Tyndall Stone Limestone Tile, Canada Grey Limestone

Tyndall Stone is quarried at Garson, Manitoba, about thirty miles north-east of Winnipeg. Geologically, it is referred as the Upper Mottled Limestone of the Red River Formation of the Ordovician System. This is equivalent to the Trenton Formation of eastern Canada and the United States. However, the decorative mottling "like frost ferns on a window pane", characteristic in Tyndall Stone is unique among building limestone, and as a result, the stone is sometimes called the "tapestry stone". No satisfactory explanation can be given for the formation of the mottling which intersects through the mass like a sponge network giving structural reinforcement to the stone.
The fossil content of stone is used for assigning geological age, and throughout Tyndall Stone there are many interesting fossils of ancient marine life. The most common fossils found are the corals, particularly the sunflower corals. Also found are brachiopods, gastropods, and cephalopods. Fossils of snails and nautiloids can sometimes reach giant proportions. The trilobite, the three-lobed crab-like creature that is the dominant form of the lower paleozoic is only occasionally found.