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Merced County


  • Merced County Mines and Mineral Resources (circa 1913-1914) - Excerpt from Report XIV of the State Mineralogist - Mines and Mineral Resources of Portions of California, Chapters of State Mineralogist's Report - Biennial Period 1913-1914, Part IV. "The Counties of Fresno, Kern, Kings, Madera, Mariposa, Merced, San Joaquin, Stanislaus," by F. L. Lowell, Field Assistant (field work in September, 1914), San Francisco, California, July, 1915, California State Mining Bureau, San Francisco, California, 1916, pp. 173-370.

    "Merced is, strictly speaking, an agricultural county. Most of its 1,276,800 acres of land is under cultivation and the question of water has long been settled by the introduction of a system of irrigating ditches which is augmented by numerous flowing wells.

    "There is very little mineral in the county and only one gold mining company operating (circa 1914). The mineral indications are found in the Coast Range mountains in the southwestern part of the county adjoining Santa Clara County and in the northeastern part adjoining Mariposa County."

  • Merced County Slate Industry (through 1914) - Excerpt from Slate in the United States, Bulletin 586, by T. Nelson Dale and Others, United States Geological Survey, Washington: Government Printing Office, 1914, pp. 70.)

    "A slate deposit was discovered in 1912 about 11 miles east of Planada, probably the Mariposa slate and of Jurassic age.* It is reported as 1,500 feet in width at the surface, 3 miles in length, and 300 feet in vertical thickness. The California Slate Co., of Planada, has commenced to develop the property. A specimen of the slate examined by the writer yields these results.

    (* Page 70 footnote 1: See Turner, H. W., and Ransome, F. L., United States Geological Survey Geol. Atlas, Sonora folio (No. 41), p. 2, 1897.)

    "This slate is of dark bluish-gray color, with a somewhat lustrous, very finely granular surface with minute striations along the grain. Its fissility is good. It is very sonorous, indicating a high degree of metamorphism, does not effervesce with cold dilute hydrochloric acid nor show any carbonate in thin section, indicating durability of color. It is graphitic and contains many bronze-colored magnetic particles. Magnetite is not certainly present.

    "Under the microscope it shows a matrix of muscovite (sericite) very even in the grain direction with brilliant aggregate polarization, also conspicuous lenses with a nucleus of black mica (biotite). The biotite scales lie mostly parallel to the grain direction and the lenses, partly biotite and partly quartz, are elongated in the grain direction, but the biotite nucleus is crossed by parallel bands of dark inclusions that lie in the cleavage direction. It also contains many bronze-colored metallic particles and minute lenses of a highly magnetic mineral, presumably pyrrhotite (magnetic pyrites). The chief constituents of this slate, named in descending order of abundance, appear to be muscovite, quartz, biotite, kaolin, graphite, and pyrrhotite. Magnetite and rutile are not certainly present.

    "This is a mica slate of sedimentary origin, free from carbonate, with good cleavage. It should discolor but little if at all, but its content of magnetic particles makes it unsuitable for electrical uses."

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

    Area: 1,995 square miles.
    Population: 24,579 (1920 census).
    Location: About the geographical center of the state.

    "Merced County as a whole lies in the San Joaquin Valley, and it figures as one of the lesser mineral-producing counties of the state. The 1919 mineral output was valued at $40,350. The decrease from the value of $74,849 in 1918 was due to gold. Gold, platinum, and silver, obtained by dredging, for several years were among the important items. Undeveloped deposits of antimony, magnesite, quicksilver, and limestone have been noted in this county in addition to the foregoing.

    "In forty-eighth place, commercial production during 1919 was as follows:

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

    Stone, miscellaneous; ---, $40,350

    Merced 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. 190. Merced County , 1916 Map

Merced County - List of Stone Quarries, Etc.*

(* Please note this list does not include sand or gravel quarries.)

  • Gustine, Merced County, California - San Luis Reservoir State Recreation Area State Recreation - Stone Quarry (State recreation area located 33 miles East of Highway 101 from Gilroy - Park headquarters: 31426 Gonzaga Road, Gustine, CA 95322)

    The previous version of this web site indicated there was a stone quarry in the area. The current version does not.

  • Merced County, California - the Dickenson Quarry (Sandstone) (From The Structural and Industrial Materials of California, Bulletin No. 38, California, State Mining Bureau, San Francisco, California, 1906.)
  • "Dickenson Quarry, in T. 9 S., R. 16 E.; S. W. Dickenson, owner. A small quarry of a medium-grained, gray sandstone, which has been developed only in a small way."

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