Our Coalfields: Present and Future Prospects. 559 
some places exactly, at others approximately, the shape of the pre- 
Coal-measure floor and the outcrops of its constituent formations; 
and to disentangle, in part, the pre- and post-Coal-measure move- 
ments. Thus we get additional evidence to show that before Middle 
Coal-measure time, denuded folds, with a north-west or Charnian 
trend, and other folds with a north-east or Caledonian trend 
prevailed. The post-Carboniferous and pre-Permian movements 
emphasized and enlarged some of these folds. As already remarked, 
a matter of great practical importance is as to how far these pre- 
Coal-measure folds interfered with the continuity of deposition of 
the productive series, with, for example, the original extension of the 
Thick Coal of South Staffordshire. Since Jukes-Browne’s time it 
has been known that the Thick Coal group as a whole thins, and the 
coal itself deteriorates, southward towards the Clent and Lickey 
Hills. It is the discontinuity and local deterioration in an easé and 
west direction, beyond the Boundary Faults, due to pre-Coal-measure 
flexures, and irrespective of post-Carboniferous movement, that I have 
been emphasizing. 
The powerful disturbances of post-Carboniferous and pre-Permian 
age, which have affected all our coalfields, I have no intention of 
discussing here. Professor Stainier, the Belgian geologist, has just 
published a lengthy and able discussion on the subject,’ while the 
lucid account by Dr. Strahan in his Presidential Address in 1904 and 
his recently snmmarized views in a lecture to the Royal Institution 
will be in the minds of all geologists. 
I do not think, however, that it is generally realized what a great 
part the two dominant pre-Carboniferous systems of folding played 
in determining the trend of the post-Carboniferous flexures. In the 
South Pennines, in the Apedale disturbance of North Staffordshire 
and in the Malverns we have nearly north and south folds due to 
a great easterly thrust; but elsewhere in the Midlands and the 
North the movements were taken up, to the west of these north and 
south lines by the Caledonian folds, and to the east by the Charnian 
flexures. It is very instructive to watch in the centre of the South 
Staffordshire Coalfield the old Charnian fold of Silurian rocks that 
make up Dudley Castle Hill, the Wren’s Nest, and Sedgley Hill 
struggling, as it were, against the newer post-Carboniferous easterly 
squeeze, which has impressed a north and south strike upon each of 
the domes, arranging them en échelon from north-west to south-east, 
and incidentally permitting the great laccolitic intrusion of Rowley 
Regis. 
Tt will be found, however, that the vast majority of the folds and 
faults in the Midland and Northern Coalfields are not along what may 
be called strict Hercynian lines—that is, north to south and east to 
west—but along the locally older Caledonian and Charnian directions. 
It was as if the great north and south flexures of the Southern 
Pennines and Malverns, and the east and west Armorican folds of the 
South of England, to a large extent exhausted the mighty attack of 
the Hercynian movements coming from the South and Kast of Europe; 
1 Trans. Inst. Min. Eng., vol. li, pt. i, pp. 99-153, 1916. 
