Paleontology and geology

For much of the Jurassic, Saskatchewan was above sea level and exposed to erosion, except during the middle part of the period. During the Middle Jurassic, a shallow sea encroached over the province from the north. Stromatolites, brachiopods, bivalves, snails, and fish lived in these waters. Their fossils are found in limestones, and traces of other invertebrates are found in sandstones and shales. In some areas, the seas were so shallow that the water became extremely salty and the sea water evaporated, leaving behind deposits of different kinds of salt, like the economically important potash. All of these rocks are below the surface, and what we know of them comes from mines and drill cores.