On the morning of Thursday, July 23rd, rangers learned of the discovery of unexploded military ordnance near the heavily-visited Fossil Exhibit Activity and Trail area along Norbeck table. The ordnance â a belt of unexploded 20 mm shells â was found by park paleontologists who were conducting surveys in the rugged formations east of the visitor use area. A military EOD team from Ellsworth AFB was contacted and came to the park. Team members inspected the shells, determined that they were too unstable to move, and exploded them on site. The detonation was heard at the park visitor center more than three miles away. Itâs believed that the rounds were dropped by a military aircraft during training exercises in the 1940âs.