Paleontology and geology

While northern Saskatchewan remained above sea level, the southern part of the province was covered by a warm, shallow sea throughout the Ordovician. In the Early Ordovician, sandstones and shales were deposited as sediments continued to erode from the highlands nearby. Over time, solitary and colonial corals began to establish reefs, which were home to a wide variety of invertebrates, including brachiopods, snails, crinoids, bivalves, ostracods, nautiloids, and trilobites. Most of the rocks from this period are buried far below the surface under younger rocks, but a few exposures can be found in the eastern part of the province. The same rocks are quarried in Manitoba for use as building stone, and the limestone with its abundant fossils can be seen in many buildings, particularly in Regina.