98 Mr. F. Fobster's Observations on the South Welsh Coal Basin. 



well identified ; but it may still be given as a general character that the 

 north-crop seams are Free-burning Coal, underlaid by others passing 

 into Stone Coal as they approach the Limestone; and the south-crop 

 seams retain their bituminous quality until they approach the eastern 

 termination of the Basin near Pontypool, where, by a diminution in 

 their quantity of bitumen, they become changed into Free-burning 

 Coal. Between the head of the Neath valley and Hirwain, about 25 

 miles from Pontypool, the north-crop seams, by an increase of their 

 proportion of bitumen, are also changed from Stone Coal into Free- 

 burning Coal, which thus becomes the prevailing character of the seams 

 cropping out around the eastern termination of the Basin.* From this 

 circumstance, as well as from the abundance of Iron-stone, alternating 

 with and underlying the lower seams of Coal, added to the flatness 

 and regularity of the strata, this part of the Coal-field has become the 

 site on which the principal Iron works of South Wales are erected, and 

 from which they procure their immense supplies of Coal and Iron Ore. 



Of these varieties, there is by far the greatest available quantity 

 of Stone Coal yet unworked, and, ranging along the elevated ground 

 forming the northern edge of the Basin, a very large proportion of it 

 is attainable by level. 



Of the Free-burning Coal, great quantities have been already, and 

 are daily, consumed by the Iron works in the north-eastern part of the 

 district. An extensive tract, along the centre of the Basin, is yet un- 

 worked ; and it possesses, in common with the Stone Coal, all the 

 advantages arising from its position in the more elevated parts of the 

 district. 



Of the Bituminous Coal there is an immense tract along the southern 

 edge of the Coal-field ; but the great inclination of the strata, and the 

 comparatively low ground, beneath which the bituminous seams extend, 



* Whether the vicinity of the Trap and Transition rocks can, at any remote period, have 

 had a tendency to deprive the Coal of its bitumen, I must leave to those better acquainted 

 with geological phenomena to decide ; but the existence of Stone Coal in every part of 

 this basin which is either underlaid by the Trap, or nearly approached by the Transition rocks, 

 is, to say the least of it, a singular coincidence. An examination of Greenough's (?«o ■ 

 logical Map, together with the above description of the tracts occupied by the different 

 varieties of Coal, will render this fully apparent 



