Rivet: Thirsk Bridge   

Mark on top of South battlement of Thirsk New Bridge ; 6.40 ft. above lower surface of keystone [1GL, Selby to Newcastle-upon-Tyne, Mark No. 83] - estimated location.

Location
Grid reference: SE 4315 8210.
Landranger 99: Northallerton & Ripon, Pateley Bridge & Leyburn.
Structure: Bridge.
Waypoint: RV0223.

Neighbouring Bench Marks

BOLT	Thirsk Bridge 20.00m to the east.
BM	Thirsk Bridge 22.36m to the northeast.
BM	Thirsk, Long Street 475.39m to the north.
BOLT	Thirsk, Church 487.54m to the northwest.
BOLT	Sowerby, St. Oswald's Church 741.69m to the south.

The nearest fundamental bench mark is Northallerton, 11.53km to the north.

First Primary Levelling, England & Wales (1840-60)
This bench mark was used during the First primary levelling, England & Wales, and was levelled with a height of 114.8770 feet [35.0145 metres] above mean sea level (Liverpool datum). It was included on the Selby to Newcastle-upon-Tyne levelling line. The surveyor's description was Mark on top of South battlement of Thirsk New Bridge ; 6.40 ft. above lower surface of keystone.