Mr. F. Forster's Observations on the Soutli Welsh Coal Basin. 113 



the Welsh collieries, is veiy trifling, as compared M'ith the Durham and 

 Northumberland districts ; this may, in some degree, arise from the 

 greater inclination of the strata allowing the Gas to find its way to the 

 surface between the planes of the different beds ; that it cannot be al- 

 together attributed to the great inferiority of the Welsh Coals, for the 

 artificial production of Gas is evident, from the remarkable fact that the 

 Stone Coal Seams generally abound more in Fire Damp than the seams 

 of Bituminous Coal. 



OBSERVATIONS ON THE QUANTITY OF COAL CONTAINED IN 



THE MINERAL BASIN. 



To estimate correctly the quantity of workable Coal contained in this 

 district, is rendered extremely difficult by the position of the strata, for, 

 owing to the high angle at which they are, generally speaking, inclined, 

 the greatest proportion of the lower range of seams, in the centre of the 

 Basin, will lie at a depth which our present knowledge of mining has 

 taught us to look upon as inapproachable. The available proportion of 

 any seam or class of seams also varies according to the angle of inclina- 

 tion, which, as has before been stated, varies in every part of the Basin. 



The lowest range of seams, for instance, which are about 60 feet in 

 aggregate thickness, will occupy an area of about 700 square miles, and 

 would yield (did their depth not exceed 200 fathoms, and at a moderate 

 angle of inclination) upwards of thirty thousand millions of tons of Coal ; 

 yet, it is very probable, that not more than one-third of that quantity 

 will ever be obtained from them. The upper seams, on the other hand, 

 while they occupy a much less surface of country, are capable of being 

 worked to a greater extent from the crop or out-break of each seam, 

 owing to their lesser degree of inclination and the more moderate depth 

 they attain. Near the eastern termination of the Basin, however, the 

 great elevation of the country, and the regularity and flatness of the 

 strata, render available a much greater proportion of the Coal. Under 

 all these circumstances, it may be estimated, as an approximation, that the 

 quantity of workable Coal does not exceed sixteen thousand millions of 

 tons. 



VOL. I. Q 



