This geochemical map shows drainage basins in which either anomalous lead, zinc, or both lead and zinc values were detected in at least one of four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The anomaly patterns were derived from the point-plot maps of lead and zinc distribution in the individual sample media. (Curtin, Day, O'Leary, Marsh, and Tripp, 1976a, b). Background data were disregarded for each of the two metals. Weakly anomalous data for all media (small black symbols) were assigned the number 2; strongly anomalous data for all media (large black symbols) were assigned the number 3. These new data were then summed or "stacked" for each metal so that all sites showing anomalous values in one or more of the sample media had a numerical rating that ranged from 2 (weakly anomalous value in one sample media) to a possible 12 (strongly anomalous values in all four sample media). The summed data were ranked into the three groups shown in the explanation. The drainage basins showing anomalous values were outlined according to these groups. As a final step the composite lead anomaly map was then superimposed on that of zinc to give this composite lead-zinc map.