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Home > California > CA - Quarry Links & Photographs > Sierra County
"Granite and Granite rocks occupy a prominent place in the geological structure of Sierra County, especially in the eastern and south-central portions. No exploitations with a view to determining its structural qualifications has been undertaken."
"Basaltic lava occurs in Sec. 29, T. 21 N., R. 10 E., 2 miles east of Morristown; also in Sec. 34, T. 22 N., R. 10 E., at Mount Filmore, in the northwestern part of the county; also in Sec. 27, T. 19 N., R. 14 E., at Weber Lake, in the central part of the county. This stone is adapted for building purposes, resistant exposure to the weather, and may be secured in massive sizes. It can be worked with the ordinary stonecutter's tools, takes a fine polish, and has been employed in local construction and for monument work in local cemeteries."
"Three distinct ledges of limestone occur in the central part of the county, between Downieville and Sierra City. The first is encountered about 3 miles east and northeast of Downieville, extending from Sec. 13, T. 20 N., R. 10 E., in a southwestern course through Secs. 19, 30, 32, T. 20 N., R. 11 E.; the second, 2 miles farther east, has a north and south course through the W. ½ of Sec. 27, T. 20 N., R. 11 E.; the third is between Loganville and Sierra City extending in a southeasterly course from the center of Sec. 30, through Sec. 29 and into Sec. 32, T. 20 N., R. 12 E. This last named is the most important of the three ledges in point of quality. In November, 1904, lime was being burned from the limestone taken from this ledge for structural use in the construction of a cyanide plant for the Sierra Buttes mine. Thirty years ago lime was burned from the limestone taken from the ledge nearest Downieville."
Area: 923 square miles.
Population: 1,783 (1920 census)
Location: Eastern border of state, just north of Nevada County."Sierra County reported a mineral production of $292,950, consisting mainly of gold and silver, during the year 1919, as compared with the 1918 output, worth $331,501, the decrease being due to chromite. Considering gold output alone, this county stands tenth; and as to total mineral yield thirty-third.
"Aside from the metals itemized below, Sierra County contains deposits of asbestos, chromite, copper, iron, lead, platinum, minerals, serpentine, and talc.
"Commercial production for 1919 was as follows:
(Headings for the information below are: Substance, Amount, and Value.)
Gold, ---, $290,000 (estimated)
Silver, ---, $2,200 (estimated)
Stone, miscellaneous, ---, $750
(Total value) $292,950
| Sierra 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. 184. |  |
Topography"The district is very rugged and mountainous. Sierra City is in the narrow valley of the North Fork Yuba River at an elevation of 4300'. It lies at the southern base of the Sierra Buttes, which rise to an elevation of 8615' in a distance of two miles. To the south the region rises abruptly from the river to a flat-topped ridge, 2500' above the river."
"Numerous deposits of limestone have been noted in the Carboniferous rocks extending northwest across Sierra County. Most of them are along the eastern side of the metasediments from Loganville, a little west of Sierra City, to Eureka Peak in Plumas County. In this region the limestone is magnesian, of light or dirty gray in color, and differs from the high-calcium limestone farther southwest, in color, composition, and probably in age, though the latter is not known to have been definitely determined. No fossil evidence has been found in these magnesian limestones. A chemical analysis by the U. S. Geological Survey of a sample from a limestone deposit north of Loganville showed the following:SiO2, 4.9 percent"Some of this magnesian limestone is associated with the iron (magnetite) deposits in the high mountains near the Plumas County line.
Iron oxide, 0.36 percent
Lime, 31.33 percent
Magnesia, 19.61 percent"None of the deposits in Sierra County are near enough to a railroad to have commercial value at present. The largest and most accessible lens is about 5 miles east of Downieville, on the state highway."
(* Please note this list does not include sand or gravel quarries.)
"Immediately east of Downieville the roadcuts are in a belt of black slates which have been quarried for local use as a building stone. The slates are full of quartz veinlets which have invaded the series along the bedding planes. These slates closely resemble the Mariposa slates of the Mother Lode but have been assigned to the Calaveras formation by H. W. Turner…."
"Indian Valley public camp, the second of a series of excellent camp sites beside the (Yuba) river, is located two miles east of the bridge. Half a mile before reaching the camp is the granodiorite-meta-volcanic contact. The Granodiorite, which is well exposed in a quarry east of Indian camp, is much like the average granodiorite south of Camptonville…."
"Soapstone of a structural character has been quarried for local use at the Alaska Quartz Mine (George St. John, Pike City, superintendent), near Pike City, in Sec. 8, T. 18 N., R. 9 E. This dike of soapstone is 300 feet wide, strikes nearly north and south, and is apart of the belt mentioned above (see Butte County, page 350). The furnaces and the foundation bed for the hoist were constructed twenty years ago of this soapstone. These structures are still standing, and have been recently used. The soapstone is of whitish tint, weathers brown, resists the elements, is hardened by the action of fire, but is wasted by friction with other material. It is easily cut with a common saw. Other structures have also been satisfactorily constructed of this material."
"Three distinct ledges of limestone occur in the central part of the county, between Downieville and Sierra City. The first is encountered about 3 miles east and northeast of Downieville, extending from Sec. 13, T. 20 N., R. 10 E., in a southwestern course through Secs. 19, 30, 32, T. 20 N., R. 11 E.; the second, 2 miles farther east, has a north and south course through the W. ½ of Sec. 27, T. 20 N., R. 11 E.; the third is between Loganville and Sierra City extending in a southeasterly course from the center of Sec. 30, through Sec. 29 and into Sec. 32, T. 20 N., R. 12 E. This last named is the most important of the three ledges in point of quality. In November, 1904, lime was being burned from the limestone taken from this ledge for structural use in the construction of a cyanide plant for the Sierra Buttes mine. Thirty years ago lime was burned from the limestone taken from the ledge nearest Downieville."
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