Buried under more than 50 wineries, 10 golf courses, a college and a university, shopping malls, an outlet mall, and around 447,000 residents lie rocks that predate the dinosaurs by almost 350 million years. Standing on top of the Niagara Escarpment and looking out over the Queenston Quarry, it’s impossible to imagine what this land looked like so long ago.

More recent than that, but even harder to picture as the wind blew clouds fiercely across the sky, from 23,000 to 12,000 years ago the land we were standing on was covered in a glacial sheet of ice between 1 to 3 miles thick. That was the last of three successive glaciers that changed the shape of everything in southern Ontario.

Ice of a mile thick would exert 150 tons per square foot of pressure — it’s been estimated that the weight of the Late Wisconsin Glacier pushed the land 200 feet downward. When a glacier retreats the land begins to push back up, and in the Niagara basin it created the 11th and 13th largest lakes in the world: Lake Erie and Lake Ontario. We took visiting friends from Australia to the beach along Lake Ontario, and they asked if they were looking at the sea, not a lake.

At 445 million years ago, the entire area was a sea — the Michigan sea. tropical, and full of small creatures that, when they died, deposited enough calcium carbonate shells to form thick layers of sediment that slowly turned into layers and layers of limestone. It was this very limestone that, over 400 million years later, would become the basis for both a quarry and a cement company in 19th century Queenston, originally named Queen’s Town by the British soldiers occupying the area during the War of 1812, then shortened to Queenstown. The area was actually settled in the 1770s by Loyalist refugees and immigrants from the United States.

The Queenston Quarry was founded in 1837, supplying the stone for many of Ontario’s cities. The Royal Ontario Museum, Queen’s Park and Union Station in Toronto were all built with Queenston stone.

In 1882, ‘Isaac Usher & Sons’ opened a cement operation at the top of the escarpment running past the quarry. They mined a layer of stone with components similar to cement, firing it in huge limestone kilns, Once finished in the kilns, the product was ground into a powder and sold as Red Star cement. It was the first such plant in Ontario. In 1898, the Ushers issued a 33-page pamphlet entitled “Practical Hints on the Use of Queenston Cement” can still be found in libraries as far away as Australia.

The Ushers closed their doors in 1905, and their kilns and ovens began to disappear under the rich soil and forests of the escarpment. Luckily they didn’t vanish entirely, and partially-restored remnants can still be seen today on a strenuous hike along Queenston Heights.

The trail starts off innocuously flat.

After a while you come across a strange structure poking its head out of the trees. It’s an old metal tower that was apparently used by the Department of National Defence to intercept foreign radio waves during the Cold War.

As we wound our way through the trees, we found two of the pit ovens used to treat the raw limestone.

The remarkable stone structure of the escarpment could be seen in a breathtaking natural amphitheatre about half of the way to the actual kilns.

After that point the trail becomes extremely hilly, and it was treacherous to hike on a fall day after several days of rain had littered the ground under our feet with thousands of wet leaves.

If you want to do this hike, I’d recommend spike-tipped hiking poles at the very least. Even with sturdy treads at the bottom of my hiking boots, I was happy to take the bypass where dirt steps have been added.

It took us a good 45 minutes to reach the kilns.

During excavation of the Third Welland Canal, it was discovered that a layer of natural cement rock underlay the blue dolomite running across much of the Niagara Escarpment. Usher leased the land from the owner of the property in order to build three kilns (later increased to six), 40 feet high by 10 feet in diameter. Two of them can be seen in the photo below.

The kilns were constructed of rubble and lined with fire brick and fire clay.

At the bottom, steel rails formed grates on which firewood and soft coal were layered with the cement rock and soft coal until the kiln was filled. The firewood was then lighted and kept burning as more coal and rock were added from the top. Below you can see remnants of the steel rails in the roof of the bottom opening.

I haven’t so far been able to find a definitive description of the process, but the resulting cement powder was packed in barrels produced at the warehouse. Each barrel held 350 pounds of powder.

The Queenston Cement Works was a going concern for several years, supplying cement for the St. Lawrence/Welland and Sault Ste. Marie Canals. The adhesiveness of Ushers’ cement was so high that in 1932 , during the blasting to remove the old Welland River Aqueduct, which carried the Welland River under the Canal, the stone itself typically broke before the cement bond did.

Unfortunately the Ushers weren’t able to compete with the lower pricing of Portland cement, developed in England earlier that century. Portland’s base materials were lower cost and widely available, and this cement remains in wide usage to this day. Queenston Cement also took 24 hours to dry, as compared to only 6 hours for Portland.

The cement stone was mined not far from the kilns in a system of caves that can still be seen.

When you look in through one of the two openings, you understand how difficult this mining must have been.

The caves are squatter than a person’s height, and the limestone rock bearing down on them is full of cracks. The tunnels are also flooded much of the time.

People have climbed down into them to have a look around, but from the number of cave-ins that have been spotted not far from the entrances, it’s not a stunt I’d recommend.

The Queenston Quarry itself was operated until apparently around 2008; its last owner as such was Lafarge Canada. After that it was bought by a developer, the Queenston Quarry Reclamation Company, who’s transforming the land into a golf course and residences. And so, another piece of Niagara history changes hands and develops a new face.