150 STEVENSON— FORMATION OF COAL BEDS. [April i8, 



Ziegler process for securing these substances from peat has been 

 tested on the commercial scale, with results approximating those 

 obtained by Thenius. 



Autochthonists claim that their doctrine is in accord with what 

 is known of nature's processes and that its fundamental assump- 

 tions can be verified by observation. They recognize that in some 

 respects, modern differ from ancient conditions. The distribution 

 of heat on the earth's surface is clearly unlike that during the Car- 

 boniferous ; the dominant plants of modern forests did not exist at 

 that time. But the Carboniferous plants have relatives in the 

 modern flora ; the chemical laws governing decay of plants have 

 remained the same throughout, as proved by a continuous record; 

 the erosive action of running water has shown no change in method ; 

 the laws controlling the deposit of transported materials have re- 

 mained unaltered from the earliest times. There have been great 

 changes in animal and vegetable life; many forms have become 

 fitted to new habitats; but such modifications are not unknown in 

 modern times and they are not regarded as strange. 



The modern peat bog is taken to be the analogue of the ancient 

 Goal bed. The vegetation is dissimilar, but that is unimportant. 

 Land-plant material, be it of one sort or another, gives peat under 

 the proper conditions. The final substance is practically the same 

 in the cedar swamps of New Jersey, the cypress swamps of the 

 southern states, the swamps of Scandinavia and in the buried 

 swamps of the southern states, the swamps of Scandinavia and in 

 the buried swamps of the Ganges, western India or the Mississippi ; 

 and, in all of those, it is the same as that in the great tropical 

 swamps of Florida, Demarara and Sumatra, where it is derived 

 from wholly different types of plants. Everywhere, the final result 

 of decomposition is the same; the plant material is converted into 

 a mass of organic acids and salts, enclosing large or small woody 

 fragments of resistant composition. The difference in plants does 

 not affect the matter under consideration; Carboniferous plants 

 were converted into peat when exposed to the proper condition, just 



