Xill 
ferruginous matter; and not uncommonly with felspathic clay. 
’ Quartzose portions of the elvans contain microscopic cavities gene- 
rally similar to—but in some respects different from—those found 
in quartz where it is an ingredient of the granite; yet, like them, 
empty in some, but containing either liquid or gaseous matter in 
other places.* Throughout the Mining districts the elvans usually ~ 
bear a few degrees N. of E.—S. of w.;f but in other parts of Corn- 
wall they sometimes take a nearly meridianal{ direction. Their 
dips—averaging, perhaps, from 40° to 60°—are less than those of 
the Jodes which intersect them,§ but greater than the dips of the 
cleavage planes of the slates they intersect. 
The serpentine is traversed by veins which, at intervals, con- 
tain native copper ;|| but scarcely in sufficient quantity to give 
the rock a place in the metalliferous series. 
Tin-ore occurs in granules disseminated through, and in short, 
thin, veins intersecting, as well the granite™ as the elvan ;** and 
* Sorby, Quarterly Journal of the Geological Society, xiv., pp. 485-488, 
Fig. 104-111. 
+ Carne. Cornwall Geol: Trans: i., p. 99; i1., p. 79. Thomas, (R.), 
Report, p. 17. Fox, Reports of the Royal Cornwall Polytechnic Society, iv., 
(1836), p. 83, De la Beche, Report, pp. 174, 178, 180, 182. Henwood, 
Cornwall Geol: Trans: v., p. 160; vili., pp. 660-661. 
+ Pryce, Mineral: Cornub: pp. 74, 75. Dela Beche, Report, p. 179. 
§ Carne, Cornwall Geol: Trans: i., p. 99; ii., p. 80. Henwood, Ibid, 
v., p. 160, 161. 
|| Rashleigh, British Minerals, i., p. 31, Pl. xvii., Figs. 3, 8. Majendie, 
Cornwall Geol: Trans: i., p. 33. De la Beche, Report, p. 98. Greg and Lett- 
som, Manual of Mineralogy, p. 304. Garby, Cornwall Geol: Trans: vii., p. 88. 
~G Borlase, Natural History, p. 160. Pryce, Mineral: Cornub: p. 81. 
Jars, Voyages Métallurgiques, iii., p. 190. De Luc, Geological Travels, iii., 
p. 348. Berger, Geol. Trans., O.S., i., p. 120. Sedgwick, Trans: Cam- 
bridge Phil: Soc: i., pp. 104-105; Geol: Trans: iii., p. 453; Address 
to the Geological Society, Phil: Mag: and Annals, ix., p. 284. Carne, 
Cornwall Geol: Trans: ii., p. 92. Von Oeynhausen and Von Dechen, Phil: 
Mag: and Annals, v., pp. 241-242. Boase, Cornwall Geol: Trans: iv., 
pp. 239-240. Hawkins, Ibid, p. 476. Davey, Ibid, pp. 484-485. De la 
Beche, Report, pp. 190, 346, 347. Henwood, Cornwall Geol: Trans: v., pp. 15, 
20, 53, 94, 119, 122, 132, 146; viii., pp. 664-666. 
Similar deposits of tin-ore in the granite of other countries have been 
described by—Jars, Voyages Métallurgiques, iii. Hawkins, Cornwall Geol: 
Trans: ii., pp. 39,40. Manés, Annales des Mines, viii., (1823), pp. 513, 
515, 520; 1x., pp. 283-287, 463-466. Tremenheere, (G.B.), Cornwall Geol: 
Trans: Vi., pp. 73, 74. Van Diest, Banca, (Translated by Foster), pp. 53, 
62. Von Cotta, Ore-deposits (Translated by Prime), pp. 106, 123-124, 382. 
Gold-like tin-ore is disseminated through the granite of various 
countries. Herbert, Asiatic Researches, i., p. 236. Murchison, De Verneuil, 
and Von Keyserling, Geology of Russia, i., p. 483. Clarke, Quarterly Journal 
of the Geological Society, xi., p. 403. Selwyn, Ibid, xiv., p. 536. Henwood, 
Cornwall Geol: Trans: viii., p. 175. 
** Borlase, Natural History, p.91. Rashleigh, British Minerals, ii., 
