A guide to archaeological techniques

The Galloway Picts Project will undertake:

  • a topographic GPS survey to establish a modern plan and 3D model of the entirety of this site and enable accurate targeting of Thomas’s previous trenches;
  • a detailed laser scan survey of the Pictish/Ogham inscribed stone to enable specialists to translate the Ogham inscription and assess the comparative inscribing methods;
  • the re-excavation of the previous excavation trenches and limited sample excavation of the trench bases and sections in order to recover and record environmental and artefactual evidence from secure contexts to enable radiocarbon dating and archaeomagnetic dating and characterisation of specific archaeological features within the site, such as the vitrified rampart, the outer rock-cut ditch, the rock cut basin, the summit interior, and the outer ramparts;
  • specialist analysis of the recovered evidence and publication of the results in an appropriate archaeological journal.

Topographic Survey

The first phase of fieldwork will commence with a topographic GPS survey of the entire site, undertaken by the Royal Commission of the Ancient and Historical Monuments of Scotland. The resulting topographic plan and 3D model of the site will be used to identify the exact location of Thomas’s trenches.

RCAHMS survey plan of Trusty’s Hill. Derived from information compiled by and copyright of RCAHMS

RCAHMS survey plan of Trusty's Hill

Laser scan

A detailed laser scan survey of the inscribed stone will be undertaken by the Centre for Digital Documentation and Visualisation, a partnership between the Glasgow School of Art and Historic Scotland. Their team will clean the lichen from the stone in advance of a digital high definition 3Dscan survey of the stone surface by their stone conservator. The results will be processed and the appropriate resulting 3D model illustration will then be submitted for detailed examination by an expert from the University of Glasgow in order to translate the Ogham inscription and identify the method of inscription used for the Pictish Symbols.

Excavation

The re-excavation of Thomas’s trenches will be undertaken by our team of volunteers. All on-site recording, whether written, drawn and photographic, will be to Institute for Archaeologists (IfA) standards, as guided by archaeologists from GUARD Archaeology, which is an IfA Registered Organisation, who will be on hand during the entire process.
Photographs will be taken of each trench area prior to the commencement of the excavation. The excavation of each trench will commence with de-turfing by hand. The turfs will be stacked appropriately face down on the grass of the adjacent ground and regularly checked and watered if necessary to ensure that they recover upon re-turfing at the completion of the excavation. The backfill soil will be stored separately on terram sheets laid out across the adjacent ground, after being dry-sieved.
The backfill soil at each trench location will be removed in spits to the first undisturbed archaeological horizon or, where none is found, to the natural subsoil. Any archaeological features encountered within the trench sections (the sides of the trench) or trench bases (the bottom of the trench) will be cleaned by hand and sample excavated (no more than 0.10 m into each feature encountered in a trench section or 25-50% of each feature encountered in a trench base) in order to extract sufficient evidence to determine their date, form and nature. A full record of excavated features will be made using a single context planning system using pro forma sheets, drawings and photographs in order to determine their character, extent and stratigraphic relationship with other archaeological contexts. The full depth of sections of each trench will be recorded by written, drawn and photographic recording. All levels will be tied into Ordnance Datum and the trenches accurately located with the National Grid.
On completion of the recording of the excavation trenches, and the laying of terram across the base of the trenches, the backfilling of trenches will be undertaken by hand, under the supervision of GUARD archaeologists. Backfill soil will be backfilled first and then the turf laid back over the surface, thus restoring the site to the same condition in which we found it.

Specialist Analysis

All re-excavated backfill will be dry-sieved on-site and all finds encountered during this process will be recovered. All other archaeological finds will be collected by their separate archaeological contexts. Significant small finds will be three dimensionally located prior to collection. All finds will be cleaned and subjected to specialist assessment. Conservation of finds will be appraised to allow for specialist study.
Environmental samples, targeting charcoal for radiocarbon dating, vitrified stone for archaeomagnetic dating, charred macroplants for environmental assessment and soil micromorphology for soil development and the formation of the ditch fill deposits, will be taken where appropriate from secure stratigraphic contexts in trench sections and bases. Each bulk sample taken from archaeological features and horizons evident in the trench sections and bases will be assessed for palaeo-environmental evidence. Samples of in situ vitrified stone from the rampart will be extracted by archaeomagnetic dating specialists from the University of Bradford, and taken for archaeomagnetic dating. Other than the sampling of archaeological features exposed in the trench sections and bases, no further excavation of archaeological features will be pursued.
The initial specialist assessment of environmental and artefactual remains recovered during the fieldwork will be undertaken and presented, along with the fieldwork results, in an illustrated Data Structure Report prepared by the Project Directors. Hard and digital copies of this report will be produced and lodged, as a minimum, with the landowner, Historic Scotland, the Dumfries and Galloway Council Archaeology Service and the National Monuments Record for Scotland.
The Data Structure Report will include a Post-Excavation Research Design, which will detail the specialist analyses to be undertaken and the form of the publication report. This final phase of the research programme will comprise appropriate post-excavation analysis, reporting and publication of the results. This will include specialist analysis of artefacts, plant remains, soil micromorphology samples, radiocarbon dating, archaeomagnetic dating, Pictish/Ogham translation and inscription methodology and a discussion of the results. It is proposed that the results of the excavation will be submitted for publication in the Transactions of the Dumfriesshire and Galloway Natural History and Antiquarian Society.