Three miles from Hinkley Station, on the Atlantic and Pacific Railroad, between Barstow and Mojave, is located the Kent Mine, a vein covered by two claims. A shaft 80 feet deep and some superficial development have exposed the ore, which varies from 3 to 10 feet in width. The gangue is a rather fine-grained, granular quartz, containing galena and lead carbonate. Assays in gold and silver are obtainable anywhere in the vein. The highest grade carries lead 70 per cent, gold $25, silver 24 ounces. Some of the ore assaying low in lead contains gold and silver in paying quantities.
The property is in a prospective stage only, but is promising. Water can be obtained near the mine, and fuel is but 8 miles distant. The owner bonded the property in May, 1892, and it is at this writing being developed by the prospective purchasers. The ore is of such character that by sorting a milling ore may be obtained, the high-grade lead ore making a very good smelting material.
THE BLACK HAWK DISTRICT.
Three years ago the Black Hawk District, 40 miles east of Victor, on the north side of the San Bernardino range, attracted considerable attention through the extensive operations of an English syndicate at those mines. Development was in progress at that time, and it was planned to build a sixty-stamp mill. The quantity of gold rock, however, proved to be smaller than had been anticipated, and a small experimental mill was built; but from a short time after the completion of this mill to date all operations have been suspended, and the probability of the resumption of work is not bright.
The gold occurred in a reddish oxide of iron in bunches and stringers scattered through a crushed zone of limestone, lying along the flank of the mountains. A party, who for a time was in charge of the property, informed the writer that he had worked the rock without sorting, had endeavored to sort it, and had tried screening it, but that notwithstanding every precaution was taken, he had concluded that it could not be made to pay. The gold-bearing rock was quite rich, but it occurred in too small quantity to make it profitable.
SILVER REEF DISTRICT.
Four miles northeast of the Black Hawk Mines, lying down on the desert, is a formation of limestone and quartzite, resting on a massive crystalline rock, containing quartz, feldspar, biotite-mica, and hornblende. This reef extends from the mouth of Texas Cañon out upon the plain, sloping downward at an angle of approximately 5° for a distance of 4 miles, where it terminates in a bluff 40 to 100 feet in height. Along the entire eastern edge of this deposit it drops off abruptly as though sharply eroded. At the northern end the reef is faced by a low range of hills composed of the above-mentioned hornblende rock. From this point it swings west and with irregular outline extends for 5 or 6 miles toward Rabbit Springs. The entire area, fully 25 square miles, is cut by gulches varying from 20 to 150 feet or more in depth, that have been eroded through the strata and down into the underlying crystalline rocks. These cañons seem to have resulted from natural drainage, being started by slight depressions in the rolling plateau of limestone. On the extreme northern edge at one point, hills of considerable size have been formed by the folding and tilting of the strata. The limestone has been subjected to violent compression, as the whole area is faulted and broken into millions of fragments.
I have examined not less than twenty mining claims on the reef and traveled over the greater part of its area, and am sure I never saw a single piece of limestone that would weigh 300 pounds, most of the pieces measuring under 6 or 8 inches. Considerable masses along certain zones have been granulated, and even pulverized. This fractured rock has all since been loosely cemented by the infiltration of carbonate of lime into the seams. Geologists who have examined this peculiar deposit do not agree entirely upon its mode of formation. Some believe it to be the result of chemical precipitation of carbonate of lime from calcareous springs, similar to the Formation Springs in the Yellowstone Park. There are many things about Silver Reef which would at once suggest the probability of this mode of deposit, but I am very doubtful that such a theory will stand a thorough investigation.
It was asserted that at one time a shaft sunk in the reef passed through the lime deposit and into the “wash” of the desert beneath. On investigation I found that the lime had indeed been cut through, but the underlying rock proved to be crystalline hornblende rock in place, though somewhat decomposed. At any rate it was not desert “wash.” Over considerable areas the lime is underlaid by a stratum of quartzite of variable thickness, less than a foot in some places, and again in others 10 or 12 feet. Over certain limited areas quartzite is wanting altogether. The lime is mostly crystalline, varying in color. A small portion is as white as snow, the greater part is gray or bluish, and some of it black.