origin is directly opposed to such a hypothesis. Still the object of the author is not to dispute the existence of a glacial period in his district, but simply to state his opinion that the conditions which the drifts exhibit must be ascribed to the effect of moving water, and not of ice.

He alludes to Agassiz, as the first who applied the ice theory to the drift phenomena of the British Islands, and remarks, that it may be with the geologist as with the painter or the musician, in whose works, though they speak the universal language of genius, a national accent may still be noticed; and the ice or water theories may, to a great extent, owe their origin to the physical circumstances of the native countries of their proposers. An inhabitant of Switzerland, who has been accustomed to observe the vast powers of the glaciers grinding away the sides of mountains, scooping out their bed in the granite rock, and carrying the fragments of fallen peaks on the crests of their solid waves, must see that ice is indeed a great agent in geological phenomena; and, on the other hand, to a native of our western isles, who has been viewing the Atlantic from his childhood, and has seen cliff's pulled down, and the huge masses of their debris tossed about by the surge, the force of water will be considered unsurpassed. One as correctly as the other might found a theory of limited applicability on the great power he had been used to contemplate, but they would be equally wrong in giving it too great a generalization; and the author hopes that, in his own opinions, he has not been unduly influenced by local associations.

He thinks that the general contour of the country shows the existence of great denuding action from the east at a period anterior to the drifts; and the rise of outcropping strata is generally towards the lowlands, proving them to be valleys of denudation, where the upheaval and disturbance of the limestone beds rendered them liable to be carried away. Looking south from Galway Bay, a grand illustration of this phenomenon may be seen, where the inclined beach terraces of ancient seas ascend the Burren Hills like stairs of giants; but the remark does not apply to the mountains west of Loch Mask and Loch Corrib.

On certain Alterations of Level on the Sea Coast of part of the County of Waterford, and the cause thereof. By Dr. CLARke.

The author described the elevation of an ancient sea-beach on the coast of the County of Waterford, extending about two and a quarter miles, and reaching at one part an elevation of 60 feet. The shells found in the upraised beach were exclusively those of Cardium edule; the elevation is believed by the author to be of later date than any of the other pleistocene deposits of Ireland. The circumstances attending the formation of trap-rock at Newton Head were noticed as bearing on this phenomenon, the elevation of the beach being apparently dependent on and due to the igneous agency which raised the dyke.

On the Geology of the Neighbourhood of Tralee.

By F. J. FOOT, Geological Survey.

This paper is descriptive of a section north and south, from Bird Island on the south shore of the mouth of the Shannon to the village of Castlemaine.

The rocks seen in this section are given in a descending series, the uppermost being the coal-measure shales, consisting of thick beds of black shale, more or less fossiliferous, alternating with beds of olive-coloured grits, containing fragments of plants.

The rocks under these are those of the carboniferous limestone, which may be divided into three parts, upper, middle, and lower.

The upper limestone in this district varies from a light grey compact to a dark grey crystalline limestone, abounding in fossils.

The middle portion is a thin bed, only a few feet thick, being a shaly impure limestone, representing the calp.

The lower member is chiefly a light gray hard compact rock, abounding in fossils. The thickness of the limestone is very difficult to ascertain, partly because the limestone is often very thick-bedded, and partly that the great amount of drift in the

1857.

5

district prevents one getting a good section. The lines of stratification are also often much effaced by joints, cleavage, and weathering of the surface. Under the limestone comes the carboniferous slate, consisting of black shale, brown grits, and soine calcareous bands, full of fossils, the thickness being about 500 feet. Next comes the yellow sandstone of Dr. Griffith, consisting of yellowish grit and shales, varying from 500 to 1000 feet in thickness. The former is the thickness at the Slieve-Mish mountains near Tralee; the latter that near Bird Island. Here I discovered a thin bed full of plants, all branching and some having a cellular structure; there are some leaves that look like those of Cyclopteris Hibernica.

Below the yellow sandstone comes a considerable thickness of red sandstones and slates, amounting at Slieve-mish to about 800 feet; from this they pass downward into a conglomerate. A remarkable point about this conglomerate is the manner in which it varies both in thickness and character. Its thickness where it is shown on the line of section, is about 80 feet, and it consists of large and small rounded pebbles of quartz, jasper, and hornstone, in a base of red sand; while about one mile and a half further west (on the south side of the anticlinal of the Slieve-mish range, where the beds are thrown down by a fault), it is more than 200 feet thick, and consists of large angular fragments of gneiss, mica-schist, grey grit, trap ashes, &c., thinning out on the northern slope to about 50 feet.

This conglomerate is the lowest rock seen in this section, but it must not be confounded with that which is now considered as the base of the carboniferous rocks in this district, and which is several hundred feet below it, and lies unconformably on the Silurians.

On the Relations of the Rocks at or below the base of the Carboniferous Series of Ireland. By Sir RICHARD GRIFFITH, Bart., LL.D., M.R.I.A., F.G.S. The author stated that he had found great difficulty, when preparing the several editions of his Geological map of Ireland, in deciding on the class to which certain rocks characterized by brown and reddish-brown grits and conglomerates ought to be assigned.

These rocks occur in three districts in the north; viz. one in the neighbourhood of Pomeroy and Omagh, in the counties of Fermanagh and Tyrone, one forming the Curlew mountains in Sligo and Mayo, one forming the Croaghmoyle mountains and neighbourhood in Mayo, and one extensive district in the south occupying large portions of the counties of Cork and Kerry.

The author then referred to his paper read at the Cork meeting of the British Association for the Advancement of Science, from which it appeared that he was then inclined to connect the conformable brownish-red sandstones and conglomerates with the Silurian system.

The author next referred to his paper read to the Belfast meeting of the Association on the yellow sandstone of the north shore of Mayo, and to the advice tendered to him by Sir H. De la Beche and Mr. Jukes, with reference to the omission on his map of the so-called Old Red Sandstone district, as the red rocks appeared to them to be all carboniferous, an opinion confirmed by the subsequent discovery of Sigillaria and Stigmaria ficoides within the area, as also in similar rocks at MacSwyne's Bay in Donegal, a very large specimen from which locality is preserved in the court-yard of the Royal Dublin Society.

It appears therefore that these supposed Old Red Sandstone rocks of the North are undoubtedly carboniferous; but it is yet doubtful to what series the red rocks below lying unconformably to them may belong.

The author then mentioned the limits of the true Old Red Sandstone of the South, from the cast to the west side of the island, reposing on other red and purple rocks, which in the Dingle district become distinctly unconformable to them, while the red and purple rocks themselves repose conformably on fossiliferous Silurian rocks.

He then described the grounds on which he based his division of yellow sandstone, principally from the occurrence of plants subsequently found by Professor Haughton, Mr. Jukes and others, to extend still lower down into the red rocks; and stated, that as he considered the plants to be the proof of the yellow sandstone being of carboniferous age, he was not prepared to deny the inference that the whole of the fish-beds of

Scotland, and the similar rocks of Glamorganshire and South Wales, might belong to the carboniferous system.

He estimated the mean thickness of the true Oid Red Sandstone of the South of Ireland at about 3000 feet, including 800 feet of yellow sandstone.

The author then described an east and west section across Ireland from Blackstairs mountain in the county of Wexford to the extremity of the Dingle promontory in the county of Kerry, and afterwards entered into some details as to the structure of the Dingle district and that round Killarney and Glengariff. He referred more particularly to the great difficulty which arose from the fact that the red and green rocks (for which Mr. Jukes had proposed the term 'Glengariff grits,' a term which had his entire concurrence) were conformable to the Silurian rocks of the Dingle district, while the Old Red Sandstone reposed unconformably on both; on the other hand, in the country south of Dingle Bay, it should be mentioned these same Glengariff grits passed insensibly up into the Old Red Sandstone; and no want of conformity could be found in any part of the series, from the Glengariff grits as far up as the coal-measures; and the author exhibited a north and south section through the Dingle promontory to the valley of Kenmare, illustrative of his views. He then pointed out the analogy between the Glengariff grits and the brownish-red grits of the three districts in the north of Ireland already alluded to, referring to numerous sections which he had formerly prepared.

The author thought, on the whole, from the occurrence of similar felstones and ashes in the Silurian rocks and the Glengariff grits, and the facts stated above, that there was a double probability in favour of those rocks being of Silurian rather than of Devonian age, or at all events that he was justified in the classification which he had made on his map, and in distinguishing these rocks by separate letters and colours.

Notes from the Barbary Coast, with Fossils.

By G. F. HABERSHON. (Communicated by Dr. GLADSTONE.)

In this communication there were described the promontory of sandstone stretching into the Atlantic, on which the town of Mogador is built; two islands, likewise of sandstone, one of which contains a remarkable central depression; the sand-hills, and the barren sandy plain, which extends some 20 miles by 5 or 6 inland; and the Ihebel-Hadeed, or "Mountains of the Iron," a day's journey to the north of Mogador. There is a universal tradition that the plain was once luxuriant with vegetation, but had been gradually covered with sand. This could not have been blown from any desert, as the plain is surrounded on all sides by fertile regions, except that open to That the land is sinking, is rendered probable by the very low position of the town of Mogador, of a palace built long since by one of the emperors of Morocco, and of a circular fort erected by the Portuguese on the shore and now in ruins, and especially by the fact that it was the custom of the Moors in former times to drive their cattle to feed on the larger island, by a path which is now covered at low tide by about 10 feet of water.

the sea.

About half a mile from the northern gate of Mogador is a sand-hill, in which Mr. Habershon had seen what appeared the stems, branches, and twigs of many trees, but all converted into sand and hollow. Dr. Gladstone, who had suggested the propriety of bringing over some of these fossils, described the specimens accompanying the paper as branching irregular tubes of carbonate of lime, on the outside of which sea-sand of a very heterogeneous character was cemented by crystals of the carbonate. These specimens varied from half an inch to five inches in diameter; and though he had formed several theories as to their origin and nature, not one of these seemed to meet every point of the case. The communication was further illustrated by specimens of sandstone from Mogador and the islands, minerals from the province of Soos, and ironstone and chert from the Iheb-el Hadeed.

On the Geology of Caldbeck Fells, and the Lower Sedimentary Rocks of Cumberland. By Professor HARKNESS, F.R.S.

The district alluded to in this communication forms the northern portion of the mountainous area of the lake district of Cumberland. Caldbeck Fells, including their

eastern extremity Carrick Fell, consist of masses of plutonic and igneous rocks. On the southern slopes of these hills there is seen Skiddaw slate, which generally has a south dip; and this Skiddaw slate, as it approximates the granite of Skiddaw Forest, passes into chiastolite slate, chiastolite rock, and a pseudo-gneiss. On the south side of the granite area the same phenomena occur, but on this side hornblende rock and actinolite rock also appear. In the metamorphic rocks, and likewise in the ordinary Skiddaw slates which succeed them in position, the strike of the strata is nearly east and west, and the general arrangement of the strata seems to indicate that the plutonic and igneous masses of Caldbeck Fells form the axis of the group rather than the granite of Skiddaw Forest. With respect to the unaltered rocks of the Skiddaw district, these have been referred by Prof. Sedgwick to three groups, black Skiddaw slate, grits seen in the masses of Grassmoor, and grey Skiddaw slate containing fossils described in the Palæozoic fossils of the Woodwardian Museum. The upper grey slates are the deposits which have hitherto afforded organic remains. Last year the author obtained traces of worms from the black Skiddaw slate, the lowest member of the unaltered series, at Threlkeld, and, from a communication which the author had recently from Prof. Sedgwick, it would appear that in these low strata graptolites have been lately obtained by Mr. J. Ruthven. With regard to the lithological nature of these Skiddaw rocks, it would seem that there is a considerable change according to locality. Westward grey slates, with intercalated grits, obtain on the line of the strike of the black Skiddaw slates, leading to the inference that coarser beds supply the place of the finer black slates on the eastern margin of the area.

On the Jointing and Dolomitization of the Lower Carboniferous Limestone in the Neighbourhood of Cork. By Professor HARKNESS, F.R.S. The district round Cork consists of a series of hills and valleys, the former composed of Devonian, and the latter of limestone belonging to the lower portion of the carboniferous series. In the latter are joints having three directions: one, the prevailing direction being north and south; and of the other two, one is almost horizontal and the other oblique. These joints occur in great profusion in most of the limestone localities; but in certain spots where the limestone is siliceous and bedded, the jointings are imperfect and the stratification distinct. Among these limestones there are seen in the neighbourhood of Cork dykes of dolomite, and these dykes in jointed limestone conform to the main perpendicular joints. In the limestone, where the stratification is distinct, we often find also dolomites; and these agree with the planes of stratification. The production of these dolomites appears to be subsequent to the deposition of the strata in which they occur. From the observations of Regnault it would seem that sea-water (containing sulphate of magnesia) is capable of exerting considerable influence on limestone, giving rise to carbonate of magnesia and sulphate of lime; and the phenomena exhibited by the district around Cork would lead to the inference that sea-water, finding access into rocks by joints, and in some instances along the planes of stratification, so produced the dolomitic masses.

On the Records of a Triassic Shore. By Professor HARKNESS, F.R.S. The area occupied by the trias strata referred to occurs in the north-west of England and the south of Scotland. The deposits which form this series consist of argillaceous strata and sandstones, and these beds have their surfaces marked by ripples, which have resulted from the action of the wind on shallow water. Ripples of another character also occur, and these have been produced by the influence of small rills traversing a muddy shore. Tracks which have originated from the wanderings of crustaceans likewise make their appearance on the surface of the sandstones, and with these are found associated the sinuous tracks of annelids, as well as the pitted hollows which form the entrances into the burrows of these animals. Pseudomorphic crystals of salt are also exhibited in the state of small pyramidal elevations on the under sides of the sandstones, affording evidence of natural salt-pans on this Triassic shore. Small pittings mark, in many instances, the faces of the sandstones, and the surfaces reposing upon these pitted faces manifest little dome-like elevations. These have arisen from the effect of rain-drops, in most instances of a small size, resulting from fine

rain; in some instances, however, oblong impressions make their appearance, and they are the results of heavy drifting rain. All the physical conditions on these ancient shores are such as we find under favourable circumstances on the sandy and muddy coast of our present seas.

On a Model illustrative of Slaty Cleavage.

By the Rev. Professor HAUGHTON, M.A., M.R.I.A.

This model was intended to illustrate Mr. Haughton's views respecting the distor tion of fossils by cleavage. It was made of zinc, and represented one-eighth part of the ellipsoid of compression. A moveable zinc quadrant might be placed in different positions in the model, and thus show the manner in which the line of greatest elongation of the fossils shifted with the intersection of cleavage and bedding.

Mr. Haughton stated that in all the rocks he had hitherto examined, the ellipsoid of compression was very nearly oblate, with its short axis perpendicular to the planes of cleavage.

On Fossil Stems allied to Stigmaria, recently obtained from the Upper Beds of the Old Red Sundstone of Hook Point, Co. Wexford. By the Rev. Professor HAUGHTON, M.A., M.R.I.A.

It is well known to geologists that many plants of the genera Stigmaria, Lepidodendron, Knorria, Sigillaria, &c., have recently been found on this geological horizon in Donegal, Mayo, Kilkenny, Cork, and Wexford.

The specimens found at Hook Point are generally in very bad preservation. Those exhibited by Professor Haughton showed the structure of the stem well-preserved. There must have been a central bundle of vascular tissue, more or less woody; a hollow stem, and a thick bark; the latter being connected with the central vascular column by oblique spinous bundles analogous to the medullary rays of Calamites.

In the specimens exhibited by Prof. Haughton, the central vascular column was represented by a hollow tube filled with coaly matter and surrounded by the sandstone cast of the hollow stem, outside of which again appeared the carbonaceous remains of the bark of the stem, with the spinous processes on its inner surface. On the whole he considered these obscure remains of the earliest vegetation of Ireland to be allied to Stigmaria more closely than to any other fossil genus, and he believed that there were some peculiarities in these plants which would amply repay a careful study. Accompanying the plant beds at Hook, was a thin bed of anthracitic coal, about 2 inches thick, the stems being found in the soft sandstone beds both above and below the coal seam. The stems were sometimes 2 feet long, and always terminated abruptly in the rock.

In conclusion, Prof. Haughton stated that geologists present at the Meeting would be able to form an excellent idea of the yellow sandstone flora by visiting the Museum of the Geological Survey, Royal Dublin Society, and Trinity College, all of which contained fine specimens of these plant remains.

On the Existence of Forces capable of changing the Sea-level during different Geological Epochs. By Professor HENNESSY, M.R.I.A.

If, in assuming its present state from an anterior condition of entire fluidity, the matter composing the crust of the earth underwent no change of volume, the direction of gravity at the earth's surface would remain unaltered, and consequently the general. figure of the liquid coating of our planet. If, on the contrary, as we have reason to believe, a diminution of volume should accompany the change of state of the materials of the earth from fluidity to solidity, the mean depth of the ocean would undergo gradual, though small alterations, over its entire extent at successive geological epochs. This result is easily deduced from the general views contained in other writings of the author, whence it appears, that if the surface stratum of the internal fluid nucleus of the earth should contract when passing to the solid state, a tendency would exist to increase the ellipticity of the liquid covering of the outer surface of the crust. A very small change of ellipticity would suffice to lay bare or submerge extensive tracts of the globe. If, for example, the mean ellipticity of the ocean increased from to , the level of the sea would be raised at the equator by about 228 feet, while under