XX1i 
are generally sprinkled with iron-pyrites, earthy black copper-ore 
and malachite, which are succeeded by vitreous copper, and at 
length all are replaced by copper-pyrites.* But notwithstanding 
the ores of tin and of copper usually affect different Jodes, and 
indeed different rocks,+ they are intimately mixed} in some of 
the largest and most productive mines. The ores of lead § 
mostly occur at some distance from the granite; and are limited 
to groups of Jlodes traversing schistose rocks, which are some- 
times fossiliferous. || Notwithstanding the rarity of symmetrical 
arrangement in the constituents of lodes, one ingredient (the 
leader), or an admixture of ingredients, sometimes maintains a 
certain continuity for considerable lengths and depths; but at 
least as frequently the various components are irregularly mingled. 
It has been already stated that compact portions of the lodes are 
chiefly siliceous; and that sometimes they may be entirely of 
quartz; yet now and then the whole substance is metallic. The 
alteration from poverty to riches, however, is seldom a sudden 
one; for on the outskirts of rich bodies of ore, granules, small 
masses, and short thin branches impregnate the vein-stone.™ The 
* Pryce, Mineral: Cornub: pp. 88, 91. Phillips, (W.), Geol: Trans: 
ii., pp. 117, 119. Carne, Cornwall Geol: Trans: i1., p. 95. Fox, Reports of 
the Royal Corn: Pol: Society, iv., p. 97. Dela Beche, Report, pp. 326-327. 
Henwood, Cornwall Geol: Trans: v., pp. 226, 228; viii., p. 676. Smyth 
(Perey) Metallurgy, i., pp. 313-314. 
+ Pryce, Mineral: Cornub: p.75. Henwood, Edin: New Phil: Journal, 
xxil., p. 157. Cornwall Geol: Trans: v., pp. 190-194; viii., p. 680. De la 
Beche, Report, p. 327. Von Cotta, Ore-Deposits, p. 418. 
+ Pryce, Mineral: Cornub: p. 92. Klaproth, Fossils of Cornwall, pp. 
21, 42-58. Berger, Geol: Trans: i., p. 167. Phillips, (W.), Ibid, ii., p. 154. 
Thomas, (R.), Report, p. 20. Fox, Reports of the Royal Corn: Pol: Society, 
iv., p. 95. Henwood, Cornwall Geol: Trans: v., p. 207; viii., p. 677-678. 
§ Borlase, Natural History, p. 210. Pryce, Mineral: Cornub: p. 58. 
Klaproth, Fossils of Cornwall, p. 30. Polwhele, Cornwall, iv., p. 134. 
Berger, Geol: Trans: i., p. 173. Lysons, Cornwall, ccix. C. 8. Gilbert, Corn- 
wall, i., p. 259. Hitchins and Drew, Cornwall, i., p. 624. Carne, Cornwall 
Geol: Trans: i., p. 120; i1., pp. 112,118. Michell, Manual of Mineralogy, 
pp. 9,14. Boase, Cornwall Geol: Trans: iv., p. 193. Davies Gilbert, Corn- 
wall, iii., p. 47. Fox, Reports of the Royal Corn: Pol: Society, iv., p. 101. 
De la Beche, Report, pp. 284, 287, 610-612. Hunt, Mineral Statistics, 
Passim. Allen, History of Liskeard, pp. 421, 422, 425, 426, 431, 432. 
Henwood, Cornwall Geol: Trans: v., pp 54, 108, 140, 193, 255, 268; viii., 
pp. 707-711, 720; Reports of the Royal Institution of Cornwall, XXXI1l., pp. 
39-43. Giles, Cornwal! Geol: Trans: vii., pp. 200-207. Salmon, Mining and 
Smelting Magazine, li., pp. 78-84, 211- 218. Webb and Canale. Caradon and 
Liskeard District, pp. 16-24, 26-27, 36-38. 
|| Nearly, if not quite, forty years ago, an neni was discovered by 
the late Mr. W. Mansel Tweedy—sometime President of the Royal Institution 
of Cornwatl,—in slate adjoining the lode at Goonhavern in Perranzabuloe. 
4 Henwood, Cornwall Geol: Trans: v., pp. 208-210; viil., pp. 679, 708. 
