A very thick and lithologically rather unusual marine sedimentary succession is described from the Kuh-e-Shisui area, northwestern Lut Block (east-central Iran). It contains a low diversity ammonite fauna comprising the families Dactylioceratidae, Hildoceratidae, Graphoceratidae, Hammatoceratidae, and Sonniniidae, which are concetrated in several levels, indicating the Lower-Lower Middle Toarcian, Upper Toarcian, Aalenian, and Lower Bajocian. The ammonite fauna, consisting of 21 taxa, descibed for the first time from the Lut Block, corresponds to that of the Badamu Formation of the Kerman-Ravar region (southern Tabas Block, to the west of the Lut Block), but is far less diverse. An exception is the occurrence of Lower Toarcian Harpoceratinae and Hildoceratinae, which hitherto have not been recorded from east-central Iran. The ammonite fauna is closely related to that of northwestern Europe.