Lodes and Gold. 593 



fissures in the rocks, sometimes running for miles, and 

 more or less filled with quartz, calc-spar, and ores of 

 metals, which yield our chief supplies of copper, tin, 

 zinc, and lead. 



It is worthy of remark that these lodes are almost 

 wholly confined to our oldest or Palaeozoic rocks. The 

 Devonian rocks are intersected by them in Devon and 

 Cornwall, and the Lower Silurian formations in Wales, 

 Cumberland, the Isle of Man, and the hills of the south 

 of Scotland, and here and there throughout the High- 

 lands. In the Carboniferous Limestone they are also 

 largely worked in North Wales, Yorkshire, and Derby- 

 shire. 



The chief districts in England where copper and tin 

 are found are in Devon and Cornwall ; and in the Lower 

 Silurian rocks of Wales, especially in Cardiganshire and 

 Montgomeryshire, there are ores of copper, and many 

 lodes highly productive in ores of lead, some of which 

 are rich in silver. No tin mines occur in that district. 

 Gold also has been long known in Merionethshire, 

 between Dolgelli, Barmouth, and Ffestiniog, sometimes, 

 as at Clogau, in profitable quantity, but generally only 

 in sufficient amount to show reason for starting com- 

 panies which occasionally lure unwary speculators to 

 their loss. This Welsh gold is found in lodes generally 

 in and near the base of the Lingula flags, which in that 

 area are talcose, and pierced by eruptive bosses of 

 igneous rocks and greenstone dykes. 



In older times extensive gold mines were worked 

 in Caermarthenshire at the Gogofau (ogofau, caves), 

 near Pumpsant, between Llandovery and Lampeter. 

 These excavations were first made open to the day in 

 numerous irregular extensive quarryings and caverns, 

 where the gold-bearing quartz-veins and strings were 



QQ 



