Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-07-24
Eureka District.
DEEPLEVEL MINING
The Ruby Hill Fault Fissure.
IT'S EXTENSION SOUTHWARK AND IN
FLUENcE UPON THE 0RE-BEARINc
STRUCTURE OF 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.
Tpr FORMATIONS WHICH ARE 0Rf-sfAR
ING AND THOSE WHICH SEPARATE
THEM.
Adduced From the Records of the
u. n. Geological survey of the
rortfeth Parallel ana the Personal
Research of she Author.

Research of the Author.
tWraen for ns Sentinel" ty N. N. Joseph }
Mineral Hill, which occupies the north
erp slope OF Prospect Mountain, ID com
posed OF dolomitic limestone aud granite.
! The Prospect Mountain quartztte. which
there dipping to she northeast, forms the
footwall OF the Ruby Hill lode. overlies
tbe granite and bends around Prospect
Mountain to the east and west in the form
of a horseshoe, trending on the east side
20 q point northeast OF and near the Eu-
reka Tunnel and on the west side 70 an
other point extended westward from The
Grant mine. There ID sinks beneath the
surface debris, but again appears above
the mountain quarterDary just southwest
Of and near the Prospect Mountain Tun-
mel, aud still further south II underlies the
Prospect Mountain limestone east OF ano
near the Dug Out mine. On the east Hank
Of Prospect Mountain the quartzite dips
10 the east. The granite, which owes Its
exposure on the northerly slope OF Pros.
peot Mountain 10 erosion. apparently dips
under the qusrtzite OF Ruby Hill. Pre-
vious 10 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
Q continuous body. The face OF the
qusrtzite dips under the limestone oil the
Ruby Hill lode at an average angle OF
about 40 degrees TO the 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 10 10 covered by the debris OF Spring
vallsy to point southeast OF and beyond
the Jackson mine, where II comes TO mar
All nlr.~ kat. he
Mountain qusrtzite and Pogonip lime
stone. On the northern end OF Ruby Hill
the limestone 10 cut of by fault hssure,
called the "Ruby Hill fault" The Width
OF the limestone zone Of Ruby Hill. at the
surface, 10 from 300 10 900 feet; over
lying ID on the north are the Secret Cam
yon shale and the Hamburg limestone Of
Adams Hill. overlying the quartzite.
upon the east side Of Prospect Mountain,
10 belt OF Hamburg Limestone. which IL
doubtless connected at some depth beneath
the surface with that OF Adams Hill. In
tervenipg those two bodies 81 the surface
over . space OF about 5000 feet. Is the
Pogonip limestone, which runs in q con.
tinuous belt through the eastern portion
OF the dlstrict. from Diamond Valley,
north Of the Bullwhacker mine to Newark
Valley on the south. Overlylng the Ham
burg limestone OF Prospect Mountain is 3
band OF argilaceous shale identical in char.
scter with that which overlies the north.
ern part Of the Ruby Hill lode. but known
as the Hamburg shale. Nearly all Of
THE ORE BODIES
OF considerable magnitude and economic
value that were discovered in Eureka Dis
trict up TO the present time we're in the
Prospect Mountain and Hamburg lime
stone formations. OF the Cambrisn Age,
but valuable deposits OF ore have been
,onnd In the Bullwhacker and Williams
oafs mines. which are In the Pogonip
imes"ne aud quartz porphyry OF the ST.
iut'sn age. Very rich ore has been found
In paying deposits In the mines of New
iork osnyon, In Lone Mountain lime
stone. Also OF the silurian Age. The Lone
Mountain limestone IL separated from the
fogonip Limestone by the hard ouartzite
reel OF McCoy's Ridge. This auartzite
extends northward to Csriboo Hin and
southwark to Newark Valley.
Inc shales and quartzites are subetan-
uAiiy hon'ore- bearing. In some places
the prospect Mountain quartzite in Ruby
hiii mas been impregnated with the ore
bearing solutions. but 1t has nowhere been
FOUND OF any economic value, Rhvolite
species OF the porphyry class OF rocks.
igneous and non.ore bearing, ia fonnd In
dykes OF various dimensions in several
parts OF the district and frequently in di-
rect touch with the ore bearing st,.,s
The soifataric action consequent upon its
eruption had probably much to do win
the ascending ore. bearing solutions. IL NO,
with the actual deposition OF the ore.
Trending southerly from the end OF she
qasrtzite, on the east side of Prosnac,
Mountain, Is belt Of Secret Canyon sbsls
which separates the Hamburg limsstons
from the Prospect Mountain limestons
throughout the southern section ~ ths
district. The Prospect Mountain ana
ham hamburg limessones are identical in char.
aoter In all but that the latter ia NOR
silicious than the former. ana n ws.tnsrs
rousher and breaks with a shsrnsr 1rso'
ture. Returning TO the f'' nav
RUBY HILL FAULT.
TVS nfst observed northward, a tbs sur-
race near the Albion mine, taxing g. 81.