During the Cretaceous period (140-65 million years ago) a massive undersea landslide caught shoals containing thousands of marine bony fish such as Asteracanthus and Rhacolepis and buried them so quickly that they did not have time to decompose. 65 million years later, elongated limestone nodules that have eroded out from the rock often, when split, reveal perfect fish fossils complete with scales.
The older Permian strata (280 million years ago) of north east Brazil contain specimens of the freshwater reptile Mesosaurus. The only other place in the world where remains of these animals are found is South Africa. This fact is used as evidence for the principle of "continental drift".