STEVENSON, COAL BASIN OF DECAZEVILLE, FRANCE 255 



mont, the "decouverte noiivelle," recently opened by the Decazeville 

 company. This great excavation is at the summit of a narrow ridge and 

 opens to both north and south. 



The road southward from Decazeville to Tramont passes the grande 

 decouverte on the Bourran bed, the Bourran shaft on the same bed, as 

 well as the broad expanse on which the Decazeville company roasts the 

 blackband ore. Where the road turns eastward at somewhat more than 

 a mile from Decazeville, an exposure of sandstone and conglomerate, be- 

 longing to the Campagnac system, dips westwardly at 25 to 30 degrees, 

 and a similar dip is shown at another exposure beyond. The Campagnac 

 coal bed has been mined for a long time along the west face of the ridge 

 at about 250 feet above Decazeville, and work is still carried on in some 

 of the openings. The last dip observed in coming up the hill is westward, 

 but at the first pit reached, the dip is eastward at 55 degrees, so that a 

 sharp fold has been crossed within 500 feet. At that pit, the coal under- 

 lies a coarse conglomerate, but at the entrance to the decouverte, 100 

 yards beyond, the coal is covered by five to six feet of clay shale. The 

 short through cutting which leads into the decouverte shows the coal 

 greatly disturbed, and a complex fold is displayed on the westerly wall 

 within the quarry. As the longer axis of the decouverte crosses the fold 

 diagonally, a good section of the coal is exposed in the easterly wall, 

 where disturbances are of limited vertical extent. The following meas- 

 urements are approximately correct, as they are almost vertical to the 

 bedding. The order is descending : 



Feet Inches 



1. Conglomerate 



2. Coal and shale; very irregular owing to erosion during 



deposition of the overlying rock ; coal and shale 

 layers are very distinct ; but films of coal pass down- 

 ward into the underlying shale as irregular wedges. 



4 feet to 8 



3. Clay shale ; this also has been removed in places ; it 



contains numerous plant impressions with films and 



lenses of coal, as well as some ironstone 5 



4. Coal, 3 to 4 inches, black shale, 6 to 8 inches 10 



5. Clay shale, somewhat contorted, contains streaks of 



coal, some of which come from below and extend for 



a foot or more across the laminae 3 7 



6. Coal, with regular roof, many thin partings, of ap- 



parently mineral charcoal 4 6 



7. Coal and argillaceous sandstone; 7 layers of coal and 



5 of sandstone. In some places, the coal layers be- 

 come thin and the mass is mostly sandstone, while 

 in others the upper sandstones disappear and the 

 coal layers become continuous with the overlying 



