STEVENSON, COAL BASIN OF DECAZEVILLE, FRANCE 269 



underlying the main coal. Beyond that is a broad valley, rising rapidly 

 and marking the place of the old decouverte, whence the coal was taken 

 prior to the consolidation of the Commentry and Decazeville companies. 

 The direction of these old workings is indicated by a white space covered 

 with ashes and by the fumes which rise in such dense clouds that the hill 

 is known as the "montagne-qui-brule." An immense quantity of coal 

 was removed from this old decouverte, where owing to rapid develop- 

 ment of the fold the bed was reached with minimum of stripping. But 

 the crush was very great, and the coal must have been much more broken 

 than in the present workings. The systematic methods pursued by the 

 director, M. Antoine Jardel, have led to securing coal much less injured 

 and to reducing very greatly the loss by fire. 



The coal in the southerly wall is no longer recognizable above the 

 twelfth bench ; but before the great destruction by fire, the face of coal 

 shown along the fold must have been at least 250 feet high and more 

 than 300 feet wide at the bottom, fully deserving the name, "mountain 

 of coal." The bizarre arrangement in the wall, which is not well shown 

 in the defective photograph, is that of the underlying clay; the great 

 coal was exposed on both sides. This clay enables one to recognize the 

 rapidity with which this fold, like the others already mentioned, de- 

 creases toward the north. In the southerly wall, one of the lower clays 

 is squeezed into a carina on the eleventh bench; but, midway in the 

 excavation at the level of the third bench, the highest of the clays folds 

 over the anticline, a fall of 130 feet in barely 300. The exposures in 

 the wall are very good and illustrate well the manner in which the read- 

 ily yielding clays were divided and pushed into spaces between blocks of 

 more rigid materials. 



The coal is traceable on the twelfth as well as on the eleventh bench, 

 but in great part it has been baked so as to be worthless. A fine expo- 

 sure on the eleventh consists almost wholly of beautifully compact an- 

 thracite with no macroscopic evidence of porosity. This proves that, 

 under proper conditions of pressure, bituminous coal can be converted 

 into anthracite within a brief period by slow distillation alone. On the 

 lower benches, beyond the influence of the fire, there are many illustra- 

 tions showing the effect of pressure on structure. The shales vary ac- 

 cording to composition; the harder, coarser beds have been folded so as 

 to show long curved faces, often along the bedding, while the finer, more 

 argillaceous beds have been squeezed into wrinkles, sometimes vertical to 

 the bedding, sometimes parallel ; while in many cases they have been 

 crushed into lenses, polished so as to resemble talcose schist. 



