344 Mr . Martin’s Description of the Mineral Bason 
all those which do not lie above 5 or 6 00 fathoms in Glamor- 
ganshire and Carmarthenshire have not reached this county, 
by reason of the bason not being of sufficient depth and width 
to hold them. 
7. The strata of coal at the east end of the bason running 
from Pontypool to Blaenafon and Clydach, and on the north 
side from thence to Nanty Glo, Ebbw, Beaufort, Sirhowy, 
Tredegar, Romney, Dowlais, Penderryn, Plymouth, Cyfarthfa, 
Abernant, Aberdare and Hurwain Furnaces and Iron Works, 
are of a cokeing quality, and from thence the whole strata of 
coal to St. Bride’s Bay alter in their quality, to what is called 
Stone Coal, (the large of which has hitherto been used for 
the purposes of drying malt and hops, and the small, which 
is called Culm, for burning of limestone ); the several strata 
of coal from Pontypool, on the south side of the bason, 
through Risca, Llantrissent, Margam, and Cline Wood, to 
Burry River, Llanelly, and the south side of Pembrey Hill, are 
principally of a bituminous or binding quality. 
8. Notwithstanding the principal strata of coal in Glamor- 
ganshire, lie from 5 fathoms to 6 or 700 fathoms deep, still 
it has not been necessary to pursue these strata deeper than 
about 80 fathoms. 
9. The veins of coal and iron ore, in the vicinity of most 
of the iron works in Monmouthshire and Glamorganshire 
are drained and worked by levels or horizontal drifts, which 
opportunity is given by the deep valleys which generally run 
in a north and south direction, intersecting the range of coal 
and iron ore, which run in an east and west direction, under 
the high mountains, and thereby serving as main drains, so 
that the collier or miner here gets at the treasures of the 
