Dartmoor B.M.s

Dartmoor B.M.s

This Classification is Under Development.

I am slowly adding the Ordnance Survey Bench Marks or OSBMs. They are indicated as B.M. with a height on the old early 1900s Dartmoor Maps. It is surprising how many of these can still be found. However, as with all Dartefacts, an item shown in these maps may not exist! If I have visited a possible location I will still show a photo, but will add (Not Located) instead of a height in metres. Bench Marks were used to record height above 'Ordnance Datum'. If the exact height of one B.M. is known, the exact height of the next can be found by measuring the difference in heights, through a process of spirit levelling. OSBMs are often found on buildings or other semi-permanent features but on Dartmoor boulders, standing stones (!), field walls, gateposts etc. are often utilised. Although the main network is no longer updated the record is still in existence and the markers will remain until they are eventually destroyed by redevelopment or erosion. Some Bench Marks also have a 'bolt' inserted above them. I am starting to indicate which direct the B.M. 'faces' as this can aid discovery. In order to keep the B.M.s in an ascending height order I will have to add a '0' to the beginning of the height numbers i.e. 'B.M. 0648.5', although on the old maps it is written 'B.M. 648.5'. Thanks for that WordPress. Thanks.   A red Darticon or Mapicon means that the B.M. location has been visited but that it has not been located.   An orange Darticon or Mapicon means that the B.M. locations has not yet been visited.   A green Darticon or Mapicon means that the B.M. location has been visited and it has been located.

Dartmoor's Bench Marks have been categorised as follows:

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  • PUDC (Paignton Urban District Council) Boundary Stones, Venford Reservoir, Holne Moor PUDC (Paignton Urban District Council) Boundary Stones, Venford Reservoir, Holne Moor
  • Rock Basins Rock Basins
  • Refreshments, Facilities & Accommodation Refreshments, Facilities & Accommodation
  • Named Tors, Hills & Outcrops (for Baggers!) Named Tors, Hills & Outcrops (for Baggers!)
  • Millstones Millstones
  • Not Located Dartmoor B.M.s Not Located Dartmoor B.M.s
  • Not Yet Visited Dartmoor B.M.s Not Yet Visited Dartmoor B.M.s
  • WD (War Department) Stones WD (War Department) Stones
  • Tinners' Huts Tinners' Huts
  • Contour Rings Contour Rings
  • Cists Cists
  • Dartmoor B.M.s Dartmoor B.M.s
  • Dewey Hills Dewey Hills
  • Leats' Points of Interest Leats' Points of Interest
  • Found Dartmoor B.M.s Found Dartmoor B.M.s
  • Stone Circles Stone Circles
  • Standing Stones Standing Stones
  • Car Parks Car Parks
  • Prehistoric Sites Prehistoric Sites
  • Historic Sites Historic Sites
  • Stone Rows Stone Rows
  • PCWW 1917 Markers PCWW 1917 Markers
  • Crosses Crosses
  • Land Features Land Features
  • Water Features Water Features
  • Dartmoor 365 Map Dartmoor 365 Map
  • Trig Points (Trigs that can still be found!) Trig Points (Trigs that can still be found!)
  • PCWW 1919 Markers PCWW 1919 Markers
  • PCWW 1932 Markers PCWW 1932 Markers
  • Apple Crushers Apple Crushers
  • Hut Circles Hut Circles