602 Faults and Denudations. 



South Stafford, North Stafford, Cheshire, Lancashire, 

 and the North Wales coalfields, are still probably one 

 or almost one coalfield, only great parts of them are 

 buried and. concealed deep under Permian and New 

 Red strata, in some places several thousand feet deep. 



Thus it sometimes happens, by a combination of 

 the curvature of strata and faults, that only by a series 

 of geological accidents have the Coal-measures been 

 brought to the surface and exposed to view. We may 

 take the South Staffordshire coalfield as an example, 

 where the New Red Sandstone and Permian rocks are 

 thrown down against the coalfield on both sides. 

 Originally, before these faults took place, the New Red 

 Sandstone and other rocks spread entirely over the 

 surface. The New Red Sandstone and Marl, where 

 thickest, are more than 2,000 feet thick ; above it lies 

 the Lias, 900 to 1 ,500 feet thick ; then comes the 

 Oolites, and lastly, all the Cretaceous strata. This 

 enormous mass of superincumbent strata, once lying 

 above the South Staffordshire Coal-measures, was after- 

 wards dislocated by faults, which brought the lower 

 Permian and New Red portions of them down against 

 the sides of the present coalfield. A vast denudation 

 ensued, whereby many of the formations nearest the 

 surface were removed, and the whole country was worn 

 down to one comparatively general level. It is by such 

 processes that some of our large and productive coal- 

 fields have been exposed at the surface. Hence we now 

 find a great manufacturing population all centred in 

 areas (like those of South Staffordshire, Warwickshire, 

 and Ashby-de-la-Zouch) which might never have been 

 known to contain coalfields, had it not been for the 

 geological accidents of those faults and denudations 

 which I have explained. 



