364 SCIENCE PROGRESS. 



Dawson adopted the method of chemical treatment in 

 his investigations on the minute structure of coal, and has 

 been able to identify numerous fragments of scalariform and 

 pitted vessels, and other tissue elements ; he was led to the 

 conclusion that the existence of spore-bearing beds is an 

 exceptional rather than a common occurrence. In speaking 

 of the nature and origin of coal, Dawson sums up the 

 question as follows : " In short, a single trunk of Sigillaria 

 in an erect forest presents an epitome of a coal seam. Its 

 roots represent the stigmaria underclay ; its bark the compact 

 coal ; its woody axis the mineral charcoal ; its fallen leaves, 

 with remains of herbaceous plants growing in its shade, 

 mixed with a little earthy matter, the layers of coarse coal." l 



Some further information as to the occurrence of spores 

 in coal is contained in a contribution by E. T. Newton, in 

 which special attention is directed to the numerous spores in 

 the Australian white coal or Tasmanite; the name Tasmanite 

 punctatus was suggested for these spores, but it has not been 

 generally adopted, and, indeed, such a designation does not 

 seem particularly appropriate. 



We are indebted to another English geologist, Wethered, 

 for additional facts as to the various spore coals ; he has 

 figured and described several forms of macrospores and 

 'microspores in the Better bed and other seams. He 

 points out the abundance of spores in the dull layers of 

 certain kinds of coal, and suggests the rather unfortunate 

 term, hydrocarbon, for the structureless substance which 

 chiefly constitutes the bright patches in coal seams. 



Brief reference must be made to the work of Reinsch, 

 whose patient investigations resulted in the discovery of 

 numerous structures in coal which he was at a loss how to 

 dispose of in any existing classification of plants. He 

 finally decided to consider them as plants of a specially 

 primitive type ; some he compared to Myxomycetes, and 

 others were provided with special polysyllabic designations, 

 and consigned to classes or groups instituted for their recep- 

 tion. In some of these structures he recognised a resem- 

 blance to sphserocrystals, but, unfortunately, the temptation 



1 Dawson (1), p. 638. 



