FOSSIL

remains of plants and animals embedded in minerals; term includes foot-marks of animals. Formerly called petrifactions, owing to organic parts being replaced by, petrifying solution; thus the gradual decay of organic matter allowed each cell to be replaced, and corals, leaves, etc., showing comlete structure, are found. Fo il forests bare been found in England and elsewhere. The most notable examples are in the southwestern part of the United States. In Arizona is the famous ‘petrified forest,’ where all the trees have been fo ilized into mineral matter. Fo il ferns show the development of the plant from Devonian Period.