This major group includes establishments engaged in manufacturing glass products, cement, structural clay products, pottery, concrete and gypsum products, cut stone, abrasive and asbestos products, etc., from materials taken principally from the earth in the form of stone, clay and sand:

    325.  Structural clay products;

    326.  Pottery and related products;

    327.  Concrete, gypsum and plaster products;

    328.  Cut stone and stone products;

    329.  Abrasive, asbestos and miscellaneous nonmetallic mineral products. (Prior code § 11-20-031)