i9'3.] STEVENSON— FORMATION OF COAL BEDS. 137 



of vegetable matter. Grand'Eur}', seeing evidence only of quiet 

 deposition, did not recognize the agency of violent floods ; the vege- 

 table debris underwent disintegration and decomposition on the land 

 whence it was removed by rain and ordinary floods. There seems 

 to be no positive assertion in any part of Fayol's work that the floods 

 were of extreme violence, but the torrential character of the streams 

 and their great carrying power are essential features of his explana- 

 tions. De Lapparent stated the matter with clearness, when he 

 asserted that, in the Central Plateau, vegetable masses descended 

 en bloc and were deposited as localized coal beds ; so that a single 

 flood might make a coal bed of any dimensions. Renault conceived 

 that as there was no ice cap at the poles, the rainfall was greater, 

 the floods more violent and the quantity of transported vegetable 

 materials much in excess of the present, because the surface was cov- 

 ered with a vegetable growth surpassing that now found in the tropics. 

 Lemiere thought of deep lakes or lagoons fronted by vast low-lying 

 plains ; the contributing area was between the levels of low and high 

 water ; it was swept clear of vegetation during floods ; a mass of 

 vegetation removed en bloc might present the appearance of forma- 

 tion in situ; during low water, the streams would bring in little aside 

 from inorganic materials. For Stainier, the plants grew on the con- 

 tinent, whence they were swept into depressions along with inorganic 

 materials, the mass being assorted by specific gravity ; the Stigmaria 

 being denser, sank into the underclay. 



The flooding of vast lowland areas is not hypothetical; the 

 writer, in Part II. of this work, has cited many authors to show 

 that, in the Ganges, Yang-tse-kiang, Amazon, Zambesi, Mississippi 

 and other extensive drainage areas, great floods are only too familiar 

 features ; that for long distances, at times hundreds of miles, the 

 lowlands are covered to the depth of many feet in strips 40 to 100 

 miles wide; the depth in some cases being such that only the tops 

 of the highest trees can be seen. The water for these' floods comes 

 at times from highlands far away and is not that from rainfall over 

 the flooded region ; at other times, the storms originating in distant 

 highlands pass over the area before the flood reaches the plain ; but 

 the characteristics are practically the same in all cases. The flood 



