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ILLUSTRATIONS OF 
places are 60 feet below the surface of the earth, 
forming a tunnel for a subterraneous navigation^ and 
immense buttresses of limestone are left to support 
the excavations. 
In connection with the coal strata are the subordi- 
nate beds of ironstone, the proximity of which to the 
limestone and coal is so important a feature in the 
mineralogy of the district. It is this which gives 
such an impetus to the industry of the manufacturer, 
for without the lime to act as a flux, and the coal to 
be employed in the various operations of the furnace, 
the ironstone would be comparatively useless.^ "What 
advantage, indeed," observes Dr. Booker, " would be 
derived from living in a land ' whose stones are iron,' 
were coals and lime not also deposited near, to flux 
the stubborn ore? The disappearance of vegetable 
fuel from the neighbourhood, — plentiful as it was in 
its chaces and woods some centuries ago, proves that 
could not have been the material intended by Divine 
Providence for the purpose : and even were it as 
plentiful now as formerly, inadequate would it be 
to furnish a supply for between 80 and 90 devouring 
furnaces ; which at the present time, like so many 
fiery beacons, emit their volumes of flame and smoke 
within seven miles of Dudley Castle. The term 
devouring will not be deemed too strong, when it is 
known that the average consumption of coal by each 
furnace is not less than 160 tons per week; which. 
^ The average quantities of coal, ironstone, and limestone, required to make one 
ton of pig iron, are, of the former, four tons, of the second between three and four 
tons, and of the third one ton. Dr, Booker s Account of Dudley, 
