30 



tistics for the year 1855," when the get of argillaceous iron-stone was 1,165,500 

 tons, it has been yearly diminishing until in 1868 it was but 628,845 tons, the 

 deficiency for the ironworks being drawn from other British and foreign mines. 



There are other iron mines, brown htematites, worked at Pentjrrch, Wen- 

 voe and'Mwyndy, near Llantrissaint, probably of the Permian age, and 

 infilling hollows and fissures of the mountain limestone. 



The first record of the produce of the mines is by Mr. Hunt : in 1857, 

 24,300 tons ; in 1868, 83,835 tons ; in 1871, 83,324 tons. 



The Mwyndy mines were worked and smelted on the spot in the time of 

 Henry VIII., and mentioned by Leland in his " Itinerary." 



The pig iron made in South Wales, given in the Edinbunih Philosophical 

 Journal, was in the year 1827, 272,000 tons ; some other source, 1839, 453,880 

 tons ; Mr. Eobert Hunt, 1854, 750,000 tons ; 1859, 985,290 tons ; 1868, 894,255 

 tons ; 1869, 839,.502 tons: pig iron, 1870, 979,193 tons; 1871, 1,045,916 tons. 



Coals raised : Mr. Eobert Hunt, in the year 1854, 8,500,000 tons ; 1868, 

 13,210,000 tons ; 1869, 1.3,454,800 tons ; 1870, 13,664,192 tons ; 1871, 14,035,525 

 tons. 



Great as the quantity of coal comprised within this field, yet it has been wisely 

 ordained by Him who hath done all things weU, that the valuable mineral by 

 the deeply denuded valleys intersecting the field, some of them 800 and 1,000 

 feet deep, together with anticlinal lines and faults, have placed two-thirds of 

 the coals, or that portion between the eastern outcrop at Pontypool and 

 Blaenavon and the Vale of Neath, so that the lowest seam can be won by pits 

 of less than 1,000 yards in depth. 



West of the Vale of Neath, and on to LlaneUy, in the deepest part of the 

 basin, a greater depth ^vill be required to reach the lower seam, but what 

 depth I am not prepared to state ; yet the day must be very distant when 

 that will be found necessary. 



The dip along the north outcrop is very moderate, ranging from 3 to 6, 

 and in some cases 9 inches per yard ; while on the south crop it varies from 

 9 to 12, 15, and 18 inches per yard, this gradually flattening northwards 

 leaving a large area in the centre of the field comparatively fiat, excepting 

 where the anticlinal line disturbs the stratification, and even adjoining that 

 the dips vary very much. 



Faults : The most numerous in the field run from north-west to south- 

 east, and vary in amount of vertical displacement up to 250 to .300 yards ; 

 others running in an east and west direction, the amount of displacement being 

 in some places from 400 to 500 yards. 



The greatest fault I have heard of in the field is one in Pembrokeshire 

 which, in 1841, the late Mr. D. H. Williams, one of the officers of the 

 Ordnance Geological Siu-vey, wrote to me and described as being equal to 

 2,000 feet, or 666§ yards. 



The deepest pits now sxink are The Abercame (Ebbw Valley) Ebbw Vale 

 Company, 304 yards ; New Tredegar (Rhymney Valley) Powell's Duffryn 



