Late Quaternary history and paleoecology of a small oxbow wetland on glaciated terrain were investigated using sediment lithology (cores, bulk samples, backhoedug trenches), ground-penetrating radar, vascular plant and moss macrofossil stratigraphies, and accelerator mass spectrometric radiocarbon dating. A nearly complete mastodon skeleton was recovered from late Pleistocene detrital peat and peaty marl near the top of the sediment sequence. Sedimentation in the basin began with silt and clay over dense cobble outwash transported southward from the nearby Hyde Park Moraine. Overbank sediment deposition occurred between ∼13,000 and 12,220 yr B.P. during a period of tundra vegetation, which ended with a...