This Millstone
This millstone, brought from England on the schooner 'Kingston' to the town of York 1832, was used for grinding grain in the historic windmill of Gooderham & Worts. The windmill stood 20 m southwest by south of this point. It was the eastern limit of the famous 'Old Windmill Line' on which the original plan of the city of Toronto was based.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.