Cretaceous–Paleogene extinction event Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction, was a sudden mass extinction of some three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the exception of some ectothermic species such as the leatherback sea turtle and crocodiles, no tetrapods weighing more than survived. It marked the end of the Cretaceous period and with it, the entire Mesozoic Era, opening the Cenozoic Era that continues today. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can
Eldon George as a sparrow or robin. In 1986, a scientific team that included Paul Olsen, discovered hundreds of thousands of fossils at Wasson Bluff, one of the biggest troves ever found. Fossil discoveries on the Fundy shoreline are especially significant because they date from 200 million years ago, the boundary between the Triassic and Jurassic geological periods, when about half of the Earth's living creatures suddenly became extinct giving rise to dinosaurs and the mammals that eventually succeeded them. Many of the fossils that date from that time remain hidden, buried under North American forests, farmland or cities. But, the Fundy