WHITE GRIT, GRAVEL, AND BAT HOLES. — LEAD MINES. 



279 



the veins will be found to extend further westward towards the eastern flank of the Stapely and 

 Corndon hills. This surmise is at all events warranted in this district by the constant recurrence 

 of vein stuff, where large masses of stratified deposits are contiguous to the chief ridges of intrusive 

 rocks. The Gravel mines lie to the N.N.E. of the Grit, and after having been abandoned for 

 some years are again coming into use. There are here three chief veins, two of which run more 

 or less across the strata, as in the Grit mine ; the third, proceeding from north to south, is only 

 slightly oblique to the main direction of the chain. The last mentioned is called the Roman vein, 

 and is said to have been worked to more than one hundred yards in depth by the Romans, whose 

 mining utensils have been occasionally found in the galleries. A highly inclined band of compact 

 felspar forms the wall or rider, and as this rises conspicuously above the surface it may have led to 

 the first attempts of the ancient adventurers. The works are distinguished from those of modern 

 date by the smallness of the drifts and the avoiding of those knots of hard rock which now give 

 way before gunpowder. This vein hades sharply to the east, and dividing into two branches, 

 passes through sandy schist, dipping N.N.W., which is so hard and micaceous as to resemble 

 certain varieties of mica schist. It contains cubes of iron pyrites and small veins of quartz. 

 The modern works have been sunk to the depth of 212 yards or 112 yards below the Roman 

 galleries, and it is probable that they will now be followed to much greater depths, a steam- 

 engine having been erected 1 . To the N.N.E. of the metalliferous ground of the "Grit" and 

 "Gravel" are the " Bat holes" and "Wood mines." These have been abandoned for some time, 

 but their geological relations are highly instructive. In one of the principal veins, the wall is 

 granular felspar with green earth ; and two contiguous bosses of crystalline greenstone, rising up 

 unconformably through the strata of sandstone and shale, cut off the productive veins. In fact 

 there has not been in this case a sufficient quantity of contiguous sandstone and shale to afford 

 ground for the production of extensive veins, the bosses of greenstone which form part of the 

 nucleus of the ridge of the Nick knolls and Santley Hill, rising up so very near the edge of the 

 little valley. (PI. 32. fig. 2.) This greenstone is highly crystalline, and breaks into rude columns. 

 It throws off the strata to the east and west on each side of the intrusive ridge, and, as noticed on 

 the side of the Wrekin and Caradoc, the sandstone on its western face is converted into quartz 

 rock, and fractured masses of the same adhere to the steep acclivities and summit of the hill. 

 China stone also occurs among these altered beds, some of which are horizontal, others broken, 

 inclined, and vertical. In the deep cuttings to make the new road between this spot and Hope 

 Mill, I found trilobites in the black schist and flag, identical with those of Llandeilo, with one new 

 species of Isotelus, and many shells in the sandstone similar to those of the Caradoc formation. 

 The veins were formerly worked at the Bat holes, but their productive qualities were found little 

 persistent, and it is said that they were always cut out by hard masses of trap 2 . Phenomena like 

 these have been also discovered in the shale on the sides of the intrusive masses of greenstone of 

 the Round Hill, Buckstone, &c, by numerous trials, which, though successful in detecting small 

 metalliferous veins and bunches of ore for short spaces, have been invariably stopped when the 

 works reached the sides of the ridges of massive greenstone (sometimes basaltiform) which rise up 



1 It is probable that an antique pig of lead found in this district, and now in the possession of Mr. More of 

 Linley Hall, was cast by the Romans from lead extracted at this mine. It bears the impress, IMP. ADRIANI. 

 AUG. Its form is shorter and in every respect dissimilar to the shape of modern pigs of lead. 



2 I was informed by persons formerly interested in these works that the veins frequently reappeared on the 

 opposite side of the intruding or sterile rock. 



2 m 2 



