192 ON THE DETRITAL TIN-ORE OF CORNWALL. 
operations are still in progress, and to these, most of the following 
notices relate. ‘ 
Between the Land’s-End and Saint Ives the granite and the 
slate, in contact with it on the north and north-east, are traversed 
by metalliferous-veins (Jodes) ; but their numbers, directions,* and 
mineral characters differ in various parts of the district. Towards 
the south they are poorer and less numerous than in any other 
portion of the neighbourhood ; yet one of the few mines} wrought 
here has yielded some amount of wood-tin-ore. The central region 
is more productive; and, in one spot, at least, tin-ore not only 
forms numberless thin veins, but is so generally disseminated, 
that—so to speak—it is an ingredient of the rock.t Near the ~ 
northern and north-eastern boundaries of the several series, how- 
ever, many rich odes have been, and—indeed—still are, largely 
and profitably worked. In some instances also of-shoots (if they 
may be so designated) of great, but of yet unascertained, length, 
Voyages Meétallurgiques, iii, p. 188. Klaproth, Jfineralogical Observations, 
p. 12. Maton, Observations on the Western Counties, i, p. 152. Rashleigh, 
British Minerals, i, p. 5; ii, p. 24, Pl. xxi. Cornwall Geol: Trans: ii, p. 281. 
Berger, Geol: Trans: i, pp. 153, 161. De Lue, Geological Travels, iii, pp. 
155, 211. Smith, Geol: Trans: iv, p. 409. Hawkins, (Sir C.), Cornwall 
Geol: Trans: i, p. 235. Majendie, /bid, p. 237. Sedgwick, Annals of Phi- 
losophy, ix, p. 249. Hawkins, (John), Cornwall Geol: Trans: ii, p. 235. 
Paris, Guide to the Mount’s-Bay, p. 197. Michell, Manual of Mineralogy, p. 
72. Carne, Cornwall Geol: Trans: ii, pp. 293, 331; iv, (1830), pp. 47, 95, 
vi, p. 233. Boase, /bid, ili, p. 31. Thomas, (R.), History of Falmouth, p.31. 
Henwood, Cornwail Geol: Trans: iv, (1828-9), p. 60; v, pp. 14, 34, 42, 55, 
68, 90,* 110, 129, 141; viii, p. 695 ; Address to the Royal Institution of Corn- 
wall Journal, No. xi, p. x. Dela Beche, Report on the Geology of Cornwall, 
Devon, and West Somerset, p. 401. Barratt, /bid, p. 403. Allen, History of 
Liskeard, pp. 4, 27, 204. Rogers, (J. Jope), Cornwall Geol: Trans: vii, Dp. 
352. Polwhele, Historical Views of Devonshire, i, p. 110. History of Devon- 
shire, i, p. 158. Lysons, Devonshire, i, p. celxx. Rowe, Perambulation of 
Dartmoor, p. 68, 255, 312. Von Cotta, Ore-Deposits, p. 421. 
* Carne, Cornwall Geol: Trans: ii, p. 321. Henwood, Ibid, v, pp. 9. 250; 
Table, ciii; viii, p. 674; Journal of the Royal Institution of Cornwall, No. 
xiii, (1871), p. xvi. Moissenet, Annales des Mines, 6me Série, iii, p. 161. 
+ Klaproth, Mineralogical Observations, p. 21. Carne, Cornwall Geol: 
Trans: iv, p, 95. Henwood, Jbid, v, p. 32. 
} Henwood, Cornwall Geol: Trans: v, p. 235; viii, p. 664; Journal 
of the Royal Institution of Cornwall, No. xiii, p. xiii. 
