The Kůlna cave near Sloup is the largest cave in Devonian limestones of the Moravian Karst with favourable conditions for prehistoric settlement. In 1961-1976, the Quaternary filling of the cave was investigated by K. Valoch who distinguished 14 layers. They originated during Holocene, Würm Glaciation, the Riss - Würm Interglacial and the end of the Riss Glaciation. We studied petrographic composition including heavy minerals assemblages from the layers 7a, 7b and 7d, 8a corresponding to Lower Würm stadials and the layer 7c originated during the Lower Würm interstadial (Valoch 1988). According to their granularity, they represent silts in places with substantial content of limestone debris up to 30 cm in diameter (layer 7a). The assemblage of heavy minerals (60 - 75 % of hornblende, 1.5 - 10 % of epidote, 4.7 - 16.5 % of garnet, than zircone, rutile, turmaline and apatite) reflects the proximity of source areas. As the prevalent source of hornblende, epidote, zircon, routile, tourmaline and magnetite we suppose hornblende - biotite granodiorite of the Brno massif situated about 1.5 km to west. The Culm greywackes of the Protivanov Formation (in our opinion the main source of garnet) are only few hundreds metres to the north and moreover the Sloup valley (NW of the cave) is filled by roughly 60 m of fluvial sediments coming from the Culm area.