298. ON THE DETRITAL TIN-ORE OF CORNWALL. 
The eastern district is bounded by the Fowey and the Camel 
and certain of their tributaries on one side, and by Devonshire on 
the other. It comprehends the great granitic range—the most 
elevated part of Cornwall*—which extends from the vicinity 
of Cardinham-bury on the south-west beyond Brea in Alternun 
on the north-east, and from Greylake near Camelford on the 
north-west to Stanton in Saint Cleer on the south-east,{ beside 
smaller bodies of similar character at Kit-Hill,* and at Gunnis 
Lake on the Tamar ;}—slate—possibly of more than one periodt 
—usually mantles round the granite, of which, however, veins and 
beds§$ either intersect or—less frequently—interlie the planes of 
cleavage ; but in one instance at least a considerable tract of slate 
—probably of no great* thickness||—is entirely surrounded by — 
granite ;—felspathic and quartzose porphyries (elvans) form broad 
C2 Gna JERI TEENSS Go G6000006Gq00000 -- 1,067 feet above the sea ;— 
Cavadomn Veisys sierccrecsteteyeub el cvevelarers so LL ANS 5, ni j— 
Iealhim~He Go o500 Blstasa lo over svotstivs eisiicier creat neul Gel tian 50 — 
IsouIeda MUR Gooaooo0cDDDKnG cov0n ab yO by » —= 
LorROnAM \WAIbY S550 60000000 Rasen OOS acs - a 
MactavcH3an, (DE ta Becue’s) Survey, pp. 14, 17, 18. 
+ Boase, Cornwall Geol: Trans: iv, pp. 173, 210, 221. De la Beche, 
Report, pp. 159, 161. Sedgwick and Murchison, Geol: Trans: v, p. 685. 
Whitley, Report of the Royal Institution of Cornwall, xxxii, (1850), p. 31. 
Holl, Quarterly Journal of the Geological Society, xxiv, p. 440. Henwood, 
Cornwall Geol: Trans: v, p. 181; viii, pp. 655-660. 
+ Berger, Geol: Trans: i, p. 123. Mohs, Thomson’s Annals of Phi- 
losophy, xiii, p. 311. Conybeare, (J. J.), Geol: Trans: iv, p. 424; Annals 
of Philosophy, (N.S.), iv, p. 401; v, p. 185; vi, p. 37. Boase, Cornwall 
Geol: Trans: iv, pp. 382-398. De la Beche, Report, pp. 56-58, 61-63, 79-81. 
Phillips, (Prof.), Paleozoic Fossils of Cornwall, Devon and West Somerset, 
pp. 164-182, 195-200. Sedgwick and Murchison, Geol: Trans: v, pp. 665, 
668. Sedgwick, Quarterly Journal of the Geological Society, viii, p. 16. 
Henwood, Cornwall Geol: Trans: v, pp. 134-136; viii, pp. 667-673, 700-703. 
Holl, Quarterly Journal of the Geol: Society, xxiv, pp. 402-406, 414-426. 
Peach, Cornwall Geol: Trans: vi, pp. 12, 51, 181, 236, 296; vil, pp. 17, 57, 
121, 125,175. Williams, Ibid, vi, p. 122, 334; vii, p.64. Couch, (J.), Ibid, 
vi, p. 189; vii, pp. 244, 249. Couch, (R. Q.), Lbid, vi, pp. 147, 219, 276; vii, 
pp. 18, 193, 273, 300, 317. Pattison, /bid, vi, p. 267; vii, p. 1, 63, 109, 132, 
208, 246. Murchison, Jbid, vi, p. 317. Giles, /bid, vii, pp. 93, 155, 169. 
Pengelly, Jbid, vii, pp. 106, 115, 211, 388, 441. Whitley, Ibid, vii, p. 336, 
Pl. iv. 
gs Webb and Geach, History of Mining in the Caradon District, p. 67. 
Henwood, Cornwall Geol: Trans: viii, pp. 656-660. 
| Ordnance Geological Map, Sheet xxv. Whitley, Geological Map of 
the Caradon Mining District. Henwood, Cornwall Geol: Trans: villi, p. 657. 
