Cephalopods and Stratigraphical Position of Cephalopod Bed of Shishtu Formation, Iran

This paper attempts to describe a cephalopod fauna from the "Cephalopod Beds" in the Shotori Range, Central Iran. The fauna contains 5 genera of nautiloid cephalopods and 12 genera of ammonoids. Among these, 7 ammonoid genera (Tornoceras, Cheiloceras, Maeneceras, Gonioclymenia, Cyrtoclymenia, Staffites, and Falcitornoceras) and 5 nautiloid genera (Ormoceras, Mooreoceras, Sycoceras, Michelinoceras, and Macroloxoceras) are reported for the first time from Iran.Ammonoid faunas indicate a Middle(?)/Late Frasnian to Late Famennian age for the "Cephalopod Beds", confirmed by conodont (Ashouri, 1990, 1995 & 1997) and brachiopod (Rastkar, 1996) studies.Microfacies analysis of the sections indicates that sedimentation occurred in a mostly shallow and high energy sedimentary environment.The distribution of goniatite fauna in eastern as well as northern Iran suggests similar paleobiological condition and a marine connection of the two regions during the Famennian stage. A paleogeographical map of the Late Devonian and comparison of the goniatite fauna of the study area with Alborz, Kazakhstan, China, North Africa and Europe indicate that these areas were in low latitudes during this time.