Page:VCH Lancaster 1.djvu/60

 A HISTORY OF LANCASHIRE The chief coal seams of the Oldham area' are about ten in number. The most valuable and the one which has been most worked is the Black Mine, averaging four feet in thickness. Another seam of considerable importance is the 'New Mine' of the Ashton-under-Lyne district, which lies below the Black Mine, and about 1 00 yards above the Royley or Arley seam. It may be equivalent to the Neddy Mine of Oldham, or one of the thin seams below it. The Lower Bent Mine or Peacock coal is of good quality and much used. The ' Great Mine ' of Oldham yields over 8 feet of coal, but at Ashton-under-Lyne it includes dirt bands. Higher in the series than any given in Professor Hull's list are the Great and Roger Mines of Ashton-under-Lyne and Dukinfield. The former is 6 feet thick, the latter 4 feet, and the interval is but 32 yards. Still higher in the series, and at some 400 to 500 yards above the Great Mine, is the Yard Mine of Moston, which is supposed to represent the Bradford Four-Feet. Nowhere in this area is the whole of the Middle series present from summit to base, unless it be to the south of Dukinfield and at Moston. Between the Great and Yard Mines at Dukinfield is a coal seam about eighteen inches in thickness, the shale roof being rich in fossils, and containing ironstone balls very similar to those over the Upper Foot of the Lower Coal Measures. This horizon is exposed in the banks of the river Tame, near the bend west of Dunkirk Colliery, and was also cut through in sinking the shaft of the Ashton Moss colliery. The remarkable feature of this horizon is that it has yielded Goniatites, Pterinopecten, &c. The late J. W. Salter regarded the fauna of this horizon as comparable to that of the Lower Coal Measures of Shropshire, and as markedly different from that of the Lancashire Lower Coal Measures. This can now hardly be said to be correct, as the observations of the writer have shown that the ' Marine Band,' as it is often called, has yielded several species of fossils characteristic of the latter. The fauna of the Marine Band most closely approximates that of the Upper Foot or Bullion and Mountain Four-Feet Mines, and the differences are probably those naturally due to a later development. (B) BOLTON AND BURY AREA In this area the Middle Coal Measures reach fully a thousand yards in thickness, and scarcely any portion remains untouched, mining being particularly active. The best generalised section of it is that of Professor Hull, curtailed from a much more detailed section published by J. Dickinson, Esq., late Chief Inspector of Mines. Generalised Section between Manchester and Bolton Ft. In. Ft. In. Worsley Four Feet Coal .... 43 Five Quarters Coal 36 Strata 782 o Strata 266 o Bin Coal 36 Trencherbone Coal 5 O Strata 78 o Strata 102 O Albert Mine 33 Cannel Mine (Cannei only 6 inches). 4 6 Strata 42 o Strata 58 O Crumbourke Coal 40 Saplin Coal 40 ^"'='^: 144 O Strata 107 o Rams Alme 56 Plodder Coal -, q Strata 254 7 Strata ' 114 O White Coal 30 Yard Mine .... Z q Strata 2i o Strata ' 168 o 2 o 206 o Black Coal 30 Three Quarters Mine Strata 45 o Strata Old Doe Coal 8 Arley Mine . Strata 310 (Slightly modified fi-om Hull's Coalfields of Great Britain, 1881, pp. 202, 203.) Fourteen seams are worked, yielding nominally about sixty feet of coal, but from this must be deducted the thickness of shale partings, bass, and dirt bands, which frequently occur. The lowest bed of the series IS the Arley Mine. 1 It must not be forgotten that the Oldham Middle Coal Measures are flanked to the north and east bv ground in which coals of the Lower Series are extensively mined. ^ 16