The transition from the Jurassic to the Cretaceous in the Persian Gulf area

For instance, it is an almost general practice to conventionally set the JK boundary at the top of the Hith or Gotnia anhydrites where these units can be identified. However, that proved to be wrong: Powers et al. (1966) first reported the large foraminifer “Iberina lusitanica Egger”, a Tithonian - lowermost Berriasian marker, within the shallow-water Sulaiy limestones that overly the Hith anhydrites, and first unit of the Thamama Group in Saudi Arabia. Similarly, Granier (2000) reported it as Anchispirocyclina lusitanica (Egger) , together with the dasyclad alga Campbelliella striata (Carozzi), an upper Kimmeridgian - Tithonian marker, from the shallow-water Habshan limestones that overly the Hith anhydrites, and first unit of the Thamama Group in Abu Dhabi.