432 REMARKS ON THE COAL DISTRICT 
of the faults, the beds of sandstone and the strata 
of black shale were forced vertically upwards. 
Such an abrupt and singular change of the 
position of the strata probably occurred at a very 
remote period of time, when the beds were still 
soft and flexible, and when the strata might have 
been forced into a vertical position in the lines 
of the faults, without materially affecting the 
inclination of the adjacent portions of the coal 
formation. 
Numerous alterations in the position of the 
beds of coal, have been, in ancient times, pro- 
duced by the occurrence of faults; thus, in the 
higher rocks of the carboniferous series, between 
Worsley and the river Irwell, near Manchester, 
the level of the four feet coal mine has been 
repeatedly changed. At Roe Green, near Wors- 
ley, this mine has been removed towards the 
North, by a fault of 400 yards. Between Roe 
Green and Clifton, the direction of the level of 
the mine has been altered, by a fault of 600 
yards, to a South-Easterly direction, tending 
towards the great red rock fault of the valley 
of the Irwell; and on the Eastern side of the 
great Irwell fault, the level of the four feet mine 
has been again removed, so that it is found to be 
