Note 32 — EVIDENCE OF THE SILURIAN MOLLUSCS—OF THE FOSSIL FLORA. ANCIENT TREE.

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 affinity, and the percolation of acidulous waters, all traces of organization appear to have been obliterated.” I have heard the late Mr. Sanderson, 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 misled, 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 being of rare occurrence in coal,—our Scotch coal at least,—that almost every cubic inch contains its hundreds, nay, its thousands, of cells.