Slate. Reference: Bulletin 38. Slate was first produced in California in 1889. Up to and including 1910 such production was continuous. Many large deposits are known in the State, especially in El Dorado and Mariposa counties, but the demand is not what it was a few years past. A complete record of amount and value of slate produced in California follows: Reference: State Mineralogist Report XII. Bulletin 38. Miscellaneous stone is the name used throughout this report as the title for that branch of the mineral industry covering crushed rock of all kinds, granite, paving blocks and sand and gravel. The foregoing are very closely related from the standpoint of the producer. The quarry which produces granite blocks this year may have a commercial output of crushed rock next, or its product may regularly consist of both classes of material. Thus it has been found to be most satisfactory to group these items as has been done in recent reports of this Bureau. In so far as it has been possible to do so, granite and crushed rock production has been subdivided into the various uses to which the product was put. It will be noted, however, that in both instances a very large percentage of the output has been tabulated under the heading "Unclassified." This is necessary because of the fact that many of the producers have no way of telling to what specific use their rock was put after they have quarried and sold the same. Stone, as well as some other structural materials, shows a decrease for 1914. The total production was valued at $4,860,357, at the properties. As has been the case for several years past, Los Angeles County led all others by a wide margin, with an output valued at $953,434; Marin second, with $490,137; Alameda third, with $381,135; and Contra Costa fourth, with $308,727. |