This is what a mill was like 100 years ago, this is Roblin’s Mill now relocated to Jane & Steeles in Black Creek Pioneer Village, where it can be seen restored.
http://blackcreek.ca/buildings/roblins-mill/
Upon his arrival in York, Simcoe was keenly aware of the need for a lumber mill and grist mill in the area. He had constructed a sawmill on the west bank of the river near present-day Bloor Street in 1793, which was operated by John Wilson. In 1797 Simcoe managed to get a grist mill established on the Humber River. It was owned and operated by John Lawrence. Over the years, numerous mills have been operated along the river by such men as William Cooper, W. P. Howland, Thomas Fisher, John Scarlett, William Gamble and Joseph Rowntree. The last grist mill on the Humber, Hayhoe Mills in Woodbridge, closed in 2007.
Background re Mills
A US historian has commented that in early American towns, mills and their dams were well-understood technologies that had existed for many generations, authorized by the townspeople and used for the common good. The mills and their technology existed in a social system that emphasized their status as shared resources for community use. There was a reciprocal give and take between people who had different interests in the society, both in social customs and in common law. Millers were given special incentives to move to new towns and help them grow. In return, they were responsible for keeping the mills running and available to everybody, and for responding to their neighbors when they changed the flow of streams in ways that caused problems. In return, many millers enjoyed what amounted to a local monopoly on sawing wood and grinding flour. Although other millers were rarely prohibited from opening competing mills, there was only so much need and there was only so much water power. But there were always new towns needing millers, so common customs and common sense were effective ways to regulate early mills.
Also this, from another source: Watermills were usually built beside streams or rivers to use them as a water supply. Very often these supplies were improved by the provision of mill races and weirs to help overcome the problems of different seasonal water levels. Many of the weirs seen on rivers today were originally built to help control water levels for watermills.
Mills on the Humber in or near Mount Dennis
In 1793, when Governor Simcoe travelled up the valley, he ordered his Queens Rangers to build a sawmill on the site of what is now the Old Mill (replaced in 1834 by a gristmill). Another very early mill was built in Weston by James Farr in the 1790s. Over time there were 164 different mills built on the Humber: 103 sawmills, 43 gristmills and 18 woolen mills.
In 1831 John Scarlett built a mill on the west bank of the Humber just south of the Richview Side Road. His son Edward operated this mill until it was sold to Mathew Canning in 1871. This would be opposite our walk area.
In 1846 a new saw mill was built by Mr. Samuel Scarlet in York Township, about a mile above Lambton, but he abandoned it in a few years for a new site across the river, where greater water-power was obtainable. Further up the stream Mr. Joseph Dennis put up a saw-mill in 1844, which afterwards became the property of his son, Henry Dennis, who converted a portion of it into a flax-mill. James Williams had a carding and fulling mill a little distance above, which was destroyed by fire in 1865. These would have been within our walk area.
Maps from around 1850 show three different mills built by local landowners in or near Mount Dennis: Scarlett built one just south of what is now the Scarlett Road bridge, Dennis’s sawmill (which by 1851 was processing 4,000 feet of lumber per day) appears to be near where the Eglinton bridge is today. and Scarlett owned a second mill a bit further north – perhaps where the weir is today.
Wikipedia’s entry about John Scarlett includes this: “By 1815 Scarlett had a lumber and a grist mill on the east bank of the Humber River and a saw mill on the west … In 1846 Scarlett sold his mills to William Pearce Howland, a move which proved to be well timed. Changes in colonial trade laws, the decline of timber resources in the Humber Valley and continued destruction from flooding spelled an end to the prosperity of millers shortly thereafter”. In 1878 the Dennis mill was destroyed in a flood and never rebuilt. One writer as said that “the introduction of steam power transformed the Humber Valley from an industry of bustling mills to a place of leisure and recreation.”
Gravel, sand, clay, and shale were all removed from Mount Dennis valleys. They were used to make brick, building foundations, cement, and transport across Toronto, the most famous being Maple Leaf Gardens. This altered the valley shape, the City then built berms to fill the valleys, and the inadequate passages through those berms now cause massive flooding.