At the time of my visit the mine had been opened to a depth of 180 feet, by two working shafts. The total length opened on the vein is 300 feet. Two levels have been run and work was in progress on the third. The main ore body lies in the center of the workings, and extends downward in the dip of the veins. The ore milled averaged 5 per cent of tin oxide, though large portions, as before stated, are very high grade. The company has also prospected Cajalco Hill by tunnel and open cuts, and one or more of the veins south by shafts. At the time of my visit two of Husband’s pneumatic stamps were in operation. They weigh 900 pounds each, and drop one hundred and thirty-five times per minute.
South and southeast of the works are many bunchy veins of the black tin gangue. They often carry considerable iron. They extend, generally nearly parallel, in a northeast and southwest direction. Some appear as mere bunches on the surface. These veins closely resemble the main vein at Cajalco Hill, and are due to the same action, and it has been supposed that many of them will be found to carry tin, though it is not present on the surface. About 2 miles south the granite is replaced by a banded feldspar porphyry. This cuts off the tourmaline veins. The granite about the works, and especially toward the contact with the porphyry, is cut by many dikes of a fine-grained granite, having an excess of quartz and feldspar. Associated with the porphyry are strata of metamorphic rocks, of a hard, dark, quartzose character. A quarter of a mile northwest of the mine is a bunch-like outcrop of porphyry, carrying silver and copper carbonate. The black veins outcrop for adistance of 2 miles northwest from the mine, extending into the porphyry, which replaces the granite in that direction. The granite extends eastward for many miles.
The general geological features which obtain here are: A semi-circular area of granite over 2 miles in diameter, surrounded on the northwest and south by porphyries and joined on the east to a great body of granitic rocks extending indefinitely in that direction. Around the border of this granite protuberance are many dikes of a fine-grained granite. Cutting through the granite in a northeast and southwest direction are the black tourmaline veins, which form the gangue of the tin ore when it is present.
Tin occurs here under conditions different from any other known deposit. Tin veins are almost always found in granitic formations, but such an extensively developed tourmaline veinstone is remarkable. The direction of the fissure system shown here is an uncommon one in California. The veinstone, together with the associated metals, has probably resulted from a process of sublimation along lines of fracture, removing those portions of the granite easily affected, over a large area, as at Cajalco Hill, and in the immediate contact completely replacing it with the massive aggregate of minute tourmaline crystals.
Thanks are due to the manager, Captain Harris, for the facility freely afforded me for examining the mine, the works, and the country about.
North of South Riverside the Tertiary beds dip at a small angle to the north. The Santa Ana River has cut its course through the hills at the northern end of the Santa Ana Mountains. No outcrop of the metamorphic rocks appears in the cañon. The Tertiary strata no longer dip toward the west, but in the Chino hills north of the river show a great anticlinal arch. Along the south side of the river the beds dip 70° northeast; farther west, near the heart of the range, they dip 60° southwest, strike north 30° west. Near the upper end of the cañon there are fault lines dipping toward the range, which show an elevation of the hanging wall. Bedrock Cañon is the first large one which opens to the Santa Ana River from the western slope of the mountains. Opposite the mouth of this cañon the greatest amount of water appears in the bed of the river, indicating the presence of hard rock only a little distance below. Coal veins are located near the head of this cañon, one 700, the other one 1,300 feet above the river. They dip only a few degrees to the southwest. They are exposed on cliffs facing the mountains to the northeast. Below them are very hard sandstones carrying fossils, probably Cretaceous. One prospect shows a number of seams within a width of 8 feet. The widest is 29 inches, the others much smaller. The other prospects show only one 39-inch seam. Their position, lying so flat high on the mountains, indicates an uplift without great disturbance, while the gypsum mines farther down on the flank of the mountains dip at a high angle to the southeast. It may be that all of the coal deposits of the western slope of the Santa Ana Mountains belong to the Cretaceous, and have been greatly separated by faulting and folding. A deposit of white, granular gypsum has been opened in Gypsum Cañon, 2 miles south of the river. The beds have a thickness of 8 or 10 feet. At one spot a large mass of crystalline dolomite was found. The deposits run with the strata, north and south, and dip west 60°. As we approach Olive, the few croppings seen still dip south or southwest, but at a less angle. South of the mouth ofSilverado Cañon a line of hills extends north and south, bordering the Santa Ana Plain. The western portion of these hills is formed of basalt considerably decomposed. The basalt varies from scoriaceous to fine-grained and compact. Its eastern edge was seen to rest on Miocene sandstones, and it dips west at a small angle, perhaps 10°. The lava seems to have been squeezed up in fissures, judging from the way in which it outcrops. Its greatest elevation is 800 feet. At some places the sandstones, where not covered with lava, have been silicified, turned to quartzite, or rendered granitic in appearance. This may be due to an intrusive neck of lava, or more probably to the action of thermal springs.
An interesting fold of the Tertiary strata was observed at the entrance of Santiago Cañon. The sandstones and conglomerates on the eastern side dip to the northeast at an angle of 30°, while those on the west side dip in the opposite direction. The valley has been eroded in the summit of an anticlinal. The rocks of the eastern side rise again against the side of the mountains, thus forming a synclinal. Up the cañon the sandstones on the west maintain a southwest dip of 45° to 50°, and strike north 40° west. The cañon finally leaves the anticlinal, and the rocks dip southwest on both sides. Toward the summit of the hill, north of the Harris Coal Mine, the dip increases to 70°, but on the top they turn so that the strata lie horizontal. Here they consist of clay shale. The strata at the coal mine swing around, and one mile northeast they strike north and south and dip west. This hill seems to form the southern termination of the anticlinal ridge north of Santiago Cañon. Southeast of this point there is a simple monoclinal fold or slope away from the older rocks of the high mountains. There has apparently been a fault extending northwest in this anticlinal ridge, bringing up the clay shales which farther south were shown to belong to the Cretaceous. Harris Coal Mine shows a seam 18 inches wide, shale forming the foot wall and sandstone the upper. There is a fault of 200 feet cutting this coal seam. The sandstone at the mouth of Silverado Cañon dips south 30°, forming bold cliffs. A half mile up the cañon there are heavy beds of clay shale inclosed in the sandstone. Cretaceous fossils appear in the shales, as well as in a coarse sandstone which underlies them. This sandstone is replaced by conglomerates near the contact with the underlying Metamorphic Series. The sandstone rises to a height of 2,500 feet, with bold, almost perpendicular cliffs facing the mountains. Portions of the sandstone containing the fossils are often very much hardened.
The first crystalline rocks met are dark and fine grained, with traces of bowlder-like inclusions, and are evidently eruptive tuffs. Above these are green, dioritic rocks. These intrusives are followed for several miles by sandstone and shale, in which the stratification is often obliterated. In other places thin layers of sandstone and shale are wonderfully contorted. The dip is at a high angle either east or west. In the vicinity of the old Silverado Camp there are dikes and bunches of a green dioritic rock. The mines in the Silverado district are again being developed to some extent. The mineral belt is about 2 miles wide, and extends nearly north and south. The country is formed to a great extent of dikes of greenish to blackish rocks, often showing distinct hornblende crystals. The dip of the metamorphic rocks is east about 45°. There is one main mineral vein located, beginning about a milenorth of Silverado, and extending in a southerly direction for 7 or 8 miles. The Quincy Mine is one of the most northern ones. The vein has a width of 2 feet; the ore, silver-bearing galena in a calcite gangue. It carries but little base metal of any kind. The ore has a peculiar appearance, the galena being distributed through the gangue in little leafy crystals or aggregates. The fissure is well defined and regular, with a pale green syenitic rock on the hanging wall, and a dark diorite on the foot wall. This hanging wall rock weathers to a light gray color, producing a rock known as porphyry among the miners. South of this mine a side vein carries much antimony. The Quincy has been opened along a length of 500 feet. The ore is quite uniform, producing one eighth in concentrates. The Quincy camp has an elevation of 2,300 feet. South of Silverado Cañon, in Silver and Pine Cañons, a great amount of work was done during the former excitement. The sides of the steep, rocky cañons are fairly honey-combed with tunnels, which were undertaken without sufficient prospecting, and, of course, never struck anything. The New York Mine spent much money, but did not prove a success. West is the Princess, and farther still, about 1,200 feet above the cañon, is the Blue Light Mine, on which much work has been done and rich ore taken out. The mines south of the cañon are in a feldspathic rock, which weathers white. It is undoubtedly an intrusive porphyry, for traces of feldspar crystals are to be seen. The mines are characterized by a large amount of zinc-blende, iron pyrites, and not a large percentage of lead, making them more difficult to reduce. The porphyry is mineralized in many places where no traces of the precious metals occur. Litigation and poor management seem to be the chief factors in stopping work in this district. Though some of the ore runs into hundreds of dollars to the ton, the most of it is medium to low grade.
About a mile and a half down the cañon from the old Silver Post Office, and in a cañon coming in from the south, is a cropping of dark, somewhat argillaceous limestone inclosed in shales. The limestone does not seem to have been highly metamorphosed, yet the fossils which it contains are almost obliterated. The faint impressions are those of coral stems, stromatopora, and some other low forms of life. Half a mile farther down the cañon is a cropping of brecciated marble. At many points, particularly on the north side of the cañon, there are great masses of apparently conglomeritic character, but with a crystalline structure. The matrix has a green to brown color, and in it are imbedded pebbles of the same degree of fineness, but often distinguished by much brighter red, purple, and green colors. In this cañon, as in others of this range, the water holds much lime in solution, and extensive tufas are frequently to be seen. The basal members of the Cretaceous at the mouth of Silverado Cañon consist of conglomerates passing up into sandstone, and those into shales; dip 55° away from the mountains in the highest ridge, but in the course of a quarter of a mile becoming much less. The change in dip is very sharp, giving the appearance of a fault.
A cañon which enters Silverado Cañon from the northeast near its mouth was followed up nearly to its head for the purpose of investigating some limestone outcrops. The first outcrop in this cañon is the usual dark porphyry. Beyond this the stream has cut a deep cañon through an immense conglomerate of porphyritic and quartzose pebbles. The porphyritic pebbles are dioritic and part red and black porphyries.Some of them are similar to dikes farther up the mountains. Through this great conglomerate bed there are dikes of black porphyry, with pale feldspar. Tufaceous porphyries form a large part of these dikes. The base is purple and the pebbles light green, or the reverse. These conglomeritic porphyries differ from the great beds of sedimentary origin, in having all the pebbles of a uniform character with a crystalline matrix. The sedimentary beds contain pebbles of all sizes and description, in a matrix of small pebbles or coarse sand. Farther up the cañon the great body of the rock is crushed shale and black to gray sandstone; dip vertical, inclining most generally to the east, strike north and south. Two miles up the cañon is a dike of diorite porphyrite, coarse in the middle and fine on the edges. Four miles up is a stratum of gray limestone. More outcrops appear on the north side of the cañon, but whether they belong to the same stratum or different cannot be told, on account of the crushing undergone. These deposits are bunchy, swelling in one case to a width of 100 feet. It is not crystalline. The color is from black to gray. It contains fine specimens of a bivalve shell, and faint traces of corals and univalve shells. These beds are said to extend to the summit, and undoubtedly further examination would reveal more fossils. Several specimens were sent to the National Museum and pronounced Carboniferous in age. We have here, then, the first announcement of the age of the Santa Ana range. This range stands in such intimate relation to the granite and crystalline schists farther south, that an approximate determination of the latter is made possible. Professor Whitney and others following him have classified this range as Cretaceous. Their grounds are utterly untenable stratigraphically, but this discovery of Carboniferous fossils makes the evidence of greater age certain.
On the eastern side of the range, near its northern end, the sandstones were observed to be silicified, being filled with a network of quartz veinlets, exactly similar to the silicification of the metamorphic rocks of the Coast Range proper.
The lowest Cretaceous beds are between Silverado and Williams Cañons, but the fossils are very similar to those generally found through the Cretaceous of this region. The lowest beds are a duplicate of those seen at the mouth of the Silverado Cañon, though apparently a thousand feet lower in the series. Between the two beds there is another conglomerate stratum, carrying bowlders different from any seen in the Santa Ana Mountains. Many of the porphyry bowlders in the basal Cretaceous conglomerates resemble the porphyry about Temescal. The Santa Clara Coal Mine, at the mouth of Silverado Cañon, is undoubtedly in strata of Cretaceous age, though no fossils are found in the strata above till the Miocene is reached. Up the Santiago Cañon as far as Madame Modjeska’s place, the fossils are chiefly confined to the eastern side of the cañon, but the character, dip, and strike of the strata on both sides are the same. The Cretaceous is separated from the metamorphics by a line of cross cañons. The highest portions of the Cretaceous terminate in a line of hills with sharp eastern escarpments.
Shrewsbury Cañon comes in just below Modjeska’s. After passing the Cretaceous, through which the cañon has cut, the Metamorphic Series was seen to consist of slates and sandstones, followed by light-colored granitic rocks, chiefly hornblende and triclinic feldspar. The metamorphic rocks generally dip to the east.
A mile above Modjeska’s the Santiago Cañon cuts through bold cliffs of Cretaceous sandstones and conglomerates, and higher up still has eroded a cañon in the Metamorphic Series. The cliffs, a little back from the stream, rise probably 1,000 feet. Sandstone belonging to the Metamorphic Series outcrops in the cañon for some distance, and is followed by conglomeritic porphyries, containing purple and red bowlders. In some places the inclusions are angular. These rocks are extensively developed about the Santiago Mines and higher up in the mountains.
Just below the Alma Mine, on its western side, the creek has cut through dikes of diorite, which are coarse in the center and fine on the edges. On the hill south of the Alma Mine the diorite is on the opposite or eastern side of the vein. Although the exposures are poor, all the crystalline rocks have the character of intrusives. No blending into the metamorphic rocks has been noticed. About 3 miles up Shrewsbury Cañon several claims are located on the southern continuation of the veins of the Silverado district. Near the head of Santiago Cañon these again appear well defined, and considerable active work was going on here at the time of my visit. The veins here have a direction a little east of south, dipping to the east somewhat less than 45°. It appears that the mineral belt follows a certain line, generally quite regular, without any particular reference to the dikes and bunches of intrusives scattered irregularly here and there. The fissure system has taken a comparatively regular line and the walls may or may not be intrusive. The Alma Mine, the northern claim of the Santiago Silver Mining Company, has been worked by the former operators in a very irregular manner. The veins and stringers as far as exposed lie wholly in the crushed quartzose argillites. A tunnel is now being run to open what is supposed to be the main vein, several hundred feet farther east, and which has syenite on the hanging wall. Other tunnels are being run along the creek, one near a body of granitoid rocks, others in slate or quartzite. The ore is a leafy galena, arranged often in narrow bands with the crystalline orientation different in alternating bands. Sometimes it occurs in the form of large solid bunches. Thus far the ore deposits have been found quite irregular, but it is thought that the main body has not yet been reached. Very little base metal is present. South, on the hill, the Morrow claims have been bonded by the same company and are being opened. On the summit of the hill diorite lies on the eastern side of the veins. Down the southern slope the veins lie wholly in metamorphic rocks; the foot wall being more silicious, the hanging argillaceous. The mineralized portion has a width of 20 feet. A small vein occurs in the upper side, and a heavier one, sometimes reaching 3 feet, on the foot wall. There are occasional stringers in the crushed portions between. The gangue is calcite, with some quartz, all mixed with the broken clayey slates. More zinc-blende and iron pyrites are found here, also a little antimony. In the Alma Mine the richest galena is very fine, and sometimes resembles antimonial ores.
South of these mines, toward Trabuco Cañon, another claim is being worked. South of the Trabuco the conglomerates hide the lode, except at one spot, where it appears and has been worked. The Cretaceous formation grows lower as the Trabuco is approached, and does not appear prominent south of it. In all probability it is covered by the Tertiary, for the elevation and consequent erosion have not been as great in this direction.
ByW. H. Storms, Assistant in the Field.
No portion of California has more diversified mineral wealth than the county of San Bernardino. Although its area is comprised largely of rugged mountains and desert waste, yet this county is a producer of gold, silver, copper, lead, and tin, and contains mines of zinc, iron, and manganese, besides deposits of borax, salt, soda, baryta, gypsum, sulphur, onyx, marble, asbestos, and structural material, granite, and sandstone of great beauty and value. Within its borders are found a wide range of geological formations from Paleozoic (if not Archæan) to Tertiary, and a great variety of rocks of igneous origin.
The mines are scattered all over its thousands of square miles of territory, and have already added millions of dollars to the wealth of the State and the world. Many of its mines are of phenomenal richness, and were it not for the expense and extreme difficulty attending transportation in the desert, San Bernardino County would undoubtedly take first place in adding to the mineral wealth of California. The largest and most productive section in the county at present is
No region affords better opportunities for the study of a certain class of ore deposits occurring in eruptive and fragmental rocks than may be found in the Calico District. The mines, condemned at first, came quickly to the front nevertheless, and have for the past twelve years been steady producers of silver bullion. The district is situated 6 miles north of the Atlantic and Pacific Railroad, the nearest station being Daggett.
The geology of the Calico Mountains at first sight looks simple enough, but a more thorough investigation quickly convinced me that there were structural problems to be studied of more than passing importance, as they seemed to have a bearing upon the extent of the ore deposits. The most complex region is that immediately about the town of Calico, in the vicinity of the mines. The balance of the mountain area is more simple.
In a general way the Calico uplift consists of a core of massive rhyolite, overlying which are heavy deposits of light-colored breccia and tufa. Along the flanks of the range, and in some places extending well up into the mountains, are accumulations of undoubted sedimentary origin, sandstone, sandy shales, and argillaceous rocks, which, with some local exceptions, dip away from the central mass on all sides toward the desert plain. While in the district I made some notes on the general geological features, but not having sufficient time at mydisposal to complete these investigations, I have determined not to present my views until I have had an opportunity to investigate the region more carefully.
Subsequent to the uplift of these mountains, erosion has carved deep cañons and removed great mountain masses. The central area is now entirely denuded, whereas it was at one time covered with from 100 to 200 feet of tufa and upward of 1,000 feet of sedimentary strata. Not only have these more recent accumulations been removed, but a large amount of the hard, dense liparite has also been disintegrated and carried away by the violent storms which are characteristic of the desert. Faults are very numerous throughout that portion of the mountains lying along the south side of the range. They extend for at least 10 miles in an easterly and westerly direction. The mines occur along this faulted zone.
The rocks of the region are a violet to brown rhyolite, often porphyritic; green, yellow, and white tufa; yellowish and greenish breccia; a greenish gray, fine-grained rock, which has been called hornblende andesite by Mr. Lindgren, and a yellowish or buff to light gray felsitic rock, which may be either rhyolite or an older felsite. It is extremely difficult to distinguish between these rocks, even with the aid of thin sections under the microscope. I think, however, upon structural grounds, that I may call the rock felsite. As this is one of the important questions upon which I have not thoroughly satisfied myself, it will be left until such time as I have opportunity to make the necessary investigation.
The formation of the ore deposits in the Calico District has been a subject of much discussion, and the question has received the closest study and thorough investigation. In my opinion, the ore deposits were formed through the agency of percolating waters carrying mineral solutions, which deposited their contents along fault planes and in certain zones of the country rock, where its brecciated and crushed state offered superior conditions for the deposit of the silver ores and the accompanying baryta. That all of these ore deposits have a common genesis I do not doubt, whether they occur in the liparite, in the tufa, or in the “mud” overhanging country rock, as is the case at the Bismarck, Humbug, Waterloo, and some other mines. The form of the deposits differ somewhat, it is true, for we find the reticulated veins in the King Mine; the segregated deposits in the Odessa and Waterloo; the fissures in the Langtry, in West Calico, and the impregnated deposit in the Humbug. However, all the deposits of the district, of whatever form, I believe are due to a common cause, having been deposited in their various forms from mineral-bearing solutions which derived their contents from the neighboring eruptive rocks (the liparites and tufas), part of the material doubtless arising from great depth, and a portion coming from the adjacent inclosing rocks by what is known as lateral secretion. It is almost an impossibility to find in the Calico region a piece of rock that does not contain more or less silver, from a fraction of an ounce per ton upward.
The phenomena of ore deposition was very thoroughly investigated by Messrs. Louis Janin, E.M., John Hays Hammond, E.M., Ross E. Browne, E.M., and Wm. Irelan, Jr., State Mineralogist, at the time ofthe lawsuit of John S. Doe vs. Waterloo Mining Company. These gentlemen all agreed upon the origin of the ore deposits, and their opinions coincide with my own and are in accordance with the ideas expressed above. The wide difference in the size and form of the many ore bodies does not in any manner conflict with the theory that in each instance the primary cause of the deposit was a fracturing and crushing of the rock masses and the subsequent infiltration of mineral solutions, which precipitated their contents in the zones and crevices thus prepared for their reception.
SKETCH SHOWINGDISTRIBUTION OF ORE ON THE SURFACE IN THESILVER KING MINEAS IT OCCURS BETWEEN THE FAULT PLANESCALICO MINING DISTRICTSAN BERNARDINO CO. CAL.COPIED FROM EXHIBIT“R”COURT RECORDS IN THE SUIT OFJOHN S. DOE VS. WATERLOO MINING CO.
SKETCH SHOWINGDISTRIBUTION OF ORE ON THE SURFACE IN THESILVER KING MINEAS IT OCCURS BETWEEN THE FAULT PLANESCALICO MINING DISTRICTSAN BERNARDINO CO. CAL.COPIED FROM EXHIBIT“R”COURT RECORDS IN THE SUIT OFJOHN S. DOE VS. WATERLOO MINING CO.
In the Silver King Mine occurs a perfect network of veins, concerning which Mr. Hammond testified: “At the time of the uplifting of the liparite, or at some subsequent time, a fault occurred, which separated a wedge-like mass of liparite from the main mountain mass, and this fault plane was generally conceded to be what might be termed the foot wall of the mineral belt, or zone, or lode. Contemporaneously with this faulting a second fault occurred, which separated the overlying brown tufa from the liparite, which fissure forms the overhanging wall of the mineral deposits of the Silver King Mine. At the same time cross fissures were formed in the liparite mass between the two main fissures. Thus there was a main fissure or plane of contact between the brown tufa and the liparite, and a similar fault plane between the segment of liparite broken off and the main mass of the mountain. Between these two main fissures, and throughout the whole mass of this segment of liparite were innumerable fissures, some similar and equal in size to the main fissures, and others forming a finer system of fissures and cracks, extending through the rocks in all directions, leaving it in a broken and disintegrated, and in many places an almost pulverized condition. Although these finer fissures generally had a parallelism with the two main fissures bounding this segment of rock, yet, in many places, these finer seams or fissures run in every direction through the rock, forming a network, or reticulated mass. The mineral-bearing waters have deposited throughout this mass, from wall to wall, the minerals now found within this zone in the form of baryta, carrying silver. The finding of baryta in the shattered planes of the liparite, which is entirely foreign to the rock itself, is sufficient evidence that a crack or space must have existed prior to its deposition, from the solutions which penetrated this broken zone of a once massive rock formation.”
CROSS SECTIONS OFSILVER KING MINETAKEN FROM COURT RECORDS IN SUIT OFJOHN S. DOE VS. WATERLOO MINING CO.
CROSS SECTIONS OFSILVER KING MINETAKEN FROM COURT RECORDS IN SUIT OFJOHN S. DOE VS. WATERLOO MINING CO.
REPORT STATE MINERALOGISTWM.IRELAN, JR.STATE MINERALOGIST.VERTICAL CROSS SECTIONSHOWING THE FORMATION OF THESILVER KING LODECALICO MINING DISTRICT.SAN BERNARDINO CO. CAL.COPIED FROM EXHIBIT “P”COURT RECORDS OFJOHN S. DOEVS.WATERLOO MINING CO.
REPORT STATE MINERALOGISTWM.IRELAN, JR.STATE MINERALOGIST.VERTICAL CROSS SECTIONSHOWING THE FORMATION OF THESILVER KING LODECALICO MINING DISTRICT.SAN BERNARDINO CO. CAL.COPIED FROM EXHIBIT “P”COURT RECORDS OFJOHN S. DOEVS.WATERLOO MINING CO.
STATE MINERALOGIST’S REPORTWM.IRELAN, JR.STATE MINERALOGISTSKETCH MAP SHOWING THE FAULT SYSTEMOF THE CALICO MINING DISTRICTPARTLY TAKEN FROM A MAPBYW. LINDGREN, E.M.BYW. H. STORMS, E.M.ASSISTANT IN THE FIELD.
STATE MINERALOGIST’S REPORTWM.IRELAN, JR.STATE MINERALOGISTSKETCH MAP SHOWING THE FAULT SYSTEMOF THE CALICO MINING DISTRICTPARTLY TAKEN FROM A MAPBYW. LINDGREN, E.M.BYW. H. STORMS, E.M.ASSISTANT IN THE FIELD.
The Odessa Mine offers good illustrations of impregnated masses, as does also the Waterloo. In each of these mines, as in many others, the ore bodies are found in bunches or pockets, varying from little deposits of nominal value to great ore chambers containing thousands of tons of pay rock. In these cases, as at the King Mine, a system of faulting planes marks the general strike of a mineral-bearing zone or lode, but the great rock masses of tufa, in which these ore bodies occur (and also of sandstone in the Waterloo), are quite loose and porous in texture, and undoubtedly the ore bodies in these mines resulted partially, at least, from the impregnation of the rock with the mineral solutions which found an easy passage along the fault planes that had cut the rocks in every direction.
In the Waterloo Mine one of the fault planes exhibited a regularity seldom seen in any mine. It coursed through the light-colored, soft tufa in an easterly and westerly direction, was perfectly true, and as smooth as any hard-finished wall could be made by the most skillful artisan. The fracture was of knife-blade thinness, and its sides were coated with dark red iron oxide. It dipped to the southward at an angle of about 40°. At one time it was considered to be the hanging wall of the lode, but a miner broke through the wall to cut a hitch for a timber and it was found that the overlying rock beyond the slip was ore-bearing also. Stopes in this mine were frequently over ten sets in width, or over 60 feet. At the eastern end of the claim some extremely rich ore was mined from a belt of jasper, a metamorphosed clay shale, which by heat and pressure had become an intensely hard, fine-grained, flinty rock, yet some of this jasper contained over 1,000 ounces of silver per ton.
In West Calico, 2 miles west of the Waterloo, is the Langtry group of claims. The principal development is on the west end of the Langtry Mine. The Langtry may be called the anomaly of the camp, as it is a fissure vein pure and simple, or, more strictly speaking, two fissures.
The strike of these two fissures, which are 60 feet apart, is nearly parallel, but they will undoubtedly meet in depth. That on the south side dips northerly, while the other pitches toward the south slightly. Both stand at a high angle, and it is doubtful if they will converge inside of 250 feet from the surface. The veins are composed principally of a coarsely crystallized baryta with quartz, containing brown iron oxides, lead carbonate, ochre, manganese oxide, and chloride of silver. The average value of the ore was about 22 ounces per ton. The veins vary from a thin seam to over 10 feet in width on the north vein, having an average width of 3 or 4 feet. These veins occur in the “outside” or “mud” country, which lies along the flank of the southern slope of the Calico Mountains. The mud shales and argillaceous sandstones here lie nearly horizontal, the veins cutting them at an angle closely approximating 90°.
The low price of silver during the past two years has resulted disastrously to the mining industry in Calico District. The great Waterloo, for many years the largest producer, and employing not less than 150 men in mines and mills, was closed down, as it seemed foolhardy to exhaust the great ore bodies when the profit derived from the extraction and milling of the ores was merely nominal. For years these mines had kept the sixty-stamp Boss process mill and the fifteen-stamp pan mill at Daggett busy night and day, but in the spring of 1892 the stamps were hung up and the mines closed, awaiting better prices for silver.
The Silver King Mining Company (limited), of London, has continued to operate, dropping twenty to thirty stamps night and day, under the superintendency of William S. Edwards. The King Company owns or controls three important groups of mines in this district, viz.: the Odessa, the Oriental, and the Occidental. The Odessa made a record during the early history of the camp by the production of ores of high grade. The policy which was pursued in those “palmy days”—to gouge out the rich ore whenever it could be found, without regard to future condition of the mine—left most of the mines in very bad shape. The Odessa is now recovering under the new management, and the property is being systematically opened, and it is thought all the ore can be extracted. In this mine are stopes from which thousands of tons of ore have been mined, and there is not a stick of timber of any kind in them.
These old stopes are being cleaned out, new levels opened, and good results are expected in the future. What applies to the Odessa in this respect is true to a great extent of every other large mine in Calico. They were all worked in a hand-to-mouth sort of fashion, and although many of these mines paid handsome dividends, little of the money was ever put back in anything like permanent improvement. All seemed to share a common opinion—that the deposits were superficial, and would not go down, and as a result no one felt like laying out money in an extravagant and unwarranted manner. But the mines have gone down, and the men in charge of the mines to-day can see the result of the mistaken economy of the early operators, and see in Calico an era of recovery of low-grade ore bodies and development work which is calculated to give the mines greater apparent permanency than ever heretofore. December 1, 1891, the King mill was enlarged by the addition of ten stamps, making thirty in all. The Boss process of continuous amalgamation was also adopted.
A system of leasing portions of mining claims, called “chloriding” in Calico, was introduced in the early days, and is still in vogue. Many poor men have made moderate fortunes in the district, and in days gone by all did well. The mines are leased on a royalty of one fourth to one sixth of the ore to the claim owner, according to its value, the owner receiving more as the grade is higher. Chloriders were at work on the Loo, Little Waterman, Humbug, Bismarck, Blackfoot, and other mines, during the past year. The ore obtained in this manner is usually sacked and shipped to a custom mill, where it is crushed, the charges ranging from$9 to $12, according to the character of the ore, some (the more brittle) milling much faster than others.
The Waterloo property consists of four claims. The principal workings are in the Waterloo Mine, where large stopes have been extracted, though considerable amounts of ore still remain in sight. An idea of the extent of some of these Calico mines may be gained from the fact that the great ore body of the Waterloo is 1,100 feet in length, and is known to extend from the surface down to the 525-foot level. At the east end the ore-bearing zone is from 4 to 7 feet in width, widening downward. Going westward it increases in width until it is 60 to 70 feet wide. This mine, like those immediately about Calico, was worked for rich pockets, and, as a natural consequence, the mine was left in bad condition. Jos. D. Kerbaugh, the last Superintendent of the mine, had inaugurated a systematic method of extracting ore and recovered much lost ground. The ore is usually low grade, and this, in connection with the low price of silver, has resulted in the closing up of the mines. A narrow gauge railroad has been in use for several years to transport the ore from the Waterloo group and the King and Red Jacket Mines, owned by the same company, to their mills at Daggett, timber and supplies being brought to the mines on the return trips. The transportation of ore, I was informed, cost 12 cents per ton. The railroad is about 7 miles in length, and runs on a pretty steep grade.
In the upturned sedimentary beds which flank the Calico Hills, dipping outward toward the desert plain on all sides of the uplift, except where purely local disturbances have caused a reverse condition, are bedded deposits of calcium borate and gypsum (calcium sulphate). Five miles east of the town of Calico is the largest known deposit of calcium borate in the district. The bed, or vein, as it is called, was discovered some years since, and finally passed into the hands of the present owners, the Pacific Coast Borax Company, whose extensive works are located at Alameda, near San Francisco.
The borax mine occurs as a bedded vein in the sedimentary strata, which in Tertiary times were uplifted in the Calico range. The sediments are composed of sandstones, sandy clays, and clayey sands, comprising a succession of heavy-bedded, deep-water deposits, and shallow-water, thin-bedded shales and sands. These variations in the character of the strata are numerous, and mark the many oscillations of the region, whose rising or sinking either submerged the strata beneath the waters of a deep lake, or lifted them until the water flowed over the mud flats only in thin sheets, which, exposed to the rays of the sun, sometimes evaporated entirely. Climatic conditions doubtless also were an important factor in the history of these strata, which are upwards of 1,000 feet in thickness.
Underlying the sediments are the tufas of the Calico region, andbeneath them is found the mass of liparite which underlies this entire region. The sediments are not materially different from those in the immediate vicinity of Calico. The rocks have not suffered in the region about the borax deposit the slightest metamorphism.
The borax vein is traceable for several thousand feet, striking along the western and northern side of the largest sedimentary hill in the range, and finally passing down a cañon to the eastward, where it becomes a well-defined vein. Toward the western end the borate of lime appears to be much mixed with the sandy sediments, gypsum, and clays, giving the appearance of having been formed near the shore line of the basin in which this great mass of material has been left as a residuary deposit, due to the evaporation of the water containing the calcium borate.
To me it seems that what is now one of the most valuable deposits of mineral in the State was at one time the site of a Tertiary lake of considerable but as yet undetermined size. That although subjected to the same oscillations as the remainder of the region a basin formed, in which the waters collected, carrying with them the mineral salts derived from the rocks of the neighboring country. That finally the climatic conditions became such that the supply of water was less than the loss by absorption and evaporation, and the waters of the lake slowly diminished, it finally disappearing entirely, leaving on the floor of the lake a thick deposit of calcium borate of snowy whiteness.
After the deposition of the borax bed a general subsidence of the region occurred, the waters of the great Tertiary lake once more covering the whole country. Again the sands and finer sedimentary material—the erosion of the mountains—were carried down and found a resting place on the floor of the lake, the borax bed being finally covered with several hundred feet of this detritus. Now, as the same formation in which the borax mine is found, and even the lower members of the rocks of that age, are seen resting upon the high ridges and on some of the peaks of the Calico hills, it would seem highly improbable, to say the least, that these sediments were built up from the ruins of the Calico Mountains themselves, but their source was in more distant ranges.
Besides the regular vein-like deposit of calcium borate found at the borax mine, there are numerous small veinlets in other parts of the district in which calcium borate and gypsum are found filling cracks and cavities, probably as the result of infiltration. So common are these small fissures and beds of borax and gypsum that that portion of the sedimentary strata lying east of the town of Calico is usually spoken of as the borax formation by the miners of the district. To thoroughly investigate all the phenomena connected with these wonderful deposits and their mode of formation would require more time than was at my disposal.
As has been previously stated, remnants of the sediments are still found lying high up on the flanks of the mountains, and even far into the interior of the hills, and there is every probability that the entire region included in the Calico District, as well as the country for many miles around, was at one time buried a thousand feet beneath these stratified rocks.
With the uplift, the strata inclosing the borax mine were tilted and folded, and now the sheet of white calcium borate which once lay glistening in the sun on the bed of a desert dry lake stands like a great veintraversing the country. There are apparently two of these veins in close proximity to each other, but I believe them to be one and the same, being repeated as the result of an anticlinal fold. An ideal cross-section of the borax mine is here given (p. 347), showing the nature of the folding at that point; it is not drawn to a scale, being a sketch only.
To the southward of the mine is seen a large mass of liparite, which has been pushed up from below. I had not the time necessary to trace out the line of fracture, but I am of the opinion that it occurs on the line of the great fault shown on the map of the fault system of the region.
The borax vein is from 7 to 10 feet in thickness Where it has been exposed in the underground workings. The mineral is the variety of calcium borate called colemanite, named in honor of Wm. T. Coleman. It occurs in glassy crystals, some of them having large faces. Many handsome specimens of this mineral are on exhibition in the Mining Bureau museum. The mineral is mined in the same manner as ores of gold or silver. Inclined shafts are sunk on the vein, drifts and levels run, and the stopes carried up as in any other mine.
LONGITUDINAL SECTIONOFBORAX MINECALICO DISTRICT SAN BERNARDINO CO.
LONGITUDINAL SECTIONOFBORAX MINECALICO DISTRICT SAN BERNARDINO CO.
The material, when hoisted to the surface, is loaded in great wagons hauled by twenty animals and taken to Daggett, where it is shipped to the works in Alameda. The process of extracting the boracic acid from the rock as practiced in these works is not given to the public. It is known that the mineral is crushed and bolted like flour, after grinding with burrs, but the subsequent treatment is not known outside the works.
To the Superintendent, J. W. S. Perry, I am indebted for a sketch of the underground working of this remarkable mine, which is reproduced above.
The geological age of the Calico uplift has not been accurately determined, though there is little doubt that it occurred during the Tertiary age, probably the Oligocene.
In this county, about 16 miles in a southeasterly direction from Newberry Station, on the A. & P. R. R., and 28 miles easterly from Daggett, are the greatest deposits of iron ore on this coast. They consist of immense beds or masses of hematite and magnetite ore, containing a high percentage of iron, with traces only of sulphur and phosphorus. These mines have been known for many years, and they have had numerous owners by relocation and purchase, but nothing has yet been done with them. Iron men from Pittsburg and Cleveland and elsewhere have visited these mines and secured samples, and all reported favorably on the excellent quality of the ores, but there the matter was dropped.
Located 16 miles from the railroad, and probably 20 miles by any possible line of railway survey, as the grades are heavy, with neither fuel nor water, the problem of their reduction was so formidable that none dared face it, and for years this magnificent property has been waiting for some one with capital and a “process” to come and make the vast wealth available.
This interesting region has come quite prominently into public notice within the past two years. The district is located in a small range of mountains about 35 miles east of the Calico range. The nearest station to the mines is Lavic, on the line of the A. & P. R. R., from which point the mines are 9 miles distant by a good wagon road. Like most other desert mining regions it is destitute of timber, and water is not abundant, though obtainable in the dry lake basin 3½ miles from the mines. The district was discovered about nine years since, and numerous claims have been located. The work of development has been confined to a few of the most promising claims.
The mountain range in which the mines of this district occur is isolated from all others, although evidently a part of a chain extending in a northwest and southeast direction for many miles. This particular group of hills is about 4 miles in length by 1½ in width, and consists of rocks, which are all of plutonic origin. They are mostly quartz porphyry of the normal type, consisting of a fine-grained felsitic ground mass, with macroscopical crystals of quartz and feldspar.
Of several thin sections made for the purpose of microscopic study of these rocks, their behavior under the microscope is so similar that general description will suffice for all. The section is characterized by a micro-crystalline to micro-granular ground mass, sometimes to globulitic. The feldspars are so completely clouded as to leave little clue to theiridentity. Some still show faintly the parallel lines which are so characteristic of plagioclase, but some of these feldspars are probably orthoclase. These feldspars are plainly distinguishable in the rock mass with the unaided eye. Quartz blebs as large as small peas, with many smaller ones, occur plentifully in all of these rocks. In the section they seem to have been corroded, the outlines being nearly always rounded, though frequently showing hexagonal forms. Most of these quartz grains polarize in brilliant colors. All of the quartzes contain a great abundance of fluid inclusions, some of which show included air bubbles. Numerous very small, colorless, needle-like crystals, which occur in all the quartz, are no doubt apatite prisms. Green, dust-like hornblende as inclusions are not at all uncommon, and in one section a mass of green, fibrous material, having all the optical properties of hornblende, is seen. This inclusion is large enough to be easily distinguished with the unaided eye. There are numerous globulitic, granular, and sac-like inclusions of the ground mass in many of the quartzes, which is characteristic of the quartz porphyries generally. Besides these macroscopic crystals of quartz and feldspar are many hornblendes, some of which are of good size, a few having the typical crystal outlines. It is usually of a bright green color, strongly dichroic, and polarizes in the usual colors. Some of the hornblende is altered to chlorite. Borders of iron ore, probably magnetite, are common, frequently preserving the original outline where the hornblende has suffered great decomposition.
Dark-green basic dikes, which seem to be greatly altered diabase, occur in the district, but have no connection with any of the ore deposits as far as observed.
Numerous dikes, large and small, of a red felsitic rock, occur throughout the district, and seem to bear an important relation to some of the ore deposits. All of the rock is much decomposed, and its identification is not an easy matter. It appears under the microscope to be a finely porphyritic rock, having a somewhat fluidal structure, as shown in the arrangement of the numerous small, lath-like crystals of feldspar. Small blebs of quartz occur quite abundantly. In a general way the rock resembles some rhyolites.
On the northern flank of the range immense masses of red and brown tufa occur, besides great flows of black basaltic lava. These rocks form a terrace-like ridge that extends for several miles along the base of the mountains. Two large cinder cones, one on the northeast end of the range, the other about 4 miles distant in the desert valley to the northward, form prominent landmarks.
The basalt is coarse to fine grained, usually black or dark gray, and is often scoriaceous. It contains plagioclase, augite, and olivine, and abundant magnetite in a micro-crystalline or granular base. Near the foot of the range the basalt has overflowed the beds of tufa, which latter, it is said, contains from a trace to as high as four ounces of silver per ton. As far as I have any knowledge of it, no prospecting has been done in these tufa beds, but the fact that silver exists there at all would lead one to believe that under proper conditions ore bodies of great value may occur.
At the base of the mountains, at an altitude of 1,800 feet, is a dry lake, which drains a large area of country. In this basin water has been obtained by sinking a well 80 feet in depth. Though the well is locatednear the edge of the basin, there is little doubt that sufficient water can be obtained in this basin for milling purposes.
The principal vein in the district lies along the north side of the main range, and is known as
This great vein, the outcrop of which may be seen for 20 miles, is a “fissure” in every sense of the word, though not a simple one, for it has numerous divergent branches of considerable size. The main fissure, however, is strong and constant, and outcrops boldly for nearly 8,000 feet. It varies in width from 4 to 18 feet. It is everywhere well defined and often shows a banded structure.
The great fissure strikes north 70° west, and dips 65° to 70° to the south. It occurs in the quartz porphyry, which at contact with the vein is usually much decomposed and often shattered and crushed, probably owing partly to the intrusion of a large dike of the red felsitic rock, a tongue of which has cut across the vein about 3,500 feet from its west end. This dike follows the vein for some distance on the hanging wall side coming from the east, gradually nearing the vein until it finally reaches the fissure, cutting the vein in two. Farther westward it again appears on the hanging wall side, showing itself at intervals to the extreme western end of the vein, which comes to an abrupt termination. This felsitic dike is but one of a number that occur in the immediate vicinity.