296 OBIGIN AND DEVELOPMENT OF ORE-DEPOSITS. 



principal cementiBig material. One member of the group 

 appears to extend northward as far as Venterden, near 

 Stockeclimsland. 



Passing over another band of 3 or 4 miles, we arrive at 

 another important group of nine or ten lead-bearing cross-veins, 

 all of which occur within a space of 2 miles. The most notable 

 first appears near Egloskerry, passes through North Yeoland to 

 Wheal Trelawney and Wheal Mary Ann — a distance of 10 or 12 

 miles.* Its course is very nearly 5° to 10° W. of N., it dips E. 

 about 85**, and it has yielded immense quantities of rich galena 

 at the two mines named. This is one of the very few veins in 

 Cornwall which has yielded Barytes as a veinstone. Near 

 Holloway's Cross it carries the boundary line of the Upper 

 Devonians suddenly one-third of a mile to northward. It is 

 crossed at an acute angle at North Yeoland by a vein running 

 about 25 W. of N. The vein which has been worked further 

 S.W. at Herodsfoot for lead belongs to this group also.f It 

 runs from 8 to 12® W. of N. and dips steeply to the E. It is 

 nearly parallel to the Valley of the Duloe. 



Wheal Ludcott is about 1^ miles N.N.E. of Trelawney. 

 Here are two parallel lodes running nearly N.S., and dipping 

 E. TC to 80°. These lodes are very close together, and about 

 half-a-mile E. of the Trelawney lode. 



A little to the north and west of the Trelawney mine is the 

 very rich Caradon district, where a group of 3 or 4 cross-courses 

 is associated with some of the richest copper veins ever 

 discovered in the West of England — all of which, however, are 

 now abandoned. 



The great cross-course at Phoenix mine bears very nearly 

 true north like the Trelawney lead lode. It intersects and 

 heaves the Phoenix lode to the left and the Wheal Prosper lode 



*This is the lode traversed and heaved by the "slidy ground" already 

 referred to. 



+ Herodsfoot is situated at the boundary of the parishes of St. Pinnock and 

 Lanreath, about 7 miles S.W. of Caradon. It is "the oldest mining work in the 

 neighbourhood of Liskeard, is rather curiously situated at the confluence of four 

 steep valleys, through the principal of which the Duloe flows nearly due south to 

 its junction with the Looe."— Salmon, M. ^ 8. Mag., 11-211. From 1844 to 1868 

 the following profits were made : — Wheal Trelawney ^856,914, Wheal Mary 

 Ann .£65,685, Herodsfoot ^49,348.— Henwood, VIII, 719. 



