2022 Knowe of Swandro Excavation
Excavation at the site of Swandro resumed in 2022 after a gap of two years due to the Covid pandemic. The seaward side of the central roundhouse, which is under high tide level, had suffered greatly from erosion during the intervening period. The effects of tidal action combined with groundwater is leading to the loss of finer deposits between and underlying the stones forming the walls; in the intervening period there has been a recordable loss of archaeology. Some wall faces have partially collapsed and the wall coursing is tipping towards the sea due to the loss of underlying material.
The loss of finer material from the waterlogged underlying deposits due to tidal suction has also had an effect on the more substantial walling that survives above the high tide level. Here there was visible movement of structures including the opening of joints in walling and cracks in large stones together with a measurable loss of height due to the removal of underlying sediments by tidal action. The excavation and recording of the eroding part of the site is important in providing a record of movement, stone wear, and sediment loss by the use of laser scanning which can be compared to previous data sets from the site.
Structure 5 showing orthostatic divisions, hearth and quern embedded in floor.
Alongside the loss of archaeological deposits, the amount of beach material deposited over the site since 2019 was problematic and slowed the rate of excavation, restricting the area that could be opened. Excavation therefore concentrated on the roundhouse that forms the central focus for the surrounding Iron Age settlement at Swandro. The earliest dates for the construction of the central roundhouse suggest an Early Iron Age date. The building seems to have had an extended period of use, perhaps as much as a millennium, displaying in the architectural complexity a number of constructional modifications. The building seems to have been a significant focus for the surrounding settlement through to the Late Iron Age (Pictish) period. There are also indications that some of the earlier wall faces in the eroding area of the roundhouse have a different focus and possibly belong to a different, earlier structure.
Small Iron Age pot, found complete with its stone pot lid still in place.
The earliest dates for the construction of the central roundhouse suggest an Early Iron Age date. The building seems to have had an extended period of use, perhaps as much as a millennium, displaying in the architectural complexity a number of constructional modifications. The building seems to have been a significant focus for the surrounding settlement through to the Late Iron Age (Pictish) period. There are also indications that some of the earlier wall faces in the eroding area of the roundhouse have a different focus and possibly belong to a different, earlier structure.
The landward side of the central roundhouse had fared better, having suffered less erosion. Here work concentrated on examining first century floor deposits in a large cell to the north of the central passage. This cell, termed Structure 5, had originally been formed by large set upright flags or orthostat. The cell had later been blocked off from a central area or corridor by a wall dating to the later Iron Age. The floors of this cell provided evidence for several hearths and rich ash-based floor deposits containing a variety of artefacts including two glass toggle beads and worked bone artefacts associated with textiles including a long handed weaving comb, spindle whorl and needles. A worn rotary quern top stone was set into the floor. Artefacts from these floor surfaces suggest that this phase of occupation dates to the first century AD.
Rare Iron Age toggle bead, one of two found during the 2022 excavation.
The central corridor appears to have been modified in the Later Iron Age (Pictish) period. The entrance to Structure 5 had been blocked and a new single-faced dry-stone wall divided the passage from the landward cells. The passage led to partially-eroded occupation levels denoted by paving, hearths and what seems to be a small furnace surrounded by fragments of glassy slag. This feature is not yet fully excavated but appears to be remarkably similar to one excavated at Mine Howe. Other indications, including archaeomagnetic dates from one of the hearths in 2019, would suggest that all these features are late Iron Age in date.
This phase of occupation (and indeed occupation of the central roundhouse) appears to have ended with a deliberate demolition event which was recorded in detail in 2022. The dividing north wall of the passage had been collapsed on to its side. A series of wall elements and a number of collapsed orthostats all indicate a major event which appears to coincide with the lowering of the outer walls of the roundhouse by stone robbing. The midden sealing these events which was excavated in previous years contained artefacts strongly indicative of Viking culture which suggests that this demolition event relates to the arrival of Scandinavian peoples.
View across central roundhouse showing the collapse of the walls.