ORIGIN AND DEVELOPMENT OF ORE-DEPOSITS. 299 



None of these have proved very rich in the localities named, but 

 the Trewollock vein followed southwards leads to the N.S. veins, 

 which formerly yielded so largely at East Wheal Rose, — the 

 Trewinnick vein corresponds in direction with the veins of 

 Sheppards and Gwarnic (Q-arras), and followed still further, 

 Trefusis. The Trethellan vein is nearly in line with the great 

 fault, which traversing the Chiverton district, passes by 

 Treworder, through Liskes, and on by New Bridge, Killiow, 

 Devoran, and Carclew, and finally reaches the sea at Swanpool. 



The lead vein at Wheal Golden, which bears about 30° W. 

 of N. is perhaps of somewhat newer date than those just mentioned 

 — it may correspond in age with the principal cross-courses of the 

 St. Agnes, Eedruth, Camborne, and Illogan Mining districts. 

 It is probable enough that some of these latter, like the "NVest 

 Golden vein, would yield lead but for their proximity to the 

 granite, which in Cornwall and Devon has always proved 

 "uncongenial" for this metal. There is indeed a little lead in 

 the cross-courses at North Busy, Wheal Jane, Wheal Falmouth, 

 and a few other places. 



The next group of lead-bearing cross-veins is that which 

 has been worked on the south coast at Wheal Rose, and Wheal 

 Penrose, near Helston. These veins run a few degrees W. of 

 N., the greatest deviation being at Wheal Penrose, where the 

 chief lode runs about 14° W. of N. underlying E. about 75". 



The lode at Wheal Rose which has yielded considerable 

 quantities of lead and some copper ore, followed northwards 

 becomes known at Woolf 's cross-course, where it crosses the Metal 

 and Vor lodes and yields quartz only.* The same vein (so it is 

 believed) still farther to the north in Godolphin mine has yielded 

 much rich grey copper ore. 



I do not think any of the veins farther west have as yet 

 been satisfactorily indentified as belonging to this series, though 

 possibly some of the Marazion veins may be hereafter found 

 referable to it. 



*It is said with traces of gold, and it is worthy of note, that the pyrites of 

 the western end of the Wheal Metal lode contains traces of gold also. I mention 

 ^his as a matter of mineralogical interest, but I do not think the gold " payable '' 

 pr likely jbo become so hereafter. 



