ABSTRACT: Aladaf regton, iiroıınd Kii^iiksıı and IMidëken yayla, TJppeırmost Permian, Poııninıi-TriasHİc. transition, and Lowermost Triasslo are repreBented by marine Umestone sequences, la order to clarify the oharaoterlstio iof rermian-Triïissio trasiNitioıı, au Investigatton to define formnlnUera population concmwnt range zones has been carried out In thèse sequences. In the sequence where no stratigraphie hiatus could be found, the par!» corresponding to the zones exhtMt different facie». The lower part consisting of htoclastic, dark-brown limestones at Uppermost Permian age contains foraminifera i»f Dagmarlta chanakohfensta Keitlinger, dlolnvalvulina voııdersclııııitü Ileichel, Staffellai »p., FiM`hyphïoï» »p., Faradagmorlta sp,, Kamurana sp, and atgael fragments like (.Syinnoco dlum sp,t PennocalonluB sp, and Mi`/v.in, sp. This part Is defined as the first foraminifera population concurrent range zone. The seeoiMl part wliioolitic limestones of Uppermost Pt^rmiiin-l.second foramtaüıfera population eianourrent range «one, Dagmarita sp,, Paehypholfe sp, anfl * Oyelogyra sp. have been found In the core» of o»Utes and Cyologyra ? mahajeri Ho to ftm cement. The part above consistingof yenow-Tgray limestones mt Lowermost Permian age contains Cyologyra Î mahajer^, Üeetocornusplra Icalhori Bröniimiann, Zaninetti and Bozorgnla, Ammodtecus parapriscus. Ho, Glomosplrella sp., Barlandla sp, and Harlandinita sp, an it is defined as the third foraminifera population concurrent range zone. The upper. nvMt part consisting- of light-gray limestones which are laminated In its lower sections and thick bedded 1B ite upper sections contains Meandosplra pusllle (Ho), Glonu»plreUa sp. Thus, it is defined em the fourth foriiminiferu p()pulatiAs a result, It M shown that around KÜettksu and I>isTriassl« transition te gradatioaal by mean» of the defined foraminifera population concurrent range zone».