Part 12

A few miles to the northwest from Julian is located the Mesa Grande District, where lenses of a yellowish pellucid quartz of semi-granular texture have been developed somewhat. All of this quartz contains gold, and some of it is quite rich; but nothing of consequence has been done of late, further than to organize a stock company.

ESCONDIDO MINES.

Near the flourishing little town of Escondido are some old Mexican mines, which have been acquired by a San Diego company. The veins are gold-bearing, the quartz having formerly been worked in arrastras with evidently good results, as the surface workings are quite extensive. Within the past two years, however, little has been done on the property.

PINE VALLEY.

The Pine Valley Mines lie 6 miles from the Stonewall and San Diego Stage road, the nearest station being Descanso. Two mills, one of five and one of two stamps, crush the rock taken from the veins in the vicinity. This quartz, it was claimed, would mill over $50 per ton. The veins occur in a formation similar to that about Julian and Banner.

REPORTED TIN DISCOVERIES.

Frequently there have been rumors of the discovery of tin stone in San Diego County, but up to this time no such ores are known to exist outside of the property known as the Temescal Mines, which are located on the line of San Bernardino and San Diego Counties. However, in the large crystalline area which extends over a considerable portion of San Diego County, it would not be strange to find tin stone under conditions similar to those which obtain in the Harney Peak region in the Black Hills of Dakota. There the cassiterite is found in good-sized crystals and finely disseminated grains in a matrix of coarse-grained granite, which has been thrust up through the schists in the form of intrusive dikes of greater or less size. It usually is associated with tourmaline, wolfram, and other black minerals, making it difficult to distinguish it without making a test of some sort. The search for tin in San Diego County has been confined to looking for a black rock similar to that found in the Cajalco Mine.

DULZURA DISTRICT.

The Dulzura Mining District is 30 miles east and a little south of the city of San Diego, in a range of rather rugged mountains. Metamorphic rocks occur frequently, but masses of igneous rock have been intruded and constitute large hills throughout the district. Among these rocks are a light, greenish-gray feldspar porphyry, a dark-green, fine-grained diorite, a black aphanitic diorite, sometimes porphyritic, and a light cream-colored or greenish-white felsitic rock. In the immediate vicinity of Dulzura the latter rock occurs in the form of immense dikes striking northwest and southeast, crossing Cottonwood Creek to the south into Mexico. In one of these great dikes, which is several hundred feet in width, the mines of the district are found. They are principally chambered veins occurring on the line of a fault plane which has fractured the felsite, the hanging wall side of the slip going down, the movement causing the rock to become crushed and broken. Percolating waters have carried into the crushed mass mineral solutions, which have deposited the ores, chiefly iron sulphurets, where the most favorable conditions were found along the line of this fault plane. The subsequent oxidizing of the masses of ore thus formed has stained the rock a bright or dark red and sometimes yellow.

The rock contains gold ranging from a trace to $20 or over per ton. It was said the average was about $8. The oxidation of the ore bodies does not extend to any very great depth, the result being the occurrence of sulphuretted ores comparatively near the surface, though it was claimed by the mine owners that the sulphurets contained sufficient gold to make concentration and treatment by chlorination profitable. The mines are quite interesting from a geological point of view, and may, in time, prove equally so from a financial standpoint. No machinery had been built at the time of my visit. The felsite throughout the district, whenever observed, contained a considerable amount of pyrite, the surface rock nearly always presenting a highly mineralized appearance.

JAMUL CEMENT ROCKS.

The Jamul Portland Cement Mine and works are located on the Jamul rancho, 22 miles east of the city of San Diego. The company began the construction of expensive works in the spring of 1890, which were not completed until June, 1891, at a cost of $50,000. Seven kilns were constructed, together with large buildings. The capacity of the works is about 150 barrels a day. When in operation over forty men are employed at the mine and works.

The transportation problem proved a more serious one than had been anticipated, it costing more to haul cement from Jamul to San Diego than it costs to bring English Portland cement to California by vessel. The cement made by this company has been quite extensively used throughout Southern California.

ASBESTOS.

The John D. Hoff Asbestos Company, of San Diego, is operating an asbestos mine in the San Jacinto Mountains, from the product of which a variety of fire-proof material is made, including roof paints, roofing, boiler and steam-pipe covering, fire-clay goods, etc. This is the only asbestos concern in the southern part of the State, and the business seems to be on the increase. The works are located near Pacific Beach, 7 miles from San Diego. Asbestos is also found near Palm Springs, in the San Jacinto Mountains, and several miles east of Indio.

PINACATE DISTRICT.

Near the line of San Bernardino and San Diego Counties, about 5 to 8 miles west from the town of Perris, are the mines of the Pinacate District, all being veins of quartz-bearing gold. In past years this district has produced a large amount of bullion, the quartz being worked in arrastras, the beds of over a hundred of which still may be seen scattered about.

There are numerous springs of small size in the district, but timber is very scarce. The formation is syenite and granite principally; occasionally schistose and gneissoid rocks and quartzites being observed. The entire region is metamorphic, excepting a few dikes of granite (pegmatite) and quartz porphyry. Diorite is found near the Good Hope Mine. The region is one easily accessible, and but 4 to 8 miles from a railroad.

STEELE’S MINE.

To the northwest of the Good Hope Mine is the Victor Mine, formerly “La Plomo.” This mine is now better known as the Steele Mine. The vein is a foot or more in width, consisting of a highly crystalline quartz, in which is disseminated a small amount of iron and lead sulphuret and lead carbonate. The rock is quite rich in gold, some of it showing gold without the aid of a lens.

A tunnel 900 feet in length had been run to develop the vein, on which an inclined shaft had been sunk to a depth of 200 feet. Besides this work there were numerous other superficial workings, in which quartz of good grade was exposed. The vein occurs in a region of metamorphic rocks, the foot wall containing much quartz and biotite mica. The hanging wall is dark gray color, and quite fine-grained in texture. Hornblende crystals are plentiful throughout the rock. Other rocks in the vicinity are mica schist, chloritic rocks, quartzite, and other more massive crystalline rocks. Granitic dikes (pegmatite) cut the formation on all sides, none of them being very large. These dikes are characterized by their exceptionally coarse crystallization. Good-sized tourmalines, of jet black color, are numerous in the granite.

THE ROSALIA.

About a mile northwest from the Victor is the Old Rosalia, now the Santa Rosa, which is opened along the surface for over 1,000 feet by cuts and shafts. The upper portion of the vein was worked out years ago, but new capital has been interested and a new shaft was being sunk at the north end of the property.

The inclosing rock on either side of the vein is very soft and much decomposed, requiring more timber than had ever been used by the former operators. The mine has produced a large amount of gold, which was extracted by working the quartz in arrastras, and in later years in a mill, which still stands on the mine. At the north end it was understood that the shoot of pay rock was still intact, and it is to recover this that the new work was being inaugurated. The balance of the shoot to the south has all been worked out down to the water-line.

THE SANTA FE.

Not over half a mile from the Rosalia is the old Santa Fe Mine, which in days gone by was a producer of gold, but its workings had long been abandoned.

THE SHAY MINE

Is also in the Pinacate District, 6 miles west of Perris. Several holes have been sunk on the vein, but the entire lower portion of the mine was flooded and could not be examined. The quartz is a bluish, ribbon-like rock, and carries considerable gold. The owner from lack of means is unable to work the mine.

There are numerous other mines or veins in the district, many of which have been worked in former years by Mexicans, who coyoted about, working the narrow seams and crushing the quartz in arrastras. These veins are now abandoned, and no one seems to have sufficient faith in their value to undertake anything like systematic development. The veins mostly lie quite flat in granite or syenitic rocks. They are usually from 4 to 16 inches in thickness and extend some distance. Roads are constructed to nearly all of them. It seems like a region promising good returns on small investments. One ten-stamp custom mill could crush the rock for all the veins of this district. I was informed that much of the rock returned from $60 to over $100 per ton.

THE MENIFEE MINE

Is located south of Perris about 8 miles. The vein contains gold-bearing quartz. The foot wall is a chloritic schist, back of which lies a syenitic rock. The hanging wall is syenitic granite, the hornblende having changed partly to chlorite. The vein is from 1 foot to 30 inches in width, and strikes northeast and southwest, dipping west 80° to a depth of 40 feet, where it flattens out to 65°. The quartz mills about $15 per ton, and contains but a small percentage of sulphurets. There are four shafts on the vein, varying from 35 to 60 feet in depth, the main shaft having a double compartment, being 5 by 11 feet. They have a five-stamp mill.

THE WALKER CLAIM.

Within a mile of the Menifee, in a northeasterly direction, a new discovery was made in the spring of 1892 of a quartz vein which occurs on a low mound at the base of low, rolling hills. The vein was small, 4 inches to a foot, quite heavily mineralized, but much broken. Two distinct faults occurred in a length of 90 feet, where the vein had been exposed. Two shafts were down 30 feet each, and water was coming in. The finding of specimen rock had created quite an excitement in the vicinity, and visitors were numerous. The rock, I judged, would pan out about $40, but too small an amount of work had been accomplished to make any estimate of the value of the vein possible.

CARGO MUCHACHO MINE.

In the Cargo Muchacho District, 30 miles in a northerly direction from Yuma, the Cargo Muchacho Mine has again been in operation within the past two years. The owners moved the mill from the Paymaster Mine to a site near the former property, laid a double pipe-line 14 miles from the Colorado River, and have supplied the camp with water in this manner. The latest reports from the district are to the effect that the mill and mine are being operated steadily, with satisfactory results.

THE PASADENA MINE.

About one mile north from the Cargo Muchacho is a vein on which several locations have been made. Of these the Pasadena and Peterson claims are most prominent. The vein covered by the locations has been quite extensively opened, and possesses many of the features of the Cargo Muchacho.

The quartz was sent, at no small expense, to a mill at El Rio, on the Colorado River. The expense of mining was seldom less than $2 a ton; transportation to the S. P. R. R. at Ogilby Station, 6 miles, $2 50; transportation by rail to El Rio, 14 miles, 50 cents a ton, making at least $5 a ton. The mill was leased at $10 per day, to which the expense of milling was added, making fully $4 a ton more, or about $9 in all. It was claimed that the rock averaged $16. Doubtless some of it did, but it is probable the expense really exceeded the figures given.

With water pumped into the district it is quite possible that this mine, and the Peterson claim adjoining, may be operated at a profit, which under former conditions was impossible. There are many other gold-bearing veins in the region, but none of them are extensively developed.

EAGLE MOUNTAIN.

Unusual activity has characterized operations about that portion of the Colorado Desert, about 90 miles east of the San Bernardino Mountain, near the line between San Diego and San Bernardino Counties. The Eagle Mountain District is one of these localities. The discovery of rich placers in the dry gulches of that section resulted in a more thorough investigation of its mineral resources and in the finding of some very rich gold-bearing quartz. Considerable work has been done on these claims and the prospects are considered very flattering.

A cemented basin has been constructed to catch the rain water that falls during the winter season, with which it is intended to work the placer mines. The discoverers of these mines, it is said, took enough gold from the gulches, in making the basin referred to, with a dry washer, to pay for making and cementing the basin.

COTTONWOOD SPRINGS.

Twenty-six miles in a northeast direction from Walters Station, on the line of the S. P. R. R., at an altitude of 3,004 feet, is Cottonwood Springs. A range of mountains, in which occur granitic and metamorphic rocks and eruptive dikes, strikes east and west across the desert, and in these occur several springs. There is but one mine in the immediate vicinity of the springs, and this is known as

THE COYOTE MINE,

Where a reading of the aneroid indicated 3,300 feet. The formation in which the Coyote vein has formed is micaceous and hornblende schist and gneissoid rock; hornblende granite and dikes of diorite also occur in the vicinity of the vein. The Coyote Mine is a quartz vein from 2 to 4 feet in width. The rock is iron stained and occasionally shows free gold. The vein is developed by two shafts, one about 20 and the other nearly 80 feet in depth, and strikes 5° north of east, having a dip of 46° to the south. The vein appeared to cut the formation at a small angle. A fault, which has occurred within the vein, had evidently puzzled the owners, as at the bottom of the 20-foot shaft they had developed 8 feet of what looked like solid quartz. The vein is really but 4 feet in width at that point, but the fault cutting downward at an angle of 45° and crossing the strike of the vein at an angle of 27° had allowed the hanging wall side of the fault to slip downward, thus doubling the width of quartz, which was much shattered. The miners had quit work, leaving what they considered well enough alone. In the deeper shaft the fault had carried the hanging wall down and to the east a few feet, and the vein was lost altogether. A short drift had been run into the hanging wall, but not finding the vein, work had been suspended. The vein lies on the foot wall side and not more than 4 or 5 feet from the line of the slip.

SALTON LAKE.

By E. B. Preston, E.M., Assistant in the Field.

The Coahuila Valley, in which Salton Lake is situated, is 90 miles long and from 10 to 30 wide. It separates the San Bernardino range of mountains from the San Jacinto, and forms a part of the great Colorado Desert in San Diego County. In its deepest portions it is 275 feet below the level of the sea; the area of the depressed region is over 1,600 square miles. In its northern portion the valley consists of sandhills and dunes, the former caused by the accumulation of the sand around the scrub and bushes growing in the desert. The southern portion is bare clay. On the borders of the desert palm trees of the fan palm variety occur in a few scattered clusters. The Southern Pacific Railroad passes through the valley on its way to Yuma.

In that part of the depression adjacent to the railroad station of Salton is a salt marsh, where the New Liverpool Salt Company’s works are located, and where a fine quality of table salt is produced, containing, according to an analysis made by Thomas Price, of San Francisco:

Chloride of sodium 94.68 per cent. Calcium sulphate .77 per cent. Magnesium sulphate 3.12 per cent. Sodium sulphate .68 per cent. Water .75 per cent. 100.00 per cent.

The brine from which the salt is obtained shows a density of 27° Baumé.

The company’s works are situated about 3,000 feet west of the railroad track, and consist of the salt mill and a large storehouse, connected by track with the main line. This branch line extends into the marsh a distance of over 10,000 feet. Beyond the end of the track a borehole was sunk by the company, with the expectation of obtaining water, to a depth of 300 feet, when the work was interrupted.

The strata passed through during the sinking throw some light on the past condition of the desert depression, as well as furnishing some points that may have a bearing on the flooding of this section.

The top covering consists of 6 inches of black mud, resting on a crust of chlorides of sodium and magnesium, 7 inches in thickness. The drill on passing through this crust dropped through 22 feet of a black ooze, containing over 50 per cent of water. Tests of the ooze made at the State Mining Bureau laboratory showed it to consist largely of chlorides and carbonates of sodium and magnesium, the soda salts predominating, besides fine sand, iron oxide, and clay, and a small amount of organic matter. The ooze was resting on a hard clay bottom, through which the drill passed for the entire remaining distance, only varied by two or three streaks of cement. From the shore line of the marsh toward the adjacent mountain ranges, the soil consists of a fine sand, containing clay and a notable quantity of mica, and is strewn with well-preserved shells of _Planorbis ammon_, Gould, _Physa humerosa_, Gould, and _Amnicola protea_, Gould.

In a few spots near the northwest end of the marsh the accumulated cases of a species of Caddice worm are found. Northeast of the marsh the surface slopes gradually upward to where the remains of an ancient sea beach are to be seen, stretching to the south and east to where the Colorado River cuts through on its way to the Gulf of California.

Behind the beach extends a mesa to the foot of the San Bernardino range. Across this mesa are evidences of heavy floods coming down the cañons of the back range, carrying large quantities of debris with them, mostly bowlders of mica schists and granitoid rocks, with some quartz intermixed. On the west side of the marsh the surface has but little elevation until the granitic bluffs of the San Jacinto range are reached. These bluffs are coated for a distance of about 25 feet above the plain with a sponge-shaped incrustation from 2 to 3 inches thick, consisting largely of carbonate of lime, chloride of sodium, sand, clay, and oxide of iron; under the glass some of the pores are seen to contain minute shells of the same varieties as found on the sand of the plain. Where arroyos have been cut through the sands of the plains to the depth of several feet, the exposed sections show a stratified arrangement of the sand, having between the layers a thin division of the same varieties of shells as found on the surface, the whole resting on a firm clay bottom. From the position and regularity, as well as the quantity of these shells, on top of the different strata of sand, while but few are seen scattered through the sand layers, a periodicity of the conditions favorable to their existence and growth, as well as a comparatively sudden cessation of the same, must be inferred. These conditions mean an occasional flooding of the depression for a period of time, during which a shallow body of water was maintained, which evaporated as soon as the water supply was shut off. In what manner this can occur will be shown later on. The plain supports a scant growth of desert shrubs, with some mesquite bushes in the vicinity of the few springs that are found scattered over the desert, most of which are saline. The presence of the extensive line of sea beach proves that at some time the gulf has extended much farther inland than at present, covering the whole of this depression. The Colorado River, in its course south to the ocean, built up a flood plain on a higher level that finally shut off the western part from a direct communication with the sea, and evaporation, with a gradual uplifting of this whole section, finally laid it bare, although leaving a great part of it still below the present sea-level. Under these conditions, whenever more water comes down the river than its banks can contain, the silt-formed shores give way to the increased pressure and permit the excess of water to flow to, and gather in, what is termed the river swamp at the back of the flood plain, from whence it either re-enters the river lower down in its course, or finds its way into the depression.

The Salton Marsh at present acts as the catchment basin for the waters draining from the east side of the San Jacinto range, Carizoo Creek, and a part of the San Bernardino Mountain range, and in times of extreme high waters as a reservoir for the excess in the Colorado River. In the month of June, 1891, a steady flow of water entered the depression from the southeast and continued to the northwest uninterruptedly until an area 30 miles long and averaging 10 miles in width was covered to a depth of 6 feet, measured at the end of the Salton Salt Works branch track. When first examined the water showed a density of 7° Baumé, which gradually increased to 25° Baumé. The mother liquor used in making salt at the New Liverpool works usually shows a density of 27° Baumé. This salt water gave rise to the idea that the waters from the gulf had made an inroad through some underground channel, and to prove the source and possible permanency of these waters several investigating parties were sent out. No such previous incursion had been witnessed by the settlers, but inquiry proved that a similar lake existed here in 1849. Finally one of the parties showed that the Colorado River was the source, and then the question was brought to the attention of the State Mining Bureau to investigate as to the probability of the permanency of the lake and its probable effect on the climate of the surrounding country.

The Colorado in its great length accumulates a large amount of sediment, from 0.1 to 0.4 per cent per gallon, and after this has been deposited the water on evaporation is found to contain 0.14 grammes solid residue, consisting largely of sulphate of soda and chloride of sodium. With the sediment the river is all the time building up its flood plain, and it may not be out of place to recall the general laws that govern the actions of streams while depositing the solid matter they carry in suspension.

Currents bearing sediments deposit a large percentage as soon as their velocity is checked in the least, but pick up deposited sediments again as soon as the current is increased. Thus a variable current is depositing at one point while eroding deposits at other points.