Vol. 54.] LIMESTONE OF THE COUNTRY AEOTTND LLANDUDNO. 383 



Great Orme's Head is of an undulating character, and the limestone 

 being continuously exposed in terraced cliffs, weathered surfaces, and 

 quarries, the strata may be examined over the entire extent of the 

 headland. 



Mr. Robert Hunt, in his ' British Mining,' 1884, states that 

 ' the Romans found copper in the Great Orme's Head, and worked 

 it extensively. In Llandudno, when digging for the foundations of 

 buildings, the modern excavators have come upon the soil of the 

 Boman level, coloured by the washings of the ore.' He also states 

 that implements of waterworn stone, horn, and bronze have been 

 discovered on both the Great Orme's Head and at Llandudno. 

 Copper seems to have been tbe principal, if not the only ore obtained, 

 but the work was discontinued about 30 years ago. The mines 

 were still worked in 1859, for in that year I obtained specimens of 

 crystallized cbalcopyrite or pearlspar from the miners. According 

 to the map of the Geological Survey, there are four north-and-south 

 lodes running parallel for about | mile, and all within 200 yards 

 from east to west. Sir A. Ramsay states that black shales were 

 reached in the old mine- shafts, and possibly belonged to the 

 Llandeilo or Bala Beds beneath the limestone.^ This may have 

 been at the depth of 400 or 500 feet, but the position of the shafts 

 referred to is now unknown. 



There is no plan of the outcrop of the lodes, and no information 

 as to the workings is available at Llandudno. The only such 

 ground-plan is one preserved at the Home Office, and it shows the 

 four lodes running exactly north and south, with two cross-veins 

 striking N.N". W. intersecting and heaving the older veins out of their 

 course. Another cross-vein, running north-east, does not disturb 

 the others, and they are all shown in the accompanying reduced copy 

 (fig. 1, p. 384) from a tracing of the original plan, which also com- 

 prises two other plans, showing the heaving of the veins and the 

 distribution of the ore. I am indebted to Prof. C. Le Neve Foster, 

 H.M. Inspector of Mines, who resides at Llandudno, for facilities in 

 obtaining access to the plan here described. 



Mr. Hunt's description of the veins is the only published account, 

 and from his work it appears that they were alone productive in 

 the crystalline rock, and always associated with it, but the term 

 * dolomite ' is not used. The crystalline and the non-crystalline 

 beds, he states, alternate with much regularity, and the productive 

 character of the veins changes with that of the rock. When the 

 four principal veins are crossed by others, and the intersection occurs 

 in the crystalline rock, the deposit of copper pyrites is greatest. The 

 ore occurs all through the crystalline rock, but the veins can scarcely 

 be traced far into the ordinary limestone, and this explains the 

 occurrence of so many trial-holes which do not seem to have led to 

 any profitable result. These holes were evidently sunk along the 

 supposed northern prolongation of the four principal lodes; but 

 although the limestone is often exposed, no veins or fissures are 



1 Mem. Geol. Surv. vol. iii, ' Geol. of North Wales,' 2nd ed. (1881) p. 308. 

 Q. J.G. S. No. 215. 2e 



