Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-11-13
Eureka District.
DEEPLEVEL MINING
The Ruby Hill Fault Fissure.
ITS EXTENSION SOUTHWARK AND IN
FluExcs UPON the oaE-BEAUISc
STRUCTURE or RUBY HILL AND
PROSPECT MOUNTAIN.
Ore Still Going Down Below the Lowest
Workings Of the Eureka Con. Mine
improvement in Quantity and Quality
of the Ore in the Diamond and Excel
sior Mines as Depth is Attained
The Proportion Of Gold Increasing.
TINE FORMATIONS WHICH ARE 0af-BfAR'
ING AND THOSE WHICH SEPARATE
THEM
TINE FORMATIONS WHICH ARE oaf.BfAR'
ING AND THOSE WHICH SEPARATE
THEM.
Adduced From the Records of the
U. 3. Geological survey Of the
Forsieth Parallel and the Personal
Research Of the Author.

Wriaen for tie "Sentine" BY N. II. Joseph
Mineral Hill, which occupies the north
ern slope of Prospect Mountain. is com
posed OF dolomitic limestone and granite.
= The Prospects Mountain quartzite, which
there dipping to the northeast, forms the
footwsll of the Ruby Hill lode. overlies
the granite and bends around Prospect
Mountain to the east and west in the form
of 9 horseshoe, trending on the east eide
TO q point northeast OF aud near the Eu-
reks Tunnel and on the west side to an
other point extended westward from the
Grant mine. There il sinks beneath the
surface debris, but again appears above
the mountain quarternsry just southwest
Of and near the Prospect Mountain Tun-
mel, and still further south il underlies the
Prospect q tain limestone east Of and
near the Dug Out mine. On the east flank
Of Prospect Mountain the qusrtzite dips
to the east. The granite, which owes its
exposure on the northerly slope of Pros
pect Mountain TO erosion, apparently dipe
under the quartzite OF Buby Hill. Pre-
vious to the erosion, the great belt OF lime
stone Of Prospect Mountain and that
which constitutes the Ruby Hill lode were
presumably one and the same and formed
9 continuous body. The face Of the
quartzite dips under the limestone Of the
Ruby Hill lode at an average angle OF
about 40 degrees to che northeast. The
exposure OF this body Of limestone on the
surface extends over 1000 linear feet from
near the Albion shaft on the northwest.
where IL 10 covered BY the debris Of Spring
Valley 70 Q point southeast OF and beyond
the Jackson mine, where IL comes to q mar
row point or wedge between the Prospect
Mountain quArtzite and Pogonip lime
stone. On the northern end OF Ruby Hill
The limestone 10 cut of by a fault f~issure,
called the ''Ruby Hill fault" The width
Of the limestone zone Of Ruby Hill. st the
surface. Ia from 300 TO 1000 feet; over
lying II on the north are the Secret Can
Adams Hill. Overlying the quartzite,
upon the east side Of Prospect Mountain,
10 . belt Of Hamburg limestone. which IL
doubtless connected ~ some depth beneath
the surface with that Of Adams Hill. In
tervening those two bodies At the surface.
over . space OF about 5000 feet, Is the
Pogonip limestone. which RUM In q con-
tinuous bslt through the eastern portion
Of the district. from Diamond Valley,
north OF the Bullwhscksr mine TO Newark
Valley on the south. Overlying the Ham
burg limestone Of Prospect Mountain Is .
baud OF srgilaoeous shale Identical In char.
acter with that which overlies the north
srn part Of the Ruby Hill lode. but known
o. the Hamburg shale. Nearly All OF
THE ORE BODIES
OF considerable magnitude and economic
value that we're discovered In Eureka Dis
triot up 70 the present time were In the
Prospect Mountain and Hamburg lime
stone formations, Of the Cambrian Age,
but valuable deposits Of ore have been
found In the Bullwhscker aud Williams
burg mines. which are in the Pogonip
limestone and quartz porphyry Of the ST.
lurian Age. Very rich ore has been found
In paying deposits In the mines OF New
York Canyon, In Lone Mountain lime
stone, also Of the 6ilurian Age. The Lone
Mountain limestone is separated from the
Pogonip limestone by The hard quArtzite
reef of McCoy's Ridge. This quartzite
extends northwsrd to Cariboo Hill and
southwark to Newark Valley.
The shales and qusrtzites are substan-
TALLY non-ore- bearing. In some places
the Prospect Mountain quartzite In Ruby
Hill has been i~mpregnated with the ore
bearing solutions, but IL has nowhere been
found Of any economic value. Rhyolite,
. species Of the porphyry class Of rocks.
igneous and non-ore- bearing. is found in
dykes OF various dimensions In several
parts Of the district and frequently in di-
rect touch with the ore bearing strata.
The solfstsric action consequent upon its
eruption had probably much to do with
the ascending ore.besring solutions, II not
with the actual deposition Of the ore.
Trending s%outherly from the end Of the
quartzite, on the east side Of Prospect
IL . belt OF Secret Canyon shale,
which separates the Hamburg limestone
from the Prospect Mountain limestone
the southern section Of the
district. The Prospeos Mountain and
limestones are identical Ia char
acter in all but that the latter Is more
than the former, and il weathers
rougher and breaks with o sharper frsc-
surs. Returning to the
RUBY HILL FAULr
u il first observed northwsrd. At the sur-
lace near the Albion mine, taking an al
most uniform southeasterly course, with
10 average dip. underground, Of about 10
legrees TO the northeast. II passes near
he Richmond office and is plainly visible
lear the mouth OF . tunnel that Was for
nerly run to connect with the Bell shaft;
hence northeast Of the Eureka and
( K shafts 70 Q point between the Phenix
nd Jackson mines, where II bends around