Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-11-27

~
ING AND THOSE WHICH SEPARATE
THEM.
Adduced From the Records of b
U. y. Geological survey of h
Fortfesh Parallel aud the Personal
Research of the Author.
IWraen for tie Sentinel by N. II. Joseph
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 the northeast, forms the
footwsll OF the Ruby Hill lode. oyerlies
the granite and bends around Prospect
Mountain to the east and west in the form
of a horseshoe, trending on the east side
to = point northeast OF and near the Eu-
reka Tunnel and on the west side to an
other point extended westward from The
Grant mine. There it sinks beneath the
surface debris, but again appears above
the mountain quarternary just southwest
OF aud near the Prospect Mountain Tun-
mel. and still further south it underlies the
Prospect Mountain limestone east Of and
near the Dug Out mine. On the east Hank
OF Prospect Mountain the quartzite dips
to the east. The granite, which owes its
Exposure on the northerly slope Of Pros.
pect Mountain TO erosion, apparently dips
under the qusrtzite OF Ruby Hill. Pre-
vious to the erosion, She great belt OF lime
stone Of Prospect Mountain and that
which constitute the Raby Hill lode we're
presumably one and the same and formed
o 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.
where 10 10 covered BY the debris Of Spring
Valley TO q point southeast Of and beyond
the Jackson mine. where il comes TO 8 mar
row point or wedge between the Prospect
Mountain quartzite aud Pogonip lime
stone. On the northern end Of Ruby Hill
called the 'Rnby Hill fault" The width
Of the limestone zone OF Ruby Hill. at the
surface, lie from 800 TO 1000 feet; over
lying 10 on the north are the Secret Can.
yon shale and the Hamburg limestone Of
Adams Hill. 0verIying the quArtzite.
upon the esst side Of Prospect Mountain,
is 4 belt Of Hamburg limestone. which IL
doubtless connected 81 some depth beneath
the surface with that OF Adams Hill. In
tervening those two bodies at the surface.
over 9 space OF about 5000 feet. Is the
Pogonip limestone, which runs in q con-
tinuous belt through the eastern portion
Of the district. from Diamond Valley,
north OF the Bullwhacker min 10 Newark
U.ttA- . a. go n.--tf-~ A. H.
burg limestone Of Prospect Mountain IL O
band Of argilaoeous shsle Identical 10 CHAR
scter with that which ~overlies the north
ern part OF the Rnby Hill lode, but known
as the Hamburg shale. Nearly all OF
THE ORE BODIES
OF considerable magnitude and economic
value that we're discovered In Eureka Dis-
trlot up 10 the present time were in the
Prospect Mountain and Hamburg lime
stone formations, OF the Cambrian Age,
bat valuable deposits Of ore have been
found in the Bullwhacker 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, 10 Lone Mountain lime
stone. also OF the Silurian Age. The Lone
Mountain limestone Is separated from the
Pogonip limestone by the hard qusrtzite
reef Of McCoy's Ridge. This qusrtzite
extends ~northward to Cariboo Hill and
southwark TO Newark Valley.
The shales and quarszites are substsn-
TALLY non .ore- bearing. In some places
the Prospect Mountain quartzite in Ruby
Hill has been i~mpregnated with the ore
bearing solutions, but 1t has nowhere been
found Of any economic value. Rhyolite.
. species Of the porphyry GLASS of rocks.
ignsous and non-ore bearing, is found in
dykes OF various dimensions in several
parts OF the district and frequently in d.
rect touch with the ore bearing strata.
The solfstaric action consequent upon is
eruption had probably much to do with
the ascending ore. bearing solutions, II not
with the actual deposition OF the ore.
Trendine southerly from the end Of the
quartzite, on the east side Of Prospect
Mountain, Ia q belt Of Secret Canyon shsle.
which separates the Hamburg limestone
from the Prospect Mountain limestone
throughout the southern section OF the
district. The Prospects Mountain and
Hamburg limestones are identical 10 char
acter in all but that the latter Is more
silicious than the former. and IL weathers
rougher and breaks with q sharper frac-
ture. Returning to the
RUBY HILL FAULT.
II 10 frat observed northwArd. Al the sur
face near the Albion mine, takiog an al
most uniform southessterly course, with
an average dip. underground, OF about 70
degrees to the northeast. IL 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 Pheoix
and jackson minss, whore 10 beads around