80 SECTIONAL ADDRESSES 
During the filling of the Coal Measure geosyncline, local folds of the 
Pennine family were lines of delayed settlement, and it seems unlikely 
that the Midland Province area was then being compressed. Moreover, 
within this area the flanks and crests and troughs of the folds affecting 
Carboniferous rocks are broken by normal faults of extension, whose 
‘ wants’ or ‘ barren areas’ go far to compensate the shortening of the 
base line required for maintenance of continuous cover for the folds. 
From mining records we have indications that certain longitudinal faults 
had cracked and suffered adjustment as the Coal Measures were deposited, 
but the main displacement of all coalfield faults belongs to the time of 
Hercynian uplift, after the accumulation of the Upper Coal Measure 
Red Beds, and before the planation which made ready for the deposition 
of the Permian. 
By pattern and by distribution over all the area studied, Pennine and 
older and newer faults and folds are so closely associated that it is 
inconceivable that they should have come into existence or developed 
separately. Lateral compression does not explain the existence of 
normal faults along the middle limbs of folds, nor the characteristic 
back-step adjustments in the pitch of troughs ; and by stages Pennine 
structures must have been both tensional and compressional. Only by 
meticulous measurement of the extent of wants and barren areas in 
disrupted sheets of sediment which were once continuous, such as coal 
seams, could the relative importance of positive and negative strains be 
evaluated. It is in the hope that geologists interested in such problems 
will seek out and compute the exact geometrical information available 
in coalfield mine plans, that I have stressed their interest in the opening 
remarks of this address. 
