6 
other, of any of the same beds, at the two points where the 
disturbances cease, on a North and South magnetic line. I 
shall, therefore, take one of the uppermost beds in the series, 
and one of the lowest — i. e., the Thick coal at Orgrave, on 
the edge of Derbyshire, and the same bed at Elsecar ; and 
the Gannister, or Pecten coal, at Dore Moor, in Derbyshire, 
and the same at Deep Car. Now the fall of level on the 
surface, from Elsecar to Swinton, is 67 feet, or 221 yards, 
and the fall from Orgreave, on the North Midland Railway, 
to Kilnhurst, is not more than forty yards, and probably 
less ; so the difference in point of level can only amount to 
eighteen yards. Again, the Grannister or Pecten coal, at 
Dore Moor, from barometrical observations made l^y me, 
in 1838, is 48 yards above the river Sheaf, at Hunter's Lane 
Bar ; and Deep Car, through which passes the Manchester 
and Sheffield Railway, with a gradient of five yards to the 
mile, being eight miles distant, will give forty yards of ele- 
vation above Sheffield ; so that the difference of elevation 
between the same coal at Dore Moor and at Deep Car, will 
only amount to a few yards. Thus, there is no material 
difference, in level, of the Thick coal, which, in the scale 
of strata, is a higher bed ; and, similarly, in the lowest 
worked bed, the Gannister. There is, therefore, no material 
elevation in the country on the North, above the same beds 
on the South side of the valley of the Don ; the intervening 
disturbances, therefore, are merely local, and have no gene- 
ral effect upon the stratification of the whole country, 
I now proceed to shew that the supposed lateral movement 
is due to a depression of the beds on the South side of the 
Don. The water levels^ on each side of the disturbed dis- 
* A water level is a line at right angles to the steepest inclination of (he coal, 
and is correctly represented by the spouts which carry water in any street ; if 
the roofs of the houses rise due West, the direction of the street will be North 
and South, and the line of spouting, or water level, will be the same. A change 
of direction, therefore, in the water level, merely indicates an azimuthal change 
of the inclination of the coal-bed. 
