One of the surprising things of the "Ice Age" is that about 10,000 to 12,000 years ago, a large embayment of the Atlantic Ocean extended up the St. Lawrence Valley into southern Quebec and eastern Ontario. The seashore extended across from the Lake Ontario basin near Kingston northeastward near Carleton Place to the Ottawa Valley as far as Pembroke. All of Ontario east of that shoreline, including Ottawa, and much of the St. Lawrence Valley of Quebec was flooded by sea water to depths as great as 100m (Fig. 1).
