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Study of plant remains found intercalated between two till bodies in Cheboygan County at the northern tip of the Southern Peninsula of Michigan suggests that an open vegetation, floristically similar to a dwarf-shrub tundra or tundra communities within the tundra-boreal forest ecotone was present in this area sometime between 12,500 and 13,300 years B.P. The organic layer that has been correlated with the Cary-Port Huron (Lake Arkona) interstade consists mostly of bryophytes. Eight species of mosses; two kinds of leafy liverworts; achenes from Carex tenuiflora and/or C. trisperma; a perigynium of Carex supina; leaves of the arctic-alpine plants Dry as integrifolia, Salix herbacea, and Vaccinium uliginosum var. alpinum; and Salix twigs have been identified from the deposit. Pollen analysis of the bryophyte bed and associated sediments yielded spectra dominated by nonarboreal pollen, but a significant amount of spruce pollen is also present. Evidence is given that indicates that some of the pollen is rebedded. The macrofossils suggest the presence of distinct communities on wet and dry sites. CONTENTS

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