Page:VCH Lancaster 1.djvu/62

 A HISTORY OF LANCASHIRE St. Hilen's (continued) Higher Roger coal .... .Measures Sir John coal Measures Flaggy Delf .Measures Lower Roger coal (with partings) Measures (with thin coal seam). Rushy Park Coal Measures Little Delf. . Strata, principally shales. Ft. 6 123 3 48 4 78 5 333 4 i6i 3 300 In. 6 o 4 3 8 o 3 Gannister beds 1 800 6 o o o o fVigan (continued) Wigan 9-feet mine (inferior) Measures / Cannel (varying from I ft. 8 in. to 3 ft.) average Measures (varying from O ft. to 15 ft.) 1 King coal Measures Ravin Mine (inferior) .... Measures with 2 ft. coal .... Haigh Yard coal Measures Bone coal Measures Smith coal (Orrell 5 ft.). . . . Measures Arley Mine (Orrell 4 ft.). . . Strata principally shales Ft. In. 9 O 280 o to 15 3 66 3 168 3 150 2 7 3 186 4 300 (?) Gannister beds 1800 to 4 feet. Seams which are thicker are usually The best coals are those averaging from 3 of poorer quality and contain dirt bands. Northwards of St. Helens, a great slice of the Middle Measures is cut out by the great Up- Holland Fault, which has a throw of 700 yards. This fault, like all great faults in the Lancashire area, ranges approximately N.N.W. and S.S.E., and is roughly parallel to the Irwell Valley Fault already mentioned. It brings in the Lower Coal Measures on its eastern side. (D) BURNLEY COAL FIELD This area of Middle Coal Measures is surrounded by the lower series and overlaid by Glacial drifts, no upper series being present. The best section obtainable is that of Fulledge, which, omitting detail, is as follows : — Fulledge Section Strata Doghole Coal. Strata Charley Coal. Strata Kershaw Coal. Strata Coal Strata Burnley 4-feet. Strata Old Yard Coal. Strata Lower Yard Coal. Ft. 14 In.

9 5

10 2

I 6 1 1 Strata. . Ft. 77 In. 8 5 16 Low Bottom Coal Strata / / 3 99 6

I 2 Cannel .... Strata -^3 2 62 5

3 71 Fulledge Thin Bed Coal. Strata ..... 2 10 3 10 Great Mine Coal. Strata 4 116 II 7

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4 25 5 177 China Bed Coal. Strata, with thin Dandy Bed Coal. Strata. . . coal. . 2 . 96 2 q8 2 Arley Mine Coal. . 4 Neglecting thin coals, the section shows about 40 feet of coal lying in a dozen seams. Of these, the Arley Mine is most valuable and has the greatest development, outcropping around the whole Coalfield. One seam, the Californian or Thin Bed, possesses a strong shale roof which is remarkably fossiliferous, no less than 26 species being recorded from it, most of which are fishes. When surveying the Burnley Coalfield prior to 1874, Professor Hull calculated the Arley Mine to have an area of about 23 square miles. Allowing 5,000 tons per acre he estimated the total yield as 73,600,000 tons, of which about one-tenth had been extracted, leaving, after deduction for loss and waste, 65,000,000 tons to be mined in the future.^ The total yield to 1874 of the whole coalfield was estimated at 18,500,000 tons, leaving 89,000,000 tons to be mined.' 1 'Geology of the Burnley Coalfield,' Mem. Geol. Survey (1875), p. 76. ' Op.cit., p. 83. 18