Abstract: Detailed geological mapping of the western side of Çankırı basin demonstrates that the base of the Neogenesuccession, the Kılçak formation, is found on both sides ofa tectonic sliver. These outcrops are correlated throughtheir lithological descriptions and fossil contents. This finding eliminates the recent tectono-sedimentary modelthat presents the Kılçak formation as a last product of an intercontinental convergence, developed in front ofthethrust sheets of the İzmir-Ankara suture zone. In contrast, our findings support the proposal that the Neogenesuccession in the western margin ofthe Çankırı basin is fragmented by the post Pliocene tectonic sliver, regardedas a neotectonic structure.