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 A HISTORY OF KENT As regards the history of these coal explorations it will suffice to give references to the already extensive literature of the subject, and to note that so long ago as the year 1856 the opinion that Coal Measures might occur within a workable depth in Kent was clearly stated.^ It was not until 1890 however that this opinion was verified by a deep boring on the site of the Channel Tunnel Works at the base of Shakspere Cliff near Dover/ which reached the Coal Measures at a depth of 1,157 ^^^^ below the surface and passed through ten' coal seams at various depths between 1,180 and 2,221 feet, of thicknesses varying from I foot to 4 feet and giving an aggregate thickness of 22 feet of coal. This discovery led to the sinking of shafts on the same site, and to the commencement of several other borings in different parts of the interior of the county for the purpose of testing the lateral extension of the Coal Measures, the work being carried on entirely by private enterprise. Owing to engineering difficulties and other causes however, in spite of the expenditure of very large sums of money the Dover shafts have not at the time of writing, reached the coal seams ; and only one of the other borings — that at Ropersole, 8 miles north-west of Dover — is known to have entered Carboniferous rocks, while another — at Brabourne, 5 miles east of Ashford — has shown that the Coal Measures do not extend to that place. Sooner or later the deep-seated Coal Measures of Kent will no doubt become of economic importance, and the pre- sent aspect of the north-eastern part of the county thereby greatly altered. For the nearest places where the Jurassic and older rocks proved in these borings may be seen at the surface, we have to look eastward across the Channel to France, or westward to Somerset and the adjacent western counties. The intermediate sections now obtained in Kent are certain to prove of high scientific value in elucidating the deep- seated geology of the whole of the south-east of England. The following are the records of the Kentish borings which have been published up to the present time : — > R. A. C. Godwin-Austen, ' On the Probable Extension of the Coal Measures beneath the South- eastern part of England,' Quart. Joum. Geol. Soc. (1856), xii. 38. This author's opinion was fully discussed and acquiesced in by Prof. J. Prestwich in ' Report on the Probabilities of finding Coal in the South of England,' Reports of the Coal Commission (1871), i. 146. The hypothesis was sub- sequently discussed by many other geologists. For critical review of this literature up to the year 1 888 consult W. Wliitaker, M^ot. Geol. Survey, 'The Geology of London ' (1889), vol. i. chap. 2, 'Underground Plain of Older Rocks,' pp. 10-49 ! ^"'^ ''^ 'Joum. Soc. Arts (1890), xxxviii. 543. 2 Prof W. Boyd Dawkins, under whose advice the boring was made, has published several papers on the history of this exploration and on the results attained : see Trans. Manchester Geol. Soc. (1890), XX. 502 ; (1892) xxi. 456 ; (1894) xxii. 488 ; ibid. 'History of the Discovery' (1897), xxv. 155 ; Reports British Assoc: Cardiff (1891), 637; Oxford (1894), p. 648; Dover (1899), p. 734; Contemporary Revietv, April, 1890 ; ColRery Guardian, June, 1894, etc. Also for detailed sections of Dover boring, see W. Boyd Dawkins in third paper above cited ; and joint paper by F. Brady, G. P. Simpson and N. R. Griffith, 'The Kent Coalfield,' Trans. Fed. Inst. Mining Eng. (1895-6), xi. 540 ; and for later general discussion of the subject, R. Etheridge, ' On the Relation between the Dover and Franco-Belgian Coal Basins,' Rep. British. Assoc. Dover (1899), p. 730. » Or twelve seams ; see Prof. W. B. Dawkins, Rep. British Assoc. Dover (1899), p. 736.