74 SECTIONAL ADDRESSES 
Carboniferous floor of the Midlands has located faults of lateral shift, 
but details await attention, and the subject is too large for further 
discussion here. 
COALFIELD DIMENSIONS. 
In the foregoing description and discussion of structural pattern, 
reference to size has intentionally been omitted. In coalfield engineering 
size is the prime factor controlling development, so, for the better applica- 
tion of the principles which have emerged in the qualitative analysis, 
I shall conclude with notes on the dimensions of those structures in and 
about the several coalfields of the province which have been proved, or are 
likely to prove, important in industrial planning and development. 
The largest and most productive of British coalfields is that of Yorkshire, 
Derbyshire and Nottinghamshire, the East Pennine or East Midland 
Coalfield, a continuous complex downfold or synclinorium, more than 
seventy miles long between Bradford and Nottingham, and forty miles 
wide along the river Don. Half or more than half of its total area to 
and beyond the rivers Ouse and Trent is buried under Permian and Trias ; 
and there, though folds and fault belts from the exposed area can be pro- 
jected, real knowledge of pre-Permian structure has only come with mining 
exploration and development. Denudation had taken toll of all the up- 
raised anticlines before the Magnesian Limestone was deposited, and so 
between Leeds and Nottingham the Basal Permian rests in turn on each 
and every member of the Productive Coal Measures series. 
The Yorkshire Coalfield north of the Don is a comparatively simple 
dish structure, cracked and broken by its faults. Its deepest part is the 
Frickley trough between Pontefract and Doncaster, where the floor of 
lowest Coal Measures lies 4,500 ft. deep twenty miles in from outcrop. 
Towards the south the broad swell of the Don anticline ends in the 
1,500 ft. deep descent to the Maltby Basin, whose slope is broken en 
echelon by the north-easterly Don Faults. Between Doncaster and 
Worksop the central part of this South Yorkshire Basin includes a patch 
of Upper Coal Measures, and here, with 5,000 ft. of Productive Coal 
Measures, is probably the deepest part of any coalfield east of the Pennines. 
Despite truncation at the Permian unconformity, some Productive Coal 
Measures extend for several miles beyond the Trent. 
Contrasting sharply with Yorkshire, where faults are the main dis- 
turbers of continuous mining development, Derbyshire is characterised 
by steep-sided folds of variable pitch, which undulate the measures in 
troughs and arches, nearly, but not quite, high enough to obscure the 
synclinal structure of the coalfield as a whole. From the suburbs of 
Sheffield, the Ridgeway-Renishaw anticline, 1,000 ft. high, pitches 
south-eastwards and bulges the Silkstone Coal outcrop some six miles 
east, and continues by Barlborough and Whitwell underneath the Dukeries. 
Four miles to the south, it has for neighbour the curving hogsback of the 
Brimington anticline, which for eight miles between Holmesfield and 
Duckmanton maintains an even crest level, while the syncline of Dronfield, 
Staveley and Bolsover, pitching with undulations, descends 2,000, ft. 
alongside the steep east-facing flank which at Brimington rises 1,000 ft. 
