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edges of areas of sphalerite included in the galena. Dots and rods of chal-
copyrite are included in the sphalerite, but are rare in the galena. The
conclusion is suggested that tetrahedrite is a result of the replacement of
sphalerite and included chalcopyrite by the surrounding ore fluid, the cop-
per for the tetrahedrite being supplied by the chalcopyrite inclusions.

Several properties in the vicinity of the Emperor and Lakeview mining
properties contain much drusy vein quartz. This drusy quartz may have
been formed by surface action. In some of these properties jamesonite and
other lead sulphantimonides are present. In the L and L Glacier Creek
mines an unidentified lead sulphantimonide occurs in narrow veinlets cut-
ting across the other vein matter. It is clearly later than the other ore
minerals and may be of secondary or surface origin.

AGE OF THE DEPOSITS

It is believed that the Coast Range batholith was intruded in late
Jurassic or early Cretaceous time. It is also believed that the ore deposits
of the area were derived from the batholith at the time of intrusion. If
these assumptions are correct the deposits are early Cretaceous or slightly
older. The ore deposits are assumed to be of one age, but the intrusion
of the batholith may have taken considerable time or may have taken
place in several stages, and ore deposits may have been forming through-
out the whole of the intrusive period or at each of the possible stages of
intrusion. No evidence is available that supports one of these conceptions
more than any of the others.

FUTURE OF THE AREA

The future of the area can be considered under two headings: (1)
future of deposits under development; and (2) future from the point of
view of undiscovered deposits.

The future of the known deposits pertains to the extraction of the
present ore-bodies and to the proving of greater tonnages. From the known
properties it would seem that the Marmot River part of the area, though
considerably smaller than the Bear River part, will produce the bulk of
the high-grade ore. The lower grade deposits, however, seem more
promising in the Bear River part. As for undiscovered mineral deposits
little can be said except that both parts of the area warrant thorough
prospecting.

It is impossible to tell what places are most favourable for prospect-
ing, as the origin of the ores is not fully understood. The known deposits,
however, provide some information that may assist in the discovery of
other deposits.

The four areas containing chiefly copper deposits contain as well
undiscovered copper deposits. Bear River ridge between the Prince John
and Dalhousie groups of claims probably contains undiscovered copper
deposits.

The mineral belt near the batholith on the south fork of Marmot
river is apparently interrupted north of the Silverado mine. Many min-
eral deposits occur between the Silverado mine and the Harner group at