iv.] THE COAL IX THE FIRE. 97 



masses of vegetable matter get there ? The Yorkshire 

 and Derbyshire coal-fields, I hear, cover 700 or 800 

 square miles ; the Lancashire about 200. How large 

 the North Wales and the Scotch fields are I cannot say. 

 But doubtless a great deal more coal than can be got 

 at lies under the sea, especially in the north of Wales. 

 Coal probably exists over vast sheets of England and 

 France, buried so deeply under later rocks, that it 

 cannot be reached by mining. As an instance, a 

 distinguished geologist has long held that there are 

 beds of coal under London itself, which rise, owing to 

 a peculiar disturbance of the strata, to within 1,000 or 

 1,200 feet of the surface, and that we or our children 

 may yet see coal-mines in the marshes of the Thames. 

 And more, it is a provable fact that only a portion of 

 the coal measures is left. A great part of Ireland must 

 once have been covered with coal, which is now des- 

 troyed. Indeed, it is likely that the coal now known 

 of in Europe and America is but a remnant of what has 

 existed there in former ages, and has been eaten away 

 by the inroads of the sea. 



Now whence did all that enormous mass of vege- 

 table soil come ? Off some neighbouring land, was 

 the first and most natural answer. It was a rational 

 one. It proceeded from the known to the unknown. 

 It was clear that these plants had grown on land ; for 

 they were land-plants. It was clear that there must 

 have been land close by, for between the beds of coal, 

 as you all know, the rock is principally coarse sand- 

 stone, which could only have been laid down (as I 

 have explained to you already) in very shallow water. 



It was natural, then, to suppose that these plants 

 and trees had been swept down by rivers into the sea, 

 sc. H 



