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stone. Bancroft also believed that silicification was a continuous process
beginning at a late stage in the intrusion of the amphibolite and con-
tinuing after the amphibolite had been locally sheared.

Dykes in great variety intrude the argillites and to a lesser extent
the amphibolite. The dykes were intruded after the amphibolite was
foliated and also after the ore-bodies were formed. ‘There are several
faults in the vicinity of the mine. Faulting preceded dyke intrusion but
was later than the shearing of the rocks. Slight movements along some
faults took place after dyke intrusion.

Some of the Hidden Creek ore-bodies outcropped and these appeared
as large, rusty exposures and large areas of silicified rock. According to
early reports the ores were locally completely oxidized to a depth of 5
feet. There was some secondary “sooty ” chalcocite at the bottom of the
oxide zone. Underground development work discovered ore-bodies that did
not outcrop. Eight ore-bodies are known, six of which have been mined.
Parts of ore-bodies Nos. 1 and 2 were visible at the surface; Nos. 3, 6, and
7 were drift covered; and Nos. 4, 5, and 8 did not reach the rock surface.

Ore-bodies Nos. 1, 4, and 5 form a fairly continuous body some 2,000
feet long on the eastern and southeastern contact of the southern half of
the S-like structure. Ore-body No. 7 is a short distance north. Ore-
bodies Nos. 2 and 3 lie in a shear zone within the amphibolite 100 to 300
feet west of the contact. Ore-body No. 6 is at the south end of the 8-like
structure, about 1,000 feet southwest of No. 1 body. Body No. 8 is not of
commercial ore and lies between Nos. 1 and 6. The ore-bodies vary
considerably in size. No. 1 is the largest and on some levels is as much
as 1,500 feet long and 250 feet wide. It has a dip length of 1,200 feet.
No. 6 ore-body is only a few hundred feet long and up to 70 feet wide.

Ore consists of solid sulphide, of amphibolite ribboned with sulphide,
of highly silicified rock with sulphides, and of all gradations between solid
sulphide and amphibolite ribboned with sulphide and between solid sulphide
and siliceous ore. The sulphides are chalcopyrite, pyrrhotite, pyrite,
magnetite, arsenopyrite, and sphalerite. The gangue consists of amphi-
bolite, or silicified argillite, or amphibolite and small amounts of actinolite,
quartz, calcite, epidote, and biotite. Locally the ore exhibits structures
present in the rocks and there are local remnants of argillite and green-
stone. These features show that the ore was formed by replacement.
Locally chalcopyrite may be so abundant that the copper content of the
ore rises as high as 10 per cent. Locally pyrrrhotite is very plentiful, and
some large sulphide bodies consist almost entirely of pyrite. On the
whole, however, the ore-bodies are of fairly uniform grade. The average
ore contains 1-5 per cent copper, about 4 ounce of silver a ton, and about
10 cents in gold a ton.

Actinolite very rarely occurs in the altered argillites. A few sulphide
veins of microscopic size were noted to be composed of actinolite and of
pyrrhotite in which the pyrrhctite was moulded around and between
actinolite crystals. Pyrrhotite, chalcopyrite, and pyrite occur in the wall-
rocks. A yellow zeolite was seen only in specimens from near the surface.
In sections of mineralized amphibolite the sulphides appear to be later than
the rock-forming minerals. In sections of siliceous argillite the sulphides
are seen to be later than the silicification.