19"] STEVEXSOX— FORMATION OF COAL BEDS. 73 



publication was in 1887; in 1892 he presented his views in vigorous 

 fashion. The statements are made with that clearness and precision 

 which characterized his writings, so that it is well to give the synopsis 

 in detail. 



The early observers regarded coal as due to transported vegetable 

 materials but the fascination of actual conditions, as exposed by 

 Lyell, led men to abandon that explanation and to see in the vast peat 

 bogs of this day the modern representative of coal beds. De Lappa- 

 rent gives a synoptical statement of the peat bog theory. He thinks 

 this doctrine deserving of a double reproach — it draws no argument 

 from the nature of the coal itself" and it does not consider suffic- 

 iently the topographical conditions of each bed. 



De Lapparent says that coal, especially in the great maritime 

 basins, has wholly mineral aspect, laminated, with conchoidal fract- 

 ure and showing no sign of organization ; even thin sections show 

 only amorphous material with rare indications of cellular structure. 

 In most cases, chemical and microscopical examination must be com- 

 bined, but sometimes the former is unnecessary. Fayol discovered at 

 Commentry, in 1883, lenticular brilliant zones which proved to be 

 flattened stems. Grand' Eury, in 1876, asserted that the coal of the 

 Loire basin was formed of vegetable remains laid flat in a position 

 uniform enough to suggest a liquid in repose. Several beds at Saint- 

 Etienne consist wholly of Cordaites bark and the Grande Couche at 

 Decazeville is composed of bark of Calmnodcndron. This determina- 

 tion, first made by Grand' Eury, is interesting as showing that the 

 leaves, barks, etc., play in the coal the same part that vegetable im- 

 prints do in the shale. The ulmic matter, resulting from maceration 

 of vegetable detritus, formed the sediment in which the recognizable 

 remains were buried. 



To explain the origin of this amorphous material, he cjuotes 

 Saporta, who relates graphically the conditions existing in the dense 

 forests of the hot, humid Carboniferous time. The rapidly accumu- 

 lating mass of leaves, loose internal material from tree trunks, was 



" It is well to remark in passing that de Lapparent's statement was made 

 54 years after Link's investigations, 2<3 years after Dawson's publications in 

 the Q. J. G. S. and 9 years after publication of v. Giimbel's elaborate 

 researches. 



73 



