Cretaceous
The Cretaceousis a geologic period and system from circa 145.5 ± 4 to 65.5 ± 0.3 million years ago. In the geologic timescale, the Cretaceous follows on the Jurassic Period and is followed by the Paleogene Period of the Cenozoic Era. It is the youngest period of the Mesozoic Era, and at 80 million years long, the longest period of the Phanerozoic Eon. The end of the Cretaceous defines the boundary between the Mesozoic
Flowering plants appeared. The Cretaceous ended with one of the largest mass extinctions in Earth history, the K-T extinction, when many species, including non-avian dinosaurs, pterosaurs, and large marine reptiles, disappeared in HE. In DW, it was just as injurious, causing the extinction of all non-avian dinosaurs with the exception of some Leipsanosaurs, as well as significant portions of the other large reptilian fauna, such as the majority of the Ctenosauriscids and all Pterosaurs, as well as many less successful non-Triconodont mammals.
Flowering plants appeared. The Cretaceous ended with one of the largest mass extinctions in Earth history, the K-T extinction, when many species, including non-avian dinosaurs, pterosaurs, and large marine reptiles, disappeared in HE. In DW, it was just as injurious, causing the extinction of all non-avian dinosaurs with the exception of some Leipsanosaurs, as well as significant portions of the other large reptilian fauna, such as the majority of the Ctenosauriscids and all Pterosaurs, as well as many less successful non-Triconodont mammals.