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Inyo County

  • Inyo County Mines and Mineral Resources (circa 1915-1916) - Excerpts from Report XV of the State Mineralogist, Mines and Mineral Resources of Portions of California, Chapters of State Mineralogist's Report Biennial Period 1915-1916, Part I. Alpine County, Inyo County, Mono County, California State Mining Bureau, 1919, pp. 28-134. (Used with permission, California Department of Conservation, California Geological Survey.)


    “The field work for this report was carried on during the months of March and April of the year 1916. The expedition made use of a light automobile, which proved a very rapid and efficient instrument for covering the great wastes of desert gravel and sand, as well as the steep mountain roads."

    Location and Description (of Inyo County)

    “Inyo County lies along the eastern border of California and is bounded on the north and south by Mono and San Bernardino counties respectively. The western boundary extends to the Sierran divide. The county has an area of 10,224 square miles, being the second largest county in California. Independence is the county seat, while Bishop, with about 2000 inhabitants at present (circa 1915-1916), is the center of the population. Since the great increase in mining activity during the last year the population has increased considerably, so that at present there is probably an average of one inhabitant to each square mile of territory. Within the borders of the county are both the highest point and the lowest point in the United States. Mount Whitney has an elevation of 14,501 feet, while the lowest point in Death Valley, at Salt Flat, is 280 feet below sea level."

    Hints for Travelers in Machines (in Inyo County circa 1916)

    "Since so much prospecting is now being done in automobiles (circa 1915-1916), it is deemed fitting to include a few suggestions which may be of help in desert regions.

    "The best months for traveling in eastern Inyo County are from March to June, inclusive. During the summer months the heat is intense, water scarce and the sands dry and loose. The winter months are very cold and storms sudden and severe, but the sands are often moist, or west, and hard. When traveling, even in a light machine, one should have a helper, and carry extra water, gasoline, oil, castings and inner tubes. For the tool kit, a small shovel and set of differential pulleys, such as the 'Pull-U-Out,' is often a 'life-saver' when attached to a 'deadman' or plant 2"x6"x6' long, buried in a trench 2 feet deep. For deep sand or gravel, soft or deflated tires often enable the machine to pull through, or twigs of brush laid across the sand to corduroy the road are often essential. When the machine is stuck in the sand, it may be cranked out, if the spark plugs are removed to relieve the cylinder compression, and the low gear used...."

    Railroads (in Inyo County)

    "As yet Inyo County is only partially served by railroads (circa 1915-1916). The Southern Pacific Company has a broad-gauge line from Mojave to Owenyo, where it connects with their narrow-gauge line from Keeler to Tonopah Junction, Nevada...."

    Economic Geology (in Inyo County)

    "During the year 1915, the following minerals were being produced in Inyo County: antimony, borax, copper, dolomite, gold, gypsum, lead, marble, pumice, silver, zinc, salt, soda, talc, and tungsten. Deposits of iron, molybdenum, niter, potash, quicksilver, and silica also occur but have not as yet been developed...."

    Economic Conditions

    Transportation (in Inyo County)

    Mines located in the region of Owens and Amargosa valleys are easily accessible from the Southern Pacific and Tonopah and Tidewater railroads. Roads and trails make the interior of the county accessible, but hauling is difficult because of steep grades and deep sands."

    Power (in Inyo County)

    "Electric power, generated in the Sierras west of Bishop, is available in the northern and western parts of the county. The eastern, southeastern and central portions of the county are dependent on internal combustion engines, and these are often prohibitive because of high freight rates...."

    The table* after page 56 states that the totals for stone products were: (1) Soapstone: 3,953 tons, $25,710, and (2) Marble: 78,400 cubic feet, $219,300. The combined Total for all minerals for the 1880-1915 period was $23,039,146. Soapstone statistics began in 1912, and statistics for marble began in 1894.

    (* Inyo County - Table of Mineral Production (by year) 1880-1915. This table will not be presented in this document.)

    Marble (in Inyo County)

    "The marble deposits of Inyo County occur on the southwestern flank of the Inyo Range and extend for about 6 miles northeastward from Swansea station. The mountain range here consists of folded and faulted sediments of Carboniferous and Triassic age, altered by regional metamorphism to slates, quartzites and marbles, intruded by occasional basic dikes. The marble outcropping along the base of this range shows a thickness of at least 500 feet. The beds are tilted at a high angle, dipping northwestward into the mountain. They are fractured and faulted, so that the marble is considerably shattered at the surface. The marble is dolomitic, generally fine-grained, hard, and very resistant to weathering, as indicated by the sharp corners and fresh surfaces of the talus blocks. Three varieties are found, a pure white marble, a beautiful yellow marble and a variegated marble of white ground mass, penetrated by dendritic markings of manganese. The white marble is the one upon which most of the quarrying has been done. This takes a beautiful polish, as is exemplified by its use in the Mills Building, of San Francisco.

    "These deposits were first quarried in 1888 by the original Inyo Marble Company, of San Francisco, of which M. J. McDonald was president. The quarries lay idle for a number of years due to the shattered condition of the marble and the expense in obtaining large blocks. Assessment work was not kept up and the claims were relocated by the present owners, now known also as the Inyo Marble Company."

  • Inyo County Mineral Industry (circa 1919) - Excerpt from California Mineral Production for 1919, Bulletin No. 88, by Walter W. Bradley, California State Mining Bureau, 1920, pp. 148-149.

    Area: 10,019 square miles.
    Population: 7,031 (1920 census).
    Location: Lies on eastern border of state, north of San Bernardino County.

    "Inyo, the second largest county in the state, and containing less than one inhabitant per square mile, is extremely interesting from a mineralogical point of view. It is noted because of the fact that within its borders are located both the highest point, Mount Whitney (elevation 14,502 feet), and the lowest point, Death Valley (elevation 290 feet below sea level), in the United States. In the higher mountainous sections are found many vein-forming minerals, and in the lake beds of Death Valley saline deposits exist.

    "Inyo's mineral production during the year 1919 reached a value of $2,674,835, standing twelfth among the counties of the state in this respect. The 1918 value was $5,177,676, the decrease being due mainly to lead, silver and tungsten. Its mineral resources include antimony, asbestos, barytes, borax, copper, gems, gold, gypsum, lead, marble, molybdenum, mineral water, nitre, pumice, quicksilver, salt, silver, soda, sulphur, talc, tungsten, and zinc.

    "Commercial production for 1919 was as follows:"

    (Headings for the information below are: Substance, Amount, and Value.)

    Copper, 169,713 lbs., $31,567
    Gold, ---, $90,000 (estimated)
    Lead, 3,643,485 lbs., $193,105
    Limestone, 2,360 tons, $12,000
    Silver, ---, $156,000 (estimated)
    Stone, miscellaneous, ---, $7,850
    Zinc, 1,192,353 lbs., $87,042
    Other minerals,* ---, $2,097,271
    (Total value) $2,674,835

    (* Includes borax, dolomite, marble, pumice, salt, soda, talc, and tungsten.)

    Inyo County, 1916 Map, from California Mineral Production for 1919 (with County Maps), Bulletin No. 88, by Walter W. Bradley, California State Mining Bureau, San Francisco: California State Printing Office, 1920, pp. 193. Inyo County , 1916 Map, from California Mineral Production for 1919
  • Inyo County Limestone Industry and Deposits (through 1947) - Excerpt from “Limestone in California,” by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. (Used with permission, California Department of Conservation, California Geological Survey.)

    "Limestone and dolomite occur abundantly in Inyo County, but so far their commercial utilization has been limited. One area is immediately east of Shoshone, in the southeast corner of the county. Although the sections here indicate thousands of feet in thickness of limestone and dolomite (Hazzard, J. C. 37a),* there is no production of either from the district. This area, which is small in comparison with others further north and west in the county, is about 30 miles long. An area extending over 50 miles northward from the vicinity of the Inyo Marble Company deposit near Swansea at the north end of Owens Lake, contains large quantities of limestone and dolomite ranging in age from Cambrian through Silurian, Devonian, and Carboniferous, into the Triassic. This region ranges in elevation from 4000 to over 10,000 feet and is served by a narrow-gauge railroad running from Keeler northward to Laws along the east side of Owens Valley within a few miles by road from much of this limestone. At Owenyo, 10 miles north of Owens Lake, this railroad connects with the Southern Pacific broad-gauge railroad running south to Mohave. Such shipments of limestone and dolomite as have been recorded during the past 20 years have come from Zurich and Cartago in this region. However, the limestone here has been of more interest commercially as the site of lead-silver ores, for example, occur in Devonian limestone which has been intruded by monzonite porphyry, diabase, and quartz diorite porphyry, according to W. B. Tucker and R. J. Sampson (38, p. 432).**

    (*John C. Hazzard, "Paleozoic Section in the Nopah and Resting Springs Mountains, Inyo County, California," California Division of Mines Report 33, pp. 289-339, 1937.)

    (**W. Burling Tucker and R. J. Sampson, Los Angles Field Division, "Mineral Resources of Inyo County," California Division of Mines Report 34, pp. 368-500, 1938.)

    "Other extensive areas where limestone is plentiful and is important as a wall rock for lead-silver ores include the Darwin district, where Pennsylvanian limestone occurs; the Panamint district, where different ages of Paleozoic limestone and dolomite marble of varying degrees of purity are found, and several other mountain ranges. Only the first two districts are near enough to railroads to be considered now as possible commercial sources of limestone and dolomite.

    "The latest published geologic work on the region is that of Richard G. Hopper (47). His section was taken across the south half of Inyo County. The article summarizes previous information on the limestones and dolomites and adds new details all tending to emphasize the tremendous volume of such rocks in the region."

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