STATISTICS OF THE UNITED laXGDOM. 



453 



levelling agency of denudation has planed off all the inequalities of the surface, 

 until there remained only the coal basins, such as we see them at the present day. 

 Still these coal basins have an area of 12,000 square miles, and they are the most 

 important in Europe, and those which are utilised to the greatest ad vanta o-e. 

 They have been worked at least since the age of the Romans, for cinders of coal 

 have been found on the hearthstones of Uriconium, and galleries of an anterior 



Fi's-. 224.— Coal Basixs. 



IS'on-caibonuerous. 



(-'onl Ij.isiiis. 



date to the Saxon invasion have been discovered in the mines of Wigan. In 1670 

 the English coal mines already supplied more than 2,000,000 tons of fuel a year ;* 

 a century later triple that amount was extracted from them ; and still another 

 century nearer our own days, in 1870, they yielded 110,000,000 tons. The 

 quantity of coal annually raised since then has averaged 125,000,000 tons, worth 



Thomas Wright; Edward Hull, 'The Coilfields of Great Britain." 



