The cave system of Beka-Ocizla is developed in the area of contact between Palaeocene limestone and Eocene flysch at 350 m a.s.l. in south-western Slovenia. The beds of limestone could generally be traced in the direction towards NW, the most distinct tectonic structures are in the Dinaric direction and transversely to the Dinaric direction. Three bigger streams and one smaller flow from the flysch on the contact with limestone, which sink into the limestone. The following caves are connected to the cave system: Ocizeljska jama, Bla¾ev spodmol, Maletova jama s slapom, Jama z naravnim mostom, Jurjeva jama v Lokah and Jama S-4 / Socerb, the entrances of four of those caves function as occasional ponors. The least close entrances are 500 m away from each other. The water in the system simultaneously flows on various levels and drains in the direction of Boljunec. The system of parallel fault planes with dip 220/50-80 is the most important for the development of the cave system, the general direction of the cave's passages and the flow of water in the system.