A little south of Medicine Hat, Alberta is Red Rock Coulee. The most striking feature of Red Rock
Coulee is the large, rounded sandstone concretions that can measure up to 2.5 meters across. It is
believed that the boulders were formed as calcite and iron oxide collected around a "nucelus" such as
a shell or bone. Layer upon layer of mineral was deposited over a long time to produce the boulders.