the light moved in the boy 's hand , tracing first along a rock wall , then an ancient support with a trio of symbols carved into it - some long-dead chinese miner 's name , perhaps , or the name of his sweetheart , left far behind in the marsh - side huts of pc yang - and then to the floor , where it picked out a litter of bones : cracked skulls and ribcages that curved like ghastly cheshire cat grins .