364 On the Bristol Copper Mine. 
line, have never been well ascertained, and must be somewhat 
irregular, as would be expected from the nature of the deposit. 
Eustis’s level, going north from the 20-fathom cross-cut, has been 
driven along a well-marked and regular wall, which has been 
commonly called the foot wall of the mine. This dips, at an 
° to the East, preserving a very near parallelism with 
the line of contact of the formations. The same kind of wall is 
seen in the 30-fathom level immediately beneath, where it is 
observed in the 20; but in neither level can it be traced for more 
than one or two hundred feet. There is nothing in the nature 
of the wall to indicate that ore might not be found beyond it, as 
appearances similar to this are observed in the ore-bearing ground 
of the mine. The excavations indicate that there was a tend- 
ency of the metalliferous matter towards this limit, and that there 
is not much probability of finding large bunches of ore beyond it. 
It is worthy of remark, however, regarding the ore-ground within . 
the limits just described, that the average distribution of the vit- 
reous copper is very uniform, so much so that for a long period it 
has been found profitable to crush and work over nearly every 
stone from this belt raised in working the mine. 
e ore-ground just described was from the time the mine was 
first opened up to a recent period, considered as the only source 
in which the’yield of copper was to be sought. Not long since, 
however, attention began to be called to a belt of soft rock, which 
lies next adjacent to the sandstone, and, of course, between it and 
the metalliferous belt just described. This belt is known as the 
“great flucan,” (see diagram on previous page, ) and it consists of 
a talco-micaceous slate completely disintegrated and softened by 
some chemical agency, with the exception of a few bands and 
nodules of hard rock, but which are of very limited extent, com- 
pared with the softer portion. The flucan contains throughout its 
whole mass vitreous and other ores of copper, usually dissemina- 
ted through it in small particles, so as hardly to be visible to the 
naked eye, but occasionally concentrated into bunches and strings 
of considerable size. The width of the great flucan is 27 feet in 
the 20-fathom Jevel, but it increases rapidly as the workings de- 
scend, being respectively 38 and over 50 feet, in the 30 and 40- 
fathom level. If this increase in width were to continue in 
depth, the flucan will meet the so-called foot-wall of the mine at 
or near the 80-fathom level, occupying in this place a width of 
about 120 feet. But that such an increase in its dimensions con- 
tinues downwards indefinitely, seems hardly probable ; it is more 
likely that it will be found to be a lenticular mass swelling out 
to great dimensions, and then gradually contracting again. ‘The 
mass of flucan has been traced on the surface and opened at vatl- 
ous points. At the distance of 700 feet to the southwest, from the 
engine-shaft, it has near the surface an inconsiderable width, 
