An analysis of microfacies features and of larger benthic foraminiferal assemblages which include imperforate and perforate, was used to define microfacies types. The predominant microfacies are; 1) Rudist, orbitoidae wackestone packstone; 2) Rudist packstone; 3) Bioclast grainstone; 4) Orbitoidae, miliolids, bioclast wackestone packstone; 5) Dicyclina, miliolids, bioclast wackestone packstone; 6) Miliolids mudstone; 7) Peloidal, bioclast wackestone packstone; 8) Bioclast, ostracoda packstone grainstone. Three major depositional environments are identified in the Tarbur Formation on the basis of grain types, physical and biogenic sedimentary structures and vertical facies relationships. These include shallow subtidal (shelf lagoon), sand shoal and open marine. Tarbur Formation sediments were deposited on a ramp carbonate platform. Four depositional sequences were also recognized in the Tarbur Formation. TST sediments dominated by hyaline foraminifera and HST sediments dominated by various taxa of imperforate foraminifera. The assemblages of perforate and imperforate foraminifera and microfacies are used for interpretation of palacoenvironment features of the Tarbur Formation.