50 DESCRIPTION OF FOSSIL TREES DISCOVERED 



cognise decided appearances of vegetable matter, and in several varieties the 

 texture is so compact or crystalline, that were analogy inapplicable, they 

 could not be considered as organic. This is more especially the case with 

 glance-coal, as also with the variety called pitch-coal. That coals are in 

 general of vegetable origin, is therefore a proposition made out by analogi- 

 cal reasoning. I have, however, been so fortunate as to discover certain 

 most decided traces of organic tissue, in one or two varieties of the more 

 compact and mineralized coals. The observations which I have to offer on 

 this subject will be best illustrated by direct reference to Plate XI. 



Fig. 1. Represents, of the natural size, a fragment of Bovey Coal. This 

 variety is evidently dicotyledonous or gymnospermous phanerogamic, for it 

 presents all the external characters of stems belonging to that class. It is 

 somewhat strange, however, that the sections, however carefully made, do 

 not present very decided characters under the microscope. 



Fig. 2. Represents a portion of a transverse slice, in which are seen in- 

 dications of a tissue resembling that of the Coniferse ; but I have not suc- 

 ceeded in obtaining more decided appearances. 



Fig. 3. Represents two portions of a piece of jet. The upper dark portion 

 is part of a longitudinal section, of the natural size, in which the woody 

 layers are distinctly seen. The lower is part of a transverse slice, viewed 

 with the microscope. Indications of the woody layers are observed, but in 

 other respects the tissue is completely obliterated. 



In some species of Cannel Coal from Lancashire, I have certainly found 

 decided traces of organization ; but to what family they may have belonged 

 I am unable to say. 



Fig. 4. Represents a transverse slice of one of these specimens. 



Fig. 5. Is the representation of a longitudinal slice. 



The appearances, however, are so undecided, that, although I should be 

 inclined to consider them indicative of a monocotyledonous plant, I shall 

 not venture upon any conjecture respecting them. 



Many varieties of Coal, from Berwick-on-Tweed, and the Scotch basins, 

 on being subjected to heat, split into pretty regular layers, like those of an 

 exogenous tree ; but I have found no traces of tissue in them. I am in- 



