The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1897-08-01
The Mother Lode

+ II IS mfsconception to consider the mother
ioue simply as single and continuous ledge
OF quartz running for 200 miles through the
country 1t is rather a line of assure at the
1ootof the sierra Nevadas filed partly with
dy kes Of porphyry and ruffs of quartz, in ter
sected by masses of black states; and often
ruins of pre-existing rocks, immersed more or
less completely in crystaIlized quartz the en-.
tire ventricular masses showing every sign OF
metamorphism in q high degree, and the
walls of the adjoining country rock abound
ing in the crevices or cracks of an original
cooling of the mass, and filed with stringers
and feeders of quartz encased in films of shin
ing black slate (slicken sides), loaded with
sulph urets and often abundant in free gold.
This paralI ell group of veins, from it's eastern
hanging wall to the west, is of very irregular
width, sometimes only showing single: line
of groupings an d at others spreading to sew.
eral hundred feet 1t is accompanied by a
series of ehimneys as vents at very irregular
distances apart on its course, through which
imm ense masses of pure quartz have reached
the surface, and which usually lie ct steep
angle longltudinallY with the fssure. "
These chimneys have generally been the
pay shoots of the mines. The gold which they
brought to the surface in the days of their
activity has long since been scattered over the
face of the country by the denudatlon to
which it has been subjected from that long ago
period when its lofty SUBMITS were first
broken up and buried beneath the. old gravel
and lava beds down to the present, where
these beds and the underlying rocks have
again been chiseled out by the rivers and
streams of our times. - 1899 .:''
There are two chief lines Of collaborating
rocks to the mother lode, the cas- tern and the
western. The eastern rises between walls Of
black slate, and carries films and sheets of
slate into. the mass, giving striped or
ribboned appearance: The second, a short
distance west. follows stratum of magne-
SUM rock, characterized byits rusty on tcrops.
In this We recognize the green's tone (diorite
sehis tos) dykes. T1e general strike of the
states when not disturbed by local eruptions is
north and south and dips nearly or quite YER
teal The greater portion of these rocks are.
however, to be- classed among the eruptives.
They are in many cases greatly decomposed,
and in the induced schistose structure are
often mistaken for metamorphized sediments.
This schistose structure has generally north
and south direction: AS before mentioned
slate forms the western part of the lode form
ing belt from few hundred yards to more
than mile in width. 1t is: cut by many
dykes of fine greensboro, and OF hers of horn
blend and quartz porphyry. s.;.@+.
The quartz veins are formed both in the
slate and in the contact with the eruptive and
inclosed in them. The diorite shistos varying
to taIcose schist, forms a large portion OF
the system. The greensboro has been derived
from massive crystalline rock by pressure
and resultant decompositicn; quartz veins
are very numerous in it, some of hem belong
ing to the east and west SYSTEM float qnartz
is abundant and all the gulches. show signs of
having been sluiced. 49,
+. South of Sonora the greensboro appears
more in the form of dykes; between these are
long narrow arms of metamorphic rocks.
chiefly silicious schists. In.these schists are
most OF the veins on which are located the
Rawnide, App, Golden Rule and Jumper
mines - -. -.
+ The gold-bearing deposits may be divided
into two general classes; to one class belongs
the Rawhide mine, while to the other belong
| the white quartz veins formed after the usual:
manner; best illustrated by the Kennedy and
Golden Gate mines, a which may be prop
erly*con sIdered ais deposited by replacement
/ and characterized by. the even istribution of
the gold and small, well formed crystals of
T. All the material of the lode obtains iron
suiphides scattered through its minute cubes
and calcife in small PARTICLES. =
There are seve raj parallel veins from ten to
500 feet apart. course north, Is degrees east;
wit dip f76 degrees east, and from five to
Thirty feet:wlde between porphyritic hanging
and slate foot walls The quartz is of ribbon
structure in terstratified with black slate, car
l ry Ing from to per cent sulp huTets, mostly ::
iron. which concentrate from So % to $500 per
ton.7. The: VEINS are true assures and deep
seated, and am in doubt il they can be bot =
toned at q depth of 5000 feet "A heavy foot
and hanging wall gouge composed OF pulver-
FiZed quartz snd,;sia highly mineraliZed &C
companies. the veins, and in no place have!I
noticed the freezing of the veins 10 the walls.
In my opinion there is not q better district in
the world or one that: affords more induce
ments for investment, of capital in legitimate
mining than the mother lode of California.
IL: :: $500. ID. Y. BROWNE. .