Rapelling into Sinkhole (image) Geological Society of America Share Print E-Mail Caption Mike Mallner, a technical caver who accompanied Leila Donn on her field work, rappels down into the large sinkhole. The previously unidentified feature is 60 meters by 30 meters and 35 meters deep. Credit Leila Donn Usage Restrictions Credit Leila Donn Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.