COAL 



833 



Through this hill canals have been cut, for working the immense beds of carboniferous 

 limestone. These occur in the lower series of the strata of the coal-field, and therefore 

 at a distance of many miles from the Castle-hill, beyond the outcrop of all the workable 



480 



a. Alluvial cover. 



b. Bed of trap or greenstone. 



c. Alternating coal strata. 



d. Coal-seams. 



e.. Position of greenstone, not ascertained. ; 

 /. Strata in which no coals have been found. 

 g. The overlapped coal. 

 h. The double coal. 



483 



coals in the proper basin-shaped part of the field ; but by this apparently inverted 



basin-form, these limestone beds are elevated far above the level of the general surface 



of the country, and consequently above the level of all the coals. We must regard 



this seeming inversion as resulting from 



the approximation of two coal-basins, 481 



separated by the basset edges of their 



mountain limestone repository. 



Fig. 483 is a vertical section of the 

 Dudley coal-basin, the upper coal-bed 

 of which has the astonishing thickness 

 of 30 feet; and this mass extends 7 

 miles in length, and 4 in breadth. 

 Coal-seams 5 or 6 feet thick are called 

 thin in that district. 



For a satisfactory description of the 

 coal-field of South Staffordshire, the 

 reader is referred to a memoir, ' On the 

 Geology of the South Staffordshire Coal- 

 field,' by J. Beete Jukes, published in 

 the ' Records of the School of 

 Mines.' 



It is not possible in the 

 present work to enter into 

 any further description of 

 the coal-fields of this country. 

 In the selections which have 

 been made, striking types 

 have been chosen, which are 

 sufficiently characteristic to 

 serve the purposes of general 

 illustration. There are many 

 variations from the condi- 

 tions which have been de- 

 scribed, but these are due 

 to disturbances which have 

 taken place either since the 

 formation of the coal, or 

 during the period of the 

 actual deposition of the coal. 



The probability of finding coal in the South of 'England has, of late, been invested 

 with especial interest ; and we are from time to time startled with the announcement 

 that coal has been discovered. 



Not long since a paragraph appeared announcing a remarkable discovery of coal in 

 the Isle of Wight. The late gales had denuded the shore of Whitecliff Bay of its usual 

 mass of sand and shingle, laying bare ' a seam of coal ' extending from the front of 

 the cliff down to low- watermark, and how far beyond could not, of course, be said. 

 The seam was alleged to be from six to seven feet wide, and it had been dug out by 

 the fishermen and others to a depth of six feet without any signs of exhaustion, the 

 seam rather widening as it deepened. The coal was described as resembling the 

 ordinary kind, and burning well. The existence of coal in the Isle of Wight was a 

 fact by no means unknown, though it has been in a great measure overlooked. During 

 VOL. I. 3 H 



