In the Tertiary period a sea covered the present-day Vipava Valley. Hence, the edge of the Vipava Valley and the Vipava Hills are mostly built from tertiary sedimentary rocks such as flysch, various sandstones and limestones. The plateaus higher up display older rocks, but all are teeming with fossils – evidences of life from millions of years ago. Fossils are literally everywhere – in the valley and on the high plateaus. The finest examples of fossilized corals and shells – some of them even world-first discoveries – and other remarkable finds such as a fossilized shark tooth fragment are kept in the unique fossil collection compiled by Stanislav Bavčar, which is on display in the Museum of Ajdovščina.