Fossil neanderthals have also been reported to overlap with modern humans. Creationists should be aware, however, that evolutionary theory no longer predicts that an ancestral species will necessarily disappear when its descendant appears. The mother of mass extinctions. The largest mass extinction in the geologic record is at the top of the Permian. Marine fossils from Paleozoic rocks are predominantly immobile types, such as brachiopods, crinoids, and rugose corals.
Mesozoic rocks contain more mobile types, such as crabs, snails and fish.
The cause of this mass disappearance is not known, but may be related to extensive volcanism in Siberia, or to changes in sea level. There is no evidence for a large end-Permian extraterrestrial impact. Two features of this mass disappearance are of particular interest. First, the change in ecological types from largely immobile Paleozoic types to more mobile Mesozoic types may be an important signal of the processes responsible for catastrophic deposition of the geologic column. Second, the apparent relationships among flood basalts, sea-level changes and mass disappearances may suggest fruitful areas of investigation for catastrophists.