312 FOSSIL FLORA 



Parkfield near Wolverhampton, where, in connection with a deposit 

 not exceeding 12 feet in thickness, are three distinct beds of coal, 

 each exhibiting, on its surface, forests of large upright trees ; on the 

 upper surface seventy-three trees were standing within an area of one 

 quarter of an acre. The New "World furnishes additional facts. Sir 

 Charles Lyell found in the Coal-measures of Nova Scotia at the South 

 Joggins, erect trees at ten different levels, extending over a space of 

 about fourteen square miles. The trunks, which were abruptly broken 

 at the top, passed through different mineral beds, but were never seen 

 to penetrate a coal-seam, however thin ; they terminated downwards 

 either in coal or shale, having grovra, either out of decomposed vege- 

 tation, or out of a swampy muddy soil. Mr. Brown describes similar 

 instances in the Sydney coal-field of Cape Breton, where the upright 

 trees generally are rooted in the shale or mud beds, — the marshy soil 

 of the Carboniferous era. 



The conclusion, which these facts prove, is remarkably confirmed 

 by the peculiar relation which the underclay has to a coal-bed. 

 It was first observed by Mr. Logan, that below every one of the 

 hundred coal-seams in South Wales, there is a bed more or less 

 argillaceous and mixed with sand, usually of a fine texture, and 

 making a good fire-clay. Now every one of these beds is penetrated 

 in all directions by a tangled collection of fossil roots (Stigmaria 

 ficoides), from which numerous rootlets proceed, interlacing with 

 each other. In Britain generally, and in North America, the same 

 relation has been observed. Some few exceptions occur in our own 

 district, but even here interesting instances can readily be found. 

 Beneath a coal at Shilbottle there is a bed of carbonaceous shale, 

 () feet thick, almost entirely composed of Stigmarise with long root- 

 lets attached, and so highly charged is this bed with carbon, that it 

 can be advantageously used to burn lime. Indeed, there seems no 

 doubt that the underclay was the soft, damp, miiddy soil on which 

 the Carboniferous Flora grew ; the form, and sometimes the struc- 

 ture of the roots remain to reveal to us their nature and history, but 

 the gigantic stems and enormous vegetation which they supported 

 have been transformed into coal. 



We must find analogies in existing nature to give force to our 

 exposition ; for modern geology, discarding the fanciful conjectures 

 which gave poetic interest, but no philosophical value, to the cosmo- 

 gonies of a former generation, appeals to the laws now operating to 

 furnish an explanation of the past. Accumulations of peat, so 

 abundant in this district, give us an illustration. This is formed 

 when vegetables moulder in moist situations ; in the lower part of a 

 deposit, it consists chiefly of trunks and branches of trees, of reeds 

 and sedges, and in the upper part of the remains of various species 

 of Sphagnum or Moss, which throw out new shoots as the older 

 decay, so that an increase in the height of the deposit is constantly 

 going on, as long as the proper condition of moisture continues. It 

 is found at all levels in this county, from the sea-coast up to the 

 summit of Cheviot, and not unfrequently of considerable depth, as 

 near to Ford, where it is about 20 feet deep. Peat accumulations 



