XV 
large scale, and as a general fact be regarded to coincide in direc- 
’ tion; but they dip at diverse angles, and sometimes different 
ways, and thus often intersect. Such intersections are neither 
peculiar to one rock, nor to veins affording merely one kind of 
ore ; for some occur in granite, other in slate, several yield tin- 
ore only, many afford copper-ore alone, and a few contain both. © 
The results of these interferences are as various as the conditions 
under which they occur; sometimes they unite and continue to- 
gether for considerable distances, but at length separate; not 
uncommonly one is displaced (heaved) horizontally or (thrown) 
vertically by another; and now and then both seem disordered, 
and to have lost their distinctive characters near the point of their 
intersection. As a general fact the lodes which contain a mixture 
of tin and copper ores are wider than those which afford either 
ore alone. Moreover /odes maintain a greater average width in 
slate than in granite, and within one hundred fathoms of the 
surface than at greater depths.* On passing from one rock to 
another, and from riches to poverty, the widths of /odes frequently 
change ;f under ordinary circumstances, however, each individual 
lode commonly maintains a characteristic breadth.t The direc- 
tions of the Jodes,§ in different mining districts, are neither per- 
fectly identical, nor—owing to slightly unconformable flexures in 
confronting parts of neighbouring Jodes—are those of even the 
same district strictly parallel. Indeed, central parts of the county, 
are traversed by—so to speak, two systems—the Champion-lodes 
and the Cauwnter-lodes, each of which maintains its own normal 
* Todes which yield the ores of tin and copper average 4:7 feet in width; 
a 6 EINE OLE hater) or otct oy shaver sk che By BO) on ay 
Ig i copper-ore .......... za 220 ieee . 
3 in granite.........- COO ODUD SOC UmO OS 3 Sole 3 
ar LY SAL ese AGA Wie oy Manat era 35 Sah iy 
5% at less than 100 fathoms deep...... oy 3-9. 53 
BUM ONS Le We col uninmT A Milast t ksteh ete tare 3° ep 
+ Borlase, Natural History, p. 152. Pryce, Mineral: Cornub: p. 79. 
Phillips, (W.), Geol: Trans: ii., p. 116. Thomas, (R.), Report, p. 19. 
Carne, Cornwall Geol: Trans: ii., pp. 88, 95, 105. Boase, Ibid, iv., p. 444; 
Primary Geology, p. 171. Taylor, Reports Brit: Ass: (1833), p. 4. Burr, 
Mining Review, ii., p. 217. Fox, Reports of the Royal Corn: Pol: Society, 
iv., p. 84. Phillips, (Prof.), Geology, (Lardner’s Cyclopxdia), p. 129. De la 
Beche, Report, p. 343. Henwood, Cornwall Geol: Trans: v., pp. 241-2438; 
Vili., p. 677. 
t Ibid, v., p. 241. : 
§ Borlase, Natural History, p. 145. Pryce, Mineral: Cornub: p. 80. 
Phillips, (W.), Geol: Trans: ii., p. 113. Thomas, (R.), Report, p. 19. Carne, 
Cornwall Geol: Trans: ii., p. 85. Fox, Reports of the Royal Cornwall Poly- 
technic Society, iv., p. 83. Dela Beche, Report, pp. 302-309. Buckland, 
