A Damp Tunnel                                          -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      S      -

Like many of the other caverns in this section of the mountain, the
tunnel you are walking through has a great deal of vegetation growing in it.
The thick carpet of moss on the floor is soggy, and you can tell that water
is leaking into the tunnel from cracks in the wall.  Perhaps the melting
snow from the slopes outside has found its way in, allowing all the plants
here to grow.