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argillite and approach, a little, to the limestone type. Replacements in
schistose rocks resemble somewhat those inbeds of tuff, but in the schists
the ore minerals commonly form small, closely spaced stringers, gashes, or
short veinlets, lying mostly in the shear planes, as well as disseminations
throughout the schist. The size and the closeness of the spacing of the
veinlets in the schist usually determine the grade of the ore. Practically
the only gangue material in the replacement deposits is country rock.

DISTRIBUTION AND GEOLOGICAL FEATURES

The known mineral deposits are not uniformly distributed, but exhibit
a certain grouping. The grouping may be due to more prospecting in
certain parts and less in other parts; it may be the result of geological
causes; or it may be due in part to each of these factors. Most of the
deposits of the map-areas contain lead, zinc, silver, and some gold. A
smaller number contain copper and some gold. The copper deposits lie
in four areas separated and surrounded by deposits containing gold, silver,
lead, and zine.

A small group of copper-bearing deposits exists in the vicinity of the
Red Cliff mine, west of the Bear-American Creek valley. Another some-
what similar group of copper-bearing deposits occurs in the vicinity of the
Dalhousie mineral claims. This is also on the west side of Bear river and
the mineralized area may extend southward to include the holdings of the
Prince John Mining Company. A third group of copper deposits is on
Upper Bear river. The deposits of this group do not extend to high
elevations on the north side of Bear river, but extend above the George
copper deposits on the south side. -A fourth group of copper-bearing
deposits lies on Upper Bitter creek. This group includes the Olga, Sun-
shine, L. L. and H., Black Bear, and other mineral claims. Some of the
deposits within the area occupied by the fourth group contain lead and
zinc, but nearly all contain copper minerals. The deposits of the other
three groups are almost exclusively copper deposits. The copper-bearing
mineral in all the groups of deposits is chalcopyrite.

No convincing explanation of this segregation of the copper-bearing
deposits has been discovered. Rock types, structure, and mode of occur-
rence evidently have had little if any influence in causing segregation, as
the deposits occur as replacements in schistose rocks and in bedded forma-
tions, and as veins, and the copper-bearing areas have no structure peculiar
to themselves. The strikes of the deposits show considerable divergence.
Lacking any reasonable explanation whose soundness can be tested, it is
assumed that the grouping is related in some way to the mode of origin
of the deposits. The copper of each group of deposits may have been
derived from a source of mineral deposits locally rich in copper, in which
case the grouping is at once understandable. If the source were not locally
rich in copper the copper-bearing minerals may have been deposited at a
certain stage in the general period of ore deposition or at some more or
less fixed distance from the source. As copper-bearing minerals are in
general deposited closer to a source of ore deposits than silver, lead, or