Maybe a rock? Rock nearer to the surface is younger than that which is underneath. Same goes for dirt. If you dig deep, deep into the ground, you may find yourself steeped in the middle of dirt that is millions of years old. On the other hand, if you are handling topsoil, that's only a few thousand years old. And, dirt presumably comes from rock, so I guess if you're as old as dirt, then at least you're younger than rock.
http://www.nytimes.com/2011/06/14/science/14qna.html?_r=1&ref=science
