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94

The persistence in the trend of the outcrops of the main belt of veins
indicates that no large displacements of the ore veins by faulting have
taken place. In the second tunnel east of the creek on the Molyb claim
is a fault striking north 23 degrees east and displacing the upper part of
the quartz vein southwest for a few inches. In the shaft on the same claim
a flat fault offsets the upper part of the vein about 4 feet to the northeast.
In the gully southeast of the shaft a number of evident faults occur and
some of these have offset the veins slightly. One of them strikes north
38 degrees east and dips southeast 80 degrees.

ORIGIN OF THE MOLYBDENITE AND NEIGHBOURING GOLD-COPPER ORES.

Timothy mountain is made up of a huge mass or batholith of quartz
diorite. Through this mass are a number of fracture zones in which are
found dark green, basic dykes, light-coloured pegmatites, aad quartz veins.
The pegmatites are accompanied by tourmaline, magnetite, epidote, and
quartz veins, proving the presence of hot magmatic. vapours during their
crystallization and indicating the presence close below of molten magma.
The dark, basic dykes are probably earlier than the pegmatites. Both are
fractured and traversed by quartz veins carrying molybdenite. The
molybdenite veins are accompanied by replacement of the country rock
by sericite, biotite, epidote, quartz, and pyrite; and since all of these
minerals can form under great heat and pressure, and molybdenite is gen-
erally so formed, it is probable that the molybdenite veins were formed near
the hot intrusive body immediately after the pegmatites and perhaps
simultaneously with some of them, that is, while their parent magma
was still hot. The presence of galena and zine blende among the minerals
occurring in the gold-silver-copper ores 13 miles to the northwest indicates
that they crystallized under lesser heat and pressure than the molybdenite,
either nearer the surface or farther from the intrusive body. Their structure
and geological relations are so similar in character to those of the molyb-
denite that it seems probable they were derivedfrom the same source
and at the same time. The geological age of the ores cannot be proved,
but is probably post-Jurassic and pre-Miocene.

ORE VALUES.

With no underground workings to speak of, there is very little to
indicate whether the ore varies in value, either laterally or in depth. It
is evident from an inspection of the veins, however, that in a great many
of the outcrops weathering has impoverished the ores for the first 2 to
4 feet from the surface. In an open-cut on the Kagle claim, the most
easterly and highest of the workings, the writer sampled an ore-body
consisting of two quartz veins with altered country rock and vein matter
between (Plate XVII). The sample included everything within the vein
zone for a width of 30 inches, 4 feet from the surface. The assay by F. W.
Baridon of the Mines Branch yielded 0-86 per cent molybdenum (that
is, 1-43 per cent molybdenite) and no copper. No further assays are
available, but from the quantities of ore prepared for shipment and from
rough estimates of the cubical content of vein matter involved, it is con-
cluded that in a number of places at least, the assay results approximate
the values below the zone of weathering, that is, from a depth of 4 feet
downward.