In St. Marys, Ontario, two former limestone quarries sit on opposite sides of Water Street South. The eastern pit is a supervised swimming venue in summer. The western pit permits fishing and human-powered boats, but not swimming. What makes the split more surprising is a detail on the town's own website: an underwater tunnel connects the two bodies of water, and fish can move through it. The water has a connection that the public rules deliberately do not share. [1–3]
This is not a story about one quarry succeeding while the other failed. Both have been remade as public places. But their different afterlives—one a swimming quarry for generations, the other a newly improved waterside landscape—show how something as ordinary as a road, a shoreline and a safety by-law can shape what a town chooses to keep from its industrial past.
The road the quarry company could not have
The story begins before either hole held a summer crowd. Limestone near the Thames River helped give St. Marys its "Stonetown" character: nineteenth-century buildings used stone from the surrounding area. According to the town's historical-landmarks account, several smaller operations grew into the Thames Quarry Company, producing building blocks, crushed stone and lime. Quarry operations on either side of Water Street South were joined by a tunnel under the road. [1, 4]
The company wanted more than a tunnel. In 1914 it asked the town to close the Water Street route so limestone under the road could be extracted. Town council refused, deciding the route was too important. A municipal decision about the usefulness of a street therefore left a lasting line through the quarry landscape. [1]
That line can still be read in the names on official documents. A 2018 St. Marys quarry by-law defined the east pit as the Swimming Quarry and the west pit as the Fishing Quarry. It also restricted swimming in the east to areas and times with municipal lifeguards; at the time, the western site was limited to fishing, without boating or swimming. [5] The two waters belonged to the same industrial story, but municipal rules treated them as distinct public spaces.
From limestone to lifeguards
When did the stoneworks become a public swimming place? There is no need to invent a single dramatic shutdown. The town's pages summarize the decline somewhat differently: one calls the swimming quarry a site that closed in 1920, while its longer historical-landmarks record says the Thames Quarry Company ceased operations in 1930, with crushed stone sold from existing stock afterward. The latter describes pumps being removed and groundwater filling the excavations. The safest conclusion is that quarrying and stockpile disposal ended in stages, not that one date explains the entire transformation. [1, 2]
Swimming began before the town owned the property. The municipal quarry history says the water-filled site was already popular with residents in the 1930s. In 1945, the town purchased both quarries and about 50 acres of land; its recreation page records a purchase price of $2,200. [2] The decision created the possibility of a public recreation system, but acquisition alone did not build it.
The town's historical-landmarks record supplies the telling small details. Don Fletcher was hired as a lifeguard in 1946 for $25 a week; his brother Doug handled admissions and concessions. In 1950 the town began charging admission, and local children could buy a season pass for 25 cents. [1] A former stone pit was becoming a place with a staff, rules, equipment and an ongoing operating budget. That practical work is as much a part of the transformation as the image of blue water inside high rock walls.
A community museum contribution to the Canadian Community Stories project separately describes the St. Marys quarry as a limestone site rehabilitated for swimming and recreation and becoming especially popular after the Second World War. The gallery catalogues an undated photograph of swimmers at the quarry from the St. Marys Museum and Archives. This article does not reproduce that image: a publicly accessible archive listing does not itself grant republication rights. [6]
The other side of the road did not stand still
Meanwhile the west side retained a different identity. For years it was commonly called the Fishing Quarry. Unlike the more familiar east-side swimming facility, the west side was not being maintained as a second supervised swimming pool. The labels in the 2018 by-law are evidence of a policy distinction, not proof that officials in 1945 foresaw every later use. [3, 5]
The contrast became clearer in 2026, when St. Marys set about improving the West Quarry. Its April project notice described removal of old concrete and steel, control of invasive growth, changes to fencing, safer access and a plan for passive recreation. The town described the cleanup as a partnership with the Ontario Aggregate Resources Corporation (TOARC). A contemporaneous independent news report also described planned retention of healthy trees and replacement planting for those removed. [7–8]
The town reports that the West Quarry reopened in July 2026 after work that removed approximately 900 cubic metres of waste concrete and 7,500 pounds of steel material that the town described as hazardous waste, alongside changes to green space and access. These figures do not describe a new swimming installation. They show the less glamorous labour required to turn industrial remains into a different kind of public amenity. [3]
And the rules changed. As of October 24, 2026, the town's published guidance for By-law 28-2026 permits fishing and human-powered watercraft—canoes, kayaks and paddleboards—at the West Quarry between dawn and dusk, while swimming remains prohibited. The town's current guidance also warns that there is no official launch dock. [3] The western site gained ways to enjoy the water without being made interchangeable with its neighbour.
One tunnel, two decisions
The underwater tunnel makes the division especially revealing. The town says carp, pumpkinseed and rock bass can move between the quarry waters through it. [3] A fish has no reason to recognize the town's east-versus-west recreation categories. People do: on one side, municipal swimming rules apply; on the other, a different set of permitted activities and access precautions governs.
The sources do not establish that the tunnel made either side safe or unsafe for swimming. Nor do they establish why the east quarry, rather than the west, became the principal supervised swimming site at every stage. The historical records do not establish whether one lasting physical difference determined which pit became the supervised swimming site. The town's modern restrictions describe permitted uses, not proof of the original decision's rationale. These decisions belong to different eras and should remain separate in the telling.
What the records do show is a sequence: a town defended a street in 1914, acquired two flooded pits in 1945, built up supervised swimming in the decades after, and in 2026 invested in making the western waterside usable on its own terms. This was not one grand design carried out from start to finish. It was more than a century of new decisions made around the inherited shape of a quarry. [1–3, 5, 7]
St. Marys did not erase its limestone history when it stopped extracting stone. It kept the pits, the road and the tunnel—and kept debating what each part should be for. In that sense the most surprising fact is not that one hole became a swimming pool. It is that two connected holes could belong to the same town and still tell such different stories about public space.