I9II-] STEVENSOX— FORMATION OF COAL BEDS. 89 



ulmic materials. The Autun boghead, 24 to 25 cm. thick, is not an 

 accumulation of resinous pellets clue to injection of hydrocarbons 

 into plant debris, but it consists of 1,600 to 1,800 beds of algse, which 

 sank to the bottom along with grains of pollen and the fundamental 

 material as well as the detritus. The fundamental material is brown, 

 rather flocculent and feebly colored. It is a precipitated brown 

 substance analogous to the ulmic matters which color the Amazon 

 and certain of its affluents. It contains particles of a darker mate- 

 rial, thelotite. an infiltration which penetrates the thalli. 



The Pilas were alg?e of very low type. Their isolation in the 

 fundamental material, their accumulation in beds, with traces of 

 pressure on the under surfaces, suggest that they were floating algae 

 like the flours d'caii. The pollen grains, usually reduced to their 

 coats, were a powder resting on the water with the flcurs d'cau. 

 The accumulation, which may have been very rapid, was only an 

 incident in the formation of bituminous shale. It was made in 

 quiet waters, with little or no current, and so rapidly that putrefac- 

 tion could not begin in the mass. The deposit was laid down prob- 

 ably in shallow brown waters, like those of the Amazon region, 

 whose acidity is unfavorable to development of many bacteria. 

 Nearby, were forests of Cordaitcs, which furnished the pollen. 



The second paper by the same authors**' gives results of study 

 of the so-called kerosene shale of Xew South Wales, which had 

 been utilized as a source of gas and illuminating oil. This shale, 

 known as Hartley mineral, Wollogongite and, in some reports as 

 Torbanite, is of uncertain occurrence. [Mackenzie''^ says that the 

 deposits are very irregular, there being no guide to discovery except 

 the presence of fragments at or below the outcrop. Toward the 

 border of a mass, the rich mineral becomes deteriorated and grad- 

 ually passes into indurated clay, bituminous or non-bituminous shale, 

 coal or ironstone. It occurs at two horizons in the Permo-Carbo- 

 niferous of New South Wales, the most notable deposits being in 

 the Upper Coal Aleasures, including the well-known areas of Hart- 



" C. Eg. Bertrand et B. Renault. " Reinschia australis et premieres re- 

 marques sur le kerosene shale de la Nouvelle-Galles du Sud," Bull. Soc. Hist. 

 Nat. d'Aufun, VI., 1893. Separate, pp. 105, pi. 7. 



** J. ^Mackenzie, Ann. Rep. Dept. of Mines for 1896, p. 100. 



89 



