San Benito County CA Archives History - Books .....Chapter II Mineralogy 1893
************************************************
Copyright.  All rights reserved.
http://www.rootsweb.com/~usgenweb/copyright.htm
http://www.rootsweb.com/~usgenweb/ca/cafiles.htm
************************************************

File contributed for use in USGenWeb Archives by:
Joy Fisher sdgenweb@yahoo.com September 17, 2006, 4:39 am

Book Title: Memorial And Biographical History Of The Coast Counties Of Central California.

CHAPTER II.
MINERALOGY.

THE following brief notes are gleaned from the reports of the State mineralogist
for the years 1888 and 1890, and are of interest in this connection. While this
(San Benito) county is regarded as essentially agricultural, yet to an observer
it appears to possess mineral resources of equal importance to others in the
State. The Mount Diablo range has proved of incalculable wealth in its coal,
quicksilver, copper, chrome, petroleum, ochre and antimony; and in the Gabilan
range, lime, gypsum and iron are present.

  Nearly one-half of this country, including most of its arable land, lies in
the San Benito valley; and the mountains bordering on this valley are
grass-covered to their summits.

  There is a little timber on the Gabilan mountains, but not much of any kind
elsewhere in the county.

  The San Benito river and its tributaries, together with the Pajaro on its
northern boundary, take in the entire hydrographic system of the county.

QUICKSILVER-NEW IDRIA.

  As is well known, the New Idria quicksilver mines rank among the most famous
in the world. They are situated in the western end of Vallecitos valley, on the
southeastern borders of San Benito county, in the portion acquired from Fresno.
These mines were discovered about the year 1852 or 1853. Work was first
commenced upon a deposit of chromic iron at the top of the mountain near the
boundary line between Monterey and this part of San Benito county, then a
portion of Fresno, under the impression that it was silver ore.

  Through assays made by the old padres of Monterey cinnabar was discovered
where New Idria now stands, and about 1854 or, 1855 the New Idria mine was located.

  The lode is a large body of ore, in some places having been worked to a width
of two hundred feet. The vein has a general pitch toward the south of from
forty-five to sixty degrees.

  The foot-wall is a "silico-argillaceous" slate. In the lower workings there is
a dark-colored clay, from a few inches to a foot or more in thickness between it
and the vein matter. The hanging-wall is a similar slate, but rather more
compact in structure, often presenting a slicken-side surface toward the vein,
and being easily broken into glossy laminae.

  The vein matter varies in different parts of the workings. The better grade of
ore has been found in the highest and western portion of the mountain. Most of
the gangue is hard and siliceous, but at some times it is slaty or of a clayey
nature, often containing much oxide of iron. The ore richest in mineral is
usually found toward the hanging-wall. Below the Day tunnel, as far as has yet
been explored, the vein becomes poorer, and the gangue, which is at first
siliceous or slaty, changes to a sandy character. The New Idria mines are all in
the northeastern slope of the mountain, which rises to the height of about 1,500
feet above the reduction works, which are situated at its base; the summit of
the mountain is between 4,000 and 5,000 feet above sea level. There are over one
and one-half miles of tunneling in the New Idria mines, not including the huge
chambers which have been dug out in the heart of the mountain.

  The highest workings are the oldest, and are at the ridge of the mountain.
These consist of an incline running down upon the vein to the Sleeman tunnel.
This tunnel, which is about 900 feet above the reduction works, runs south into
the mountain for a distance of 700 feet, and was made in 1859. About 300 feet
lower down is the Myers' tunnel, which was commenced in 1859 and finished in
1860. This penetrates the mountain to a distance of about 1,000 feet. It is from
this tunnel and the Sleeman that the highest grade of ore and the largest
quantities have been taken.

  The ore here also appears to be the most ferruginous, and at one point, where
a small stream of water drips from the roof, there are to be seen  stalactites
of sulphate of iron.

Upon the walls of all the upper workings, fibrous gypsum forms in beautiful
tufts like glossy moss. Some 200 feet lower down, and | about 600 feet above the
reduction works, is the Day tunnel. This also was started in 1859, and
penetrated the mountain to a depth of 1,500 feet. This tunnel has "been
prolonged outwardly by timber, in order to allow dumping facilities for the work
above, that otherwise would have covered up the mouth of the Day tunnel. The
dump of the Myers' tunnel above has accumulated and slid-den down upon the
prolongation until there are over 100 feet at the commencement of the Day tunnel
running under this waste rock.

  All these workings, from the top of the mountain to the Day tunnel, constitute
the upper portion of the mine, and are connected with each other by various
tunnels and upraises. About one hundred feet above the reduction works, and 500
feet below the Day tunnel, is the Bell tunnel, or lower workings, about 4,000
feet in length. This tunnel is timbered almost throughout its entire length with
closely set timbers, there being over 3,000 sets, with lagging both on the roof
and sides. Each set requires a log twenty feet long and ten inches in diameter.
The temperature in this tunnel is high, and the atmosphere damp and oppressive.
Whether it is the effect of the heat and moisture, or some gaseous exhalation of
the formation is not known; but the timbers decay in an unusually short time,
and two men are kept constantly employed in replacing the old ones by new.

This rapid decay is more marked during sultry weather, when the draft in the
tunnel is almost nil and the atmosphere oppressive. Timbers immersed in water,
or those which are kept constantly wet by seepage, do not seem to be so
affected. Dry, seasoned wood lasts the longest. Timbers, after having stood in
place for only thirty-six hours, have' accumulated a mildew one inch in thickness.

  The furnaces of the New Idria mines are of the same style as those in use at
the Idria, Austria, being square, about thirty feet in height, ten feet in
width, and twelve feet in length. The furnace is fed at the top by means of a
drop hopper, at the rate of one ton per hour, and holding twenty-four tons when
full. There are employed two men to each shift of twelve hours on the furnace,
and fifty men in and about the mines. The fuel used is almost entirely manzanita
and oak, which is delivered at the furnace at $6.50 per cord, one cord being
consumed every twenty-four hours.

  A condensed history of the Mexican grant, "La Panoche Grande," on which these
"New Idria quicksilver mines" were discovered, may be found in another part of
this work.

  The enormous output of these mines, which are claimed only by a squatter's
title (by a company composed largely of foreigners or of persons living in
foreign countries) has enabled the claimants of the mines to contest the title
to the ranche for thirty-five years, notwithstanding the fact that said title
has been pronounced genuine, and that a patent was ordered issued therefor
nearly thirty years ago. The case is one of the most anomalous in the history of
this country.

ANTIMONY.

  Antimony is found in the McLeod mining district, which is situated some
fourteen miles northeast of Hollister, the county seat. The mines, which were
discovered in 1861 are situated on the northern and western slopes of Antimony
mountain, which rises to the height of over 3,000 feet above sea level.

  The backbone and higher portions of Antimony mountain are formed of diorite,
syenite and serpentine rocks, which penetrate a sandstone at its base, and
argillaceous slates upon its slope, in which the principal mineral-bearing veins
are chiefly located.

  The Shriver and Ambrose are the principal antimony mines which have been
worked. The ore from the latter contains 38 per cent metallic antimony, which
sells in San Francisco at $55 per ton. The former was bonded in 1890 for
$35,000, the bonders paying $5 a ton on all antimony ore taken out.

COAL.

  Valuable discoveries of coal have been made in numerous localities in San
Benito county; as in the New Idria, Vallecitos and other districts. A variety of
coal resembling jet has been found near Elkhorn, and good coal prospects are to
be found on the Oienega Gabilan (Hawk swamp or marsh) ranche. The coal-bearing
formations at Emmett were worked as early as 1878. The Bart coal mine, situated
about 1,000 feet above the roadway north of Emmett, is developed by an incline
and a cross-cut at the upper working and a 100-foot tunnel lower down. The
incline commences on a small vein about three inches wide of black, lustrous
lignite, much of which shows a woody structure. The working itself is in clay
slate, of which both hanging and foot walls are composed. The pitch of the vein
is to the northwest at an angle of about twenty degrees. At one place, about
halfway down the main incline, the vein pinches out, but reappears shortly
before reaching the crosscut, which is at a depth of about thirty feet. The main
incline is continued for about sixty feet farther, but has now caved. The
cross-cut is continued to the west as an incline and follow the vein, which is
from two to six inches in thickness. This cross-cut was filled with water to
within a distance of thirty feet from the main incline. At the water's edge the
vein is about six inches in diameter. Eighty feet below the mouth of the upper
working is a tunnel, which has been started to connect with the incline and
drain the upper workings of water. In this tunnel slate or conglomerate is
encountered with small crystals of gypsum on the cleavage surface of the hard
slate passed through.

  On Panoche creek, also upon the east side of the roadway, to the west of the
well of the California Central Oil Company, some work has been done in the way
of development. There appear to be three coal veins separated by strata of
light-colored sandstone. These veins, the largest of which are over four feet
thick, are composed of shale interstratified with seams of coal.

  On the Ashurst ranch in the Vallecitos, are several coal prospects,—-probably
a continuation of the coal measures which crop out on the east side of the road
near the central oil well. The formation is sandstone, occasionally
interstratified with shale; in the upper portion of the hills is a fossiliferous
sandstone containing Pecten and other shells. The coal measures are exposed at
two places on this ranch in the channels of the creek. At one point the vein is
about eighteen inches wide and dips a little to the east of south at an angle of
about forty-five degrees. It is composed of black fissile shale mixed with
carbonaceous matter and rests upon a stratum of clay about six inches thick,
showing carbonized plant remains; above the coal is a stratum of highly colored
clay. In another portion of the same creek other veins are exposed. Crossing the
New Idria section of the coast range, which here rises to the height of about
4,000 feet above sea level, the watershed of San Benito creek is reached.

  On the western slope of the mountains, about three miles northeast of the
creek, a large vein of coal is exposed. This vein was uncovered by a landslide,
which occurred during wet weather in 1885. It is on the northern side of a
ravine in the western slope of the New Idria section of the coast range. The
vein of about six feet in thickness is exposed along its strike for a distance
of 100 feet, and dips to the north at an angle of about forty degrees. The
hanging-wall is a brownish shale, eighteen inches thick, containing gypsum.
Above this wall are about eight inches of sandstone, stained with yellow
ocherous impregnations, which is overlaid by a stratum of hard, ferruginous
sandstone, a foot or more in thickness: and from that to the top of the bluff,
probably 200 feet, the formation is a gray, friable sandstone, interstratified
with pebbles, sometimes increasing to the size of small boulders and strata of
hard, iron-stained sandstone a few inches in thickness. The coal appears to be
of good quality, and resembles that in the Vallecitos. These croppiugs are
partly on Government land and partly on land belonging to the Southern Pacific
Railway Company. There is no doubt that a careful investigation will discover
similar formations in other spurs and hills on the western slope of the same
mountain.

PETROLEUM.

  The oil-bearing strata of San Benito county have as yet been only partially
prospected. A well has been bored by the California Central Oil Company in the
Vallecitos mining district. The road to this district from Panoche lies through
Grizzly canon, a treeless, desolate section of country, where the erosive action
of the winter's storms, cloudbursts, and atmospheric agencies, are strikingly
demonstrated in the precipitous banks of the dry watercourses, the gaping
crevasses in the alluvial soil, and the grotesque shapes into which the
sandstones and softer rocks are worn.

  The works of the oil company are situated about eight miles from Panoche. Work
was commenced here in 1886, and suspended during the following year. It is said
that the company expended $20,000 on their works, and that their well, which was
sunk to a depth of 400 feet, has partially caved. The boring was through a
light-colored sandstone, which became quite white toward the bottom, where a
small quantity of oil was struck.

  In the canon to the north is a spring of dark-colored oil, and oil also seeps
through the bed and bank of the creek at several places, as well as on the
Ashurst ranch in this district.

LIME.

  Lime is extensively manufactured at Cienega, in the Gabiian mountains, sixteen
miles south of Hollister; and excellent limestone also occurs in the Twitchell
range, nine miles west of Hollister, where it has been burnt in pot kilns. The
Twitchell kilns furnished the lime used in building the Hollister courthouse.

  The geological formation of the neighborhood is entirely metamorphic, the
rocks of the vicinity being principally granitoid, together with altered
limestone. The latter is a  beautiful crystalline variety, which yields an
excellent quality of lime, and is in great demand, especially for plastering and
brick work. The strata of limestone in the quarry appear much disturbed,
pitching southwest at an angle of sixty-five degrees upon the west side of the
quarry, and upon the north side to the northwest at an angle of forty-five
degrees. Before reaching the line, a body of decomposed grantic rock was cut
through for a few feet, and the clays and shales which separated the strata of
limestone previous to the metamorphic action, are strangely diversified, some
being chalky, others slaty, while a few feet off they are granitic. The hill, at
the foot of which the quarry is situated, rises to the height of over 2,000 feet
above sea level, being about 700 feet above the quarry. The limestone crops out
at various places among the chemisal almost to the summit.

  Further to the northwest granitic rocks make their appearance in a ridge
running north-northeast by south-southwest, and a short distance up the canon
from precipitous cliffs. Immediately at the point of contact between the ridge
of granitic rocks and the limestone, is a spring of water and an appearance of
vein matter. One great peculiarity of the granitic rocks of this locality is
their singular stratified appearance.

  A few yards to the south of the quarry are the (perpetual) lime kilns. These
kilns are upright, tapering toward the top, thirty-one feet high, and having a
circumference at the level of the fireplaces, of forty-two feet with an inside
diameter of four and one-half feet at the same level. The charging floor is
twenty-one feet above the firing floor, where two fireplaces heat the kiln; the
point of discharge is ten feet lower down. The kilns are two in number and have
a capacity of about fifty barrels each twenty-four hours, each kiln consuming
two and one-half cords of wood. The wood used is pitch pine, costing $2.50 per
cord delivered at the kiln, and the wages paid to the seven employes is from $50
to $60 per month. The lime can be delivered at the Tres Pinos railroad station
for $1.30 per barrel.

  A copper mine called the Antelope has been opened about fourteen miles east of
Emmett, on the east side of the Panoche section of the coast range.

  Chromite is found near New Idria, and in many other localities, but all at
present are too far from railroad communication to make the deposits of
commercial value.

  There is a large body of hematite near Cienega, and gypsum is found in the
south end of the county.


Additional Comments:
Extracted from:

Memorial and Biographical History of the Coast Counties of Central California.

Illustrated.

Containing a History of this Important Section of the Pacific Coast from the
Earliest Period of its Discovery to the Present Time, together with Glimpses of
its Auspicious Future; Illustrations and Full-Page Portraits of some of its
Eminent Men, and Biographical Mention of many of its Pioneers, and Prominent
Citizens of To-day.



HENRY D. BARROWS,
Editor of the Historical Department.

LUTHER A. INGERSOLL,
Editor of the Biographical Department.

"A people that take no pride in the noble achievements of remote ancestors will
never achieve anything worthy to be remembered with pride by remote
descendants."-Macaulay.


CHICAGO: THE LEWIS PUBLISHING COMPANY.
1893.


File at: http://ftp.rootsweb.com/pub/usgenweb/ca/sanbenito/history/1893/memorial/chapteri438nms.txt

This file has been created by a form at http://www.genrecords.net/cafiles/

File size: 17.9 Kb