A swamp in southeastern New Brunswick contains up to 10% Cu (dry weight) in forest peat. This mineralization is unusual in that the metal is not present in megascopic lumps of native Cu but, rather, is invisible and appears to be in inorganic combination. Factors responsible for the movement of the metal in the mobile state are clearly diffusion, capillarity, evaporation, and the growth of frost crystals. The phenomena liable for the fixation of the Cu are less apparent. Vegetal concentration, sorption, and coprecipitation have no doubt produced minor modifications of the dispersion pattern. The dominant factor effecting the immobilization of the metal, however, appears to be sequestration of the Cu by the organic sediments, thereby forming a chelate compound. On the basis of this study, the only value that can be assigned to the activity of microbes is, possibly, a catalytic effect, speeding the formation of the Cu compound already stable under the chemical conditions imposed by the environment.