Ordovician Limestone is a type of sedimentary rock formed during the Ordovician Period, which lasted from about 485 to 444 million years ago. This limestone primarily consists of calcium carbonate, derived from the remains of marine organisms like corals and shellfish. It often contains fossils, providing valuable insights into ancient marine ecosystems. The formation of Ordovician Limestone typically occurs in shallow, warm seas where sediments accumulate over time. This rock is significant in geology and paleontology, as it helps scientists understand the Earth's history, including changes in climate and sea levels during the Ordovician Period.