Poverty Point Excavation (IMAGE) Washington University in St. Louis Caption An excavation before sampling. Note the color changes between layers. The darker layers have carbon-rich deposits made by humans, such as midden or garbage that was scraped up and dumped to form the ridge structure during construction. There is little organic garbage in the upper third section. Credit T.R. Kidder Usage Restrictions None License Original 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.