144 ON THE FORMATION OF COAL v 



of which were closely allied to the existing club- 

 mosses. And if, as I believe, it can be demon- 

 strated that ordinary coal is nothing but 

 " saccular " coal which has undergone a certain 

 amount of that alteration which, if continued, 

 would convert it into anthracite ; then, the con- 

 clusion is obvious, that the great mass of the 

 coal we burn is the result of the accumulation of 

 the spores and spore-cases of plants, other parts of 

 which have furnished the carbonized stems and 

 the mineral charcoal, or have left their impressions 

 on the surfaces of the layer. 



Of the multitudinous speculations which, at 

 various times, have been entertained respecting 

 the origin and mode of formation of coal, several 

 appear to be negatived, and put out of court, by 

 the structural facts the significance of which I 

 have endeavoured to explain. These facts, for 

 example, do not permit us to suppose that coal is 

 an accumulation of peaty matter, as some have 

 held. 



Again, the late Professor Quekett was one of 

 the first observers who gave a correct description 

 of what I have termed the " saccular " structure 

 of coal ; and, rightly perceiving that this structure 

 was something quite different from that of any 

 known plant, he imagined that it proceeded from 

 some extinct vegetable organism which was 

 peculiarly abundant amongst the coal-forming 

 plants. But this explanation is at once shown to 



