The Neyriz, Surmeh and Hith Formations outcrop in the Persian Gulf area. Assemblages of benthic foraminifera andgreen algae were studied in 789 meters from these formations in theonshore middle part of the Persian Gulf, South of Iran. These forma-tions consist of grey shales, dolomite, limestone and anhydrite. The Neyriz and Hith formations are barren of fossils and the age of NeyrizFormation is Early Jurassic and the age of Hith Formation is Late Jurassic (Tithonian) based on stratigraphy. In the Surmeh Formation 18genera and 17 species of benthic foraminifera, 5 genera and 3 species of algae, one genus of bivalve and one genus of crinoid have beendetermined. Five biozones are defined based on the microfossil distribution, and consist of theLithiotisRange zone,PfenderinaRangezone,Trocholina palastinensis-TrocholinaAssemblage zone,Kurnubia jurassicaInterval zone and theClypeina jurassicazone. Diag-nostic larger benthic foraminifera indicate a Toarcian to Tithonian age for the Surmeh Formation in this part of the Persian Gulf Basin.

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