This is a levelling benchmark placed and used by Ordnance Survey. Its location is SK 2305 8759 at Moscar on the footpath from the A57 towards Stanage. The mark was made in 1961, is of the third order of surveying and is 600mm above ground level. Its datum is Newlyn. Originally the mark and boulder were on the west of the footpath but time and boots have now placed it east of the path.
There are some 500,000 benchmarks on the UK mainland, most no longer in use. They identify the height at a given point. The base line is the tidal measuring station at Newlyn in Cornwall, that is the point where all height measurements are taken from, including the 190 Fundamental Benchmarks which were the first order and therefore the most accurate, set in chambers deep underground on bedrock , these benchmarks are still in use today by the Global Positioning System for calculating the accuracy of the height calculation.