The rocks prevailing in the territory of the National Park are mainly of alpine age, limestone, marble and shale. There are three basic rock zones namely, the inferior one, which is called Plattenkalk and appears at Cavo Sidero in the form of marble plates, the intermediate, comprising dark red phyllite and shale, called Phyllites-quartzites, and the superior, made up of limestone, dolomite, flysch, sandstone, clay and conglomerate rocks and called Tripolitsa. In the mountain zone and above other rock layers there are erosion residues in the Magassa rock, comprising mainly white limestone. Over a more limited area, mainly in the northern part, there are more recent post-alpine rocks, the Miocene, Pleiocen and Pleistocene.