MINEBK01107

• County: Gilpin
• Volume: 8
• Document: Inspectr
• Suffix: A

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- GEOLOGY. ~ ~~ 3
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~ There is no good geological survey of the district.
'The country rock consists of a gneissic or banded granite, cut
by a fissure vein system, having a general course ranging
from 2I.F, and S.'7, on one hand, and ~. and l7, on the other,
together ~Yith intrusive dykes of porphyry.
The vein filling consists of gold and silver bear-
ing iron pyrite and chalcopyrite oceuring in streaks (known
as smelting ore) and also disseainated through a quartzose
and feldspathic gringos, anor:n ~.s "mill ore".