Toronto Island
Toronto Island is part of a sand-bar which begins on the mainland near Woodbine Avenue and extends westward for about 9 km before turning northward toward the main shore. The building of the bar began with the formation of Lake Ontario about 8,000 years ago. Eroded from the Scarborough Bluffs, the sand was shifted westward by wave action during easterly storms. Eventually a long curving peninsula was formed, creating the large natural harbour on which Toronto was founded. The bar's westward growth was halted shortly after 1858 when a storm opened a large gap near the eastern end of the peninsula. The island thus formed became one of Toronto's major recreational areas.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.