Lower Miocene deposits of the Güneyce Formation formerly described as the Elmalı Formation of Lutetian-Burdigalian age are located near the villages of Gökçebağ (Burdur) and Yakaören (Isparta), ...(southwestern Turkey), Eastern Mediterranean, and overlie the pre-Neogene tectonostratigraphic units of the Isparta Angle. The purpose of this study is to discuss new biostratigraphic data calibrated to originally classified nannofossil records. Three Early Miocene nannofossil biozones, NN1 - Triquetrorhabdulus carinatus Zone, NN2 - Discoaster druggiiZone and NN3 - Sphenolithus belemnos Zone, were defined in clastic sediments of the Güneyce Formation. In addition, one Lutetian biozone, NP16 - Discoaster tanii nodifer Zone, was recognized in the remaining outcrops of the Isparta Formation unconformably underlying the Güneyce Formation. Nannofossil assemblages of shallow marine deposits in the Güneyce Formation contain high amounts of reworked (Palaeogene and Cretaceous) specimens. New biostratigraphic data and sedimentary features of the Güneyce Formation clastics indicate shallow marine deposition and the beginning of the transgression, spreading over an erosional surface on the ophiolitic melange and Cretaceous to Eocene marine successions rising to the west of the region.