Page:VCH Warwickshire 1.djvu/42

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A HISTORY OF WARWICKSHIRE white sandstones, coarse, false-bedded, and ferruginous, and containing numerous quartzose pebbles ; the beds resting unconformably on the Cambrian rocks. At Dosthill this unconformity is most marked, the dip of the Cambrian shales being south-west at 20 to 40, while the Coal Measures dip eastwards at angles of 50 to 80. Mr. Fox- Strangways 1 describes the basement sandstone as being well exposed along the lane and in some old quarries on the east side of Monk's Park Wood, south-west of Atherstone ; the sandstone resting nearly horizontally on the Cambrian shales which dip at 38. The workable coals are confined to the lower part of the series ; in descending order the chief seams are the Four-foot ; the Two-yard, Rider, and Bare, worked as one seam ; the Slate ; the Seven-foot ; and the Bench. The lowest seams sometimes rest almost directly on the Cambrian shales, but are locally separated from them by sandstones which vary rapidly in thickness, apparently filling up hollows on the old surface. In the northern part of the coalfield the Four-foot and the Slate coals are separated by over a hundred feet of measures ; but when followed southwards they approach each other by the thinning out of the intermediate beds, so that at the Hawkesbury Colliery south of Bedworth the upper four coals come together to form a single seam which, with thin partings, amounts to about 34 feet in thickness. The principal seams have all been worked along their outcrops. According to Mr. Fox-Strangways the Seven-foot coal is the one now generally mined. At Amington and Glascote the underclay of this seam is used for fire-bricks. Ironstone from the same horizon was formerly raised at Monk's Park and smelted on the spot by means of charcoal ; and Mr. Howell mentions 2 that ironstone was being worked at Bedworth, Hawkesbury, and Wyken. Irregular beds of sandstone are prevalent immediately above the Four-foot coal, and have been quarried here and there between Merevale and Polesworth. About 150 feet below the top of these Coal Measures occurs a well marked band of limestone, from 2 to 3 feet thick ; from the presence of the small coiled annelid shell Spirorbis pusillus it is known as the Spirorbis Limestone. Its outcrop, marked by numerous old work- ings, has been traced with little interruption from Sybil Hill near Kingsbury to Bedworth. It has been seen also in the stream in Monk's Park Wood, south-west of Atherstone, and it appears in its proper position in the outcrop of Coal Measures at Arley. The rock varies in colour from buff or light grey to a dark slaty blue. Besides this band, long since recognized and mapped, Mr. Fox- Strangways 3 has lately obtained evidence of the existence of a second between Baddesley and Baxterley. The Coal Measures generally yield abundant fossil evidence of plant 1 'Geology of Atherstone, etc.' Mem. Geol. Survey (IQOO), p i c 'Warwickshire Coalfield,' ibid. (1859), p. Io ,.

  • 'Geology of Atherstone, etc.' ibid. (1900), p. jo.

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