322 BULMAN : THE THEORY OF THE FORMATION OF COAL, 



And there is a great difficulty in conceiving how any deposit of 

 vegetable matter formed on land can be gradually lowered beneath 

 the sea without suffering extensive denudation. This was brought 

 vividly to my mind during a recent examination of the so-called 

 submerged forest on the Norfolk coast. A little to the north of 

 Hunstanton a very good exposure of it can be seen at low water. 

 The peaty layer, with tree-stumps resting on clay, is much cut up by 

 the sea, and really exists only in patches. If it were covered now 

 and preserved from further denudation, it would form a coal-seam of 

 isolated fragments, each a few square feet in extent. And, on the 

 gradual subsidence theory, every layer of vegetable matter would be 

 exposed for a time to the action of the waves between tide-marks. 

 This, however, does not apply to the seams of the Coal Measures 

 proper, which may have been formed in great land-locked areas, 

 where the open sea was excluded. But for the Bernician series, 

 with its numerous limestones, the open ocean is required. 



The position, then, of this Beadnell coal favours rather the drift 

 theory of the origin of coal. We may suppose the vegetable matter 

 to have been laid down when the water became too deep and the 

 area too far from land to receive even the fine sediment which formed 

 its under-clay, and before it became fit for the formation of lime- 

 stone. 



This is in accordance with the views advocated by Mr. Good- 

 child, F.G.S., of the Geological Survey, in the Geol. Mag., Feb. 1890. 

 Mr. Goodchild points out how the vegetable matter carried down by 

 rivers will drift out to sea beyond the zones of ordinary sedimenta- 

 tion, and, sinking down, form layers of coal. Thus it would happen 

 that a seam of coal would usually succeed a very fine-grained deposit. 

 And this is what we actually find with most of our coal-seams. 



M. H. Fayol, too, in his great work on the 'Coal-field of 

 Commentry,' has shown that vegetable debris carried down by rivers 

 is deposited in the quieter portions of the basins of reception, away 

 from the influence of currents, and out of reach of even the finer 

 sediments under normal conditions. M. Fayol asserts that all 

 varieties of coal are formed thus directly from vegetable matter 

 carried by water ; and although we cannot accept so wide a generalisa- 

 tion, we must admit that he has proved his case for the coal of 

 Central France, if any case can be proved by facts and reasoning. 



For this particular seam of coal, then, I think some modification 

 of the drift theory must be adopted. And if so, we must infer tliat 

 the presence of an under-clay beneath a coal is not necessarily 

 evidence of growth in situ, and, further, that the said under-clay is 

 not always a terrestrial accumulation. 



Naturalist, 



