‘There are other limestones in Canada but this is a unique deposit,’ quarry co-owner says

A large block of stone hangs from chains in the middle of a black and white photo with men standing on either side.
August Gillis, founder of Gillis Quarries, is in the foreground at the right of a slab of Tyndall Stone in this undated photo. (Supplied by Gillis Quarries)
A building material used in Manitoba for nearly 200 years, from trading forts to the modern-day architecture of the Canadian Museum for Human Rights, now has international recognition on par with Carrara marble used in ancient Rome.

Tyndall Stone — a fossil-laden limestone dating back 450 million years — has been designated as a global heritage stone resource by a subcommission of the International Union of Geological Sciences.

The cream-coloured stone often has a tapestry-like mottling from marine organisms that lived at the bottom of a tropical sea that once covered the area, making it a popular feature in architecture.

Canada is the only source in the world for the stone, and Manitoba is the only place it is quarried.

Three people in the distant centre of the photo can be seen cutting large square slabs of stone.
Tyndall Stone is seen being being cut at Gillis Quarries. Each slab weighs about 300 pounds and yields several pieces, according to Donna Gilllis. (Graham Young/Manitoba Museum)

“It’s an honour. We’ve always said it’s not like other limestones. There are other limestones in Canada but this is a unique deposit and the fossilization is really different,” Donna Gillis, fourth-generation co-owner — along with her brother Keith — of the Gillis Quarries in Garson, Man., about 25 kilometres northeast of Winnipeg.

“We’ve got that as being something special,” she added about the mottling.

Founded in 1910 by August Gillis, the family-operated quarry is the only one in the world mining the stone. There were a handful of others — all in Garson — but the Great Depression claimed most while others retired. Gillis then acquired the properties.

A black-and-white photo of a man in a thick sweater and old-style hat carving a piece of stone.
A man works on the finer detailing of a piece of Tyndall Stone in the 1930s. (Supplied by Gillis Quarries)

Tyndall Stone was discovered in 1823 by Major Stephen Long of the Hudson’s Bay Company, who first noticed an exposure along the banks of the Red River near Selkirk.

The stone was first used to build the warehouse and walls of the HBC’s Lower Fort Garry in 1832 and the St. Andrew’s Anglican Church in 1845, both of which remain standing and in use.

But it wasn’t until 1894 that the major deposit was discovered in Garson by farmer who hit an impenetrable layer while digging a well. The first large quarry opened in 1898, and the stone got its name because rail shipments were sent from the nearby community of Tyndall.

The name is now trademarked by Gillis Quarries.

Grey and cream-coloured marks are shown on a stone, along with fossils from ancient marine animals.
Fossils and mottling on Tyndall Stone on the exterior of the Law Courts building in Winnipeg. The grey mottling is preserved tunnels originally made by burrowing marine animals seeking food and refuge from predators. The spaces were eventually filled by replaced by dolomite crystals. (Fernand Detillieux/Radio-Canada)

August Gillis first became involved by cutting the stone in a small shop in Winnipeg in 1910, before buying a Garson quarry in 1915.

The stone can now be found in buildings across Winnipeg — the legislative building, the former Hudson’s Bay Building downtown, city hall, Manitoba Museum, Winnipeg Art Gallery, Law Courts, Westminster United Church, Union Station, St. Boniface Cathedral, Civic Auditorium and many more.

It really is a signature of the city, said Graham Young, curator of geology and paleontology at the Manitoba Museum, who spearheaded the nomination along with Brian Pratt, a geology professor at the University of Saskatchewan.

“It’s great to get some recognition for Tyndall Stone on the world stage. It’s been such a significant stone across Canada and the building of this country,” he said.

An aerial image shows a stone quarry, with areas filled with water.
An aerial view of the Gillis Tyndall Stone quarry, seen in 2017. (Submitted by Gordon Goldsborough)

It’s not uncommon to see people pointing out fossils in the stone on buildings or stair slabs made of Tyndall. But it’s equally special for those mining the stone, said Gillis.

“When you’re cutting into a solid piece of stone you don’t know what you’re going to find. It’s a mystery,” she said.

“We might hit something like, wow, this is really different, this is quite amazing. And then there’s some we’ve seen before, but you always see them in different ways, different angles, different orientations in the stone.”

Outside of Manitoba, the stone has been used for the Canadian Parliament Buildings in Ottawa, Canadian Museum of Civilization in Quebec, Saskatchewan legislative building, Banff Springs Hotel in Alberta and Empress Hotel in B.C.

Overseas, it is in Canada House in London, England, the Canadian Embassy in Berlin, and private homes in Australia and Japan, according to Gillis.

“That’s one of the reasons it did make it on the global heritage stone resource list, because it has had widespread use and can be used in a variety of ways,” she said, noting she reviewed the submission before it went to the committee.

The rounded corner of a stone wall is in the foreground on a trimmed and green grass lawn. The stone wall stretches into the distance where tree branches hang over the top of it.
The stone walls of Lower Fort Garry, and some of the buildings inside, are among the first structures made with Tyndall Stone. (George Penner/Manitoba Historical Society)

Tyndall Stone is the only Canadian stone on the worldwide list, which contains 32 stones designated as heritage resources.

“This designation provides recognition to dimension stones that have broad significance to humanity,” a news release about the designation states.

Young hopes the designation also helps to underscore, for Manitobans, “how lucky we are to have Tyndall Stone, what an interesting material it is and how important geology is to our everyday lives.”

The exterior of a building is seen from its rounded corner, with pillars above the main entrance.
The Law Courts building in downtown Winnipeg is fully clad in Tyndall Stone. (Fernand Detillieux/Radio-Canada)

While the designation might not lead to a rush of new orders, it will probably pique the interest of fossil hunters, Gillis said.

“We already have more paleontologists and geology people that, when they’re often on vacations they like to come and stop in and see if they can kind of take a look around because it is very intriguing,” she said.

Thanks to that access, the Manitoba Museum has built a significant collection of fossils that are used for scientific research, exhibits and programs, Young said.

“There are actually a lot of scientific papers have been published that deal either directly with Tyndall Stone fossils or that include Tyndall Stone as as an important example when understanding ancient environments.”

The exterior of a building is seen, with the name Winnipeg Art Gallery on it.
Tyndall Stone is used on the exterior of the Winnipeg Art Gallery. (Fernand Detillieux/Radio-Canada)