Since the beginning of the XIXth century, the stone known as the Sillery Sandstone has been quarried intensively on the northern and southern banks of the fleuve Saint-Laurent, near Québec. On the northern bank, this stone was exploited in quarries in Sillery (Parks, 1914, p. 123-124, 126). It was used in several buildings such as in parts of the walls and gates of the old city, the walls of the Citadelle, a part of the base of the Parliament and of the former court house, the Notre-Dame-du-Chemin and St-Andrews churches and some parts of the Château Frontenac (Maurice 1955, p. 231-232; Maurice, 1973, p. 436). Jacob and Ledoux (2002, p. 4; 2003, p. 5-6) provided additional information on the characteristics of these sandstone and their uses.
It consists of fine- to very coarse-grained, greenish medium grey sandstone (wacke), which is very thickly bedded with red and green shale interbeds, and belongs to the Saint-Nicolas Formation. The bottom of the beds is sometimes conglomeratic.
Detailed fact sheet (available in French): CAR. DE SILLERY
PARKS, W.A., 1914. Report on the Building and Ornamental Stones of Canada, Volume III: Province of Québec, Ottawa, Department of Mines, Mines Branch, coll. Report (Canada. Mines Branch), n° 279, 304 p.