At the base of Monticello Mountain, just below Thomas Jefferson's historic estate in Charlottesville, Va., sits a 90-meter-long greenstone wall. The Rivanna River runs on one side. On the other, earth has piled up to the wall's top. Built up from sediments washing down the mountain for centuries, this soil holds clues to history. But rather than bits of tools or pottery, the clues are chemical elements in the soil.
Note: To comment, Science News subscribing members must now establish a separate login relationship with Disqus. Click the Disqus icon below, enter your e-mail and click “forgot password” to reset your password. You may also log into Disqus using Facebook, Twitter or Google.