Abstract: The investigated area is located at the Elmadağ region (east of Ankara). The aim of this investigation is to establish the problematic age of the Elmadağ formation. This formation is composed offlysch - like sediments and limestone blocks of Carboniferous - Permian - Triassic age which were transportedby gravity - tectonics in the flysch - like sediments. Elmadağ formation shows a single - type flysch - like lithology (only clastic rocks), which, by means of sedimentologic features, can be subdivided in three members. Thesethree members are named from bottom to top as Arabıntaş member, Çakıllıdere member and Devecioğlu member,respectively. Elmadağ formation interfingers with Döşemedere formation which consists of basalt and spilitic basalt.The Irmak formation, an ophiolitic complex, overthrusts on the Elmadağ formation. According to our findings,the minimum age of the overthrusting of Irmak formation on the Elmadağ formation, can be given as UppermostCretaceous.The author, has identified the Werfenian - Hettangian age by the determination of biota and the microfaciesin the limestone pebbles of the fluxoturbiditic conglomerate bodies found within the Elmadağ formation. Accordingly, the age of Elmadağ formation should be Lower Jurassic (Lias) younger.