Cairn

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Cairn

A Cairn at Drumaldrace but possibly not the trig mark

Station marks of the old Principal Triangulation were usually buried, and only a few of the old primary and secondary stations were provided with some form of mark above ground level which normally consisted of a cairn, and then only when the station was on the top of a high mountain. [1]

A 'Cairn' is an uncommon type of mark in the Retriangulation. 16 instances, mainly in Scotland, are recorded in the OSGB36 list [2].

T:UK Station name Order Computed Block
TP7922 Beinn Dearg Cairn 3 1955 NC20
TP7916 Ben Griam More Cairn 2 1954 NC85
TP1926 Bogengarrie Cairn 3 1953 NK03
TP7925 Core Hill Cairn 3 1952 NK03
TP7929 Drumaldrace 3 1955 SE38
TP7920 Gars Bheinn Cairn 3 1959 NG24
TP7917 Great Bernera 4 1961 NC20
TP7551 Killegray 4 1957 NG24
TP7924 Mealfuarvonie 3 1955 NH40
TP7928 Prince Alberts Cairn 3 1956 NJ40
TP7630 Queensberry Cairn 3 1954 NX99
TP7927 Rosinish 4 1957 NG24
TP7921 Sgurr A Choire Ghlais 3 1955 NH54
TP7923 Suidhe Ghuirman Cairn 3 1955 NH54
TP7918 Suilven Cairn 3 1955 NC20
TP7919 The Stack (Stack Islands) 4 1957 NG24

Given the impermanence of cairns, with passers by liable to add or remove stones, perhaps rebuilding or even relocating them, then it is surprising that only Drumaldrace is recorded by the OS as 'destroyed'.

References

  1. The History of the Retriangulation of Great Britain 1935-1962, Section 2.06
  2. https://www.ordnancesurvey.co.uk/legacy/docs/gps/CompleteTrigArchive.zip