A Reddish Bed Containing Fossil Sponges (IMAGE) U.S. National Science Foundation Caption Below a cliff, a reddish bed is one of many stromatolite bioherms containing fossil sponges. Credit Adam Maloof Usage Restrictions None 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.