ORIGIN AND DEVELOPMENT OF OBE-DEPOSITS. 135 



at Balnoon were known as the Garth, and the North Vervis 

 Veins ; but " besides occasional enlargements of the lodes from a 

 few inches to 30 or 40 feet in breadth, there are still larger 

 masses of tin ore wholly unconnected with any vein, and 

 surrounded on all sides by an extremely hard and very coarse- 

 grained granite. These are discovered almost by accident, for 

 I have known more than one of them found by extending the 

 excavation where there existed no other indication than a mere 

 joint in the rocks, which contained no mineral, and was perceptible 

 only from the slow oozing of a minute quantity of water between 

 its faces."* 



East Wheal LoveU. This mine is in the parish of Wendron, 

 and the remarkable tin deposits discovered in 1875 were thus 

 described by Dr. Foster. ' ' The lodes are usually very narrow, 

 sometimes a mere joint or line of division in the rocks — but 

 occasionally a couple of inches thick ; they consist of quartz, a 

 little clay, and red oxide of iron, and per se are utterly valueless. 

 In some places however you get curious deposits of tin on both 

 sides of the vein (fig. 3, Plate iii), occupying very little space but 

 extremely rich, consisting of kaolinized granite containing much 

 gilbertite and schorl, "f The importance of these deposits is 

 indicated by the fact that from very small workings, tin to the 

 value of £39,000 was sold in a period of 20 months from 

 October, 1869, to May, 1871, yielding a profit of £27,000. At 

 one time the end of a drift in one of these bodies was valued at 

 £1,000 per fathom. 



The Lovell, Wendron. A very similar deposit, also in 

 altered granite, occurs here — the lode itself being somewhat more 

 defined (fig. 4, Plate iii) and very productive in certain shoots or 

 "pipes." The tin in the "lode" 0.0. was accompanied by 

 blende and chalcopyrite, as well as by schorl, gilbertite, 

 kaolin and quartz.j The " cab." B.B, was composed of quartz, 

 mica, gilbertite, chlorite, pyrites, chalcopyrite, and schorl; and 

 like the "lode" was traversed by joints containing nothing but 

 a little schorl, gilbertite, and kaolin. In fact if it had contained 



* Henwood, Trans. Roy. Geol. Soc. Corn., V, p. 20. 



fTrans. Eoy. Geol. Soc. Corn., ix, p. 167. The paper is well illustrated. 



J Foster, Quart. Journ. Geol. Soc, 1878, p. 649. 



