a hot climate. The only mode of getting over this discrepancy is to suppose that in those days the winter cold was very severe, and the summer heat intense, so that in the summer time the animals, now found in warmer regions, migrated northwards, and in the winter time those now found in the Arctic regions went southwards. The fourth group consists of such extinct forms as the Cave Bear, the Stag, the Mammoth, and the Woolly Rhinoceros. The fifth group includes the Sabre-toothed Tiger, the Irish Elk, Rhinoceros megarhinus and R. hemitœchus, and they, with some others, show that there is no great break between the Quaternary and the Pliocene, such as would warrant any sharply defined division of great value. The interest centered more particularly in the Arctic group; and so far as the evidence went, it seemed to be extremely probable that they were in occupation of the areas in Great Britain in which they were found during the time the other areas, in which they were not found, were covered with glaciers; and this period may be put down to that of the latest sojourn of the glaciers in the highest grounds of our islands, and even so far south as the districts of Auvergne and Dauphiné.

On the Progress of the Geological Survey in Scotland. By Prof. GEIKIE, F.R.S. When the British Association last met in Scotland, I had the honour of bringing before this Section a report upon the progress of the Geological Survey, from the time of its commencement here in 1854 by Professor Ramsay, under the direction of the late Sir Henry De la Beche, up to the year 1867, under the supervision of the present Director, Sir Roderick Murchison. During the four years which have since elapsed, considerable advance has been made in the survey of the southern half of Scotland; and I propose now, with the sanction of Sir Roderick, to present to you a brief outline of what has been done, and of the present state of the Survey.

At the time of my previous report rather more than 3000 square miles had been surveyed. Since then we have completed 2700 square miles additional, making a total area of nearly 6000 square miles. Of this area 3175 square miles have been published on the one-inch scale, and three sheets, representing in all 632 square miles, are now in course of being engraved. The whole country is surveyed upon the Ordnance Maps on the scale of six inches to a mile, and from these field-maps the work is reduced to the one-inch scale, which is the scale adopted for the general Geological Map of the country. In addition to that general map, however, maps on the larger or six-inch are published of all mineral tracts. In this way five sheets of the six-inch maps have now been published, embracing the whole of the coal-fields of Fife, Haddingtonshire, and Edinburghshire, with a large portion of the coal-fields of Lanarkshire, Renfrewshire, Ayrshire, and Dumfriesshire.

The area over which the field-work of the Survey has extended lies between the mouths of the Firths of Tay, Forth, Clyde, and Solway, eastwards to the borders of Roxburghshire and the mouth of the Tweed. It includes the counties of Fife, Kinross, the Lothians, Lanark, Renfrew, Peebles, Ayr, Wigton, Kirkcudbright, Dumfries, and Selkirk, with parts of Stirling, Dumbarton, and Perth.

Of the geological formations examined, the Lower Silurian rocks of the southern uplands cover a considerable space upon the published maps. Until three years ago the mapping of these rocks continued to be most unsatisfactory, owing to the want of any continuous recognizable section from which the order of succession among the strata could be ascertained, and to the great scarcity of organic remains. Our more recent work among the Leadhills, however, has at last given us the means of unravelling, as we hope, the physical structure and stratigraphical relations of the uplands of the south of Scotland. The rocks there are capable of division into several well-marked groups of strata, characterized by distinct assemblages of fossils. We have a lower or Llandeilo series, with a suite of graptolites, and forming probably an upper part of the Moffat group, and a higher or Caradoc set of beds, with a considerable assemblage of distinctive fossils. This higher group we believe to be on the same general horizon as the limestones of Wrae and Kilbucho in Peeblesshire.

The Lower Old Red Sandstone has now been mapped completely over the whole of its extent between Edinburgh and the south of Ayrshire. Fossils have only

been met with at one locality in the latter county, where Cephalaspis occurs. The most characteristic feature of the formation is the enormous development of its interbedded volcanic rocks. Between Edinburgh and Lanarkshire, also, there occurs in this formation a local but violent unconformability, connected probably with some phase of the contemporaneous volcanic activity of the region.

Most of the detailed work of the Survey has lain upon Carboniferous rocks. In the lowest formations of this system, known as the Calciferous Sandstones, the Survey has now been able to trace a twofold division completely across the country, from sea to sea, viz. a lower group of red sandstones, and a higher group of white sandstones, green, grey, and dark shales, cement-stones, limestones, and occasional coal-seams. All these strata lie beneath the true Carboniferous Limestone. They are becoming daily more important from their containing in some places highly bituminous shales, from which paraffin oil can be made. The Carboniferous Limestone series, with its valuable coals and ironstones, has been mapped, and in great part published, for the eastern and south-western coal-fields; and this is also the case with the Coal-measures. Much additional information has been obtained regarding the development of volcanic action in central Scotland during the Carboniferous period.

The Permian basins of Ayrshire and Thornhill have been surveyed and in great part published. Much fresh light has in the course of this Survey been thrown on the interesting Permian volcanoes of the south-west of Scotland.

Attention has been continuously given to the superficial accumulations. These are now mapped in as great detail as the rocks underneath, and plans are being prepared with the view to an issue of maps of the surface geology.

By a recent order of the Director-General, each one-inch map is now accompanied at the time of its publication, or as soon thereafter as possible, with an explanatory pamphlet, in which the form of the ground, geological formations, fossils, rocks, faults, and economic minerals are briefly described, and such further information given as seems necessary for the proper elucidation of the map. These pamphlets are sold at a uniform price of 3d. Detailed vertical sections are pubfished for each coal-field. For the construction of these sections, records of boring operations are procured and recorded in the register-books of the Survey. Since 1867 more than 312,200 feet of such borings have in this way been entered in our books. Sheets of horizontal sections on a large scale are likewise issued to form, with the maps and explanations, a compendium of the geological structure of each large district.

Another feature of the work of the Survey is the collection of specimens of the rocks and fossils of each tract of country as it is surveyed. Since my previous Report to this Section of the British Association, we have collected 1011 specimens of rocks, and 7500 fossils. These are named and exhibited, as far as the present accommodation will permit, in the Museum of Science and Art at Edinburgh.

The work of the Geological Survey is carried on, as I have said, under the guidance of its Director-General, Sir Roderick Murchison, a name which has long been a household word at the meetings of the British Association, and one to which I am sure you will permit me to make on this occasion more than a passing reference. While the Survey advances, as I have shown, steadily over the face of the country, unravelling piece by piece the complicated details of its geological structure, to Sir Roderick belongs the rare merit of having himself led the way, by sketching for us, boldly and clearly, the relations of the older rocks over more than half of the kingdom. Much must undoubtedly remain for future investigation, but his outline of the grand essential features of Highland geology will ever remain as a monument of his powers of close yet rapid observation and sagacious inference. At one time I had hoped that the Chair of this Section might be filled by him, and that we should be permitted to listen anew to his expositions of the rocks of his native country. There is no one among us who does not regret the absence of the familiar face and voice of the veteran of Siluria. We meet once more on Scottish ground, and for the first time we have not here with us the man who has laid a deeper, broader impress on Scottish geology than any other geologist either of past generations or of this. There is, however, on the present occasion, a special cause

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for regret. Only within the last few months he founded a Chair of Geology in the University within whose walls we are now assembled-the first and only chair of the kind in Scotland. It would have been a fitting and grateful duty on the part of the University to welcome one of its most distinguished benefactors. I am well aware, indeed, that this Section-room is no place for the obtrusion of personal sentiments; yet I would fain be allowed to add in conclusion an expression of my own deep regret at the recent illness and consequent absence of one to whom, over and above the admiration which we all feel for his life-long labours and his personal character, many years of friendly intercourse have bound me by the closest ties of affection.

Fossiliferous Strata at Lochend near Edinburgh By D. GRIEVE.

The strata to which this notice refers are situated on the east side of the Loch, and appear in the Trap precipice, on which stand the ruins of the ancient Keep of the Logans of Restalrig. Although it was conjectured, it was not known, until Mr. Grieve found distinctive fossils in these strata, that the Carboniferous formation, so largely spread over the site of Edinburgh and its neighbourhood, extended so far to the eastward; and it would now appear that these form a continuity of the strata and shales found some years ago on the north side of the Calton Hill They are of the Lower Carboniferous formation, and seem to be equivalents of the sandstones and shales of Burdiehouse on the south, and Wardie and Granton on the north and west of Edinburgh.

The fossils found by Mr. Grieve at Lochend he enumerates as follows:-Of Plants, Calamites of a large and well-marked species, a Lepidodendron and Lepidophyllum, with various Sphenopterites. Of Fishes, a beautiful specimen of the genus Palæoniscus; also scales, teeth, spines, and coprolites. Lastly, a Crustacean, Cypris Scoto Burdigalensis, or of an allied species.

It is to be regretted that the quarry from which the above fossils were obtained has now been obliterated in the course of agricultural improvements.

On the position of Organic Remains near Burntisland. By G. J. GRIEVE.

On "The Boulder Drift and Esker Hills of Ireland," and "On the position of Erratic Blocks in the Country." By Sir RICHARD GRIFFITH, Bart., F.R.S. Sir Richard commenced by giving a short description of his geological map, and mentioned that the direction of the mountain-ranges generally, as well as the strike of the strata, ranged from north-west to south-east. He stated that the position of Ireland with respect to Europe was further to the west into the Atlantic Ocean, and that on the west side were numerous deep bays, guarded by promontories composed of hard rocks, while on the east side the coast was only slightly indented on any part. He mentioned that the coast of Ireland all round was composed of mountains, while the interior was nearly flat, and that the rock of that plain was altogether composed of Carboniferous limestone. He stated that a line drawn from Sligo Bay on the west to Drogheda Bay on the east, would form the northern boundary of the great plain, while the southern boundary might be shown by a line drawn from Galway Bay on the west to Dublin Bay on the east, comprehending an area of 5000 square miles. This large district was divided into nearly two equal parts by the river Shannon, whose source was near Lough Allen, in the county of Cavan, elevated 160 feet above the level of the sea, while the length of its course to the sea, at Limerick, was 140 miles, giving an average fall of 1 foot 2 inches in a mile; and he further stated that this fall was not equally distributed, as between Limerick and Kildare, a distance of 12 miles, was a fall of 98 feet, showing that from the distance of 128 miles between Lough Allen and Killaloe, there was an average fall of less than 6 inches in a mile. The great centre plain, already described as containing 5000 square miles, contained 1,000,000 acres of bogs, each of which was surrounded by drift resting on the top of the

Carboniferous limestone, and it usually presented an undulating surface which occasionally affected the form of elongated elliptical hills, which usually ran parallel to each other. This fact was especially exemplified by Clew Bay, situated on the west coast, in which were upwards of 300 islands, the surface of which was composed of boulder-drift resting on Carboniferous limestone. He mentioned that at least on the eastern the boulder drift had a thickness of about 100 feet, but probably was much thicker towards the west. He described the boulder-drift as composed of a base of sandy or gravelly clay, which contained numerous rolled masses, huddled together in a confused manner without reference to size, and that their dimensions ranged between those of a small egg and two or three cubic feet in diameter. He next adverted to those remarkable ranges of hill, which varied in height above the surface of the boulder-drift from twenty to sixty feet, the ascent being usually about thirty degrees on the west side, but less steep on the east. These Esker hills were very numerous in the midland plain, especially in the counties of Mayo, Galway, and Roscommon, on the west side of the Shannon, and of the King's County and Westmeath on the east. Their general direction was from west to east; and one great Esker, which extended from west to east from the county of Galway to Westmeath, was used as the post road from Dublin to Galway, for a length of 30 miles. This great Esker crossed the river Shannon at Athlone, and was subsequently cut through by it, exhibiting a great shoal at the present time, on which the old bridge of Athlone was built. On the western side, about 50 feet above the river, an ancient fort had been erected to defend the passage, and this fort still remained in perfect preservation. The town of Athlone was also built on the east side of it, and extended from thence nearly 20 miles. Fifteen miles to the south of Athlone, the river Shannon was crossed again by another Esker, also running from west to east, and in this place the Esker presented very steep acclivities on either side. He last described a very remarkable Esker called the "Horseshoe," from its form, the north arm of which running eastward extended for 10 miles, whilst the southern extended 8 miles, leaving an opening of 8 miles, with the town of Clara in the centre. The slopes of these horseshoe Eskers on the west side were steep, having an angle of about 30°, while on the outer side the slope was only from 10 to 15°. Having mentioned that in many cases Eskers were observed, particularly to the west of Athlone, having a north and south direction, he gave it as his opinion that the Eskers were deposited on the top of the boulder-drift at a subsequent period, and that the materials, which were similar to the boulder-drift, with the exception of the admixture of sandy clay matter, were deposited from currents and waves in a shallow troubled sea, and possibly did not owe their existence to glacial action. Sir Richard next directed the attention of the Section to the occurrence of large erratic blocks, totally unconnected with the gravel, which were found resting on the surface throughout the entire district, from Galway Bay in an eastern and southern direction, passing over the summits of the Slieve-bloom mountains, near Roscrea, and extending from thence through the King's and Queen's counties. These blocks were all composed of a peculiar porphyritic granite from the district situated to the north of Galway Bay. This granite was composed of red and white felspar, grey quartz and black mica, and contained numerous crystals of red felspar, which rendered the appearance so peculiar that no doubt could be entertained that the granite blocks above mentioned were derived from the Galway district.

These blocks are usually angular though occasionally slightly rounded. One, whose dimensions was 10' by 5' by 3', equal to 4 tons in weight, is described by Mr. Joseph O'Kelly, of the Geological Survey of Ireland, as resting on Lower Silurian ground, 10 miles to the north of the Town of Roscrea, at an elevation exceeding 1000 feet above the sea; and his colleague, Mr. G. Henry Kinahan, the senior geologist, found great numbers of these blocks scattered over the limestone plain, in the neighbourhood of Athenry, to the east of Galway. He likewise described large blocks of the same granite in the valley of Glensascaul, at the western base of the Slieve-bloom mountains, the dimensions of one of which was 12' by 10' by 11', equal to 110 in weight, and others whose weight varied from 35 to 48 tons.

Sir Richard next alluded to another drift of erratic blocks, which took a course

from south to north, crossing the Curlew and Ox mountains in the county of Sligo, the direction of each being from north-east to south-west.

The Curlew mountains consist of brown sandstone belonging to the Upper Silurian series, the surface being elevated above 800 feet above the level of the sea. Descending the mountains to the north, to the limestone valley of Tobercurry, which occurs between them and the Ox mountains, we find the surface with very large boulders of brown sandstone; and continuing to the northward the ascent of the Ox mountains, which are composed of mica-slate, we find the boulders of brown sandstone continued, though diminished in size. On reaching the height of 450 feet above the limestone valley, we meet with limestone Eskers having an east and west direction, crossing the mountain valley at right angles, and on top of which numerous angular blocks of mica-slate rest; but the mica-slate is intermixed with gravel, which is composed altogether of clean rolled masses of Carboniferous limestone. Milan Mountain, one of the Ox range, the summit of which is elevated to the height of 1446 feet above the sea, is composed of granite, forming part of a large protrusion through the mica-slate, which is metamorphosed near the contact.

This granite is large-grained, and is composed of red and white felspar, grey quartz, and black mica, but without any crystals of red felspar such as occur in the Galway granite.

Descending the mountains to the north, we reach the Easky Lough, elevated 706 feet above the sea. Here the granite is bounded by mica-slate, which continues to the base of the declivity, and we find the surface covered by blocks of granite; and continuing still further across the limestone plain to the sea-coast, to Easky village, a distance of 8 miles, we find the surface also covered by very large blocks of granite; and one in particular, which is situated within half a mile of the seashore, and near to Easky village, was, on measurement, found to contain 1360 cubic feet, equal to 100 tons in weight.

Similar granite blocks occur on the surface of the whole line of the north coast of Sligo and Mayo, all of which are similar in composition to the Easky granite, as well as to that which occurs on the summit of the Ox mountains to the west of Easky Lough as far as the town of Foxford; and no doubt can be entertained that such must have been transported by ice.

On the Agency of the Alternate Elevation and Subsidence of the Land in the formation of Boulder-clays and Glaciers, and the Excavation of Valleys and Bays. By the Rev. JOHN GUNN.

Mr. Gunn briefly recapitulated the contents of a paper which he read at the Meeting of the British Association at Liverpool, to the effect that boulder-clays were deposited in a temperate rather than in a glacial period, inasmuch as the area of the sea was increased by the subsidence of the land; the perpetual snowline must have been lowered, masses of ice disengaged, icebergs set floating and the boulder-clays formed; that the glacial epoch was due to the elevation of mountain-ranges and consequent glaciers. He proceeded to show that, in some instances which he specified, the agency of the alternate elevation and depression of the land in scooping out valleys and gorges where there was no evidence of ice action might be traced; that such effects were due to the action of shallow seas, either while clearing off, or while gathering over the surface of the land, and cutting out with its incessant surge water-worn channels and inland bays. He stated, in conclusion, his opinion that there was no occasion to invoke any additional causes of change of climature besides those which were known to exist; but the question which remains to be solved is, to what cause are these alternate oscillations of level due ?

Professor HARKNESS, F.R.S., F.G.S., exhibited one of the earliest forms of Trilobites.