NT1662 : Cut benchmark, Bavelaw.NT1662 : Cut benchmark, Bavelaw. This type of bench mark was used where there were no suitable vertical surfaces. A ballbearing carried by the surveyor would be placed in the small pit above the arrow . The surveying rod was then rested on this and so could be rotated easily to any position. Surveyors carried a pocketful of suitable ballbearings as these were frequently lost. Maybe worth having a look in the area around such marks just in case!