544 DRAINAGE OF COAL MINES. 
held together, represent the clay and rubbish 
that fill the Faults, and form the partition walls 
that insulate these adjacent portions of strata, 
which were originally formed, like the sheet of 
Ice, in one continuous plane. Thus, each sheet 
or inclined table of Coal measures, is inclosed by 
a system of more or less vertical walls of broken 
clay, derived from its argillaceous shale beds, at 
the moment in which the Fracture and Disloca- 
tion took place ; and hence have resulted those 
joints and separations, which, though they oc- 
casionally interrupt at inconvenient positions, 
and cut off suddenly the progress of the collier, 
and often shatter those portions of the strata that 
are in immediate contact with them, yet are in the 
main his greatest safeguard, and are indeed es- 
sential to his operations.* 
These same Faults also, whilst they prevent 
the Water from flowing in excessive quantities in 
* " If a field of coal (says Mr. Buddie) abounding- in water, 
was not intersected with slip Dykes, the working of it might be 
impracticable, as the whole body of water which it might contain 
would flow uninterruptedly into any opening which might be 
made into it ; these Faults operate as Coffer Dams, and separate 
the field of coal into districts." — Letter from Mr. John Buddie, 
an etii'ment Engineer and exyerienced Coal Viewer at New- 
castle, to Prof. Buckland, Nov. 30, 1831. 
In working a Coal Pit, the Miner studiously avoids coming 
near a Fault, knowing that if he should penetrate this natural 
barrier, the Water from the other side will often burst in, and 
inundate the works he is conducting on the dry side of it. 
A shaft was begun about the year 1825 atGosforth, near New- 
