General:
     Biostratigraphy studies of coal beds in shemshak group show that the oldest coal layers belong to nurian stage, Howere upper most coal layers are related to Bajocian stage.
Generally speaking these sediments include of shale and sandstone and usually that are found in such as I lute, Kaolinite, Quartz, Epidote, Cholorite, Biotite minerals.
Morover the sandstane of these sediments are often Arkose type and to formed of Quartz, plagioclase, Albite, Moscovite, Amphibole and Zircon Minerals. The latest Geologcal researches show that these terigenous Sediments are in interral time of two old and middle Kimmerian phases