Abstract: Oil shales have been deposited from Precambrien to Tertiary in the geological history of the Earth, andthey are distributed in Europe, South America, Western United States, and in Turkey. Middle anatolia, Western Blacksea, Aegean and Marmara regions are important in respect to oil shales in Turkey. Volcanosedimentary lacustrine basins of Neogene age are the main geological environments in which oil shales were deposited in Turkey. Himmetoğluoil shale field have been selected as an example among the others. So, only this field have been investigated in detail.Himmetoğlu formation occurs in a graben, caused by reactivation of paleotectonic structures in the neotectonicregime. Lithostratigraphical features of this formation have been investigated in detail on core samples.Himmetoğlu formation has 4 different zones: Green clay and conglomerate, lignite bearing, banded bituminousmarl, laminated bituminous marl. Organic matters and pyroclastic sediments which were transported in different periodshave been deposited together in the basin.