Biostratigraphy of the Ruteh Formation at Harijan section (Central Alborz) northern Iran using foraminifera and conodont

In order to study the fossil contents of the Ruteh Formation for biostratigraphical purposes, the 200 meters thick section was sampled at Harijan section, Central Alborz. The sequence is mainly made up of limestone and shale's. The lower contact of the formation with Dorud Formation is disconform while the upper contact with under learing Dorud Formation is disconformable with overling Nesen Formation is as well as disconformable. Fifty four species belonging to 27 genera (foraminifera and conodonts) were identified and three biozones were differentiated. These are formation: 1- _Schubertella giraudi_- _Codonofusiella distincta_ Assemblage Zone, 2- _Cribrigenerina sumatruna_- _Langella ocarina_ Assemblage Zone, 3- _Sweetognathus whitei_ Biozone. Based on, these an age of Yackhtaschian - Murghabian is quoted to the formation