Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-11-20
aaeeAIp a District.
PUBLISHED Ever
@sPLEVEL MINING
sATURDAr
The Ruby Hill Fault Fissure.
ITS EXTENSION SOUTHWARK, AND IN
IFlUsHcE UPON THE 0RE-BEAsISc
STRUCTURE OF RUBY HILL AND
PROSPECT MOUNTAIN.
Ore Still Going Down Below the Lowest
Workings of the Eureka Con. Mint
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 oRf-BfAa-
ING AND THOSE WHICH SEPARATE
THEM.
Adduced From the Records of the
TINE FORMATIONS WHICH ARE oRf-BfAa
ING AND THOSE WHICH SEPARATE
THEM.
Adduced From the Records Of u
u. n. Geological survey Of n
Forsteth Parallel and the Personal
Research Of the Author.

Written for he Sentinel BY N. H.. Joss.4
Mineral Hill, which occupies the north
ern slope of Prospect Mountain. is com
posed OF dolomitic limestone and granite.
. The Prospect Mountain quartzite, which
there dipping to she northeast, forms the
footwall OF the Ruby Hill lode. overlies
The granite and bends around Prospect
Mountain TO tie east and west in the form
Of . horseshoe, trending on the east side
to q point northeast Of and near the Eu-
reks Tunnel and on the west side 20 an
other point extended westward from the
Grant mine. There ID 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 Mountain 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 dips
under the quartzite Of Ruby Hill. Pre-
vious TO the erosion, the great belt OF lime
stone OF Prospect Mountain and that
which constitutes the Ruby Hill lode we're
presumably one and the same and formed
q continuous body. The face Of the
qusrtzite dips under the limestone OF the
Ruby Hill lode OF an average angle OF
about 40 degrees to the northeast. The
exposure Of this body of limestone on the
surface extends over 4 900 linear feet from
near the Albion shaft on the northwest.
where ID 10 covered by the debris Of Spring
Valley 70 . point southeast OF and beyond
the Jackson mine. where IL comes to q mar
row point or wedge between the Prospect
Mountain qusrszite and Pogonip lime
stone. On the northern end Of Ruby Hill
the limestone is cut of by q fault dssure,
called the "Ruby Hill fault" The width
Of the limestone zone OF Ruby Hill. ct the
surface, is from 300 TO 1000 feet; over
lying ID on the north are the Secret Cam
yon shale and the Hamburg limestone Of
Adams Hill. Oyerlying the quartzite,
upon the east side OF Prospect Mountain,
IL a belt Of Hamburg limestone. which is
doubtless connected 81 some depth beneath
the surface with that OF Adams Hill. In
tsrvening those two bodies At the surface.
over . space Of about 5000 feet. is the
Pogonip limestone, which runs In q pom
tinuous belt through the eastern portion
Of the district. from Diamond Valley,
north Of the Bullwhacker mine to Newark
Valley on the south. Overlying the Ham,
burg limestone Of Prospect Mountain IL q
baud OF argilsceous shale identical 10 char.
acter with that which o~verlies the north
ern part Of the Ruby Hill lode. but known
IS the Hamburg shsle. Nesrly all Of
TIE ri 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 Csmbrian Age,
but valuable deposits OF ore have been
found in the Bull whscker and 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 Silurian Age. The Lone
Mountain limestone is separated from the
Pogonip limestone by the hard quartzite
reef Of McCoy's Ridge. This quartzite
extends northward TO Cariboo Hill and
southwark TO Newark Valley.
The shales and quartzites are substsn-
TALLY non.ore bearing. In some places
the Prospect Mountain qusrtzite In Ruby
Hill has been impregnated with the ore
bearing solutions, but IL has nowhere been
found Of any economic value. Rhyolite,
0 species Of the porphyry class OF rocks,
igneous and MOI bearing, ia found In
dykes OF various dimensions 10 several
parts Of the district and frequently in d.
rect touch with the ore bearing strata.
The solfataric action consequent upon its
eruption had probably much to do with
the ascending ore bearing solutions, II not
with the actual deposition Of the ore.
Trending southerly from the end Of the
quartzite, on the east side Of Prospect
Mountain, is q belt Of Secret Canyon shale,
which separates the Hamburg limestone
from the Prospect Mountain limestone
throughout the southern section OF the
district. The Prospect Mountain and
Hamburg limestonss are identical in char
acter in all but that the latter is more
silicious than the former. and it weathers
rougher and breaks with Q sharper frac-
ture. Returning 10 the
RUBY III FAULT
II IL frst observed n~orthward. at the sur
face near the Albion mine. taking an AL
most uniform southessterly course, with
an average dip. underground, OF sbout 10
degrees 10 the northeast. It passes near
the Richmond Office and is plainly visible
near the mouth Of Q tunnel that was for
merly run to connect with the Bell shaft;
thence northeast Of the Eureka and
K K shafts 70 . point between the Phenix
and Jsohson mines, where 10 bends around