Notes . 
603 
ON THE OCCURRENCE OF THE NODULAR CONCRETIONS 
(COAL BALLS) IN THE LOWER COAL MEASURES During 
the last fourteen or fifteen years that I have worked amongst fossil 
coal plants, I have been struck with the diversity of ways in which 
the different genera and species of plants occur in the different 
calcified nodular masses which we find so plentiful in the several 
localities where they are found embedded in the coal. 
At the meeting at Bradford in 1900 there was a joint discussion 
between the Geological and Botanical Sections as to whether the 
plants which entered into the composition of the different coal seams 
grew in situ or not, and from that discussion I gathered that the 
opinions were evenly balanced. Consequently, from that time to 
the present I have taken a very great interest in the position in which 
I have found the nodules embedded in the coal seam. As we all 
know, there is only one seam of coal in which we find these nodular 
concretions, and which is given different names in the different 
districts where it is worked. Ifi the Yorkshire district it has the 
name of the Halifax Hard Bed; in Oldham, the Upper Foot Mine; 
Bacup, the Mountain and Union Mine; Todmorden, which includes 
Dulesgate, the Union Mine ; Sheffield, the Gannister Mine ; and so on. 
But, where it is found, in nearly all cases the roof contains similar 
concretions, with this exception — that the fossil remains contained 
therein are of marine origin, while those found in the coal underneath 
are always of vegetable origin. Sometimes, but not very often, we 
may find a stray stem in the nodular concretions from the roof, such 
as Dadoxylon , Catamites , Lepidodendron Harcourtii ; and the best 
specimens of Rachiopteris Grayii that have ever been found in the 
English Coal Measures I found in one of these nodules from the roof. 
It is not my intention to enter into the chemical composition of 
these concretions, only so far as to state that in most cases they 
consist of calcium carbonate and iron pyrites in varying proportions ; 
and in a few places we find that there is a mixture of silica with the 
carbonate of lime. I have obtained from three localities portions of 
the seam with these concretions of various sizes embedded in the coal. 
Some of the pieces I have obtained have been over two feet long and 
one foot in diameter. I have cut these in various directions to show 
1 Abstract of paper read before Section K of the British Association, Belfast, 
1902. 
