. The Quarterly journal of the Geological Society of London. a^ 3 extendinto the Basement-bed of the London Clay, and 2 to the levelof the Woolwich group, whilst as many as 11, or nearly one half ofthe whole, are peculiar to the Thanet Sands. The distinction is not tobe attributed to different conditions of the waters, for although atWoolwich this has necessarily operated by excluding the more marinespecies and introducing in their place others of fluviatile and sestuarineorigin, still in, and adjoining, the Isle of Thanet, both the middle andupper divisions of the Lower London Tertiaries are
. The Quarterly journal of the Geological Society of London. a^ 3 extendinto the Basement-bed of the London Clay, and 2 to the levelof the Woolwich group, whilst as many as 11, or nearly one half ofthe whole, are peculiar to the Thanet Sands. The distinction is not tobe attributed to different conditions of the waters, for although atWoolwich this has necessarily operated by excluding the more marinespecies and introducing in their place others of fluviatile and sestuarineorigin, still in, and adjoining, the Isle of Thanet, both the middle andupper divisions of the Lower London Tertiaries are marine, and con-sequently the conditions in this respect of the three groups are equal,and still the difference of fauna holds good. Annexed are the detailed sections of the two localities where the Thanet Sandsare most fossiUferous (the Reculvers excepted). Their relation to the other partsof the Lower London Tertiaries is shown in sections 1, 2, & 3, PI. XV. Fig. 4.—Section of part of the Cliff at Pegwell Bay, nearRamsgate. {s in Section 1, PL XV.). cdci Feet. 1. Drift of light-coloured brick-earth, with a thin irregular seam of gravel (angular and small round flints), mixed with broken fragments of theshells of the underlying beds, at its base 4-6 2. Light yellow slightly clayey sand with shells in layers and patches; * a, tabular masses of fissile micaceous calcareous sandstone, with fewshells,—a very small Corhula often occurs in great abundance; bsmall calcareous concretions, in which the Pholadomya Koninckii is notuncommon; c, large concretionary blocks, often very argillaceous;their lower surface frequently presents masses of shells, especially theCyprina Morrisii. Traces of Plants occur both in ** b and c. 16 3. Grey clayey sands, rather dark when wet, but lighter-coloured when diy (the upper part especially looking at a distance almost like chalk),—thelower part is more argillaceous and darker; d* a seam of grey claywith shells in patches; * e, a thin layer of i
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
