of the Tamlelt whose northern edge is occupied by its higher peaks, such Jbel Ayachi at . The altitude falls towards the east where the mountains join the pre-Saharan zone. This massif became an internationally famous paleontological site after the discovery of the bones of a dinosaur called 'Atlasaurus', which populated Morocco 180 million years ago. This dinosaur is also named Tazoudasaurus, after the name of the village of Tazouda, where it was discovered. The creature, about long, is postulated to be an ancestor of the Sauropoda found in America. Until 140 million years ago, the African and American continents were connected. Geology The Atlas Mountains define an ENE-WSW trending intracontinental belt, resulting from the tectonic inversion of the Late Triassic to Middle Jurassic rift basin during the Cenozoic convergence between the African and Eurasian Plates. The Moroccan Atlas is formed by the ENE-WSW striking High Atlas and the NE-SW trending Middle Atlas. The former is divided into three segments named western, central, and eastern High Atlas. The western High Atlas was part of the Atlantic Jurassic passive margin and is separated from the central and eastern High Atlas by the Paleozoic Massif, an area of pre-Mesozoic basement exposures located south of Marrakesh. The central and eastern High Atlas basin developed as a multiphase rift system opened toward the east by two major rift episodes occurring during Middle-Late Triassic and Early Jurassic (late Sinemurian and Pliensbachian. At present, the central High Atlas is characterized by a folded domain that is dominated by NE-SW striking structural highs or ridges separating elongated and wide synclines filled by Early and Middle Jurassic sediments. Subordinate NW-SE trending structural highs bounding equal-trend synclines are also present. Cretaceous and later syntectonic Tertiary units are also locally present (e.g., Miocene-Pliocene La Cathédrale conglomerates and sandstones). Triassic-Jurassic During the Triassic, the central High Atlas extensional basin was characterized by the synrift deposition of red beds and localized evaporites capped by extensive basaltic lava flows. Following the Triassic red bed deposition, marine conditions prevailed during the Early and Middle Jurassic resulting in the development of carbonate and mixed depositional systems. The Jurassic Atlas basin was open to the east (western Tethys realm) with Paleozoic provenance areas located toward the west and south. Liassic sedimentary systems evolved from extensive peritidal shallow water carbonate platforms (Hettangian-lower Sinemurian) that progressively backstepped toward the basin margins, to more localized platform development flanking the