Gold Hill daily news. [volume] (Gold Hill, N.T. [Nev.]) 1863-1882, 1875-10-20
CHANGES n the ooSDrrioss OF
THE COylsrOCk LODE.


Mr.. @. +. Becker OF the California
University. read q paper before the
Academy Of Sciences In San Francisco
last Monday evening. upon tho Com
stock Lode and an alleged change in its
dip and the character Of its east wall.
which Is Of great interest TO mining
men. rs well rs all interested In the
mines Of this section. Space precludes
tho reproduction Of the entire article.
but VIC give the most important points.
After alluding TO the well-known fact
that the west wall OF the Comstock Is q
continuation Of Mount Davidson and in
character sysnits. while to . certain
depth the east or hanging wall Is porphy-
~. or. moro accurately. trachyhc
greensboro. Mr.. Becker assumes that ut
q depth Of fifteen hundred feet In the
Virginia mines the assure which
to that depth has been found lying be-
tween the syenite and everything porphy-
ry changes ita dip and enters the syen-
ito, and that thereafter to tho lowest
depths attained both the east and west
walls are of this character Of rock.
Without specializing upon the probable
results Of this fact. II. indeed. u DO q
fact. We reproduce the clOsins portions
Of Mr.. Bscksr's paper. which include
the observations made By him and upon
which the assumed change in the for
nation and dip Of tho Comstock lode Is
predicatsd. These observations were
begun in May last and extended into
August, and from them Mr.. Becker as
serts that ''the lower workings Of the
mines In Virginia City havo reached the
| point ut which the assure passes from
the contact surface between the sysnite
Of Mount Davidson and the country
porphyry (propylits) into the underly-
| ing syenits." This statement Mr..
Becker bases upon tho following OBJ
served facts:
In tho Chollar-P otosi mine the north
and south drift on tho 1500-foot level
shows q wall Of syenits for . distance Of
several hundred feet. which 10 consid-
cred In the mine 10 be the true east
wall. The rock is very solid in charao-
ter. exhibiting nons Of the evidences Of
dynamical action commonly seen In in
ciudsd rock. or horses. The wall In 40
companisd by clay seam. In the Hale
4 Norcross an unbroksn Of syenite.
lying east OF the vein, IL exposed 10 q
thickness Of ITO feet by the cross-cut
from the station on the 2100-foot level.
| The cross-cut on the 220O-foot station
had advanced on August Goth to q dis
tance OF 100 feet from the shaft. For
the whole Of this distance the drift was
in solid syenits, and the face showed no
| signs Of the proximity OF the vein. The
bottom Of tho incline. 1880 feet below
the surface. AZ well as its whole lower
portion for q distance Of several hundred
feet, Is in unbroken syenite. The sye-
mite IL said to have been struck a. high
~ the l200-foot level. The dip Of the
vein Is rapidly increasing In the lower
levels Of this mine. which accounts for
the distance Of the incline stations from
tho east or hanging wall Of the lode.
In the Savage tho incline shaft has
boon from at least rs high as tho 1900
foot level to its present depth Of 2.2S0
feet, In solid syenits. From the 2l0O-
foot station about 400 fsot OF syenite
was passed. through before the vein was
reached. and on tho 2200-foot level q
still greater thickness. This sysnits Ii
plainly the same body struck In the
Hale L Nsrcroxs. GOO feet distant. and
In the Chollar- Potosi. 1000 feet further
south. Tho dip Of the vein in tho Saw
age 10 rapidly increasing in tho lower
levels.
In the Gould & Curry the cost wall Is
Inaccessible. but a large body Of syenite
10 found within the vein, and the main
''horse" rock Of the mine in lis lower
levels 1850 and LOCO fest) Ia sysnits.
Although an inspection Of the east
country rock In this mine would be
much more satisfactory than an In.
ference, II seems 10 mo fair TO conclude
that had the comparatively soft and brit
tie porpylits prophyry formed the east
wall. the main included rock would have
been Of that species.
In the Best and Belchsr. and the Con-
solidated Virginia too. the east clay.
seams have not been pierced for fear OF
tapping q water body, but the included
rock ON the l500-foot and l5G5.foot lev
els Of the Consolidated Virginia, whore
not too much desomposed for recogni-
ton. Ia generally syenite.
In the California the third cross-cut
on the l500-foot level has been run into
east country. which proves to DO sysnits
Of the solidsst description. This wall
seems TO be very nearly perpendicular.
In the Ophir. syenits has boon struck
at several points on the ltG5 foot level
to the east Of tho vein. and neal the
south line has been penetrated to .
depth Of three hundred feet. On tho
rlln "a -. -. a.. all ~. ....sla