Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-08-07
Ore Sill Going Down Below the Lowest
Workings Of the Eureka Con. Mine
Improvement in Quantity and Quality
of ths Ore in the Diamond and Excel
sior Mines as Depth is Attained
The Proportion Of Gold Increasing.
rHf FORMATIONS WHICH ARE oaf-BfAR
ING AND THOSE WHICH SEPARATE
THtM,
Adduced From the Records of the
n. n. Geological survey Of the
Fortieth Parallel aud the Personal
ueseareb of the Author.

rW,,usn for ne Sentinel" by N. n. Joseph
Mineral Hill, which occupies the north
ern slope OF Prospect Mountain. is com
posed of dolomitic limestone and granite.
. The Prospect Mountain qusrizite, which
thsre dipping to the northeast, forms the
footwsll OF the Ruby Hill lode. oyerlies
tbe granite aud bends around Prospect
Mountain to the east and west in the form
Of a horseshoe, trending on the east side
10 A point northeast OF and 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 quarternary just southwest
OF aud near the Prospect Mountain Tun-
uel, and still further south IL underiies the
Prospect Mountain limestone east OF and
near the Dug Out mine. On the east HANK
Of Prospect Mountain the quartzite dips
10 the east. The granite, which owes lite
exposure on the northerly slope OF Pros
peot Mountain 10 erosion, apparently dips
under the qusrtzite OF Buby Hill. Pre-
yious 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
quartzIts dips under the limestone oil the
Ruby Hill lode al 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 mar
row point or wedge between the Prospeci
Mountain quartzite and Pogonip lime
stone. On the northern end OF Ruby Hill
the limestone Ia cut of by fault fssure,
called the RUBY Hill fault" The width
OF the limestone zone OF Ruby Hill. ct the
surface. is from 800 TO 1000 feet; over
lying ID on the north are the Secret Can.
yon shale and the Hamburg limestone OF
Adams Hill. 0verlying the quartzite.
upon the east side OF Prospect Mountain.
10 q belt OF Hamburg limestone. which IL
doubtless connected at some depth beneath
the surface with that OF Adams Hill. In
tervening those two bodies At the surface,
over q space OF about 5000 feet. Is the
Pogonip limestone. which runs in q oon-
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 Ia a
band OF argilaoeous shale Identical In char.
aoter with that which overlies the north.
srn part OF the Ruby Hill lode. but known
n the Hamburg shale. Nearly all OF
THE ORE BODIES
Of considerable m magnitude and economic
value that we're discovered In Eureka Dis
trict up 10 the present time we're in the
Prospect Mountain and Hamburg lime
stone formations, OF the Csmbrian Age.
but valuable deposits OF ore have been
found In the Bullwhacker and Williams
nnts miaes. which are In ,he Pogonip
ames'one and quartz porptyry OF the 81
.uriah Age Very rich ore bAs been found
~ paying deposits in the mines OF New
10TH canyon, in Lone Mountain lime
stone, also OF the silurian Age. The Lone
fountain limestone 10 separated from the
rosonip limestone by the hard quartzite
Ieel OF Mcooys Ridge. Thia qusrtzite
oA'snds northward to Cariboo Hill and
sonthward TO Newark Valley.
The shales aud quartzites are substan.
tisily non-ore- bearing. In some places
the Prospect Mountain qnar,zite In Rnby
mn mas oeen imprsgnated with the ore
'oarins solutions, but II has nowhere been
found OF any economic value. Rbyolite.
species OF The porphyry class OF rocks,
s1eous sna non-ore bearing, Ia found in
dykes OF various dimensions in several
parts OF the district and frequently in di-
rect touch with the ore bearing strata
The solfasario action consequens upon its
eruption had probably much to do with
the ascending ore. bearing solutions. /, M,
with the actual deposition Of the ore.
Trending southerly from the end Of tbs
guartzite, on the east side Of Prospect
mountain. Is a belt Of Secret Canyon shale
which separates the Hambur limestone
.om the Prospect Mounts limestone
throughout the southern section OF the
district. The Prospect Mountain and
Hamburg limestones are identical in char.
scter in all but that the latter ia mors
silicious than the former. and il weather,
ioueher and breaks with sharper frac
ture. Returning to the
RUBY HILL FAULT.
tm nrst observed northward, Al The sur.
tace near The Albion mine, tshipr A Al.