TRANSACTIONS OF SECTION K. 811 



the formation of a ring of xylem. In Araucaria bidivillii division of tlie vascular 

 strand into two horsesboe-shaped masses was obseryed. 



The seedlings of Araucaria, section Colymbea, are cbaracterised by a much- 

 swollen hypocotyl. Each of the two cotyledons receives about five vascular 

 strands from the hypocotyl ; in the leaves a single bundle alone passes out from 

 the stem to each leaf. 



7. On the OcctLvrence of the Nodular Concretions (Coal Balls) in the Lower 

 Coal Measures. By James Lomax. 



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 difl'erent 

 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 difl'erent 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 observing the position in which 

 the nodules are embedded in the coal seam. It is well known that there is only one 

 seam of coal in which we find these nodular concretions, and to which diflerent 

 names are given in the difl'erent districts where it is worked. In 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 ; Shsffield, 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 orio-in, 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, Calamites, Lejndodendron /larcourtii; and the best 

 specimen of Rachioptcris grayii that has ever been found in the English Coal 

 Measures I discovered in one of these nodules from the roof. 



It is not my intention to enter into the chemical composition of these concre- 

 tions, 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 2 feet long and 

 1 foot in diameter. I have cut these in various directions to show the plant 

 tissues— how they ran, whether one nodule was coincident with its neighbour 

 (that is, if the tissues in the one nodule ran on into the next), and if the 

 tissues of one nodule ran parallel with those of a succeeding nodule either 

 lower or higher in the seam. In that object I have been very successful, as 

 the specimens will show. 



_ During these investigations it has been gradually forced on me that, at least 

 m this case, these plant remains have not grown on the spot where we now find 

 them, and for the following reasons :— In one nodule out of a number which were 

 joined together by the surrounding coal we have a portion of a transverse 

 section of Stigmaria, about one-half the whole section ; and in the nodule 

 adjommg to the right there is no portion of this Stigmaria whatever, but a 

 fragment of a longitudinal section of Amyelon radicans and Stigmarian 

 rootlets. In the one to the right above it there is still no part of it, and in the 

 one to the left we have no part of it either. It is so with the various masses I have 

 examined. Some we have which have contained nothing but Stigmarian rootlets; 

 their neighbours would contain Lijginodendron, Rachioptcris hihractensis, and 

 so on, in short pieces ; another, Stigmarian rootlets, with a short piece of 

 Lepidodoidron fuliginosum, whicli could not be seen from the outside of 

 the nodule, but was totally enveloped by the rootlets ; and so on. 



