Boundary Stones

Military boundary stones, not to be confused with Ordnance Survey datum points, are somewhat of an enigma. Historically they delineate boundaries of military sites, however their use is not consistent – some sites have them, others do not, and as for design, there are many different styles. Their use appears to extend as far back as the end of the 18th century, through the construction of early 19th century Napoleonic forts up until post-WW2 sites. They are present around sites that have no visible boundary fence, such as military training areas or ranges, in just as much frequency as sites that have large boundary walls into which the stones are either built or lie at the base of.

Ordnance Survey datum point, not a military stone

Marked with the broad arrow (or crows foot) this symbol was the mark of the Board of Ordnance and has been in use since 1699 on ‘stores of war’ belonging to the Board. In 1805 this mark was extended to all ordnance stores in use by ‘His Majesty’s Service.’ The only real variation to this was stones placed by the Admiralty, which are adorned with the ‘fouled anchor.’ The Board of Ordnance was disbanded in 1855 after which it became the War Department. However, some stones are marked with the letters BO and the broad arrow; which denotes the Boundary of the (Board of) Ordnance as opposed to Board of Ordnance.

Dating the Stones

Dating any stone marked with the arrow in isolation is inherently difficult as their construction and design varied depending on where, when and who was commissioning them. The implication that stones were placed at the time of construction or development is one assumption that has to be made when attempting to date stones. One good case study is the site at Fort Halstead.

Map of Fort Halstead including stone locations and numbers

Originally constructed as a London Mobilisation Centre  in the 1890’s, maps of the site (above) clearly show stones (WD BS) placed in sequential order (1 – 8) around the land purchased for the site. The site was subsequently sold in 1921 and fell into private ownership. At this stage the fort was no longer property of the War Department, so it makes sense that the stones denoting ownership were removed – which might explain why none of the original stones, as mapped, appear to be extant. However, another feasible explanation may be that as the site developed after its repurchase in the 1930’s and the boundary extended past the original 3 acres that old stones were removed or repurposed as the boundary was pushed out. As to when the siting or relocating of boundary stones occurred, I can find no evidence to state when. this would occur.

What does exist however, are three styles of stone (triple image below). Placed around what is now the external boundary of the site, far larger than the original fort and WW2 expansion are stones of style 2 below. These stones are renderedin a concrete with very crisp number (although if every number was sequential, there are a lot of stones missing) and WD markings (pre 1964, most likely from the late 1940’s expansion of the site). The placement of these stones is to the south and west, along the boundary that has not changed since WW2. I am led to believe there are some of this style of boundary stone inside the current site marking where the WW2 site boundary lay.

Style 1 below is the very first stone on the approach to the modern site from the public road. It appears to be solidconcrete, and sits outside the perimeter laid by style 2 stones. It is unclear if a number is also on the stone but below the surface of the present ground – the fact that this sits much lower may also be evidence it possibly predates the others (circa 1930’s). I am confident that this stone is WW2 and predates styles 2 and 3.

Style 3 is a simple MOD post most obviously lacking the crows foot of the previous stones (circa 1964+) and would have been added as the site expanded in the 1960’s. MOD stones are only present to the north of the site where the boundary was pushed out, while remainder of what is the original perimeter has concrete block stones throughout. The practice of recording BS stones on OS maps has now stopped – as to when the practice ceased, that is unclear.

Fort Halstead stone types. Style 1 is the first stone on the approach road to the site and most likely dates from the pre-WW2 repurchase of the site. Style 2 were probably introduced during the late 1940’s expansion. The MOD as it is today was formed in 1964, after which the series 3 posts must have been placed, but are much less elaborate than others found elsewhere.

Boundary stones could generally be placed into broad date categories:

  1. BO– 1597 until 1855. It is unclear when the use of boundary stones began.
  2. Fouled Anchor– Admiralty existed from 1801 to 1964.
  3. AM– Air Ministry only in existence 1918 to 1964.
  4. WD– War Department was formed following the disbandment of the BO in 1855.
  5. WD (dated) – ENo dated examples seem to be prior to 1860’s or post 1890’s.
  6. MOD– As from 1st April 1964 any new boundary stones erected on the boundary of lands used for military purposes will be enfaced “M.O.D. /|\ B.S. No. XX” from the Defence (Transfer of Functions) Act 1964, Wording of Lands Notices, Bylaws.

Variety of Design

What is common among all stones is the broad arrow, with the exception of Admiralty stones that bear the fouled anchor. Map 2 is an Ordnance Survey map of Chattenden Barracks in Kent. Here, as in Map 1 of Fort Halstead, there are WD boundary stones marked, but also marked are ‘Stones’ and ‘BS’ for boundary stones with a reference number.

The following markings can be found on stones alongside the broad arrow:

  • BO – Boundary of the (Board of) Ordnance
  • BS – Boundary Stone
  • WD – War Department
  • A – Admiralty
  • AM – Air Ministry
  • MOD – Ministry of Defence
  • No. X – Number (sequential)
A reference guide to some of the variations of stones that have been found spanning the past 200 years.

This article was originally published elsewhere and has been reproduced with permission.

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