Abstract
LONDON
Geological Society, December 6.-Mr. J. Prestwich, president, in the chair. Prof. Giovanni Capellini, of Bologna, was elected a Foreign Correspondent of the Society. 1. "On the presence of a raised beach on Portsdown Hill, near Portsmouth, and on the occurrence of a Flint Implement at Downton.“By Mr. Joseph Prestwich, F. R. S., President. The author noticed a section observed by him in a pit ten miles westward of Bourne Common and five miles inland in a lane on the north side of East Cams Wood. It is situated at an elevation of 300 feet above the sea-level, and shows some laminated sands wiih seams of shingle, overlying coarse flint-shingle with a few whole flints, which the author regarded as a westward continuation of the old sea-beach which has been traced from Brighton, past Chichester, to Bourne Common. A flint,.flake was found by the author at the bottom of the superficial soil in this pit. The author also noticed the occurrence of a flint implement of the type of those of St. Acheul in a gravel near Down ton in Hampshire. This gravel capped a small chalk-pit, and its elevation above the River Avon was about 150 feet. Two gravel terraces occur between this pit and the river, one 40 by 60 the other So by 110 feet above the level of the latter. Mr. Codrington stated that, according to the Ordnance Survey, the level of the pit at Cams Wood was not more than 100 feet above the sea, so that it was at about the same level as the gravels of Titchfield and elsewhere. Mr. Evans remarked that the flint flake from Cams Wood presented no characters such as would prove it to be of Palaeolithic age. He was, on the contrary, inclined to regard it as having been derived from the surface. He commented on the height at which the Downton implement had been discovered, which was, however, not so great but that the containing gravels might be of fluviatile origin. Mr. Gwyn Jeffreys thought that if the beds at Cams Wood were marine, some testaceous remains might be found in them. If these were absent, he should rather be inclined to regard them as fluviatile. Mr. J. W. Flower contended that the gravel at Downton could not be of fluviatile origin. He thought, indeed, that the gravel was actually at a higher level than the present source of the river. If this were so, he maintained that "he transport of the gravel by fluviatile action was impossible. Pie further observed that gravels precisely similar, also containing implements, had now been found, as well in the Hampshire area as elsewhere, the transport of which, in his view, could not possibly be attributed to any existing rivers. At Southampton they occur 150 feet above the River Itchen and the sea, and considerably inland; at Bournemouth, on a sea cliff 120 feet in height; and at the Foreland (at the eastern extremity of the Isle ot Wight), on a cliff 82 feet above the sea, and far remote from any river. If, therefore, these deposits were effected by fluviatile agency, it was evident that all traces of the rivers were afterwards effaced by some great geological changes, or, in the alternative, some great geological change, not fluviatile, must have caused the deposit. Upon the whole he was disposed to conclude with the French geologists as well as with many eminent English authors that the accumulation of all these superficial drifts was, as the late Sir Roderick Murchison had said, sudden and tumultuous, not of long continuance; and thus it was such as would result from some kind of diluvial action, rather than from the ordinary long-continued action of water. Mr. Judd pointed out, in contravention to Mr. Jeffreys' views, that in the Fen district, over large tracts of deposits of undoubtedly marine origin, not a trace of marine shells could be found. Mr. Prestwich, while willing to concede that the implement-bearing gravel-beds had beendepoiited unJer more tumultuous action than that due to rivers of the present day, was still forced to attribute the excavation of the existing valleys and the formation of terraces along their slopes to river-action. He showed that Mr. Flower's argument as to the present level of the source of the river was of no weight, as the country in which it had its source was formerly, as now, at a much higher level than the gravel at Downton. As to the absence of marine shells at Cams Wood, he cited a raised beach in Cornwall which, in company with Mr. Jeffreys, he had examined for a mile without finding a trace of a shell, though for the next half-mile they abounded. There was the same d fference between the raised beach at Brighton and at Chichester. He was obliged to Mr. Codrington for his correction as to the level at Cams Wood, though the pit was at a higher elevation than the one to which Mr. Codrington had alluded.-2. “On some undescribed Fossils from the 4 Menevian Group of Wales/ “By Mr. H. Hicks.?n this communication the author gave descriptions of all the fossils hitherto undescribed from the Menevian rocks of Wales. The additions made to the fauna of the Lower Cambrian rocks (Long-mynd and Menevian groups) by the author's researches in Wales during the last few years now number about fifty species, belonging to twenty-two genera, as follows:-Trilobites, 10 genera and 30 species; Bivalved and other Crustaceans, 3 genera and 4 species; Brachiopods, 4 genera and 6 species; Pteropods, 3 genera and 6 species; Sponges, 1 genus and 4 species; Cystideans, 1 genus and 1 species. By adding to these the Annelids, which are plentiful also in these rocks, we get seven great groups represented in this fauna, the earliest known at present in this country. By referring to the Tables published in M. Barrande's excellent new work on Trilobites, it will be seen that this country also has produced a greater variety, or, rather, representatives of a greater number of groups from these early rocks than any other country. The species described included Agnostus, 5 species; Arionelhis, i species; Erinnys, 1 species; Holocephalina, I species; Cono-coryphe, 2 species; Anopolemts, 2 species; Cyrtotheca, I species; Stenotheca, 1 species; T/ieea, 2 species; Protocystites, l species, &c. The author also entered into a consideration of the range of the genera and species in these early rocks, and showed that, with the exception of the Brachiopods, Sponges, and the smaller Crustacea, the range was very limited. A description of the various beds forming the Cambrian rocks of St. David's was also given, and proofs adduced to show that frequent oscillations of the sea-bottom took place at this early period, and that the barrenness of some portions of the strata, and the richness of other parts, were mainly attributable to these frequent changes. Mr. Gwyn Jeffreys suggested that the term Polyzoa might be adopted in preference to that of Bryozoa, as being the more ancient term, and that the name Proserpina should not be applied to the new genus of Trilobites, as it had already been appropriated to a tropical form of land-shell.
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Societies and Academies . Nature 5, 154–156 (1871). https://doi.org/10.1038/005154a0
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DOI: https://doi.org/10.1038/005154a0