The presence of nummulites--?N. millecaput--and other foraminifera in the uppermost limestones of Mt. Olympus (Greece) indicates that the limestone series extends from the Triassic into the Eocene, probably Lutetian. Sandy-shaly flysch concordantly overlies these limestones. Since the limestones show effects of the orogenic movements which disturbed the internal zones of the Hellenides, the Olympus folding is attributed to the upper Eocene. It is concluded from this that Mount Olympus was emerged at the beginning of the Eocene and escaped the invasion of terrigenous material from adjacent regions.