The core interval at the K.H5\6 and K.H5\8 wells in the west of Rutba province reveals a significant succession across the Late Cretaceous-Early Paleocene transition. The sampled interval encompasses a series of carbonates belong to Digma Formation of Latest Cretaceous age, which underlies the Akashat Formation of Danian age. Fifty-five species belong to thirty-five genera were recognized. Based on the distribution of these species, eight biozones were distinguished, three biozones are recorded from the K.H 5\6 studied section and two biozones are documented from the K.H 5\8 studied section which refers to Late Maastrichtian age of Digma Formation. Five biozones are recorded from Akashat Formation in the K.H 5\6 studied section and only one biozone is documented from the K.H 5\8 studied section which refers to Danian age. The depositional environment of the studied successions proposed it accumulated in the outer ramp environments.