48

After the formation of the faults and shear zones, the argillites were
intruded by lamprophyre and other fine-grained dykes. The dykes strike
north. In a few places their relations to the shear zones and the faults
are known, as in the Dunwell mine where a dyke follows a shear zone,
striking northwest, to a fault striking north, and continues north along
the fault. After the period of dyke intrusion differential movements still
continued, as is shown in the Dunwell mine, where the dyke already
referred to is shattered and crushed at the junction of the shear zone and
fault and here and there along the shear zone.

Later still the Portland Canal fissure zone was invaded by siliceous
and ore-forming solutions. Quartz veins formed in the many shear zones
and locally along the two faults. Some of the veins in the shear zones
and most of the vein matter in the faults consist of barren quartz. Most
of the known ore-bearing shear zones contain a dyke as well as an ore-
bearing vein. For example, in the Portland Canal, Dunwell, and Victoria
mines and on the Sunbeam claim the ore-bodies are along one or both
sides of dykes, and in the Dunwell mine ore lies along the dyke both where
it follows the shear zone and where it continues along the fault. It seems
that in some way the dykes guided the ore solutions and perhaps helped to
keep them within definite channels.

The veins on one side of either of the two main faults are believed
to be distinct from those on the other side. The veins thus form three
groups. One group consists of the veins west of the west fault; the second
group consists of the veins lying between the faults; and the third group
consists of the veins east of the east fault.

In the Dunwell mine the western fault (Fault A, Figure 1) is inter-
sected by adits Nos. 2, 3, and 4, and is known as the North-South vein.
On Figure 1 this vein as found on adit No. 2 level is labelled A-2, where
found on adit level No. 3 it is labelled A-3, and in the case of No. 4 level.
A-4. Farther south the fault is also cut by the adit known as the Portland
Canal tunnel and on Figure 1 is labelled A. The eastern fault is crossed
near the face of the Portland Canal tunnel and on Figure 1 is labelled B.

The most westerly vein of the group of veins west of the western fault
is exposed in the Portland Canal tunnel and on the figure is vein No. 1. Pro-
ceeding northward the remaining known veins of the western eroup are
" numbered consecutively from 2 to 10. Veins Nos. 5 and 7 are exposed at
the surface and also underground on the George E claim. Vein No. 5
divides underground into veins Nos. 5 and 6. The three veins crossed by
No. 4 adit, Dunwell mine, are probably continuations of veins Nos. 5, 6,
and 7. The vein crossed by No. 3 adit, Dunwell mine, is probably No. 7
vein. A vein exposed at the surface a short distance north of No. 1 adit.
Dunwell mine, is probably east of No. 7 vein and, therefore, is called No. &
vein. If it continues north into the Sunbeam claim it should lie very near
the more westerly of the two veins on the Sunbeam claims and conse-
quently, this vein, known as the Sunbeam vein, is considered to be No. 8
and the more easterly, the Sulphide vein, becomes No. 9. No. 8 vein
projected north along its strike would practically lie in the position occu-
pied by the most westerly (Main Reef vein) of the veins of Victoria
mines, and this vein is, therefore, considered to be No. 8. The next vein