The earth’s crust gave up crude oil and natural gas to explorers in southwestern Ontario by the 1850s. This view of an oil field is near Sarnia, circa 1910

Gypsum has been mined near Goderich, Ontario since the 1860s. Its popularity as a building material (used by the builders of the Pyramids) is still strong today. Goderich, on Lake Huron, has a deep port for exporting gypsum (1,2/C.J. Humber Collection)