Abstract: The Gürleyikdere formation consists mainly of limestones of algal biomicritey algal biosparite, bryozoans biosparite, biomicriteand boundstone character. Micritic matrix and spar it ic cement are dominant from place to place. Abundant benthic-planctonic foraminifer a, algae, bryozoa, nannoplancton, coral and brachiopoda fossils occasionally reflect shallow marine (litoral) and reefal conditions. Gürleyikdere formation Itad been deposited on the wave base and it has a reefal character according to its several properties.Three different fades zones have been determined in four different standard microfacies, characterizing deep shelf margin, platformmargin, shelf lagoon, reefal and reef front environments. Deeper locations of the deposilional area were situated in the E and S E part of the area at the Paleocene-Eocene period, while locally stable and deeper regions were determined at the W and SW part of the investigation area.