273 COBISS: 1.01 ACTA CARSOLOGICA 28/2 17 273-291 LJUBLJANA 1999 Prejeto / received: 1. 10. 1999 1 Karst Research Institute ZRC SAZU, Titov trg 2, SI-6230 POSTOJNA, SLOVENIA 2 U.S. Geological Survey, 926 A National Center, Reston, VA, 20192, U.S.A. GEOLOGICAL CONTROLS IN THE DEVELOPMENT OF CAVES IN THE SOUTH-CENTRAL OZARKS OF MISSOURI, USA GEOLO[KE ZAKONITOSTI PRI RAZVOJU JAM V OSREDNJEM DELU JU@NIH OZARKOV, MISSOURI, ZDA STANKA [EBELA 1 & RANDALL C. ORNDORFF 2 & DAVID J. WEARY 2