In the Mantle                                          -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      -      -

You are in the mantle.  The steamy air down here makes you cough as you
take a deep breath.  A flare of red is in the air, from the ash and molten
rock below.  The walls are covered with cracks, with red molten rock drying
between the cracks.  You touch the wall, and immediately bring your hand
back from suprise.  It is not too hot, but it is suprisingly warm.  Due to
gnome sorcerers the climate is life sustainable down here.  Climate control
makes the mantle a safe place to live, and in actuality, there is life in
the mantle.  To the north of here runs a mantle tunnel.