Survey Index

First primary levelling, England & Wales (1840-60). (163 of 185 lines)
First primary levelling, Scotland (1844-60). (36 of 104 lines)
Second geodetic levelling, England & Wales (1912-21). (114 lines)
Second geodetic levelling, England & Wales (1946-51). (14 lines)
Second geodetic levelling, Scotland (1936-52). (81 lines)
Third geodetic levelling, England & Wales (1950-68). (169 lines)
Third geodetic levelling, Scotland (1956-68). (90 lines)
Re-levelling of Greater London (1931-34). (21 lines)
Geodetic Levelling of Gibraltar (1961). (1 line)