458 Mr. Horner on the Geology of the Environs of Bonn. 



Ft. In. 



9. Unaltered brown coal or bituminized wood, preserving the woody texture 8 6 



Total thickness of coal 13 feet 8 inches. 



In the lower part of this last bed occur kidney-shaped masses of compact clay 

 iron stone. 



58 10 



Then comes a trachyte tuff, with portions of hard trachyte, into which they 

 had sunk to the depth of two feet. It is here the usual underlier of the 

 hrown-coal beds, but it is also found lying between them, so that it is very 

 possible if the shaft were sunk deeper, that this tuff would be gone through, 

 and other brown-coal beds be found below it. 



M. Von Dechen states* that in the district of Briihl the beds lie con- 

 siderably above the Rhine valley, and this seems to be equally the case on the 

 right bank. It is worked at several places on the right bank, but by far the 

 most considerable mines are on the other side of the river, and in the district 

 immediately around Briihl. The united thickness of the lignite beds in dif- 

 ferent situations in the plateau is very various, often too inconsiderable to 

 be worth working. It has not been ascertained by actual trial whether they 

 stretch quite across the plateau, the mines being situated on the east and 

 west sides, but this is very probably the case. The following table will show 

 the thickness of the brown-coal beds at different points on each side, lying 

 east and west of each other. The thickness includes the clay beds that may 

 be interposed between one layer of brown-coal and another. 



West Side. 



Feet. 



Lieblar From 6 to 66 



Zisselsmaar 16 to 65 



Turnich 10 to 60 



Schlenderhan 1 4 to 40 



East Side. 



Feet. 



Walberberg near Briihl . . . .From 12 to 30 



Metzmacher 26 to 49 



An der Gabgay 43 



Pingsdorf 36^ 



Hennersgrube 40 to 52 



Altstadter Berg 6 to 60 



Gleneler Berg 18 to 70 



Frechemer Berg 19 to 55 



The various mines of brown-coal in the district give occupation to about 

 1200 persons. The coal is consumed almost entirely by the poorer classes, 

 as its strong peculiar odour, and sometimes sulphurous vapours, render its use 

 disagreeable. Some of the harder kinds are used as they are taken from the 

 pit; but these form a small proportion, and are, moreover, not so valuable for 

 fuel : the greatest part is used after it has been artificially prepared. It is 



* Karsten's Archiv, uti svpra, p. 417. 



I 



