September <i>GSA Today</i> Cover Image (IMAGE) Geological Society of America Caption Iron-rich silcrete mantles beveled quartzite in south-central South Africa. Deep valleys dissect the landscape and steep hillslopes separate the valley bottoms from the flat, gently sloping pediments. Credit Paul Bierman and <i>GSA Today</i>. Usage Restrictions Credit Paul Bierman and <i>GSA Today</i>. 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.