Twenty Samples of Shiranish Formation from the well (K-306), Kirkuk area, northern Iraq, are collected and studied on the basis of stratigraphic ranges of the recorded calcareous nannofossils. Eighty-nine species in the studied section reveals five biozones arranged from oldest to youngest as follows: 1.Quadrum trifidum Interval Biozone (CC22) Part 2.Tranolithus phacelosus Interval Biozone (CC23) 3.Rienhardtites lives Interval Biozone (CC24) 4. Arkhangelskilla cymbiformis Interval Biozone (CC25) 5. Nephrolithus frequens Rang Biozone (CC26) PartThese Biozones are correlated with other calcareous nannofossils biozones, from both local and regional sections, leading to conclude the age of Campanian-Maastrichtian.

Eight samples of Shiranish Formation were obtained from Balad well No. 8, (northern Baghdad) central Iraq. Details investigated carried out identify calcareous nannofossils, where identified sixteen species; eleven descried from other region and five left under open name because of lack of material or rare of samples, On the basis of stratigraphic distribution of the species, two biozones proposed these are : 2-Reinhardites levis Interval Biozone(CC24) 1-Tranolithus phacelosus Interval Biozone(CC23b)The proposed biozones correlated with others calcareous nannofossils biozones from regional schemes led to conclusion that the age of Shiranish Formation in studied section Early Maastrichtian.

Fifteen samples from the lower part of Shiranish Formation, Sinjar anticline, northwest Iraq, are investigated in order to identify calcareous nannofossils species of which twelve species are recorded as follow; one species of holococcoliths, seven are heterococcoliths and four are nannolith. On the basis of the above assemblages two biozones are proposed from oldest (at bottom) to youngest (at top):The above biozones are correlated with other calcareous nannofossils biozones from regional view led to conclude that the section is late Campanian in age.

A detailed systematic study of calcareous nannofossils was carried out for the Jaddala Formation in (Aj-10) well, Central Iraq. Seventy one species belong to twenty four genera of calcareous nannofossils were identified including sixty two of them were previously named and nine species were identified for the first time and they would not be given names until more information is obtained in the future to support this identification. It is a recorded of five biostratigraphic zone, which suggested the age of the Jaddala Formation to be of early to late Eocene. The recorded biozone includes the following: Reticulofenestra dictyoda (Deflandre in Deflandre & Fert, 1954) Stradner & Edwards, 1968 Partial Range Biozone (CNE 5); Discoaster sublodoensis Bramlette and Sullivan, 1961 Interval biozone (CNE 6-7); Nannotetrina cristata (Martini, 1958) Perch-Nielsen, 1971 Interval biozone (CNE 8); Nannotetrina alata (Martini in Martini & Stradner, 1960) Haq and Lohmann, 1976 Interval biozone (CNE 9); Chiasmolithus gigas Bramlette & Sullivan, 1961Range Biozone (CNE 10-11).

Seventy three species of calcareous nannofossils are recorded from the studied section of Tanjero Formation at Azmer anticline, Sulimaniya, Northern Iraq. The studied section reveals four  biozones arranged in an ascending order  from oldest to youngest as follows; Tranolithus phacelosus Interval Biozone (CC23) Part, Rienhardtites lives Interval  Biozone (CC24), Arkhangelskilla cymbiformis Interval Biozone (CC25), and Nephrolithus frequens Rang Biozone (CC26) Part. These biozones are correlated with other calcareous nannofossil biozones of both local and regional sections, leading to conclude a possible age of  Late Campanian- Maastrichtian.