0)1 some of the Modes of Formation of Coal Seams. 97 



Whickljope Burn, near first bniucli above Cross Sike, Nortliuiuberland ; 

 riat. size. 2 a. Leaf-scar, enlarged. Ilor. Calciferous Sandstone Series ; 

 communicated by Mr n. Miller, F.R.S.E. 3. Loc. Railway-cutting between 

 Kates Mill and Boags Mill, Water of Leith, Midlothian. Ilor. Calciferous 

 Sandstone Series ; collected by Mr J. Beniiie ; nat. size. Specimen in the 

 Collection of the Geol. Survey of Scotland. 3 a. Leaf-scar, enlarged. 4. Loc. 

 Shore, Wardie, ]\lidlothian. Jlor. Calciferous Sandstone Series ; nat. size ; 

 collected by Dr J. M. Macfarlane. 4 a. Leaf-scar, enlarged. 



Figs. 5, 6. Bothrodcndron ininuti folium, Boulay, sp, 5. Loc. Shale over 

 Whistler Seam, Bonnington Pit, Kilmarnock. Ilor. Lower Coal-measures ; 

 nat. size ; communicated by the Rev. D. Landsborough, 5 a. Leaf-scar, 

 enlarged. 5 h. Subepidermal cicatricules, enlai-ged. 6. Loc. Shale over 

 " Barnsley Thick Coal," Monkton Main Colliery, near Barnsley, Yorkshire; 

 Middle Coal-measures ; collected by Mr W. Hemingway ; nat. size. 



XII. On some of the Modes of Formation of Coal Scams 

 (Abstract). By J. G. Goodchild, Esq., H.M. Geol. 

 Survey, F.G.S., Acting Instructor in Geology and Miner- 

 alogy to the Eoyal Geographical Society. 



(Read 17th April 1889.)i 



After briefly noticing the chemical and physical characters 

 of coal, and its relations to the strata enclosing it, the author 

 discussed the nature of the conditions essential for its forma- 

 tion. These require simply that a requisite quantity of pure 

 vegetable matter should be left under conditions that ensure 

 its fossilisation before its constituents shall have passed 

 entirely into the inorganic condition. These conditions may 

 be fulfilled in any one of many different ways. Inland, for 

 example, coal might be formed through the burial of peat 

 beneath deposits carried into inland lakes. In marine areas 

 it may originate through the sedimentation of inland peat- 

 beds that have been resorted ; or it may arise through the 

 submergence and subsequent burial of maritime beds of peat 

 entombed in situ. The burial of masses of drift timber has 

 been a common factor in the production of some irregular 

 seams of coal. The decay of marine vegetation, alg£e, and 

 the like, and of the spores emanating from these, can hardly 

 be left out of account. The growth, decay, and subsequent 



^Subsequently printed in the ''Colliery Guardian," and also in the 

 " Geological Magazine " for July 1SS9. 



VOL. X. G 



