On the Cavern Floor                                    -      N      - 
(-------------------------------------------------)     W <---(M)---> E
                                                        -      -      -

As you traverse the cavern floor, you find that the gloom is catching, as
a depressing pall fills your soul.  To your north, the skeletal bridge rises
from the mists, like some ghastly beast from the very shadows of your soul. 
Beyond the bridge and mists the gloom seems to lift as light begins to seep
into the cavern from some unknown source in that direction.