Base Exchange and the Formation of Coal

Abstract

IN an article entitled “Base Exchange and the Formation of Coal” (NATURE, Sept. 24,. 1927) I discussed the probable influence of base exchange between the roofs of coal seams and sodium chloride solutions on the formation of bituminous coal. I suggested that base exchange might form the connecting link between the coal seams of various geological formations. Since writing the article, I have had an opportunity of examining the roofs of bituminous coal seams of Jurassic, Cretaceous, and Tertiary ages, and they agree with those of the Carboniferous age in showing evidence of base exchange and hydrolysis. It appears, therefore, that bituminous coal always occurs under a roof which has undergone base exchange and which contains sodium as the main replaceable base. The final stage in coal formation appears to have been the bacterial decomposition of the accumulated plant material under alkaline anaerobic conditions.