Archaeology in Alderney: Excavating the biggest Iron Age and Gallo-Roman site in the Channel Islands

In June 2017, contractors digging an electricity service trench, just inland from Longis Bay in Alderney, began to find human bones. Archaeologists from Guernsey quickly flew up to investigate, and so began six (COVID-19-interrupted) years of research into the biggest, and best-preserved, Iron Age and Gallo-Roman site in the Channel Islands. With another excavation just concluded, this seemed a good opportunity to summarise the results so far, as Philip de Jersey reports.

Longis Bay is well known, at least among Roman archaeologists, for the β€˜Nunnery’ – an extraordinarily well-preserved shore fort of the late 4th century AD (described by Jason Monaghan in CA 261). This new site, discovered in 2017, lies along the 19th-century road that leads inland from the Nunnery, and initial finds included a cremation burial, an inhumation, and several stone cists – all of which were radiocarbon-dated between the early 2nd and late 1st century BC. There were also structures, probable Roman walls, at various points in the trench, and a 2nd-century AD burial of a neonate (a baby who died at or around the time of their birth).

We went back in the spring of 2018 to carry out a resistivity survey in the Paddock Field (on the other side of the road to the cable trench), followed by an excavation that summer, and returned again in 2019. Three trenches dug during this work revealed a wealth of Gallo-Roman structures and finds, underlain in at least one area by in situ Iron Age burials. Three burials were excavated: a stone cist dated between 170 BC and AD 90, and two earlier inhumations, dated between the mid- 8th and end of the 5th century BC.

As the image (below) demonstrates, the archaeological deposits are deep: the burials were almost 2.5m below the ground surface, and digging through wind-blown sand presents considerable problems with keeping the baulks stable. The sand has, however, ensured that the quality of preservation of the bones is exceptionally good, and more generally its presence ensured that Longis Common has remained almost wholly undeveloped since the late Roman period.

Image: Phillip de Jersey, Culture and Heritage – States of Guernsey

Following the interruption of 2020-2021, a GPR survey was carried out in June 2022, and then this past May we excavated for three weeks in the Coastguards Field, west of the site explored in 2018-2019. The results were unexpected. Instead of the structures seemingly indicated by the GPR, we found a thick Roman midden deposit and, below another layer of wind-blown sand, a series of stone features, including what appear to be two empty cists. A skeleton (below) was found associated with another group of stones, however, and pottery from surrounding contexts suggests an earlier date than the previous finds, perhaps in the Bronze Age. We await a radiocarbon date for the skeleton with interest.

Image: Phillip de Jersey, Culture and Heritage – States of Guernsey

In the meantime, we are considering our options for 2024. We are probably beyond the boundary of the Roman settlement in Coastguards Field, so we may move back down the hill into the Paddock, where we know there is excellent preservation of Iron Age and Roman deposits. The lure of good finds is attractive, but tempered by the responsibility of carrying out archaeological excavation to the best possible standards: our resources are limited, and the isolation of Alderney (which has contributed to the preservation of the site) makes travel and accommodation difficult and expensive. One option is to investigate setting up a field school, or working in tandem with a university department. Interested? Please contact me!