This name was only recently given to the rocks of Abu Dhabi's western region which date to between 8 and 6 million years ago, thus falling into the Late Miocene epoch. The name comes from that of a region in western Abu Dhabi where the rocks of this date are most clearly exposed. The Baynunah Formation was created by an extinct river, known today as the Baynunah river, which may have been part of the system today represented by the Tigris and Euphrates rivers further north. The Baynunah river drained a large portion of what is today the Arabian desert, and consisted of a multitude of small channels, separated by banks of sand, several hundred metres wide. The river system had associated vegetation characterised by grasses, shurbs and trees, including palms and acacias. The diverse animal community which lived along the Baynunah river system is today represented by the over 900 fossils recovered there in recent years which represent the remains of some 43 species of vertebrates.