Late Eocene age of Fayum mammal faunas

Re-evaluation of the stratigraphic boundaries of the non-marine Jebel Qatrani Formation (Fayum, Egypt) indicates that the entire formation should be dated to Late Eocene, Priabonian age. The Bartonian shallow-marine microfaunas in the immediately underlying formations are now assigned to the Middle Eocene, suggesting that the subsequent transition to coastal-plain deposition is best placed in the lower part of the Upper Eocene. The erosional surface at the top of the Jebel Qatrani correlates to the global hiatus in inner-shelf sequences which was initiated by eustatic decline at the end of the Eocene. Paleontology supports a late Eocene age for the Jebel Qatrani fauna, in that the fossil mammals show no signs of the radical modernization of African faunas that took place in the early to middle Oligocene.