72 STEVENSON— FORMATION OF COAL BEDS. [April 21. 



into a lake, in whicli would be deposited, in form of a delta, the vari- 

 ous elements which constitute the Coal Measures ; the plants, giving 

 the coal beds, would have been furnished principally by the luxuriant 

 forests which grew on the alluvial plains of the deltas. During and 

 after the formation of the Coal Measures, the movements of the 

 crust were so unimportant as to leave no apparent trace, so that to- 

 day one can easily find all the circumstances accompanying the for- 

 mation of the deposit. But these were not the conditions in either the 

 basin of Autun or in that of Blanzy and Creusot. There were 

 important movements of the crust during and after the Carbonifer- 

 ous and the Permian. 



In Autun the successive stages overlap in such fashion as to be 

 explained only by admitting, during the process of deposition, the 

 existence of crustal movements which modified profoundly the shape 

 of the basin. Further, it would be difficult to explain by this doctrine 

 why in Autun the important coal beds are in only the lowest part 

 of the formation, at the time when the alluvial plains of the deltas 

 were small; wdiereas, in the later part of the formation when those 

 plains should have acquired great extent and could support immense 

 forests, there were formed only some insignificant deposits in the 

 Upper Coal Measures. Similarly in the other basins of the Saone-et- 

 Loire, there were movements during the formation of the Coal 

 Measures and of the Permian, which caused the overlapping of 

 deposits. 



Delafond recognizes that the process of delta formation explains 

 the manner of deposit, the separation of the various materials, coal, 

 shale, sandstone; but the intervention of movements of the crust is 

 indispensable. 



De Launay '•'' remarked that it would not be incompatible with the 

 theory of deltas to believe that movements of the crust occurred 

 during the period of the Coal Measures and that they had given 

 progressively the great depth observed to-day. 



Almost at once after the appearance of Fayol's first publication, 

 de Lai)parent'" gave his adhesion to the new doctrine. His first 



" L. De Launay, "Reunion, etc.," p. 102, footnote. 



'"A. de Lapparent, " L'Origine de la liouillc," Assoc. Franc. Avanc. 

 Science. Conferences de Paris, 1892. The same in Rev. dcs quest, scien- 

 iifiqucs, Juillct, 1892. 



72 



