Charlie took the torch and set the candle down nearby, as he struggled in deep thought. Why on earth... 

"They could be coordinates of some kind? North, south, east, west. Check the bindings of book? There may be a key of some kind." 

He sighed, and turned to the group. " The stairs are blown so I assume once we go down we will need another way back..." 

Charlie peered back once more at the book trying to remember a pattern. One thing broke any attempt he thought of. "Why don't the deceased have a code?"