FOUND IN COAL FROM FORDEL. 193 



when acted on by heat and other causes, may have thus formed a continuous 

 layer of Middletonite in the seams of coal. At all events, the matter deserves 

 consideration. 



In conclusion, I think that this coal gives evidence of Sigillarias and Stigmarias 

 having entered into its formation, — of Acrogenous plants allied to Lycopodiacese 

 having also been present, as indicated by the abundance of peculiar sporangia, 

 and of the probable origin of Middletonite from the contents of these sporangia. 

 In the further prosecution of the subject, it will be interesting to observe if in 

 those coals which contain Middletonite similar sporangia can be detected. 



Explanation of Plate II., Figures 5 to 18. 



Fig. 5. Punctated woody tissue, apparently coniferous, from the needle-coal of Toplitz in Bohemia ; 

 from a specimen sent by Professor Harkness (magnified 190 diameters). 



Figs. 6 and 7- Dotted or Pitted vascular tissue (Bothrenchyma) from Arniston coal (magnified 190 

 diameters). 



Figs. 8 and 9. Pitted vascular tissue, from Fordel coal (magnified 190 diameters). This kind of 

 tissue is common in the carbonaceous matter, which is often found between the laminae of 

 coal and which soils the fingers. 



Fig. 10. Pitted vessel from coal with the dots elongated transversely, and giving a scalariform appear- 

 ance (magnified 190 diameters). 



Fig. 11. Scalariform vessels from coal, resembling those of ferns (magnified 190 diameters). 



Fig. 12. Seed-like bodies or sporangia, found in vast abundance in Fordel splint coal, natural size. 



Fig. 13. The same sporangia magnified about 8 diameters, imbedded in a mass of Fordel coal; some 

 lying on the surface, others projecting from the broken edges of the coal. They seem to 

 occur frequently in coal from different localities, both in Scotland and in England. Mr 

 Binney has seen them in Wigan coal. Similar sporangia occur in enormous quantity in 

 specimens of a brown inflammable deposit sent by Sir W. Denison from Van Diemen's 

 Land. 



Fig. 14. Section of Fordel coal, showing the sporangia as viewed by transmitted light, and magnified 

 20 diameters. The orange-yellow lines indicate the walls of the sporangia cut across in a 

 microscopic section. 



Fig. 15. Sporangium magnified 20 diameters. 



Fig. 16. Valves of sporangium separated, containing a quantity of black carbonaceous matter in its 

 interior (magnified 24 diameters). 



Fig. 17- Sporangium cut transversely, showing the internal cavity (magnified 24 diameters). 



Fig. 18. Sporangium cut obliquely, showing the cavity and the dark-coloured contents (magnified 

 24 diameters). 



