On Carboniferous Coal Seams. By Edivard Wethered. 409 



other plants occur in coal or its neiglibourhood, they should be 

 considered foreign to the coal." Professor Huxley seems to have 

 been the next person to draw conclusions as to the origin of coal 

 from microscopic sections made of the " Better Bed " seam of York- 

 shire, the sections having been prepared by Mr. E. T. Newton, The 

 conclusions arrived at were stated in the ' Contemporary Eeview ' 

 for 1870 ; they were that coal was simply the sporangia and spores 

 of certain plants, other parts of which have furnished the carbonized 

 stems and mineral charcoal, or have left their impressions on the 

 surface of the layer. I may here state that Professor Huxley 

 does not claim to be the first to detect spores of plants in coal. 

 The first to discover them was Dr. Fleming, and Professor Morris 

 pointed them out in a note appended to Professor Prestwich's paper 

 on the Greology of Coalbrook Dale.* Later on I shall refer to other 

 observers who have noted the same fact. 



Sir William Dawson has also examined coal microscopically, but 

 he does not do so by making sections. The process is described on 

 page 494 of his very valuable work ' Acadian Geology.' Specimens 

 of coal were selected containing the tissue of only a single plant ; 

 these were boiled in strong nitric acid, and after the fumes had 

 subsided the residue was washed and submitted to microscopic 

 examination. By this method Sir William Dawson has obtained 

 and figured f tissue of Sigillarise, Calamites, Ferns, and scalariform 

 vessels of Lepidodendron. Whether these remains can be considered 

 as typical of the coal-forming vegetation is, I think, doubtful, and 

 for this reason. First, I object to the principle of specially selectiug a 

 piece of coal for examination ; if we detect a fragment in a seam 

 better preserved, with regard to structure, than the rest of the mass, 

 the very fact should invoke caution, as there may be a cause for the 

 better preservation. It may be due to the fragment being a foreign 

 element (foreign, I mean, so far as the geneml mass of the coal is 

 concerned), which has resisted decay better than the vegetation 

 which has formed the mass of the coal. Second, when coal is 

 treated with nitric acid dense fumes come off; this implies that 

 something is undergoing destruction, and the importance of the 

 loss is only known when we obtain microscopic sections. Sir 

 William Dawson admits that two difficulties have impeded his 

 investigations, " and have in some degree prevented the attainment 

 of rehable results." One of these, he says, "is the intractable 

 character of the material as a microscopic object ; the other the want 

 of sufficient information with regard to the structure of the plants 

 known by impressions of their external forms in the beds of the 

 coal formation." 



I will now proceed to give an account of my own investigations, 



* Geol. Trans., Second Series, vol. v. 



t 'Acadian Geology,' 3rd edition, p. 464. 



