THE MODE OF ORIGIN OF COAL 229 



with organic materials, would be torrential in its action. As a 

 matter of fact, judging from actual conditions, given abundance 

 of time, almost unlimited accumulation of vegetable remains in 

 water, without any appreciable admixture of mineral matter, can 

 be accounted for, particularly since vegetable substance once per- 

 manently covered by water is practically imperishable. 



A very serious objection to the peat h3qDothesis of the origin 

 of coal lies in the observed fact that peat bogs are not found in the 

 parts of our present world which in their climatic warmth corre- 

 spond to the probable conditions obtaining during the great coal 

 age, the Carboniferous. Vegetable matter not continuously 

 covered by water quickly disappears in tropical climates. True, 

 Potonie has called attention, in his truly monumental work^ on 

 peat and similar formations, to the existence of what he considers 

 to be a true peat bog in central Sumatra. The illustrations given 

 show clearly, however, that there is present a filled body of water 

 with trees growing upon its scarcely elevated surface. The organic 

 material, moreover, as figured in Potonie's work, contains large 

 quantities of pollen, thus showing its essentially open-water 

 origin. There can be no reasonable doubt that it was as impossible 

 for vegetable matter to accumulate on land, even on wet land, in 

 the Carboniferous and later periods in the Mesozoic and Tertiary, 

 as it is in subtropical and tropical climates at the present time. 



We are then apparently brought to the conclusion, both from 

 the conditions of peat formation in the present age on the one hand, 

 and from the actual organization of the commonest and most 

 abundant coals of every geological age and in all parts of our earth, 

 on the other, that the raw materials of coal were heaped up, not 

 as the result of the growth of successive generations of plants on the 

 prostrate and persistent bodies of those already fallen, but as the 

 age-long gradual accumulation of vegetable matter in open water. 

 In other words, coal is not a compost heap but a sedimentary 

 deposit. Striking as are our actual peat bogs in temperate climates, 

 in reality they throw no light on the accumulations of vegetable 

 matter in past ages, which have been preserved to us in the form of 

 coal. The less conspicuous accumulations of vegetable matter 



' Die Recenten Kaustohiolithe u. ihre Lager staetten, Berlin, 1908-12. 



