712 the WONDERS OF GEOLOGY. Lect. VII. 



33. Fossil Plants of the Coal. — I proceed to 

 the examination of the flora of the carboniferous epoch. 

 The layers of pure coal, as we have already stated, are 

 wholly composed of carbonized vegetables ; and when we 

 consider that these beds are from ten to thirty feet in thick- 

 ness, and in some instances amount even to sixty feet,* it 



gaseous products of the wood dispelled, while the essential characters 

 of the fibrous and cellular structure are undisturbed. The unconsumed 

 portions, which alone constitute the true vegetable frame-work, are 

 thus, as it were, mounted in the fluid silica. This property of vege- 

 table fibre, of retaining its form, notwithstanding the action of a high 

 temperature, suggested to me the probability of detecting structure in 

 the ashes of coal ; and upon examination, I found that the white ashes 

 of ' slaty coal ' furnish most beautiful examples of vegetable remains." 

 In a subsequent paper the author adds the following remarks : — 

 " Having ascertained that the siliceous organization of recent plants is 

 not destructible, even under the blow-pipe, it appeared to me a 

 natural inference, that the less intense heat of a common fire would 

 not destroy this siliceous tissue in the coal-plants ; and my opinion has 

 been confirmed, for I have detected in the white ashes of coal all the 

 usual forms of vegetable structure, viz. cellular tissue, smooth and 

 spiral fibre, and annular ducts. A comparison of the ashes of coal with 

 those of recent plants, would doubtless afford some further insight into 

 the nature of fossil vegetables. To mention only one instance — 1 have 

 ascertained that the lumps of carbonized matter, which occur abun- 

 dantly in the upper sandstone near the Spa at Scarborough, are, in al 

 probability, portions of the stems of some arundinaceous or gramineous 

 plants. The structure of the epidermis is precisely similar to that of 

 the oat, consisting of parallel columns, set with fine teeth, dove- tailing, 

 as it were, into each other, while the underlying tissue consists of 

 cubical cells, a thin horizontal section exhibiting a series of squares- 

 From these facts it is evident, that the true framework and basis of 

 vegetable structure in the plants of coal, is not only entirely indepen- 

 dent of carbon, but that it has also resisted the bituminous decompo- 

 sition, which has converted all the carbonaceous materials into a 

 highly inflammable substance." — Rev. J. B. Reade, F.R.S. on the 

 Structure of the solid materials found in the Ashes of Recent and 

 Fossil Plants. — Journal of Science, vol. ii. p. 413. 



* In England, the thickest bed of coal, amounting to thirty feet, is 

 in the Dudley basin. In Poland, there is a continuous mass of coal, 

 sixty feet thick.— Sir R. Murchison. 



