Zlatý kůň National Nature Monument

One of the richest palaeontological sites in the world for finds from the Devonian period can be found at Zlatý kůň – The Golden Horse Hill. The Koněpruské jeskyně Caves, which are the longest cave system in Bohemia, can be found inside the hill.
 
Zlatý kůň NNM lies in the parish of Koněprusy in the Český kras – Bohemian Karst PLA and in the Středočeský kraj – Central Bohemian Region. The monument was declared in 1972 on an area of 371ha at elevations of 395-475 metres above sea level.
 
Zlatý kůň is one of the richest palaeontological sites from the Lower Devonian period in the world and more than 500 animal species have been recorded here. To the south of Koněprusy the Devonian layers form an extensive flat syncline, the core of which contain the youngest layers lie in the Zlatý kůň area. The northern edge of this syncline is of tectonic origin and runs along the Očkov reverse slip-fault, where older Lower Devonian and Silurian limestones were thrust from the north to lay on top of the firm Koněprusy Massif and the overlaying limestones.
 
Positions of Koněprusy limestones and the overlying Suchomasty limestone are exposed in the Houbův lom Quarry. Koněprusy limestone was formed in a tropical sea around 400 million years ago, and is characterized by its bleached white appearance and massive structure without apparent layering. At Zlatý kůň this limestone forms a typical reef, in which we can recognize the two main genetic types of limestone – biogenic and biodetritic. Biogenic limestone was formed by active reef-building activity of static organisms especially calcareous algae seaweeds, stromatopores, sea-lilies, corals etc. These limestones represent the core of the reef. Biogenic limestones only reach into the Houbův lom Quarry in a finger-like manner as the centre of the reef lay further to the north, where it is very clearly exposed in the eastern wall of the Císařský lom Quarry at Zlatý kůň Hill. Biodetritic limestone is built of grit (detritus) which was broken away from the reef by wave action, and also of collections of the remains of animals which found their most suitable conditions on the slopes around the reef and died there. These were predominantly brachiopods, false corals, corals, gastropods etc. These limestones filled in the gaps in the reef and formed massive banks around the firm core of the reef. The total volume of this type is far greater than, the volume of “core” limestone. These limestone types with an abundance of fossils can be seen at the Houbův lom Quarry on Zlatý kůň Hill. The Koněprusy limestone is extremely rich in fossils with representatives of most of the animal groups which lived at that time. The most abundant fossils are the sea-lilies, brachiopods (around 100 species recorded), clams, molluscs, trilobites (more than 50 species recorded), false corals, corals, stromatopores etc. The fauna content of the Koněprusy limestone outside of the Koněprusy area is relatively poor.
 
The Koněprusy Caves on Zlatý kůň Hill near Koněprusy are the largest cave system in Bohemia. The cave system is formed at three levels at depths of over 70 metres and a total length of around 2 kilometres. The caves are built in Devonian limestones and contain unique dripstone decorations (stalactites and stalagmites). The oldest type of dripstones are the so-called “Koněprusy Roses” in the shape of sinter balls which were formed by the layering of calcite and chalcedony. An abundance of skeletal remains of fossilized animals and several bones of humanoids of the Homo sapiens sapiens type have been discovered in the cave deposits in the Koněprusy Caves. Another unique find is the Medieval money-forging workshop in the upper level of the Koněprusy Caves. In the 1560s and 1570s money forgers made copies of the official silver coins (called “peníz”) here. The Koněprusy caves were rediscovered in 1950 and opened to the public in 1959. The caves are of exceptional geological, palaeontological, archaeological and historical significance.
 
A complete succession of xerophilous and thermophilous communities grow on the territory of the monument. These plant communities range from pioneer vegetation in rocky crevices, through species-rich rocky vegetation with the fescue Festuca pallens and the dominant, yellow-flowering sand cinquefoil (Potentilla arenaria) and the Bohemian small pasque flower (Pulsatilla pratensis subsp. bohemica), narrow-leaved fescue grasslands up to broad-leaved brome grasslands on deeper soils. Sheep and goat grazing has been re-introduced to help maintain the species diversity on these former pasturelands. A whole range of very rare thermophilous butterflies, including the critically endangered hermit butterfly (Chazara briseis), are bound to the extreme conditions in the former quarry below the entrance to the caves.
 
The Koněprusy Caves are also an important hibernating site for bats. Zlatý kůň NNM is a part of the proposed Zlatý kůň Site of Community Importance together with the Kobyla Nature Reserve.