10. Fossils in Limestone Outcrops

The steep rocky slope below the municipality of Kosoř is notable for geological profiles and fossil sites in numerous abandoned quarries. The site got its name (Černé rokle, Black Ravines) from black-grey Radotín limestones. The upper parts of the slopes are covered by thermophilous grasslands and the rock outcrops by communities of rock steppes. Thank you for your helpful, nature-friendly behaviour

Limestone Isn’t Always White

The steep rocky slope below the village of Kosoř is notable for its geological profiles and numerous fossil sites found in abandoned quarries. The locality takes its name from the black‑grey Radotín limestones, formed on the floor of a Palaeozoic sea around 410 million years ago, during the Devonian period.

Life of the Past – and Today

These limestones contain abundant evidence of ancient marine life – fossils of bivalves, gastropods, trilobites, cephalopods, and many other organisms. The upper parts of the slopes host warm‑loving grasslands, while the rocky outcrops support rock‑steppe communities.

Did you know…

… limestone from this site was once used to make Prague’s sidewalk mosaics?

Pictures from the information panel:

• Spiniscutellum umbelliferum is a characteristic trilobite of the Radotín limestones. (Photo: Š. Rak)
• Italian bellflower attracts insects with its nectar. (Photo: T. Tichý)
• Geological profile showing the boundary between the Lochkov and Prague formations. (Photo: V. Ložek)
• Showy St. John’s wort grows outside the Český kras region only in the České středohoří. (Photo: J. Mottl)
• Long‑tailed blue is a summer species of sunny habitats. (Photo: P. Heřman)
• Fringed gentian flowers from August to October on the floors of abandoned quarries. (Photo: J. Mottl)
• “Sudy” rock forms are geomorphological features shaped from Devonian limestone. (Photo: J. Mottl)

This area is managed by the Nature Conservation Agency of the Czech Republic, Administration of the Bohemian Karst  Protected Landscape Area.

We protect nature here for you.

Thank you for helping us.

The boundary of the protected site is marked by two horizontal red stripes on trees or posts. The upper stripe encircles the whole trunk; the lower stripe appears only on the side outside the protected monument.

To safeguard the fossils, which are valuable evidence of palaeontological and geological history, collecting fossil material is permitted only when done carefully in loose scree.

Thank you for respecting this rule.