Introduction:In a clear summer day while standing on one of themountain tops of Linglungshan,~1 Chaoyuan,~2 Shantung,I saw severalmesas rising conspicuously at a distance of about thirty miles to thesoutheast.These topographical features remined me the possible occur- Introduction: In a clear summer day while standing on one of themountain tops of Linglungshan, ~ 1 Chaoyuan, ~ 2 Shantung, I saw severalmesas rising conspicuously at a distance of about thirty miles to the southeast.These topographical features remined me the possible occur-