Total annual production of gypsum in California since such records have been compiled by this Bureau is as follows:

Reference: State Mineralogist Reports II, XII, XIII. Bulletin 38. Infusorial, or diatomaceous, earth-sometimes called tripolite-is a very light and extremely porous chalk-like material composed of pure silica which has been laid down under water and consists of the remains of microscopical infusoria and diatoms. Its principal commercial use is as an absorbent. It is also a first-class non-conductor of heat, is used in the manufacture of scouring soap and polishing powders, and in making some classes of refractory brick. The most important deposits in California thus far known are located in Los Angeles, Monterey, Orange, San Benito, San Bernardino, San Luis Obispo, Santa Barbara, Shasta, and Tehama counties.

During 1914 there were four actively operated quarries producing this material, and three additional properties were reported idle.

Production during that time amounted to 12,840 tons, valued at $80,350.

The first recorded production of this material in California occurred in 1889; total amount and value of output, to date, are as follows:

It will be noted that the average price varies widely from year to year. This fact is true in case of many of the industrial materials. The quality of the product fluctuates, as does the demand; when both are favorable the maximum price obtains.

Limestone.

Reference: State Mineralogist Reports IV, XII. Bulletin 38. Limestone was produced in ten counties during 1914, to the amount of 572,272 tons, valued at $517,713. This amount does not include the limestone used in the manufacture of cement or in lime, but accounts for that used as smelter flux and other manufacturing processes, and a considerable amount which is used as road metal.

Distribution by counties of the 1914 output is as follows:

In the early reports of this Bureau values for lime and limestone were not segregated. The following tabulation shows the total combined value of such material since records for the State were first compiled, in 1887, to date:

Reference: State Mineralogist Reports XII, XIII. Bulletins 38, 67. Manganese is reported to exist in many localities in the State; but past production, particularly since the discontinuance of the chlorination process in the metallurgy of gold, has been relatively unimportant. During 1914 there was reported a production of 150 tons, valued at $1,500. Manganese is used in the steel industry; in the manufacture of paint, glass, pottery; in the chemical laboratory, etc. Local demand is very small. The advent of electricity in the metallurgy of iron promises to enlarge the field for the use of the manganese deposits of California, and another year should show a marked increase in the output of this substance, particularly in Mendocino and Alameda counties.

The production of manganese ore in California annually since 1887 follows:

Reference: State Mineralogist Report II. Bulletin 38.

No production of mica has recently been reported. Production in previous years is as follows:

Lithia mica, utilized in the manufacture of artificial mineral water, fireworks, etc., was mined and sold in San Diego County during the years 1899-1905 inclusive, but there has been no commercial production. since the latter date.

Lithia mica total production in the State is as follows:

Reference: State Mineralogist Reports XII, XIII. Bulletin 38. Mineral paint was produced in California in 1914, from two counties, as follows:

Deposits of more or less importance are located in Calaveras, Kern, Lake, Los Angeles, Kings, Nevada, Riverside, Sonoma, and Stanislaus counties.