March 2013 <i>GSA Today</i> cover (IMAGE) Geological Society of America Caption The monument at Klonk, Czech Republic, to the Silurian/Devonian boundary stratotype, which was defined in a section in the adjacent hillside. The people in the photograph formed part of a meeting of the International Commission on Stratigraphy in Prague in 2010. Credit GSA Today Usage Restrictions Credit GSA Today 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.