504 APPENDIX. 



The beds are intersected by three great dykes, called failles 

 in Flanders, crains in France, sprungs or leaps in Germany. 



The first, on the right of the chief hill, is thin towards the 

 summit, but thickens as it deepens. The second is of great 

 thickness, but does not pass the fiftieth layer of coal. The 

 third resembles the first. 



There is a great number of inferior dykes in this hill. 

 Some are 420 feet thick at the depth of the lowest beds j but 

 probably they thicken still more as they approach the radical 

 rock. 



All the beds of coal, which are cut by the dykes, are either 

 lost in them, or continued in little irregular threads ; or are 

 found behind, either above or below their natural directions, 

 and never in a straight line. 



The mass of these dykes is chiefly of rock* ; others of 

 sandstone, of agaz (that is, a ferruginous sandstone) j or of 

 earth, with here and there broken coal. 



Beds of the Hill of St. Gilles, which continue for more 

 than a league. 



1. From the surface to the first bed of coal, 21 feet. (The 



Liege foot is 10 inches French.) 

 Thickness of this bed of coal 15 inches. 



2. Intermediate bed 42 feet. 

 Second bed of coal 1 f. 7 i. 



Divided into two by earth nearly an inch thick. 



3. Intermediate 84/. 



Third bed divided into two, 4 f. 3 i. 



4. Intermediate 49 f. 

 Fourth bed 1 f. 7 i. 



5. Intermediate 4%f. 



Fifth bed 1 f. 3 i. In three layers, 



6. Intermediate 56 f. 

 Sixth bed 7 i. 



* Such is the vague language of Genett^. 



