76 SECTIONAL ADDRESSES 
the local Carboniferous from the lowest D1 to the zone of A. tenuis has 
been exposed and bevelled off in the sixteen miles between Miller’s 
Dale and Stockport. 
Steep dips in the Manchester corner of the Icahedshilge Coalfield are 
half compensated in the pitch of the broad Cheshire syncline by low- 
hading, north-westerly throw-back faults, which die in the limbs of the 
anticlines on the north and east. ‘The Irwell Valley-Pendleton Fault, 
with a throw of not less than 2,000 ft. under the suburbs of Salford, is 
about the last and the greatest of the slasher system faults. Beyond it, 
with steepness decreasing from I in 3 to 1 in 6 or less, the Lancashire 
outcrop of Productive Measures sweeps westward to Wigan, where, 
across more faults, it elbows south by St. Helens and Prescot, and so 
beneath the Trias and across to Wales. Decrease of dip in Lancashire 
is associated with transgression of Productive Measures by Permian or 
by overlap of ‘Trias on to Millstone Grit towards the west. 
The northward rise of Coal Measures from under the Cheshire Basin 
continues to a height greater than their local thickness, which in the east 
exceeds 8,000 ft. Across the ten miles wide plateau of the Rossendale 
Anticline which ranges east-west from Bacup to Chorley, the beds of 
Millstone Grit are almost flat, and stratigraphically only some 1,000 ft. 
lower than in the neighbouring crest of the Pennines, from which this 
fold is separated by a mile-wide sloping ridge or neck. 
The North Lancashire Coalfield is a triangular downfold only some 
1,500 ft. deep, tucked in between the Rossendale plateau and the Pen- 
nines, and is cut off towards the north-west by the sharp uprise of Millstone 
Grit and Lower Carboniferous, which outcrop in the Forest of Pendle 
and the lowlands of Craven and the Ribble. This shallow downfold 
contains little more than Lower Coal Measures. 
The horseshoe folds of Flintshire lie to the east and alongside the 
upstanding mass of limestone and Lower Palzozoic rocks of Denbigh and 
Snowdonia, much as the folds in Derbyshire flank the east side of the 
limestone massif of the Peak. The most easterly of them through 
Hawarden, rising and falling transversely 2,000 ft. in about three miles, 
is of similar dimensions to the Brimington anticline. By Caergwrle it 
turns into the profound pre-Trias disturbance of the Llanelidan Fault, 
a branch of the Bala Fault which crosses Wales. ‘The Denbighshire part 
of the coalfield is also traversed by a 1,000 ft. fault through the Vale of 
Llangollen, but most of the curving fractures which cut the North Wales 
coalfield into longitudinal strips are mainly effective in stepping back 
steeply-inclined measures as they dip under the Trias of the Cheshire 
Plain. ‘The westerly transgression of the Trias in Lancashire is matched 
south of Chester by the sudden incoming of the Midland type of Upper 
Coal Measures at the line of the Bala Fault. By Wrexham these red beds 
increase in thickness, and, overlapping the Productive Measures against 
pre-Carboniferous rocks of Shropshire, are probably continuous to Staf- 
fordshire and provide a large part of the filling of the southern half of 
the Cheshire Basin. 
Although it adjoins the Cheshire Basin, there is no suggestion that 
North Staffordshire was ever downfolded with it. ‘The utmost that can 
