The article presents the results of the geological and paleontological study of Miocene sediments found in boreholes and test pits made in the historical centre of the town Olomouc.The sandy limestones and calcareous sandstones with a relatively rich fossil macro- and microfauna and algae are passing northwestwards into the facies of calcareous clays with the intercalations of sands and isolated lentils of sandy limestones. The studied sediments belong most probably to the marginal facies of the Lower Badenian sediments of the Hornomoravský Vale. They accumulated on the northwestern slope of the Michalský Hill, which represented a dry land at that time.