222 



EDWARD C. JEFFREY 



It is universally admitted that all three types of coal shown in 

 the illustrations are formed as a result of water deposit. It will 

 be convenient at this stage to consider rather rare types of coal 

 which show considerable evidence of being derived from ancient 

 peat beds. Coals of this organization represent old swamps skirting 

 the sea and correspond, with certain necessary allowances made for 

 the difference of vegetation in the Paleozoic, to our existing tidal 

 mangrove estuaries. They are usually designated on this account 

 as paralic (paralisch of Naumann) coals. In some coals of this type 

 from Great Britain, Westphalia, and the Donetz coal field of Russia 



Fig. 4 



Fig. 5 



concretions have been found known as coal balls. A very good 

 account of these structures, particularly for the English examples, 

 was published, not long since, in the Philosophical Transactions 

 of the Royal Society of London.^ Our Fig. 4 shows the structure 

 of a coal ball from the Westphahan coal field in Germany, which 

 I owe to the courtesy of the Geologische Landesanstalt of Prussia. 

 In the lower part of the figure is the crushed stem of a young 

 calamite and the rest of the area is made up of less recognizable 

 remains. Fig. 5 illustrates the appearance of the coal adhering 

 to the outside of the same coal ball. It has been shown clearly by 



' Stopes and Watson, "On the Present Distribution and Origin of the Calcareous 

 Concretions in Coal Seams, Known as 'Coal Balls,'" Phil. Trans. Roy. Soc. London, 

 Series B, Vol. CC, 167-218. 



