191 1.] STEVEXSOX— FORMATION OF COAL BEDS. 5 



fortified by a wealth of mathematical proof which, apparently, 

 leaves little to be desired. 



Scheuchzer'^ described a deposit of black slate in the canton 

 of Glarus, occurring in layers, one third of an inch thick, each 

 consisting of a hard upper and a soft lower lamina. The phenomena 

 observed in the quarry led him to assert "This is now certain that 

 all rock beds were formed by precipitation, through subsidence of 

 heavier earthy particles in a fluid menstruum, especially the waters 

 of the Deluge. The observed difference of materials in every 

 layer as well as the orderly parallelism of the layers is a sufficient 

 proof of this. ... At times all sorts of relics of the Deluge, fish 

 and vegetables occur in these shales." Scheuchzer saw in the coal 

 merely the remains of wood swept oft" during the deluge, " Where- 

 fore here and there stone coals are found which were true wood " ; 

 and he notes the existence of deposits at i8 to 24 yards below the 

 surface. This is his " Lignum fossile ex Sylva submersa." 



De Jussieu,* about 1740, observed, near St. Chaumond in France, 

 many impressions of plants very different from those now existing. 

 He remarked that these represent true plants and that they lie flat 

 as in a herbarium. In seeking their origin he was led to believe that 

 they were vegetation of a warm climate and that they had been 

 transported. The sea covered the continents ; the currents carried 

 and deposited the plants and shells which are found petrified. 



Few writers prior to the middle of the eighteenth century 

 dealt in other than a priori arguments but, after half the century 

 had passed, there came numerous observers whose labors were 

 utilized by Buft'on. 



Buffon^ recognized the vegetable origin of coal and asserted that 

 its excellent quality is due to the intimate mingling of vegetable 

 matter with bitumen — the latter being only vegetable oil or animal 

 fat impregnated with acid. He designates coal as " Charbon de 



^ J. J. Scheuchzer, " Aleteorologia et oryctologia helvetica," Zurich, 1718, 

 pp. no, III, 239, 240. 



■'A. de Jussieu, cited from Saporta by L. Lesquereux, 2d Geol. Survey of 

 Penn., Ann. Rep. for 1885, p. 95. 



'^ L. de Buffon, " Histoire naturelle, generale et particuliere," Sonnini 

 Ed., T. Qme., Paris, An IX., pp. 11, 14, 16, 35, 36, 42-46. The original pubHca- 

 tion was in 1778. 



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