Publication Account
Date 2006
Event ID 1019541
Category Descriptive Accounts
Type Publication Account
Permalink http://canmore.org.uk/event/1019541
THE FORT
The Castlelaw fort (fig 3), which is a Guardianship monument in the care of Historic Scotland, is the only fort within the CDTA, and, like other categories of settlement from the 1st millennium BC, it forms part of a larger distribution of broadly similar sites, some of which survive as upstanding monuments and some as cropmarks. Despite two small-scale excavations (Childe 1933; Piggott & Piggott 1952), the exact nature of the defences of the fort is not fully understood. The excavations revealed a complexity of timber features, including palisade trenches, but the sequence of events can only be resolved by further excavation. If the fort follows the pattern of other sites for which there is dating evidence, then it is likely to have been occupied in the second half of the first millennium BC and gone out of use before the end of the millennium.
The Commission’s first association with the fort was a survey undertaken in 1915, with the resulting plan (fig 5) appearing in the Inventory of Midlothian and West Lothian (RCAHMS 1929). Although this plan records most of the major features of the fort, it does not acknowledge the presence of the later cultivation remains. Nor does it appear to recognise the devastating effect that this cultivation has had on the fort, especially on the south side, where the ramparts and ditches have been converted into cultivation terraces.
The survey of the fort (fig 6), which was carried out by the Commission in November 2005, was undertaken using a selfreducing alidade and planetable, with control provided by a series of pegs, the positions of which were recorded by Global Positioning System (GPS) equipment. As well as obtaining new information about the monument, the survey recognized that the lack of contemporary remains within the fort was probably as a result of cultivation in the interior. While this may have seemed a reasonable conclusion to draw beforehand, no cultivation remains were recorded in the interior of the fort until they were spotted during the course of survey. It is somewhat ironic that the very slight remains of that cultivation, in the form of very low scarps, were not detected by either aerial photography or by sophisticated survey techniques, but by the investigators seeing the features in perfect conditions - in late afternoon when the sun was very low in the south-western sky.
As part of the Commission’s ongoing assessment of the practical uses of GPS technology, a terrain model of the fort (fig 7a) was achieved as a result of taking approximately 17,000 height measurements across and around the site. The exact role of terrain modelling in archaeological recording has yet to be determined, but, in the meantime, one of the benefits is being able use software to examine, on screen, monuments in three dimensions, either in isolation or in wider topographical contexts.
Another useful tool, the potential of which is still to be fully explored, is that which allows a hachured plan derived from an alidade survey to be draped over the terrain model (fig 8).
THE SOUTERRAIN
The souterrain at Castlelaw, which is built into one of the disused ditches of the fort, is one of relatively few souterrains south of the River Forth. Like a number of its southern counterparts, it shares many of the architectural traits commonly present in the main concentration of souterrains in eastern Perthshire, Angus and northern Fife. It has a curving drystone-built passage, with an entrance at one end and a rounded terminal at the other, nd there is a subsidiary chamber opening off the main passage. Roman material found during its excavation (Childe 1933) indicates it was in use in the second half of the second century AD. Thus it appears to be contemporary with most of the other souterrains in eastern Scotland, including the one at Crichton Mains, some 20km to the east, where Roman masonry, datable to before or about AD 160, is built into the walls and roof of the passage.
A cupmarked boulder, probably dating to the period between 4000 and 2000BC, appears to form part of the top of the passage wall of the souterrain close to the south end of the east side. However, the stone is not mentioned in any previous accounts of the site, including the excavation report, and the circumstances of its discovery remain unknown. The full dimensions of the stone cannot be determined, but five cupmarks (two of them oval) are visible on its upper surface.
BOUNDARY MARKERS
An unexpected aspect of the archaeology of Castlelaw was the presence of nine boundary markers, which define the Guardianship area around the fort and souterrain. These markers include three distinct forms, reflecting different periods in the definition of the boundary.
The earliest markers probably date to about 1924, when the site first came under State protection, and comprise two short sandstone blocks, measuring only 0.14m square in section, which stand on the east and west-southwest sides of the fort respectively. Each stone bears an incised arrow symbol on its flat top, pointing towards the centre of the fort.
Four of the other seven markers in the circuit are cast concrete pillars, measuring 0.23m square in section, and varying in height up to 0.38m (fig 9). The upper surfaces again bear arrow symbols, this time impressed,pointing to the centre of the fort. These markers may have been in place by 1937, when the Guardianship area was consolidated following the transfer of the land from the War Department to the Ministry of Works (RHP 319). They must have still been in place when the Ministry of Works planned the fort in 1955 (RCAHMS MS: MLD/13/5), though only two markers, one of them displaced are shown at the east end of the fort.
When the Guardianship area was enlarged in the mid 1950s three of the boundary stones at the west end of the fort were retained in their existing positions and three at the east end were simply moved to their new positions. Two new markers, little more than crude blocks of concrete barely rising above the level of the surrounding turf, were inserted to mark angles in the new fence-line on the north side. For some reason it appears that the existing marker on the south-south-west could not be re-used, and a third new crude concrete block has been used in its place. A MOW plan demonstrates that all of the markers that are visible today were in place by 1958.
Though not boundary markers in the traditional sense, the two star-signs, on poles immediately east of the present fence-line around the uardianship area, are a form of demarcation. They were erected by the military some time before 1955, and they basically instruct troops that no digging is allowed beyond the line defined by the signs
Information from 'The Royal Commission on Ancient and Historical Monuments of Scotland: Field Guide 2006'.
