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deposited earlier than the chalcopyrite, but this was not conclusive. This
mineral does not show any cracks nor does it contain veinlets of other
minerals, and, since such structures are the surest indicators of paragenesis,
it is often difficult to tell the relative age of the pyrrhotite. It is considered
by most economic geologists to be almost exclusively a high temperature
mineral, and though the evidence is not conclusive that the chalcopyrite
is later than the pyrrhotite still there is nothing to suggest that the
pyrrhotite is the later; therefore, it may safely be considered that the
natural sequence of deposition of pyrrhotite-chaleopyrite was followed.

The pyrrhotite is seen replacing magnetite grains and the magnetite
is apparently the only mineral which preceded the precipitation of the
pyrrhotite.

Arsenopyrite is not plentiful in the Rocher De Boule veins, but is of
two different periods. In No. 4 vein it is undoubtedly earlier than the
chalcopyrite, and numerous examples of etched and veined crystals were
seen. In No. 2 vein a reversed order is found in which beautiful, small
veinlets of arsenopyrite traverse the chalcopyrite or follow. its gangue
contact in a most regular and persistent way. This is well illustrated in
Plate VB. This specimen, from which the photograph was taken, is from
a point in the vein where the silver-lead ore comes in contact with the
chaleopyrite-hornblende ore, and it is believed that the arsenopyrite
shown in it belongs to the same late period of mineralization that produced
the silver-lead ore, whereas the chalcopyrite belongs to the earlier period
in which the chaleopyrite-hornblende ore was deposited. The arsenopyrite
was found veining hornblende and is, therefore, of later deposition. No
safflorite, gold, or léllingite, were observed in any of this arsenopyrite,
though they are plentifully associated with the arsenopyrite of the veins
on the Hazelton View claims, a short distance to the west.

Pyrite is only sparingly present and its structures indicate that it
was deposited shortly after the magnetite, and probably about the same
time as the pyrrhotite. It occurs as small disseminated crystals and is
frequently veined by chalcopyrite.

Molybdenite is the least plentiful of all the minerals present and is
seen only as small flakes sparsely disseminated through the hornblende.
Its relative time of deposition is doubtful, but it was seen replacing
arsenopyrite and chalcopyrite, and was probably deposited soon after
those minerals (See Plate VIA).

Tetrahedrite occurs in this ore, but in much smaller quantities than in
the silver-lead ore. It seems to have been deposited with the chalcopyrite
or slightly preceding it.

Much later than all the minerals so far described, and following a
period of considerable crushing, small veinlets of calcite and siderite were
formed.

Silver-lead Ore. This ore consists of large masses of banded milky
quartz containing a small proportion of zinc blende, galena, tetrahedrite,
pyrite, arsenopyrite, and chalcopyrite.

Pyrite and arsenopyrite are present only in minute amounts and are
extensively replaced by tetrahedrite and zine blende. Tetrahedrite is the
most abundant ore mineral in this type of ore; it is frequently seen sprinkled
throughout the ore, sometimes quite plentifully, with small etched crystals
of arsenopyrite, and associated with each there is usually a small area of
chalcopyrite. This structure is so common in the tetrahedrite that it might

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