On the Structure and Formation of Coal. 299 
March 5, 1884.—Prof. T. G. Bonney, D.Sc., F.R.S., 
President, in the Chair. 
The following communication was read :— 
1. “On the Structure and Formation of Coal.” By E. Wethered, 
ists, Hrs, EC.0. 
The author, having referred to the work of previous investigators, 
pointed out that seams of coal do not always occur in one bed, but 
are divided by distinct partings, some of which, as in the case of the 
Durham main seam, contain Stigmarie. It was important to 
notice this feature for several reasons, but especially as the beds of 
coal, defined by the partings, showed differences both in quality and 
structure. In the case of the shallow seam of Cannock Chase they 
had at the top a bed of coal 1 foot LO inches thick, the brown layers 
of which were made up of macrospores and microspores. The 
bright layers were of similar construction, except that wood-tissue 
sometimes appeared, also a brown structureless material, which the 
author looked upon as bitumen. He, however, objected to that 
term, and thought that hydrocarbonaceous substance would be 
preferable. What this hydrocarbonaceous material originated from 
was a question for investigation. In the lower bed of the Welsh 
* Four Feet” seam wood-tissue undoubtedly contributed to it; 
whether spores did was uncertain; it was true they could be 
detected in it. In the second bed of the shallow seam they had a 
very different coal from the upper one. It was made up almost as 
a whole of hydrocarbonaceous material. Very few spores could be 
detected. It was possible that the scarcity of these objects might be 
due to decomposition ; but the author’s investigations seemed to show 
that spores resisted decomposing influences more effectually than 
wood-tissue, which seemed to account for the fact that where they 
occur they stand out in bold relief againstthe other material composing 
the coal. Below the central bed of the shallow seam came the main 
division. In it the author detected a large accumulation of spores, 
but hydrocarbon formed a fair proportion of the mass. The author 
referred to other seams of coal from various parts of England, and 
pointed out the structure of each bed composing them. The con- 
clusions on the evidence elicited from his investigations were (1) 
that some coals were practically made up of spores, others were not, 
these variations often occurring in the beds of the same seam ; (2) 
that the so-called bituminous coals were largely made up of the sub- 
stance which the author termed hydrocarbon, to which wood-tissue”* 
undoubtedly contributed. 
An appendix to the paper, written by Prof. Harker, Professor of 
Botany and Geology at the Royal Agricultural College, Cirencester, 
dealt with the determination of the spores seen in Mr. Wethered’s 
microscopic sections. ‘Taking the macrospores, the resemblance to 
those of Jsoétes could not fail to strike the botanist. He had 
procured some herbarium specimens of Jsoétes lacustris in fruit, and 
20* 
