LEAD MINES OF NANT-Y-MOEN. 



367 



galena diverge from the chief mass, to the sides of the rider quartz rock ; and a rich bunch of ore 

 was worked out on its opposite or south-eastern face. 



The red vein is further removed from the rider rock, and has its name from the lead being 

 coated with the hydrate of iron. At the spot where this vein was cut by the comet vein, the ore 

 thickened for a short distance to six feet, much exceeding the average width of this and the other 

 veins. Besides these principal veins there are several cross lodes. 



In one part of the works the ore is found in apparently regular beds, forming thin laminae in a 

 true greywacke grit, composed of small pebbles of quartz and felspar, with a base of black slate. 

 These beds, some of which are metalliferous and others not, have an united thickness of forty to 

 fifty feet, and dip away from the rider rock or the north-west, at an angle of about 25°. Their 

 position is between the red and the comet veins 1 . 



The levels enter the hill about 500 feet above the adjoining valley of the Towy, and the most 

 extensive are from 1000 to 1200 feet in length. These works are effectually drained by an adit, 

 whose mouth is a little above the rivulet at the base of the hill ; and from which is a constant flow 

 of ferruginous water. 



Here, as in the country of Shelve, are remains considered to have been Roman mines, which, 

 having been placed upon the steepest side of the hill, and where the ore probably cropped out, were, 

 it is conceived, worked by water ? (See further observations below, on the Roman mines of Gogo-fau.) 



It is quite evident that mines, situated like those of Nant-y-moen, where vertical shafts or steam- 

 engines are not required, the whole being drained by an adit, must always be of high value, and 

 accordingly I found the works in full activity in 1833, a period when, from the low price of lead, 

 so many mines had necessarily been abandoned. 



The ore of Nant-y-moen is for the most part of excellent quality, the varieties called " potter's 

 ore" and "steel ore" being abundant, as well as "small ore," a mixture of the two former. 



Roman Mines of Gogo-fau. 



About ten miles west of Llandovery, on the right of the road to Llampeter, occurs 

 one of those elliptical, quartzose masses, so frequent in the "Cambrian System," of nearly 

 half a mile in length, trending from north-east to south-west like all the associated 

 strata. It is called Gogo-fau, or " the Caves," the hill being perforated in many direc- 

 tions by horizontal galleries, considered to have been the work of the Romans. That 

 these galleries were mines, there can be no doubt, since they follow precisely the course 

 of the veins. That they were the work of the Romans is certain ; for they have not 

 been used during the period of modern history, and the galleries are much too long, 

 wide, high and deep, to have been the work of the ancient Britons. This opinion has 

 been recently confirmed by Mr. Jones of Dolecothi, who has discovered the remains 

 of baths, medals, gold ornaments, implements, inscriptions, Roman tiles, &c, thus 



1 This is one of the few examples in England of mineral veins putting on a stratified character, by running 

 for a certain distance parallel to the true beds of the matrix. Similar veins are seen on a great scale in the 

 lead mines of Bleiberg in Carinthia. 



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