The ZO ČSS Býčí skála (ZO CSS Byci skala, literally translated as a Fundamental organization of the Czech Speleological Society, Number 6-01, Bull Rock) is an amateur caving group, one of sixty five such organizations that form the Society. In the National Speleological Society, NSS (USA), such groups are called “grottos”.
The group operates primarily in the central (middle) part of the Moravian Karst, namely in the Křtinské-Josefovské údolí (Krtiny-Josefov Valley). The Bull Rock Cave and the Barová (Bar) Cave are the principal localities. These caves form a part of the cave system of the Jedovnický potok (Jedovnice Creek). A large part of the system represents the creek’s underground stream bed. The creek begins its approximately 15 km long subterranean course in the ca. 4 km long ponor cave called the Rudické propadání (Rudicke propadani Cave, Rudice Swallet). The entire Rudicke propadani – Bull Rock – Bar cave system is situated up to 220 m beneath the Rudická plošina (Rudice Plateau).
The post-WWII period of cave exploration in the Moravian Karst, including the Krtiny-Josefov Valley and the Bull Rock Cave, was initiated by the Speleologický klub Brno (Speleological Club of Brno). The club was established in 1945 as an umbrella organization for all Moravian caving groups. In addition to regular members, the club included also so-called collective members – that is, caving groups organized mostly at works clubs (ZK) of the Revolutionary Trade-Union Movement (ROH) of major factories.
One of these members was the Speleological Group (SK) at the Adamov Machinery Works in Adamov (Speleologický kroužek ZK ROH Adamovských strojíren, Adamov). Established in 1954, the group focused on the exploration of the Bull Rock Cave. From 1954-1976, the cavers achieved several minor discoveries; in 1973, they also began to blast an adit in the roof of the Přítokový sifon (Influx Siphon), the terminal point of the cave.
On December 12th, 1978, the Czech Speleological Society (CSS) was formed. In 1981, the Speleological Group Adamov joined the society as the ZO CSS 6-01 Bull Rock.
Between 1982-1985, the Bull Rock cavers with the assistance of cave divers gradually discovered the entire underground stream of the Jedovnice Creek between the Bull Rock Cave and the Rudicke propadani Cave. Later on, in the 1990s, they physically passed through the entire system, from the Rudicke propadani Cave via the Bull Rock and Bar caves into the karst springs of the Jedovnice Creek in the Krtiny-Josefov Valley. The Jedovnice Creek cave system now stands as the second longest and best known cave system in the Moravian Karst and the entire Czech Republic.
Presently, the Bull Rock cavers concentrate on the resurgence area of the Jedovnice Creek, namely on karst conduits between the Bull Rock and Bar caves. Substantial progress is achieved almost every week, and not only in meters of newly discovered passages. A block of Pleistocene sediments in the Bar Cave has yielded a treasure of bone remnants of Pleistocene mammals including a well-preserved skull of a cave lion(ess) Panthera spelaea, and one of a cave bear, Ursus ex gr. spelaeus.
The progress and results of the group’s speleological activities are continuously reported on the group’s webpage, www.byciskala.cz (in Czech) as well as in speleological journals and bulletins.