Recent geological and engineering investigations at Hamilton, Ontario, have resulted in the discovery of buried plant-bearing beds in deposits of Lake Iroquois and Lake Ontario. Fossils in these beds indicate cold, shallow-water conditions of sedimentation for the earlier-deposited beds and warmer conditions for later-deposited layers. Radiocarbon dating of buried wood suggests that Lake Iroquois was formed during the retreat of Port Huron ice. The Valders drift boundary is inferred to be north of Lake Ontario. Lake Ontario probably began over 10,000 years ago.
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Karrow et al. (1961) studied this question.
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