The record-union., 1897-05-22
THE line OF CONTACT
In AuriterouS Formations An Old
Miners Advice.
Where Slate and Granite Come To.
gether-The Promise in the
Newcastle Region.

Especial Correspondence of Record-U n1on')
ST. HELENS orr, May ia lucky
forty-nine miner on being asked by an
emigrant who came to the mines a year
later, what were the best indications 1or
finding "pay dirt" answered, keep a
sharp look out for places where the slate
and granite come together. When you
find it, do most of your prospecting De-
low that line. You may not flnd pay
but you will find it rich in such places
Oftener than anywhere else.
The forty-niner had noted many ex-
ceptions to the rule. But by following
1t he had a buckskin purse well hlleo
with coarse gold and fine" Moving to
new mining districts in which neither
slate nor granite existed, like that on the
western slope of the Sierra Nevada
Mountains, our fortyniner still gave
close attention to places where two OH
ferent country rock formations come
together and with fair general results
Among miners this is now generally
known as the Zine of contact. no
eral per cent of paying quartz chlmHeys
have been found along these lines OIL
contact. There are many exceptions 10
the rule. Paying quartz lodes nave
probably been discovered in about all OF
the primitive rocks, both within the con-
tact line. and miles away from it. How,
ever, when an old miner finds one OF
these lines of contact running through
a highly auriferous range, and compara-
lively unprospected,, he will most prop
ably inquire why a point so favoraple
for finding valuable quartz chimneys
has been neglected. If he takes lively
interest in all that pertains to mining
discoveries, the old-time fire may burst
out anew, and much time be devoted to
learning all about what had been done
there in times gone by, and speculatlng
on probable future.
In going East from Sacramento on the
Central Pacific Railroad, the first line of
contact claiming our attention is crossed
by the railroad track about one-fourth
of mile above the town of Newcastle,
in Placer County. For various reasons
this is one that will claim good deal of
our attention. 1t is within the boundar-
les of rich and extensive placer min
ing district mined out years ago. Many
quartz lodes have been opened and are
now being worked in that district with
the successes and failures usual in all
mining operations. Very little attention
has been given to prosecuting for lodes
For distance of more than two miles
careful examination failed to show that
any prosecuting had been done on this
line of contact in prospecting for blind
lodes or deposits. Near the line of con-
tact both the slate and the the granite
become cofter and are just such forma-
tons as old experienced miners would
say, that a quartz lode could live in
hot here show
many quartz stringers, some of which
carry gold.
The fact of this line of contact remain
ing, almost unprospected, is no evidence
for or against the existence of valuable
quartz chimneys within that line of
contact. Pay chimneys do not often
crop out above the surface.
Grain fields vineyards and fruit orch
ards flourish above the contact line in
many places, and on the ridge above
Newcastle it is covered by old river bed
gravel and lava cap that breaks off at
the head of Secret Ravine and disap-
pears, completely eroded
Many of the landowners in the vicin-
fly of Newcastle show a liberal spirit in
permitting prospecting on their grounds,
if done, as it should be, working no
the owner Sacramentans who feel like
risking little money in prospecting for
quartz chimneys could not find another
place with so many advantages as that
near Newcastle l do not mean the old
time prospecting. Bed rock tunnels,
and shafts that were sure to strike the
dip of the lode two hundred feet below
the surface" That was all dead work,
and almost ALWAYS dead loss
A good deal of ground can be suffi-
ciently well prospected for a compara-
lively small outlay of money. One dis
covered quartz chimney would repay the
outlay thousand fold. But, says Pru-
dence, rs not prospecting and mining a
gamble?" Well. yes; it does come near
being so sometimes. But it is a gamble
by which millions are won from mother