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 GEOLOGY ward until covered and hidden by the next overlying formation. This rule does not apply how^ever to the Pleistocene and recent deposits — the gravels, sands and clays of comparatively modern origin, often termed the ' superficial ' beds in contradistinction to the ' solid ' strata on which they rest ; for, as we shall presently see, these are scattered in patches indis- criminately over the whole district. There is also a slight tilt of the ' solid ' rocks in the opposite direction at the north-eastern corner of the county, by which the beds are bent upwards to the north, so that a shallow trough or ' syncline ' is formed, wherein Eocene deposits are preserved, with higher ground composed of Chalk on both sides. To grasp the full significance of the structural arrangement we must look beyond the limits of the county. It will be found that at a short distance to the southward, in Sussex, the northerly dip of the strata ceases to be perceptible ; and soon a gentle dip to the opposite quarter sets in, which gradually carries down the older rocks beneath the surface and brings in newer formations the farther southward we go ; so that we find the same series of deposits in ascending sequence in a southward traverse across Sussex as in a northward traverse across Kent. The great arch of the strata thus indicated is technically known as the ' Wealden anticline.' In their prolongation westward through Surrey and Sussex into Hampshire the corresponding formations on the opposite sides of this anticline curve in towards each other until they meet, so that the successive belts from the Chalk downwards may be followed continuously from the Kentish coast westward and southward around the central Wealden area and then back eastward to the coast of Sussex, Moreover, although on both sides they disappear eastward beneath the waters of the Channel, they are evidently extended under the sea-floor, for they reappear in the same order on the French coast to the northward and southward of Bas Boulonnais ; after which, when traced still eastward, the opposite belts soon again converge and join. The Wealden anticline is thus rounded off at both ends, and the central area may be pictured as an elongated dome from which the strata dip away all round. This ' dome of elevation ' has been so severely planed down and carved out by the long-continued denudation to be presently described, that its very core is now laid bare in south-western Kent and the adjacent parts of Sussex and Surrey. The position of the county on of the same memoir for details of some Kentish well-sections ; 'The Pliocene Deposits of Great Britain ' by C. Reid (1890), for the ' Lenham Beds ' ; ' The Cretaceous Rocks of Great Britain,' vol. i., by A. J. Jukes Browne (1900), for the Gault and Upper Greensand ; and vol. ii. (1902) by the same author, for the divisions of the Chalk ; also ' Guide to the Geology of London and the Neighbourhood ' by W. Whitaker (ed. 6, 1 901), for a brief account of the north-eastern part of the county. The Memoirs on ' the Weald,' ' the London Basin,' and ' the Pliocene ' contain full bibliographies of the geological literature of these subjects up to the date of their publication ; therefore it has not been deemed necessary to give references to the earlier authorities in the present sketch. References to a few important later papers will be found in subsequent footnotes, but for further information as to the more recent literature the reader should consult the Catalogue of Geological Literature issued annually since 1894 ^7 ^^^ Geological Society of London. The reports of excursions in Kent in Proceeedings of the Geolopits' Association will also be found useful, both for the descriptions of sections and for the references. The county is embraced in the following maps of the Geological Survey, on the scale of one inch = one mile : Sheets (Old Series) i, 3, 4 and 6, with very small portions of Sheets 2 and 5. 5