THE MODE OF ORIGIN OF COAL 



221 



Australia. Here all the spores have collapsed and have rough 

 alveolar exteriors. A remarkable feature of oilshales is the very 

 large amount of spore material present in them, a condition cor- 

 related directly with their rich petroleum content when subjected 

 to distillation. A curious error of interpretation has been made 

 in regard to oilshales, bogheads, or bituminous schists, as they 

 have been variously termed. Their structural elements have 

 been regarded by Renault, Bertrand, and Potonie as the remains 

 of delicate gelatinous algae. The present writer, by the improved 

 methods already referred to, has secured evidence that the struc- 

 tures in question are the very 

 rough spores of extinct fernlike 

 cryptogams.^ It is clear, further, 

 that they cannot be anything of 

 so delicate a nature as algae, 

 since highly modified wood is 

 frequently found in the same 

 matrix with them. It is obvi- 

 ous that gelatinous algae would 

 have quickly been obHterated 

 by influences so powerful as to 

 eliminate the structural organi- 

 zation of wood. 



Fig. 3 shows the organization of Kentucky cannel. Scattered 

 throughout the matrix are light bodies which are yellow in the 

 coal itself. These represent spores. They are inclosed in a darker 

 matrix which in some cases reveals lighter, somewhat undulating 

 or crinkled bands or particles. These structures are brown in 

 color in the coal and represent the remains of wood. A large 

 stripe of this kind runs nearly across the illustration. Cannel owes 

 its highly bituminous character to the presence of large quantities 

 of spores, just as is the case with oilshales and tasmanite. Since 

 the spore material is less pure than in the former types of coals, 

 the bituminous matter is less and the distillate of petroleum is 

 correspondingly reduced in amount. 



^ "The Nature of Some Supposed Algal Coals," Am. Acad. Arts and Sci., XLVI 

 (December, 1910). 



Fig. 3 



