Abstract
LONDON. Geological Society, November 17.—C. J. Stubble-field and O. M. B. Bulman: The Shineton shales of the Wrekin district, with notes on their development in other parts of Shropshire and Herefordshire. In the Wrekin district, the Shineton shales represent almost the whole of the Tremadocian succession, as developed in the Tremadoc district. The subdivision of shales in this main outcrop are:—(6) Arenaceous beds; (5) zone of Shumardia pusilla; (4) Brachiopod beds; (3) zone of Clonograptus tenellus; (2) transition beds; (1) zone of Dictyonema flabelliforme. In the smaller outcrops of the shales lying on the west and south-west, only the lower part of the sequence has been identified. In the Wrekin district a thick mass of shales has been compressed against a north-eastern ridge formed of earlier Cambrian and pre-Cambrian strata, resulting in isoclinal folding with faulting in the north-eastern part of the shale outcrop. In the southwest of the district the shales are less disturbed, except in the immediate neighbourhood of the Church Stretton fault. Six new species of trilobites have been established, of which three belong to new genera; one new brachiopod and three new hyolithids are described.—W. J. Arkell: The Corallian rocks of Oxfordshire, Berkshire, and North Wiltshire. The subdivisions adopted are: (5) upper Calcareous grit; (4) Trigonia-clavellata beds; (3) Osmington Oolite series; (2) Berkshire Oolite series; (1) lower Calcareous grit. It is particularly emphasised that the Coral Rag is a facies deposit which may occur at any date, and that the use of ‘the Coral Rag’ as a stratigraphical term is not permissible. The substitution of the term by Blake and Hudleston's ‘Osmington Oolite Series,’ is suggested. Coral associations started in Yorkshire at the time of the lower Calcareous grit, and migrated southwards during the Corallian epoch, failing to become established in Dorset until the closing phase of the upper Calcareous grit. The chief feature of the Berkshire Oolite series, the Trigonia beds of Berkshire, are contrasted with the much later Trigonia beds of Dorset; whereas the former belong to the Argovian, the latter must be assigned to the Sequanian, the intervening Osmington Oolite series undoubtedly representing the Rauracian.
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Societies and Academies. Nature 118, 934–935 (1926). https://doi.org/10.1038/118934a0
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DOI: https://doi.org/10.1038/118934a0