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galena, and zinc blende, with minor amounts of chalcopyrite, native gold,
and electrum. Much of the ore is fairly solid sulphide with interstitial
quartz gangue, but locally quartz gangue is so plentiful that the body might
be called a quartz vein. From the surface to a depth of 600 feet much
of the ore in the Premier mine contained more than 100 ounces of silver
a ton in tetrahedrite, argentite, ruby silver, native silver, and other
silver minerals, and several ounces of gold a ton occurring mainly as native
gold and electrum. The Premier deposits occur in orthoclase and quartz
porphyry containing many inclusions of sheared and altered tuffaceous
rocks. Deposits much like those of the Premier mine occur elsewhere in
Salmon River district in similar rocks, but most of these other deposits
contain too little gold and silver to be valuable. The high-grade gold-
silver type of ore so far as is known occurs only in porphyry country rock.

By increase in the content of lead, zinc, and copper, and decrease in
the gold and silver values, deposits of different appearance and as a rule
much lower grade result. At the Porter Idaho and Prosperity mines of
Marmot river, for example, the deposits are veins in general less than 6
feet wide and consisting mainly of high-grade silver-lead ore. The prin-
cipal mineral is galena, but there is much silver in silver minerals and in
tetrahedrite. Examples of veins rich in zinc are those at the Dunwell mine
where gold, silver, lead, and zinc were all of value and were recovered in
mining. Deposits of this mixed type are commonly rather low in grade
and must be concentrated prior to shipment. An increase of the copper
content, as in some of the deposits at the Big Missouri mine, results in very
complex ores, none of which has yet been mined. The lead-zinc type of
mineralization occurs in deposits of many sizes and shapes. Commonly
they are veins with definite walls and lying in argillites or voleanic rocks.
Some of the veins are essentially quartz veins and only locally contain sul-
phide mineralization of the pyrite-galena-sphalerite type. In some of the
veins on the Harner group the principal values are in gold. In some places,
as on the Ben Bolt property, the mineralization is disseminated and forms
tabular bodies 100 feet or more thick very sparsely mineralized with pyr-
ite, galena, and sphalerite.

The deposits of the gold-silver or Premier type lie in porphyry and
have a distinctive siliceous, pyritic appearance. It may be that these
deposits are related in origin to the porphyry, but possibly the distinctive
features of this type are due to the fact that the country rock is porphyry
and the writer believes that this type and other types of the group although
widely distributed are related to the Coast Range batholith. It is notice-
able that gold and copper are more plentiful in the deposits of this group
that occur near the batholith than in those farther away. As the gold
and copper-bearing minerals are considered to indicate somewhat higher
temperature conditions than the other minerals in these deposits, there thus
appenm to be a zonal arrangement with respect to the edge of the batho-
ith.

In Salmon River district production has been almost entirely from
deposits of this group, the chief producer being the Premier mine which
affords gold and silver with minor amounts of lead and zinc. In Bear River
district the ore mined has been mostly from deposits of this group, and