AGE AND PALEOECOLOGICAL SIGNIFICANCE OF AN EARLY POSTGLACIAL FOSSIL ASSEMBLAGE NEAR MARATHON, ONTARIO, CANADA

Organic materials recovered from deltaic deposits confined to the Blac k River Valley near Marathon, Ontario, provide information on lake-lev el history and local ecology for the region. Radiocarbon samples provi de the first age determinations (ca. 8200 BP) for the post-Minong III- IV lake phases along the northeast corner of-the Lake Superior basin. A minimum of 49 Coleoptera taxa and 22 vascular plant ta;a indicate co niferous:forest and riparian communities. Overbank deposition along ri vers flowing from the ice margin provided temporary ponds: colonized b y sedges and other aquatic plants and animals. Many records for both a nimals and plants illustrate occurrences of western and Arctic disjunc t species in early Holocene time. Some ''western'' Coleoptera might st ill be present as disjuncts in the Marathon region.