THE COAL QTJESTIOK. 



73 



is left as supports and so on. Deductions are made for this, about 

 a third of total amount ; or (40 per cent, sometimes) is deducted 

 by the commissioners. 



The contents of the several coalfields stand thus in the Eeport, 

 Ko bed less than one foot is reckoned. 



In the known coal fields we thus have a total of ninety-thousand- 

 million tons. 



Though the commissioners have calculated all these tons as 

 available, it must be admitted that in some cases a certain 

 proportion is problematical. 



Leaving the details of other coalfields, let us give a little 

 attention to our own Bristol and Somerset Field.*' 



* A map, similar to the diagram exhibited, has been published by 

 Mr. Me Murtrie in the proceedings of the Bath Archaeological and Natural 

 History Field Club. Vol. 2, part 4—1873. 



