Cut Mark: Simpson, Canal Bridge   

Old B.M. on battlement of canal bridge, junction of roads, Simpson [2GL] - estimated location.

Location
Grid reference: SP 8806 3631.
Landranger 152: Northampton & Milton Keynes, Buckingham & Daventry.
Structure: Bridge.
Waypoint: BM2561.

Neighbouring Bench Marks

BM	Simpson, Church 286.36m to the southeast.
BM	Bletchley, #176 Western Road 2.39km to the south.
BM	Bletchley, Milton Keynes Register Office 2.51km to the south.
BM	Bletchley, #14 Cambridge Street 2.54km to the south.
BM	Bletchley, The Bletchley Arms 2.57km to the south.

The nearest fundamental bench mark is Great Linford, 6.76km to the northwest.

Second Geodetic Levelling, England & Wales (1912-21)
This bench mark was used during the Second geodetic levelling, England & Wales, and was levelled with a height of 247.5020 feet [75.4386 metres] above mean sea level (Newlyn datum). It was included as a side level on the Great Linford to Hemel Hempstead levelling line. The surveyor's description was Old B.M. on battlement of canal bridge, junction of roads, Simpson.