178 ON THE ORIGIN OF COAL. 



depth of eleven hundred feet from the surface, a 

 magnificent specimen of Sigillaria, which exhibits 

 in the stem the respective characters of the species 

 pachyderma^ reneformis, and organum, and true 

 Stigmarise traced eighteen or twenty feet as its 

 roots. The stem was about two feet high, and 

 could not be traced into the Coal and Cannel 

 seam above. Four main roots appeared to have 

 proceeded from the base, but only one has been 

 preserved entire and lodged in the museum of the 

 Manchester Geological Society. This, after 

 proceeding some distance, divides into two roots, 

 and each of these latter into two more, which run 

 in a horizontal direction as Stigmaria, at a depth 

 of two feet under the Coal. Their extremities 

 have not been reached, although they were traced 

 upwards of twenty feet. 



The matrix in which they occurred was a dark 

 coloured fire clay, which contained so much car- 

 bonaceous matter as to prevent the rootlets of 

 Stigmaria or any other fossil remains from being 

 easily traced in it ; but it was very evident that 

 the destruction of an immense number of these 

 bodies had caused the dark colour of the clay, as 

 they could be distinctly seen on dividing the 

 moistened clay with a penknife. 



