Eureka weekly sentinel. [volume] (Eureka, Nev.) 1887-1902, 1897-12-04

Research OF the Author.
IWriaen for the Sentinel" by N. II. Joseph
Mineral Hill, which occupies the north
ern slope Of Prospect Mountain. is COM
posed Of dolomitic limestoneand granite.
4 The Prospects Mountain quartzite, which
there dipping to the northeast, forms the
footwsll Of the Ruby Hill lode. overlies
the granite and bends around Prospect
Mountain to the east and west in the form
OF q horseshoe, trending OF the east side
to q 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 il links beneath the
surface debris, but again appears above
the mountain quarternary 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. IN the east flank
OF Prospect Mountain the quartzise dips
to the east. The granite, which owes its
exposure en- the n~ortherly slope OF Pros
pect Mountain to erosion, apparently dips
under the qusrtzite 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 were
presumably one and the same and formed
Q 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 II 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 quartzite and Pogonip lime
stone. On the northern end OF Ruby Hill
the limestone lie cut off by . fault f~issure.
called the Ruby Hill fault" The width
Of the limestone zone Of Ruby Hill. ct the
surface. 10 from 800 70 1000 feet; over
lying 10 on the north are the Secret Can.
yon shale and the Hamburg limestone Of
Adams Hill. Overlying the quartzite.
upon the east side OF Prospect Mountain,
10 q bslt OF Hamburg limestone. which is
doubtless connected al some depth beneath
the surface with that Of Adams Hill. In
tsrvening those two bodies at the surface,
over . space OF about 5000 feet. ia the
Pogonip limestone, which rum In q CON-
tinuous belt through the eastern portion
Of the district. from Diamond Valley,
north OF the B~ullwhecker mine TO Newark
Valley on the south. O~verlying the Ham,
burg limestone Of Prospect Mountain 10 q
band Of argilaceous shsle Identical In CHAR
acter with that which ~overiies Me Meth.
ern part Of the Ruby Hill lode. but known
IS the Hamburg shale. Nearly all OF
THE ORE BODIES
OF considerable magnitude aud economic
value that we're discovered 10 Eureka Dis
trict up 10 the present time were 10 the
Prospect Mountain aud Hamburg lime
stone formations. OF the Cambrisn Age,
but valuable deposits Of ore have been
found In the ullwhscker and Williams
burg mines. which are In the Pogonip
limestone and quartz porphyry Of the ST.
lurisn 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 iiseetone by The hard quartzite
reef Of McOoy's Ridge. This qusrtzite
extends northwsrd to Cariboo Hill and
southwark 10 Newark Valley.
The shales aud quarszites are substsn.
TALLY non-ore- bearing. In some places
the Prospect Mountain quartzite in Ruby
Hill has been ~impregnated with the ore
bearing solutions, but 1t has nowhere been
found Of economic value. Rhyolite.
Q species Of the porphyry class Of rocks.
igneous and non-ore bearing, is found In
dykes OF various dimensions In several
parts OF the district and frequently in di-
rect touch with the ore bearing strata.
The solfatsric action consequent upon its
eruption had probably much to do wish
the ascending ore bearing solutions, IL not
with the actual deposition Of the ore.
Trending southerly from the end OF the
auartzite, on the east side OF Prospect
Mountain. Is 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 llmestonss are identical In char
scter In all but that the latter 10 more
silicious thar the former. and IL weathers
rougher and breaks with Q sharper frao-
ture. Returning TO the
RUBY L FAULT.
II is fret observed northward. 81 the sur
face near the Albion mine, taking an al
uniform southessterly course, with
average dip, underground, OF about 10
degrees 10 the northeast. 1t passes near
The Richmond Office and 10 plainly visible
near the mouth of Q tunnel that was for
merly run TO connect with the Bell shaft;
Ihenos northeast Of the Eureka and
Z K shafts 10 . point between the Phsnix
"a jashson mines, where u beads around