Site of Limestone in South China (IMAGE) Stanford University Caption A distant view of the field area in the Nanpanjiang Basin in south China where limestone contained evidence of a slow recovery of marine animal populations after the mass extinction 250 million years ago. Credit Katja Meyer, Stanford University Usage Restrictions May not be altered or sold for profit. License Licensed content 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.