Seeing how no one has chimed in in a while...I'll just keep the story going. With Griswald's suggestion.
The party moves east into the chamber at the end of the small corridor. A thick mist surrounds you limiting vision to just 5 feet. A bit of careful exploration reveals rows of stone shelves on the walls, perhaps book shelves, but now they stand empty, and though you cannot see to comfirm it, you think they rise all the way to the ceiling. The floor is carpeted with rubble and stone.
A mysterious silhouette in the middle of the room, causes slight panic amonst the party intil it is revealed to be a harmless wooden lecturn.