New investigations on the stratigraphy of the Khoshyeilagh Formation (Lower part)

The Type-Section of the Khoshyeilagh Formation in the eastern Alborz Mountain (Iran) was biostratigraphically re - investigated in its lower part. The lower fossiliferous horizons are proved by means of brachiopods to be of Lower Devonian (Upper Emsian age). A sequence of strato, void of Macrofossils is underlain by the fossiliferous Upper Emsian and covered by the proved lowest Upper Devonian, may be assumed to be wholly or partly Middle Devonian.
In the revised lower part of the Upper Devonian section, two horizons are distinguished by means of brachiopods (Lower and Middle to Upper Frasnian).