Drill core site (IMAGE) Smithsonian Caption In seeking to understand the major evolutionary transition they had uncovered at Olorgesailie in 2018, Potts and his team had been frustrated by a large 180,000-year gap in the region's environmental record. To learn about how the region changed during that period, they had to look elsewhere. They arranged to have a Nairobi company drill in the nearby Koora basin, extracting sediment from as deep into the earth as they could. The drill site, about 15 miles from the archaeological dig sites, was a flat, grassy plain, and the team had no clear idea what was beneath its surface. With the involvement and support from the National Museums of Kenya and the local Oldonyo Nyokie community, a 139-meter core was removed from the earth. That cylinder of earth, just four centimeters in diameter, turned out to represent 1 million years of environmental history. Credit Human Origins Program, Smithsonian. Usage Restrictions News-media use of these photos in relation to this study is permitted with attribution. 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.