376 V. DOLMAGE.

contained a perfectly developed lattice structure, in which the
covellite formed the background. These alterations indicate that
considerable surface oxidation has taken place in this ore and it
is believed that these processes have produced that part of the
hematite which is clearly a late component of the ore.

The evidence favoring secondary hematite is unusually clear
in these ores. The hematite veinlets are fine and persistent, fol-
lowing cracks in the magnetite as well as the margins of the
grains, and do not exist apart from the magnetite. The existence
of secondary hematite is gravely doubted by many eminent geol-
ogists and the question is a prominent one in current discussion
on secondary enrichment. _

The hematite-chalcopyrite ore found at the southwest end of
the vein consists of a large amount of chalcopyrite and specu-
larite with small amounts of bornite, tetrahedrite and magnetite.
The striking feature of this ore is the large amount of specu-
larite which forms veins 2 or 3 inches in width. The chalcopyrite
occurs in massive veins and contains many small irregular areas
of bornite with a little tetrahedrite. The chalcopyrite replaces
the hematite blades rather extensively, cutting into their sides
and often dividing them into irregular fragments. The bornite
is in an advanced stage of alteration to covellite and chalcopyrite,
the latter mineral forming an exceedingly fine lattice structure in
many of the bornite grains. The chalcopyrite is completely fresh.
The tetrahedrite is not noticeably plentiful, and is inclined to be
located near the bornite. It seems to be of an earlier period than
much of the chalcopyrite. Limonite is plentiful in this ore and
can be easily seen replacing the hematite and chalcopyrite, and in
places, the magnetite. The chalcopyrite is only slightly attacked
and for the most part is conspicuously fresh. This part of the
vein is also surprisingly rich. Specimens of the pure chalco-
pyrite collected by Galloway,’ of the British Columbia Bureau
of Mines, assayed: gold, 0.08 oz.; silver, 87.5 0z.; copper, 32.8
per cent. A sample of magnetite associated with bornite from
the same opening assayed: gold, 0.20 oz.; silver, 25 oz.: copper,

1 Galloway, J. D., “ Mineral Resources of a Porton of the Omineca Mining
Division,” British Columbia Bureau of Mines, Bull, 4, 1915, p. 53.