NOMOS. 179 



a trace, for the supposed soil is stratified in confor- 

 mity with the strata above and below it. In this 

 " dirt-bed " there are also a few upright stumps of 

 trees in an upright position, but these are very few 

 indeed. But in the majority of coal-seams there is 

 not a trace of either soil or root. Again, if the coal- 

 seam be the product of a forest growing on the spot, 

 and compressed into its present form, it may be ex- 

 pected that the coal would split in the direction of 

 the fibres of the trees which formed the seam, and, 

 as the trees would lie in all directions, that the coal 

 would split without any regularity in all directions ; 

 but what is the fact? The fact is, that the coal 

 splits in the plane of the seam, just as any slate-seam 

 would do. Again, if the coal-seam be formed from 

 the remains of a forest growing on the spot, it ought 

 to be thicker in some places than in others, according 

 as the circumstances were more or less favourable to 

 growth ; but the fact is, that the thickness of the 

 seam is uniform, or nearly so, and that the upper and 

 under surfaces are strictly parallel to the surfaces of 

 the sedimentary strata above and below them. Nor 

 is it easy to find a reason for the extreme thickness 

 of some of the coal-seams on the supposition that 

 these seams are formed by plants growing on the 

 spot, for the soil is exhausted and rendered incapable 

 of furnishing the necessary materials for the growth 

 of plants, even after a comparatively short time. In 

 a word, it is more easy to account for the formation 

 of the coal-strata by supposing them to be fossilised 

 drifts of vegetable matter, which had been deposited 

 at the bottom of the ancient lakes and seas in the 



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