Rudists of the Tarbur Formation, in 7 km southwest of Semirum and 10 km north of Khorramabad, have been studied. Paleontological studies indicate that the age of the Tarbur Formation in both sections is Masstrichtian, and has a rich macrofossil fauna of rudist. The important types of rudist include Radiolites, Hippurites and Caprinidae. The assemblage shows a close similarity with those reported from south Turkey, Mediterranean, Saudi Arabia and Oman.