POLLEN ANALYSIS OF THE MICHILLINDA PEAT SEAM

The Michillinda peat seam is exposed along the shores of Lake Michigan, near Muskegon and thus lies about 60 miles north of the South Haven seam studied by Zumberge and Potzger (1955). It consists of about 50 in. of peat lying on gravel and sand over silt and is overlain by dune. The basal layer has been dated at 5250 B.P. (M-473) and the top at 4100±250 B.P. (M-472). It thus represents about 1000 yr of accumulation and approximates, perhaps accidentally, the rate of peat accumulation calculated by Sears and Jensen (1933) for the Erie basin. We are indebted to Professor James Zumberge for the opportunity to study this material, and to the National Science Foundation for financial assistance. Results of our analysis are shown in detail in table 1. As indicated by the column of total counts, pollen was very scarce in some layers, the peat at certain depths being heavily diluted by sand as shown in figure 3. Carbonized plant remains are also abundant, particularly in the sandy layers, but whether they are due to fire or decomposition (muck formation) we cannot say. Our main con-clusions have been drawn from those spectra representing a count of more than 100, although in general the lower counts confirm the higher ones