الملخص

Twenty-one surface samples from Avanah Formation dating to Middle Eocene cropping out in Dohuk area, northern Iraq, were studied for their nannofossils with light microscope .The study shows that the formation contains a rich and varied assemblage of nannofossils with a significant development of special forms such as Discoasters and Coccolithes . These forms are useful as stratigraphic indicators in Paleogene sediments and as paleoecological indicators of the studied area. One of these samples had being studied by Scanning Electron Microscope to show some of the diagnostic features of the studied species. The study resulted in the recognition of (12) species belong to (10) genera of calcareous nannofossils.