a species of earth found near Rome, Naples, and Florence, of which the following account is taken from the New Translations of the Royal Academy of Sciences at Stockholm for the year 1797:

Near Naples the lapis fungifer is found in the chalk-hills like a white talcstone, intermixed with a great many fine roots of shrubs; and near Florence there is a species of it, consisting of hardened turf, which is dug up near volcanoes. The author made experiments with a piece procured from Italy, and found that 180 parts contain from 45 to 46 siliceous earth, 23 argillaceous earth, 7 calcareous earth, and 20 calx of iron, with some white magnesia and vegetable alkali. It is well known, that when this friable species of stone is preserved in cellars and moistened with water, it produces abundance of eatable mushrooms, which in Italy are highly esteemed and brought to the first tables. Hence the origin of its name.