Brázda Abyss

It had been the deepest abyss not only of the Slovak Karst but of the previous Czechoslovakia for a long time. It is located on the Silická Plateau, 2,5 km north-westerly from Silica village. The depth is 181 m. This corrosion fissure abyss, with several vertical steps or horizons is formed in Mesozoic Middle Triassic pale Wetterstein limestones of the Silica Nappe. Several cave walls are decorated by remarkable peas formed flowstone protrusions. A side cascade passage 150 m long opens to the lower part of the abyss, which lead upwards into a dome with magnificent flowstone decoration.

6 bat species were determined in the Brázda Abyss. It is an important hibernation space for the Lesser Horseshoe Bat (Rhinolophus hipposideros). The troglophilic invertebrates are represented by tiny spider Porrhomma profundum, multipede Polydesmus denticulatus and crustacean Mesoniscus graniger, which is Carpathian endemic species. Troglophilic arachnid Gemmazetes cavatica is abundant on bat guano.

The deepest parts of the cave were surveyed by cavers from Brno in 1953. They resumed in surveys in 1963 – 1968 when discovered the most beautiful part of the abyss.