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A 'Hole' is an uncommon type of triangulation mark.

16 instances are recorded in the OSGB36 list [1]. Mark descriptions include "Punch hole in roof", "Drill hole in bolt", "Hole in tank rivet", "Hole in washer on roof" and "Hole in iron plate".

Some, but not all, holes are included in stations containing other types of triangulation mark. The station locations include Water tanks, Church towers and Colliery headgear.

12 of the marks are recorded as destroyed. The corresponding trig stations are:

Bricksbury Hill Water Tank,
Burradon Colliery Headgear,
Danes Hole Water Tank,
Heath End Colliery Headgear,
Hospital Water Tank North,
Long Sutton Water Tank,
Petters Tower,
Rainworth Water Tank,
South Water Tower,
Waltham Water Tank,
Witchford Water Tank,
Wraysbury Ballast Hopper

Of the remainder, 3 are deemed inaccessible and 1 possibly missing. These corresponding trig stations are:

Cargate No 2 Reservoir Hole,
Greenbank Church Tower Centre,
Sandal Castle,
Sandyhills High Flats HOLE

As yet, no holes have been photographed. In appearance holes are likely to resemble a punch mark.


  1. https://www.ordnancesurvey.co.uk/legacy/docs/gps/CompleteTrigArchive.zip