Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-06-26
Eureka District.
DEEPLEVEL MINING
The Ruby Mill Fault fissure.
IT'S EXTENSION SOUTHWARK AND IN
FluENcE UPON THE 0RE-BEARINc
STRUCTURE OF RUBY MILL AND
PROSPECT MOUNTAIN.
Ore Still Going Down Below the Lowest
Workings Of the Eureka Con. Mine
Improyementin Quantity and Quality
OF the Ore inthe Diamond and Excel
sior Mines is Depth is Attained
The PrOpOrtim OF Gold Increasing.
TINE FORMATIONS WHICH ARE 0Rf.BfAR'
inc AND THlsf WHICH SEPARATE
THEM.
Adduced From the Records of the
u. n. Geological survey of the
Fortfeth PaniieI aud the Personal
Research ofthe Author.

FoFtfeth PAritfeI and the FeFsohai
Research ofthe Author.
fwrinen for ne Sentinel" BY N. II. Joseph J
Mineral Hill, which occupies the north
eru slope OF Propec. Mountain, is com
uosed OF dolomiic limestone and granite.
: The Prospect fountain quartzite, which
there dipping te the northeast, forms the
footwsll OF the Ruby Hill lode. overlies
tbe granite and bends around Prospect
Mountain 20 theesst and west In the form
of q horseshoe, rending on the east side
20 A point nortlBsst OF and near the Eu.
reka Tunnel ami on the west side 10 an
other point extaded westward from the
Grant mine. There IL sinks beneath the
surface debris, put again appears above
the mountain qnrternary just southwest
Of and near the Prospect Mountain Tun-
uel, and still furher south IL underlies the
Prospect Mountain limestone east OF and
near the Dug Oh mine. On the east Hank
OF Prospect Mountain the quartzite dips
20 the east. TIL, granite, which owes its
exposure on thsnortherly slope OF Pros
pect Mountain &C erosion, apparently dips
under the quartsite OF Ruby Hill. Pre-
vious 10 the eros on, 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 uider the limestone OF the
Ruby Hill lode at an average angle oi
about 40 degrees 20 the northeast. The
exposure OF this body OF limestone on the
surface extends ever 900 linear feet from
near the Albion shaft on the northwest,
where ID IL covered by the debris OF Spring
Valley 10 . pointsoutheast Of and beyond
the Jackson mine, where 10 comes TO q mar
row point or wedge between the Prospect
Mountain quartsite and Pogonip lime
stone. On the northern end OF Ruby Hill
the limestone 10 sut off by q fault fssure,
called the "Ruby Hill fault" The width
OF the lines tone zone OF Ruby Hill. at the
surface, Is from 800 TO 1000 feet; over
lying II on the north are the Secret Can.
yon shale and thu Hamburg limestone OF
Adams Hill. 0verIying the quartzite,
upon the east side of Prospect Mountain,
IL belt OF Hamburg limestone. which is
doubtless connected 81 some depth beneath
The surface with that OF Adams Hill. In
fervening those two bodies at she surface,
over Q space o, about 5000 feet. Is the
Pogonip limestone, which runs in con.
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 is q
band OF srgilaceous shale identical In CHAR,
soser with that which overlies the north
srn part OF the Ruby Hill lode. but known
a. the Hamburg shale. Nearly all OF
THE ORE BODIES
OF considerable magnitude and economic
value that we're discovered in Eureka Dis
trict up TO the present time were in tht
Prospect Mountain and Hamburg lime
stone formations, OF the Csmbrian Age
Das valuable deposits OF ore have beer
iound In the Bullwhacker and Williams
onrs mines. whioh are in she PogoniI
nmss'one ano quartz porphyry OF abe 81
,urisn age. Very rich ore has been found
~ paying deposits in the mines OF New
IolA canyon, In Lone Mountain lime
ssone, also OF the siiurian Age. The Lon,
Mountain limestone is sopsrsted from m
Pogonip limestone by the hard ou.rtzit,
reef OF McCoy's Ridge. Thk ouartzit
extends northwsrd to Cariboo hin an,
southwark to Newark Valley.
The shales and quartzites are substsn
tally non-ore- bearing. In some nlace,
the Prospect Mountain quartzite in Rnh,
Hill has been i'm pregnated with the ora
bearing solutions, but II has nowhere bae,
found OF any ecoiiomic value. Rbyolite
species OF the porphyry class OF rocks
igneous and non-ore bearing. is found /,
dykes OF various dimensions in severs
parts OF the district and frequently in di
rect touch with the ore bearing straits
The solfatario action consequent npon n
eruption had pr obably much to do wit
the ascending ore.bearing solutions, il NO
with the actual deposition OF the ore.
Trending southerly from the end Of sh
qnartzite, on the east side Of Prospee
Mountain. is belt Of Secret Canyon shal.
which separates the Hsmburg limsston
from the Prospect Mountain limestop
throughout the southern section Of N
district. The Prospect Mountain an
Hamburg limestones are |, 1entical in cha,
aoter in all but that the latter is NOR
silicious than the former. and 1t weathe,
Tougher and breaks With sharper fra,
turs. Returning to the
RrBY HILL FAT lit.
.sM nrst obser we'd northw ard, al the an,
'soe near the Albion min }, taking an d