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A domed metal bolt set into masonry.
Also known as: Rivet benchmark, Domed benchmark bolt
A bolt benchmark is a brass or bronze bolt with a domed head set into horizontal masonry, the height taken at the top of the dome.
Marks a levelled height taken at the top of its domed head.
Contexts: Maps
Is set horizontally where the cut mark and flush bracket the catalogue already holds are set vertically, which is why the three types are found in different situations.
Contexts: Maps
Belongs to a network that is no longer maintained: published benchmark heights are archive information, and a mark may have moved with the structure it is fixed to.
Contexts: Maps
A small domed metal head set flush into a horizontal stone surface, often with a broad arrow cut beside it.