Abstract
LONDON
Geological Society, June 19.—John Evans, D.C.L., F.R.S., vice-president, in the chair.—Charles Louis Buxton, Wybrandts G. Olpherts, and William Phelps Richards were elected Fellows of the Society.—The following communications were read:—On the section of Messrs. Meux and Co.'s artesian well in the Tottenham Court Road, with notices of the well at Crossness, and another at Shoreham, Kent; and on the probable range of the lower greensandand palæozoic rocks under London, by Prof. Prestwich, F.R.S., V.P.G.S. The well-known boring at Kentish Town in 1856 showed the absence at that point of lower greensand, the gault being immediately succeeded by hard red and variegated sandstones and clays, the age of which was at first doubtful, but which were finally considered by the author to approach most nearly to the old red sandstone near Frome, and to the Devonian sandstones and marls near Mons, in Belgium. The existence of some doubt as to this identification rendered the boring lately made at Messrs. Meux's brewery particularly interesting, and the method of working adopted by the Diamond-boring Company, by bringing up sharply cut cores from known depths, gave special certainty to the results obtained. The boring passed through 652½ feet of chalk, 28 feet of upper greensand, and 160 feet of gault, at the base of which was a seam 3 or 4 feet thick, of phosphatic nodules and quartzite pebbles. Beneath this was a sandy calcareous stratum of a light ash-colour, passing into a pale or white limestone, and this into a rock of oolitic aspect. Casts and impressions of shells found in this bed showed it to be the lower greeusand, whose place it occupied. The boring was carried further in the hope of reaching the loose water-bearing sands of this formation, but the rock became very argillaceous, and, when 62 feet of it had been passed through, the boring entered into mottled red, purple, and greenish shales, dipping at 35° in an unascertained direction. These beds continued through a depth of 80 feet, when, their nature being clearly ascertained, the boring was stopped. The fossils of these coloured beds, which included Spirifera disjuncta, Rhynchonella cuboides, and species of Edmondia, Chonetes, and Orthis, show them to be of Devonian age. Thus, the existence of paleozoic rocks at an accessible depth under London and the absence of the Jurassic series, as maintained long since by Mr. Godwin-Austen, is experimentally demonstrated. These facts are of interest in connection with the question of the possible extension of the coal-measures under the cretaceous and tertiary strata of the south-east of England. The beds found at the bottom of Messrs. Meux's boring are of the same character as the Devonian strata which everywhere accompany the coal-measures in Belgium and the north of France, being brought into juxtaposition with them by great faults and flexures. The author refers especially to a remarkable section at Auchy-au-Bois, in the western extremity of the Valenciennes coal-field, which is particularly interesting from its furnishing evidence that the Hardinghen coal-field, between Calais and Boulogne, is a prolongation of that of Valenciennes, and because the same strike and a prolongation of the same great fault observed at Auchy-au-Bois through Hardinghen would carry the southern boundary of any coal-field an the south-east of England just south of Maidstone, thence passing a little north of London. Hence it is in the district north of London that there is most probability of the discovery of the carboniferous strata. The extent of country in which shafts could be sunk to the palæozoic strata will, however, be limited by the presence of the water-bearing lower greensand, which probably reaches close to London in the south, reappears in Buckinghamshire and Bedfordshire, thirty or forty miles north of London, and probably extends some distance towards the city under the chalk hills of those counties and Hertfordshire. The nature of the representative of the lower greensand in the boring, and the characters of the fossils contained in it, lead the author to the conclusion that in it we have a deposit produced near the shore of the neocomian sea, here probably consisting of cliffs of Devonian (or carboniferous) rock. From these cliffs the calcareous material which here replaces the usual loose sands of the lower greensand was perhaps derived by the agency of springs; and the shore-line itself must be situated between the south end of Tottenham Court Road and the Kentish Town boring. The sandy beds of the lower greensand will probably be found to set in at no great distance to the southward, presenting the conditions necessary for storing and transmitting underground waters. A test boring made by Mr. H. Bingham Mildrnay at Shoreham Place, about five miles from oSevenoaks, and in which the lower greensand was met with at about the estimated depth (450 feet) and furnished a supply of water, seems to confirm these views.—Notes on the palæontology and some of the physical conditions of the Meux's-well odeposits, by Charles Moore, F.G.S. The chief interest of Mr. Moore's investigations centres in the sixty-seven feet of strata intervening between the gault and Devonian. In this marly and. oolitic-looking deposit he found no less than eighty-five odifferent kinds of organisms, exhibiting a singular admixture of marine and lacustrine forms of life. Forarninifera are rare, but entomostraca and polyzoa are very abundant. Some genera are found, such as Carfenieria, Saccammina, Thecidium, and Zettania, of which the range in time is greatly extended by these investigations. The author fully confirms Mr. Etheridge's reference of the beds in question to the neocomian period, widely as they differ in physical characters from the lower greensand strata of the south-east of England. From a careful study of the nature and condition of preservation of the minute organisms, he concludes that the deposits which contain them were formed at first in shallow lacustrine hollows on the surface of the Devonian rocks now lying buried at a depth of 1,000 feet below London, and that these lakes were invaded by the waters of the neocomian sea, with the deposits of which their sediments were in part mingled, and under which they were finally buried.—The chair was then taken by Prof. Prestwich, M.A., F.R.S., vice-president.—On Pelanechinus, a new genus of sea-urchin from the coral rag, by W. Keeping, F.G.S., Professor of Geology in the University College of Wales.—Remarks on Saurocephalus, and on the species which have been referred to that genus, by E. Tulley Newton, F.G.S., of H.M. Geological Survey.—A microscopical study of some Huronian clay-slates, by Dr. Arthur Wichmann.—On a section through Glazebrook Moss, Lancashire, by T. Mellard Reade, F.G.S.—On the tertiary deposits on the Solimoes and Javary Rivers in Brazil, by C. B. Brown. With an appendix by R. Etheridge, F.R.S., and communicated by him.—On the physical history of the English lake-district, with notes on the possible subdivision of the Skid-daw slates, by J. Clifton Ward, Assoc. R.S.M., F.G.S.—On some well-defined life-zones in the lower part of the Silurian (Sedgw.) of the Lake-district, by J. E. Marr. Communicated by Prof. T. M'K. Hughes, F.G.S.—On the upper part o of the Bala beds and base of Silurian in North Wales, by F. Ruddy. Communicated by Prof. T. M'K. Hughes, F.G.S.
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SOCIETIES AND ACADEMIES . Nature 18, 350–352 (1878). https://doi.org/10.1038/018350c0
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DOI: https://doi.org/10.1038/018350c0