Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-07-17
Ore Still Going Down Below the Lowest
Workings OF the Eureka Con. Nine.
improvement in Quantity and Quality
Of the Ore in the Diamond and Excel.
dor Mines as Depth is Attained---
The Proportion OF Gold Increasing.
Tus FORMATIONS WHICH ARE 0RE.stAR
ING AND THOSE Which SEPARATE
THEM.
Adduced From the Records OF the
u. n. Geological survey of ths
Forsieth Parallel aud the Personal
Rescnrch OF the Author.

,Wriiten for as seniiHei" ty N. ". Joseph.
Mineral Hill, which occupies the north
ern slope OF Prospect Mountain. is com
posed Of dolomitic limestone and granite.
: The Prospect Mountain qusrtzite, which
there dipping TO the northeast. forms the
footwsll OF the Ruby Hill lode. overlies
the granite and bends around Prospect
Mountain to the esst and west in the form
of a horseshoe, trending on the east side
70 q point northeast OF and near the Eu-
reks Tunnel and ON the west side 10 an
other point extended westward from the
Grant mine. There ID sinks beneath the
surface debris, but again appears above
the mountain quarternary just southwest
OF and near the Prospect Mountain Tnn-
mel, and still further south IL underlies the
Prospect Mount tain limestone east OF and
near the Dug Out mine. On the east flank
OF Prospect Mountain the quartzite dips
70 the east. The granite, which owes its
exposure on the northerly slope OF Pros
pSct Mountain 20 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 huby Hill lode we're
presumably one and she same and formed
. 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 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,
whore II 10 covered BY the debris OF Spring
Valley 70 point southeast OF and beyond
tho Jackson mine. where IL comes TO mar
row point or wedge between the Prospect
AL Ala .nA In tts.za
stone. On the northern end OF Ruby Hill
called the "Ruby Hill fault" The width
OF the limestone zone OF Ruby Hill. at the
surface. is from 500 10 1000 feet; over
lying 10 on the north are the Secret Can.
you shale and the Hamburg limestone Of
Adams Hill. 0verlying the quArtzite.
upon the east side OF Prospect Mountain.
is belt Of Hamburg limestone. which is
doubtless connected at some depth beneath
the surface with that OF Adams Hill. In
tervening those two bodies at the surface,
over o space OF about 8, 1000 feet, Ia the
Pogonip limestone, which runs in q con
tinuous belt through the eastern portion
OF the district. from Diamond Valley,
north OF the Bullwhacker mine 10 Newark
Valley on the south. 0verlying the Ham
burg limestone OF Prospect Mountain Ia a
band OF argilsoeous shale identical In char.
acter 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
vi considerable magnitude and economic
value that we're discovered In Eureka Dis
triet up 70 the present time were in the
Prospect Mountain and Hamburg lime
stone formations, OF the Cambrisn Age,
eas valuable deposits OF ore have been
ioaaa IN the Bullwhacker aud Williams
ns mines, which are in the Pogonip
in.;. o,'oae and quartz porphyry OF the 81
u'isn age. Very rich ore has been found
psy,ng deposits In the mines Of New
. .A canyon, In Lone Mountain lime
Mo ons, a,so OF 'he silurian Age. The Lone
poa"asA nmes'ooe 10 separated from the
Fosonip limestone by the hard ou.rtzite
reef Of McCoy's Ridge. This dns.,-i.s
extends northward to Cariboo Hin ana
southwark to Newark Valley.
The shales and quartzitss ara auhs,sn.
italy non-ore-beAring. In some nlsca.
tne Prospect Mountain quartzi.e In Rnhv
niil mas been impregnated with the orc
bearing solutions, but ID has nowhere hasr
found OF any economic value, Rbvol;ta
= species OF the porphyry class OF ro.t.
isneous and non-ore- bearing, is found In
dykes Of various dimensions IN savav., !,
parts OF the district and frequently in Al"
rect touch with the ore bearing s,rs,s
Tne solfatario action consequens upon n.
eruption had probably much to do wiz
she ascending e-bearing solutions. n mo,
WIN the actual deposition Of the ore.
Trending southerly from the end OF ,b,
guArtzite, on the east side OF Prosnec,
mountain, Ia belt Of Secret Canvon .hala
which separates the Hamburg iinss,on.
from the Prospect Mountain iimss.ons
throughout the southern section Of tbs
district. The Prospect Mountain .nd
hsmonrg iimestones are identical in char,
so!ei IN all but that the latter ia NOR,
siiicious than the former. and IA weasnsr.
suusner and breaks with a sharper frsc
f. RUBY HILL FAULT.
leoN near iha Aihinn s.slaa IN. ~ ~.