SUBTERRANEAN MOVEMENTS, Sec. 107 
northern system of dislocations is characterized throughout by sudden 
and violent fracture and partial displacement, the southern con- 
sists wholly of steep anticlinal ridges, generally bent into conti- 
nuity over the axis, so as to cause a system of parallel undula- 
tions and contortions for twenty miles in breadth between Colne and 
Lancaster. Its south-westward extension, as indicated by the ranges 
of the Lancashire coal tracts, is about fifty miles ; further prolonged 
it would cross the N. N. W. line of elevation in the vale of Clwydd, 
and nearly coincide with the axis of North Wales. From about 
Burnley proceeds in a direction S. S. E. the great range of dislocation 
which reaches the Peak of Derby and throws off on the east the 
Yorkshire coalfield, and on the west parts of the Lancashii’e and 
Cheshire coal tracts. 
The diagram (No. 14) may be usefully consulted for the rela- 
tion of these various disturbances. 
FAULTS AND MINERAL VEINS. 
We may now proceed to trace the relations of the minor disloca- 
tions included between the great branches of these systems of dis- 
turbance. 
The great area included between the Penine fault and the mag- 
nesia n limestone terrace is not so much disturbed by faults as the 
violent convulsion of its borders might lead us to imagine. The 
mining tracts of Teesdale, Swaledale, Wharfedale, and Greenhow hill, 
are indeed much convulsed, but it is certainly true that we may trace 
for many miles along the slopes of Wensleydale, Garsdale, Coverdale, 
and on the sides of Cam fell, Ingleborough, and Wharnside, particular 
beds of rock not at all disturbed by convulsions. In most cases the 
great dales and lesser valleys appear to have been marked out by 
dislocations specially determining their line, or generally influencing 
the direction of their descent. Professor Sedgwick admits a great fault 
as ranging down Teesdale, Lunedale is on the line of a dislocation, 
p 2 
