius, were accumulated, and their remains now form the most conspicuous hill- ranges of that district. It was shown how the subterranean activity gradually lessened and died out, with only a slight revival in the ‘far north during the time of the Upper Old Red Sandstone, and how it broke out again with great vigour at the beginning of the Carboniferous period. Sir Archibald pointed out that the Carbon- iferous volcanoes belong to two distinct types and two separate epochs of eruption. The earlier series produced vast submarine lava-sheets, the remains of which now rise as broad terraced plateaux over parts of the Lowlands of Scotland. The later series manifested itself chiefly in the formation of numerous cones of ashes which were dotted over the lagoons and shallow seas. After a long quiescence, volcanic action once more reappeared in the Permian period, and numerous small vents were opened in Fife and Ayrshire and far to the South in Devonshire. With these eruptions the long record of Palzozoic volcanic activity closed. No trace has yet been 188 Reports and Proceedings— discovered of any volcanic rocks intercalated among the Secondary formations of this country, so that the whole of the vast interval of the Mesozoic period was a prolonged time of quiescence. At last, when the soft clays and sands of the Lower Tertiary deposits of the South-east of England began to be laid down, a stupendous series of fissures was opened across the greater part of Scotland, the North of England, and the North of Ireland. Into these fissures lava rose, forming a notable system of parallel dykes. Along the great hollow from Antrim northwards, between the Outer Hebrides and the main- land of Scotland, the lava flowed out at the surface and formed the well-known basaltic plateaux of that region. The address concluded with a summary of the more important facts in British volcanic history bearing on the investigation of the nature of volcanic action. Among these the President laid special stress on the evidence for volcanic periods, during each of which there was a gradual change of the internal magma from a basic to an acid condition, and he pointed out how this cycle had been repeated again and again even within the same limited area of eruption. In conclusion, he dwelt on the segregation of minerals in large eruptive masses and indicated the importance of this fact in the investigation, not only the constitution and changes of the volcanic magma, but also of the ancient gneisses where what appear to be original structures have not yet been effaced. The Ballot for the Council and Officers was taken, and the following were duly elected for the ensuing year:—Council: Prot. J. F. Blake, M.A.; Prof. T. G. Bonney, D.Se., LL.D., F.R.S.; James W. Davis, Esq., F.L.S., F.S.A.; R. Etheridge, Esq., F.R.S.; L. Fletcher, Esq., M.A., F.R.S.; Prof. C. Le Neve Foster, D.Sc., B.A.; Sir A. Geikie, D.Se., LL.D., F.R.S.; Alfred Harker, Esq., MYAL; Hi. Hicks; Esq..°M.D., F:RiSo)"G. J: Hinde, Esq.) Ph Dos Weeds Hudleston, Esq., M.A., F.R.S.; Prof. T. McKenny Hughes, M.A., F.R.S.; J. W. Hulke, Esq., F.R.S.; Prof. J. W. Judd, F.R.S.; J. E. Marr, Esq., M.A., F.R.S.; H. W. Monckton, Esq. ; Clement Reid, Esq., F.L.S.; J. J. H. Teall, Esq., M.A., F.R.S.; W. Topley, Esq., F.R.S.; Prof. T. Wiltshire, M.A., F.L.S.; Rev. H. H. Winwood, M.A.; H. Woodward, Esq., LL.D., F.R.S.; H. B. Woodward, Esq. OrricEers.— President: W.H. Hudleston, Esq., M.A.. F.R.S. Vice- Presidents ; Prof. T. G. Bonney, D.Sc., LL.D., F.R.S.; L. Fletcher, Esq.; M.A., F.R.S.: G. J. Hinde, Esq., Ph.D.; Prof. J. W. Judd, F.R.S. Secretaries: H. Hicks, ¥sq., M.D., F.R.S.; J. E. Marr, Esq., M.A., F.R.S. Foreign Secretary: J. W. Hulke, Esq., F.R.S. Treasurer: Prot. T. Wiltshire, M.A., F.L.S. The thanks of the Fellows were unanimously voted to the retiring Members of Council: Dr. W. T. Blanford, Dr. J. Evans, James Carter, Esq., J. C. Hawkshaw, Esq., and F, W. Rudler, Esq. Il.—February 24, 1892.—W. H. Hudleston, Esq., M.A., F.B.S., President, in the Chair.—The following communications were read : 1. “The Raised Beaches, and ‘Head,’ or Rubble-Drift, of the South of England; their Relation to the Valley-Drifts and to the Glacial Period; and on a late Post-Glacial Submergence.—Part II.” By Joseph Prestwich, D.C.L., F.R.S., F.G.S. (For Part I. see p. 136.) The ossiferous deposits of the Caves of Gower are shown to be contemporaneous with the raised sand-dunes between the beaches and the ‘head,’ and reasons are given for supposing that the eleva- tion of land which preceded their formation need not necessarily have been greater than 120 feet. The mammalian fauna of these Geological Society of London. 189 caves is the last fauna of the Glacial or post-Glacial period, and the ‘head’ or Rubble-drift marks the closing chapter of Glacial times. Evidence is given for considering that the ‘ Rubble-drift’ has a wide inland range, and that to it are to be referred the ‘ Head’ of De la Beche, the Subaerial Détritus of Godwin-Austen, the Angular flint drift of Murchison, and in part the ‘trail’ of Fisher and the ‘warp’ of Trimmer, as well as other deposits described by the author, The accumulation is widespread over the South of England, and occurs in the Thames Valley, on the Cotteswold Hills, and on the flanks of the Malverns. The stream-tin détritus of Cornwall and the ossiferous breccia filling fissures (which must be distinguished from the ossiferous deposits of the true caves) are held to be repre- sentatives of the ‘ Rubble-drift,’ which is of a variable character. The author discusses the views of previous writers on the origin of the accumulations which he classes together as ‘ Rubble-drift,’ and points out objections to the various views. He considers that they were formed on upheaval after a period of submergence which took place slowly and tolerably uniformly: and that the absence of marine remains and sedimentation shows the submergence to have been short. This submergence cannot have been less than 1000 feet below present sea-level, and was shortly brought to a termination by a series of intermittent uplifts, of which the ‘head ’ affords a measure, sufficiently rapid to produce currents radiating from the higher parts of the country, causing the spread of the surface-détritus from various local centres of higher ground. The remains of the Jand animals killed during the submergence were swept with this débris into the hollows and fissures on the surface, and finally over the old cliffs to the sea- and valley-levels. Simul- taneously with this elevation occurred a marked change of climate, and the temperature approached that of the present day. The formation of the ‘head’ was followed in immediate succession by the accumulation of recent alluvial deposits; so that the Glacial times came, geologically speaking, to within a measurable distance of our own times, the transition being short and almost abrupt. In this paper only the area in which the evidence is most com- » plete is described. The author has, however, corroborative evidence of submergence on the other side of the Channel. 2. “The Pleistocene Deposits of the Sussex Coast, and their Equivalents in other Districts.” By Clement Reid, Esq., F.L.S., F.G.S. (Communicated by permission of the Director-General of the Geological Survey.) The gales of last autumn and early winter exposed sections such as had not before been visible in the Selsey Peninsula. Numerous large erratic blocks were discovered, sunk in pits in the Bracklesham Beds. These erratics included characteristic rocks from the Isle of Wight. The gravel with erratics is older, not newer as is commonly stated, than the Selsey ‘mud-deposit’ with southern mollusca. Numerous re-deposited erratics are found in the mud-deposit, which is divisible into two stages, a lower, purely marine, and an upper, or Scrobicularia-mud, with acorns and estuarine shells. 190 Reports and Proceedings—Geological Society of London. At West Wittering a fluviatile deposit. with erratics at its base and stony loam above, is apparently closely allied to the mud- deposit of Selsey; it yields numerous plants, land and freshwater mollusca, and mammalian bones, of which lists are given. The strata between the brickearth (= Coombe Rock) and the gravel with large erratics yield southern plants and animals, and seem to have been laid down during a mild or interglacial episode. A similar succession is found in the Thames Valley and in various parts of our eastern counties. Ifl.—March 9, 1892.—W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.—The following communications were read : 1. “The New Railway from Grays Thurrock to Romford : Sections between Upminster and Romford.” By 'T. V. Holmes, Esq., F.G.S. In the Hornchurch cutting of the new railway, Boulder-clay, of which about 15 feet is seen, rests upon the London-clay near the 100-feet contour-line, and is overlain by 10 to 12 feet of sand and gravel. The author gives reasons for inferring that this sand and gravel belong to the oldest terraces of the Thames Valley gravel occurring in this district, and states that it demonstrates the truth of Mr. Whitaker’s conclusion that the Thames Valley deposits are (locally) post-Glacial, or newer than the local Boulder-clay. 2. “The Drift Beds of the North Wales and Mid-Wales Coast.” By T. Mellard Reade, Hsq., C.E., F.G.S. This paper is a continuation of papers by the author on the Drift Beds of the N.W. of England and North Wales. The author first treats of the Moel Tryfaen and other Caernarvonshire drifts; he describes the drifts of the coast and coastal plain, connecting his observations with those of the Moel Tryfaen drifts. An important feature of the investigation is the numerous mechanical analyses of the various clays, sands, and gravels. In all the samples but one, a large -proportion of extremely rounded and polished quartz-grains have been found, which the author maintains to be true erratics, and a certain sign of marine action. He shows that the Moel Tryfaen marine sands are in part overlain by typical Till, composed almost wholly of local rocks with a small percentage of clay, whereas the sands and gravels are full of erratics including rocks from Scotland and the Lake District, numerous flints, Carboniferous Limestone, and crystalline schists. Throughout the drifts of the coastal plain he has found a greater or less proportion of granite erratics, as well as, in many cases, minute rolled shell-fragments. He maintains that these drifts are the result of two opposing forces, one radiating from Snowdonia, and the other acting from the sea to the southwards, and their characteristics change as the one or the other force pre- ponderated. The other divisions of the paper are taken up with a description of the Merionethshire drift and that of Mid-Wales, numerous sections being given. Attention is called to a remarkable glaciation of the rocks at Barmouth. In a concluding part, giving inferences and suggestions, the author Correspondence—Mr. Mellard Reade—Mr. J. Lomas. 191 discusses the land-ice and submergence hypotheses, and concludes: that his observations distinctly strengthen the grounds for believing” in a submergence of the land to an extent of not less than 1400 feet. An Appendix contains details of nineteen mechanical analyses of tills, sands, and gravels, and a bibliography of papers, observations, and theories of the high-level drifts of Moel Tryfaen. CORRESPONDENCE. READE’S THEORY OF MOUNTAIN BUILDING. Srr,— Mr. Jukes-Browne seems to holds peculiar, not to say ex- acting, views of the way scientific controversy should be conducted. Having replied to Mr. Davison’s criticisms on a fundamental principle, without a rejoinder from him, though nearly a year has since elapsed, I am now invited to go on answering him until some unnamed but ‘good physicists” are satisfied. I need hardly say that this is a labour I must decline. At the same time, I am ready to meet fairly any good physicists who are prepared to speak in their own names. T. Metuarp Reape. March 9th, 1892. ON A FAULT WITHOUT A THROW. ‘Srr,—The north-western part of the Wirral—the district forming the western horn of Cheshire—is very extensively faulted. The prevailing direction of the faults is north and south, but at places east and west faults are met with. These abut against the north and south faults and are generally terminated by them. A remarkable characteristic of many of these east and west faults is that although they possess slickensided faces and there is evidence of great movements, there is little or no throw. _ A very good example is now exposed near Caldy Grange Grammar School, West Kirby. There is a fine flank exposure of a north and south fault just behind the school. It was described by Mr. O. W. Jeffs in 1887 (Proc. Liverpool Geol. Soc. vol. v. p. 247). He men- tioned three east and west faults which terminated against the main fault. Since that time another east and west fault has been exposed and was described by Messrs. Beasley and Lomas before the Liver- pool Geological Society in February, 1892. This fault has been traced westwards from the main fault for about a third of a mile, and in one part forms a ridge of fault-rock beautifully slickensided about 6 feet wide and rising like a wall above the surrounding Upper Bunter to a height of 6 to 8 feet. A transverse section is seen in a little cutting west of the Water- works, and the beds are continued across the fault without the slightest displacement. Similar east and west faults have been noticed at Storeton and other places, but, so far as I can ascertain, no satisfactory theory has been advanced to explain their peculiarities. In the Caldy Grange fault the Keuper has been faulted down against the Bunter. It does not follow that the Keuper would move 19%. Obituary —UMr. Henry Norton, F.GLS. at the same rate or at the same time along the whole distance of the north and south fault. If we grant differential motion, the matter is explained. The Keuper might slip to a certain point and fracture there, then the other portion falling would slickenside the face, and a throw equal to that of the main fault might leave no residual throw. J. Lomas, Assoc. N.SS. (OeSsEIl UY NIRS HENRY. .NORMON, F.G.S: By the death of Henry Norton, of Norwich, we have to record the loss of an enthusiastic student of Norfolk geology, and one of the most learned men of the present century. He was the son of William Norton, Esq., of Old Buckenham, and in his youth was articled to Messrs. Mitchell & Clarke of Wymondham, and afterwards set up practice as a solicitor in Surrey Street, Norwich. Possessed of ample means, he relinquished his profession to devote himself to travelling in the Hast and throughout Europe. Once, no doubt because of the eccentricity of his conduct, he was apprehended in Vienna as a spy. For many years Mr. Norton devoted himself to the study of Sanskrit, Syriac, Chinese, and other Eastern languages, in which he became so proficient that he was able to read the works of Eastern philosophers and savants in their own tongue. He was also a good Scandinavian and German scholar. Of late years he applied himself a great deal to the study of modern science and philosophy, and more especially to the geology of Norfolk. He joined the Norwich Geological Society when it was first established in 1864, and became a Fellow of the Geological Society of London in 1875. He examined in great detail the sections at Pakefield and Kess- ingland, and read before the Norwich Society a paper in 1876 (published in the ‘Norfolk Chronicle’ for May 6). A subsequent communication on the ‘Forest Bed of East Norfolk’ was issued separately (reprinted from the ‘Norwich Mercury’ of May 5, 1877); and in this paper he boldly and acutely discussed the evidence that had been published on the subject of stumps of trees being rooted in situ in the Cromer Forest Bed. He showed that the published evidence was inconclusive. In 1877 Mr. Norton contributed some notes on species of Hydrobia from the Freshwater Beds of Runton and Mundesley (Proc. Norwich Geol. Soc. vol. i. p. 16). In 1879 he read a paper embodying great research on the Atlantis Island, coming to the conclusion that it was in reality the continent of Africa (Proc. N.G.S. vol. i. pp. 75, 80). In 1880 he communicated to the same society (Ibid. p. 110) notes on the Paleontology of the Ancients (Greeks and Romans); and also an explanation of the word “ Paramoudra” (Ibid, p. 182). He died in February last, in his 80th year. [Some further particulars of his life were given in the “ Hastern Daily Press ” of February 24. ] eed nak Oty fa , bi aot Geol. Mag.1892. DecadellIVel XP1L.V. Pa se 7 la G M Woodward. delet hth. | Paleeotermes: Ellisu, WH. Woodw. Lower Lias. Barrow-on-Soar ke. THE GEOLOGICAL MAGAZINE. NEW SERIES. -DECADEM MI »VOLe IX, No. V.—MAY, 1892. ORIGINAL ARTICLES. —>—__ I.—On a NeEvrorterous Insrot rrom THe Lower Las, Barrow-on-Soark, LEICESTERSHIRE. By Henry Woopwarp, LL.D., F.R.S., F.G.S8., of the British Museum (Natural History). (PLATE VY.) O much attention has been bestowed of late years on fossil organic remains from rocks of all ages, that it must appear surprising to find so little notice has been directed to the Insect- remains from the British Secondary rocks. It is now nearly fifty years since that veteran geologist, the Rev. P. B. Brodie, M.A., F.G.S., published his modest little Svo. volume entitled ‘A History of the Fossil Insects in the Secondary Rocks of England”? which is still the only separate work of the kind extant. Numerous Insect-remains have, it is true, been described by Prof. J. O. Westwood, Mr. H. H. Strickland, Prof. J. F. Blake, Mr. A. G. Butler, and Mr. 8. H. Scudder, from English rocks of Secondary age; and Mr. Herbert Goss has given an excellent summary of our knowledge of the Mesozoic Insects in the Proceedings of the Geo- logists’ Association (1879). Although fossil insects are rarely well-preserved in our Secondary rocks, yet it cannot be doubted that they were extremely abundant during this period, their remains having been obtained from the Wealden beds of Hastings, Tunbridge, and Maidstone; the Purbeck beds of Durl’ston Bay, of Swanage, and Ridgway, Dorset, have also long been known to yield such organisms, many of them having been figured and described by Brodie and Westwood; whilst the “‘Tnsect-limestone” in the Purbeck strata of the Vale of Wardour in Wiltshire, was formerly the happy hunting ground which furnished the materials for Brodie’s History of Fossil Insects. Traces of Insects have likewise been obtained from the Kimmeridge Clay, the Oxford Clay, Forest Marble, Great Oolite, Stonesfield Slate, and lastly from the Lias and Rheetics. Mr. Herbert Goss, F.G.S.,? in his excellent summary of the Insect Fauna of the Secondary Period, writes as follows :— “The Lias and Rhetic formations are the oldest rocks of this period in which fossil insects have been detected in England. In 1 London, 8vo. pp. xviii. and 130, with 11 plates, 1845. * See ‘‘The Insect Fauna of the Secondary or Mesozoic Pericd, and the British and Foreign Formations of that Period in which Insect-remains have been detected,’’ by Herbert Goss, F.L.S., F.G.S., Proc. Geologists’ Association, 1879, vol. vi. pp. 116-150. DECADE III.—VOL. IX.—NO. V. 13 194 Dr. H. Woodward—On a New Lias Insect. some of the minor divisions insect-remains have been discovered in such abundance that the beds containing them have, as in the ‘Purbecks,’ been called ‘Insect- Limestone.’ Fossil insects have been found, chiefly in the lower division of this formation, in Gloucestershire,’ Worcestershire, Warwickshire, Somersetshire, Dorsetshire, and on the borders of Monmouthshire; a few have also been found in Yorkshire.” They are generally in a much more fragmentary condition than those from the ‘ Purbecks,’ and are less common than in the latter formation. “Mr. Brodie states that he first discovered these interesting fossils in the immediate neighbourhood of Gloucester,® and he adds, that some of the beds of limestone in the lowest division of the Lias, in the Vale of Gloucester, abound in insects; and that beautiful specimens, chiefly elytra and wings, have also been found in the Upper Lias at Dumbleton and Alderton. ‘* At Dumbleton, which is N.E. of Cheltenham, Mr. Brodie obtained from the Upper Lias shales one nearly perfect Neuropterous insect, of which Prof. Westwood says‘: ‘It possesses an arrangement of the wing-veins differing from that of any English species, and also from any foreign species known to me, but it comes nearest to the small Libellule ‘forming the genus Diplaw.’ “In the Upper and Middle portions of the Lower Lias, which are extensively developed in the neighbourhood of Gloucester and Cheltenham, traces of insects are anid to be exceedingly scarce ; but at Wainlode Cliff, on the banks of the Severn, near Gloucester, the Insect Limestone has produced remains of several genera of Coleoptera. In the Insect-Limestone to the south-west of Combe Hill, not far from the last-mentioned locality, Mr. Brodie obtained a great number and variety of insect-remains, consisting chiefly of the elytra of Coleoptera, and a few imperfect but large wings of Libellulide. “At Apperley, near Wainlode Cliff, remains of insects have been found in plenty, many small slabs, three or four inches square, exhibiting several elytra and wings, and a few small Beetles. “From the Insect-Limestone, near the village of Hasfield, Glouces- ter, many elytra of Coleoptera have been obtained. The same formation, in the neighbourhood of Forthampton, near Tewkesbury, has also furnished fossil insects, belonging to the same families as those found in the localities before mentioned. 1 In a note at p. 378 of the Quart. Journ. Geol. Soc. vol. x. 1854, Prof. Westwood states that ‘‘ A rich collection of fossil insects, from the Lias of Gloucester- shire, etc., has been made by Mr. W. R. Binfield, to whom also the Museum of the Geological Society is indebted for a suite of insects from the Lias of Lyme Regis.’ 2 The Rey. J. F. Blake has described and figured two fragments of insects from the Yorkshire Lias. One specimen consists of an elytron of a beetle, named by Mr. Blake Buprestites bractoides, and the other specimen consists of two wings of a Neuropterous insect, apparently belonging to some species allied to Chauliodes; which Mr. Blake has named Chauliodites minor. See “ Yorkshire Lias,’’ by Ralph Tate and J. F. Blake, London, 1876, p. 426, pl. xvi. figs. 5 and 6. 3 See Brodie’s “ Fossil Insects,’’ pp. 51-108, and the Quart, Journ. Geol. Soc. vol. iv. 1846, pp. 14-16. 4 See Quart. Journ. Geol. Soc. vol. y, 1849, pp. 31-35. Dr. H. Woodward—On a New Lias Insect. 195 “At Strensham, about nine miles from Evesham, insects have been obtained from a bed of Insect-Limestone at the bottom of a large quarry. Amongst them was found part of the abdomen of a gigantic species of Libellula, which Mr. Brodie named Libellula Hopei. In the neighbourhood of Evesham the Insect-Limestone has produced numerous remains of insects, the wings and elytra of many of which are said to be beautifully preserved. In the lower division of the Lias, in this neighbourhood, Mr. H. H. Strickland’ discovered small elytra of Coleoptera and portions of the wings of Libellulide. “From one quarry near Bidford, Warwickshire, Mr. Brodie obtained a small species of the family Gryllide, which he named Gryllus Bucklandi in honour of Professor Buckland. “In some of the quarries in this neighbourhood (Bidford) the wings of Libellulide were obtained, particularly at a place called the ‘ Nook,’ where a beautiful specimen was found, which has been described and figured by Mr. Strickland.? “Mr. HE. T. Higgins obtained from the Lower Lias or the Rheetics, in the southern parts of Gloucestershire and the adjoining county of Somerset, in the neighbourhood of Bristol, numerous remains of insects. From Aust, near Bristol, and from Sudbury on the Mon- mouthshire side of the Severn, about three miles from Chepstow, the Insect-Limestone and the ‘Landscape-Stone’ have afforded a quantity of remains. In some slabs the insects were found imbedded together in masses. In one slab, Mr. Higgins is stated to have detected as many as 30 small Beetles. “From the frequency of such delicate creatures as insects in the ‘Landscape-Stone,’ and in another band of Limestone, only a few feet higher, some of which are said to be beautifully preserved, and could not have been long subject to the action of the waves, it is supposed by Mr. Brodie, that this part of the Lias may have been formed in an estuary, which received the waters of some neighbouring coasts, and which brought down the remains of insects and plants. “ Ooleoptera appear to have been abundant in the Lias, for out of some 300 specimens, or parts of specimens of insects, obtained from this formation, examined by Professor Westwood, more than one- third were referred by him to this order, and included representa- tives of the Buprestida, Elateride, Curculionide, Chrysomelide, Cara- bide, Telephoridea, etc. ‘Most of the species appear to have been very minute, never equalling in size,’ observes Mr. Westwood, ‘those from the Stonesfield Slate.’ The other orders represented in this formation are the Orthoptera, the Neuroptera, the Hemiptera, and (possibly) the Diptera ? “The remains of Orthoptera include Gryllide and Blattide; the Hemiptera include Cicada and Cinnee, and the Neuroptera, Libellula, Agrion, Orthophlebia, Hemerobius, Aischna, Chauliodes and Ephemera. Among these various families and genera we have omnivorous, herbaceous, and predaceous species. Many of the families and genera found in the Lias are common both to it and the Purbecks. 1 Quart. Journ. Geol. Soc. 1846, vol. iv. pp. 14-16. : ? See Mag. Nat. Hist. vol. iv. 1840, pp. 801-303, and woodcuts (New Series). 196 Dr. H. Woodward—On a New Lias Insect. “ Although, as a rule, the remains of insects from this formation are very imperfect and fragmentary, the detached wings of many Neuropterous insects are preserved in the greatest perfection, and have the nervures of the wings beautifully defined. The size of the insects, judging from the remains, appears to have been usually small and indicative of a temperate climate. “Tt may be observed that nearly all the fossil-insects from this formation have, with the exception of a few specimens from the Upper division, been obtained from the lowest! division of the Lias, or from the Rheetic series, between the Lias and the Trias. Remains of insects from the Lias and Rhetics are very numerous, but the majority of them are in such a fragmentary condition that it has been impossible, even for those who have devoted special attention to the subject, to make out the species to which they belong. About 56 species, however, have been determined, which are dis- tributed amongst five orders as follows, viz. :—Coleoptera, 29 species; Neuroptera, 12; Orthoptera, 7; Hemiptera, 6; Diptera? 2 (supposed). “No traces of Lepidoptera or Hymenoptera have been met with, and the remains which have been referred to the Diptera are extremely doubtful.” For permission to describe and figure the very fine impression of a Lias Insect, which forms the subject of Plate V. Fig. 1, I am indebted to the kindness of Montagu Browne, Esq., F.G.S., Curator of the Town Museum, Leicester, who obtained it from the Lower Lias (Planorbis-zone), Barrow-on-Soar, Leicestershire, in 1889, when spending his vacation there. The insect is, so far as I am aware, unique of its kind asa fossil, and is preserved in almost equal clearness, as an impression and counterpart, upon two very close-grained slabs of Lower Lias Limestone, from which the well-known hydraulic cement is so largely manufactured. The insect itself is 54 milli- metres in length, the fore-legs extending 12 mm. beyond ‘and in front of the head, which is 6 mm. long and 84 mm. broad. The three divisions of the thorax measure 9 mm. long by 84 in breadth. The wings, which are neatly folded together, as in repose, are nearly four times as long as they are wide. In addition to two fore-legs already mentioned, one mandible, part of an antenna, the eyes, and the two hind-legs, are more or less perfectly preserved. The wings are clouded with spots of colour such as one frequently sees in these transparent membranous organs in many living Neuroptera ; such colour-markings have also been figured by Scudder in Mega- thentomum pustulatum from the Coal-measures of Mazon Creek, Illinois, and in his Brodia priscotincta from the same horizon, Tipton, Staffordshire. The tibia and 5-jointed tarsus of the two fore-legs can be very well seen preserved on the slab; the legs are somewhat stouter than in many modern Neuroptera, and the tibia appears to have been slightly serrated or spined, along the inner margin. 1 Mr. Goss mentions that he had received from the late Mr. Charles Moore, of Bath, a large collection of fossil insects from the Upper Lias of Ilminster, This collection included Coleoptera, Neuroptera, Orthoptera, ete. Dr. H. Woodward—On a New Lias Insect. 197 The head is rounded and of moderate size, with a slight indentation, in front, marking the median line. The mandible, which is serrated, can be seen on the right side, and a portion of the left antenna, with its small bead-like joints, is preserved. The eyes are prominent, but moderate in size. The pronotum is not long and cylindrical as in Chauliodes, but is of nearly equal length with the mesonotum and metanotum, but the mesonotum is broadest and is angular in outline. The abdomen is concealed beneath the wings, and its proportions cannot consequently be given. The wings, in their closed position, measure 42 mm. in length, by 12 mm. in breadth, but being folded upon one another, it is a matter of considerable difficulty to trace the nervures belonging to each of the separate wings. To begin with the anterior border. There is an entire absence of the ladder-like cross-veins which unite the costa with the costal vein in the wings of so many Neuropterous insects ; but, apparently, there is a trace of such ladder-like cross-veins to be faintly seen near the distal end of the wings, and within their lateral margins, which may possibly belong to the under, or hind-wings. With regard to its absence in the upper, or front-wings, it may be explained either (a) as not existing; (b) as not having been pre- served; or (c) that the costal margin was folded down out of sight, when the insect was at rest. (a) I do not know of an instance of a Neuropterous insect in which this well-marked marginal line of cross-veins uniting the costal border with the costal-vein, is present in the hind-wings? and absent in the front-wings; (b) yet it seems unlikely, if it existed, that no trace should have been left along the costal margin in either wing; but (c) in a specimen of Chauliodes Japonicus (McL.), with the wings closed (which, by the kindness of Mr. Charles O. Water- house, I have been enabled to examine, together with numerous other insects, in the Zoological Department), the costal margin of the front wings cannot be seen, being folded down out of sight on each side. I have not seen the living insect; but if this is its normal position when at rest, then it may be that the costal border of the wings of this Lias insect are also concealed in a similar manner beneath the rest of the wing. I do not, however, feel confidence in urging this hypothesis. After carefully studying the wings and comparing the relative position of the subcostal, the principal, subnodal, median, and sub- sector veins in recent Neuropterous insects, with the fossil form, I find the points of comparison with Chauliodes less satisfactory than I had at first anticipated, and that both in the narrow and elongated form of the wing, as well as its more simple neuration and the absence of the ladder-like cross-veins on the costal margin, there is a greater resemblance to the Termitide (sub-order Pseudoneuroptera). The very distinct evidence of symmetrically-arranged colour- markings and spots on the wings must not, however, be lost sight 1 As this single line of ladder-like cross-veinlets occurs within the wing, it may not after all belong to the margin of the lower or hind-wing, but form part of the cross-veinlets of the front wing itself (as in Clathrotermes signatus, Heer). 198 Dr. H. Woodward—On a New Lias Insect. of, for they closely resemble those observable in many species of Neuroptera (Chauliodes, Newromus and Palpares), and they do not appear to characterize the wings of Termites, which are uniform in colour. Nevertheless, the late Prof. Oswald Heer, in his “‘ Urwelt der Schweiz” (Zurich, 1865) pp. 85-86, taf. vii., has noticed the wing of a fossil insect from the Lias of Schambelen, Switzerland, with an extremely similar venation to our specimen, and,—it is also very interesting to notice,—with colour-markinys preserved upon its surface. This wing he names Calotermes maculatus. He writes as follows:—‘ At Schambelen six species of Termites have been discovered. They agree with the existing species in the general arrangement of the veins of their wings, but differ from them in many other respects; so that they must be regarded as forming peculiar extinct genera, of which I distinguish two. In one of these (Clathrotermes signatus, Heer), pl. vii. fig. 8, the costal area of the wing is divided by delicate transverse nervures, into a series of quadrangular cells, and the wings are spotted with black; in the other {Calotermes) these transverse nervures are wanting, but the wings are spotted with black in one species (C. maculatus, Heer, pl. vii. fig. 7) and PL. V. Fig. 4, or they have a dark costal area (as in C. plagiatus, Heer, pl. vii. fig. 6). These dark spots and bands are peculiar to the Termites of the Lias; for all the living species have colourless wings. ‘The Liassic species, like those of the present day, differ much in size; the smallest (C. troglodytes, Heer) has wings only 84 lines long; in the largest (C. obtectus, Heer), they attain a length of 9 lines” (English translation by W. 5S. Dallas, London, 1876). The new Termite from Barrow-on-Soar is relatively so very much larger than any of the remains from the Lias of Switzerland, described and figured by Heer, that it cannot be referred to the saline genus, yet it evidently belongs to this peculiar group with spotted wings. Therefore, although I am anxious to avoid the need- less multiplication of generic names, I venture to refer our Lias Insect to a new genus, Palgotermes, very near to Heer’s Calotermes, with the distinctive specific name of Hilisii, by desire of Mr. Browne, in recognition of his indebtedness to Messrs. Hllis, the owners of the Lias Limestone pits at Barrow-on-Soar, who have, for many years, given him special facilities in the prosecution of his researches. EXPLANATION OF PLATE YV. Fic. la. Paleotermes Ellisii, H. Woodw., sp. nov. (enlarged twice nat. size) ; from the Lower Lias (Planorbis-zone), Barrow-on-Soar,' Leicestershire. One-half is preserved in the British Museum (N. H.), and the other in the Leicester Museum. Fic. 14. Plan of wing of same, drawn separately, to show probable arrange- ment of the nervures of the wing. X 2 times. Fic. 2. Detached wing of Chauliodes Japonicus, McL. X 2 times (ad nat.). Fic. 3, Detached wing of Termes angustatus. X 2 times (ad nat.). Fic. 4. Detached wing of Calotermes maculatus, Heer, from the Lias of Scham- belen, Switzerland (copied from Heer’s “ Urwelt der Schweiz.’’). ' The counterpart of this very beautiful Lias Insect has been kindly presented to the British Museum (Natural History) by Montagu Browne, Esq., F.G.S., who has placed the other half in the Leicester Museum. A. Harker—Lamprophyres of North of England. 199 1].—Tue Lampropyyres or tHe Nortu or ENGLAND. By ALFRED Harker, M.A., F.G.S., Fellow of St, John’s College, Cambridge. MY\HE north-country lamprophyres occur usually as dykes of no great magnitude, sometimes as sills, more rarely as small bosses or laccolites. They are scattered over an area extending from Teesdale to Furness, from Bassenthwaite to Ingleton. A circle thus defined has a diameter of about fifty miles, and embraces all the known occurrences, though others may exist beyond these limits concealed by post-Silurian strata. In the centre of the circle is the Shap granite, and the probable genetic connexion between the lamprophyres and this granitic intrusion has already been urged by Mr. Marr and the present writer. The chief grounds for such an opinion are as follows :— (i.) The arrangement of the intrusions, as just noticed, and the radial grouping of the dykes in the central part of the area about the granite. (ii.) The common age of the intrusions, so far as can be fixed ; both granite and lamprophyres being post-Silurian but pre-Carboni- ferous, and both being connected with the same crust-movements. (iii.) Certain general chemical relations, to be noticed below ; to which may be added some special chemical characters, such as the notable quantity of manganese in the granite and in most of the dykes analysed. (iv.) The special mineralogical resemblance of many of the dykes to the Shap granite, shown by the occurrence in them of charac- teristic minerals such as sphene (rarely found in the lamprophyres of other districts), and especially of the well-known porphyritic felspars of the granite. Some of these points are brought out more strongly by comparing the lamprophyres with the dark basic patches so common in the granite. (v.) The arrangement of the different varieties of lamprophyres, the more basic and characteristic ones occurring especially in the outer parts of the area, the more acid varieties and those having most in common with the granite chiefly in the central tract." (vi.) The close association with the lamprophyres of acid in- trusions of types more normal for apophyses of granites, and the existence of transitional varieties between these acid rocks and the lamprophyres. Many of the individual rocks have been described by different writers,” and it will be sufficient here to recall some of the more significant characters which they have in common. The typical 1 It may be remarked here that the lamprophyre of Sale Fell, near Bassenthwaite, which is of a somewhat acid variety, may possibly have had a quite distinct origin. 2 Bonney (analyses by Houghton), Q.J.G.S., vol. xxxv. p. 165; Rutley, did. vol, xxxiv. p. 29, and Mem. Geol. Surv. Ingleborough (97 S.W.) ; Tate, Proc. Yorks. Geol. Pol. Soc. vol. ix. p. 372, vol. x1. p. 311, and Rep. Brit. Assoc. for 1890, p- 814; Hatch, idid. p. 813, and Mem. Geol. Surv. Mallerstang (97 N.W.); Balderston, ‘“‘ Naturalist,’’ 1889, p. 181; Harker and Marr, Q.J.G.S., vol. xlvi. p- 286; Harker, bcd. p. 521; see also Teall, ‘‘ Brit. Petr.’’ chap. x. 200 A. Harker—Lamprophyres of North of England. lamprophyres of the region are exceedingly rich in brown mica, which shows a characteristic mode of alteration by internal bleaching with separation of magnetite or limonite; often also the interposition of little wedges of calcite or dolomite. The mica is often accom- panied by augite in well-formed crystals but usually quite decomposed, and in the Sedbergh district Dr. Hatch records pseudomorphs after olivine. Original magnetite may occur in variable quantity, but in very many cases is entirely wanting. Apatite in fine needles is universal. The ground-felspars include both monoclinic and triclinic species, the relative proportions of the two not being a character of importance. In the more altered rocks the felspars are not to be made out at all, unless the carbonates have been dissolved out of the mass. Original quartz occurs in the ground-mass of the lampro- phyres in the central part of the area only (the Sale Fell intrusion being excluded). Certain porphyritic elements enclosed in the general mass of the rocks, despite their insignificant bulk, are of the highest interest: they are quartz and felspars. Quartz is found in some abundance in the intrusions very near the Shap granite; at greater distances it occurs only sparingly and sporadically, but isolated grains are found even in the dykes at Cronkley in Teesdale. In the acid sills and dykes near the granite the mineral forms sharply-defined pyramidal crystals, in the transitional varieties of rock the crystals are more or less rounded, and in the most typical lamprophyres the quartz occurs in rounded blebs rarely showing any relic of crystal outline. The rounding is clearly due to corrosion by the enveloping magma, and the blebs are commonly bordered by a narrow pale- green rim of rather fibrous hornblende, converted in the more decomposed rocks into a chloritoid substance. Isolated quartz-grains with a corrosion-border of augite or hornblende are known in the lamprophyres of other districts, and have usually been regarded as mechanically caught up from the walls of the dyke. Such a view seems to be merely an @ priori one, based on the improbability of original quartz-grains occurring in basic rocks, and we shall see that the facts are susceptible of a different reading. It may be noted in passing that similar grains of quartz with a corrosion-border of augite are found in various American olivine-basalts, and are clearly shown to be original constituents.’ Very similar in many respects are the phenomena of the porphyritic felspars in our rocks. Both orthoclase and oligoclase are found, as in the Shap granite. In the dykes and sills nearest the granite these minerals occur plentifully ; elsewhere they are, as a rule, sparingly distributed. In the intrusions in the Cross Fell inlier, for instance, an ordinary hand-specimen may show perhaps one crystal, perhaps none; in Teesdale the felspars are absent, but near Ingleton, at an equal distance from the granite, they occur in some of the dykes. The crystals of both kinds of felspar are always well rounded by corrosion in the typical lamprophyres, less markedly so in the more acid varieties and the transitional rocks, and quite intact in the 1 Tddings, Amer. Journ. Science, vol. xxxvii. p. 208 (1888). A. Harker—Lamprophyres of North of England. 201 normal quartz-porphyries. Within a mile of the Shap granite the sills and dykes sometimes enclose large flesh-coloured crystals of orthoclase identical with those in the granite itself, but more or less rounded as in the dark basic patches of the granite. There is, however, a significant difference. The large orthoclase crystals in the dark patches of the granite have a corrosion-border of plagioclase and quartz: in the lamprophyres this feature is not found, but on the other hand the rounded crystals of oligoclase are often bordered with orthoclase. The enveloping magma was in the former case rich in soda, in the latter case rich in potash. It is likely that in other districts special mineralogical relationships exist between lamprophyres and the plutonic masses near which they occur, but unfortunately the rocks have rarely been studied from this point of view. Doss,! in describing the lamprophyres of Dresden, remarks that they enclose orthoclase crystals similar to those of the well- known Plauen’schen Grunde syenite, but rounded by corrosion, and these he regards as mechanically caught up from the syenite. Since the dykes which he studied actually traverse that rock, the expla- nation is of course a possible one, but it does not appear from his description that the crystals have the form of broken fragments, and the case may well be a parallel to that of the Westmoreland rocks. Having in common the general features outlined above, the north- country lamprophyres still show very considerable variations. The silica-percentage in Mr. Houghton’s eight analyses ranges from 60 to less than 40, that of the Shap granite being 69. The figures for _the more basic rocks are necessarily unsatisfactory, owing to extreme decomposition, some examples having nearly 80 per cent. of car- bonates. The associated acid intrusives and transitional varieties occur well characterized in the centre of the area and to a consider- able distance from the granite, but they do not extend so far as the true lamprophyres. They are well developed in the Cross Fell inlier; but some of the acid rocks there are not demonstrably con- nected with the post-Silurian intrusions, and are possibly Ordovician. In the Sedbergh district the lamprophyres and the acid intrusives are quite distinct, though closely associated, and Mr. Strahan remarks that the former intersect the latter. Rosenbusch makes the same observation in Alsace, and it is probably of some generality. The two sets of rocks, though genetically connected, were derived from different portions of the heterogeneous parent-magma, and the general rule appears to be that the injection of the quartz-porphyries, microgranites, ete., slightly antedated that of the lamprophyres. Where transitional varieties occur, we may suppose either that they were supplied from an intermediate portion of the magma-reservoir, or that an intermixture of the acid and lamprophyric magmas took place during the injection. The striking variability of the rocks in some localities must be due to the latter cause, for in some cases the commingling of the two magmas has been very incomplete. A dyke near Gill Farm exhibits abrupt transitions from quartz-por- phyry to lamprophyre, such as admit of no other explanation than 1 Tsch. Min. Mitth.. (2) xi. p. 27 (1890). 202 A. Harker—Lamprophyres of North of England. that offered. Again, Mr. Houghton’s analyses of two rocks from the same locality on Docker Fell show a sharp contrast, their silica- percentages differing by more than 10. Professor Bonney concludes that the two specimens cannot be really from the same dyke, but Mr. Collins in his analyses of Cornish lamprophyres shows an even greater difference between two specimens taken in situ from one mass. A few words on lamprophyres in general will not be out of place at this point. From quite early days such rocks as minette and kersantite have been recognized as interesting types, not very sharply divided from one another, but collectively occupying a position somewhat apart from what may be regarded as more normal igneous rocks. It is true that the principle of classifying rocks by a mere enumeration of their constituent minerals has led some geologists to confuse these types with the mica-bearing syenites and diorites ; but such a view is not in harmony with either chemical relationships or geological occurrence. To the field-geologist the rocks in question have always been known as characteristically ‘“‘dyke-rocks”’; more recently they have been shown to occur also as special marginal facies of certain deep-seated bodies of rock. Rosenbusch (1887) distinctly recognizes the individuality of the group, for which he adopts von Giimbel’s name lamprophyre.’ He points out its peculiarities, and separates from the two types already mentioned two others, under the names vosgesite and camptonite, in which the dark mica is more or less replaced by hornblende or augite. He makes, however, a division of the group into a ‘syenitic’ and a ‘dioritic’ family, which seems to be quite artificial. It is noteworthy that most of the best known lamprophyres are found in association not with syenites or diorites, but with granites. A glance over Rosenbusch’s lists of localities makes this fact at once apparent. In what follows, the lamprophyres will be regarded not as an independent group, but as a special basic modification of rocks of the normal plutonic series. This point of view is scarcely a novel one. Thus we find Hunter and Rosenbusch? describing as a new type ‘monchiquite, a camptonitic dyke-rock associated with the elwolite-syenites”’ of Brazil and Portugal, while J. F. Williams ® has given an account of such rocks and others (fourchite and onachitite) in Arkansas, and has demonstrated their genetic relations with the eleolite-syenites of that state. The varied series of rocks studied by Brégger in the Christiania district seem in several instances to run to lamprophyric modifications, and we may expect much light to be thrown on the subject in that eminent geologist’s forthcoming monograph. In endeavouring to explain the multiplicity of igneous rocks, and the evident genetic relations between widely different types, geologists have been led to speculate on the separation, by gravity or otherwise, of a large reservoir of molten magma into more acid 1 The name mica-trap evidently cannot be made to cover all the types here included. 2 Tsch. Min. Mitth. (2) vol. xi. p. 446. 3 Rep. Geol. Sury. Ark. for 1890, vol. i. A. Harker —Lamprophyres of North of England. 203 and less acid portions, which, if gravity be the controlling agent, must form upper and lower strata within the reservoir. There can be little doubt that such a hypothesis provides a vera causa for many of the phenomena. Now if we compare a more acid with a more basic type in the normal series of igneous rocks, we find certain chemical relations to hold with a high degree of generality. As the silica-percentage diminishes, the proportion of iron-oxides increases (especially at the most basic end of the series), the magnesia increases steadily, the lime increases and then falls off again, the total alkalies diminish, and the proportion of potash to soda also in general diminishes. All systematic treatment of ordinary igneous rocks which is in any degree ‘natural’ (as opposed to Linnean) is tacitly based upon these general laws. We are regarding the lamprophyres as basic modifications of various plutonic rocks, and it is easy to see that tested by the above laws they are abnormal, the exceptional characters being found in the behaviour of the alkalies. This appears on comparing the analysis of a lamprophyre with that of the plutonic rock with which it is certainly or presumably connected. Take, for instance, the biotite-granite of Durbach in the Black Forest, and the remarkable lamprophyre (the durbachite of Sauer!) which forms a marginal modification of it. The analyses give— Silica. Soda. Potash. Granitenpesenirest GligAO)r sete Sue Ai aee else 5°78 Lamprophyre ... 51°05 ...... 1°85 oes 1:24 showing that with a heavy falling off in silica the total of the two alkalies remains closely the same as in the normal rock, while the ratio of potash to soda, instead of diminishing, rises from 1:79 in the granite to 3:91 in the lamprophyre. Again, the quartz-bearing augite-syenite or akerite of Ramnas passes at its margin into a lamprophyric rock, and the figures are as follows : *— Silica. Soda. Potash. Akerite’ ....... 58°48 ...... GOD Mwecceys 3°06 Lamprophyre ... 46°40 ...... 45.8)Lessce 3°84 Here, as before, the total alkalies remain nearly the same, and the ratio of potash to soda increases from 0:56 to 0°80. The augite- minette of the Plauen’schen Grunde may fairly be compared with the syenite which it cuts through, and the results stand thus— Silica. Soda. Potash. SCHISM ereda OOESON Neto 2°44 0... 6°57 Lamprophyre ... 50°81 ...... UPON) osope 701 the total alkalies only falling from 9-01 to 8:02, and the ratio of potash to soda rising from 2°69 to 6-94. Judged by these examples, the lamprophyres would seem to be special basic modifications of their parent-rocks in which, with a greatly diminished percentage of silica, the total alkalies show little change, while potash becomes more abundant at the expense of soda. We have selected, however, cases of lamprophyres in the 1 Mitth. Grossherz. Baden Landes, vol. ii. p. 258. * Brogger, Syenitpeymatitgange, p. 49. 204 A. Harker—Lamprophyres of North of England. closest connexion with their parent-rocks ; going to greater distances, we find the total alkalies falling off, but still far in excess of the amounts proper to rocks of like silica-percentage. The relation between the two alkalies noticed above is by no means universally found in the lamprophyres (cf. those of Cornwall), but it is certainly very common and characteristic. The Shap granite has 8°22 per cent. of alkalies. In Mr. Houghton’s eight analyses of the dykes the figure varies from 7:99 to 4:52. The ratio of potash to soda in the dykes ranges from 9°51 to 0:93, and is in every case but one higher than the ratio in the granite (1:01). It is particularly high in the most basic of the lamprophyres. The chemical peculiarity of the lamprophyres, as compared with other rocks of like basicity, consists then in their relatively large content of alkalies, and in particular of potash. The mineralogical peculiarities of the rocks are, of course, simple consequences of this. The abundance of potash enables nearly all the magnesia and iron- oxides in the magma to be built up into brown mica, so that augite and hornblende occur only as minor accessories, and original free iron-ores are in very many cases not formed. A large part of the potash being taken up in the mica, it follows that the predominance of orthoclase or plagioclase among the ground-felspars will not be related in any very simple manner to the proportions of the two alkalies in the bulk-analysis, and a classification of the rocks based on the dominant species of felspar will not be a natural one. Further, in so far as any such relation holds, the plagioclase-rocks will, broadly speaking, be more acid than the orthoclase-rocks derived from a similar parent-magma. It may be noticed in the analyses of the typical European rocks that the kersantites are more acid than the minettes. Another consequence of the abundance of the basic silicate mica in the ordinary lamprophyres is that free quartz is often formed in rocks with not much more than 50 per cent. of silica. If the more ordinary types of lamprophyres are to be regarded as specialized facies of granites and syenites—the conclusion to which the foregoing remarks tend—it may be asked whether other families of plutonic rocks may have like modifications connected with them. A few peculiar rocks have been described which might possibly be considered in such a light. I would doubtfully instance Koch’s? olivine-mica rock forming a small dyke in Kaltenthal in the gabbro- district of Harzburg. This may be compared with the immediately adjacent gabbro of Ettersberg, analysed by Streng, as being con- ceivably a lamprophyre (in the extended sense) of that rock, thus :— Silica. Soda. Potash. Gabbro . 22.) 5), 50000 eee. TERI) T Tesaoac 0°83 Lamprophyre?... 34°98 ...... (Piif Sreae 5°42 Here the large quantity of potash in the second rock is very striking. In the other constituents the relation of the rock in question to the gabbro is that of an ordinary ultrabasic to a basic type. Returning to the rocks of the North of England, the question naturally arises: how did the lamprophyric magma become ab- 1 Zeits. deuts. geol. Ges. vol, xli. p. 163 (1889). A. Harker—Lamprophyres of North of England. 205 normally enriched in potash as compared with ordinary basic segre- gations? On this point some suggestions may be offered. We may imagine beneath the area where the lamprophyres are now exposed, or beneath the central part of it, a deep-seated reservoir of molten magma which was partially separated under the action of gravity, the heavier basic portion forming the lower strata. In this magma, as it cooled, the earlier products of consolidation crystallized out, the most important of these early products being the large crystals of orthoclase. It is a known fact that felspar-crystals will sink even in a basic rock-magma, and thus as the crystals formed, they must have accumulated at the bottom of the reservoir, and thus modified the total composition of the lower basic strata. The examination of the Shap granite proves that a certain portion of the quartz, the sphene, and especially the apatite crystallized out before or simultaneously with the large felspars, and these too would sink to the bottom. The felspars and quartz have been dissolved by the basic magma, but their elements would not be redistributed through the whole magma in the reservoir, except in so far as the dissolution of the crystals was concurrent with their accumulation. The process of solution seems to belong to a later stage, that of a relief of pres- sure when the injection of the dykes took place. Since the por- phyritic felspars occur plentifully in the Shap granite, we must suppose that their sinking to the bottom was finally arrested by a general consolidation of the magma, or at least a certain degree of viscosity in any part which remained molten. Subsequently to this came a partial refusion of the whole and the intrusion of the granite into its present position, closely followed by the injection of the acid dykes and sills and almost immediately the lamprophyres. The diminutive size of the corroded felspars in the latter rocks probably indicates that many others have been entirely dissolved in the containing magma, and this solution is most reasonably referred to the epoch of the injection of the dykes. It corresponds to the “resorption ” phenomena in the intratelluric hornblende and biotite of many andesites, etc., effects ascribed to the relief of pressure in the process of extravasation of the lavas. Felspar-crystals, as has been stated, are found, though as a rule sparingly, in some lam- prophyres at a considerable distance from the centre of the area; but, in view of the narrowness of many of the dykes, it seems pro- bable that their transportation has been in some measure checked by a sifting or filtering action. The above considerations may appear very speculative; but in reality, if the magma-reservoir be granted, they scarcely go beyond known facts. If some such hypothesis be found satisfactory in the area considered, it may possibly have a wider application. Certainly the association of mica-lamprophyres with porphyritic granites in numerous districts is rather striking. The porphyritic felspars, however, must not be regarded as essential. All that is requisite is that some constituent rich in alkali should crystallize out at an early stage in a magma more or less separated under the action of gravity. Such constituent may be in different cases a felspar, a 206 J. G. Goodchild—How to take Impressions of Fossils. felspathoid (leucite, sodalite, ete.), or a mica, and there may or may not be any undissolved relics of it in the lamprophyre as finally consolidated. One other remark may be made in conclusion. In rocks con- taining abnormally large proportions of potash and soda, and having at the same time plenty of alumina, it should not be surprising to find occasionally minerals richer in alkali than the felspars. Now at Cronkley, on the banks of the Tees, all the dykes contain a mineral which in thin slices shows hexagonal or quadrangular outlines, with a dark border and nucleus. The sections have no very definite action on polarized light, and seem to be more or less com- pletely converted into obscure decomposition-products. Mr. Rutley regarded the mineral as decomposed garnet, but if it occurred in a phonolite or leucitophyre it would probably be put down confidently as nosean. Without expressing an opinion on this point, I will observe that in the most easterly dyke, where the mineral in question is most abundant, there occurs another with square contour, bright blue colour, and single refraction, which I can refer to nothing but haiiyne. III.—Awn Improvep Meruop or TAKING IMPRESSIONS OF FossILs, ETC. By J. G. Goopcuttp, F.G.S8. of Her Majesty’s Geological Survey; Lecturer on Paleontology at the Heriot Watt College. ALAZONTOLOGISTS and others concerned with fossils often have need of some method of taking impressions of fossils, which shall at the same time be simple and efficacious, and shall also be of such a nature as not to cause injury of any kind to the original. Many different processes have been tried, with varied success. The following method has stood the test of application to a wide range of subjects, and has answered its purpose well in the hands of a considerable number of workers :— The only outfit required is a small roll of thin tinfoil of ordinary quality, a small plate-brush, neither too hard nor too soft, a bottle of shellac varnish, and some paraffine wax, with a night light or some such means for melting it. If the fossil is not in too high relief, say a fossil fish, or such a plant as a Coal-measure fern, all that is needed is to cut a piece of foil rather larger than the specimen, then to press it gently, with the finger tips at first, into all the larger depressions, beginning at the middle and working outwards towards the edge all round. Then, keeping the fingers extended over the impression, go over the whole thing with the plate-brush, using it as gently as possible, and with only a very slight lateral movement. After a few seconds treatment of this kind an almost exact counterfeit of the fossil will appear— even some of the very finest sculpturings being distinctly visible on the upper surface of the foil. When that stage is reached, the foil should be lifted very gently at each corner so as to free it from any projecting or undercut points. Herein lies the special value of the tinfoil process, inasmuch as this material does not enter the undercut parts as modelling wax, J. G. Goodchild—How to take Impressions of Fossils. 207 gutta percha, etc., are apt to do; consequently when the tinfoil is withdrawn it never drags away part of the fossil. When the foil is loosened so that it will lift off easily, it should be gently pressed back again with the brush so as to make it resume its proper shape. Then, if the subject is tolerably flat, and no holes have been torn in the foil, it may be lifted off at once. To fix it, the most important part of the process, it will generally suffice to pour on to the impressed, or under, side, sufficient shellac varnish (which should be of a consistence between that of cream and that of treacle) to float the whole surface. This should not be distributed by means of a brush, but by simply turning the impression about until the surface is covered by the varnish. In a few minutes this will be dry enough to lay by. A second coating, later on, will render it quite hard enough to stand ordinary handling without any risk of altering its shape. Should the fossil be in somewhat higher relief, so that a few holes are torn in the foil, the best mode of treatment is to go over the upper surface of the “counterfeit” with a thin coat of melted paraffine while it is on the original. The wax chills at once into a firm mass, and the foil may be lifted off with ease. Then the back is floated with varnish as before. When this is set, all that is necessary to do is to put the foil into water sufficiently hot to melt the paraffine, which at once floats off, leaving the foil quite bright, as before. In the case of objects in very high relief more care is, of course, required ; but the process answers very well even then. Thanks to the courtesy of Dr. Traquair, I have been enabled to make tinfoil counterfeits of a large number of fossils from the collection in the Edinburgh Museum of Science and Art, many of them in high relief, by this process; and, with a little management, have been able to make them retain the form of the original perfectly, by coating the inside of the impression with cotton-wool, and flooding this with varnish as before. In some respects impressions made by this process are even better than the originals; for the metallic lustre of the tinfoil causes the light to be reflected from the salient parts of the copies much more strongly than from the originals. Indeed, when the part of the foil representing the matrix is painted a dead black, I find it much easier to draw from the foil impressions than from the originals. Another advantage presented by this method is that any number of copies can be made in a very short space of time; and in lecturing on Paleontology in Edinburgh, I am able in the majority of cases to place in the hands of each student a reliable copy of the fossil I am describing, and in this way he is able to make more satisfactory progress than would otherwise be possible. Lastly, as Curator of a Collection embracing nearly twenty thousand specimens of fossils, I am occasionally called upon to lend out specimens for description. In all such cases my plan is to take a careful tinfoil counterfeit of the original before it goes out, and this, with the register entry, places the exact nature of the loan on ‘record in a manner that leaves nothing to be desired. 208 C. Davison—On Earthquake-Sounds. IV.—On toe Nature anp OrIGiIn or HARTHQUAKE-SOUNDS. By Cuarues Davison, M.A. ; Mathematical Master at King Edward’s High School, Birmingham. HE sound-phenomena accompanying earthquakes have not often been made the subject of special investigation; and, con- sequently, their value and significance may have been somewhat underrated. I believe that much remains to be done, that many _ Observations must yet be made, before the problem of their origin can be regarded as completely solved; but the facts already known seem to me sufficient to show that the inquiry is one full of interest and worthy of development beyond that here attempted. Nature oF EartHQquakeE-Sounpbs. 1. Character of the Sound.—The sound is sometimes of so unusual a character that it is difficult to describe it exactly, but generally it more or less resembles one of the following: (1) Thunder—either a clap or a prolonged peal, the rolling of distant thunder, or thunder when it dies away as echoes among mountains. (2) The rumbling of passing carriages, wagons, etc.—driven rapidly over a hard road, over pavement, stones, a wooden or stone bridge, or under a gate- way, a heavy traction-engine passing, a couch or heavy chair dragged across the floor of a room above, a train rapidly approaching or rushing through a station, the jerking of a train brought suddenly to rest, the rumbling of wagons laden with planks, sina: or heavy casks. (3) The firing of cannon—either one or several in quick succession, a heavy and well-sustained fire of artillery, a distant cannonade. (4) An explosion—a blast in a quarry, a colliery explosion, the blowing-up of a magazine or powder-mine. (5) The fall of heavy bodies—a cartload of stones suddenly emptied, a heap of rubbish shot down, a large quantity of shingle poured on to a house-roof from a great height, the fall of houses, snow sliding down the roof of a house and falling on the ground, an avalanche of snow, the fall of heavy furniture, a signal-post or a heavy mattrass, a cannon-ball rolling downstairs. (6) Wind—a blast or sudden gust, the roar of wind in a storm, wind among trees, the suppressed roaring of wind entering a gorge, a chimney on fire. (7) Miscel- laneous—a hissing noise Tee that of red-hot iron plunged into water, the rushing of ‘water, the cracking of a wall, a door violently slammed, the breaking of glass, a horse loose in its stall, the muffled rat-a-plan of heavy side-drums, a burst of applause in a room over- head like what newspapers call “loud and prolonged cheering.” * In a few cases (the breaking of glass, for example, or the rustling 1 This list, by no means an exhaustive one, is compiled from 389 accounts, obtained from the third part of Mallet’s Catalogue of Recorded Earthquakes (Brit. Assoc. Rep. 1854), Meldola and White’s East Anglian Earthquake of 1884, and the notes communicated to me by correspondents during my study of the British earthquakes of the last three years. Out of the above number, comparisons are made to thunder in 97 cases, to the passing of carriages, -ete., in 130, the firing of cannon in 43, explosions in 45, the fall of heavy bodies in as, wind in ile and to various sounds under the last heading i in 14 cases. C. Davison—On Earthquake- Sounds, 209 of wind among trees), the sound is a comparatively high one; but, most frequently, it is a deep rumbling noise, sometimes perhaps not very much above the lower limit of audibility. 2. Variations in Intensity and Pitch—The frequent use of the words “rolling” and “rumbling” in describing earthquake-sounds, as well as comparisons to thunder, etc., shows that the sounds do vary both in intensity and pitch. On a few rare occasions, the sound is said to begin or end abruptly, the intensity being at, or not far from, its maximum. But most frequently, almost invariably I believe when the observation is complete, the sound begins faintly, becomes continually louder, and then gradually dies away. As might be expected, this change in intensity is most marked in the immediate neighbourhood of the epicentrum ; near the limits of the sound-area it is hardly perceptible, and the sound there resembles closely the low roll of distant thunder. Records of variation in pitch are far from numerous. The following may be given as examples: (1) 1791, Nov. 27, Lisbon. Two shocks, one five minutes after the other. The second and more violent shock “was attended with a hissing noise like that of red-hot iron quenched in water, and ended with an explosion like the report of cannon.”! (2) 1884, April 22, Essex. At Summerhill, about 14 miles N.W. of Colchester, “suddenly a jingling noise was heard, which developed rapidly into a deep underground rolling noise.’ The beginning of the sound seems to have preceded the beginning of the shock, and, at two other places in the neighbour- hood, this was the case.? (3) 1890, Nov. 15, Beauly, near Inverness. “There was a great noise, as if huge quantities of shingle were being poured upon the house-roof from a considerable height, the sound deepening to that of heavy artillery.” The evidence is too scanty to support any certain conclusion, but it seems to afford some grounds for believing that the sound becomes deeper as it increases in intensity ; in other words, that the period of vibration increases with the amplitude. RELATIONS OF THE SOUND TO THE SHOOK. 1. With regard to Time.—Professor Milne, in an interesting ‘“‘Note on the Sound Phenomena of Earthquakes,’*® remarks that in the majority of cases, the sound precedes the shock rather than follows it; and he conjectures that the sound, when it does follow the shock, may be an independent phenomenon.* In order to determine the relative frequency of the different cases, I examined the accounts given in the third part of Mallet’s “ Catalogue of Recorded Earthquakes ” (7.e. those occurring between August 26, 1784, and the end of 1842), in which the time-relation 1 Mallet, Catalocue of Recorded Earthquakes, Brit. Assoc. Rep. 1850, p. 30. 2 Meldola and White, East Anglian Karthquake of 1884, pp. 55, 57, 58. 3 Japan Seismol. Sqe. Trans. vol. xii. pp. 538-62. 4 There can be no doubt that this is frequently the case. See, for instance, M. Boussingault’s paper, ‘‘ Sur les détonations constatées pendant les tremblements de terre,’’? Comptes Rendus (July 18, 1881), vol. 93, pp. 105-6; also Humboldt’s Cosmos (Bohn’s edition), vol. i. pp. 203-4, DECADE 1II.—VOL. IX.—NO. V. 14 210 C. Davison—On Earthquake-Sounds. of the sound to the shock is definitely stated. There are in all 425 records. The sound is said to have : Preceded the shock in ads aoe vas 100 cases. Accompanied or attended iti in aac ae a 307 4, Followed it in a Bas sah ihe Dor Preceded and accompanied itin ... a S00 Za Accompanied and followed it in ... se op Preceded, accompanied and followed it in . dee Sas It must be admitted that the phrase “ deh sinbanied ” or “attended,” singly, is a very vague one. Asa general rule, it only means that the sound was heard at about the same time that the shock was felt ; hardly ever, perhaps, that the beginning and end of both sound and shock were coincident. It cannot, then, be taken to exclude cases in which the sound may have overlapped the shock at either end or both. The meaning of the terms “preceded” and “followed” is less ambiguous, though not free from doubt. But, so far as regards the earthquakes recorded by Mallet, it is clear that the beginning of the sound must have preceded that of the sensible shock much more frequently than the end of the sound followed that of the shock. Turning, however, from these earthquakes, which are, as a rule, of considerable intensity, to shocks of slight intensity and short duration—shocks, for example, like those generally felt in this country—it will be found that the comparative rarity of subsequent sounds is not so strongly marked. In studying the Inverness earth- quake of November 15, 1890, I received definite replies to the question on the time-relations of the shock and sound from 64 places, with the following results.1_ The sound is said to have Preceded the shock at 366 is se ae 20 places. Accompanied TUE oe oe 4a aEe ae 2000 ee Followed it at ees 3 WA ee Preceded and accompanied it aby is2 ey ee Bie igs Accompanied and followed it at... : ant nen Preceded, accompanied and followed it at.. 508 ne In the other British earthquakes iN I have studied the obser- vations on this point are less numerous, but they are sufficient to show that, in certain parts of the disturbed area at any rate, the sound frequently continues to be heard after the close of the sensible shock. 2. With regard to the Maximum Intensity of the Shock and Sound.— It has been already remarked that, in British earthquakes, the sound increases in intensity, to a maximum, and then dies away. Now, it appears, from a large number of observations, that 7 is just at the moment when the sound is loudest that the principal vibrations are felt. This fact was noticed fifty years ago by Mr. David Milne (after- wards Milne-Home) in a valuable series of papers on the earthquakes of this country. In summarizing their principal features, he remarks that there appear to be two distinct sensations, a tremor and a violent blow or concussion, the latter known in Comrie and the neighbour- hood as the “thud.” “The tremulous or trembling motion,” he says, 1 Quart. Journ. Geol. Soc. 1891, p. 6238. C. Davison—On Earthquake- Sounds. Alu ‘is always perceived. When the blow occurs it is generally in the midst of the tremors, and at the moment that they are the most intense, and accompanied with the loudest noise.” * In studying the more recent British earthquakes, I have received many observations on this point, of which the following examples may be given: (1) The epicentrum of the Kintyre earthquake of July 24, 1890, was a few miles from Clachan: ‘at which place the shock began with a series of slight tremors lasting for twenty seconds. These tremors gradually. “increased in intensity until a vibration was felt like what would be caused by a heavy stone falling from a very great height,” and this vibration, again, was followed by tremors lasting for five seconds. During the whole time of the tremulous motion a sound was heard like the crashing of falling stones, and, coincidently with the principal vibration, a dull “thud” as of a suppressed explosion.? (2) In nine different accounts of the Inverness earthquake of November 15, 1890, a similar phenomenon was described. At Boleskine, for instance, an observer “heard a sound as if a heavy train was approaching,. . . it gradually got louder and louder until it seemed to go right through the house, shaking the pictures and china ornaments on the walls.” (8) Still more to the point, perhaps, is a remark made by an observer at Boscastle (Cornwall) of the earthquake felt there on March 26, 1891. This earthquake consisted of two distinct shocks separated by an interval of a few seconds. The sound was loudest just at the times when the shocks were felt, and continued, _ though more faintly, during the whole of the interval between them. A. Rewations oF THE Sounp To THE DistuRBED ARBA. 1. Variations in the Nature of the Sound and in its Relation to the Shock throughout the Disturbed Area.—In every earthquake, of which sufficiently numerous observations have been made, the sounds vary greatly throughout the disturbed area, not only in intensity, but also in character, duration and relation to the shock. In the great Neapolitan earthquake of 1857, so ably studied by the late Mr. Mallet, the sounds were heard over an area roughly elliptical in form, its longer axis being directed about N.W. and 8.H. All the observers towards the northern and southern extremities of this area described the sound as ‘“‘a low, grating, heavy, sighing rush, of twenty to sixty seconds in duration, some thinking that it was also a sort of rumbling sound, but with none, a distinct, well- defined explosion, or several in succession.” Those ‘‘who were situated towards the middle of the sound-area, and towards its east and west boundaries, on the contrary, very generally described the sound, as something of the same character as to tone, but with more rumbling . . . . and as shorter and more abrupt both in commence- ment and ending, and in duration.” * The Inverness earthquake of November 15, 1890, was, I believe, 1 Edinburgh New Phil. Journ. (1841), vol. xxxi. p. 261. 2 Geox. Mae. (1891), Vol. VIII. pp. 453-4. 5 «The Neapolitan Earthquake of 1857,’ vol. ii. p. 288. 212 C. Davison—On Earthquake- Sounds. caused by the slip of a fault running approximately north-east and south-west, and hading to the north-west, the slip extending probably over a horizontal distance of several miles, and being greatest towards the south-west. Now, ‘the 25 places at which the sound preceded, or preceded and accompanied, the shock, though not confined to any one part of the disturbed area, are mostly situated in the district north-east of the epicentrum,” while five of the six places at which the sound followed, or accompanied and followed, the shock are “either south-west of the epicentrum, or close to it on the north-west side, 7.e. just where the intensity is greatest.” 2. The Hxtent of the Sound-area is independent of that of the Disturbed Area.—Humboldt, in his ‘‘Cosmos,” remarks that “the intensity of the hollow noise which generally accompanies an earth- quake does not increase in the same degree as the force of the oscillations ;”’! and it has also been observed that, in very violent earthquakes, the sounds are confined to a comparatively small area in the neighbourhood of the epicentrum. The Neapolitan earthquake of 1857, for instance, disturbed the whole of the Italian peninsula south of lat. 42°, being felt nearly as far as Rome, while the sounds were only heard within an area containing 3300 square miles imme- diately surrounding the epicentrum. The slighter shocks of this country also afford good examples. In the East Cornwall earthquake of October 7, 1889, and the Inverness earthquake of November 15, 1890, the sounds were heard at nearly all the places where the shocks were felt; though it is of course possible that in these cases the coincidence of the sound-area and the disturbed area may have been apparent rather than real. The Edinburgh earthquake of January 18, 1889, disturbed an elliptical area, about 80 miles from north to south, and 265 miles from east to west; the length of the sound-area was about 25 miles from north to south, its breadth could not be exactly determined. The dis- turbed area of the Lancashire earthquake of February 10, 1889, was approximately circular, being 56 miles from north to south and 54 miles from east to west; the sound-area was very nearly circular and 29 miles in diameter. These examples are sufficient to show that the extent of the sound- area bears no constant relation to that of the disturbed area. As a general rule, we may say that, the more intense the earthquake, the less is the ratio of the extent of the sound-area to that of the disturbed area; but this is by no means always true. The limiting case, in which sounds are heard without any perceptible shock, is one of which records are frequent. One of the most remarkable is that described by Humboldt in his ‘* Cosmos,” where he refers to the subterranean thunderings (bramidos y truenos subterraneos) of Guanaxuato on the Mexican plateau. ‘‘ The noise,” he says, “began about midnight, on the 9th of January, 1784, and continued for a month..... From the 15th to the 16th of January, it seemed to the inhabitants as if heavy clouds lay beneath their feet from which issued alternate slow rolling sounds and short 1 Vol. i. p. 203, C. Davison—On Earthquake-Sounds. 218 quick claps of thunder. The noise abated as gradually as it had begun. It was limited to a small space, and was not heard in a basaltic district at the distance of a few miles.” ‘‘ Neither on the surface of the earth,” he adds, ‘‘ nor in mines 1600 feet in depth was the slightest shock to be perceived.” ? The following accounts throw additional light on the subject : (1) At Hast Haddam, Conn., U.S.A., on May 16, 1791, at 8 p.m., two shocks were felt in quick succession, of which the first was the more violent. Soon after, these were followed by a third and slighter shock, and this, again, by nearly one hundred feebler shocks throughout the night. “Subterranean noises are constantly heard at Kast Haddam, whence its Indian name, Morehemodus, or the place of noises. After this shock, both noises and shocks became less frequent.” In several cases noises were heard about this time unaccompanied by any shock. (2) In Piedmont, on April 2, 1508, at 5.43 p.m., an earthquake of intensity VIII., according to the Rossi-Forel scale, was felt, its centre of disturbance having apparently been at Pignerol. This was followed by a large number of slighter shocks (Mallet records about 300) until July, 1809, after which they became less frequent. At Barga, La Tour and other places in the district, subterranean noises were often heard without any accompanying shock. (8) In the island of Meleda, in the Adriatic, noises were heard during a still longer period, from March, 1822, to February, 1825. Mallet remarks that they ‘do not seem to have been accompanied by any true earthquake shocks, or, at least, any such felt were extremely slight;” but, according to Humboldt, they were “occasionally accompanied by shocks.” (4) At St. Jean-de-Maurienne (in Savoy) and the surrounding ‘district, 49 principal shocks were felt between October 4 and December 28, 18589, ‘‘and many more indistinct ones which were not recorded. .... They were generally preceded or accompanied by subterranean noise, and sometimes this noise was heard without any sensible shock.” (5) On October 3, 1839, a remarkable series of shocks commenced at Comrie, in Perthshire. ‘The shocks were in general very slight, but sometimes rather severe, and were generally accompanied by subterranean noises, variously described as like distant thunder, the reports of artillery, the sound of a rushing wind, etc. The noise .... was often heard without any sensible shock at the time.” It would appear from these examples that subterranean sounds without any accompanying earthquake especially characterise those districts where slight shocks are very frequentiy felt, as if the sounds and shocks were manifestations, differing only in degree and the method in which we perceive them, of one and the same class of phenomena.’ 1 Vol. i. p. 205-6. * Mallets Catalogue of Recorded Earthquakes, Brit. Assoc. Rep. 1854, pp. 28, 31, 68-84, 138, 152, 162, 166, 288, 290; Humboldt’s Cosmos, vol. i. p. 205, foot- note. Possibly also of seismic origin are ‘the phenomena known as the Bariséll "Guns, *‘sounds resembling the fire of ‘heavy cannon at a distance, which are heard at various points in the Delta of the Ganges and Brahmaputra, and in the hills to the north of it’’ (Brit. Assoc. Rep. 1891). 214 C. Davison—On Earthquake-Sounds. On the other hand, there is the well-known instance mentioned by Humboldt, of no sounds at all being heard during a very violent earthquake. ‘I have ascertained with certainty,” he says, “that the great shock of the earthquake of Riobamba (4th February, 1797) —one of the most fearful phenomena recorded in the physical history of our planet—was not accompanied by any noise whatever ;” and again, later on, speaking of the same shock, he says: “The earth- quake itself was neither accompanied nor announced by any sub- terranean noise.” ' This is the only example I know of, and it is obvious that a satisfactory theory of earthquake-sounds must account for the commonness of the one extreme case and the rarity of the other. B. 3. The Sound-area is not necessarily concentric with the Disturbed Area. — The excentricity of the sound-area is one of the most important phenomena connected with earthquake-sounds, and it was the recognition of this in the cases of the Edinburgh and Lancashire earthquakes of 1889 that led to the theory explained in the latter part of this paper. I will here give a short outline of the principal facts, referring for a fuller description of the sound and other phenomena of these shocks to my paper, ‘“‘On the British Harth- quakes of 1889.” ? Edinburgh earthquake of January 18, 1889.—The epicentrum is situated about 3 miles W. 42° S. of Balerno, and the centre of the sound-area about 24 miles to the south or south-east of the epi- centrum. Both points lie on the north-west or downthrow side of the first of the great faults to the north-west of the axis of the Pentlands; and it is very probable that the earthquake was due to the impulsive friction arising from a slight slip of this fanlt at a spot not far from the middle of its course as laid down upon the Survey map, a slip which increased the throw of the fault. The centre of intensity of the seismic focus was probably at a point on the fault at the depth of about eight miles. The simple character and short duration of the earthquake show that the horizontal length of the area over which the slip took place was not great, perhaps not more than a mile. Now, the centre of the sound-area is close to the line where the fault meets the surface, nearer to it by abont 2+ miles than the epicentrum; and this shows that the sound- vibrations must have chiefly proceeded from a part of the focus nearer the surface than did the vibrations of larger amplitude which caused the shock itself. Lancashire earthquake of February 10, 1889.—The epicentrum of this earthquake is about two miles N.N.E. of Bolton, and on the north-east or downthrow side of the great Irwell valley fault. About 34 miles $.8.W. of the epicentrum, and apparently at a short 1 Cosmos, vol. i. p. 203, and vol. v. p. 172. Mallet, in his Catalogue, occasion- ally indicates an earthquake as having been unaccompanied by sound, but it is not certain that his observations were drawn from a large part of the disturbed area. Prof. Milne states that sounds are not often heard during the Japanese earthquakes, but many of these earthquakes originate under the sea, and the places where they are observed in Japan may possibly be outside the sound-areas. * Grou. Mac. (1891), Decade III. Vol. VIII. pp. 57, 306, 364, and 450. _C. Davison—On Earthquake- Sounds. 215 distance on the upthrow side of the same fault, is the centre of the sound-area; but its position cannot be determined with any great accuracy, for I know of no places where the sound was certainly not heard. The evidence obtained is, I believe, sufficient to show that the earthquake was caused by a slip of the fault referred to, the slip being one that increased its throw; that the centre of intensity of the seismic focus was at a depth of about 3? miles; that the horizontal length of the area over which the slip took place was short, perhaps less than a mile. Remembering the uncertainty in the position of the centre of the sound-area, I think we may infer that, in this earthquake also, the sound-vibrations originated at a part of the fault nearer the surface than the centre of the seismic focus. C. OriciIn oF EarTHQUuAKE-SouNDS. Within the last few years, the numerous seismographic records made in Japan by Profs. Milne, Ewing and Sekiya have thrown considerable light on the nature of earthquake-vibrations. It is chiefly, however, that part of the series including, and bordering on, the sensible vibrations which has been studied: for, as Prof. Milne remarks, ‘‘many earthquakes, like the solar spectrum, have extremities which are difficult to investigate.” The records referred to show that earthquakes usually begin with a series of very small and very rapid tremors, from six to eight occurring every second ; that, after lasting perhaps for many seconds, they become less rapid, and then, without any break of continuity, follow the sensible vibrations of lar ger amplitude and longer period, at the rate of about three to five per second. One or more of these, attaining an amplitude still greater and having a period of one or two seconds each, constitute what are generally known as the principal shock or shocks. The earthquake closes with vibrations of smaller amplitude, but “which are so long in period, that the pointers and steady points of our seismographs do not give a relative movement, but follow these back and forth movements as a whole, and no record is obtained.” On the other hand, they fail to register the commencing tremors of the earthquake on account of their ex- tremely small amplitude. Now, for the part of the series preceding and including ihe principal shocks, the period of the vibrations increases with the amplitude; and it is therefore not unreasonable to conclude, as Prof. Milne has done, that the first tremors recorded are ‘the con- tinuation of still smaller and more rapid movements, which on account of want of sufficient multiplication in our instruments have never yet been rendered visible.” And it is to these supposed very rapid vibrations, which form the front portion of an advancing earth- quake, that Prof. Milne attributes the origin of the earthquake-sounds. Summing up, he says: “The majority of earthquake-sounds are produced by short period surface vibrations of the earth and these vibrations are portions of and continuous with the earthquake that accompanies the sound.” ! 1 Japan Seismal Soc. Trans. vol. xii. pp. 107 and 60. 216 C. Davison— On Earthquake-Sounds. Throughout the remainder of this paper, I shall conclude that Prof. Milne’s observations do, as he suggests, imply the existence of preliminary vibrations short enough in period to give rise to the phenomena of earthquake-sounds; and I shall endeavour now to show how these vibrations originate, and at the same time to account thereby for the different sound-phenomena described above. To give definiteness to the theory, I shall take the case of an earthquake produced, as I believe most non-volcanic earthquakes are produced, by the friction due to the slipping across one another of the two rock-surfaces of a fault. The seismic focus, or slip-area, may be of very considerable dimensions, sometimes fifty miles or more in length. The intensity of a shock does not, however, depend so much on the size of a slip-area as on the maximum amount and short duration of the slip. Now, it is evident that the amount of the slip must vary greatly throughout the slip-area, but it will be sufficient to consider only the simplest case, that in which the amount of slip is a maximum in a certain central region, and diminishes gradually until it is zero along the margin of the seismic focus; though the faces of a fault not being smooth planes, there will probably be several or many such regions of maximum slip.! Now, since up to a certain point the period of a vibration increases with its amplitude, and since the initial amplitude of the vibrations must depend on the amount of slip producing them, there will, from all parts of the slip-area considered, proceed vibrations varying, not only in amplitude, but also in period; and along the borders of the slip-area, where the fault-slip dies away, these vibrations may be small enough, and consequently rapid enough, to produce the sensation of sound. 1 imagine, then, that the sound-phenomena ac- companying earthquakes are produced by the minute vibrations coming chiefly from the upper and lateral margins of the slip-area. For brevity, I will give the name of the “ sound-focus” to that part of the slip-area or seismic focus from which the sound- vibrations come. The boundary-line between the sound-focus and the rest of the seismic focus is not a definite line. Its position varies with the lower limit of audibility of each observer, so that at exactly the same spot two observers might differently estimate the duration of the sound. But, neglecting for our present purpose this personal equation in the observers, it is evident that the position of the boundary-line referred to depends only on the position of the points on the slip-area at which the amount of slip is just small enough to produce vibrations which may be heard, that it is independent of the maximum amount of slip within the seismic focus. Now, other conditions being the same, the dimensions of the sound-area are determined by the intensity of the vibrations which are just per- ceptible as sound, and those of the disturbed area by the maximum 1 The rumbling or rolling character of the sound, though arising partly no doubt from interference, may also in part be due to the existence of several regions of maximum slip. C. Davison—On Earthquake- Sounds. 217 intensity of the initial earthquake-vibrations; and therefore the extent of the sound-area must be independent of that of the disturbed area. It is possible that from the lower margin of the slip-area sound- vibrations may proceed; but, so far as regards the sounds heard at the surface, the vibrations proceeding from the upper and lateral margins must be most perceptible. The centre of intensity of the sound-focus must therefore, as a rule, be within the upper margin of the seismic focus, i.e. the sound-area is not concentric with the disturbed area, and the centre of the former is nearer to the fault- line than the centre of the latter. Throughout the greater part of the sound-area, the vibrations first perceived must be those from the upper or lateral margin of the seismic focus, i.e. the beginning of the sound must generally precede the beginning of the shock. There will, however, be a small part of the disturbed area, that immediately surrounding the point where the normal to the slip-area meets the surface, where the shock may be felt first: unless, indeed, the fault-slip does not take place instantaneously, but, commencing very slowly, initiates a series of short-period vibrations frem the whole slip-area before the true earthquake vibrations are produced. In this case, however, the excentricity of the sound-area would be hardly perceptible. At most places within the sound-area, then, the sound will be first heard, due to vibrations proceeding from the nearer lateral margin of the seismic focus. The sound will become gradually louder and deeper until its intensity is a maximum, the vibrations then coming from the boundary-line between the sound-focus and the rest of the seismic focus. Soon after this, the sensible shock will be felt, due to vibrations proceeding from that part of the focus where the amount of slip is greatest, the sound continuing for all or part of the time, owing to the arrival of vibrations from the upper margin of the slip-area. And, lastly, after the sensible shock ceases to be felt, will be heard the sound coming from the further lateral margin of the slip-area, provided that margin be not too distant, the sound becoming higher as it dies away. In the neighbourhood of the boundary of the sound-area, the sound-vibrations from the further lateral margin of the seismic focus will be imperceptible, and the sound will be heard only preceding, or preceding and accompanying, the shock; and this may in part account for the comparative rarity of the records of the subsequent sound-phenomena. Again, in most British shocks, the part of the focus from which the sensible vibrations come is of small magnitude, so that only one or two principal vibrations are produced, and these are feli just at the time when the sound is loudest. If the sound-vibrations first or last perceived be those which come from the boundary between the sound-focus and the rest of the seismic focus, the sound will begin or end abruptly. But observa- tions of such a phenomenon must be rare. The different relations between the dimensions of the sound-area 218 W. M..Hutchings—Ash-siates of the Lake-District. and the disturbed area may be attributed to variations in the amount of slip throughout the seismic focus. (1) If the amount of slip be everywhere very small, the sound-focus may occupy the whole of the slip-area, and thus sound may be the only phenomenon per- ceptible at the surface to the unaided senses. his seems to have been frequently the case amongst the series of small slips which produced the numerous slight shocks at Comrie, Pignerol, and else- where. (2) If the sound-focus occupy nearly the whole of the slip-area, the amount of slip in the rest of it being small, but still great enough to produce a slight shock, then the sound-area and the disturbed area might. be approximately co-extensive, or the sound- area might in places entirely overlap the disturbed area. (3) But very frequently, especially in the more pronounced seismic areas, the maximum amount of slip within the seismic focus will be so great that the disturbed area will be large compared with the sound-area, and, in severe earthquakes, will extend far beyond it. (4) Lastly, the slip might take place suddenly, and its amount be so great, that the sound-focus might be confined to the lateral margins of the slip-area. The slip would then extend up to the surface of the earth, and, if great enough, might be traceable there as a difference of elevation on the two sides of the fault-line; the sound-area would consist of two detached portions at some distance from the region of maximum disturbance, and the sounds con- sequently might escape observation and record. But while earthquakes of such extreme intensity are very unusual, very slight slips must frequently take place; so that earthquake- sounds without an accompanying shock should be of far more common occurrence than earthquakes without attendant sounds. V.—Nortes on THE ASH-SLATES AND OTHER Rocks oF THE LAKE District. By W. Maynarp Hvrcurnes, Esq. (Concluded from page 161.) AKING the other and coarser constituents of such slates as are not wholly made up of the fine “base,’—the constituents which may be spoken of as “ porphyritic,’””—the lapilli vary very greatly in number and distinctness. In a large part of the roofing-slates they are either no longer discernible at all or are so exceedingly faded and blurred as to be just barely recognizable, often as patches altered to chlorite, or chlorite and calcite, in which the felspar-laths of the original andesitic ground-mass may still be seen comparatively little altered. In cases where there is reason to suppose that the lapilli were largely of more basic nature, this almost complete alteration of them is observed, as might naturally be expected. In other cases the crushing and rolling-out of the rock has sufficed to obliterate all traces of original fragments of whatever sort. On the other hand, there are many slates in which lapilli, in great abundance, are still so perfectly preserved as to exceed in freshness W. W. Hutchings—Ash-slates of the Lake-District. 219 most of the andesites, etc., which can be collected in situ. Even in some cases where the slates are most highly cleaved, and the “base” and some of the other constituents, as chlorite and calcite, are drawn into streaks often flowing round the still angular lapilli, these latter have almost wholly escaped mechanical damage. In these cases of strikingly good preservation basic lapilli are absent. The slates from Mosedale quarry have already been mentioned as offering beautiful examples of well-preserved lapilli, and equally good ones are seen at other places. It is to be noted that though rhyolite is exposed in comparatively few localities in the district, it is more or less represented in almost every specimen of slate in which the lapilli are still distinct. This frequent occurrence of rhyolite in the fragmental rocks of the Lake District has been noticed also by Harker and Marr (On the Shap Granite, etc., Quart. Journ. Geol. Soc. vol. xlviil. 1891). In addition to volcanic lapilli, many of the slates and tuffs show also the presence of fragments of sedimentary rocks, presumably broken through and ejected by the explosive eruptions. I have formerly recorded (Grou. Mac. 1891, p. 462) the occurrence of such a mixed volcanic and sedimentary material in a tuff at Falcon Crag. It may be observed again, though in less marked degree, in rocks from Honister Crag, both roofing-slates and coarser tuffs and breccias, in which fragments of grits and gritty slates occur ; and in material from several other localities careful search shows that fragments of ordinary sedimentary slates are present, recognizable, among other things, by the rutile-needles contained in them. In many cases these fragments are crushed and drawn out so as to be almost incorporated beyond recognition with the volcanic material, and it is most likely that, as might be expected, a large proportion of the ashes and tuffs of the district contain more or less of the sedimentary strata underlying them. Angular clastic grains of quartz, some of good size, are also tolerably frequent, suggesting a derivation from some coarse-grained acid rock, probably granite. None of the finer-grained slates, so far as my observations go, contain any trace of augite or other ferro-magnesian mineral. These are now represented entirely by chlorite, calcite, and some epidote. Chlorite is always present in large quantity in the coarser slates, as patches and rolled-out streaks, as well as in the minutely-felted form in the base. Calcite is exceedingly abundant, disseminated as small grains down to fine dust, or as larger grains and crystals. ‘These frequently contain fluid-cavities with bubbles, showing the con- ditions of pressure, etc., under which this calcite was deposited. In many slates the calcite is so plentiful that it very nearly obliterates everything else except the chlorite, the rolled-out mixture of the two appearing at first sight to make up nearly the entire rock. It is interesting to note that though the mineral changes which have taken place in the finely-powdered ash-material of these slates are in a most important point similar to those which have occurred in the deposits to which we owe our fireclays and shales and most 220 3 W. MM. Hutchings—Ash-slates of the Lake District. of our sedimentary slates, inasmuch as a very large amount of new mica has been formed, yet in the matter of the titanic acid con- tained in the material acted upon the result is very different. It is beyond question that the volcanic rocks of the Lake District contain a quite considerable amount of titanic acid, though it has not been determined in the analyses made.’ Probably a portion was combined in the form of sphene, but most likely the greater part was contained in the augitiec minerals. In the weathered and much altered andesites as we now have them, secondary sphene is one of the most constant constituents, in granular form and also as little clusters and groups of crystals, often evenly disseminated throughout the rock. This sphene has probably been mainly formed during the decay of the augites and the basic portion of the ground-masses. At Shap, under the influence of contact- action, the sphene of the andesites and ashes appears to have been re-dissolved and re-deposited, one of the most striking features of the altered rocks being the considerable number of large grains of deep-coloured, very dichroic sphene which have been formed, wholly different from anything seen in the rocks at a distance from the contact. Sometimes these large grains of sphene occur in cavities in such relationship to quartz and other infiltrated matter as to leave no room for doubt as to the manner of their deposition. Notwithstanding this considerable amount of titanic acid, how- ever, the slates resulting from the chemical and mechanical altera- tion of the andesitic ashes do not ever show the rutile-needles so universally characteristic of the sedimentary clays and slates. From a considerable observation of these rocks from all over the district I am able to state that rutile in that form is never noticed in them, except in those cases in which it is explained by included sedimen- tary matter originally containing it. To the best of my belief, based on much study of this special point, it may be pretty safely said that rutile in the form we know as “ slate-needles,’—a form so very characteristic and always recognizable,—occurs only as the result of decomposition, under certain conditions, of deposits partially consisting of biotite. As I have noted in a former paper (GEOL. 1 Kyven now that the general presence of titanic acid in rocks is more fully known than formerly, it is very rarely determined by analysts. This arises to some extent from the fact that its non-determination does not affect the total addition of the analysis, as in the ordinary course of the estimations it is weighed partly with the silica and partly with some of the bases. But the non-determination is more largely due to the fact that the exact quantitative serparation of titanic acid is a very tedious and difficult operation. In the ‘‘ American Journal of Science’’ for December, 1891, is an interesting paper by Mr. F. P. Dunnington, “ On the Distribution of Titanie Oxide upon the Surface of the Earth,’’ in which he gives the results of 72 determinations on soils from various parts of the world, as well as on a few rocks. The universal diffusion of this oxide in appreciable quantity is fully demonstrated. ‘These many determin- ations were not made by Mr. Dunnington in the ordinary tedious gravimetric manner, but by a rapid calorimetric process which is described in the paper. It is to be supposed that this method has been fully checked and proved to be reliable. That being so, the determination of titanic acid in our rocks and minerals ought to become the rule instead of the exception, since an easy and rapid method is available for it. W. M. Hutchings—Ash-slates of the Lake-District. 221 Mae. 1891, p. 587), biotite appears to be practically absent from the rocks of the Borrowdale series.’ The titanic acid in these slates takes other forms. It largely occurs, as in the altered andesites, as disseminated granules and small crystals of secondary sphene. Slates showing this, to the exclusion of any other form of occurrence, are exemplified in the quarries at the top of Kentmere Valley, and on the other side of the same ridge in Troutbeck Valley. Rutile occurs, though on the whole sparingly, in the form of blunt crystals and grains lining cavities, the central parts of such cavities being usually filled in with quartz, or calcite, or both. Another and more widely-spread form of occurrence is as anatase in small double pyramids, with or without the prism-band, exactly as in the altered Coniston Flags at Shap.? These anatase crystals were first noticed in a slate from Honister Crag, and some difficulty was at first experienced in accepting the true nature of their origin. I was disposed to regard them as having been introduced in meta- morphosed sedimentary fragments, as in the case of the tuff at Falcon Crag, and to suppose that the crystals had remained distinct after the other material of the fragments had been completely obliterated and absorbed into the rest of the slate. But longer observation of this particular occurrence, and of numerous others subsequently found, quite dispelled that idea. There is no doubt that the solutions which have permeated the ash-beds, and which have acted under high pressure (as witnessed by the bubbles in the calcite) and probably high temperature also, have dissolved titanic acid and allowed it to re-crystallize (according to differences of conditions we are not able to specify), either as anatase, more sparingly as rutile deposited in cavities, or in combination with silica and lime as sphene. The anatase occurs mainly as clusters in patches of chlorite. With the perfect crystals are often large numbers of grains not showing definite forms, but apparently deposited at the same time. The mineral occurs also in secondary quartz-grains which are abundant in some of these rocks; in calcite, though rarely, and now and then in felspar-substance. In some cases cavities are seen lined with rutile, and filled in with quartz in which are perfect little crystals of anatase ; so that between the time of deposit of the rutile on the sides of the cavity and the final in-filling with quartz a change of conditions as to nature or temperature of solutions, or both, had taken place, which altered the crystal-forms of the titanic acid being deposited. - It may be noted that in slates which show very much sphene anatase does not usually occur. Otherwise a large number of the 1 Tt is also to be remarked that the small crystals of tourmaline, so usual in clays, shales, and slates, are never seen in these ashes. * Since the above was in print, I have had the opportunity of examining some of these minute anatase crystals by means of a 3’y inch oil-immersion objective. This has enabled me to see them very much better than I ever did before, and to ascertain that 1 was mistaken in stating that the prism-band is present on some of them. The apparent band disappears when the crystals are seen under the great magnification, together with fine definition, which the use of this objective gives us. 222 W. MW. Hutchings—Ash-slates of the Lake-District. slates contain it in varying amount, sometimes very scarce and sometimes in crystals so small as to require very careful search for its detection, but at other times very abundantly and of larger sizes, ranging up to sz/ssth of an inch in length. The various experiments on record as to the artificial formation of crystallized titanic acid by sublimation show that variations of temperature cause variations in the resultant crystal-form ;—rutile, anatase or brookite being obtained at different parts of the apparatus. Similarly the three minerals may be obtained by fusion of titanic acid in different solvents. The same no doubt applies as regards solutions of titanic acid in liquids, and its crystallization out of them under various conditions; but there appear to be very few experi- mental data as to this, and we can only speculate as to the exact nature of the solutions which have acted in these rocks. It is stated by Doelter (Allgemeine Chemische Mineralogie, p. 155) that by means of water containing sodium fluoride he succeeded in re- crystallizing titanic acid in the form of rutile. He also gives interesting figures (loc. cit. p. 189) showing a very noticeable solubility of titanic acid (powdered rutile) even in pure water, in sealed tubes at 80°C. From various considerations it is probable that the solutions acting in these rocks were largely charged with alkaline silicate ; a solution of alkaline titanate was probably formed at the same time, out of which carbonic acid would liberate titanic acid. It seems likely that so far as concerns temperature, pressure, etc., the conditions existing in many of these beds of the Borrowdale Series when the main changes took place, did not materially differ from those under which the Coniston Flags at Shap were meta- morphosed near the granite, exactly similar solution of the titanic acid and re-crystallization as anatase having taken place in some of these flags (Harker and Marr, Quart. Journ. Geol. Soc. vol. xlvii. 1891; also Hutchings, Grou. Mac. 1891, p. 462). Among the various changes which have taken place in the minerals of these rocks, those which concern the felspars have the greatest interest. The points involved are, of course, the same whether we study the felspars in the slates and other detrital rocks or in the altered andesites, and what follows may be taken as applying equally to both classes. The normal decomposition of the felspars of these rocks does not seem, so far as can be made out, to lead to kaolinization.'. The three main types of decay, sometimes singly, sometimes together, give rise respectively to white mica, a very pale chloritic mineral, and calcite. The formation of white mica is very usual all over the district. In many andesites and ashes the felspars, while retaining their original outlines perfectly sharply, are internally quite full of mica flakes, often of good size, hardly ever showing any sort of orientation to the crystal-planes of the containing crystal, but occurring equally in all directions and often as tangled clusters of flakes at all azimuths. This lack of orientation of the mica formed in felspars appears to be not unusual. JI have noticed it in other rocks; and it is pointed out by Rosenbusch (Microscop. Physiog. der Gesteine, p. 28). 1 It is usually considered to be difficult, and indeed often impossible, to distinguish W. MW. Hutchings—Ash-slates of the Lake-District. 223 Among the mica in the larger crystals may often be seen quartz, and usually more or less of perfectly glassy clear felspar. Where the alteration has given rise to the pale chloritic mineral, a more definite orientation appears to largely prevail. This chlorite is very faintly dichroic, and polarizes in thin sections in tints up to yellowish-white of the first order. Calcite frequently accompanies the other two products, and often occurs by itself, in all stages up to the total replacement of felspar erystals by pseudomorphs in calcite. Mr. Alfred Harker, in a petrological appendix to a paper by Prof. Nicholson and Mr. Marr (“The Cross Fell Inlier,”’ Quart. Journ. Geol. Soc. vol. xlvii. pp. 512-525), alludes to the fact that in some of the rocks in question the evidence goes to show that a large part of the felspars are ‘‘ regenerated,” and have a secondary twinning due to crushing. He specially alludes to a rock from Wythwaite Top, giving details as to his observations on the porphyritic felspars contained in it and their alterations (p. 515). Similar occurrences may be noticed more or less all over the Lake District, and these rocks offer a splendid field for the investigation of the many questions, as yet only partially understood, as to the re-generation and re-crystallization of felspars, with or without secondary twinning, due to crushing and shearing. Specimens may be obtained at many points from ashes (fine tuffs and slates), and often from altered lavas, in which the usual turbid felspars full of mica, chlorite, or calcite, with the twinning nearly or wholly obliterated, are replaced by more or less glassy clear crystals often beautifully twinned. These are not crystals and fragments which have escaped decay, but are obviously felspars which are re-formed in situ,—often, apparently, completely re-crystallized and re-twinned. The rocks in which these occur all give full evidence of great stresses, and the felspars themselves are often bent, broken, and re-cemented with chlorite in a most complex manner. In the slates of Honister Crag, and many other quarries, any number of bits may be seen, as clear as fragments of window-glass except for a little brownish dust in some cases, a large proportion of such bits showing beautiful twinning in polarized light. Many other bits, equally clear and glassy, show no twinning whatever, nor any cleavage, and are only to be discriminated from quartz by microscopically between kaoline and muscovite as alteration-products in decomposing felspars. Rosenbusch, for instance, points this out very emphatically (Physiographie der Mineralien, pp. 516, 561). The flaky alteration-product in felspars is certainly sometimes so minute, and occurs in such an indistinct manner, that decision as to its exact character is very uncertain or impracticable. But as soon as the flakes are larger and more distinct (and this is often eminently the case in the rocks now under consideration), I venture to think that the identification of the mica can be sately made. The bi-refraction of kaolinite is high, but so far as my observations go it is very distinctly less than that of muscovite, observing transverse sections in each case. Then again, edge-sections of the mica extinguish parallel, while edge-sections of kaolinite give such very decided angles that no confusion of the two minerals appears possible. J have used for these comparisons the well-known kaolinite crystals trom Anglesey, and also those which occur abundantly (though of smaller size) in the interstices of many coarse sandstones and grits of the Coal-measures. 224. W. M. Hutchings—Ash-slates of the Lake-District. optic tests in convergent light; and in some cases, in tuffs, large decayed felspar-fragments have been re-generated into mosaics of clear grains in the well-known manner, What these felspars now are it does not seem possible to decide on optic tests alone, in thin sections. The multiple twinning in most cases points to plagioclase, and extinctions appear to indicate albite, oligoclase, and andesine as probably the varieties. But nothing short of a laborious isolation and analysis of specimens could give a safe decision. It appears to be usually considered that albite and andesine are the varieties chiefly produced by the dynamic re-generation of decayed original felspars. In the paper above referred to Mr. Harker brings forward the question of the formation of new felspar by deposit in vesicles, and describes a case of such an occurrence in one of the Cross Fell rocks, the felspar in question being well-twinned plagioclase with extinction-angles pointing to albite or andesine. According to my own observations, this mode of occurrence is not by any means very rare, and J can point to several cases of cavities in these rocks which are lined with chlorite, etc., and contain felspar in such a manner as to apparently forbid any other explanation than that the mineral has been crystallized from infiltrations into the cavities. The question first attracted my attention in connexion with the altered rocks round the Shap granite. Messrs. Harker and Marr allude to felspars formed in vesicles by the metamorphism of their contents. They refer to one particular slide in which this is observed, but state that it does not seem to have commonly occurred. Whether it be due to contact-action or not, my own impression is that it is very usual at some points round the granite, as I have several slides in which well-defined felspar, often in good large individuals, frequently occurs in vesicles with quartz, biotite, hornblende, ete. It is mostly plagioclase, but I have one slide, which I have submitted to Mr. Harker, in which occur grains of what seems to be orthoclase, perfectly clear, beautifully cleaved, and extinguishing quite parallel to the cleavages. One such grain is over + inch in diameter filling an irregular cavity, which may have been a vesicle, but seems more likely to have been due to the removal of some former mineral. I at first attributed these large grains, as also the smaller plagioclase in vesicles, to the action of the granite, and this may be correct, but it is not necessarily so, as later observations showed me that all these occurrences are paralleled in rocks far outside the contact-zone. Cavities with plagioclase, and apparently also orthoclase, occur not rarely in the coarser slates at Mosedale, for instance; and the grains of well- cleaved felspar, apparently orthoclase, are seen again in sections of the andesite of Harter Fell, Mardale, where the mineral occurs in a precisely similar manner as large, irregular, perfectly glassy- clear, untwinned grains in a rock whose original felspars are all sharply and definitely bounded, and are now exceedingly turbid. I look upon all these cases as due to causes wholly distinct from the dynamic regeneration of decayed felspars, and as explained by W. WM. Hutchings—Ash-slates of the Lake-District. 225° simple deposit from solutions, exactly as albite, orthoclase, etc., are known to be deposited on a larger scale in veins and cavities. There are also, so far as I can make out, what certainly appear to be orthoclase crystals in some of these rocks, which seem to require another explanation. They are not in cavities, and for various reasons they do not appear to be original crystals, but to be ‘ regenerated ”’ like so many of the plagioclase crystals. I have come, after much consideration of them, to regard them as not improbably pseudo- morphs after former plagioclase, on the theory (or hypothesis) that solutions containing silicate of potash have acted upon these former felspars, removing soda and lime and replacing them with potash, One such crystal observed, which optically fully corresponds to orthoclase, contains a cavity lined with deposited rutile, evidently formed at the time that solutions were strongly acting on the original crystal. In some of the normal andesites the much-altered felspars full of mica, chlorite or calcite, show in among these secondary products, as before stated, more or less of clear glassy material. It is not an uncommon thing to see this glassy felspar in considerable quantity in long streaks and patches, and where the outline of the crystal is fully preserved, as often is the case, to see that this felspar is optically uniform all over the crystal, is quite free from twinning and extinguishes perfectly parallel to the crystal-boundaries, or at angles which point to orthoclase. In some of the rocks crystals are frequent which are wholly glassy clear, save for trifling inclusions, and behave as above described, occurring together with plagioclase which is obviously regenerated. Such changes as I suggest may have taken place do not appear at all unlikely under the conditions which we have reason to infer obtained during the alterations these rocks have undergone, and there appears to be good independent evidence that they have been observed and chemically proved elsewhere. A leading authority in this class of investigation appears to be Lemberg. I have not at present an opportunity of consulting his original papers, but in Roth (Chemische Geologie, vol. i.) among other abstracts from and references to Lemberg’s work are certain facts which bear very directly on the point in questions. Thus, Lemberg analyzed oligoclase from the tourmaline-granite of Monte Mulatta, and its green alteration-products in four examples, a, b, c,d. The alkalies were as follows :— Original Oligoclase. a. b. ¢. a. Soda = 7-26 per cent. 2°14 p.c. O-70p.c. 2°23 p.c. 0:84 p.c. Potash = 2°10 ,, SOEs ROMS pn) CY oy) gee water is also taken up at the same time. Other analyses of Lemberg’s are also given, showing similar changes in oligoclase, some chloritic mineral being apparently formed, with a simultaneous removal of soda and increase of potash. An analysis of labradorite is also given, together with that of its altera- tion-product, showing— DECADE IlI.—VOL. IX.—NO. V. 16 226 =W. M. Hutchings—Ash-slates of the Lake-District. Original labradorite. Alteration-product. Soda ... 6°43 per cent. 0-88 per cent. Potash... 0°92 ,, Si Lain, and in another still more extreme case the alteration-product con- tained Soda = 0:17 p.c.; Potash = 9°71 p.c. From this latter alteration-product acid extracted 387-61 p.e. of a silicate of magnesia, alumina and iron oxides,—evidently a chloritic substance. The residue left atter this extraction contained very nearly all the potash, ‘and corresponded in composition to orthoclase.” These alterations appear to be exactly cases of what I suppose to have taken place in some of the andesites. A chloritic mineral is formed, with a simultaneous more or less extensive chemical alteration of the soda-lime felspar, tending to convert it into orthoclase. In these Lake District rocks powerful dynamic action, following on the chemical change, may be supposed to have completed the work in re-erystallizing the felspar-substance. Jt will not affect the question, whether chlorite, mica or calcite is formed during the chemical stages of these processes. In commenting on the above results of Lemberg, Roth points out that it is not indicated from what source the potash was supplied which was taken up during the changes of the felspars. In the case of the rocks we are considering there is no difficulty as to such source. I have shown how frequently white mica is formed in the alteration of some of the felspars of these rocks, and how specially and very largely this is the case in the beds of fine ash and tuff. In these ash-beds the finely-pulverized material has undergone these alterations as a whole, including the portion which in the massive andesites is consolidated as ground-mass, considerably richer in potash than the 1est of the rock, but undergoing these changes, as a rule, in a very much less degree. These changes, as we have seen, entail a considerable liberation of potash as soluble silicate, and we may be sure that during their progress all these rocks, as a whole, were permeated by solutions containing that salt, and also carbonate of potash. These solutions would play an important part in further changes, and acting upon soda-lime felspars (themselves containing more or less of potash) already in course of decay, would easily and naturally bring about the alterations supposed. No doubt similar explanations would apply in the cases proved by Lemberg. Lemberg was apparently able to isolate the special felspars, the alterations of which he wished to study. Such isolation is, un- fortunately, not possible in the case of the rocks to which I refer. The felspars are so small that the picking-out of them is not practicable, and their isolation from the crushed rock by means of dense solutions is a tedious and difficult matter. Also it is not possible in this manner to separate the different varieties of felspar one from the other, as even in the most favourable of the occurrences examined, the included secondary minerals, though small in amount, suffice to completely counteract the normal differences of specific gravity. W. MW. Hutchings—Ash-slates of the Lake-District. 227 Under these circumstances it has not been possible to obtain any very effective chemical evidence on the point in question. The most favourable rock in my possession is an andesite from a point not far from Ulleswater, on the road to Matterdale. Its ground-mass is fine-grained, and appears to have been originally “hyalo-pilitic.” There are numerous well-defined pseudomorphs of chlorite after augite. The porphyritic felspars are numerous, but small, ranging from about 35th of an inch in length as maximum. They are largely more or less glassy clear, and contain comparatively little of secondary minerals ;—chlorite, calcite, a little epidote, with but little mica in this case. A good many of them show the appearances above stated which lead me to suppose they are perhaps orthoclase. The rest are plagioclase, of which, as usual, it is not possible to safely determine the variety, though oligoclase appears to be present. A large piece of this rock was pulverized and reduced to uniform very small grains by means of wire gauzes of suitable mesh. The powder was subjected to repeated separations in liquids of diminishing specific gravities, the lighter portions being successively concentrated, a final separation being made in a liquid in which a fragment of pure labradorite just remained suspended. In this manner, with plenty of time and patience, it was possible, in spite of the unfavourable nature of the rock and of the smaliness of the grains, to separate from a large bulk a small quantity of material which proved to be felspar, free from ground-mass, and contaminated only by small amounts of chlorite and calcite. This was finely powdered, digested a short time in hydrochloric acid of moderate strength (sufficient to decompose chlorite), and finally in dilute potash liquor to remove separated silica. The residue, well washed and dried, was practically pure felspar. A sample of the bulk of the powdered rock contained: Silica, 62-43 per cent.; Soda, 4:13 per cent.; Potash, 2:28 per cent., as kindly determined for me by Dr. J. B. Cohen. This does not differ appreciably from the average run of analyses of local andesites, though the potash is perhaps a trifle higher than usual. The isolated felspar-substance was analyzed by Mr. Paterson and contains Soda 8°52 p.c.; Potash 4:1 p.c. Having regard to the facts that in all rocks of this class the potash concentrates in the ground-mass, and that the average of the entire rock is here only 2:28 p.c., we should not expect to find anything like so much as 4 p.c. potash in the porphyritic felspars. Its presence in them in this amount would seem to justify the in- ference that some of them are specially rich in it, and that, indeed, ‘some potash-felspar is probably present together with the plagioclase. In some of these rocks, again, there appear to be examples of those very interesting phenomena which have been so beautifully described and illustrated by Prof. Judd in his paper, “On the Growth of Crystals in Igneous Rocks after their Consolidation” (Q.J.G.S. vol. xlv. 1889). They are not so large nor so striking as the instances quoted and 228 Notices of Memoirs —Oolites of Northamptonshire. figured in that paper, but there are in some specimens crystals which show all the principal appearances enumerated by Professor Judd, aud which cannot, I think, be explained satisfactorily in any other manner than that which he has given us. IN @ PECs Ole AVManwVE@ierS- pass HS, I.—Tse Ooxuitic Rocks at Srowsk-NINE-CHuRCHES, NORTHAMPTON- suire. By Brresy Tuompson, F.G.S., ete. (Journ. North- amptonshire Nat. Hist. Soc. Vol. VI.) N this paper Mr. Thompson describes a section of especial interest, as it shows the sequence of beds from the Northampton Sands to the Oxford Clay. The tract near Stowe, situated about seven miles west of Northampton, is a faulted one, and to this cause is due the preservation of the Great Oolite and higher beds, which elsewhere in the immediate neighbourhood have been removed by denudation. The beds have been quarried chiefly to supply limestone for fluxing purposes to the Heyford furnaces near by. The chief new points in this paper concern the identification of the small area of beds overlying the Great Oolite, as these were not indicated on the Geological Survey Map. The highest bed beneath the Drift soil is a blue clay grouped as Oxford Clay. There can be little doubt that this represents the clay usually found between the Cornbrash and Kellaways rock, and sometimes designated the Kellaways Clay. The Cornbrash contains some of the usual fossils met with in the formation, and it rests on a series of beds grouped with the Forest Marble and Great Oolite Clay. The presence of beds of flaggy limestone resembling varieties of Forest Marble is of interest, as they are only occasionally met with in the country to the north- east of Bicester, in Oxfordshire. The Great Oolite Clay is not, as Mr. Thompson thinks, the bed to which the term ‘Cornbrash Clay’ has been applied; that Clay, where it occurs, overlies Cornbrash rock, partly replaces it, and passes up into the Kellaways Clay. The Great Oolite Limestone and lower beds are described by Mr. Thompson, and lists of fossils are given from these as well as from the higher strata. A photographic plate and a plate of diagram- sections illustrate the paper. He Bi OWe II.—Notes on tHE Fosstr APHIDH AND TETTIGIDA. IN Mr. G. B. Buckton’s late Monographs on British Aphides » and Cicada, are thoughtful remarks on the known fossil forms of these two great families of Insects, and we here reproduce them as interesting to our readers,—premising that these Insects belong to the Homoptera, whose zoological relationship is as follows— Hemiptera: A. Homoprera: Aphides, Coccide, Cicada, Fulgo- rid@, ete. Notices of Memoirs.—G. B. Buckton on Fossil Aphide, etc. 229 B. Hereroprera: Hydrocoring (Water-bugs), Geocorisa (Land- bugs). iL In the “Monograph of the British Aphides,” vol. iv. 1883, Ray Society, at pages 144—178, Mr. Buckton gives a sketch of the geological occurrences of Insects in general, and of the Aphidine in particular, and finds that the Hemiptera are nearly as ancient as the Coleoptera, and apparently preceded the Diptera, Hymenoptera, and. Lepidoptera. The earliest known Aphides have been recognized by Westwood, as collected by Brodie in the Purbeck beds of Wilts and Dorset. In the Eocene Tertiaries of Europe Aphis occurs fossil ; and even if not present, its enemies who fed on it (Syrphide and Coccinellideg) and others (Ants) that sought its honey-dew, have left their remains. At Radaboj in Croatia, and Giningen in the valley of the Rhine, Aphides are present in Miocene strata. Indeed in the Swiss Miocene 106 species are known. The Aphidide of North America have been described by Scudder from the White-River District in Utah, and the Green-River-Station in Wyoming; also from the Florissant-Lake strata in Colorado, the last giving eight species of Aphidine. The many species of Aphides found in Amber have occupied the author’s attention (pages 160-168). He gives a lucid account of what has been published about Amber and its origin; and indeed he also alludes to what geologists have deter- mined about the Tertiary and other strata in which Aphides occur, and especially about the flora represented by the plant-remains accompanying these Insects at the several localities. Plate cxxxi. contains figures (after Berendt) of Germar and Berendt’s species from Amber; namely, three of Aphis (?) and two of Lachnus (?), carefully described in the text. In plate cxxxii. Mr. Buckton figures, from earlier drawings, one Aphis (2?) from the Purbeck; one from the Tertiary of Amberieux (Ain) ; one Aphioides from Amber; four of Aphis (?) and three of Lachnus (?) from Radaboj ; and a Pemphigus (?) from Ciningen. Some fossil Aphides from Florissant, Colorado, are figured (after Scudder) in plate cxxxiii. Five new genera are described by Buckton, at pages 176-178, as Siphonophoroides (2 spp.), Archi- lachnus, Anconatus, Schizoneuroides, and Pterostigma (1 sp. each). Ill. In Mr. G. B. Buckton’s “ Monograph of the British Cicade or Tettigide,” 1891, Macmillan & Co., London and New York, some; fossil forms are referred to in vol. i. at pages 164-184. After some remarks on the bibliography of Fossil Insects, their occurrence in freshwater rather than in marine deposits, their local abundance in isolated groups or masses, and the possible conditions of preservation, the author observes that the Hemiptera lived in Carboniferous times in the American and British areas, contem- poraneously with the gigantic Dycteoptera (Cockroaches) and Coleoptera (Buprestide) which crawled amongst the Hquisetums and Tree-ferns of that early period. A few Hemipterous remains are described by Scudder from beds below the Lias or Rhatic in Colorado; and some specimens from the Rhetic at Schonen in Sweden have been referred to Cimex and Cicada. From the Kheetic (?) 230 Notices of Memoirs—G. B. Buckton on Fossil Aphide, ete. of Schambelen (Aargau), Switzerland, O. Heer enumerates 143 fossil Insects, of which 12 are Hemiptera. The Jurassic Paleontina oolitica, from Stonesfield, was referred by Mr. A. G. Butler to Lepidoptera, but others believe it to belong to Cicade. In some of the Purbeck beds of Wilts and Dorset Insects are known to be abundant, as shown especially by Brodie and Westwood, in 1844 and 1854. Of the Tettigide, Prof. Westwood determined remains of a small Cicadellina, and of a Cercopis and Bythoscopus. Though Insect remains are plentiful in many Eocene Tertiary beds, only in the gypsum of Aix-en-Provence have discoveries of Cercopide, Civiide, and Cicadelline been made. To the Oligocene period Mr. Scudder refers the remarkable fresh- water insectiferous deposits of Colorado, which form part of islets in the Florissant Lake. The fauna and flora agree partly with those of Ciningen near Schaffhausen, and Radaboj in Croatia, which belong to the Miocene. In British Columbia, Dr. G. M. Dawson discovered some lacustrine insect-bearing strata, believed also to be Oligocene in age ; and they have yielded to Mr. Scudder 19 Hemiptera, of which only two are truly Hemipterous ; whilst there are eleven Homopterous Cercopide, three Fulgoride, and two Aphide. All are of larger size than the usual Tertiary Insects. Of all the American fossil insects, from areas far apart, 612 species have been described, of which the Hemiptera form the large proportion of 266 species, and Mr. Scudder regards the known European species of Hemiptera as numbering 218. The Miocene of Switzerland has yielded multitudes of fossil Insects, mostly discovered and described by O. Heer. Among them are 636 Hewmipterous species; and by far the majority of these are larval forms. The presence of at least one Cicada, and the numerical preponderance of Reduviide, Scutata, and Coreodee, also the occurrence of several fine Cercopide and large Water-bugs, give good evidence that a warmer climate (especially milder winters) then prevailed over Central Europe than now. O. Heer thought also that as these insects undergo an incomplete metamorphosis, and are more or less active in their pupal conditions, they were better suited to regions not subjected to the rigours of long cold winters. From the Miocene of Greenland and Spitzbergen examples of Cercopis and Pentatoma have been obtained. From New South Wales Mr. R. Etheridge, jun., has described (1890) the fossil Cicada Lowe. The Amber of the Baltic and elsewhere (pp. 171-173 ; see also “Monogr. Aphides,” pp. 160-165) contains many specimens of Tettigide, of these Mr. Buckton’s Plate G illustrates two specimens of Typhlocyba, two (?) of Jassus, one of Tettigonia, and four of Ciaius; also one Cicada in copal-resin from Zanzibar. Of other fossil Tettigide, Mr. Buckton’s Plate F illustrates Butler’s Palaoutina oolitica (elytron); two species of Cicadellium and one of Cercopidium, from the Purbecks; one Cicada and two species of Cercopodium from the Swiss Miocene; one Agallia, one Petro- lystra, and one Palecphora, from the Oligocene of Colorado; also Reriews—Sir R. Ball’s Ice-age. 231 a Thammotettiz, a Dawsonites, and a Stenecphora from the Tertiary of British Columbia. At pages 178-181 Mr. Buckton refers to geological speculations as to the changes of land and climate affecting Insect-life in late Tertiary and Quaternary times; also to possibilities of development and of degeneration among Insect forms in geologic times, and he hesitates to offer any outline of the phylogenetic descent of the Homoptera in particular. UMS leks dlc REVIEWS. I.—Tue Cause or an Ice Acs. By Sir Rosert Bauz, LL.D., F.R.S., Royal Astronomer of Ireland. Pp. 180. (Kegan Paul, Trench, Triibner & Co. 1891.) HIS little book contains a very clear and agreeably written ex- position of the commonly received Astronomical theory of Glacial periods. But it goes further than that, because it offers an explana- tion of a difference of the mean temperatures of either hemisphere during the summer and winter seasons, reckoning from equinox to equinox, which has not hitherto been taken due account of in estimating the effects of the earth’s position with reference to the sun. The author proves, by a short calculation given in an Appendix, that owing to the obliquity of the ecliptic the quantity of heat, received from the sun upon one hemisphere during its summer, bears to the quantity received during its winter the invariable pro- portion of 63 to 87. This will be the case always, whatever be the position of the equinoctial line with respect to the major axis of the orbit, and whatever be the eccentricity of the orbit. He points out that, in consequence of an inadvertence in a statement in Herschel’s Outlines of Astronomy, the proportion has hitherto been regarded as one of equality ; and it is obvious how great a difference this consideration will make in estimating climatic effects. The greatest eccentricity which the earth’s orbit can have is about 0-07. When with this eccentricity winter in the northern hemi- sphere occurs in aphelion, taking the mean daily heat for the whole year received by that hemisphere, as unity, the mean daily heat received by it in a short summer of 166 days will be represented by 1:58; and the mean daily heat received in its long winter of 199 days will be only 0°68. ‘This, the author says, will produce a severe glacial epoch, when the summers will be short and very hot, and the winters long and very cold. While the eccentricity remains the same (for it changes very slowly) when the axis of the earth is next carried round by precession until the winter occurs in perihelion, the mean daily heat received in a long summer of 199 days will be 1:16, and in a short winter of 166 days will be 0-81. This he believes will produce an interglacial period—interglacial because two or three such reverses may occur before the eccentricity is sensibly altered. It must be remembered that the unit of heat here used is a very large one, being that which raises the mean temperature of 232 Reviews—Sir R. Baill’s Ice-age. the hemisphere from that of space to that which it actually has, which rise may be perhaps measured by 300° F.; so that 0-1 may represent a difference of 380° F. The above may suffice to point out the importance of the work in regard to the astronomical theory of the Glacial epoch. It adds fresh force to Dr. Croll’s hypothesis. There appears to be a slip at p. 95, where it is said that, “ with the present eccentricity of the Harth’s orbit, the greatest possible difference between summer and winter would amount to 33 days, ete.” Such a difference could only occur when the eccentricity had its highest value of 0:07, whereas at present its value is only about 0-017. Sir Robert Ball does not venture to say when the last ice age took place, nor when the next may be expected; but only that, when they do occur, they will be separated by 21,000 years. with inter- glacial periods intervening. Prof. Darwin, in his notice of this book in “ Nature,” Jan. 28, regrets this reticence, and inquires whether Leverrier’s formule, which Croll used, may not be relied on to give an approximation to the value of the eccentricity for about 100,000 years in the past. Croll constructed an elaborate chart, showing the eccentricity for three millions of years in the past, and one million in the future. Considering the enormous labour with slight mathe- matical powers at his disposal, it makes one sad to think that much of this labour was not more profitable; but if the formule can be depended on for 200,000 years in the past, an eccentricity of 0°0569 occurred at about that date, which, on his hypothesis, might have been sufficient to bring about the Glacial epoch.! Looked at from the geologist’s point of view, this book seems rather too triumphant. The author appears to think there are fewer difficulties remaining than the geologist would admit. For instance, he attributes the climate of what are now Arctic regions, at the time when a luxuriant flora flourished there, to an interglacial period. But, seeing that a single night of severe frost will kill a fig-tree, it is hardly credible that, even with a short winter and a nearer sun, frosts should never have occurred at a place within the Arctic circle, which would have been fatal to such vegetation.» Again, he points out that the astronomical theory necessitates the recurrence of glacial epochs through all past geological time, and to explain away the objection that glacial deposits and scratched stones are not to be met with to testify to their frequent recurrence, he refers to the unconsolidated and perishable nature of such deposits. But Till and Boulder-clay are less destructible than many clays, and other unconsolidated deposits, which have been buried again and again under newer strata without being disturbed; and they occur in India possibly in Paleozoic strata.’ Other points will occur to the geologist where difficulties appear to be passed over. But although a few passages betray that. ‘‘ The 1 See a paper on the Ages of the Trail and Warp by the writer, Grou. Mac. Vol. IV. pp. 193-199, 1867. ® See discussion on Prof. 0. Heer’s paper on fossil plants from North Grinnell Land; Quart. Journ. Geol. Soc. 1878, vol. 34, p. 70. 3 Quart. Journ. Geol. Soc. 1878, vol. 34, p. 375. Reviews— Paleozoic Fishes. 233 Cause of an Ice Age” is not the production of a professed brother of the hammer, nevertherless it will well repay perusal, and all must acknowledge that a valuable contribution has been made by a distinguished ally, bearing upon one of the most difficult problems of our science. O. Fisumr. IJ].—Pautmozoic FisHes. 1. On THE CHaractErs oF some Patmozoic Fisues. By EH. D. Corr. Proc. United States National Museum, Vol. XIV. (1891), pp. 447-463, Pls. XX VIII.-XXXIII. 2. Unser Prericuaruys. By J. Victor Ronon. Verhandl. Russ. Kais. Mineral. Ges. St. Petersburg, Vol. XXVIII. (1891), pp. [1-25 reprint], Pl. VII. UR knowledge of the Paleozoic Fishes is still progressing rapidly both in Europe and America, and we have lately received the two papers on this subject quoted above. Prof. Cope’s communication is divided into seven parts, and deals with several important types; Dr. Rohon’s work is chiefly an examination of the histological structure of the shield of Péerichthys. The first fossils noticed by Prof. Cope are referable to Elasmo- branchii. A detatched tooth from the supposed Permian of eastern Nebraska, named Styptobasis Knightiana, is very remarkable on account of the small size of its base of insertion; we should, indeed, prefer to have some information as to its microscopical structure before accepting the fossil definitely as an Hlasmobranch tooth. A typical spine of Ctenacanthus (C. amblyxiphias, sp. nov.) from the Permian of. Texas is a noteworthy discovery; and the first truly hybodont fin-spine met with in the New World (Hybodus regularis, sp. nov.) is also of much interest, though it is not Palaeozoic, being from the supposed Trias of Baylor County, Texas. The Elasmobranch fragments are only of limited importance, but Prof. Cope’s description of the cranium of Macropetalichthys—one of the most remarkable and least understood American Arthrodira or “« Placoderms ”—tends towards a considerable advance in our know- ledge of the great extinct group of fishes to which it belongs. As pointed out by Prof. Cope, this genus is not related in any way to the Sturgeons, notwithstanding the contrary assertions of several observers; and the plates of the head-shield are shown to be arranged much as in Coccosteus, Dinichthys, and the otber Arthrodira. The hinder part of this shield, it is stated, “does not seem to have protected the brain, but rather the anterior part of the vertebral axis, and seems to have been a nuchal plate.’’ Exactly the same Opinion has already been expressed in reference to the so-called “occipital region ” of the Scottish Homosteus (Proc. Zool. Soe. 1891, pp. 198-201). The base of the cranium in an Arthrodiran is now described for the first time, Professor Cope’s specimens of Macro- petalichthys displaying a good deal of this region; and the detailed anatomical description is followed by a discussion of the relationships of this type of fish in the light of the new facts adduced. On the 234 ' Reviews—Patleozoic Fishes. whole, Prof. Cope is inclined to accept the conclusion arrived at in the British Museum Catalogue of Fossil Fishes; namely, that the Arthrodira are extremely specialized Dipnoi. ‘The nuchal portion [of the head-shield of Macropetalichthys| with its lateral nuchal elements is represented by the cartilaginous mass which extends posterior to the median occipital bone in Ceratodus, in which this region has very much the form of the nuchal shield in Maero- petalichthys, although it is relatively shorter. The chordal groove with its descending laminz resembles much the produced occipital bone of Lepidosiren. The parasphenoid in both Lepidosiren and Ceratodus is produced posteriorly abnormally, and it is only necessary to imagine this part to be reduced to its normal length to have the conditions found in Mucropetalichthys. The broad parasphenoid and vomer remind one of that of Ctenodus. As I have shown that Macropetalichthys is allied to Dinichthys, we can add in favour of the supposition of affinity to the Dipnoi the peculiar dentition of that genus. The ectetramerous structure of the dorsal fin shown by Von Koenen and Traquair to exist in Coccosteus, and shown to be probably present in Dinichthys by Newberry, are in favour of the Dipnoan theory.” Prof. Cope evidently continues in the belief that Pterichthys and its allies have no connexion whatever with the Arthrodira; and the researches of Dr. Rohon quoted above come as a welcome con- firmation of this view. Dr. Rohon points out that the histological structure of the shield of Pterichthys is very different from that of Coccosteus, and closely similar to that of Pteraspis, Tremataspis, and their allies. This result also confirms the arrangement of the early fishes in question in the second part of the British Museum Catalogue. Prof. Cope’s remarks on the limbs of Holonema and Megalichthys, however, are far from satisfactory. In the first place, we venture to re-affirm that the so-called dorsal shield of Holonema is really the ventral shield turned the wrong way forwards; and the genus belongs to the Arthrodira, not to the Ostracodermi. The limb referred by Prof. Cope to /olonema is the distal segment of the arm of Bothriolepis, originally named Stenacanthus by Leidy. It is stated that “the spine differs from that of both Bothriolepis and Pterichthys in being without complete segmentation;” on the other hand, we may remark, the distal half of the arm of Bothriolepis is nearly always incompletely segmented. With regard to the paired fins of Megalichthys, which are said to ‘approach those of the Arthrodira very distinctly,” we venture to assert, from a knowledge of other Osteolepide, that the apparent simplicity of the arrangement of the cartilages in Prof. Cope’s specimens is due to imperfect preservation, while the paired limbs of the Arthrodira are far too imperfectly known to admit of comparison. The final result of Prof. Cope’s researches in the Crossopterygian ganoids is of great interest, and briefly summarized in an amended classification, which we propose to consider elsewhere on a future occasion. The Professor is at last converted to the belief that the Paleeoniscide and Platysomidee are closely related to the primitive Reviews—Hutchinson’s Story of the Hills. 235 Sturgeons; and he concludes his memoir by the description of two new species of Platysomus, one from the Permian of the Southern Indian Territory, the other from the Coal-Measures of Mazon Creek, Illinois. Jars fh \Wlc IlJ.—Tue Srory or tHe Hirtis: A Porunar Account or Mountarns AnD How THEY were Maps. By Rev. H. N. Hurcurnson, B.A., F.G.S. (London, Seeley & Co., 1892.) OPULAR works on geology are rapidly multiplying, and it becomes more and more difficult to devise any new method of treatment of the subject. Mr. Hutchinson’s little book, however, is a pleasing novel version of the old story, interwoven with much interesting information outside the geologist’s sphere and illustrated by very beautiful photographs of scenery. There are also numerous extracts from Ruskin’s ‘Modern Painters,” from Geikie’s ‘‘ Scenery of Scotland,” and from other well-known prose-writers and poets that help to enliven the volume. Mr. Hutchinson’s style is terse and clear, without technicalities, and thus precisely adapted to the general reader for whom the “Story ” is intended. The first section of the book deals with mountains as they are. The functions of mountains as barriers between races of men, as retreats for conquered tribes, and as influencing climate, are treated in succession. Mountain plants and animals are then discussed, with special reference to the Alps of Central Europe. The second and larger section of the book is concerned with the manner in which mountains were made, and is purely geological. Mr. Hutchinson compares the making of a mountain with the building of a cathedral, describing in succession the three processes », of “ transportation, elevation, and ornamentation” of the materials. Volcanic mountains also have a special chapter; and the volume concludes with some general considerations on the age of mountains. On all points the information is varied and well up to date, and Mr. Hutchinson’s little book may be recommended alike to the school-boy naturalist and to the ordinary mountain-climber who desires to know something of the nature of the peaks and passes among which he spends his holiday. IV.—Catatocus or tHe Type Fosstts In THE WooDWARDIAN Museum, Campripce. By Henry Woops, B.A., F.G.S. (Cam- bridge, University Press, 1891.) HE Woodwardian Museum contains so large a series of fossils to which reference has been made in published works, that a Catalogue like the present will prove of much value to all who are actively engaged in palzontological research. More especially is this the case, since the Woodwardian Professor has full power to exercise his discretion in lending the specimens under his charge to competent investigators far from the University of Cambridge. It is now possible to determine at a glance whether or not any particular type or described specimen occurs in the Woodwardian 236 Reviews—Catalogue of Type Fossils. collection, and much labour and time will thus be saved in making enquiries. The Catalogue is prefaced by some general remarks by Professor Hughes, who directs attention to the historical interest of some of the older collections in the Museum. The original cabinet of Dr. John Woodward includes that of the Sicilian naturalist, Agostino Scilla, born in 1639; and another collection of the seventeenth century is that of Lister, who opposed the views of Scilla in an article entitled ‘*De Conchitis sive Lapidibus qui quandam simili- tudinem cum conchis marinis habeant.” These are not catalogued in the volume before us, which deals only with the collections of the present century. Of the principal modern collections an alphabetical list is given in the Introduction. Numerous Upper Carboniferous fossils were obtained from the late Mr. John Aitken. A series of specimens from the Paleozoic formations of Bohemia was purchased from M. Barrande in 1856. The collection of Mr. J. H. Burrows, purchased in 1872, comprises Mollusca and Brachiopoda from the Carboniferous Limestone of Settle. The De Stefani collection of Italian Pliocene fossils was purchased in 1882; and a fine series of British Pliocene fossils, with others from the Cretaceous and Upper Jurassic, formed by Mr. Montagu Smith, was presented in 1883. Mr. Kinsey Dover presented his cabinet of Trilobites and Graptolites from the Skiddaw Slates in 1890; and the Rev. O. Fisher has long been a generous donor to the Museum in many departments. Other donations are the Forbes-Young collection of Chalk fossils, the Goodman collec- tion of Tertiary fossils, and the Walton collection of British Jurassic fossils. The series of Corals, Trilobites, etc., from the Wenlock Limestone, collected by Captain T. W. Fletcher; the Cretaceous collection of the Rev. T. Magee; and the large collection of Mr. John Leckenby, from the Jurassic and Cretaceous of York- shire, are other important purchases. Many fossils, chiefly Mollusca and Brachiopoda, from the Inferior Oolite of Somerset and Dorset, were purchased from Mr. H. Monk in 1885; and the large and varied collection of the late Mr. H. HE. Strickland was bequeathed in 1888. By the purchase of part of Count Miinster’s collection in 1840, the Museum acquired a large series of Triassic and Jurassic fossils from the Continent; while the donation of part of Mr. J. Hawkins’ collection of Saurians from the Lias in 1856, and the purchase of Dr. H. Porter’s collection of Saurians from the Oxford Clay of Peterborough in 1866, made important additions to the series of fossil Vertebrata in the Museum. Local fossils have been obtained by innumerable donations and purchases. The genera and species in the Catalogue are arranged in alpha- betical order under their respective classes, and cross-references are given to the synonyms introduced. The list everywhere bears evidence of most careful preparation, and the typography is well arranged for convenience of reference. When so much labour and care have been bestowed, it may appear ungracious to criticize ; but we must express the opinion that if Mr. Woods had clearly dis- Reports and Proceedings— Geological Society of London. 237 tinguished between “types” and those specimens merely noticed or figured, his work would have been of much greater use. More- over, personal expressions of opinion, which may be right or may be wrong, seem quite out of place in a list of this kind, which ought to be nothing more than an index to the origin of certain names that have been used in Systematic Paleontology. ARIS Oust YNAN TAD) AS1SOOC Ja AO EAN KES —————_— GEOLOGICAL Soctrty oF Lonpon. T.—March 23rd, 1892.—W. H. Hudleston, Esq., M.A., F.RS., President, in the Chair.—The following communications were read : 1. “On the Occurrence of the so-called Viverra Hastingsie of Hordwell in the French Phosphorites.’” By R. Lydekker, Esq., B.A., F.G.S. The author shows that Viverra Hastingsig, Davies, is common to the Oligocene of France and Hordwell, and finding that there is no character by which the lower jaw of the type of the latter can be satisfactorily distinguished from the type of V. angustidens, Filhol, he considers that V. Hastingsi@ is specifically inseparable from V. angustidens, and figures the cranium which is the subject of the ecmmunication under the latter and earlier name. He gives a list of seven mammals known to be common to the Headon beds of Hordwell and the Isle of Wight, and the French Phosphorites. 2. “Note on two Dinosaurian Foot-bones from the Wealden.” By R. Lydekker, Hsq., B.A., F.G.S. In this paper the third right metapodial (metacarpal?) and an associated phalangeal of a Sauropodous Dinosaur, obtained by Mr. C. Dawson from the bone-bed of the Wadhurst Clay, are described, and referred with doubt to Morosaurus. The author also discusses the relationship of Acanthopholis platypus from the Cambridge Greensand. 3. On the Microscopic Structure, and residues insoluble in Hydrochloric Acid, in the Devonian Limestone of South Devon.” By Edw. Wethered, Esq., F.G.S., F.C.S., F.R.M.S. Microscopic examination of the Devonian Limestones of South Devon shows that they have been built up by calcareous organisms, but that the outlines of the structure have for the most part become obliterated by molecular changes, and the limestones are often rendered crystalline. In connexion with this the author alludes to the disturbances which have affected the limestones. He finds occasional rhombohedra of dolomite, and discusses the probability of their derivation from magnesian silicates contained in the rocks. A description of the insoluble residues follows. The micas, the author considers, may be of detrital origin, but this is by no means certain; he is disposed to consider that the zircons, tourmaline, and ordinary rutile were liberated by the decomposition of crystals in 238 Reports and Proceedings—Geological Society of London. which they were originally included. Minute crystals, referred to as ‘microlithic needles,’ resemble ‘clay-slate needles,’ but are not always straight : they occur in every fine residue, and as inclusions in siliceous and micaceous flakes. The siliceous fragments which enclose them frequently contain many liquid inclusions, which does not necessarily imply any connexion between the two, though there may possibly be some connexion. Micro-crystals of quartz occur, and have been derived from decomposing silicates. IJ.—April 6, 1892.—W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.—The following communications were read : 1. “Geology of the Gold-bearing Rocks of the Southern Trans- vaal.” By Walcot Gibson, Esq., F.G.S. The author describes the general characteristics of the rocks of the Southern Transvaal, and gives a summary of previous work on the area; he then discusses the physical relations of the gold- bearing conglomerates and associated rocks in the Witwatersrandt district, and describes the various rocks in detail. He concludes that the gold-bearing conglomerates and the quartzites and shales of the Witwatersrandt district (which have undergone considerable metamorphism) form one series, of which the base and summit are not seen; that this series is much newer than the gneisses and granites on the eroded edges of which they rest, and older than the coal- bearing beds which unconformably overlie them; that the entire series associated with the gold-bearing beds has been thrust over the gneisses, and was not originally deposited in its present position, the movements having taken place in two directions, viz. from south to north and from east to west; that, after the cessation of these movements, the strata were injected with basic and sub-basic igneous material, and much of the country was flooded with lavas of the same character; and that the con- glomerates have been formed mainly at the expense of the under- lying granites, and gneisses which were largely threaded with auriferous quartz-veins and contained larger masses of quartz. The author then describes the geology of districts outside the typical area, which, though at first sight more complex, are really simpler than that of the typical area. ‘I'he conclusions arrived at from an examination of these areas confirm the results of the study of the rocks of the Witwatersrandt district. 2. “The Precipitation and Deposition of Sea-borne Sediment.” By R. G. Mackley Browne, Esq., F.G.S. The author discusses the,mode of deposition of current-borne sediment upon the ocean-floors, and considers the effects of current- action in sifting the material and causing it to accumulate into stratified linear ridges having directions generally parallel with those of the currents—the dip of the strata varying according to the velocity of the currents. He considers that the conclusions deducible from his analysis appear to be in accord with the evidence afforded by the structure of ancient subaqueous sedimentary deposits. Correspondence—Dr. A. Irving. 939 3p g CORRESPONDENCE. ARCHAAN LIMESTONES ON THE FLANK OF THE MALVERN RANGE. Sir,—The works which have been in progress for some weeks for the new reservoir of the Great Malvern Waterworks on the north- east flank of the Hereford Beacon have already brought to light a fact of no inconsiderable importance in its bearing upon the geology of this most interesting region. Briefly it may be described as follows:—The reservoir is to be formed by a huge dam to be con- structed across the deep valley which runs down from the north- eastern flank of the Beacon, between the two most northerly of the four spurs or buttresses which most geological writers on the district have noticed abutting upon the Triassic plain of the Severn. It is in the deep wide trench which has been excavated for the foundations of this dam that the limestone is best exposed. The rock is a compact crystalline limestone, with a more or less distinct bedding, though much jointed in all directions, as if by incipient crushing, probably somewhat dolomitic, of a light-grey colour on fresh fractures, but in the more decomposed portions stained with oxides of the heavier metals; secondary crystals of calcite are often formed in quantity on the divisional planes of the rock. Of the age of the rock (which so far appears to be absolutely unfossiliferous) there cannot be very much doubt. As the field- relations show that it cannot be younger than the complex of lavas and altered tuffs and volcanic muds of the hills between which the valley lies, a complex of rocks which two of the most capable judges on this question (Drs. Callaway and Hicks) refer to the Pebidian (later Archean). My first visit to the spot was in company with Dr. Callaway, about a week ago; and the suggestion that the rock is one “archean limestone of chemical origin” was made by him. On a second visit yesterday with my friend Mr. H. D. Acland, of Malvern, I was able to follow the exposition which the foreman of the works gave of its position in relation to what he called the “whin-rock.” It strikes nearly north-west, and dips at an angle of about 80°. It alternates with the “ whin-rock,” which seems related to it as an ‘“‘interbedded trap ” (as if the two rocks were contempor- aneous portions of the Pebidian series of this locality), or possibly, from the fact stated to us that the limestone is “ softer and easier to work against the ‘“‘whin” (as if the latter were intrusive), even somewhat older than the volcanic series. Macroscopic examination of some specimens seemed, however, to indicate contemporaneity by the apparent presence of pyroclastic materials in some portions of the limestone. The presence of limestones (even massive limestones) in the later Archeans is known; and until quite recently it was generally assumed in this country that they illustrate those extreme views of “regional metamorphism” so much in vogue, the metamorphism having been so complete in such cases as to have obliterated all traces of organic remains. In 1888 I challenged that view, on the 240 Correspondence—Major- General McMahon—Mr. Harker. ground of the much greater probability of a directly mineral origin of such limestones, as the necessary result of chemical reactions, which a common-sense application of known laws of thermal and general chemistry tells us must have taken place in the earlier (‘‘pre-oceanic”) stage of the history of our earth. This was put plainly enough before the geological world in my “ Metamorphism of Rocks” (Longmans, 1889), pages 6-16; and it is needless that I should do more now than refer the reader to that work, so far as concerns the theoretical bearings of the facts here narrated, MALVERN. A. Irvine. 13th April, 1892. REPLY TO PROF. J. F. BLAKE. Str,—There is only one point in Prof. Blake’s reply in your April Number that I intend to notice. Prof. Blake writes :— «‘General McMahon says he was considering capillary flow under heat and pressure, but in his paper he really only discusses the action of heat, and the present discussion on the effect of pressure is a new one.” This statement is really a very extraordinary one. In my paper in the GrotocicaL Magazine (February, 1892, pp. 74, 75). I simply refer to statements regarding pressure made in my original paper (Proc. Geol. Assoc. vol. xi. pp. 401, 482). In this last paper I showed that pressure was a very important factor, and I gave very interesting statistics at pp. 408, 439 (then published for the first time) supplied to me by an eminent engineer showing that in the case stated, the actual measured pressure at 190 feet below the surface, was equal to the calculated pressure, and was no less than 80 Ibs. on the square inch. I do hope for the future success of “The Annals of British Geology,” that Prof. Blake will devote a little more attention to the mastery of the papers he attempts to boil down. Unless he does so, T am afraid that his geological Bovril will not prove a very stimu- lating or nourishing article. 20, Nevern Square, C. A. McManon, Major-General. 10th April, 1892. CONE-IN-CONE STRUCTURE. Srr,—lIf Mr. Young’s statement! is meant to be of universal application, it is certainly not borne out by observation. A radial arrangement of the cones about a large nodule is, I believe, not an uncommon thing. Good examples occur in the Lingula Flags of Borth near Portmadoc, which contain flattened nodules, extending along the bedding, sometimes several feet long. Each is surrounded by a layer of well-characterized “ cone-in- cone,” and the apices of the cones are directed inwards towards the nodule, so that they point downward on the upper side, upward on the lower side, and horizontally on the edges of the nodule. I have noticed the same thing on a smaller scale in the shales of the Yorkshire Lias. Sr. Joun’s Conn. Camp. ALFRED HARKER. *,* The Editor regrets that, through inadvertence, this letter has been delayed in publication.—Eprr. Grou. Mac. 1 See Grou. Maa. for March last, p. 138. GEOL. MAG., 1892. 165, HMM Ws HG, IMG W/L To illustrate Mr. Hunt’s Paper on the Rocks of South Devon. Vol. [X., Plate VIT. Dec. ITT. GEOL. MAG., 1892. N To illustrate Mr. Hunt’s Paper on the Rocks of South Devon. THE GHOLOGICAL MAGAZINE. NEWie SERIES. | DECADE Ie VOL. 1x. No. VI—JUNE, 1892. ORIGINAL ARTICLES. I.—On Certain Arrinitics Between THE Devontan Rocks or SourH Devon anp THE Metamorpuic Scuists. By A. R. Hunt, M.A. Part I. (PLATES VI. anv VII.) N submitting the following paper to the readers of the GroLogi1caL MaGazinge, I am conscious that some apology is needed for entering upon so difficult a subject. My position is as follows :—In 1879 the late Mr. EH. B. Tawney joined me in the investigation of a series of detached blocks trawled from time to time by the Brixham fishermen. The character of certain of these stones having suggested to Mr. Tawney the idea that the schists of South Devon might possibly be of pre-Cambrian age,’ he visited the district in 1880, with the expectation of being the first to advance that hypothesis. The evidence of the schists themselves failed to satisfy Mr. Tawney on the point in question, and his premature death prevented his attacking the problem on a subsequent occasion, as he had hoped to - be able to do. On Mr. Tawney’s death in December, 1882, Prof. Bonney was good enough to take his place in supplying me with microscopic analyses of the Channel blocks. In the following Easter, a week spent among the metamorphic rocks of South Devon resulted in a paper published in the Quarterly Journal of the Geological Society, in November of the same year, in which Prof. Bonney expressed the opinion that the South Devon schists might be safely regarded ‘as Archean, and as a prolongation of the massif so distinctly indicated in the Lizard, to which also belonged the gneiss of the Hddystone,” Q.J.G.S., vol. xl. p. 23. It may be observed that the original investigation of the Channel blocks was undertaken for the purpose of elucidating, if possible, the Start and Bolt problem, and that my first paper was lent to Mr. Pengelly in MS. for use in preparing his own paper, “The Metamorphosis of the Rocks extending from Hope Cove to Start Bay.” The two were published in sequence at the Ilfracombe meeting of the Devonshire Association in 1879. In 1879 Mr. Pengelly maintained the Devonian age of the meta- ‘morphic schists. During 1880-82 Mr. Tawney reserved his opinion, 1 Trans. Devon Assoc. vol. xxi. p. 468. DECADE III,.—VOL. IX.—NO. VI. 16 242 A. R. Hunt—Devonian Rocks of S. Devon. having failed in his search for evidence of their pre-Cambrian age. In 1883 Prof. Bonney, without much hesitation, proclaimed the Archean age of these troublesome rocks. Under these circumstances there seemed nothing for me to do but to continue collecting facts, and to await the issue of events. In 1887, 1888, and 1889, Mr. A. Somervail published three papers in the Transactions of the Devonshire Association, in which he suggested that the chlorite schists might be the representatives of the Devonian diabases which appear on the coast line of Start Bay, and in the neighbourhood of Dartmouth. Early in 1891, Mr. W. A. E. Ussher was good enough to allow me to accompany him on two occasions when mapping the Devonian rocks between Dartmouth and Slapton Sands. Being much impressed by the many obvious analogies between these rocks and the meta- morphic rocks further south, I determined to examine and compare as many varieties of the two sets of rocks as I could obtain. My self-appointed task, then, has been to endeavour to ascertain what affinities, if any, can be detected between the metamorphic rocks of South Devon and the slates grits and volcanic rocks which lie to the northward of them; the green rocks being compared with the volcanics, the mica-schists with the slates, and the quartz-schists with the fine grits or sandstones. At first sight the quartz-schists and grits seemed the least pro- mising of the different rocks selected for comparison; but on Mr. Harker finding detrital tourmaline in one of the Devonian grits, and the same mineral being subsequently detected by myself in a quartz- schist from near Start Point, these siliceous rocks took a foremost place in the investigation. THE QuartTz-ScHIsts AND GRITs. A geologist examining the classical area of Devonian rocks which forms the northern shore of Torbay between Hope’s Nose and Hesketh Crescent, will not fail to notice the frequent interbedding of slates and grits (the latter often in bands too thin to be dignified by the name of sandstone), and that both rocks are often more or less micaceous. A slice of a brown sandstone from the quarry on the path east of Kilmorie is seen in the microscope to be composed chiefly of fine grains of quartz, of which the larger average about $5 inch in diameter, some of them being splinters with angles absolutely unaffected by attrition or solution; among these may be noticed an occasional flake of white mica, a few scattered fragments of tour- maline, and two or three grains of triclinic felspar. Another specimen from the same quarry is a fine hard lead- coloured sandstone bedded in well-marked laminz, which determine its fracture under the hammer; the surfaces of these planes of fracture being highly micaceous. The bands of grit between slates are sometimes crossed by quartz- veins which do not invade the adjacent slates. In the cliffs at the north-east end of Slapton Sands we meet A. R. Hunt—Devonian Rocks of S. Devon. 243 with slaty rocks with interbedded grit bands, in which latter mica is occasionally very conspicuous. ‘The rocks here are less generally micaceous than those between Hope’s Nose and Meadfoot in Torbay, but a reddish grit-band sliced for the microscope proved almost identical, except in colour, with the brown Kilmorie sandstone already mentioned ; even to a few grains of triclinic felspar. The cliffs at Torcross are passed unexamined, as there are some seven volcanic bands of more or less importance in them, and the sedimentary rocks in consequence liable to intermixture with volcanic ejectamenta. Just south of the village of Beesands some interesting grits occur, about the spot where Sir Henry de la Beche placed the boundary-line of the metamorphic rocks. Again we meet with fine sandstones and interbedded grits and slates, the sandstones and grits occasionally containing tourmaline and mica, like the rocks at the north-east end of Slapton Sands, and those in Torbay, already described. At a point on the coast, south of Start Farm and west of Start Lighthouse, among schists much crushed and altered, there occur occasional bands of quartz-schist, which in general appearance, in their constituents of quartz-grains, mica, and tourmaline, as well as in their intercalation between beds of a more slaty nature, recall to mind, both macroscopically and microscopically, the micaceous and tourmaline-bearing grit-bands of Torbay, Slapton Sands, and Beesands. The undoubted Devonian sandstones may be traced into the un- doubted metamorphic quartz-schists by four independent lines of inquiry, viz. by way of iron ores, tourmaline, mica, and quartz. Iron Ores. A slice of a grey micaceous sandstone (No. 5) from south of Bee- sands contains much brassy-looking pyrites crystallizing in cubes, rectangular prisms, and derivative forms.' The pyrites is occasion- ally seen to pass into red hematite. With strong oblique sunlight on the slide the characteristic colours of these minerals are well seen. A slide (No. 22) from a grit-band between slates on the north shore of Southpool Creek, not far from the metamorphic boundary, contains a minute rectangular prism of pyrites, and flakes of red heematite. In Hope Cove, south of Hope Headland, and therefore within the metamorphic boundary, a siliceous band occurs which, while showing no trace of its original quartz-grains, retains its pyrites in cubes and rectangular prisms.? The majority of these crystals display the brassy colour of pyrites, and occasionally characteristic striz are seen. In one group of twinned erystals, a crystal is composed partly of yellow pyrites and partly of bright red hematite—whether in this case the latter is a pseudomorph or only a surface incrustation is uncertain. In a slide from one of the slightly altered bands of quartz-schist south of Start Farm (No. 6) a cube of red hematite occurs which is 1 Plate VI. Fig. 3. ' * Plate VI. Fig. 4. >) 244 A. R. Hunt—Devonian Rocks of South Devon. apparently a pseudomorph after pyrites, as the latter mineral has not been noticed in either of my nine slides of these quartz-schists, whereas red iron oxides are abundant. Black granules and streaks, apparently magnetite, occur in all the above four slides, but as they in no instance exhibit the characteristic octahedral crystallization of that mineral, their evidence is only of minor importance. It is well worthy of notice that in three of these four slides, two being from the metamorphic district, and one from outside the boundary, we have pyrites intimately associated with hematite, either in the same crystal, or as a pseudo- morph; and further, that on either side of the boundary we find pytites crystallized in the somewhat uncommon form of rect- angular prisms. Tourmaline. Tourmaline has been noticed in ten slides from the following six Devonian localities, viz. quarry near Kilmorie, Torbay ; north-east end of Slapton Sands; cliffs south of Beesands ; grit band in Southpool Creek ; near East Charleton ; and Aveton Giffard : and in eight slides from two bands of quartz-schist on the coast south of Start Farm, in the metamorphic area. In every case the larger grains are clearly of detrital origin, the only exception being in one or two instances in the quartz-schist, where secondary tourmaline has crystallized on the original grains, and these secondary crystals have been swept to a distance by differential movements in the rock.! No alteration by pressure or solution has been observed in the tourmaline grains in rocks north of Beesands, the first indication noticed being south of that village. In a reddish grit containing much hematite (No. 59), a well- characterized light-brown crystal of tourmaline is broken sharply in two, and slightly dislocated. Clear quartz fills the intervening gap without in the least dissolving the edges of the tourmaline crystal.’ A grain of tourmaline in another slide from the same neighbour- hood (No. 5) is slightly, albeit distinctly, affected by solution, with indications of the re-crystallization of secondary tourmaline. In a slice (No. 16) of one of the quartz-schist bands south of Start Farm, two crystals of tourmaline may be especially noticed : one, a longitudinal section, with characteristic transverse cracks; the other a basal section. In each case there is a considerable growth of secondary tourmaline on the original crystals; and in each case also, by a slight differential movement of the rock, fragments of this secondary tourmaline have been detached and moved to a small distance from the parent crystal. We have thus close together in the same field of view detrital tourmaline and induced tourmaline.’ The origin of the latter would be obscure, were not all the steps of the process so clearly set forth, ‘Tourmaline occurs in many forms and colours; but the tourmalines of Beesands and the Start coast are identical. 1 Plate VI. Fig. 2. * Plate VI. Fig. 1. _ 3 Plate VI..Fig. 2. A, JE Wigs “idenatan ads of S. Devon. 245 Quartz-grains. The quartz-grains in the sandstones north of Beesands do not call for particular notice. Just south of Beesands we have seen quartz filling the interstices of a broken tourmaline, and in another case a grain of tourmaline slightly affected. Professor Bonney’s description of a rock from the same locality seems exactly to cover the case, viz.: “The rock has evidently been much compressed, and some slight amount of mineral change has taken place” (Q.J.G.S. vol. xl. p. 18). An occasional quartz-grain contains liquid inclusions and bubbles, but without any distinguishing features. A slide of a Devonian grit-band trom Southpool Creek (No. 22) contains more than one quartz-grain of interest. One grain showing considerable solution at the edges abounds in hair-like inclusions together with an occasional fluid inclusion with bubble. Another grain is crowded with fluid inclusions, some of which contain very active bubbles, while others take the form of negative crystals. In a slide (No. 8) cut from the specimen of quartz-schist from Start Farm, given me by Mr. A. Somervail, we find a quartz-grain with hair-like inclusions; and in another slide from the same stone (Ne. 10) we have a grain with bubbles in negative crystals. These two grains resemble the two in the Southpool Creek slide already referred to. However, the most interesting feature in the quartz-schist lies in the fact that the rock has not been submitted to pressure and heat sufficient to obliterate entirely the original tourmalines and quartz- grains, and that a comparison with the sandstones and grit-bands of Beesands and Southpool Creek is still possible. In the case of the quartz-schists at the Bolt Head, further west, tourmaline is absent, and the obliteration of original structures in the quartz is complete; thus a comparison with the Devonian sandstones on this particular point is not possible. Mica. On first collecting the Devonian micaceous sandstones for com- parison with the Start schists, the possibility that the mica in either case might be detrital had not been entertained. On Mr. Harker pronouncing the Slapton Sands mica detrital,! and that in the Start quartz-schists possibly so,? the origin of the Devonian and metamor- phic micas became a problem of importance. If the metamorphic rocks were micaceous before their alteration, the presence of much of their mica might be accounted for with much less dynamical and chemical metamorphosis than is at present demanded for them. In the case of the sandstones and quartz-schists, it is easy to find Devonian sandstones much more highly charged with mica, than the Start quartz-schist under consideration, in which, as Mr. Harker remarks, the mineral is only sparingly present, e.g. the sandstones and grit bands of Kilmorie, Meadfoot, Slapton Sands and Beesands, 1 Appendix, Slide. No. 3. 2 Appendix, Slide No. 8. 246 A. R. Hunt—Devonian Rocks of S. Devon. to go no further a-field than the coast-line. Both the sandstones and quartz-schists contain mica varying between the minutest filmy flake, hardly seen in the microscope, and flakes sufficiently apparent to the naked eye. Given a small amount of solution in the silica of the quartz-grains, so that the mica flakes might be free to partially rearrange themselves, and there seems to be no reason why the Start quartz-schist under consideration should not have been derived directly from such a rock as the Kilmorie sandstone, without any development of newly-formed mica. So tar as I understand it, a theory held by some is that the Devonian slates and sandstones when micaceous are with very few exceptions “ Phyllites,” in which the mica is considered to be an induced product; and that the mica-schists are rocks in which the mica has also been induced but to an incomparably greater extent, so that the rocks differ in kind. It seems, however, possible, that the converse of this may be true, and that with some exceptions the mica in both the Devonian and metamorphic rocks is, or was, originally, detrital, the deposition of micaceous sediment being much more general in the southern area than further north. Irregular deposition is occasionally exemplified in the Torbay rocks, in which worni-tracks in slates are filled with fine micaceous silt. In the foregoing pages the iron ores, tourmaline, micas, and quartz-grains of the Devonian sandstones have been connected with the iron ores, tourmaline, micas, and quartz-grains of the meta- morphic quartz-schists. It cannot be doubted that were the rocks further examined by a competent mineralogist, other points of re- semblance would be noticed, for minute grains of felspar, unless well defined, and the rarer minerals, are beyond the power of my microscope and knowledge to distinguish. One noticeable feature which the grits and quartz-schists possess in common is the abundance of laminz of iron oxides: at Hope’s Nose, black; at Kilmorie, brown; at Slapton Sands, red; at Bee- sands, black and red; at the Start, black and red. The colours being probably due to the brown, red, and black, oxides of iron. The following remark of M. Daubree is worth noticing, although the black oxides of the Start schists do not take the form of crystallized magnetite :— ‘Dans certaines localités des Ardennes, les cristaux de fer oxy- dulé, qui imprégnent les ardoises se sont logés suivant les longrains, et font ainsi ressortir des joints rudimentaires qui, ailleurs, ne sont pas reconnaissables & la vue.”—Geol. Experimentale, vol. i. p. 336. At the Start we find the quartz-schist traversed by numerous little cracks cemented by opaque iron-ores. Tue Mica-Scutsts AND SLATEs. The mica-schists of the metamorphic district, as distinguished from the schists in which quartz is the most prominent mineral, have not been examined to any extent. One specimen of a red schist, which I thought might compare with the red Devonian slates, is described by Mr. Harker as a rock W. A. E. Ussher—Permian in Devonshire. 247 which “may have been originally a shale or slate with some gritty bands.”! Mr. Harker could not have more precisely described the cliffs at the north-east end of Slapton Sands, with whose shales or slates I desired to connect the red mica-schist from the Start, had he been intimately acquainted with the locality instead of being a perfect stranger thereto. Enp oF Part I. EXPLANATION OF PLATES VI. anp VII. Puare VI. Fre. 1.—Crystal of tourmaline in fine Devonian Sandstone, four chains south of Beesands. (59) Magnified about 37 diameters. Fic. 2.—Crystal of tourmaline in quartz-schist, Start Farm. Formation of secondary tourmaline with partial dislocation of same. (16) Mag- nified about 37 diameters. Fie. 3.—Rectangular iron pyrites in fine Devonian Sandstone, north of Tinsey Head. (5) Magnified about 18 diameters. Fic. 4.—Rectangular iron pyrites in siliceous band, South of Hope Headland. (52) Magnified about 18 diameters. Puate VII. Fie. 1.—Quartz-schist, Start Farm. Remnants of original quartz grains. (Compare “ Grain of Quartz-sand in the Mica-schist of Arroquhar.”’ Presidential Address of Dr. Sorby, F.R.S., Proc. Geol. Soc. 1880, p- 86, Fig. 9.) Magnified about 12 diameters. Fie. 2. Fine Devonian Sandstone, north of Tinsey Head, with schist-like alinea- tion of iron ores and greenish mica. Magnified about 12 diameters. T am much indebted to my friend Mr. W. M. Baynes, of Torquay, for valuable assistance in the preparation of my photographs for publication. (To be continued.) IJ,—Permian 1N DEVONSHIRE. By W. A. E. Ussuerr, F.G.S., Ere. (By permission of the Director-General of the Geological Survey.) N the course of a visit to the Hunsruck district between Treves and Bingen in the spring of 1890, in company with Professor Gosselet, Mons. C. Barrois, Herr von Reinach and Herr Grebe, I was struck by the resemblance displayed by the Permian quartz porphyry of the valley of the Nahe, between Birkenfeld and Bingen, to fragments contained in the breccias of Teignmouth. In discussing the South Devon section with the two gentlemen last named, on that occasion, they both gave it as their opinion that the lower beds of the Devon section might prove to be representatives of the Rothliegende. In the pressure of other geological work, I had no time to carry the matter further, until May, 1891, when Herr von Reinach spent a week with me in examining the South Devon coast section and the eruptive rocks in the vicinity of Hxeter and Crediton. He then expressed the opinion that certain parts of the lower New Red rocks of Devon corresponded very closely with members of the German Permian, but that this correspondence was not borne out in con- 1 Appendix, Slide 24. 248 W. A. BE. Ussher—Permian in Devonshire. secutive horizons. In the Teignmouth breccias with numerous fragments of claystone porphyry, quartz porphyry, etc., he detected a strong resemblance to the Rothliegende (Upper Sodterner) of the Nahe, above the volcanic horizon (Grenz schichten). In the Voleanic rocks of the Exeter and Crediton areas he recognized the equivalents of the Grenz schichten (Middle Soterner). Herr von Reinach also pointed out to me the similarity presented by some of the thick even- bedded red and whitish sandstones intercalated with marls to the east of Exmouth, to the Upper Bunter Sandstones of the Moselle, recalling to my mind sections I had seen near Treves and in the Hifel. On the 10th of last February Herr von Reinach wrote me as follows :—“ Professor Biicking had the kindness to determine the melaphyres and tuffs I brought with me from the environs of Exeter. As I do not intend to publish these facts, I authorize you, also in the name of Professor Biicking, to make use of this communication. You know that we have at the Nahe—(1) Melaphyres in the Older Rothliegende which are only intrusive; (2) Melaphyre Covers (Melaphyr decken) which we have only in the Sdterner (Grenz schichten) of the Rothliegende. The Grenz Melaphyre has been divided by Lossen into Upper, Middle, and Lower, which types are generally the same throughout the Nahe district.” Prof. Biicking’s identifications are as follows :— Spencecombe, Knowle Hill (Crediton Valley) { eee ae oe Posbury, near Crediton : war Pocombe, iearalineten Melaphyr with Olivine. Dunchideock, between Exeter and Chudleigh.—Melaphyr with Olivine and Bronzite. Yeoton, near Crediton.—Tuff. Herr von Reinach adds: ‘The Dunchideock Melaphyr is identical with our type of the uppermost Melaphyr roof zone (Dach zone) of the environs of Kreutznach on the Nahe.’” Although the detailed mapping of the eruptive rocks associated with the New Red of Devon was completed about fourteen years ago, I have published nothing specially on that subject, certainly not from lack of materials. In 1876 Mr. Rutley visited all the chief localities with me, and determined the rock for the Geological Survey; these determinations have been lately confirmed by Dr. Hatch, and they agree with the determinations of Prof. Biicking; of this Herr von Reinach was not aware, but the fact rather enhances than lessens the importance of the communication he has so kindly authorized me to impart. If we assume the correlation of the New Red volcanic rocks with the Grenz-schichten as established, the probable correlations with the Nahe section might be as follows :— Dawlish breccias x... ... ... 4s, “Ss. see se ~Upper Rothliesende: Teignmouth breccias... ... «4. «4. see «+» ) Lower Rothliegende. Basalts (local)... .. .. sae wes nee eee ? (Sterner beds with Watcombe and Petitor conglomerates... ... -- volcanic rocks). It must, however, be borne in mind that no correlations framed on a partial, or even intimate acquaintance with the South Devon coast W. A. E. Ussher—Permian in Devonshire. 249 section only, can be regarded as conclusive. The local clusters of voleanic patches from Exeter northwards may not be on the same horizon. As regards the Bunter, if we assume the Straight Point (east of Exmouth) Sandstones to be Upper Bunter, this probable correlation favours tbe Middle Trias age assigned to the Lower Marls in 1878. No evidence has been adduced to invalidate my classification of the Keuper from the Pebble beds of Budleigh Salterton upwards. I may say that Mr. Geo.’ Spencer Perceval, in three letters to the ‘“‘ Western Morning News” in 1877 or 1878 (I forget which year), disputed my classification of the Budleigh Salterton Pebble bed in the Keuper, maintaining that it represented the Bunter Pebble beds; this naturally deprives Prof. Hull’s recent communication to the Geological Society of the charm of novelty for me. My old friend Mr. P. O. Hutchinson, of Sidmouth, in 1878, found remains of an Equisetum-like plant in greenish shaly sandstone in the lower part of the Keuper Marls near Sidmouth ; this occurrence suggests a possible comparison with the “ Schilf (Reed) sandstone ” of the Middle Keuper of the Hifel. But an Equisetum (EH. Mougeotz) occurs in the Upper Bunter sandstone of the Hifel as Herr von Reinach informs me, so that no reliance can be placed on this suggestion. I take this opportunity of recording the recent dis- — covery (a few months ago) of quartz porphyry giving place upwards and outwards to a rock resembling a mica andesite and identical with specimens from one of the volcanic patches associated with the New Red of the Crediton Valley. This discovery was made at the eastern termination of the Thurlstone New Red Outlier. In connexion with it I quote the following passage from my paper’ before referred to :—‘“‘ The breccias frequently contain igneous frag- ments distinctly referable to the destruction of such igneous patches as those of Washfield, Kellerton, etc. The outflow of these lavas seems generally to have accompanied or heralded the earliest deposi- tion of Triassic sediments in the districts in which they occur ; nor does it appear impossible that the eruption of quartz porphyries may have been in some way connected with their appearance.” The late Professor Ramsay inspected the New Red Rocks in 1880, and failed to find any sufficient proof for the correlation of the lower breccias with the Permian of the Midlands. There is not a shred of proof that the two areas were connected until the Keuper, and probably at a late stage in that period. The Midland sections owe their importance as a basis for correlation entirely to the merits of the assumed correctness of their classification with reference to the German types. For much information on the characters of the German types I am indebted to my friend Herr von Reinach, whose acquaintance with them is most intimate. Until I have the oppor- tunity of availing myself of his kind offer to show me the rocks on the ground, or until new facts are brought to light in Devon, I fail to see that the literature of the New Red Rocks of Devon and West 1 Quart. Journ. Geol. Soc. for Aug. 1878, p. 462. 250 H. H. Howorth—The Mammoth and the Glacial Drift. Somerset,’ supplemented by the present communication, will be benefited by the addition of more speculative correlations. My friend Dr. Hatch has kindly sent me the following notes on specimens of the New Red Volcanic rocks of South Devon. Notes on Sliced Specimens of the Exeter “ Traps,” in the Collection of the Geological Survey at Jermyn Street. Olivine-basalt or melaphyre, composed of lath-shaped -striped felspars and scattered grains of magnetite, with calcite, replacing augite, and ferruginous pseudomorphs after olivine. Localities: Raddon Court (No. 951), Pocombe (No. 958), between Chiphele and Budlake (No. 958), and Quarry near Crabtree, Kellerton (No. 945). Porphyrite (Andesite): A felted aggregate of lath-shaped and microlitic striped felspars, with occasional porphyritic crystals of plagioclase. Localities: Western Town, Ide (943), Quarry N.E. of Knowle, N.E. of Holecombe-Burnell (946), and Knowle Quarry, W. of Dunchideock (949). The last two, with rounded (corroded) grains of quartz. Mica-porphyrite (Mica-andesite or trachyte).— Finely vesicular rocks containing brown mica, imbedded in a minutely microlitic ground-mass, which is generally rather obscured by the presence of dusty magnetite and secondary calcite. Localities: Kellerton Park (Nos. 944, 947 and 950). The nature of the felspar in these rocks is indeterminable, but specimens from Copplestone (Nos. 957 and 959) consist of a holocrystalline aggre- gate of broad lath-shaped crystals of orthoclase, flakes of brown mica and magnetite. IIJ.—Dip tHe Mammora hive Berore, Durinc, or AFTER THE Deposition OF THE DRIFT, By Henry H. Howorts, M.P., F.G.S., etc. is recent papers which I have printed in the GroLocIcaAL Magazine I have tried to show that some of the greatest mountain chains in the world are of very recent origin; and that this accounts for their showing no traces, or very slight ones, of the action of ice on a wide-spread scale. I have, in fact, ventured to lay down the conclusion that the presence or absence of such traces of ice-action is a test of whether these mountains existed at the so-called Glacial period or not. If my view be right, it follows that very large masses of land were thrown up suddenly or very rapidly in post-Pliocene times ; and, if this was so, it is very probable that there was a great sub- sidence of land in other parts corresponding to this upheaval. I believe that this can be proved, and that it involves some important 1 Go. Mac. for April, 1875; Quart. Journ. Geol. Soc. Aug. 1864 ; February, 1870; Nov. 1876; Aug. 1878; Transactions of Devonshire Association, 1877, 1878, 1881; and the Proceedings of the Somersetshire Archeological and Natural History Society for 1889, vol. xxxv. Hl. H. Howorth—The Mammoth and the Glacial Drift. 251 and interesting considerations worth discussing. Before we can deal effectively with this problem, however, we must settle another one equally important and equally interesting, to which I propose to devote a few pages, namely, the precise geological horizon where we are to put the Mammoth and his companions, including Paleo- lithic man. It is at once a reproach to geology, and a good proof of the very great difficulty there is in making our way among the latest geological records, that there should be any doubt upon such a question. The fact is nevertheless so, and has given rise to a sharp polemic elsewhere in quite recent years. I am bound to say that I myself have changed my views on the subject in view of the evidence, and have to recant some phrases I once printed in this MaGazine. I wish to speak with some precision in the matter, and not to be misunderstood. The point 1 would discuss is not whether the Mammoth lived before, during, or after the so-called Glacial period, but whether the beds in which his remains are found, when undis- turbed, underlie or overlie the Drift, or are intercalated with it. The two questions are not, as is often assumed, the same, and it is to the latter alone that I wish my criticism to apply. I must also define the kind of evidence which I alone think con- clusive. I altogether distrust any evidence on the point except that of superposition. Hvidence based upon inferences of different kinds I have always mistrusted in deciding this critical question, but I would go further. We must remember that the Till or Boulder-clay con- tains extraneous bodies of different kinds, which are often far- travelled, and sometimes not so. Among these bodies there may be tree-trunks or molar teeth of Elephants, which may be as true boulders as those of granite and gneiss and like them derived from elsewhere. Whatever theory we adopt in regard to the Till, we must concede that it picked up far-travelled débris in its march, and mixed it in many cases with the débris of the underlying beds, ‘sometimes with Chalk, sometimes with Lias, sometimes with sand- stone and mixed this débris with the fossils from these different beds. It is further clear that ice would take up and convert Mammoth teeth into boulders just as readily as Ammonites and Belemnites, and that the former would be no more contemporary ‘with the Till nor evidence of an interglacial climate than the latter are. Let us now turn to the evidence. The earliest discovery of Mammoth remains in Scotland took place in the year 1817. “When,” says Sir A. Geikie, “the Till covering the sandstone at the quarry of Greenhill in the parish of Kilmaurs, in Ayrshire, had been partially removed, there were found at a depth of 174 feet from the surface, two Elephant’s tusks. . . . The matrix in which they were found was aclay, which around the bones changed from its usual light brown colour into a dark brown, with a most offensive smell when turned over. ‘The tusks lay in a horizontal position with several bones near them. Dr. Scouler visited the quarry about 1840, and reports that seven 252 H. H. Howorth—The Mammoth and the Glacial Drift. more tusks had subsequently been found there (Trans. Geol. Soc. Glasgow, vol. i. pt. 2, pp. 68-69). Some antlers of the Reindeer were also found along with an Elephant’s tusk at this quarry (id. p. 71). These remains were found in a clay containing, inter alia, Astarte compressa and Leda pygmea, with eight genera and nine species of Foraminifera, and five genera and ten species of Ostracoda, and also a number of seeds of plants and fragments of beetles. The earlier writers described this clay as Boulder-clay. Dr. Bryce, in 1864, opened some pits at the place, and found that the beds in which the remains occurred underlie the Till, and he put them on the same horizon as the Forest Bed. Mr. Craig and Mr. Young, in 1869, after a close examination of the district and the position of the beds in regard to the Boulder-clay, satisfied themselves that the Mammoth and shell-bed were pre-Glacial (see Trans. Geol. Soc. Glasgow, vol. iii. p. 810). The officers of the Geological Survey in their com- mentary on Sheet 22 describe the bed as inter-Glacial; but after sifting the evidence again, and writing in 1887, Mr. Craig says: “JT see no cause to change the conclusions arrived at in our joint paper of 1869.” Dr. Bryce’s surmise that the fossiliferous bed may be the equivalent in age of the Cromer Forest Bed is, in my opinion, not far from being correct. Elsewhere he says he places the beds at the very base of the Glacial deposits (Trans. Geol. Soc. Glasgow, vol. vili. pp. 2138-223). According to Mr. J. Geikie, these remains ‘‘ occurred in a peaty layer between two thin beds of sand and gravel, overlaid by Till or Boulder-clay, and resting directly on the sandstone rock of the quarry” (Great Ice Age” p. 605). A horn of a Reindeer was also found in the basin of the Endrick, in the parish of Kilmarnock, about four miles from Loch Lomond. “The section in which it occurred,” says Sir A. Geikie, “ consisted first of the vegetable mould, then of a stiff clay 12 feet thick, containing a large quantity of stones, underneath which was a bed of blue clay about 7 feet thick, at the lower part of which, close upon the underlying sandstone, the antler was found, and near it a number of marine shells. The deposit was estimated to be about 100 to 103 feet above the sea-level” (Trans. Geol. Soc. Glasgow, vol. i. pt. 2, pp. 70, 71; see also Dr. Smith, Edinb. New Phil. Journ. n.s. vol. vi. p. 105). The next locality where Mammoth remains occurred in Scotland was during the excavation of the line of the Union Canal, between Edinburgh and Falkirk. This was in 1820. A large mass of Boulder-clay having been undermined fell into the cutting, and among the earth was found a tusk measuring 89 inches in length. It had lain about 15 or 20 feet from the surface. Mr. Bald, to whom the discovery was reported, examined the place. He says it was found from 15 to 20 feet from the surface. He did not actually take it out of the clay, and only judges that it must have come out of it from its excellent state of preservation (Wernerian Society, vol. iv. p. 60). It has subsequently been described as having been imbedded in the heart of the stiff clay. If it had been so, it can H. H. Howorth—The Mammoth and the Glacial Drift. 258 only be treated as a boulder, since it was quite detached ; this is suggested by Mr. Bald, and it in no way evidences an old land surface; but it seems to me there is no warrant for describing it as having come out of ‘the heart of the stiff clay.” A skull of Bos primigenius was found in 1868, near Croft Head in Renfrewshire, imbedded some few feet deep in a soft clay or mud, interlaminated with lines and beds of sand, and occasional layers of fine gravel. In some of the layers of clay there was a little vegetable matter in a state of decay. These beds were overlain by Till full of scratched stones (Geikie, Grot. Maa. Vol. V. p. 398, etc.). In a paper on this deposit, in Vol. VII. of the same Macazinez, Mr. Geikie says that it subsequently yielded remains of the Horse and Irish Deer. He reaffirms the opinion that the overlying clay in this instance is the true Boulder-clay, that it is in situ, and in no sense due to a landslip. On the 6th of March, 1879, there was exhibited before the Geological Society of Glasgow a well-preserved molar of a Mammoth found four years before in sinking a pit on Mainhill Farm, near Baillieston, east of Glasgow. It was found in a bed of purely laminated sandy clay, at a depth of 33 feet below the present land surface, the sand bed being from 40 to 45 feet thick, and resting directly upon the rock-head or Coal-measures without any inter- vening Till or other superficial strata. In cutting the line of railway leading to the pit, the sand bed was seen to be overlapped by a thick bed of stiff dark-coloured Boulder-clay full of large travelled stones, which thinned away as the pit was approached, and the sand bed rose to the surface. Mr. Young remarked that here we had another instance of the occurrence of the Mammoth in Scotland, during pre-Glacial times, and he went on to remark that in all the cases which had occurred in Scotland, the Mammoth remains he says ‘had either been derived from pre-Glacial beds below the Till or from the Till itself. Dr. Geikie has never been able satisfactorily to show that the Mammoth-bearing inter-Glacial beds, in any of the places where they have been found, rested on an older Boulder-clay, although he says that at other spots, such as Kilmaurs, intercalated beds are found in the same district between the two Tills; but unfortunately for his contention, these beds have never as yet yielded any Mammoth remains, nor any of the other organisms found associated with them. When traces of the Mammoth have been got in Boulder-clay, they may in all probability have been derived from the denudation of pre-Glacial beds in the same district ” (Proc. Geol. Soc. Glasgow, 1878-9, p. 291). In January, 1882, there was exhibited before the Glasgow Geol. Soc. a fragment of a tusk of the Mammoth which had been found in sinking a pit on the farm of Drummuir, Dreghorn. This was found in a bed of sand underlying 16 feet of Boulder-clay (Trans. Geol. Soc. Glasgow, vol. viii. pt. ii. p. 218, ete.). In a paper by Messrs. Craig and Young, in the third volume of the Trans. of the Geol. Soc. of Glasgow, they say, inter alia, that if we look at the recorded instances of the occurrence of the Mammoth 254 HH. H. Howorth—The Mammoth and the Glacial Drift. and Reindeer in Scotland, we shall find that in the majority of cases they either have been found in beds below the Boulder-clay or in that deposit itself. Those found in the Boulder-clay may have been derived from the denudation of pre-Glacial beds. In the one or two instances where the Mammoth has occurred in beds more recent than the Till, they may still have been worked out of it. Bearing on the pre-Glacial age of the Reindeer in Scotland, they refer to a portion of the right antler of a Reindeer found in the Boulder- clay at Raes Guill, Carluke, Lanarkshire. ‘‘The specimen bears evident marks of transportation, its burr, browtyne, and other extremities being worn and rounded, and the whole surface has a smooth, polished, ice-scratched appearance, exactly like that we meet with amongst the ice-worn stones of the Till. It was found in Till several feet thick” (op. cit. pp. 810-520). Let us now turn to England. No remains of Pleistocene mammals: have occurred so far as I] know in the counties of Northumberland, Durham, Cumberland, or Westmoreland. Of the few cases of the discovery of Mammoth remains in Lancashire and Cheshire, the only one, according to my friend Prof. Dawkins, in which the relation of the deposit to the Boulder- clay is clear, was the famous case of the discovery made by Mr. Bloxsom in March, 1878, in digging a shaft for the new Victoria Salt Co. near Northwich, of a fragment of a molar. It occurred at a depth of 65 feet in a bed of sand overlying the red Keuper marls, and overlaid by 87 feet of brown Boulder-clay (Q.J.G.S. Feb. 1879, pp. 140-141). If we turn to Yorkshire, the evidence is more abundant and more conclusive. In a Memoir on the Moors, Mountains, and Sea-Coast of York- shire, published by J. Phillips in 1858, he urged that the lowest Hessle gravels, which rest upon Chalk, and are covered by Boulder- clay, as well as the contents of Kirkdale cave, are pre-Glacial. Writing in 1868, he says of this view about the Hessle gravels: “I am still disposed to favour this opinion ; in the first place, there is no proof that these beds are marine, but a strong presumption to the contrary, from the considerable abundance of land Mammalia found in them, especially Elephas primigenius and Horse; and secondly, beds of this order composed of chalk and flint fragments, not only are not known to occur in the midst of the Boulder-clay, but can hardly be imagined to exist there; and, thirdly, the Boulder-clay rests on them without conformity (Q.J.G.S. vol. xxiv. p. 255). Phillips continued during half a century to be the advocate of the Mammoth beds being older than the Drifts, and in the last edition (1875) of his Geology of Yorkshire, in describing the ossiferous marls of Bulbecks, near Market Weighton, shows that they lie directly on the red marls; and in regard to their relative age, he says: “It appears to be proved, both by comparison with the analogous deposits at Hessle and Bridlington, and by the super- position of the ordinary diluvium in the south-eastern part of the Vale of York, that the latest of these inundations (7.e. that which H. H. Howorth—The Mammoth and the Glacial Drift. 255 laid down the Mammoth beds) was anterior to the movement of waters which brought many Cambrian rocks through the pass of Stainmoor and dispersed them over the hills and valleys and ante- diluvial lake deposits of Yorkshire” (op. cit. pp. 12-19). Speaking of the Hessle beds containing Mammalian remains, he says: “As they are now covered up by a great thickness of clay and pebbles derived from a far greater distance (¢.e. by the Drift), we count them the spoils of pre-Glacial land” (id. pp. 57, 58). Teeth of Mammoths sometimes occur in the Boulder-clay in Yorkshire as they do elsewhere, but are clearly derivative and boulders. Phillips has remarked how in certain places only the teeth occur, and no other parts of the skeleton (7d. p. 74); when bones occur under these circumstances, they are always scattered and generally rolled (id. p. 170). In regard to the deposits in Kirkdale cave, he points out their analogy with those occurring at Bulbecks, ‘where glacial drift overlies the bones,” adding ‘“‘that Kirkdale cavern was occupied in the pre-Glacial condition of the land which is now Yorkshire was my earliest opinion, and seems still to be the most probable inference in the present state of knowledge” (id. 169-171). This opinion about Kirkdale cavern is interesting, for the evidence is fast accumulating to show that the cavern deposits at all events are older than the distribution of the Till. I should like to refer to another northern cavern, where, although no Mammalian remains occurred, there seems to have been a very decided invasion of Drift. Speaking of the cavern at Stainton-in-Furness, Mr. Cameron says: ‘‘The floor of a gallery resembles the bed of a dry mountain torrent, being strictly strewn with water-worn pebbles and boulders. Soft yellow clay occurs, frequently also gravel; while again in other places there is a pavement of hard dry clay split up by cracks into octagonal-shaped masses. . . . In this gallery are also Silurian boulders, often cemented together in huge masses. A few of these boulders are of a larger size than to have allowed of their entrance through the as yet only known inlet to the place. Ireleth, about 43 miles off, is the nearest place where this rock is in situ, and boulders and fragments of rock are often met with, thrown against each other in the direst confusion as if impelled along by a very strong current and suddenly stopped” (Grnon. Mace. Vol. VIIL. pp. 312, 313). We wiil now turn to the famous Victoria Cavern, where a considerable polemic arose in regard to the interpretation of the facts. It must be remembered that this discussion was before the more recent discoveries of Dr. Hicks, etc., in North Wales. Prof. Dawkins, who took the view in the paper that the remains in this cave were post-Glacial, says in the discussion that he could not say whether the Victoria Cave was pre-Glacial or Glacial, nor even define its relation to the Glacial period. The age of the clays was, he said, a matter of opinion (Q.J.G.S. vol. xxxiii. p. 612). Other explorers of the cavern were much more emphatic in their view. Mr. Tiddeman, who drew up the report to the British Asso- 256 H. H. Howorth—The Mammoth and the Glacial Drift. ciation, distinctly refers the deposit to a pre-Glacial age, and speaks of the Craven savage as having lived before the Great Ice-sheet (Rep. Brit. Assoc. 1875, p. 173). In a paper on the Cave by the same author, he tells us how a bed of tenacious clay with scratched Silurian and other boulders was found underneath all the talus at the mouth of the cave, resting on the edges of the beds containing the older mammals, and dipping outwards at an angle of 40°. Mr. Tiddeman explains this as the remnant of a moraine (lateral or profonde) which dammed up the mouth of the cave and prevented anything but water charged with fine sediment from entering it during the Glacial period. Perhaps, he adds, one of the strongest pieces of evidence, that the older cave animals lived in this district only at a time previous to the great ice-sheet, is that, so far as we know, the remains of none of them (except of Cervus elephas) have ever been found in any of the post-Glacial deposits of this district. Though so common in the river gravels in the Midland and Southern Counties, they are never found except in caves until we get much further south or east. Leeds is, I belive, the nearest locality where they occur. This would seem to imply that their remains were wiped off the area by the great ice-sheet, . . . and only left in the shelter of caves to which it could have no direct access” (GEon. Mac. Vol. X. p. 15). Writing in ‘“ Nature,” the same geologist says, ‘‘A human bone or fibula was certainly found beneath glacial clay in the Victoria Cave” (Nature, vol. xiv. p. 505). A dispute arose afterwards as to whether the fibula was human or not, but this does not affect the issue we raise. Mr. Tiddeman again says, “In the Victoria Cave the sur- roundings are such that nothing but an ice-sheet could have sealed up with glacial clay the remains discovered by the Committee. . . . The origin of the boulders, their position, the ice-scratches on the rocks hard by, all point to the time of greatest glaciation, when the whole district was covered in with ice and snow of great thickness. And the agent which closed the cavern and concealed the animals within it must have been the same which swept the country clean of their remains all around further than the eye can reach” (7b. 506.) In the discussion on Prof. Dawkins’ paper, Sir A. Ramsay said he thought the evidence for the existence of Man in the Victoria Cave before the Glacial period was stronger than that against it. Prof. Prestwich thought the deposits in the Victoria Cave were pre-Glacial (Q.J.G.S. vol. xxxili. p. 612). The next case to which I shall refer is one in which we have not to deal with Mammalian remains, but with the Southern freshwater shell the Cyrena fluminalis, which marks the Pleistocene horizon in other places. In 1861 Professor Prestwich read a paper before the Geological Society of London on the occurrence of Cyrena fluminalis over beds of Boulder-clay near Hull. He says there was previously no evidence of direct superposition to show the age of the shell. I quite agree with him that for this reason the instance in question is important if maintainable. Is itso? In the first place in the pit where the H.. H, Howorth—The Mammoth and the Glacial Drift. 257 Cyrena occurred in thousands, and of which Mr. Prestwich gives a section (Q.J.G.S. vol. xvii. p. 450), no Boulder-clay at all occurred. Secondly, in another section at Paull Cliff, near Hull, where the Cyrena also occurred in fewer numbers, there was an underlying clay, but Prestwich admits that inasmuch as it contained neither boulders nor fossils, he could not feel certain about its being the Boulder-clay ” (id. 452). Mr. Prestwich then had some experi- mental borings made, but they did not succeed in piercing the gravel, and therefore, in his own words, “failed to obtain the exact proof” (id. 453). Hence the evidence as tested by this locality utterly fails. Now it is curious that while Mr. Prestwich failed to find Boulder-clay in a definite position in regard to the gravels, Messrs. Wood and Rome did, and they say: “The gravel of Kilscar Hill, the subject of the notice of Mr. Prestwich, is (now that the ballast pit has been more extensively worked) shown most distinctly to be overlain by the Boulder-clay, no less than 15 feet of it being so exposed in one part; and they add that there are no means of ascertaining at present on what it rests (Q.J.G.S. vol. xxiv. p. 153). Let us now turn to the evidence of the Mammals. This also seems to be very conclusive. I will first refer to the well-known memoir by Mr. C. Reid on the Geology of Holderness. In this memoir, chaps. v. and vi. are headed “ Inter-Glacial Beds.” I do not know why, for I confess I can find no evidence of their inter- Glacial character. That is, however, another issue. Mr. Reid objects, on the evidence of the fossils, to Professor Phillips treating the Hessle gravels as pre-Glacial, an argument in which I do not quite follow him. He admits that at Bridlington they rest directly on the Chalk (op. cit. p. 48), that is, have no Boulder-clay or trne Drift below them. There some Mammalian remains have occurred in a buried cliff, which has since been very carefully examined by Mr. Lamplugh, to whom I shall refer presently. His conclusion that this bed underlies the basement bed of the Glacial series is confirmed by an observation of Mr. Reid, who says, that a similar bed of chalk-gravel, in borings at Bridlington Harbour, rests on the Chalk, and is clearly beneath the Basement clay (id. p. 49). Turning to the Hessle Mammaliferous gravels on the Humber, Mr. Reid admits that they also unmistakeably rest directly on the Chalk, and are covered and overlapped by Boulder-clay. Yet he goes on to argue that “we have nothing to fix the age of the Hessle gravel by, and that there is no positive evidence whether another underlying Boulder-clay has been denuded or not.” If so, why call the bed inter-Glacial? And he goes on to say, “ Prof. Phillips’s reference of the Hessle gravels to a pre-Glacial period may turn out, with fuller evidence, to be well founded.” JI should have said that it was conclusively proved, there being against it no stratigraphical facts, but merely an @ priori prejudice based on some theory about the fossils. A similar bed, but without fossils, at South Ferriby Cliff, on the south of the Humber, also rests on the Chalk, and is overlain by Boulder-clay. DECADE ilI.—VOL. IX.—WNO. VI. 17 258 S. S. Buckman—On Ammonites Jurensis. Tn regard to the marine gravels in which Professor Prestwich found the Cyrena fluminalis, and which have yielded many Mammalian remains, Mr. Reid admits that at one spot, at Kelsey Hill, a face of about 12 feet of weathered Boulder-clay, with small stones, can be seen overlying the gravel (id. ps 54). Mr. G. W. Lamplugh, in his paper on the Drifts of Flamborough Head recently published, is most clear on the subject. He describes the buried cliff at Sewerby as having been formed by marine action prior to the deposition of any of the Glacial beds, and as having afterwards been buried and obliterated by the accumulation of materials banked against it (Q.J.G.S. vol. xlvii. p. 394). In a later paper, where he enters into greater detail, he puts the Sewerby gravels, which have yielded so many Pleistocene Mammalian remains, distinctly wnder the whole Glacial series, and notably under the so-called basement bed. He comes to precisely the same conclusion in regard to the marine shell bed at Speeton (op. cit. pp. 410-412). In the discussion on this paper Mr. E. T. Newton describes the remains of mammals from Sewerby as just such an assemblage as might be expected in an undoubted Pleistocene deposit. It seems to me, therefore, that the Yorkshire evidence, wherever we can test it, agrees with that of Scotland and of Cheshire in compelling the conclusion that the horizon containing remains of the Mammoth and its companions is distinctly below the Drift beds. (To be continued.) IV.—Tue Reported OccurRENCE OF AVMONITES JURENSIS IN THE NORTHAMPTON SANDS. By 8. S. Buckman, F.G.S. N the Gerotoetcan Magazine (Dec. III. Vol. VIII. No. 329, p- 493, Nov. 1891), Mr. E. T. Newton has a “Note on the Occurrence of Am. jurensis in the Ironstone of the Northampton Sands in the Neighbourhood of Northampton.” This note had especial interest for me, from my having contested Mr. Beeby Thompson’s view of the Jurensis-zone being represented by the clayey beds beneath the Sands; and, in fact, it seemed to support my argument. Further reading, however, obliged me to confess that I could not claim this support; for Mr. Newton says (p. 494), “that the specimens of Am. jurensis agree exactly with Dr. Wright’s plate 79 (Lias Ammonites).” Now, in 1887, I pointed out that this form of Wright’s was very different to Zieten’s jurensis, and that it occurred in the Opalinum- ‘zone ;' and, in 1888, having occasion to refer to it in some sections, I named the form afresh Lytoceras Wrighti.2 Further, the same form is figured by Branco, under the name Lytoceras dilucidum on the authority ‘ Dumortier (non Oppel).” * The form called Lytoceras Wrighti differs materially from Zieten’s 1 Inferior Oolite, etc., Proc. Cotteswold Club, vol. ix pt. 11. p. 134, footnote, 1887. 2 Monogr. Lias Amm. pt. ii. p. 44, footnote, Pal. Soc. 1888. 3 Untere Dogger, Abh. geol. spez. ‘karte Elsass- Lothringen, Bd. II. pl. i. fig. 8, ~ S. S. Buckman—On Ammonites Jurensis.. 259 original Am. jurensis in the amount of involution, the extent of compression, the very different-shaped umbilicus,’ and the broader whorls. Even if the term ‘species’ be interpreted in a very liberal sense, to include both forms.as jurensis, the differences remain the same. Wright’s fossil is not the typical jurensis ; and, moreover, it is -a form characteristic of the Opalinum-zone. Whether it be regarded as a different species, or only a mutation of jurensis, it is advantageous to mark its differences by a name—Lytoceras Wrighti. The evidence of the Jurensis-zone in the Northampton Sands is thus narrowed down to Am. insignis. The typical form is highly characteristic of the Jurensis-zone; but there are several mutations and allied species which are characteristic of the Opalinum-zone. For instance, the ‘“ Insignis var.,” which Newton says agrees with Wright’s pl. 75, figs. 1-3, is quite an aberrant form of Hammatoceras (Insignis-group). It differs especially from insignis in ornamentation, and in having ventral furrows. As itis not named, to my knowledge, I think it might appropriately be called Hammatoceras Newtout. It occurs in Dorset quite high up in the Opalinum-zone. Its nearest allied form is Am. Alleoni, Dumortier, of the same zone, which is less coarsely ornate, less sulcate, and more involute. So far the bulk of Mr. Newton’s evidence seems to indicate the Northampton Sands being the Opalinum-zone, a conclusion I expressed in Monogr. Amm. p. 58, 1888. The occurrence of Am. Murchisone in the Opalinum-zone has been noted by myself and several other authors ; but the real head-quarters of Murchisone are on a distinctly higher level than the head-quarters of Opalinum. As regards the Jurensis-zone in Northamptonshire, my position is simply agnostic. I know no Ammonite-evidence,—barring, perhaps, Mr. Newton’s “ insignis ””—to show the existence of any of the four levels—Dumortieria-, Dispansum-, Striatulum-, Variabilis-beds—of this zone, which are easily recognized by an abundant Ammonite-fauna for about 80 miles from Haresfield to the Dorset coast; but the species of some or all may ultimately be found to occur in the Northampton Sand, and I doubt not in the same successional order. Of the Opalinum-zone there is good evidence for the existence of the upper level Opalinum-beds; of the lower level, Moorei-beds, Lytoceras Wrighti appears to be the only evidence. This is not sufficient—see sections Monogr. Amm. p. 45, et seq. A summary of the species allied to or similar to 4. jurensis may be useful in this connexion. As their genealogy, synonymy, etc., will be given more fully in a future paper, only the briefest notice will be made. 1. Am. jurensis, Zieten. Oval whorls, very little involute. Very rare. Burton Bradstock, Yeovil Sands. 2. Am. perlevis, Denckmann (usually called jurensis). It differs only in being more compressed ventrally, and having a more pro- nounced inner margin. Scarce. Dispansum-beds, Cotteswolds. 3. Am. phyllicinctus, Quenstedt. Like the last, but more evolute. } The umbilicus of the typical righti is basin-shaped, that of the typical jwrensis wider and graduated. 260 G. W. Bulman—Revised Theory of Glaciation. Only a fragment. Bottom Yeovil Sands (Dispanswm-beds), Bradford Abbas. 4. Lytoceras sigaloen,’ n. sp. S. Buckman (Ammonites jurensis, d’Orbigny (non Zieten), Pal. frang. pl. 100). It has been thought that this is the species Oppel intended to call Amm. dilucidus ; but Oppel’s reference is to Quenstedt’s Amm. fimbriatus opalinus, which is that author’s name for cornucopie, d’Orbigny (non Young). Further, Oppel says, “that Amm. cornucopie and Eudesianus are the nearest allies to dilucidus.” It is reasonable to suppose that had he meant to call d’Orbigny’s jurensis by the name dilucidus, he would have said “that Zieten’s jurensis was the form nearest to dilucidus.” Lyt. sigaloen is like perlevis, but more compressed and more inyolute. A magnificent specimen, 16 inches (406 mm.) in diameter, is in my collection from Yeovil Sands, Haselbury, Somerset. 5. Lytoceras Wrighti, 8. Buckman. Monogr. page 44, footnote, 2, Pal. Soc. 1888. (Lyt. jurense, Wright (non Zieten), Lias Amm. pl. 79.) Like sigaloen, but very involute. Basin-shaped umbilicus. Opalinum-zone, Dorset, Somerset, Gloucestershire, etc. The above species, so far as their suture-lines and inner whorls are known, show clearly enough genetic relationship with Amm. Germanii, VOrb., torulosus, Zeit., and hircinus (Schloth.), Quenstedt. They lack entirely the extraordinary lengthy lobes—especially the superior lateral—of the Fimbriatus-group. 6. Ammonites linulatus, Quenstedt (Am. Schwab. pl. 48, fig. 2), is another form which may belong to the same group. It differs from jurensis in having a fan-shaped aperture with a high inner margin, Whorls depressed. Foreign only. Jurense-zone. Three other species have resemblance, but are not exactly allied to jurensis. 7. Am. amplus, Oppel. A quick-coiled, very inflated form. Not known in this country. Relationship uncertain. Murchisone-zone. 8. Lytoceras confusum, S. Buckman (jurensis auctorum). A slowly-coiled form with triangular aperture, and marked shoulder. Concavum-zone, Dorset. The inner whorls and young specimens sometimes show periodic ribs indicating relationship with ophioneum, Benecke, and rasile, Vacek. 9. Amm. trapeza, Quenstedt. A slowly-coiled, very evolute form, with subtriangular whorls, and more rounded-off shoulder. Very rare. Sherborne-zone with Amm. fissilobatus (Sowerbyi-zone of German authors). V.—Tue Revisep Asrronomican, THEORY oF GLACIATION, By G. W. Butman, M.A., B.Sc. ; Corbridge-on-Tyne. N “The Cause of an Ice Age” Sir R. Ball claims to have removed from the Astronomical Theory of Glaciation the greatest stumbling block in the way of its general acceptance, and to have placed it on a firm and unassailable foundation. And this stumbling block he considers to have been Sir J. Herschel’s 1 giyadces, smooth. G. W. Bulman—Revised Theory of Glaciation. 261 erroneous statement, that, of the total heat received by a hemisphere in a year, one-half is received during the summer, and the other half during winter. Sir R. Ball has worked out the true distribution of the yearly heat between the seasons, and arrived at figures about which he claims there can be no question. His result is, that of the total yearly heat received by a hemisphere, 37 per cent. is received during winter, and the remaining 63 per cent. during summer. Granting these figures, it is maintained that glaciation follows as a necessary consequence, whenever the difference in the lengths of summer and winter is sufficiently great. This difference in length between the two seasons formed the starting point of Dr. Croll’s Theory. It was supposed by him that the winter supply of heat being spread over a greater number of days, the temperature would be so reduced, and the snowfall so increased thereby, that finally—with the aid of ocean currents, ete. —glaciation would result. And in showing that only 37, instead of 50, per cent. of the yearly heat is received during winter, Sir R. Ball appears to have removed a difficulty ; 37 per cent. of the yearly heat would certainly not maintain so high a temperature as 50 per cent. during the lengthened glacial winter. But a little consideration will show that the removal of the difficulty is only apparent. Our present average winter temperature forms the starting point for the calculation of what it would be when the winter was at its longest, and this calculation can be made quite independently of the figures 37 and 50. The result will be the same whether we assume 37 or 50 per cent. of the yearly heat to be received during winter, for these figures do not necessarily enter into the calculation at all. They did not, as far as I am aware, enter into that of Dr. Croll, who reasoned correctly, that our present winter supply of heat, when spread over 199 days instead of 179, would produce an average temperature lower in proportion to the lengthening of the season. The difficulty in connexion with the supposition of balf the yearly heat supply coming in winter is rather that of understanding how a winter climate could be produced at all; for our winter being shorter, if it received the same amount of heat, would be actually hotter than summer. But granted that 50 per cent. of the annual heat supply permits a winter climate during a portion of the year at present, the lengthening of the season might be supposed to reduce the temperature as easily as on the supposition that the percentage was 387 per cent. Sir R. Ball considers that Dr. Croll was unacquainted with the unequal distribution of heat between the seasons, but he has not shown that any of the latter’s reasonings or calculations depend on the assumption of its equal distribution. The theory set forth in “The Cause of an Ice Age” is regarded as a revised form of Dr. Croll’s, but the two theories differ in certain essential particulars. For, in the first place, while the Revised 262 G. W. Bulman—Rrvised Theory of Glaciation. Theory attributes glaciation solely to the lengthening of one season at the expense of the other—in other words to purely astronomical causes, viz. eccentricity and the precession of the equinoxes—Dr. Croll attributed it to physical agencies brought into operation by these astronomical causes. Among these physical agencies by far the most important is the Gulf Stream. But according to the Revised Theory the deflection of this great ocean current is not required to produce glaciation, and Sir R. Ball supposes it to have flowed much as it does now during the Glacial period. And there are two considerations which seem to show that the Gulf Stream did modify our glacial climate, and which were, therefore, difficulties on Dr. Croll’s view. The first of these is, that paleeontological evidence seems to show, that the western shores of our island were warmer than the eastern—as they are to-day. And the second is, that in North America glaciation extended fully 10° further south’ than it did here. Again, while, according to Dr. Croll, the astronomical conditions might occur without leading to glaciation through secondary physical causes, the Revised Theory requires a group of glacial periods whenever the eccentricity is sufficiently great. Dr. Croll has indeed shown how the astronomical causes which under certain conditions —of distribution of land and water, etc.—would produce a group of glacial, separated by genial, periods, might, under other con- ditions, lead to a group of genial periods separated by others a little less genial. And thus—especially in his later writings—he seems to have allowed considerable force to Sir Chas. Lyell’s views on the cause of glaciation, though only as adjuncts to the Astronomical Theory. It is probably in the judicious combination of the two theories that the true solution of the glacial problem will have to be sought. While, then, the essence of Dr. Croll’s Theory consisted in the continued increase in the cold, due initially to a lengthened winter, by physical agencies thereby brought into action, the Revised Theory attributes glaciation entirely to the reduction in temperature produced by spreading the winter heat supply over a greater number of days. The question, then, of how far our present winter temperature would be reduced if its heat supply were spread over 199 days— the longest possible winter—is the critical point in the Revised Theory. If it can be shown that the consequent reduction of its winter temperature would place our climate on a level with those of countries now glaciated ; and that the summer supply of heat—as great as at present though concentrated into fewer days—would be unable to melt the ice and snow, then glaciation follows as a necessary result of the lengthening of the winter. But this has not yet been done. Sir R. Ball (Appendix pp. 177, 178) gives data from which the reduction in our average winter temperature during the winter of 199 days can be found. At present he calculates we receive a mean daily average of 0-75 — G. W. Bulman—Revised Theory of Glaciation. 263° of a heat unit during winter, and when that season is as its longest 0:68, which gives a difference of 0:07. Now each tenth of a unit comespeuds to a rise or fall of 30°, and hence 0-07 corresponds to as of 30° or 21°. Our present average winter temperature may be taken as 42°, and hence during the long winter it would be 21°. This would give us a climate milder than that of Greenland between the 10° and 0° January isotherms, since its mean winter temperature is probably not more than 6° above this. The climate represented by this winter average of 21° may perhaps be fairly compared to that of America between the 20° and 10° January isotherms which include the southern part of the region of the Great Lakes. That such a reduction in temperature would produce glaciation is not then apparent. Using a different method of calculation, however, I have arrived at a much lower temperature for the winter of 199 days. Assuming, as Sir R. Ball has done, that the direct heat of the sun is expended in keeping the earth above —300°, and taking our mean January temperature of 36-9° for convenience of comparison with the January isotherms, we have the following calculation : 036'9°, the temperature maintained by the direct heat of the sun at present, X +33= 308°, the same when that heat is spread over 199 instead of 179 days. This gives a mean Jauuary temperature of 3°, or a mean winter temperature of 9°, if we suppose this latter 6° in excess as at present. This would probably give us the winter climate of some part of that strip of Greenland before alluded to, and lying between the S.E. coast and a line drawn from about Ciavering Islands on the east to the point where the Arctic circle cuts the west Coast. This would indicate a climate like that of the above glaciated region ; but is it a necessary consequence that such a winter would produce perpetual snow in our latitude ? We must remember that the heat received during summer would be the same-in quantity as at present, though concentrated into fewer days; and the question to be decided is, would this heat be sufficient to melt the snow of the previous winter or not? It is not quite obvious that it would be, and the point seems one for careful consideration and calculation. What, for example, would be the effect on the ice of Greenland if we could transfer our summer there for a few years without altering its winter? One is inclined to suggest that a gradual clearing of the country from perpetual snow and ice would take place. And a comparison of the part of Greenland under consider- ation with the neighbourhood of Lake Superior and Quebee which lies between the same January isotherms is instructive. For while the former is glaciated, the latter is not; nor are those portions of Asia south of 60° N. lat., lying between the same isotherms. And the reason of this is doubtless their much hotter summers. Hence, although our summer heat supply may be less than that of the above 264 G. W. Bulman—Revised Theory of Glaciation. regions, it is still sufficiently greater than that of Greenland to make it difficult to believe that a mean winter temperature of 9° would reduce our country to the present state of the latter. We may, then, conclude that a mean winter temperature of 21°, or even of 9°, does not necessarily imply glacial conditions like those of Greenland at present. From Sir R. Ball’s data again, the average summer temperature during the most genial period possible, viz. when the summer is 199 days and the winter 166, can be calculated. The present mean daily heat of summer is 1:24, and during the summer of 199 days it would be 1:16. This gives a reduction of 0:08 of a heat unit, and since each tenth of a unit corresponds to a fall of 380°, we have io X 80°=24° as the difference in average temperature between our summer and that of the most genial period. If we take the July isotherms as rough guides to the average summer temperature, this would give us a Greenland summer during the most genial period. Such a summer climate can scarcely be supposed to have tempted the plants and animals of the tropics or subtropical regions to wander north to our latitudes. If, then, the burden of accounting for tropical, or subtropical, as well as glacial periods is to be laid on the Astronomical Theory of Glaciation, the revised form must be declared wanting. But these reductions of winter and summer temperatures depend largely on the number —300, which has been used in the calculations, and its use requires some justification. If the whole yearly heat supply of a hemisphere had been reduced, and not merely the daily average of winter; or if the earth in the absence of the sun could very rapidly cool down to —300°; then the above calculations might be taken as approximately true. But the yearly heat supply is not appreciably altered. Moreover, the earth—or particular hemisphere under consideration—has a certain temperature due to the heat of the previous summer ; and this temperature must share with the winter heat supply the task of maintaining the hemisphere above —3800°. Suppose this temperature resulting from the heat of the previous summer to be 55°. If, in the absence of the sun, the earth could sink from this to —300° in a few days, then this factor might be neglected. But supposing that instead of the above rapid rate of cooling it required, say, six months to cool down to —100°; then, instead of —300, we should have to use —100 in our calculations, and this would make important differences in our reasonings. I am not prepared to assert that —100 is the correct number, but it seems almost certain that —300 is too low, and that the earth would not sink to so low a temperature in six months. For the rate of cooling of a heated body diminishes rather rapidly with the diminution of its excess of temperature. Thus the rate of cooling for an excess of 80° C. is little more than a tenth of what it is for 240°C. Again, it has been shown that the rate of cooling diminishes with the density of the surrounding air up to a pressure of yooslooo0 Of an atmosphere. But the earth’s heat before it can radiate into stellar space must G. W. Bulman—Revised Theory of Glaciation. 265 pass through the exceedingly attenuated upper strata of the at- mosphere. Again, if cooling down to —3800° within six months were possible, we should expect to find some approach to this in the lowest recorded temperatures of the Arctic regions during the absence of the sun. It is true that in these regions the temperature is modified by warm winds and waters. Yet on still, clear nights, in places removed from the influence of ocean currents, these modi- fying causes will be reduced to a minimum. I have not myself come across any record of temperature so low as —80°, and even if we suppose it sometimes sinks lower, we have still no indication that —100° is too high for our calculation. And we have to remember, as a set off against the influence of winds and currents, and probable lower temperatures than any yet recorded, that the intense cold of the Arctic regions may be due to other causes besides radiation. The evaporation which takes place from the surface of ice and snow itself reduces the temperature already, it may be, far below freezing. Snow, again, falling on the open sea melis even in water already below freezing, and thereby adds to the cold. And there is another consideration which seems to show that —100° or even higher is a more suitable point to reckon from than —300°. According to Sir R. Ball the present difference in the mean daily average of heat between summer and winter is 1:24—0-°75, or 0-49. If +> of a unit means 30° difference in temperature, then ‘49 would be equivalent to 80°x4:9=147° And our present July temperature is 60°! The average difference between summer and winter is about 20°. This would seem to indicate that —50° is the most correct starting-point. Taking —200° or —100° as starting-points, then, according to Sir R. Ball’s calculation, the tenth of a heat unit will mean 20° or 10° instead of 30°, and the reduction in the average winter tempera- ture would be 33,x20°=14°, or 35x10°=7°. This would give 28°3°, or 35°3°, as the average winter temperature during the winter of 199 days. With these figures, then, the Revised Astronomical Theory seems insufficient to account for glaciation. On the other hand, they permit to a warmer summer during a genial period. It appears, then, that a suitable temperature as a basis for calcula- tion is the imperative need of the Theory, and that the use of —800° has not been justified. In his statements concerning the effects of varying eccentricity and the precession of the equinoxes on the length of the seasons, Sir R. Ball is not quite so clear as might be desired on a point of such primary importance to his Theory. Thus, on p. 95, we find the statement that, “with the present eccentricity of the earth’s orbit, the great possible difference between summer and winter would amount to 33 days. I do not mean that the actual disparity between summer and winter at the present moment is so much as this; it only, in fact, amounts to seven days, because at present the line of equinoxes does not happen to be adjusted in the manner described.” 266 G. W. Bulman—Revised Theory of Glaciation. But on page 97 we read: “When all circumstances combine to accentuate as much as possible the difference in the lengths of the seasons, one of them may be 199 days long and the other 166.” Again, on page 153, we find the statement that seven days is the greatest possible difference between the seasons under present eccentricity: ‘So long as the eccentricity of the earth's orbit remains at its present value, the difference between the lengths of the seasons will fluctuate between the extreme values of a winter seven days longer than a summer, and a summer seven days longer than a winter.” Yet, as we have seen, it is expressly stated, on page 95, that the present position of the line of equinoxes is noé such as to produce the maximum difference possible for the present eccentricity. And on page 167 it is stated that the present seasonal difference is “near its maximum for the present eccentricity of the orbit.” The true law is stated on page 152 thus: “The differences between the lengths of the seasons is, as a mathematician would say, a function of two other independent quantities; it partly depends upon the eccentricity of the earth’s orbit, and partly on the longitude of the perihelion, that is to say, on the position of the line of equinoxes with respect to the longer axis of the earth’s orbit; if there were no eccentricity, there could be no difference in the lengths of the seasons, no matter where the line of equinoxes may le. On the other hand, no matter what the eccentricity may be, there would be no difference in the lengths of the seasons if the line of equinoxes passed through perihelion.” That is to say, for each value of the eccentricity the difference in the length of the seasons may vary from zero to a certain maximum value determined by the eccentricity. This maximum difference, Sir R. Ball states, is found by multiplying the eccentricity by 465. Taking -0167922, the figures given by Sir J. Herschel as the present eccentricity, we obtain 7:8 days as the maximum difference. This maximum will occur when the line of the equinoxes is perpendicular to the major axis of the ellipse of the earth’s orbit; and the seasons will be equal when it coincides with the major axis. And by what is called precession of the equinoxes this line describes complete circles round the sun as centre, and thus takes up successively every possible position in relation to the major and minor axes of the earth’s orbit. With the greatest possible eccentricity the difference between the seasons may attain to 0:0745 x 465, that is, 83 days. In the above quotations the italics are mine. A slip appears to occur on p. 81 in reference to Fig. 2, p. 82. Instead of “the part AB is comparatively near the sun, while the other part XY, is as far as possible from the sun,” should we not read, ‘‘ the part AB is as near the sun as possible, while the other, XY, is comparatively far from the sun” ? And on p. 82, when we read, ‘it therefore sweeps across from X and [to?] Y in much less time than it takes to pass from A to B,” the reverse is doubtless intended. Sir R. Ball has brought forward certain facts in botanical distri- G. W. Bulman—Revised Theory of Glaciation. 267 bution as witnesses of the truth of the Revised Astronomical Theory. The facts, however, seem to me rather to testify against it. The argument is briefly thus: It has long been known that certain temperate forms of plants in regions far removed from each other and on opposite sides of the equator, exhibit a remarkable similarity. So great is the likeness that it is supposed that those in the south must have migrated from the north, or vice versa. They must, then, have crossed the equator, and that they did so is a proof that equatorial regions were at one time cooled down sufficiently to permit of the existence in them of these temperate forms of vegetation. And the Astronomical Theory requires that equatorial regions in the glaciated hemisphere should be thus cooled down. Thus the botanical facts seems to confirm the Astronomical Theory. But, although the lengthening of one season will reduce its average temperature, that of the other will be increased by the corresponding shortening. And if the present heat of the tropics during summer in our northern hemisphere would be fatal to temperate plants, much more would it be so during glaciation when the summer supply of heat was concentrated into 166 days. A calculation of what the temperature of the glacial summer would be from Sir R. Ball’s figures will perhaps make this more obvious. The mean daily heat during the glacial summer is given as 1°38, and at present as 1:24, which gives a difference of -14. Now if -1 of a heat unit corre- sponds to 30°, 14 will correspond to 42.° Taking the present average temperature of our equatorial regions as 80°, this gives 122° as that of the glacial summer ! The botanical facts, then, seem to testify that if a glacial period helped the plants over the equator, glaciation was not brought about according to the Revised Astronomical Theory. In seeking in the stratified rocks for evidence of the numerous glacial periods which must, according to the Astronomical Theory, have occurred in the past, Sir R. Ball’s method of interpreting the record has at least the merit of novelty. Dr. Croll, and other geologists, when in search of such evidence have weighted them- selves with the necessity of finding scratched and polished boulders, erratics, and other deposits analogous to those formed during the latest ice age. Sir R. Ball has rid himself of this impediment, and finds in the ordinary alternation of stratified beds a record cf alter- nate mild and glacial epochs. The scarcity of evidence of former Ice Ages, sufficient to satisfy the average geologist, is well known, and has hitherto formed one of the most—if not the most—serious stumbling blocks in the way of the Astronomical Theory of Glaciation. And the Revised Theory suffers more in this respect than did that of Dr. Croll. For accord- ing to the former glaciation follows as a necessary consequence, whenever the requisite astronomical conditions occur, viz. whenever by combination of high eccentricity and the approach of the line of equinoxes to a position perpendicular to the major axis of the earth’s orbit, the difference in length between the two seasons becomes 268 Reviews—C. L. Griesbach’s Central Himalayas. sufficiently accentuated. Dr. Croll, on the other hand, has shown, as we have seen, that, according to his views, the astronomical con- ditions may occur without leading to glaciation. Hence, according to the Revised Theory, a larger number of glacial periods in the past is necessary, and hence a larger amount of evidence of such should be expected from the geological record. The imperfection of the record doubtless accounts for much, yet it is difficult to believe that glacial periods could have occurred in the past with the frequency demanded by the Revised Astronomical Theory without leaving much more evidence of their occurrence than has yet been forthcoming. In conclusion, I have not wished in the foregoing remarks to show that the Astronomical Theory is insufficient to account for glaciation. I have rather endeavoured to call attention to certain calculations which will have to be made, and certain facts which will have to be established before the Revised form can be generally received as a satisfactory explanation. Thus it will have to be shown, by careful calculation and comparison with existing climates, that the reduction of the average winter temperature by the lengthening of that season would be sufficient to produce in our latitudes a snowfall comparable to that of Greenland at the present day. And granting such a snowfall, it will have to be shown that all the heat of the succeeding summer—the same in amount as now— would be insufficient to melt it. And in order to calculate the reduction in temperature, due to the lengthening of the winter, a suitable datum line of temperature will have to be fixed upon, after a careful consideration of the numerous factors involved. The supposed confirmation of the Astronomical Theory in the present distribution of temperate plants north and south of the equator, I have endeavoured to show is rather a contradiction, since the burning heat of the equatorial summer during glaciation would render the passage of such plants across the equator even more unlikely than it is to-day. I have demurred again to the suggestion that Sir R. Ball’s dis- covery removes any difficulty from the older Theory of Dr. Croll, and have drawn special attention to the essential differences between the two views. I have pointed out that the newer view more urgently demands evidence of former glacial periods in the geological record, and noted the easy way in which Sir R. Ball proposes to meet this demand. REVIEWS. I].—Geronocy or THE CenTraL Himazayas. By C. L. GriesBacsa, C.I.E., Superintendent, Geological Survey of India. Memoirs of the Geological Survey of India, Vol. XXIII. 1891, pp. 282, Pls. 27, Phototypes in the text 31, and 2 Maps. Y the term ‘Central Himalayas’ the author includes that portion of the system of mountain ranges fringing the southern margin of the the Tibetan Highlands, in which the head- waters of the Ganges drainage are situated, and which extend to o Reviews—C. L. Griesbach’s Central Himalayas. 269 the north-west as far as the Sutlej gorge. Within this area the Central Himalayas may be divided into a Northern range, in which is the water-shed of the region, and a Southern range which contains the highest peaks. This latter is mainly formed of crystalline rocks, chiefly gneisses and metamorphic schists, whilst the Northern range is almost entirely composed of a vast thickness of sedimentary strata ranging from the lowest Paleozoic to late Tertiary. This memoir mainly relates to the character of these sedimentary deposits, which are now elevated so as to form a high rim round the southern edge of the great high plateau of Hundés, which in its lowest portion is 12,000 to 16,000 feet above sea-level. The principal geological features of this region have already been made known in the works of General Strachey and Dr. F. Stoliczka; the present report, which is the result of nearly twelve years’ investigation, very materially adds to our knowledge of its geological structure, and in some respects considerably modifies the descriptions of the earlier writers. The region under consideration is indeed a wild one; a large part of it is above the line of perpetual snow, which in the Southern range is between 15,000 and 16,000 feet above the sea, and in the Northern somewhat higher. Nearly every valley above these elevations has its glacier, and some of these range from five to sixteen miles in length. A fact, interesting to glacial geologists. is noted by the author, viz. that during years of observation he failed to find striated and polished boulders in the moraines of these glaciers, whilst the bounding rock-walls of the glacier-valleys do not show the smooth and rounded surfaces, usually seen in other regions, and it is supposed that subaerial denudation and rapid weathering has obliterated the ice-markings. From the presence of morainic material at lower levels, the author concludes that the glaciers must formerly have extended much further than at present. In one respect the geologist has an advantage in these high mountain regions, for the rocks are not hidden by vegetation, and in the absence of snow the main stratigraphical features can be noted readily even from a distance. The main mass of the Himalayas consists. of an enormous thick- ness of crystalline rocks, in which two systems can be recognized ; an older of granitic gneiss, which is now known to be metamorphic granite; and a younger series of micaceous schists, talcose rocks, phyllites and gneiss, to which the name of “ Vaikrita” system is applied. Both the lower gneiss and Vaikrita systems are inter- penetrated by veins and masses of eruptive granite, which also traverse the next overlying Haimanta rocks. The lowest distinctly sedimentary rocks, which rest, without any clear line of division, on the Vaikrita schists and gneiss, consist at their base of thick beds of conglomerate and purple quartzites, suc- ceeded by shales and phyllites, and limited above by a zone of bright red quartz shales, with an estimated thickness altogether of 4000 feet. This series, named the ‘‘ Haimanta” system, is probably the equivalent of the Cambrian and older divisions, and may correspond with Strachey’s azoic slates. The only organisms yet found in them are traces of Crinoid-stems, casts of bivalves and of Bellerophon. 270 Reviews—C, L. Griesbach’s Central Himalayas. Conformably succeeding the Haimanta rocks in the sections between the parallel ranges of the Central Himalayas, is a series of shaly quartzites alternating with coral limestones about 300 feet in thickness, which, on the evidence of the fossils, are referred to the Lower Silurian, and resting on these are quartzite beds about 1000 feet thick, which are placed as Upper Silurian, although the fossils in them have not yet been fully determined. Next in ascending order are dark limestones, about 650 feet in thickness, containing Corals, Crinoids and Brachiopods, which are donbtfully placed as Devonian ; following these are red crinoidal limestones considered to be Lower Carboniferous and white quart- zites and dark limestones with Productus, belonging to the Upper Carboniferous. In Spiti, limestones containing Athyris royssii, Pro- ductus, etc., probably represent the highest beds of the Carboniferous in this region. According to Mr. Griesbach’s experience, there is a gradual passage between the different Paleozoic formations in the Hima- layas, and from the phyllites and quartz shales of the Haimantas or Cambrian, to the Upper Carboniferous, there is a perfect and con- tinuous sequence without the slightest unconformity. There are evidences of considerable physical changes at or near the close of the Carboniferous period, and the strata of this age are in places unconformably overlapped by shales with Productus, considered to be Permian. The interruption between the Carboniferous and Permian is followed by another long interval without a break, which continued until after the deposition of the Liassic limestones. The Permian Productus shales, not over 250 feet in thickness, are followed by the lowest beds of the Triassic series containing Otoceras. This series in the Northern range of the Himalayas consists mainly of limestones, dolomites and shales, in all about 4000 feet in thick- ness. ‘The resemblance between the Triassic rocks of this region and the Alpine facies of the same formation, long since recognized by Salter, Strachey and Suess, is confirmed by Griesbach, who divides this series into Lower, Middle, and Upper, corresponding respectively to the Bunter, Muschelkalk, and Keuper of Germany. The Rhetic series of the Himalayas consists also of limestones and dolomites, and resting on them are shelly limestones of Liassic age, having a thickness altogether of 2000 to 2500 feet. As in the Triassic, there is also in these Rhetic and Liassic rocks a very strong resemblance to the corresponding formations in the Alps, not only as regards the fossils, but in lithological character as well. There seems to be an unconformity or interruption between the Lias limestones and the next succeeding Spiti shales, which contain Ammonites and other fossils of Middle and Upper Jurassic type. Resting on the Jurassic Spiti shales there are sandstones and shales with Belemnites probably of Cretaceous age. Above these are light-grey limestones with Upper Cretaceous marine fossils, which are exposed in sections north of the Niti Pass, and in other passes across the watershed between the Ganges and the Sutlej at elevations between 16,000 and 18,000 feet above the sea. Reviews— Yorkshire Geological Society. Day Apparently conformable to the Upper Cretaceous strata, there is on the Hundés high plateau a marine Nummulitic formation much disturbed and altered by igneous rocks, and above this, but uncon- formably, are sandstones resembling the Siwaliks in character, but without fossils. The sandstones are covered by the horizontally ‘stratified beds of Newer Tertiary age, which form the plain of Handeés, extending 120 miles in length by 15 to 60 miles in breadth, at an elevation of about 15,000 feet above the sea. The sections in the ravines of the Sutlej, nearly 3000 feet deep, show that this plain is composed of boulders, gravel, clay, and mud of all degrees of fineness. ‘The only fossils known from these beds are Mammalian bones, which were at first considered to be of Siwalik age, but Luydekker has shown that they belonged to living genera, and that consequently the deposits are of late Pliocene or even Pleistocene age. Griesbach considers the beds to be of lacustrine origin. The lines of flexures which form the Himalayas are considered by the author to have existed in Paleozoic times; but the great lateral compressions which pushed up the enormous masses of the Central Asian plateau with its fringing rims of mountains were evidently formed after the deposition of the Miocene beds, since these latter are contorted and crushed, whilst they are covered by the nearly horizontal newer Tertiary deposits, just referred to, which are almost unaltered ; consequently the crushing must have taken place between the deposition of the Miocene and Pliocene formations. In Part II. the author gives a description of some of the principal sections, including those of Painkanda (Garhwal) and the Bhét Mahals of Kumaun, with notes on the Central Himalayas between the Kamet Peak and Spiti. A special feature in this Memoir is the number of excellent figures of natural profiles and ideal sections, the latter constructed on the scale of one mile to an inch both tor the vertical and horizontal dimensions. To these are added numerous heliographic reproductions of photographs, taken by the author, which afford realistic pictures of the physical and geological features of the regions described, and they show very clearly the wonderful extent of folding and contortion which the rocks have undergone. It may be said that the value and interest of this report is as much due to the well-known artistic ability of the author as to his capacity as an able geological investigator. IJ.—ProcEEDINGs OF THE YORKSHIRE GEOLOGICAL AND POLYTECHNIC Socrery, Vol. XII. Part I. pages 1-130, with 4 Plates. S8vo. (Halifax, 1892.) : ieee comprises some very interesting and useful papers. I. T. Hick gives a résumé of the latest information about the growth and structure of the Calamite from the Coal-measures of Yorkshire. II. B. Holgate, by means of a very careful examination of 60 beds of the Coal-measures at Leeds (Patent Brickyard, No. 1; Patent Brickyard, No. 2; Boyle’s Brickyard; and Gould and Stevenson, Hunslet) finds reasons for indicating .the original conditions and 272 Reviews— Yorkshire Geological Society. mode of. origin of the several strata, defining their methods of deposition and their properties. These strata are successively arranged (from below upwards) in a long table (pages 16-21), with (1) their local names; (2) their original constituents, and their included animals and plants; (8) the mode of their formation as deposits; (4) the changes that have taken place in them since their deposition; (5) their present properties and uses; (6) their thick- nesses. Thus, taking a series of Mr. Holgate’s results in order, it is pointed out that there is indication of (1) a beach; then (2) of dry land of fine siliceous loam: (8) sinking land (with spores, fish- remains, and trees) ; (4) land still sinking, and the deposit becoming coarser, with the water almost motionless, away from the force of the stream; (5) centre of the stream, water flowing more quickly ; (6) direction of river still changing, water with quickening speed ; (7) ripple-marks at top, stream changing course and leaving ripple- marks dry; (8) stream again, over dried sandstone, depositing fine white sand, which takes casts of ripple-marks below ; (9) centre of stream now at some distance, and water moving gently; (10) water more rapid; (11) water very slow; mud with Anthracosiz, fish- scales and water-plants; (12) stream quickening, and so on, with ever variable conditions of muds, sands, and coals, with or without Fishes, Anthracosiz, Lepidostrobi, Stigmariz, Ferns, Calamites, ete. The salt and mineral waters are referred to; the seat-earths or fire-clays with their included roots and rootlets, are especially noticed (pp. 11-18), with their relation to the trees and plants once rooted in them, and to the coal-beds overlying them. The shales, including the blue, brown, and grey “ binds,” and the ironstone nodules, some of which yield the ‘best Yorkshire iron,” are also described, both in the Table and at pages 13 and 14. The evidences of the growth of land and its replacement by water, at this area, usually with river-currents, but once at least forming a lake, with mud full of fishes and molluscs, are interesting, and apparently very judiciously worked out. The chemical action in dissolving and redepositing mineral-salts, and forming concretions and definite nodules are noticed; as well as the effects of lateral thrusts and slidings. Lastly, the appreciations and uses of the several beds, and their measured thicknesses, render this memoir very valuable both to the practical people of Leeds and to geologists in general. Ill. C. E. De Rance continues his important researches, with the other members of the Underground Water Committee of the British Association, and here treats of the underground waters in Lincoln- shire, as proved by borings at Gainsborough, Worksop, Horncastle (tapping at Woodhall Salim Spring and as shown in the Appendix, pp. 85-51) by the supply from wells and borings in the several geological series of strata, there being about 15 water-bearing horizons, half of which are regarded as good for a public water- supply. IV. G. R. Vine supplies ‘* Notes on some new little-known Hocene Polyzoa,” pp: 52-61, mostly from Fareham in Hampshire. The Reviews—Yorkshire Geological Society. 273° stratum from which Mr. A. Bell obtained them is regarded by him as “a passage-bed between the London Clay and the Bracklesham series.” From the Kocene beds of England Mr. Vine here enumerates 8 species of the Cyclostomata; and 21 of the Cheilostomata; and he describes 3 of the former, and 4 of the latter group. V. A. S. Woodward, treating of the “ Hybodont and Cestaciont Sharks of the Cretaceous Period,” first refers to the characteristics of the Hybodus of the Lias and other Mesozoic formations, and proceeds to describe in detail some of the special characters well shown in remains of Hybodus basanus, collected from the Wealden beds of the Hasting coast by the late Mr. 8. H. Beckles, and now in the British Museum. One of the specimens is shown in pl. i. and another in pl. ii. fig. 1. A dorsal fin-spine of Synechodon (?) from the Gault, p- 66, is figured in pl. ii. fig. 2. Some characteristic teeth of Synechodus Illingworthi (formerly recognized as Acrodus or Hybodus) are described pp. 66, 67, and figured pl. ii. figs. 1-7. The author considers that Drepanephorus, and some Cretaceous teeth known as Strophodus and Acrodus belong to Cestracion or the Port Jackson Shark; and one of these, Acrodus rugosus, he here describes and figures, p. 67, pl. ii. fig. 8. VI. J. E. Bedford directs attention to “Evidences of Glacial Action near Leeds,” on the Ganiston beds of the Lower Carboniferous shales and grits quarried at Headingley, in the valley below Mean- wood. He notices moraine material of sandy clay, with irregular patches of sand, and containing great quantities of subangular blocks of grit-rock derived from the Ganiston beds. The shales below have also been much bent and crushed. The probable direction and range of the ice are discussed. VII. J. S. Tute describes a limestone conglomerate of Permian age at Markington, anda section of Permian beds near Wormald Green. VIII. G. R. Vine describes (pp. 74-92), and figures in plates iii. and iv. some peculiar Paleozoic Polyozoa, belonging to the genera :— 1. Vinella, Ulrich; 1 species and variety: 2. Ascodictyon, Nicholson and Etheridge, jun.; 7 species: 3. Rhopalonaria; 2 species. These appear to be Ctenostamatous Polyzoa and early representatives of the Stoloniferous Vesicularide, or possibly of the Eutoprocta. The late Mr. Busk noted that Mr. Vine was the first to indicate this alliance and Mr. Ulrich accepted it, and added the genus Vznella to the group. They belong to the Silurian, Devonian, and Carboniferous formations of Britain and America. They consist of creeping or attached stolon-like threads, with numerous vesicles (cells? or zocecia ?), and plate iv. illustrates WARBSTO\w OTTERHAM TROSCASTLE EPICENTRUM 7 'e treeneaibs 6 \ Ve VICTORIA INN EGLOSKERRY \, /. N 7 psu ER \ / a O TREWEN / CAMELFORD ALT/ARNON 57 FIVE LANES INN +} mi cHAELsTow 452 ERTON yea ees ee _-—— SCALE OF MILES o 1 pee 3 es Wier Sound-phenomena.—With three exceptions (Altarnon, N. Penlean, and Victoria Inn) earthquake-sounds are recorded at all the places of observation, and the omission at these places is probably acci- dental. The sounds were heard at all the places which determine the boundary of the disturbed area. They were also, I am informed, heard two miles to the east of Bolverton, so that it is possible that the sound-area may have slightly overlapped the disturbed area towards the south-east. Otherwise the two areas seem to have coincided approximately. The sound is said to have preceded the shock at Michaelstow, to have accompanied it at Bolverton, Boscastle, Camelford, Jacobstow, St. Clether, St. Juliot and Treneglos, and to have preceded, accom- panied and followed it at Poundstock. At Boscastle, Dr. Wade informs me that the sound resembled that of a ponderous waggon going over a vacuum. It was heard while the shocks lasted and during the whole of the interval of about ten 302 Chas. Davison—British Earthquakes, 1891. seconds between them; the intensity being nearly uniform through- out, but greatest when the vibrations were felt, and slightly less during the interval between them. Another observer at the same place compares the sound to that made by an unusually heavy waggon going over a bridge, but it was not heard by him during the whole of the interval between the shocks. ‘There was silence,” he remarks, ‘‘for a second or two between the rumbles; the latter went off as the sound of a heavy ground sea after breaking on the shore ; it was shorter and fainter than the first.” At every other place the sound ceased for a greater or less time between the shocks. At Michaelstow a loud rumbling sound, resembling the passing of a very heavy vehicle over a hard road, preceded each shock, growing rapidly in volume and dying quickly away. At St. Juliot, again, the sound accompanied each shock, varying only slightly in intensity, but greatest at the moments when the vibrations were felt. Origin of the Shocks.—The first point to be determined is the origin of the double shock, and of this three explanations may be given. (1) The seismic focus may have consisted of two detached portions, or have contained two regions of maximum initial intensity ; (2) there may have been a repetition of the originating impulse at one and the same spot; or (3) a repetition of the originating impulse at another and different spot ; the focus, or line, joining the foci, being in any case directed north and south. If the first explanation were the correct one, the interval between the two shocks would have been greatest in the continuation of the line joining the foci, 7.e. in the north and south parts of the dis- turbed area, and least in the east and west parts. Without placing too great a reliance on the estimates of this interval given above, it is clear that they offer little support to this theory. At Michaelstow, indeed, the second shock was said to follow ‘‘almost instantaneously” after the first, but the interval was yet long enough to allow the rumbling sound to cease and to be heard again before the second shock; and Michaelstow is not far from the southern boundary of the disturbed area. The second explanation is also out of the question, on account of the different relative intensity of the shocks at different places. There remains the third theory, and the evidence, such as it is, seems clearly in its favour. At all parts of the disturbed area there would be a perceptible interval between the shocks, provided the interval between the initial impulses was not equal to the time required for the earth-wave from a further and earlier focus to overtake that from a nearer and later one. The distance between the foci will, however, account to some extent for the variations in the estimates of the interval between the shocks. \ More important evidence is furnished by the different relative intensity of the two shocks at different places. We have seen that the first shock was the stronger at Boscastle, Poundstock, and St. Juliot, all lying to the north of the epicentrum ; the second decidedly the stronger at Michaelstow, near the southern end of the disturbed Chas. Davison—British Earthquakes, 1891. 303 area; while at St. Clether, which is near the eastern boundary, the intensities of the two shocks were approximately equal. I conclude, then, the shocks were really distinct, the focus of the second being to the south of that of the first ; and it is obvious that, if this were the case, the interval between the two shocks should have been least at the southern end of the disturbed area, an infer- ence which agrees with the estimate already quoted of the apparently short interval at Michaelstow. The position indicated on the map as that of the epicentrum probably corresponds closely with the superficial position of the centre of intensity of the whole seismic focus. The distance between the two foci may have been as much as two or three miles, but Dr. Wade’s interesting observation at Boscastle of the sound being heard during the whole interval between the shocks seems to show that the foci were not completely isolated. If the shocks were due to fault-slipping,! we may infer, from the form of the disturbed area and from the facts summarised in the preceding paragraphs, that the direction of the fault must. be north and south. Boscastle, again, is the only known place where the sound was heard continuously between the two shocks, and, as mentioned above, the sound-area may have overlapped the disturbed area along its south-east margin. These facts seem to indicate, but not with certainty, (1) that Bos- castle must be near the spot where the normal to the seismic focus meets the surface of the earth, and (2) that the upper margin of the focus from which the sound-vibrations proceeded lay to the east or south-east of the epicentrum; 7.e. that the fault must hade to the westward. Lastly, if this conclusion be correct, the line in which the fault intersects the surface must pass to the east of the epicentrum, and at a distance from it probably not much greater than one or two miles.” Summing up on the supposition that the earthquake was fault- formed: the first shock was probably caused by a slip within a small area about a mile north of the point marked as the epicentrum ; but the slip continued southward for about two miles, though so slight in extent that only earthquake-sounds were produced, an interval of perhaps five or more seconds being necessary for the slipping over this distance to take place; at the southern end the slip being again great enough within a small area to produve a shock of approximately the same intensity as the first. It is interesting to notice the relation between this earthquake ata that felt in East Cornwall on October 7, 1889. The boundary of the disturbed area of the latter is indicated on the map by a dotted line. Its epicentrum lay about 2? miles S.W. of Altarnon, and the 1 There is no fault marked in the Survey Map of the district with which the earthquake can be connected. * The fact that no shock was noticed at Otterham is in favour of the position above assigned to the fault; for, if the earthquake were due to fault-slipping, the earth-waves in the rock-masses on either side of the fault would start in opposite phases of vibration and might possibly interfere to a very great extent along the line of fault. (See a paper ‘“‘ ‘On the Existence of Undisturbed Spots in Earthquake- shaken Areas,” Grou, Mac, Dec. III. Vol. III. 1886, p. 157). 304 Chas. Davison—British Earthquakes, 1891. longer axis of the disturbed area ran east and west, .e. parallel to the direction of folding in the district. The earthquake of 1889 was therefore a longitudinal earthquake, and that of 1891 a transverse earthquake. Authorities.—The published accounts of this earthquake are very scanty, and for all that is of value in the preceding description I am indebted to the kindness of the following ladies and gentlemen who courteously replied to my inquiries either addressed to them or printed in two or three of the local newspapers: Bolverton, Rev. 8. G. Gregory; Boscastle, Dr. A. Wade and Mr. J. Brown; Camelford, Mr. E. Rogers; Egloskerry, Rev. W. S. Sloane-Evans; Five Lanes Inn, Mr. A. Chapman; Jacobstow, Rev. F. T. Batchelor; Michael- stow, Rev. W. H. Gillett; Otterham, Rev. EH. H. Archer-Shepherd ; Poundstock, Mr. J. D. Graf; St. Clether, Rev. F. Partridge; St. Juliot, Mr. W. H. Sanders; St. Kew, Mr. W. Hitchin; Tintagel, Miss B. F. Cooke; Treneglos, Mr. J. C. Chapman; Victoria Inn, Mrs. Greenwood ; Warbstow, Mr. W. Petherick. EARTHQUAKES IN INVERNESS-SHIRE. For the following list of shocks I am indebted to the valuable observations of Mr. John Grant of Invergarry; Mr. Murdoch Matheson, who has removed from Feddan to Ardochy; and Mr. A. Campbell, of Loch-hourn Head. Ardochy hes on the north side of Loch Garry about a mile from its west end. At Glen Quoich and Glen Kingie, earthquake-shocks are occasionally felt, though none has been observed at either place during the past year by Mr. D. Grant and Mr. A. G. Foster, both of whom are doing useful work in recording the occurrence of earthquakes felt by them. It is worthy of notice that all the six places here mentioned lie close to a line joining Invergarry and Lochhourn Head. Every one of the seven- teen or eighteen shocks mentioned below was felt by more than one observer. Feb. 24. 22h. 55m., Invergarry, resembling the sound of a carriage. sf 28h. 20m., Loch-hourn Head, a rumbling noise with a slight movement, lasting fully ten seconds. ‘This shock may be the same as the preceding, but the distance between Invergarry and Loch-hourn Head is 25 miles, and no shock is recorded about this time at either Ardochy, Glen Quoich or Glen Kingie. Feb. 25. 1h. 15m., Invergarry, like a heavy carriage passing. Mar. 1. 15h. 15m., Ardochy, a shock lasting eight seconds. i 21h. 25m., Ardochy, a stronger shock than the preceding, lasting four seconds, and preceded by a rumbling noise. Mar. 2. 22h. 15m., Invergarry, like a heavy carriage passing. Apr. 24. 14h. 80m., Ardochy, a shock of intensity 1V., followed by a noise resembling thunder. Aug. 27. 4h. 30m. and 6h., Invergarry, like a heavy carriage passing. Aug. 30. 16h. 15m., Invergarry, the same. Nov. 16. 10h. 25m., 14h. 15m., and 20h. 45m., Ardochy, slight shocks without any accompanying noise. G. W. Bulman—Formation of the Boulder-clay. 305 Dec. 6. 9h. 55m., Invergarry, like a heavy carriage passing. Dec. 26. 1h. 20m., Loch-hourn Head, a very slight noise and trembling of the floor on which the observer was standing. Dec. 28. 20h. 20m. and 21h. 24m., Invergarry, like a heavy carriage passing. Dec. 30. 9h. 45m., Invergarry, like a heavy train crossing a bridge. DovustruL HARTHQUAKE. The following shock is entered under this heading, having been noticed by only one observer; but, judging from the careful descrip- tion, I believe there can be little dowbt as to its seismic nature. October 25, 1891, about 16h., Bournemouth.—A notice of this shock by Mr. Henry Cecil appeared in Nature (vol. 44, p. 614), and this, together with a more detailed description which Mr. Cecil kindly sent me, is the source of the following account. A dull thud was heard, as of a heavy fall underground, and instantly afterwards (all but simultaneously with it) a single momentary shock without any preceding or following tremor. The observer’s eyes were directed at the time on a plant resting on the table beside him, and, when the shock occurred, the long, pendant, lightly-poised leaves of the plant were violently agitated, waving up and down through a large are for several seconds. The movement of the ground must have been vertical, and Mr. Cecil remarks that his impression was that it was first upward and then downward. It being Sunday afternoon, almost all traffic was suspended, but, shortly after°the shock, a heavy carriage passed along the adjoining road without producing any perceptible movement in the plant. Mr. Cecil informs me that he has felt several slight shocks at Bournemouth, and he believes that in the present case the sound and shock were of seismic origin. ITV.—Was THE BovuLDER-cLAY FORMED BENEATH THE IcE? By G. W. Burman, M.A., B.Sc. ; Corbridge-on-Tyne. EOLOGICAL opinion is still divided on the subject of the formation of the Boulder-clay. By some it is held to be the sole work of the ice, and accumulated beneath it; by others it is looked upon as a marine deposit, though deriving its materials from the grinding action of the ice-sheet or glacier. Some geologists, again, hold that the “Till”—as distinct from the Boulder-clay— was formed beneath the ice, but that the latter is a marine deposit laid down in glacial seas. Neither the first nor the third of these views can as yet be said to have received the stamp of geological certainty, for it has not been conclusively shown that any such deposit is being formed beneath the ice at the present day; nor can it be inferred from what we know of the properties of ice in the form of glacier or ice-sheet that such a deposit ought to be the result of its action. Thus no deposit analogous to Boulder-clay is found in Switzerland DECADE I1I.—VOL. IX.—NO. VII. 20 306 G. W. Bulman—Formation of the Boulder-clay. where the ice has retreated within recent times. With regard to this point Prof. Bonney writes as follows : “The Glaciers of the Swiss and Savoy Alps have been retreating for several years, hence, if anything like ground moraine existed, this would be a very favourable time for observing it. In no case have I been able to find signs of any deposit resembling Till or Boulder-clay ; the detrital matter which is scattered, generally sparsely, over the slope left bare by the retreating glacier has fallen from its surface, like ordinary terminal moraine. Further, by availing myself of crevasses, etc., I have made my way occasion- ally for some little distance beneath the ice. Nothing has been seen but bare rock, with now and then a film of mud or a passing stone. In short, the result of an experience of some years has convinced me, that if anything like the Till or Ground Moraine of recent glacialists exists in the Alps, it is a very local and exceptional phenomenon.” ? And so we find a tendency among those who believe the Boulder- clay was accumulated beneath the ice, to push back the question of its origin from the comparatively known regions of Alpine glaciers to the unknown sub-glacial area of Central Greenland, Thus Sir A. Geikie refers to what must be taking place beneath a vast continental ice-sheet : (1) “In such comparatively small and narrow ice-sheets as the present glaciers of Switzerland, the rock bottom on which the ice moves is usually, as far as can be examined, swept clean by the trickle or rush of water over it from the melting ice. But when the ice does not flow in a mere big drain (which after all, the largest Alpine valley really is), but overspreads a wide area of uneven ground, there cannot fail to be a great accumulation of rubbish here and there underneath it. The sheet of ice that once filled the broad central plain of Switzerland between the Alps and the Jura certainly pushed a vast deal of mud, sand, and stones over the floor of the valley. The material is known to Swiss geologists as the Moraine profonde or Grundmorane (=—Boulder-clay, Till, or bottom-moraine) ” (Text-Book of Geology, p. 411). (2) «We know as yet very little regarding its (the Grundmorane) formation in Greenland. Most of our knowledge regarding it is derived from a study of the Till or Boulder-clay in more southern latitudes, which is believed to represent the bottom moraine of an ancient ice-sheet (ibid. p. 417). The weakness of the argument is further illustrated by the following passage from the Physical Geology of Prof. Green, in which | have italicised certain parts : “We have already seen that under such a sheet [continental ice-sheet] there is probably formed an accumulation of clay and stones known as Moraine profonde or Grund-morine, and Till resembles exactly what we picture to ourselves that this deposit musé be like. There would be weight enough to give rise to the intense toughness and the close and irregular packing of the stones, and the ' Grou. Maa, Vol. XIII. p. 197. G. W. Bulman—Formation of the Boulder-clay. 307 scratching and polishing would be produced as the mass was moved hither and thither by the flow of the ice...... Though the existence of the Moraine profonde is to a certain eatent hypothetical, the probability, that such an accumulation is formed beneath large ice-sheets is so great, and its character, if it exists, must be so exactly that of Till, that nearly all geologists are now agreed to look upon the latter as having been formed by the grinding and wearing away by an ice-sheet of the ground on which it rested” (p. 264). But as far as evidence from Greenland is available it throws as little light on the origin of Boulder-clay as the Swiss valleys. Thus Nordenskiold describes an area lately left by the ice as containing no moraines, and in his description makes no mention of Boulder- clay: “We passed, in fact, over ground that had but lately been abandoned by the inland ice..... Everywhere occur rounded, but seldom scratched, hills of gneiss with erratic blocks in the most unstable positions of equilibrium, separated by valleys with small mountain-lakes and scratched rock surfaces. On the other hand, no real moraines were discoverable. These, indeed, seem to be commonly absent in Scandinavia; and are, generally speaking, more charac- teristic of small glaciers than of real Inland Ice” (Arctic Voyages, Macmillan, 1879, pp. 169, 170). And further, in describing the clay-beds of Greenland, Nordenskiéld speaks of them as formed outside the ice-sheet. “The material of the clay-beds has evidently been deposited by the glacier rivers whose muddy water everywhere burst out from under the inland ice, but in general the deposits are sea formations, a.e. they have been deposited under the level of the sea” (Guo. Mae. Vol. IX. p. 410). And no deposit resembling Boulder-clay is described by him as occurring on that strip of Western Greenland not covered by the ice-sheet at present. Similar remarks may be made with regard to those areas in America where a retreat of the ice permits an examination of the ground recently occupied by it. In the American Journal of Science, March, 1892, for example, is an interesting description of Mount St. Elias and its Glaciers. Where the ice has retreated glaciated surfaces are seen, but no Boulder-clay. Spread out, however, over the whole area between the ice and the sea is a mass of stony moranic matter. Streams from the glaciers carry the finely-ground rock matter into the sea. The probability or otherwise of the Boulder-clay having been formed beneath the ice may be further considered in the light of what we know of the physics of glacier action. To meet the requirements of the geologist, the ice, in the form of glacier or ice-sheet, must accomplish—and apparently does accomplish—a variety of seemingly incompatible actions. It must clear the ground of superficial accumulations and grind and polish tbe rock below, while at the same time it must glide over loose deposits of clay and Stones without disturbing them; it must round and polish certain 308 G. W. Bulman—Formation of the Boulder-clay. stones while carrying others for long distances without taking off their sharp edges ; it must hold firmly embedded in its lower surface stones with which to striate and groove the rocks below, while at the same time it leaves a large number behind to form the moraine profonde. And when we turn to the glaciers themselves we see them accom- plishing a series of actions as apparently incompatible. For while the ice flows along its bed more or less like a river, it yet polishes and striates the rocks below, apparently by holding stones firmly grasped in its lower part; and while grinding down the rocks over which it passes to the finest powder, it has yet been observed to rise gently over loose deposits of clay and stones without disturbing them ; at times it allows stones to sink into it, so that its surface moraines disappear, while at other times it works up the stones from below to the surface, and they appear again. While the anomalies of Glacial action are so great it would be rash to assert that Boulder-clay cannot be formed beneath the ice, but the great fact of constantly running sub-glacial streams renders it improbable. These streams laden with fine rock-flour issue from the termination of glacier and ice-sheet summer and winter. How far such streams ascend the glacial valleys it is difficult to say. Probably they extend at least as far as the point where the névé gives place to the ice-river. Such a conclusion, at least, seems to follow from certain considerations as to the probable temperature beneath a considerable sheet of ice or snow. Ice and snow are bad conductors of heat, and hence the lower surface of a thick ice-sheet will tend to take the temperature due to the surface of the earth—say, about 50° F. The pressure, moreover, of the superincumbent ice will tend to liquify the lower portion. Such streams running beneath the entire extent of the glacier proper would readily account for the number of rounded stones found in the Boulder-clay, as well as for intercalations of sand and gravel; but do not permit the supposition of a sufficient quantity of rock-flour being left behind to form more than such fragmentary fringes and patches as a river leaves along its course. The greater part of this finely ground rock matter will be carried beyond the limit of the ice, and if the glacial streams spread out over level plains deposits of clay of considerable extent might be formed on land. Most of this sediment, however, will be laid down in water. If we study the distribution of glacial mud in Switzerland at the present day we find it is mostly laid down in lakes. Many of its glacial mud-laden streams fall into lakes from which they emerge clear and pure, having deposited their sediment therein. Thus the Rhine flows into Lake Constance and the Unter Sea, the Rhone into the Lake of Geneva, the Aar into the Lakes of Brienz and of Thun, the Ticino into Lake Maggiore, the Reuss into the Lake of Lucerne. This fine sediment would provide the clay, and if boulders could at times be carried in, the conditions for the formation of boulder-clay would be present in these Swiss lakes to-day. And, whatever may G. W. Bulman—Formation of the Boulder-clay. 309 be the case now, when the ice extended further and reached the lakes, small bergs would be frequently detached, and melting, allow their burden of stones to sink to the bottom of the lake amid the clay there accumulating. Prof. Nordenskiold, again, has described how a similar deposit is being formed in Greenland at the present day. “At the foot of the glacier,’ he writes, ‘‘ we often find, as in fig. 2, ponds or lakes in which is deposited a fresh-water glacial-clay, containing angular blocks of stone, scattered around by small icebergs’ (Arctic Voyages, pp. 170, 171, Macmillan, 1879). But it is when we turn to the sea that we find the most promising method of accounting for the origin of Boulder-clay in general. For it seems obvious that deposits analogous to Boulder- clay must be accumulating on a large scale in the seas off the coasts of Greenland and other arctic lands. Sub-glacial rivers, laden with the finer products of glaciation, are discharging themselves into the sea throughout the year. Icebergs, also, are constantly being formed and floated away with their loads of debris. Part of this debris no doubt will be deposited only when the bergs melt in more southern latitudes ; but a part will also be laid down near the coast and among the finer sediment by the overturning of the bergs, which not unfrequently happens. And it is, perhaps, worthy of note that large quantities of glaciated stones may be carried by such bergs and deposited amid accumulations of clay taking place in latitudes far south of the limits of glaciation. A clay full of glaciated stones may thus noé necessarily imply the glaciation of the latitude where it occurs. The opinion that the Boulder-clay was thus formed in the sea has been expressed by eminent geologists. Thus Sir J. W. Dawson in his “Handbook of Geology for Canadian Students,” expresses his opinion thus: (1) “Under these circumstances moraines were formed on the land, and sheets of stony clay with boulders in the sea, forming what has been termed the Boulder-clay or “Till” (p. 114). (2) “That this Boulder-clay is a sub-marine and not a sub-aerial deposit, seems to be rendered probable by the circumstance, that many of the boulders of the native sandstone are so soft that they crumble immediately when exposed to the weather and frost” p. 154). And Prof. Boyd-Dawkins writes: “‘The hypothesis ..... that the Boulder-clays have been formed on land is open to the objection that no similar clays have been. proved to have been so formed, either in the Arctic regions, where the ice-sheet has retreated, or in the districts forsaken by the glaciers in the Alps or Pyrenees, or in any other mountain-chain. Similar deposits, however, have been met with in Davis Strait and in the North Atlantic, which have been formed by melting icebergs; and we may therefore conclude that the Boulder-clays have had a like origin” (‘‘ Harly Man in Britain,” pp. 116, 117). _ The chief difficulty in the way of this marine origin of the Boulder- 310 T. Mellard Reade— Glacial Geology. clay is perhaps the absence of lamination, so characteristic of deposits in water. But a consideration of the facts of the case suggests a possible explanation. The two general causes of original lamination —indeed I am not acquainted with any other—are the intermittent supply of sediment, and the presence of flat plates of mica. Both of these are probably absent in the case of the deposit in question. The ice provides a continuous supply of rock flour, and rivers laden with it flow from the glacier and ice-sheet all the year through ; and it permits the existence of no large flat plates of mica. The general conclusion, then, to be derived from a study of glacial action seems to be that while the greater part of the rock-flour which goes to form the clay is carried beyond the limits of the ice and laid down in lakes, the sea, or on land, fringes and patches of the same may be left behind in the valleys occupied by the glacier or ice-sheet. V.—GuLaciAL GEOLOGY: OLD ann NEw. By T. Mettarp Reape, C.E., F.G.S., F.R.I.B.A, Historical and Personal. VER twenty years ago I commenced the study of the glacial deposits of the neighbourhood of Liverpool, and as the observa- tions grew they came to embrace a considerable share of the drainage- basin of the Irish Sea. I have personally inspected and kept full records of all of the important artificial excavations likely to throw light upon the sub- ject, in addition to examining and making sections of the natural exposures of glacial drift which abound on the north-west coast of England, the coast of Wales, and in the river valleys draining into the Irish Sea, and to a lesser extent the drift on the east-coast of Ireland and the south of Scotland. These observations, together with others in districts outside the special area of my work, have been communicated to various Societies and Magazines.’ _This being my record, and glacial geology having during my time gone through several phases, it may perhaps interest some of the readers of the Gxrotocican Macazine if I give a resumé of the views I have been gradually led to adopt. 1 Proc. of Liverpool Geol. Soc. 1872-73, pp. 31, 32, pp. 42-65; 1873-74, pp- 50-72. Q.J.G.S8. vol. xxx. p. 27-41, 1874. Proc. of Liverpool Geol. Soc. vol. ii. pt. 1, pp. 19-27, 1875. Guror. Mae. Dec. II. Vol. III. p. 480, 1876. Proc. of Liverpool Geol. Soc. vol. iii. pt. 3, pp. 241-43, 1877. Grou. Mae. Dee. II. Vol. IV. pp. 38, 39, 1877. QJ.G.S. vol. xxxiv. pp. 808-810, 1878; vol. xxv. pp- 679-681, 1879. Proc. of Liverpool Geol. Soc. vol. iv. pt. 1, pp. 64-89, 1879 ; vol. iv. pt. 2, pp: 189-158, 1880; vol. iv. pt. 8, pp. 216-233, 1881. QJ.G.S. vol. XXxvill. pp. 222-238, 1882. Trans, Geol. Soc. Glasgow, vol. vi. pt. 2, pp. 264— 276,1882. Proc. of Liverpool Geol. Soc. vol. iv. pt. 5, pp. 864-3880, 1883. Q.J.G.S. vol. xxxix. pp. 83-132, 1883. ‘Trans. of Liverpool Geol. Asso. vol. ii. pp. 98-101, 1883. Q.J.G.S. vol. xl. pp. 267-269; vol. xl. pp. 270-272, 1884. Proc. of Liverpool Geol. Soc. vol. y. pt. 1, pp. 74-83, 1885. Q.J.G.S. vol, xli. pp. 102- 107; vol. xli. pp. 454-456, 1885. Proc. of Liverpool Geol. Soc. vol. v. pt. 4, pp- 377-879, 1888. Nature, vol. xl. p. 246, 1889. Proc. Liverpool Geol. Soc. vol. vi. pt. 2, p. 188, 1890; vol. vi. pt. 3, pp. 316-321, and pp. 333-4, 1891. Grou. Mae. Vol. VIII. Dec. 111. p. 291, 1891. Proc. Geol. Soc. 1892. T. Mellard Reade— Glacial Geology. dll On commencing the inquiry I had no idea whither my observa- tions would lead me, and had no prepossessions. I quickly found, however, that I came into collision with one of the prevailing views —J had almost said dogmas—of the day. The drift of the north-west of England had been arranged in a tripartite series consisting of, in ascending order, Lower Boulder Clay, Middle or Interglacial Sands and Gheamalls, and Upper Boulder- clay. My observations led me to believe that there were no suf- ficient grounds for such a geological division, and that the whole of the drift deposits were one glacial series from top to bottom. This view is now the one generally adopted, and also as I understand by the new school of glacialists who ascribe these deposits to the ploughing up of the Irish-Sea bottom by land ice. And this brings to my mind the fact that there has been a concurrent change of position on the part of the land-ice glacialists, for the old school believed in the occurrence of several interglacial periods and thought they could read the record of them in the deposits. Until lately the preponderance of opinion among geologists who have studied the subject in the field was that the glacial deposits of the north-west of England were sea-bottom in situ and that the high-level sands and gravels indicated a submergence of the land in glacial times to at least 1400 feet. The late Mr. Belt struck a new note when he boldly declared his belief that the high-level drift of Moel Tryfaen, in Carnarvonshire, had been pushed up into its present position by a sheet of land-ice traversing the Irish Sea.' Mr. Belt was listened to by few at the time, but in the whirligig of time he is now having ample revenge. The late Professor Carvill Lewis, fresh from his experiences in America, revived this idea of Belt’s in a modified form, and he also met with much opposition. Since his death the idea has fructified, and we now have an energetic band of geologists who are bent on nothing less than raising what was considered at first to be a “ wild idea” into a geological dogma. Whether there has been justification for this veering round of geological opinion it will be our object presently to inquire. In the meantime it is sufficient to suggest that it is not the province of geological enquiry to search out facts with the object consciously or unconsciously of running a theory, yet this is one of the many pitfalls against which Beorogica! reasoners have to be constantly on their guard. Tne GruactAL Drirt or THE IrR1IsH-Sea Basin AND ITs SYSTEM OF DISTRIBUTION. Low-Level Boulder-clay and Sands. The whole of the plains of Lancashire and Cheshire are, with the exception of local patches, covered with a mantle of Boulder- clay and sands of varying thickness, from a few feet in the more exposed localities to 160 feet in the deeper river channels. Both the clay and sands generally contain remains of mollusca in a more or less fragmentary condition. 1 Nature, vol. x. pp. 25, 26, 1874. 312 T. Mellard Reade—Glacial Geology. The Boulder-clay is usually of a brown colour, sometimes unctuous, and contains boulders and fragments of Northern rocks from the maximum of over 20 tons down to the finest gravel. The boulders are to the extent of fully 50 per cent. either planed or striated or both, and sometimes on several faces. They are often considerably rounded and the finer gravel to be obtained by washing the clay is extremely waterworn. The sand, if separated from its clayey matrix, is much rounded, some of the grains being extremely polished. The proportion of sand in the clay is much greater than would at first be thought, varying from 20 to 60 per cent. There is no geological difference between the Sands and the Boulder-clays, gradations from the one to the other can be met with though often they come together in sharp juxtaposition. If we trace these drift deposits up the valleys from the sea to the source of the rivers flowing in them, we find that the nature of the matrix of the drift lying in them is largely dependent upon the nature of the rocks the rivers traverse,’ that is to say, the sandy and gravelly drift increases when the rivers above them flow through sandstones and rocky ground as in the Dee above Chester, and the Mersey and Irwell in the neighbourhood of Manchester, while the rivers flowing over the New Red Marl have brought down an unctuous clay like that deposited by the Weaver in the Buried Valley of the Mersey at Widnes. Thus, while the contained stones have come from the northward, with the possible exception of some sandstones and gypsum of the New Red Marl, the matrix consisting of clay and sand has to the larger extent come down the river valleys. If we extend our observations further south into Shropshire we find a still greater development of sands. The drift by the Severn at Shrewsbury is nearly all red sand, the waterwashed débris of the New Red rocks. The erratics are still plentifully strewed about the county, and the well-known Eskdale granite and the grey granite of the south of Scotland, together with the andesitic rocks and voleanic ashes from the English Lake district are distinguishable. It is also a fact worth noting that on the plain of New Red Marl in Cheshire the drift sands and gravels are more developed than the Boulder-clay ; often they lie directly upon the marl without the intervention of any Boulder-clay. I have observed this also in Shropshire. High-Level Sands and Gravels. At Moel Tryfaen, Carnarvonshire; at several places in Flintshire (Moel-y-Crio among them) ; between Minera and Llangollen, Denbigh- shire ; at Gloppa, near Oswestry ; at the Setter’s Dog, near Maccles- field, and the Three-Rock Mountain, near Dublin, sands and gravels are found varying from about 1000 to 1400 feet above the sea-level. These sands and gravels contain shells of mollusca, speaking generally, of a similar facies to those fragments found in the Low-level Boulder- clay and sands. More perfect specimens have been found at these high levels, especially at Gloppa, by Mr. Nicholson, F.G.S., than 1 Quart. Journ, Geol. Soe, vol. xxxix. pp. 88-132. T. Mellard Reade— Glacial Geology. 313 are generally met with in the Drift of the plains. Drift with shells is met with at various places at levels intermediate between the Low-level Boulder-clay and sands and the High-level sands and gravels. This Drift is usually laminated and current-bedded. At Moel Tryfaen, where I devoted a good deal of study to the Drift, there is a much greater preponderance of erratic stones, such as Lake District rocks and Scotch granites, flints supposed to come from Antrim, with an admixture of Carboniferous limestone which may be from Anglesey, and true Anglesey crystalline schists, than is con- tained in the Drift of the coastal plain which reaches from sea level up to the 400 feet contour. It is rather a remarkable fact that in this high-level Drift I found a piece of Shap Fells rock in the form of a rounded pebble identified by Mr. Alfred Harker, F.G.S., as from one of the numerous offshoots of the granite mass of Shap Fells. I mention this specially because during the whole time I have been observing I have never met with any Shap Fells granite on this side of the Pennine Chain, either in Lancashire, Cheshire, or North Wales. The High-level sands and gravels of Tryfaen are overlaid on the eastern side of the excavations with a stony Till, evidently of local derivation, and containing nearly all local rocks. In one place a laminated bed of the sands inosculated with the Till, which also contained pockets of the sand. This is a very striking feature which has only been developed of late by the progress of the excavations. The stones contained in the sands and gravels are much waterworn, and there is a very much smaller proportion of them striated than what we find in the Low-level Boulder-clay. The grains of sand are also much rounded, waterworn, and polished. The Till also contains a proportion of these highly polished grains, and I found on washing some of the locally formed Till lying at a level of 800 feet above the sea, between The Rivals and Mynydd Carnguwch, that this also contained highly worn and polished quartz grains. Drift of the Coastal Plain adjoining Tryfaen. The Drift of the coastal plain adjoining Tryfaen is well exposed in coast sections, and consists more largely of material from the Snowdonian Range, both as regards boulders and the matrix, which is largely made up of the debris of slate rock and small slate flakes. An arched stratification is seen in some of the sections. The Till can be examined in numerous sections cut by the streams through the coastal plain, and a strict search almost everywhere yielded pebbles of Eskdale and other erratic granites, but seldom any fragments that could be described as “ boulders.” Mechanical analyses of twenty samples of the Till from various localities, with one exception, yielded the rounded and polished quartz grains. In some cases I found small shell fragments, and ample evidence was accumulated that the drift of the coastal plain was an intimate mixture of the debris of the Snowdonian rocks and erratic material from the North, and in some cases from Anglesey. Tracing the coast sections south-westwardly, they gradually put 314 T. Mellard Reade—Glacial Geology. on a more distinctively marine character, until at Nevin they assume the ordinary form of stratified drift-sands with shell fragments. Significance of the polished quartz grains. It will be necessary to turn aside here to point out the value I attach to the discovery of the prevalence of rounded quartz sand in the Till. I have been making a very exhaustive examination of sands from various parts of the world, and I find that contrary to received ideas marine sands are, on the whole, much more rounded than river sands. Indeed, river sands are generally little rounded, and, excepting in a river like the Amazon, I can find no parallel to the rounding of the grains of sand now dredged from the Irish Sea. Blown-sand of sand-dunes is not distinguishably more worn than the sand of the shore from which it is derived. When we find these highly-polished grains mixed up with angular and little worn fragments of Snowdonian rocks forming the bulk of the Till of the coastal plain, it is evident that they are of sea origin, and serve as certainly as the fragmentary shells of Molluses to declare this fact. I consider this an important discovery, which may, taking surrounding conditions into consideration, help to settle many dis- putes as to the marine or freshwater origin of certain deposits. In the present case, of course, the rounded grains can tell us no more of how they got to the high-levels than the shells of the Molluscs, but more of this presently. Distinction between the Marine Drift of the Plains and Mountain Drift. Where the Marine Drift of the plains approaches a mountainous district, and the base can be seen, it usually lies upon a Till made up almost wholly of local materials derived from the mountains. In some cases the Marine Drift is absent. At various points along the coast of Merionethshire, and in Mid-Wales, the local Till is prominently displayed in coast sections, but where a large estuary valley opens out on to the coast, and sections display the nature of the Drift, we find, as in the neighbourhood of Towyn, distinctly Marine Drift in some places, and a mixture of Mountain and Marine Drift in others. The stony Till clings to the mountain sides, the Marine Drift comes in more strongly as it is distant from the mountains. This is a rule to which, personally, I have seen no exceptions. Theories of Origin. Most of the details upon which the preceding sketch is founded, with the exception of those relating to the North and Mid-Wales coast, have been published. It is very necessary that details should be published, but the Drift is so complicated that it is very difficult, if not impossible, to describe it geologically in the sense that other formations, both older and younger, can be described. It is this that has beset the path of most glacialists. and the attempts to reduce the Drift deposits to geological order and system have been the fruitful source of many failures. , T. Mellard Reade—Glacial Geology. 315 So far as the Drift in the districts described in these pages is concerned, I long ago arrived at the opinion that no good could be got out of it—that is, no intelligible story—until we recognized it as one series of glacial deposits. On this principle, with the facts already stated before us, I propose to discuss the two opposing theories of the Glacial Drift, namely, the land-ice and the glacio- marine or submergence theory. The Land-Ice Theory. The present form of this theory postulates that during the period when the Drift, as we see it now, was formed, the relative levels of the sea and land were the same as now, and that a great ice-sheet advancing from the North over the Irish-Sea bottom ploughed out the deposits, re-arranged them, and pushing them before it, or conveying the materials frozen in the bottom of the ice, spread them over the lowland plains, and even pushed the sands and gravels with shells up to the high levels in the instances already named. ‘To the obvious objection that the Drift bears indisputable signs of aqueous deposition, it is answered that the current-bedded sands and gravels are due to the washing from the melting of the ice at the termination of and underneath the Mer-de-glace. Physical conditions involved. Before describing what the deposits themselves have to say to this theory, let us picture to ourselves what it as a matter of physics involves. The gathering ground of such a glacier could at first only be the land area which, by the terms of the postulate, was the same as now. A glance at the Map of the British Isles is sufficient to show that the snow-field could not have been above double the area of the sea it had to displace. The ice-front advancing over the Irish Sea would have had an average length of one hundred wiles. The waste by melting would have been enormous, so that an intensity of glacial conditions far in excess of those of Greenland of the present day would have to be granted. Probable Effect on the Sea Bottom. If, however, for the sake of discussing the question, we grant both the necessary conditions and their result, the ice-sheet, what would be the probable effect on the sea bottom? Unfortunately we have very little to guide us, for it is one of the weakest places in this theory that there are no analogous modern examples that we can appeal to. Hven with those glaciers that displace the sea from an inlet like the Malaspina Glacier of Mount St. Elias in Alaska,’ it is impossible to say what effect the glacier has had on any deposits that may previously have occupied the bottom. We know, however, that glaciers frequently over-ride loose deposits on land without displacing them, while in others they erode their beds. By the terms of the postulate Pre-glacial deposits must have occupied the Trish Sea before the over-riding of the ice-sheet bringing its load of 1 Israel Russell,—National Geographic Magazine, May, 1891. 316 T. Mellard Reade—Glacial Geology. . northern rocks along with it. A short Iceberg period must have preceded the final development of the Ice-sheet, even on this theory, and the products of this interval might get ploughed up and mixed with the products of the Ice-sheet. But what has become of the Pre-glacial deposits? I have examined most artificial exposures in Lancashire and Cheshire calculated to throw light upon the subject, but nothing in the form of a Pre-glacial deposit have I ever seen. The Alexandra Docks at Liverpool and the Docks at Garston gave grand opportunities for inspecting the rocky floor below tide level, the Mersey Tunnel also, in a lesser degree, but everywhere the glacial deposits rest directly on the bed-rock or the debris of the bed-rock. Borings at Widnes and well and shaft sinkings at various places in the Mersey Valley, all below the level of the sea, tell the same story. So far as we know, and I have seen nothing recorded to the contrary, the glacial deposits, with local variations, are the same from the top to the bottom of the series. The “Gully Gravels” lying in depressions down to 160 feet below the sea level are glacial, as shown by the rocks from which they have been derived being the same as those in the Boulder-clay. If, as is con- tended, the Drift of Lancashire and Cheshire is ploughed-up Irish- Sea bottom, it is very remarkable that it possesses such homologous characteristics throughout, and that the Pre-glacial deposits have been so thoroughly mixed with the materials brought by the land- ice that there is no distinguishable difference from the top to the bottom of the series. Not only are Pre-glacial deposits not to be found in situ, but not a scrap or shred of anything of the sort have I ever found embedded in or associated with the Boulder-clay. ; Areal Distribution of Erratics. Not only are the rocky materials contained in the Drift not arranged in any discoverable vertical order, but well recognized types of rock have a wide areal distribution. All over Lancashire, Cheshire, and Shropshire, Scotch and Eskdale granites are to be found in large boulders now scattered over the surface, while smaller boulders and pebbles of the same rocks are to be seen in the Drift itself. Hast and west they extend also from the Pennine Chain across Lancashire and Cheshire and along the coast of Wales to beyond Moel Tryfaen, in Carnarvonshire. If all these boulders have been conveyed to these points by an ice- sheet, some reasonable explanation of how it was done ought to be given. This hypothetical ice-sheet is supposed to have originated in Scotland, and to have been reinforced by glaciers from the north- west of England and the north-east of Ireland. Its course was over the bed of the Irish Sea to Liverpool Bay, at which place it divided into two lobes, one of which flowed onwards over Cheshire and Shropshire, and the other flowing westward, skirted the coast of Wales. Taking Criffel as the origin of the Scotch granite, it would form the apex of a triangular area over which this granite has been distributed, having a base—measuring east and west along the coast of Wales—as long as its sides. T. Mellard Reade—Glacial Geology. 317 The divergence of flow from Criffel will thus have been as great as 40 degrees, a very improbable thing to have happened with an ice-sheet traversing a basin fed from three sides. But when we consider that Lake District granites are found all along the same base, the improbability becomes to my mind an impossibility ; for it would involve, first, a concentration and mixing of the two differently-derived rocks on or in the ice-sheet, and their after dis- tribution in a fan-like form. This is omitting from consideration the further difficulty of the Antrim flints and other erratic rocks found over the same area. High-Level Sands and Gravels. Not only does the land-ice theory fail to explain the areal distri- bution of erratics, but we have the further difficulty to contend with that they are found at all levels up to 1400 feet above the sea. They are, as already pointed out, proportionally greater in numbers at the top of Tryfaen than in the Drift of the coastal plain of Car- narvonshire. As a question in dynamics it has never been shown what gradient would be required for an ice-sheet from the North thus to overpower the native glaciers of Snowdonia. The Welsh mountains are higher than any in the South of Scotland, so that to overpower the thrust of the ice northwards from a Snowdonian centre, and to deflect it south-westwardly, an enormous pile of snow would have to be concentrated in Scotland.