The Geologist/Volume 5/Proceedings of Geological Societies (March 1862)
PROCEEDINGS OF GEOLOGICAL SOCIETIES.
Geological Society of London.—January 22, 1862.—Sir R. I. Murchison, V.P.G.S., in the chair. The following communications were read:—
1. "On some Flint Arrow-heads (?) from near Baggy Point, North Devon." By N. Whitley, Esq., communicated by J. S. Enys, Esq., F.G.S. Immediately beneath the surface-soil above the "raised beaches" of North Devon and Cornwall, the author has observed broken flints; and even at the Scilly Tsles such flints are found. At Croycle Bay, about half-way between Middle-Borough and Baggy Point, at the mouth of a small transverse valley, Mr. Whitley found them in considerable number, collecting about 200 specimens, of which about 10 per cent, of the splintered flints at this place have more or less of an arrow-head form; but they pass by gradations from what appear to be perfect arrow-heads of human manufacture to such rough splinters as are evidently the result of natural causes. Hence the author suggested that great caution should be used in judging what flints have been naturally, and what have been artificially shaped.
2. "On some further Discoveries of Flint Implements in the Gravel near Bedford." By James Wyatt, Esq., F.G.S. Since Mr. Prestwich described the occurrence of flint implements near Bedford ('Geological Society's Journal,' No. 67, p. 366), Mr. Wyatt and others have added seven or eight to the list, from the gravel-pits at Cardington, Harrowden, Biddenham, and Kempston. Mr. J. G. Jeffreys, F.G.S., having examined Mr. Wyatt's further collections of shells from the gravel-pits at Biddenham and Harrowden, has determined seventeen other species besides those noticed by Mr. Prestwich, and among these is Hydrobia marginata (from the Biddenham pit), which has not been found alive in this country. At Kempston, Mr. Wyatt has examined the sand beneath the gravel (which is destitute of shells), and at 3 feet in the sand (19 feet from the surface) he found Helix, Succinea, Bithnia, Pupa, Planorbis, etc., with flint flakes.
3. "On a Hyæna-den at Wookey-Hole, near Wells, Somerset." By W. Boyd Dawkins, Esq., F.G.S. In a ravine at the village of Wookey-Hole, on the southern flanks of the Mendips, and two miles N.W. of Wells, the river Axe flows out of the Wookey-Hole Cave by a canal cut in the rock. In cutting this passage, ten years ago, a cave, filled with ossiferous loam, was exposed, and about 12 feet of its entrance cut away. In 1859 the author and Mr. Williamson began to explore it by digging away the red earth with which the cave was filled, and continued their operations in 1860 and 1861. They penetrated 34 feet into the cave, and here it bifurcates into two branches, one vertical (which was examined as far as practical), and one to the right (left for further research). A lateral branch on the left, not far from the entrance, was also examined. The cave is hollowed out of the Dolomitic Conglomerate, from which have been derived the angular and water-worn stones scattered in the ossiferous cave- earth. Its greatest height is 9 feet, and the width 36 feet; it is contracted in the middle, and narrow towards the bifurcation. Remains of Hyæna spelæa (abundant), Canis Vulpes, C. Lupus, Ursus spelæus, Equus (abundant), Rhinoceros tichorhinus, Rh. leptorhinus (?), Bos primigenius, Megaceros Hibernicus, C. Bucklandi, C. Guettardi, C. Tarandus (?), C. Dama (?), and Elephas primigenius were met with; remains of Felis spelæa were found when the cave was first discovered. The following evidences of man were found by Messrs. Dawkins and Williamson in the red earth of the cave—chipped flints, flint-splinters, a spear-head of flint, chipped and shaped pieces of chert, and two bone arrow-heads; and the author argues that the conditions of the cave and its infilling prove that man was contemporaneous here with the extinct animals in the pre-glacial period (of Phillips), and that the cave was filled with its present contents slowly by the ordinary operations of nature, not by any violent cataclysm.
February 5, 1862.—The following communications were read:—
1. "On some Volcanic Phenomena lately observed at Torre del Greco and Resina." By Signor Luigi Palmieri, Director of the Royal Observatory on Vesuvius. In letters addressed to H.M.'s Consul at Naples, and dated December 17tli, 1831, and January 3rd, 1862.
The author spoke of the evolution of great quantities of carbonic acid gas as seemingly coming from a great subterranean reservoir, and as bubbling up in the sea and killing the fish. He also noticed the outbursts of springs of acidulous, and hot water; and especially mentioned the upheaval of the ground for some miles along the shore at Torre del Greco to the height of more than a mètre above the sea-level.
2. "On the Eecent Eruption of Vesuvius." By M. Pierre de Tchihatcheff. Tchihatcheff's observations were made at Torre del Greco and Naples from December 8th to 25th. Near Torre del Greco several small craters (9–12) have been formed close to each other in an E.N.E.–W.S.W. line, at a distance of about 600 mètres E.S.E. of the crater of 1794; and either on a prolongation of the old fissure, or on one parallel. The phenomena mentioned by Signor Palmieri were described by M. Tchihatcheff in detail, who also alluded to the evolution of sulphuretted hydrogen, and suggested this as an explanation of the flames said to have emanated from the fissures in the ground at various places.
3. "On Isodiametric Lines as means of representing the Distribution of Sedimentary (clay and sandy Strata), as distinguished from Calcareous Strata, with especial reference to the Carboniferous Rocks of Britain." By E. Hull, E.G.S., of the Geological Survey of Great Britain.
The author exhibited maps of the Carboniferous rocks of England and Wales, and by means of coloured isodiametric lines showed the gradual thinning-out of the clays and sandstones in one direction, and that of the limestones in another. Upon these data he urged that the formation of limestone was distinct from the deposition of littoral, or clayey and sandy deposits. The limestones were of organic origin, and formed in the clear deeps of the sea, which those essentially rock-forming creatures the foraminifera, corals, etc., inhabited, but not necessarily formed in deep seas. Thus the condition of the strata beneath us was that of a series of overlapping wedges. The feather-edges of the clays and sands being in one direction, and those of the limestones in the other—the former thinning out from the shore into the sea, the latter proceeding from the bottom of the sea and terminating towards the shore.
Fig. 1.—Primary Section of a Formation.
Thus where the limestones were thickest, as a general rule the sandstones and clays were thinnest; and vice versâ, when there was a great development of clays and sands the limestones were usually thin.
The author made a comparison of argillaceo-arenaceous with calcareous deposits, as to their distribution, both in modern and in ancient seas, and objected to calcareous strata being regarded as sediments, in the strict sense of the word. Noticing the distribution of sediments, in the Caribbean Sea, he referred to the relative distribution of limestones as compared with shales and sandstones in the Oolitic formations (comparing those of Yorkshire with those of Oxfordshire), in the Permian strata of England, and in the Lower Carboniferous strata of Belgium and Westphalia. After some observations on the nature of calcareous deposits, and on the contemporaneity of certain groups of deposits, dependent on the oscillatory movements of land and sea, the author described his plan of showing on maps the relative thicknesses of the two classes of strata under notice, by means of isodiametric or isometric lines (properly isopithic, or indicative of equal thickness of the strata).
Fig. 2.—Distribution of the Calcareous and Sedimeatary Strata of the Great Oolite, Oxfordshire.
Mr. Hull then proceeded to show the application of the isodiametric system of lines to the Carboniferous strata of the midland counties and north of England; showing that there is a south-easterly attenuation of the argillo-arenaceous strata, and a north-westerly attenuation of the calcareous strata. The existence, in the Carboniferous Period, of a barrier of land crossing the British area, immediately to the north of lat. 52°, was insisted upon; and, although this barrier was probably broken through (in South Warwickshire) in the latter portion of that period, yet it divided, in the author's opinion, the coal-area into a north and a south portion, the latter showing a very different set of directions in the attenuation of its strata; the shales and sandstones thinning out eastward and the limestones in the contrary direction.
In conclusion, the author stated his opinion that the source of the Carboniferous sediments was in the ancient North Atlantic Continent, for the existence of which Lyell, Godwin-Austen, and others have argued; and he inferred that the shores of this Atlantis, composed principally of granitoid or metamorphic rocks, were washed on the west side by a current running south-west which drifted the sediment in that direction; and, on the other, by a current running south-east which carried sediment over the submerged British area.
Geologists' Association.—February 3—Professor Tennant, F.G.S., President, in the chair. The following papers were read:—1. "On the Cretaceous Group in Norfolk." By C. B. Rose, Esq., F.G.S. The author, in an elaborate paper, described the general divisions of the chalk formation as exhibited in Norfolk, and following the arrangement proposed by the late Mr. Woodward, he divided the beds into Upper Chalk, Medial Chalk, Hard Chalk, and Chalk Marl. The Upper and Medial Chalk he stated to comprise the chalk with flints (the upper division of other geologists), and the author considers this distinction legitimate, inasmuch as the uppermost bed at Norwich contains organic forms which are not met with in the medial bed. The distinguishing characteristics of the several beds with their peculiar fossils, and the local limits of each formation were fully described, and the paper was illustrated by an elaborate section of the strata of the county.
2. "On the Plasticity and Odour of Clay." By C. Tomlinson, Esq. The author pointed out some of the most remarkable considerations in relation to this subject, such for instance as the fact that clay is only plastic up to a certain temperature; when heated beyond that point (which the author believes, from experiments performed by him, to be somewhere between 600° and 700° Fahr.) it loses its plasticity and acquires the property of rigidity. Moreover, having once lost its plasticity, this quality can never be restored to it by any methods known to science. Further, this property cannot be produced artificially. The constituent elements of pure clay may be combined in the proportions indicated by analysis, but the clay thus produced is not plastic. It is commonly stated that it is the alumina which confers upon clay its plastic property, but the author showed that pure alumina whether gelatinous, or after having been dried and ground up with water, never gives a plastic paste; nor can water be the cause, since melted glass and sealing-wax both possessed the property.
The author considered that the phenomenon may be due to a change in the molecular arrangement of the particles of the clay, and the consequent variation of the attractive force which holds them together,—the particles, under the circumstances under which clay is plastic, being nearer to one another, and the attractive force consequently greater, than under the circumstances when the clay has the property of rigidity.
As to the odour of clay, the author pointed out some difficulties in the way of the common opinion that alumina is the cause of this property, and suggested various considerations which might lead to the elucidation of this point.
Liverpool Geological Society.—January 14.—The papers read were "On the Connection between Physical Geography and Geology." By F. P. Marrat. "On the Geology of the Southern portion of the Isle of Man." By E. B. Franceys.
February 11.—"On Surface-markings on the Sandstone near Liverpool, supposed to have been caused by ice." By G. H. Morton, F.G.S. "A Brief Outline of the Geology of the country about Clitheroe, Pendle Hill, and Bromley." By G. H. Morton, F.G.S.
Manchester Geological Society.—December 31, 1861.—Mr. Binney exhibited a specimen of granite containing petroleum, sent to him by James Yates, Esq., of London. The specimen was obtained in 1818, and is mentioned in Aiken's 'Mineralogy' (1815, p. 60), so that its discovery is of older date than thirty years ago.
The papers read were:—
1. "On the Ventilation of Mines." By Mr. Joseph Goodwin. The author considered that it was not new principles that were required to prevent the loss of life that is taking place year by year in the working of the coal-mines of this country, but attention to the simplest, oldest, and most commonplace precautionary measures. Nor were the evils arising from explosions the only ones to be guarded against; it was alike a duty to pay attention to the sanitary state of the mines and to remove as far as practicable all the causes which are life-destroying, or that injure the health of the operatives. The phenomena of sudden outbursts of gas, and the velocity at which air-currents can be practically passed through the workings of a mine, were the chief topics of the paper.
2. "On the Self-extinguishing and Detector Safety Lamp for working Mines." By Mr. George Charlton, Mining Engineer.
January 28th, 1862.—Joseph Dickinson, Esq., F.G.S., President, in the chair. The following papers were read:—
1. "On the Bank Top and Hagside Pits; and the Proving of Faults." By Andrew Knowles, Esq. The Bank Top Collieries are about one mile from the town of Bury. One shaft or pit adjoins the East Lancashire section of the Lancashire and Yorkshire Railway, and is connected with it by a siding; the other is on the bank of the Manchester, Bolton, and Bury Canal. To the mine, the former pit is 130 yards deep, the latter 160. The mine worked is generally supposed to be identical with the Rushby Park of St. Helens, the Arley of Wigan, and the Royley of Oldham. The Hagside Pit is 760 yards to the deep of the one that adjoins the railway; being 280 yards in depth to the coal, and 300 to the bottom of the sump-hole. There is nothing of particular geological interest in connection with the mine, more than is usually met with in coal-mines. We find Anthracomyæ in a layer, about four inches above the coal; and in the strata between the "two-feet coal" and the main bed, the author had seen several good specimens of Sigillaria. These strata vary from three feet to seven yards in thickness. The average thickness of the mine worked is four feet six inches. In giving his opinion on the proving of faults, the author confined his remarks to the kind commonly met with in the Lancashire coal-field. The faults generally met with in this county are dislocations, whether they are large or small ones; that is, the strata are broken up, and that the coal and other measures are often found the same on each side of the fault-vein. Suppose a fault is met with. It is easily known whether it is a down- or up-throw; if the former, the coal not unfrequently dips a little, for a short distance, before you arrive at it; if the latter, it oftener rises to it. But supposing you arrive, without any previous indication, at a fault, the direction is generally known by the way in which the striæ, or two sides of the fault-vein, commonly called the "slippy partings," point. If a down fault is met with, the direction is away from you, if up, you touch the vein first at the floor of the place where you are driving.
2. "The Ventilation of Mines." Mr. Joseph Goodwin. As the recent catastrophe at the Hartley New Pit has called forth the sympathy of almost every subject within the British realms, and appears at the present time to be exciting the minds of all engaged in the trade, the author thought it was not out of place to consider how far it is safe to trust to a bratticed shaft for ventilating coal-mines. The system of working a colliery with only one shaft presents an unfavourable aspect, viewed from whatever point it may be; but probably the system is more at fault, in so far as it affects the ventilation of a colliery worked upon this principle, and the risk to which it exposes both employer and employed, than if viewed from any other point. The author denounced this system through a thorough conviction that it not only immeasurably increases the risk to both employer and employed, but that, pecuniarily considered, no real advantage occurs from it of working a colliery.