Illinoian to Late Wisconsinan stratigraphy at Woodbridge, Ontario

Near Woodbridge, northwest of Toronto, Ontario, a 15 metre-high railroad cu t and associated borrow pit, first excavated in 1962, exposed a multiple ti ll sequence and intervening fossiliferous sediments. Work over the next 35 years revealed that Illinoian York Till, early Wisconsinan Sunnybrook Till, and late Wisconsinan Humber till, Halton Till, and Wildfield Till are inte rbedded with fossiliferous sediments equivalent to the Sangamonian Don Form ation, early Wisconsinan Scarborough Formation (> 50 ka BP), and middle Wis consinan Thorncliffe Formation (45 ka BP). A complex periglacial record dis plays multistage fossil frost wedges, indicating intervals of severe climat e in late Illinoian and early Wisconsinan time. Cored boreholes indicate de ep gravel below and a till on Ordovician shale bedrock (Georgian Bay Format ion). Vertebrates, molluscs, ostracodes, insects, and plants (diatoms, wood , seeds, pollen) indicate mostly cool conditions (boreal to tundra) for int erstadial sediments. Interglacial conditions are represented by vertebrates , molluscs, and plants above York Till. Many taxa are new to the Quaternary of the Toronto area.