VEIN OF COPPER ORE IN ALTERED CAMBRIAN ROCKS. 



261 



altered strata, there are several outbursts of crystalline greenstone, both on the east and west sides 

 of Ratlinghope, similar in composition to some of the varieties described in the eastern slopes 

 of the Longmynd. On the lower side of the hill called Belmont, a fine-grained variety is exten- 

 sively quarried for building purposes, for which it is better calculated than any of the indurated and 

 intractable slaty sandstones of this district. 



The highly inclined and dislocated strata of purple schist and sandstone, which lie between these 

 protruding bosses of trap, are starred through in many directions by veins of white crystallized 

 quartz, which include fragments of the slate and sandstone, the surfaces of the cavities and 

 strings being frequently covered with thin films of grey and green carbonates of copper. These, 

 copper veins, commencing to the north of Ratlinghope, are common to the south- south-west as far 

 as Medlicott, where ore has been extracted by the Snailbatch company. Mr. Hawkins, of Ratling- 

 hope, has made trials near that village, but when I visited the spot, he had succeeded in discovering 

 only disseminated coatings and irregular strings of ore. 



As similar strings, veins, and nests, containing copper ore, and sometimes accompanied by 

 anthracrite and bitumen, have been found at intervals all along the western side of the Long- 

 mynd, even in the similarly composed hills of Lyth near Shrewsbury, it is interesting to detect 

 them also at Ratlinghope and Medlicott, equally associated with and inclosed between rocks of 

 igneous origin. 



In fact the whole of the wide tract included between the Longmynd and the Stiper 

 stones, and in which the red and purple slate and sandstones are so predominant, con- 

 tains at intervals cupriferous veins with bitumen and other minerals, particularly where 

 there are contiguous intrusions of trap rock. Thus at Norbury, between the trap rocks 

 of Wentnor on the one side and those of Linley on the other, copper veins are so 

 abundant that they were formerly much worked. In that district, these veins are of 

 high geological interest, for proceeding upwards from the slaty purple rock of these hills 

 they also penetrate the Caradoc sandstone, though the latter rests in unconformable and 

 slightly inclined positions upon the former. Thus, near Norbury, the vein containing 

 crystals of sulphate of barytes traverses the limestone beds, loaded with Pentamerus lesvis, 

 P. oblongus, and other Caradoc fossils. No copper veins of more than three or four 

 inches in width fell under my own observation. In one case these veins, though not 

 proceeding upwards, have been discovered to lie beneath the Caradoc sandstone and 

 limestone near Linley, by sinking a spring through those rocks, which gave forth water 

 strongly impregnated with copper 1 . 



1 The mineral spring of Prolimoor near Wentnor, to which my attention was first directed by my friend Dr. 

 Du Gard of Shrewsbury, probably rises from altered Cambrian rocks, though it also passes through broken 

 Silurian strata. The surface at this spot is so much encumbered with drifted materials, that no acquaintance 

 with the substrata could have been obtained, had not the Earl of Powis recently endeavoured to improve the 

 spa by clearing away this detritus. I am obliged to Mr. Marston of Aston, who directed this operation, for 

 having furnished me with specimens of the Silurian rock, which I consider to be of the same age as the lime- 

 stone of Norbury, and I have also to thank him for having detected several points of trap in the adjacent hills. 

 In fact the surrounding strata are so riddled by trap, that I have no doubt this source owes its origin to the 

 intrusion of that rock and the consequent mineral changes in the strata affected, for the limestone alluded to 



2 K 



