EVIDENCE OF THE FOSSIL FLORA. 183 



tudinal fibres, and not unfrequently tlie medullary rays. Eiven 

 the trap-rocks of the district enclose, in some instances, their 

 masses of lignite, which present, in their transverse sections, 

 when cut by the lapidary, the net-like reticulations of the 

 coniferae. The fossil botanist who devoted himself chiefly to 

 the study of microscopic structure would have to decide, 

 from the facts of the case, not that trees were absent during 

 the Carboniferous period, but that, in consequence of their 

 having been present in amazing numbers, their remains had 

 entered more palpably and extensively into the composition 

 of coal than those of any other vegetable.* So far as is yet 

 known, they all belonged to the two great divisions of the 

 coniferous family, araucarians and pines. The huge trees of 

 Craigleith and Granton were of the former tribe, and approxi- 

 mate more nearly to Altingia excelsay the Norfolk Island 

 pine, — a noble araucarian, that reai-s its proud head from a 

 hundred and sixty to two hundred feet over the soil, and ex- 



* It is stated by Mr Witham, that, " except in a few instances, he had 

 ineffectually tried, with the aid of the microscope, to obtain some insight 

 into the structure of coal. Owing," he adds, "to its great opacity, 

 which is probably due to mechanical pressure, the action of chemical 

 afiinity, and the percolation of acidulous waters, all traces of organiza- 

 tion appear to have been obliterated." I have heard the late Mr Sander- 

 pon, who prepared for Mr Witham most of the specimens figured in his 

 well-known work on the ** Internal Structure of Fossil Vegetables," and 

 from whom the materials of his statement on this point seem to have 

 been derived, make a similar remark. It was rare, he said, to find a 

 bit of coal that exhibited the organic structure. The case, however, is 

 far otherwise ; and the ingenious mechanic and his employer were mis- 

 led, simply by the circumstance that it is rare to find pieces of coal 

 which exhibit the ligneous fibre existing in a state of keeping solid enough 

 to stand the grinding of the lapidary's wheel. The lignite usually occurs 

 in thin layers of a substance resembling soft charcoal, at which, from the 

 loose adhesion of the fibres, the coal splits at a stroke ; and as it cannot 

 be prepared as a transparency, it is best examined by a Stanhope lens. 

 It will be found, tried in this manner, that so far is vegetable fibre from 

 Iveing of rare occurrence in coal, --our Scotch coal at least, — that almost 

 every cubic inch contains its hundreds, nay, its thousands, of cells. 



