AND OTHER VARIETIES OF COAL. Ill) 



tig. 3). These are found in every part of the coal, in greater 

 or less number, and they occur also in patches in the cement- 

 stone covering it. They are almost exactly of the same size 

 as the polygonal spaces shown in Plate IX , fig. 2, to illustrate 

 the action of heat. I can conceive no other interpretation of 

 these spaces than that they are actual vegetable cells, much 

 less changed than those before named. 



3ixl. The dark-brown material between the yellow masses 

 is very scanty and granular where these masses almost merge 

 into each other ; elsewhere it is in considerable quantity, and 

 is studded at slight intervals with patches of a yellow, red, 

 brown, or almost black colour, in shape elongated, angular, 

 rounded, bifurcate, and bent or even coiled. These make up 

 a large portion of the whole substance between the yellow 

 masses. 



In vertical sections, this dark-brown matter forms lines 

 which traverse the section in the direction of the laminee of 

 bedding, and are obviously the same lines as give the striated 

 appearance to the surfaces of small blocks examined as opaque 

 objects. The edges of vertical sections (Plate VII., fig. 4), 

 are very instructive, for on them the vegetable fibres and shreds 

 of membi'ane which are seen indistinctly in the substance of 

 the sections project boldly, so as, I think, to compel the 

 observer to one conclusion, that they are vegetable tissues. 

 The dark-brown matter separating the yellow or reddish-yellow 

 masses of other cannels is of a similar kind to that in the 

 Torbanehill, 



The general structure of the Torbanehill coal is further 

 illustrated by occasional opportunities of examining the rela- 

 tion which exists between it, as shown in Plate IX., figs. 

 3 and 4, and portions of easily recognisable vegetable struc- 

 ture. In fig. 3, an irregularly elongated, brownish-red mass, 

 without obvious structure, lies in coal having the same ap- 

 pearances as that found in the lower part of the seam, and 

 shown in Plate IX., fig. 4 ; and it will be observed, that from 

 this mass the septa between the yellow bodies of the coal 

 appear to radiate. In other parts similar masses are seen in a 

 structure more like that observed in the upper parts of the 

 seam. In these, too, the brownish-red matter stretches into 

 the yellow, and marks it out into a number of spaces. Again, 

 in Plate IX , fig. 4, a band of reddish and apparently fibrous 

 matter spreads out over a considerable quadrangular space, 

 dividing it into polygonal yellow spots ; and, on leaving it at 

 the opposite angle, what appear to be fibres are again col- 

 lected into a narrow band. 



From the general description of the structure of this coal, 



