Tyndall Stone

This image is a composite of Ordovician biotas from Red River and Stony Mountain formations showing columnar aulacerid sponge, elongate orthocone nautiloids, globular receptaculitid, gastropods (snails) and other benthic invertebrates at left, and crinoids (sea lilies), short nautiloids, rugose and tabulate corals and other invertebrates at right. Copyright Manitoba Museum.

About Tyndall Stone

Tyndall Stone is a distinctively mottled and strikingly fossiliferous dolomitic limestone that has been widely used for over a century in Canada, especially in the Prairie Provinces. It comprises 6–8 m within the lower part of the 43 m thick Selkirk Member of the Red River Formation, of Late Ordovician (Katian) age. It has been quarried exclusively at Garson, Manitoba, 37 km northeast of Winnipeg, since about 1895, and for the past half-century extraction has been carried out solely by Gillis Quarries Ltd.

Walls sawn parallel to bedding with honed finish, showing the variation of shapes of dolomite mottling (‘tapestry’). A. Exterior wall. Old bank building, Prince Albert, Saskatchewan. Slabs are 15 x 36 inches (~ 38 x 91 cm) in size. B. Exterior wall showing linear, elongate, irregular, branching, reticulate and circular shapes. Surfaces are 43 cm x 53 cm in size. Health Sciences Building, University of Saskatchewan. C. Interior wall with large sinuous mottle (across middle) overprinting curvilinear burrow. Mottle is 1 m in length. Health Sciences Building. D. Exterior wall showing relatively narrow mottles, with cluster (centre) of gastropods probably belonging to Hormotoma. Health Sciences Building. Scale bar is 3 cm.

Tyndall Stone Buildings Around Saskatoon

In the early years, Tyndall Stone was used almost exclusively in the Prairie Provinces of western Canada. Besides the Saskatchewan and Manitoba legislative buildings, it has been used in many other government buildings such as courthouses, post offices, land titles buildings, and city and town halls, as well as banks, department stores, train stations, office buildings, schools, and hotels.

Examples of the range of building styles using Tyndall Stone, Saskatoon. A. Land Titles Building (1910). Neo-classical and neo-Romanesque. B. Eaton’s Building (1928). Neo-Renaissance style. C. Spinks Addition to Chemistry Building, University of Saskatchewan (2003). Châteauesque style. D. Health Sciences Building (2014). Collegiate Gothic style. E. Bank of Montreal building (1955). Modernist style (also Figure 21E). F. Use of split face, sawn and rustic finishes on exterior wall, in random (lower) and coursed ashlar (upper). Irene and Leslie Dubé Centre for Mental Health, Saskatoon (2010).

Heritage Status

In October 2022, Tyndall Stone was designated a Global Heritage Stone Resource by the International Union of the Geological Sciences Subcommission on Heritage Stones. This was ratified and as of late 2022, Tyndall Stone is an IUGS Heritage Stone, Canada’s first.

Publication: Heritage Stone 9. Tyndall Stone, Canada’s First Global Heritage Stone Resource: Geology, Paleontology, Ichnology and Architecture

Brian R. Pratt* and Graham A. Young**

*Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
**Manitoba Museum, 190 Rupert Avenue, Winnipeg, Manitoba, R3B 0N2, Canada