Okay, last question...  In my simplistic model of the Earth, you
have the crust, the mantle and the core. Does anything live in
the core or at the core-mantle interface, and if not, what is
the first level/distance from sea level downwards that you start
seeing anything living or even getting close to being considered
living?   "Hope is a duty from which palaeontologists are
exempt." David Quammen