Extracts from the Proceedings for 1871-1872 (Session 14)
Mr. THOMAS NAISMITH exhibited a fine collection of Corals, Crinoids, &c., chiefly from the Carboniferous limestones of the West of Scotland, and gave some interesting notes on the nature and affinities of these organisms, and their representatives in the Polypi, Sea-Anemones, Sea-Urchins, and Starfish of the present seas.
Mr. JOHN BURNS submitted a specimen of Fossil Wood from Auchinlee Quarry, being portion of a trunk which was found embedded there, under 60 feet of sandstone. He called attention to the fact of the woody structure being very perfectly preserved in this specimen, and stated that portions of it when burnt emitted a little flame. He had pleasure in intimating that Mr. Yates, the contractor, from whom he had received the specimen, had kindly presented it to the Society’s Museum.
The CHAIRMAN [Mr. John Young, Vice-President] said Mr. Naismith’s collection was of much interest, as illustrating several extinct groups of Radiated animals which abounded in the seas of the ancient world. The Crinoids, or “stone lilies,” which were fixed to the sea bottom by a jointed or flexible stalk, were especially abundant during the Palaeozoic period, but are now represented by only a very few living forms, one of which had recently been discovered in the course of the deep-sea explorations that had been made in the bed of the North Atlantic. With regard to the fossil wood brought under their notice by Mr. Burns, although remains of plants were not uncommon in our Carboniferous strata, yet specimens showing the original woody structure were so rare as to make it desirable that every such one that was found should be preserved for microscopical examination. The one before them would be carefully examined in this way; but meantime he was inclined to regard it as belonging to the Coniferae, which were the only exogenous trees yet discovered in our coal measures. These Coniferae seem to have grown upon more elevated tracts of ground than the Lepidodendra, Sigillariae, &c., found in connection with our coal seams, and to have been carried down by floods, and so embedded in the sandstone strata, where they are now found. Whether they all belonged to the same genera or species, could only be determined by carefully-prepared microscopic sections. He conveyed the thanks of the meeting to the exhibitors and to Mr. Yates.
Mr. CHARLES LAPWORTH, of Galashiels, read a paper on “The Silurian Bocks of the South of Scotland.” The paper was illustrated by a map and sections, and a copious collection of fossils. At the close, a cordial vote of thanks was awarded to Mr. Lapworth for his kindness in reading the paper to the Society.
The paper (published in Transactions, Vol. 4, 1874, pp. 164-174) deals with the rocks and fossils of the Lower, Middle and Upper Silurian in southern Scotland; the following extract is the outline of Charles Lapworth’s introduction to the paper:
The author began by calling attention to the fact that the geological framework of Scotland is essentially composed of rocks of Silurian age, which occupy almost the whole of the northern and southern divisions of the country, and form in the centre a comparatively small synclinal hollow or basin, which is filled up by deposits belonging to the later systems of the Old Red Sandstone and Carboniferous. It thus becomes one of the first problems in Scottish Geology to ascertain the order of succession among these Silurian strata, to endeavour to read the history of its life system, and in general to obtain means for a comparison of the formation with the Silurian of other countries. To this problem the crystalline and metamorphic rocks of the Highlands can never furnish the key, which must therefore be sought among the comparatively unaltered and more fossiliferous deposits of the Southern Uplands. Here, however, we are at once brought face to face with what seem at first to be insurmountable difficulties. There is an almost complete identity of mineral character throughout the whole series; there are great thicknesses of strata from which fossils appear to be wholly absent; and, to crown all, the beds have been thrown into such a multitude of wrinkles and plications, so disturbed and inverted, that it is impossible to say on physical evidence alone, in a traverse of any distance, whether we are ascending or descending in the order of the strata. With these obstacles in the way of their thorough investigation, it becomes at once evident why so little, comparatively speaking, is known concerning them.
Nevertheless, a certain general arrangement of the strata may be said to be clearly ascertained. The lowest beds appear to form an axial or central mass of rocks, probably composed of strata of Cambrian and Lowest Silurian age, which dip N.W. and S.E. from an axial line running S.W. from Jedburgh to Kirkcudbright. To the north of these succeed a series of carbonaceous shales, of Llandeilo and Lower Caradoc age, which, together with an overlying mass of Upper Caradoc and Llandovery strata, undulate over the whole of the country lying between St. Abb’s Head and the Mull of Galloway; while the district stretching from the central Cheviots to Kirkcudbright is composed of Upper Silurian strata, the northern equivalents of which pass up conformably into the Old Red Sandstone, in a few inliers that protrude through the Carboniferous of the Central Basin.
Mr. Lapworth then traced the history of discovery among these rocks, from the time of Dr. Hutton to the date of Professor Geikie’s exhaustive paper on the whole subject, read before this Society in 1867. [Published in Transactions, Vol. 3, 1871, pp. 74-95.] Since that paper was published the fossiliferous districts of Girvan and Wanlockhead have been mapped and described by the Geological Survey, the Pentland beds have been more fully investigated, and the rocks of the eastern districts, comprising the Gala Group, Riccarton Beds, Hawick Rocks, &c., have been examined and described by the author and his friend Mr. James Wilson.
The Rev. WILLIAM FRASER, LL.D., of Paisley, corresponding member, read a paper on “Some Recently-exposed Sections in the Paisley Clay-beds, and their Relation to the Glacial Period.”
Mr. JOHN YOUNG, Vice-President, agreed with the author as to the general succession of the beds described, with the exception of the so-called overlying bed of upper boulder clay. He would suggest that, in the centre or neighbourhood of a town like Paisley, where excavations had been going on for a long time past, it was possible that diggings into the lower boulder clay may have been removed and laid down over more recent deposits; or former excavations into the hillside, flanked by the deposits in question, may have produced a slip of the boulder clay forming the crown of the hill, down over these more recent beds. He had seen an analogous instance during the excavations at Gilmorehill; and it was well known that geologists of eminence had sometimes been misled by surface deposits in the vicinity of towns, and the conclusions based upon these had afterwards been proved to be fallacious. He therefore urged caution in the acceptance of the view that this upper boulder clay had been laid down by ice subsequent to the formation of the shell-bed, which appeared to be of such recent origin. Mr. CRAIG was inclined to hold that the overlying boulder clay had been formed as Dr. Fraser had suggested. Other members having made a few remarks, Dr. Fraser briefly replied, and received a cordial vote of thanks for his paper.
An abstract of Rev. William Fraser’s paper appears in Transactions, Vol. 4, 1874, pp. 178-181; it is here quoted in full:
AFTER alluding to the progress which had been made of late years in the study of the glacial deposits, and to several important papers on the subject which had appeared in the Transactions of this Society, Dr. Fraser said he was persuaded that observers in this department were in the way of collecting data which would yet be of the greatest service in discussions as to geological time. He believed that a useful paper in that direction might be given, based on facts that had already been ascertained and classified. At present, however, he avoided these more important general questions, and confined himself to the statement of a few recent observations. The Paisley clays presented the following general order:—(1) Underlying all was the old boulder clay or till, the conditions of which were altogether unfavourable to life. It represented a cold, bleak, and in part tumultuary period. (2) Immediately above this was a laminated clay, whose texture was in every way distinct from the preceding. It was generally shell-less and stoneless, and in many instances beautifully and delicately laminated, the structure being at times so regular as to resemble the edge of a closed book, and specimens kept for a year or two had shown a texture and taken a polish like jasper. (3) Above the laminated clay, which was also useful in brickmaking, there occurred a thick bed in which shells of arctic and boreal types were found—Tellina proxima, Panopaea Norvegica, Pecten islandicus, Cyprina islandica, and others too numerous to specify. Geologists loved the layer for its shells, while the brickfield proprietors regarded it with an intense dislike. (4) Next in order was the clay chiefly used in brickmaking. In it the glacial shells are not to be found; the last which disappears is the Cyprina islandica. But in these clays, indeed in all above the laminated clay, small and large stones, up to boulders of several tons in weight, were abundant. In some instances they bear longitudinal scratches, but they are deposited so irregularly that their lines lie in every direction; showing that while the origin of the lines or striae may be ascribed to the period and the processes of the boulder clay, the transport and distribution of the materials were probably connected with subsequent movements, and especially with the melting of floating masses of ice. At the close of the formation of this clay series, and on its surface, appeared patches of a well-known shell, Mytilus edulis, the common mussel. (5) Terminating the series was a covering of varying thickness, and composed of various materials. There sometimes appeared near the surface a coarsely-laminated clay, which had occasionally been mistaken by observers for the more finely-laminated clay to be found at the commencement of the series. A long period, however, must have intervened between the two, and he suggested a careful scrutiny as to the phenomena connected with these two distinct clays.
Dr. Fraser then called attention to some facts which had recently come under his notice, showing, as he believed, that long after the period represented as glacial, and after the last of the clays had been deposited as the resting-place of the common mussel, there were, occasionally, in the valley of the Clyde, agencies at work which have since ceased to operate, at least to the same extent, in our now milder climate. It had been generally supposed that the rounded heights or knolls in the Clyde valley, where the rock was not immediately beneath the surface, were composed of boulder clay, and that when the surrounding masses were swept off and the valley was scooped out, the hollows had been left to be gradually filled with the later clays. In at least one instance this theory could be shown to be erroneous. Oakshaw Hill, on which part of Paisley is built, and on the crest of which the Neilson Institution rises with its dome, well known by many of our seaward travellers, was understood to be formed in this way. Its summit is about 106 feet above the sea level, and it stretches in a gradual slope for about 800 yards from west to east. When digging a foundation on the side of this hill or ridge for the Free Library and Museum which Sir Peter Coats had so generously granted to the town, a section was laid bare of what appeared to be the true till or boulder clay; but, very unexpectedly, underneath it was found the brick clay common to the Clyde district, with a bed of Mytilus edulis resting on its surface. The shells were in a perfect state of preservation, and he [Dr.Fraser] had dug into the clay to a depth of 4 or 5 feet, satisfying himself that it was identical with the brick clay now occupying the highest place in the Clyde series. This shell bed was 64 feet above the mean sea level, and the height rising over it was 42 feet of what in ordinary circumstances would have been accepted as genuine till or old boulder clay. The question which immediately suggested itself was, how came this superincumbent mass of clay—boulder clay apparently—to be placed there? It must have been at a comparatively recent time, and by gentle movements, for the mussels that lived there had been undisturbed. He thought it probable that, as the shell bed lay on the verge of a slope which passed into a hollow or valley, on the one side between Oakshaw and Castlehead, and on the other between Oakshaw and Woodside, and which had evidently been occupied by the sea to a considerable depth, masses of ice, carrying portions of the boulder clay, had been stranded on that ridge, and melting, had left what constituted the new height of very much the same material as that which was deposited by the great ice-sheet at an earlier stage of the glacial period. Dr. Fraser then traced a gradual descent in the mussel beds from the height of 64 feet referred to, down to similar beds in Glendaruel, Kyles Of Bute. He had found one such bed under the late steeple at the Cross of Paisley, at a height of 40 feet above the sea level; another at the head of St. Mirren Street, at 32 feet; another in James’ Street, at 23 feet; and another in Causeyside, at a height of only 12 feet; while out in the plain, and nearer the Clyde, he had found a fringe of shells, sea-weed, &c., which marked the tidal limit, subsequent, of course, to the time when the lowest of these beds was formed. Taking these facts into account, and assuming that Professor Geikie was correct in his inference of a certain elevation of the district since its occupation by the Romans, he thought they might be able to estimate approximately the length of time which had elapsed since the mussel beds were formed at a height of 64 feet above the present sea level. He concluded by submitting the opinion that intermediate between the isolated and incidental formation which he had described, and the primary boulder clay, there was evidence of what might be called a secondary boulder clay. He had been confirmed in this opinion by a careful examination of what seemed to be the old or primary boulder clay in Arran, in the valley between Lamlash and Slaodridh [Sliddery]. When searching there for glacial shells, in that section specially described by Dr. Bryce in his excellent work on Arran, he had found two or three specimens of Astarte borealis, and a few fragments of others, in circumstances which rendered it improbable, he might say impossible, that they could have lived there. The texture and appearance of the clay led him to infer that it must have been formed during the glacial period, probably near its termination, but certainly long after the true or primary boulder clay had taken its place. He respectfully submitted these facts, in the hope that light might be thrown by other observers on points which were as yet confessedly difficult and obscure.
Extracts from the Proceedings for 1896-1897(Session 39)
Mr. JOHN R. STEWART exhibited a series of large Photographs of the Fossil Trees at Victoria Park, Whiteinch, which had been taken before the building was erected over them. As some injurious action was observed to be presently at work amongst these notable fossils, the Commissioners of the Burgh of Partick were very anxious to find its cause and a remedy, and had therefore sent an invitation asking the members of the Society to visit the trees, and if possible make a recommendation on the subject. A small committee was accordingly appointed to carry out the suggestion.
Four weeks later, the committee submitted the following report:
FOSSIL TREES AT WHITEINCH.
Report by the Committee appointed to advise as to the Preservation of the Fossil Trees within the Fossil House, Victoria Park, Whiteinch, belonging to the Commissioners of the Burgh of Partick.
Committee—John Young, LL.D., F.G.S., William Armour, C.E., Joseph Sommerville, and John Dansken, F.S.I., F.R.A.S., Vice-President, Convener.
As instructed at the October meeting of the Council of the Geological Society of Glasgow, the members of the Committee visited the Fossil House at Victoria Park, met Commissioners Bowie and Brown, and the Superintendent of the Park, heard them as to the preservation of the Fossil Trees, and, specially, as to the propriety of introducing artificial heat within the building. The Committee examined the Fossils and their surroundings and having fully considered the matter beg to report unanimously— (1) That no artificial heat should be introduced into the Fossil House. (2) That the preservation of the Fossil Trees would be best secured by adopting means to prevent the inflow of rain and underground water into the Fossil House. It is suggested that a trench should be dug on the north and south sides of the house, keeping clear of the foundations, and making it deep enough to prevent the inflow of water to the house, and with sufficient declivity to allow the water to run off immediately to the west. The Committee is of opinion that it would not be needful to cut the trench deeper than the bottom of the lowest bed that enters the house. Should the Burgh Commissioners entertain the above suggestions the Committee would be glad to advise with them as to the most economical method of carrying them out.
(Signed) JOHN DANSKEN, Convener of Committee. 11th November, 1896
There is no further discussion concerning this report recorded in subsequent Proceedings.
Captain CROWTHER, sailing-master of the “Windward,” the ship which lately had the privilege of bringing home [to Norway from Cape Flora, Franz Josef Land] the Arctic explorer, Nansen, was introduced to the meeting, and exhibited a number of specimens of rocks and minerals, which he had picked up about lat. 79 N. by long. 48 E. Some of Cone-in-cone, though larger than Scottish examples, were in other respects very similar to them.
More information on Nansen and the Fram expedition of 1893-1896 can be found on the Fram Museum website.
Mr. GAVIN M. PRATT, Assistant Hon. Secretary, exhibited, for Captain Crowther, sailing-master of the “Windward,” specimens of Rocks and Fossils from the Arctic regions, collected on her recent voyage. They comprised Silicified Pine-wood, Crystallised Carbonate of Lime, Rock showing Cone-in-cone structure, from Cape Flora, Septariated Clay-nodule, Felstone Porphyry Boulder, Silicious Pebbles, Lead Ore (Galena) with Silver, from Cape Farewell, Greenland.
Mr. JOHN HORNE, F.R.S.E., F.G.S., of H.M. Geological Survey, and President of the Edinburgh Geological Society, read a paper on “Graptolites as Indices of Stratigraphical Horizons.” At the outset, after briefly reviewing the recent researches of Lapworth, Ruedemann, Nicholson, and Marr, on the morphological development of graptolites, the author proceeded to indicate the distribution of the group in time. He referred to the physical and palaeontological evidence in the Silurian basin of Bohemia which led to the well-known doctrine of colonies advocated by Barrande, and showed how this theory failed to explain the anomalies—palaeontological and physical—of the Silurian uplands of the South of Scotland. The researches of Prof. Lapworth, based on the vertical distribution of the graptolites, had placed the order of succession of these strata on an impregnable basis. The subsequent discovery by the officers of the Geological Survey of a zone of cherts, charged with Radiolaria, and analogous to the Radiolarian ooze of existing seas, had likewise proved of great service in unravelling the complicated structure of the Southern Uplands. These cherts, which underlie graptolite shales of Upper Llandeilo age, rest upon a series of Arenig volcanic rocks. It has now been conclusively proved by Professor Lapworth’s prolonged investigations that certain species of graptolites are restricted to certain definite horizons, and this has enabled geologists to correlate, more successfully than hitherto, the Silurian rocks of Great Britain with those of other regions. The lecturer paid a high compliment to the work of a member of the Society, the late Mr. James Dairon, amongst the Scottish graptolites, and expressed the hope that other members might continue the examination of the graptolite zones of the Southern Scottish Uplands.
The paper was illustrated by a large series of maps and diagrams, and by drawings and sections thrown on a screen by the oxyhydrogen lantern. At its close remarks were made by Dr. John Young, F.G.S., Mr. James Thomson, F.G.S., and the Chairman (Mr. Neilson), and a hearty vote of thanks was awarded to Mr Horne for his kindness in coming from Edinburgh to address the Society.
The HON. SECRETARY (Mr. Murdoch) referred to the recent death of Mr. William Kirkland, the first secretary of the Society, from the effects of an accident which he met with in Argyll Street. He was one of the four young men, members of a Literary Society connected with Free St. Peter’s Church, who met on 10th May, 1858, and drew up an advertisement calling a meeting of those willing to join a society for the study of geology. A subsequent meeting held on 17th May resulted in the formation of this—the Geological Society of Glasgow. Mr. Kirkland did much arduous work in the launching and carrying on of the new venture. Though soon retiring from the secretaryship he, up to the last, took a warm interest in its welfare.
Mr. JAMES THOMSON, F.G.S., made some remarks upon his remembrances of the deceased gentleman, and proposed a motion of regret at his untimely death. He also proposed that an extract from the minutes should be sent to Mr. Kirkland’s nearest relatives, and this being seconded by Dr. John Young, F.G.S., was unanimously agreed to.
Mr. JOHN SMITH read a paper on “The Exploration of a Rock-shelter and Shell-mound on the Carrick shore of Ayrshire.” This natural sea-cave in the red sandstone has a level of 10 to 12 feet above storm-tides. It has a peculiar set of “seats” or benches on its floor, which have been hewn from the solid rock, having all their front faces segments of circles. The makers of these curious “seats ” do not appear to be represented by any other traces of their occupation of the cave, but the subsequent inhabitants—the race which accumulated the shell-mounds found at intervals all round our coasts—had made use of it for a long period of time, as may be seen from the debris which entirely covers the floor and “seats,” in places to a considerable depth. Excavations yielded numerous bones of animals, including those of the ox, pig, sheep, rabbit, and various fishes, and shells of many edible molluscs. There were also fragments of hand-made and wheel-turned pottery. Except several broad-headed iron nails, and a fragment of sheet copper there was no metal, and there were no implements or articles of human use except a piece of pottery, the edges of which showed signs of its use as a “scraper,” and a fragment of dogfish bone, apparently used as an awl. After discovering the stone “seats” Mr. Smith communicated with the late Mr. Cochrane Patrick, who said that in all his experience he had never met with a similar example. This feature of the Carrick cave may therefore be pronounced unique in Scottish archaeology. The paper was illustrated by some fine photographs taken by Mr. Robert Dunlop, and by the author’s own drawings.
Extracts from the Proceedings for 1922-1923 (Session 64)
Mr. C. J. GREGORY read a paper on “Parallel Roads at Loch Tulla.”
In the discussion Mr. DAVID KERR said that although he had been at Loch Tulla he had never seen any trace of parallel roads on the hill. Mr. ALEX. STEVENS pointed out that such traces on a hill might be seen with difficulty unless one chanced to have the right angle and point of view. Mr. MURRAY M‘GREGOR, on the other hand, referring to the coincidence of two papers on the same subject being read by Mr. Gregory and Mr. Bailey in Glasgow and Edinburgh within the same week, said that the “roads” were easily seen. Mr. Bailey had described two roads at 1041 feet and 830 feet. Mr. TYRRELL, referring to the enormous glacial lakes that had been traced over the present site of the great lakes of North America, said that conditions must have obtained at that time quite unlike the present day, because nowhere in glacial regions had we anything approaching the magnitude of these lakes. The President also spoke some words in compliment to Mr. Gregory, and congratulated him on his first paper to the Society.
The talk given by C.J. Gregory (who was the son of Professor J.W. Gregory) appears in Transactions, Vol. 17, 1927, pp. 91-103. The following extract is part of the introduction to the talk:
The Parallel Roads of Glen Roy, for long a mystery to men of Science, have received so complete and natural an explanation, due especially to Macculloch, Agassiz, and Jamieson, that one was led to wonder whether water might not have been impounded by ice in a similar way elsewhere in the Highlands, with the formation of similar beaches. Many cases occur of alluvium laid down by glacial lakes, sometimes with the formation of low terraces, but hardly any high level beaches have been traced out comparable with those of Glen Roy. While passing along the west Highland line between Tyndrum and the Moor of Rannoch and along the road from Bridge of Orchy to Kingshouse, Professor Gregory had several times noticed three such terraces, and found beach material upon them. He suggested that I should determine their height and extension, and I had the opportunity to do so in April of 1921. During the very next month, Messrs. John Mathieson and E. B. Bailey undertook the same operation. With [certain] exceptions, our work is in agreement, but as they used a theodolite the heights they obtained by triangulation must be accepted as far more nearly correct than my aneroid observations. Their results have been presented to the Geological Society of Edinburgh.
Mr. G. W. TYRRELL gave an address on his recent work in South Arran. Mr. Tyrrell pointed out that south Arran is probably unique as a field for the study of igneous intrusive geology. As Harker has drawn attention to the occurrence in Skye of Basalt and Felsite, with Basalt in patches through the Felsite, and often the two rocks mixed to an intermediate type, so also in south Arran. This is well seen in the Ross and at Squiler, where the sequence runs—Basalt, Felsite, Basalt, Felsite, Dolerite, Sandstone, Felsite, Dolerite, Sandstone. Mr. Tyrrell believes that these great intrusions took place in successive stages, forming what is called a Cedar Tree Laccolite, well seen in Monamore Glen. On one aspect the thinned-out edges of the intrusion can be separately traced, whereas on the other aspect the intrusion is apparently in one mass. Examination in detail, however, shows an absence of the variation in size of crystals which one would expect in a massive intrusion. One of the interesting details of Mr. Tyrrell’s lecture was the working out of the age of the intrusion at King’s Cross, where there have been successive intrusions of Clauchland Sill, then Granite and Felsite, next Pitchstones, and lastly Basalt.
Mr. DONALD PATTON, in congratulating Mr. Tyrrell, drew attention to the new light this work threw on such massive intrusions as Tinto, where for 2000 feet we have a fine-grained Felsite. Mr. BEGG, Mr. YOUNG, and Mr. M‘LEAN complimented Mr. Tyrrell on his most interesting paper, and on Mr. Begg’s motion a hearty vote of thanks was accorded.
Dr. ROBERT KIDSTON, F.R.S., delivered a lecture on “The Fossil Plants of the Rhynie Chert Bed,” discovered by Dr. Mackie. Dr. Kidston had already given three lectures to this Society on the four plants of the Chert, so that a certain amount of the lecture had already become known to our members. Dr. Kidston, however, had many new section photomicrographs to show, and a good deal of new and highly interesting information with regard to fungal parasites of the plants. The preservation of the structure in most of the slides was almost beyond belief. One of the new photographs showed a stoma in plan, and the lecturer pointed out how in all the vast time that has elapsed since the Middle Old Red Sandstone no perceptible change has taken place in the structure and appearance of the stomata. In proposing a vote of thanks, Dr. GREGORY referred to the distinguished researches of Dr. Kidston in palaeobotany, and said that the Rhynie work rounded up a long list of discoveries of which Scottish Geology was proud.
Dr. Kidston was President of the society during Sessions 60, 61 and 62. For an account of his presidential address, “An Old Red Sandstone Plant: its Structure and Mode of Occurrence”, see Session 60, extract from the meeting held on January 10, 1918, which can be found in the extracts from the Proceedings.
Papers were read by Messrs. E. M. ANDERSON, M.A., B.Sc, and H. H. READ, B.SC, A.R.C.SC, officers of H.M. Geological Survey. Mr. ANDERSON’S paper dealt with his own observations of the Schiehallion Country. By means of a large coloured map and list of the rock sequences he explained in a lucid manner the general conclusions he had come to in regard to the build of that part of Perthshire, particularly in reference to the rock systems on the two sides of the great quartzite ridge of Schiehallion. In commenting on the paper, the President referred to the complexity of the subject and to the perennial interest of the problems presented by the geology of the Highlands.
Mr. READ’S paper, which was also highly technical in character, dealt with what he calls “Contaminated Magmas of Aberdeenshire.” These are magmas which have incorporated sedimentary material as distinct from a true primary magma. Mr. Read was able to show that in north-east Scotland magmas of noritic character may by contamination give rise to abnormal rocks containing Cordierite, Spinel, Sillimanite, Biotite, Hornblende, Andesine, Orthoclase, Garnet, Quartz. Mr. Read has studied rocks, however, that show normal granitic structure, and he has put forward a hypothesis to show how the sedimentary Xenoliths may have been removed. The Xenoliths, while in suspension in the liquid magma while it is basic, gradually receive heavy material from the magma, hence the denser Xenoliths sink in the liquid, and a clean, apparently normal rock is left. He has put forward, after long chemical analysis, a principle of selective assimilation to group and generalise these changes. He is thus able to show that, starting with a primary basalt magma, we may conceive how by gravitation and assimilaton all the at present known igneous rocks may have been produced. In the discussion Mr. TYRRELL referred to the great importance of these new ideas in igneous geology put forward by Mr. Read, and remarked that these discoveries supported his contention that Scotland was a unique country for the study of igneous phenomena. Mr. Read’s paper was illustrated by numerous lantern views and photomicrographs.
Extracts from the Proceedings of 1946-1947 (Session 89)
Dr. A. T. J. Dollar, A.K.C., F.R.S.E. [delivered] a lecture on “Methods of Studying Recent Scottish Earthquakes.”
Neither text nor abstract of this lecture appears in the volume of the Transactions (volume 21) in which the Proceedings for Session 89 were published. However, the transcript of a lecture on a related topic, given three years later by Dr. Dollar, was published in this volume (Transactions, Vol. 21, part 2, 1951, pp. 283-361): “Catalogue of Scottish Earthquakes, 1916-1949. By A. T. J. Dollar, Ph.D., A.K.C., F.G.S., F.R.S.E., Lecturer in Geology, University of Glasgow.” The lecture deals with a range of aspects of seismic activity in Scotland, including cause and distribution, intensity and damage caused, before giving the catalogue of 122 earthquakes.
To commemorate the 150th Anniversary of the death of James Hutton, which fell on 26th March, 1947, the following addresses, descriptive of his life and work, were given before the Society: (a) Hutton’s Life and Times, by Dr. Murray Macgregor; (b) Hutton’s Contribution to Dynamical Geology, by Dr. Murray Macgregor; and (c) Hutton’s Contributions to Igneous and Metamorphic Geology, by Dr. G. W. Tyrrell.
The two following papers were read:
“The Dyke Rocks of County Donegal and the adjoining part of County Tyrone, Ireland,” by M. Shirama Rao, B.Sc., M.Sc, F.G.S.
“Camptonitic Dyke Rocks from Inishowen, County Donegal, Ireland,” by M. V. N. Murthy, B.Sc., A.I.I.Sc., F.G.S.
These papers, abstracts of which appear in the present part of the Transactions, [Vol. 21, part 2, 1951] pp. 203-206, were based on a detailed petrographic study carried out by the authors on a collection of dyke rocks made in County Donegal by Dr. W. J. McCallien, formerly of the Geological Department of Glasgow University. Mr. Rao dealt with the Caledonian and Tertiary dykes and Mr. Murthy with the camptonitic dykes to which a Permian age is assigned.
Referring to Mr. Rao’s paper Dr. G. W. Tyrrell emphasised one of the most striking features of the Caledonian dykes, namely, an almost complete transition between lamprophyres and porphyrites. The transition had been noted before in the Caledonian dykes of Glen Etive, Ben Nevis and Glencoe, but nowhere was it more perfectly displayed than in the north of Ireland. With regard to the replacement phenomena mentioned by Mr. Rao, Dr. Tyrrell said that he regarded these as primary in the sense that they were produced by the last juices of the magma, rich in water and other volatiles, reacting with the already crystallised material. Finally, as regards the olivine-tholeiites there was what seemed to be a contradiction in terms. Analyses showed that these rocks were either on the border line or slightly over-saturated. This was due to the early crystallisation of the olivine not having taken out of the magma so much silica as the felspars and pyroxenes, so that some silica was stored up and appeared in the analyses as an excess.
In commenting on Mr. Murthy’s paper Dr. Tyrrell pointed out that his investigations dealt with rocks the age of which had been in doubt until Professor Holmes had demonstrated by radio-active methods that they were unquestionably of Permian age. The correctness of this ascription had been confirmed by Mr. Murthy’s work.
Some information about Dr. W. J. McCallien, on whose initial studies the above research was based, can be found in the Anniversaries page: see the meeting held on October 8, 1970 in the extracts from the Proceedings for Session 113.
Extracts from the Proceedings for 1971-1972 (Session 114)
Dr. Gordon Biggar (University of Edinburgh) delivered a lecture entitled ‘Lunar geology and experimental petrology’.
The scale of major lunar surface features was related to familiar features on the Earth e.g. some of the mare are smaller, some bigger, than Ireland. The impact origin of the lunar basins resulted in the formation of complex breccias. The lava lakes filling the basins were later events.
Experiments left on the surface by astronauts still record information on the Earth’s polar wobble (and related earthquakes), continental drift on the Earth, the lunar atmosphere, solar wind, meteorite impacts on the moon, moonquakes, and on lunar heat flow.
Mare-type basalts are the most clearly identifiable rock types. Texturally, plagioclase, olivine, pyroxene and titaniferous ores have crystallised together and experimental evidence at one atmosphere demonstrates that all commence to crystallize within about 20° C. Chemically they are characterised by low Na2O, high TiO2 (up to 12%) and a reduced state such that all the iron is ferrous and chromium is substantially chromous. These rocks are interpreted as the last few percent of liquid left near the top of a lava lake after 80 or 90% had crystallised. The low level of sodium and other volatile elements is due to volatilization into the near-vacuum above the moon.
A second suite of rocks contains anorthosites, gabbroic anorthosites, anorthositic gabbros and norite (all with low levels of volatile elements). These rocks do not have compositions corresponding to known liquids. Addition of Na2O and H2O to replace the amount lost by volatilization, and the application of slight pressure, does result in compositions from which plagioclase, olivine and pyroxene crystallise at much the same temperature. The origin of these rocks is not yet clear.
Stewart M. K. Henderson (1907-1972) was a geologist turned administrator. He removed to Glasgow from Brighton in 1926, when he entered the University to graduate B.Sc.with Honours in Geology in 1930. He was then nominated to the Baxter Demonstratorship, and pursued research on which he obtained the degree of Ph.D. in 1934. His original work was initially in palaeobotany, in the description of plants from the Old Red Sandstone of Callander; but when he applied himself to interpreting the Ordovician rocks of Girvan he entered a field that allowed him to make substantial advances in sedimentology. His mapping in difficult ground threw light on the sequence in greatly deformed rocks; and his analysis of sedimentary characters notably of the Ardwell Flags enabled him to discern and interpret what would now be called flame-structures, load casts, slump bedding, convolute bedding, and other signs of high-energy and turbiditic transport, and to recognise a contrast between ‘normal’ conglomerates and breccias, greywacke conglomerates, and breccias formed by the lubricated slipping and fracturing of sediments in an unstable environment; and he recognised the possibility of a seismic triggering of submarine slides as a cause of some of the structures.
He was diverted from pure research when he was appointed to Kelvingrove as Keeper of Archaeology in 1935. Thereafter he devoted his life to promoting museum affairs in Glasgow. After service in the R.A.F. during the War he became in 1946 Keeper of Natural History at Kelvingrove, and in 1947 Director of the Museum. He succeeded Dr. T. J. Honeyman in 1954 as Director of Museums and Art Galleries for the whole of Glasgow. He finally retired in 1972. The high national esteem in which his organising and administrative ability was held was marked in 1970 by his election as President of the Museums Association.
T. N. George
Extracts from the Proceedings for 1996-1997 (Session 139)
The first meeting of Session 139 was the occasion of the presentation of the T. Neville George Medal to Professor Bill Chaloner (Royal Holloway University of London). His subject was “Fossil Plants and Climatic Change.” The sedentary character of terrestrial plants gives them a direct and total dependence on the climate of their habitat. As a result, fossil plants offer a unique record of climate change through time. For as far back as plants can reliably be assigned to extant species, this “climatic signal” can be read with some precision. Fossil plants can also offer a basis for assessing changes in atmospheric composition, most notably carbon dioxide, which is linked through the “greenhouse effect” to global climate.
Professor Chaloner reviewed some of the recent results in this field.
1997 started with a lecture by Mr. Norman Butcher of Edinburgh. His topic was “1797-1997: The Legacy of James Hutton and Charles Lyell”. 1997 marked the anniversary of the death of James Hutton and the birth of Charles Lyell. These two major figures in Scottish Geology are recognised world-wide for their contribution to our understanding of the Earth. The lives and works of the two great geologists were compared and contrasted, their contribution to geology assessed as was the development of the Geological Sciences since their time.
The lecturer on 24th April was Dr. Godfrey Fitton (Department of Geology and Geophysics, University of Edinburgh). His talk was entitled “Ocean Drilling and the Icelandic Plume”. The North Atlantic margins provide a unique natural laboratory in which to investigate the role of mantle plumes in the break-up of continents and the formation of large igneous provinces. The opening of the ocean 60 million years ago was accompanied by the eruption of vast amounts of magma, most of which lie beneath the sea. The international Ocean Drilling Program has recently devoted two two-month legs of drilling to study volcanic rocks off the southeast Greenland coast. The results provide a detailed record of the initiation of the Iceland plume and the birth of the Atlantic Ocean.
RIVER AYR AND HEADS OF AYR: 14th June 1997
Leader – Dr. G.E. Bowes, formerly University of Glasgow
by Monica Thorp
On 14th June 1997, Dr George Bowes led a large party to the Ballochmyle Gorge near Howard Bridge, and then to the Heads of Ayr.
The River Ayr cuts a very attractive gorge through Permian (New Red) sandstone near Ballochmyle, which is now bridged by what is possibly the largest single-span masonry arch in the world, the Ballochmyle Viaduct, that carries the railway line from Glasgow to Dumfries. This remarkable example of early Victorian engineering was built in 1846-7 from quarries opened for the purpose of the gorge itself, so given both natural and artificial exposures we had excellent opportunities to work our way down the succession.
In the highest quarry we saw good examples of dune bedding orientated East to West, suggesting Saharan latitudes and the influence of the northeast Trade Winds. At river level we were shown a different fabric: a laminated sequence with occasional small lenses of cross-bedding (sections of ripple-marks), indicating that this was water-laid sand, probably in a transient lake in the desert. Coarser bands consist of secondary depositions typically wind-rounded ‘millet-seed’ sand grains. The sandstone was deposited on top of late Carboniferous-early Permian lavas, and working up the gorge and yet further down the succession we could see dark fragments of volcanic debris within the sandstone. Finally we reached the lowest level, at which perhaps 70% of the sediments consist of water-laid igneous debris.
Leaving Ballochmyle, we then travelled further through Burns country to the coast, into sunshine and back into Old Red Sandstone times, at the heads of Ayr. Here at the southern end of the bay are Devonian lavas and hydrothermal veins. Amygdales of deep blue-green chlorite, and veins of red jasper abound, and one small agate was found. Coming round the bay one moves up the succession into Old Red fluviatile conglomerates. These have been cut by tertiary dykes of the Arran dyke-swarm, which have been excavated by the sea to leave deep slots in the cliff, and baked margins. In the middle of the bay, steeply dipping cementstones, of Carboniferous age, have been downfaulted and are exposed below the Old Red cliff.
At the northern end of the bay is a large volcanic vent dating, like the lavas at Ballochmyle, from Permo-Carboniferous times. As we worked round the bay we first encountered water-laid tuff, then dykes running perpendicular to the high cliff, below which is an extensive wave-cut platform providing a horizontal section through that part of the vent. Across this, along faults, are intruded en echelon lenses of Tertiary (Arran) dykes. Outcrops of agglomerate show good examples of spheroidal weathering. By the time we got there the tide had covered what is thought to be a raft of sediments that fell into the vent and stayed there.
The most enjoyable day ended at a cave in the cliff where a substantial piece of what appeared to be wood is incorporated into the rock, suggesting that a tree growing on the edge of the vent had been caught up in the agglomerate during an eruption, and silicified.
Our thanks go to Dr. Bowes for an excellent excursion.