Wasmtiih on the (Pittsburg Coal (Bed. 
273 
dividing into pannels the extension on the rise, and from the 
latter the rooms E E E for coal mining are turned off. 
The jDarticular 
feature of the coal 
bed in this district 
is its distinct and 
regular cleavage, 
thus promoting min- 
ing of lump coal; 
the faces of the main 
slips are the faces of 
the rooms. 
The distance 
from the shaft to 
the most inside faces 
of the main entries 
is about one mile. An output of 1000 tons of screened coal per 
day of ten working hours can be furnished without any force 
on account of the most perfect working order of all details 
concerned. 
In extending the mine workings it has been developed, that 
the northern flexure of the synclinal referred to, rises at an 
average of i to 3 per cent, or hardly 1 % degrees; but the flank 
of the basin consists really of a combination of numerous, very 
gentle dipping rolls or synclinals and anticlinals, K K K, fig. i, in 
both directions, strike and dip. The anticlinals are called 
"hills" and the synclinals "swamps" and both are accompanied 
by numerous disconnections and dislocations of the coal bed and 
its country rock (roof and floor), but in accordance with the 
very gentle dip of the hills and swamps the dislocation mostly 
is trifling, exceptionally from i to 1 1^ feet vertical. The dis- 
connection of the coal bed and roof work is complete and dis- 
tinct, the original projections of fracturing being rubbed smooth 
by continued sinking of one part of the measures or by dispro- 
portionately sliding of both parts of the measures. The discon- 
nections and dislocations indicated H H H, fig. i, generally are 
termed "clay veins," "spars," "slack veins." The courses of 
the clay veins differ, thus crossing each other, and the same 
clay vein might be cut in several entries and rooms. These 
