Sawiya Formation

The Sawiya Formation is a geologic formation in the Dominion of Ashura, dating to the late Dracian period. It covers a period between 154 and 149 million years ago, and preserves many terrestrial fossils of this time span. It is named after the Sawiya Oasis, located at the heart of the Ashuran Desert.

Most of the largest dinosaurs are known from the third stage in the formation, the Wadi-el-Kadut member; the younger Listëmirill Member contains a few fossils as well. The older two members, the Miandi and Lake Ereket members contain very few vertebrate fossils, though invertebrate remains and ichnofossils are known.

The paleoenvironment of the Sawiya Formation preserves a coastal floodplain that crept eastward. The oldest member, the Lake Ereket, preserves a series of what are most likely brackish water mud flats and fern-marshes (grasses did not exist at the time). The succeeding members are freshwater in origin, with the El Beniwara preserving a fully riverine environment as opposed to the more alluvial earlier zones. The land, as it expanded east, became a series of savannahs and open woodlands dominated by conifers, ginkgoes, cycads, and tree ferns comprising most of the taller flora. The El Beniwara member even bears cross-bedded aeolian sandstones, indicating that dune fields formed as the climate became wet and dry seasonally. Several unclassified dinosaur tracks are found all across the Sawiya Formation where it is exposed ground. Mammal burrows, as well as burrowed purportedly belonging to ornithopods, are also known.