94 Proceedings of the Royal Physical Society. 



over and under conterminous strata, which abounds in faults 

 often of a very perplexing kind. 



The author, in describing the boundaries of the Bristol, other- 

 wise the Gloucestershire and Somersetshire coalfield, stated 

 that it comprised an area of 338 square miles, which included 

 150 in Somerset, and the Radstock portion of Somerset, 

 commonly called the Eadstock coal basin, of 45 square miles. 



The Report of the Eoyal Coal Commission, drawn up by 

 Professor Prestwich, estimates the Bristol coalfield at 6104 

 millions of tons of coal, calculated to last for upwards of 4000 

 years at an actual '* consumpt " per annum of 1,000,000 tons. 

 This should tend somewhat to allay the fears of alarmists. 



The portion of this great coalfield which Mr Grieve more 

 particularly described was the Eadstock basin above referred 

 to. He spoke of its stratigraphical arrangement, and men- 

 tioned that the thickness of the coal measures here are esti- 

 mated at 8000 feet. There are three series of coal — the 

 upper, second, and lower. The coal rests in the upper series 

 (which Mr Grieve only examined) on a base of mountain 

 limestone, and is overlaid by the inferior oolite, lias, new red 

 sandstone, magnesian conglomerate, and lower new red sand- 

 stone — these strata in a descending scale, and all which require 

 to be pierced before the coal can be reached. The seams of coal 

 vary from fourteen to thirty inches in thickness. Mr Grieve 

 gave, further, some statistical particulars — for instance, as to 

 depth of pit workings (averaging one hundred and forty-five 

 fathoms), output of coal (exceeding 600,000 tons annually), 

 described the old and new methods of working coal in this 

 district.* A singularity peculiar to the old and very clumsy 

 method may be noticed. The pit mouths and shafts generally 

 till within the last twenty-five years or so were only four and 

 a half feet in diameter, and the miners attached themselves by 

 hooks to the pit chain, one over the other, in parties of ten or 

 twelve, sticking together like so many onions on a string, and 

 were thus lowered and raised through this narrow hole (often 

 over a thousand feet deep), showing how much habit can render 

 one callous to a sense of danger. An account was then given 



* The present method being wliat is known to miners as tlie " longwall 

 system." 



