On Carhoniferous Goal Seams. By Edivard Wether ed. 411 



Then comes the " Best Coal " or bottom and chief bed of the 

 seam. The lustre throughout is fairly bright, which appears to be 

 due to the numerous thin bright layers. In the dull lustrous por- 

 tion of the coal macrospores and microspores were numerous, but in 

 the bright portion hydrocarbon was the chief constituent. 



'i'he variations in the beds of coal which constitute the " Shallow 

 Seam " illustrate the importance of investigators taking a complete 

 stratagraj)hical section of each seam of coal to which they turn 

 their attention. The top bed is not freely combustible, but when 

 combustion has fairly commenced, considerable heat is generated. 

 The " Bright Coal " is mainly worked for gas purposes, and the 

 " Best " for gas and household use. A mixture of the " Hardens " 

 and "Best" beds makes a most economical fuel, but require a 

 good draught. 



I next take the Welsh " Four Feet " seam celebrated throughout 

 the world for its smokeless properties. For samples of this seam 

 and permission to inspect it underground, I am indebted to the 

 owners (Messrs. Greo. Insol and Son) and to the manager of the 

 Cymmer Colliery near Pontypridd, South Wales. At this colliery 

 the " Four Feet " presents the following sections. 



Section of tee Foue-Feet Seam, CYitviER Colliery, near Pontypridd, 

 South Wales. 



Description. 



Top bed. Coal brittle, -with 

 bright lustre. 



Argillaceous parting 



Middle bed. Medium lustre 



Argillaceous parting 



Lower bed 



Argillaceous parting 



Bottom bed 



Undercliy 



Structure. 



Ciirbonized vegetable tissue, witli 

 a little bydrocarbou. 



Miniature underclay. Stigmaria. 



Highly carbonized vegetable 

 tissue. 



Miniature underclay. 



Well-preserved scalariform tissue 

 at the top close imder the 

 parting. Beneath spores and 

 spore cases, with other vege- 

 table substances. 



Stigmaria. 



Inferior coal, not worked. 



Stigmaria. 



From the fact of this seam being termed the " Four Feet," 

 persons may be led to regard it as constituted by four feet of coal 

 only ; that, however, is not the case. The stratagraphical section 

 shows the seam to be made up of four distinct beds of coal separated 

 by clay partings which are miniature underclays ; the lowest of 

 these coals I have, unfortunately, not had an opportunity of 

 examining. The top one of all is merely a mass of carbonized 

 vegetable tissue, with a Kttle hydrocarbon. The coal, however, was 



