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



Sapropel ; the gradations from peat to coal ; and asserts that all point 

 toward autochthony. He antagonizes conclusions drawn from the 

 presence of vegetable matter in material obtained by deep-sea dredg- 

 ing in the Gulf of Mexico, for that is mingled with ooze and proves 

 nothing for transport. He maintains that vegetable pulp cannot be 

 transported far without notable loss and he urges that black waters 

 from swamps soon lose their color through oxidation, as appears 

 from conditions in the Congo, Rio Negro and other rivers. De Lap- 

 parent has protested agamst the " fascination of present causes " and 

 Schmitz admits willingly that it is an error to seek in the present an 

 absolute representative of the past ; but he asserts that it is equally 

 an error to disregard the present in the study of the past. 



Schmitz presents an elaborate argument. He traces the for- 

 mation of Sapropel in an arm of the sea, the encroachment of vege- 

 tation, the formation of a bog covered by trees — the tourbicrc 

 boiscc, the loss of moisture and the destruction of the forest, the for- 

 mation of the moss bog with Sphagnum,, Scheuchscria, etc. — the 

 tourbicrc bonibcc or hochmoor, which may continue to rise until it 

 reach the heath stage — that of final decrepitude. He shows how this 

 normal development is often interrupted, that a newer stage may 

 return to an older stage or may originate without existence of pre- 

 vious stages. 



The wooded bogs are modern representatives of the Carbonifer- 

 ous type. They show conditions observed in the coal beds ; peaty 

 maceration disintegrates the most resistant plants so that one rarely 

 recognizes the parts. The mode of growth in bog plants resembles 

 that of the coal plants ; the root is radial not tap. He describes an 

 extensive bog in Hanover, in which the peat had been burned, leaving 

 exposed great tree-trunks, the luxurious crown existing when the bog 

 was wooded; if that bog had been covered with sediment during the 

 life of those trees, there would have been a legion of autochthonous 

 tree-trunks. 



The immensity of the great coal areas, to be compared with the 

 immensity of modern bogs, must not be disregarded. One cannot 

 think of the great Westphalian-Belgian-English basin as a mere 

 lagoon to be fdlcd l)y rivers ; and Schmitz asks how vast must have 



104 



