[Illustration: Fig. 33.--Section from Cape Breton coal-field, showing four planes of vertical stems, and seven ancient soils with their covering of vegetation. _a_, sandstones; _b_, shales; _c_, coal; _d_, fire-clays; _e_, arenaceous shales.] The warfare seems now pretty nearly at an end, and as often happens in such cases, it has been found that each party was to some extent in the right and to some extent in the wrong. It has been ascertained that some coal-seams must have originated from the deposition of drift-wood in the mud and ooze of the sea-bottom, while others undoubtedly arose from the decay and entombment of vegetation in swampy plains of the land. That the latter mode of formation has been the usual one in most of our coal-fields has been generally acknowledged since Sir William Logan's announcement that each coal-seam, for the most part, rests upon a bed of fire-clay, which, with its embedded roots, marks the site of an ancient soil. This fact has been abundantly confirmed in every part of this country, and indeed wherever an extended series of coal-seams has been examined. Not only have the underlying fire-clays been found, but in not a few instances erect stems of trees, passing down through the coal-seam and spreading out their divergent roots in the clay below, exactly as they must have done when they flourished green and luxuriant in the times of the Carboniferous system. This was especially the case in the Parkfield Colliery, Wolverhampton, where seventy-three trunks were laid bare in the space of about a quarter of an acre, each with its roots attached. The same appearance was observed some years ago in the Dalkeith coal-field, where a group of erect trees was encountered covering a space of several square yards. Some instructive sections of such fossil-forests are given by Mr. Brown from the Cape Breton coal-field.[63] In one of them (Fig. 33) no fewer than four planes occur, each supporting its group of erect steins. Now, no one can glance over this and the other sections illustrative of the same paper, or the descriptions given by Sir Charles Lyell and others of the Nova Scotian coal-field, without being compelled to admit that the trees in question grew just where their upright stems can still be seen, and consequently that the accompanying coal-seams originated not from vegetation drifted by river-action, but from vegetation that grew upon the spot. And though erect stems do not exist in every coal-field, we seldom fail to detect the not less important occurrence of the fire-clays and hardened shales that support the coal-seams and prove by their embedded rootlets their identity with ancient soils. Thus we arrive at the inference that while in certain localities coal-seams have resulted from drifted vegetable matter, they have nevertheless for the most part been formed from plants that flourished where the collier now excavates, amid damp and dripping caverns, their carbonized remains.