Archaeology Field School

Archaeological excavations at The Berth, Shropshire

Between 2016 and 2025, the University of Birmingham carried out excavations at the Iron Age site called The Berth in north Shropshire, combining student training alongside archaeological research. 

The landscape of Berth Hill

Berth Hill forms a geological island; a gravel mound, rising about 16m above a surrounding wetland. At the end of the last Ice Age, this wetland would have been a lake, gradually infilling with peat, with just Berth Pool to the south of the hill as the surviving remnant. In the Iron Age, perhaps 2,400 years ago, this hill with its surrounding wetlands became the focus for Iron Age activity.

This Iron Age activity is represented by an earthwork enclosure encircling Berth Hill, with a second enclosure on the nearest area of dryland to the northeast. One of the most noteworthy features of the site is the setting of two stone causeways; the first linking the two enclosures across the wetland, and the second extending from this to the drylands to the south.

Investigating the site

Our initial investigations at this ‘marsh-fort’ were focused on these two causeways, which seemed exceptional for any Iron Age context and appeared to make little sense architecturally. Our results demonstrated that these were not actually Iron Age but related to additions made in the post-medieval period, around the 18th century.

Initial excavations focused on understanding the architecture of the site, both to determine the nature of this post-medieval activity and to determine the original, Iron Age route through the site. Through a combination of 15 trenches and 19 test pits, in conjunction with geophysical, geoarchaeological and geomatic survey, we have transformed our understanding of the site, both in terms of its prehistoric origins and its later re-use in the early years of the Industrial Revolution.

Iron Age activity

We now know that people were initially attracted to The Berth for iron smelting, using the bog iron from the surrounding peatlands to generate the raw materials for iron working. A prevalence of pottery relating to the import of salt from Cheshire provides a plausible trade route for this iron. The evidence also demonstrates an intensive agricultural economy dominated by sheep and cattle.

The construction of the enclosures followed the initial smelting efforts, though these continued through all phases of Iron Age activity. As the enclosures were constructed, they were linked by a small causeway crossing the narrowest point across the wetland. Whilst the smaller enclosure lacked internal structures, providing more of an outer gateway to the site, the slopes of the hill within the larger enclosure were terraced, providing spaces for both houses and industrial activity. Atop the hill, a small Iron Age shrine provided a focus for religious activities.

Iron Age occupation appears to have been interrupted by short phases of abandonment. The unstable sediments of the gravel hill provided challenges for occupants with phases of activity were interrupted by periods of significant hill wash, or colluviation. This material infilled hollows between earthworks which then became the surfaces upon which new structures were built. After successive periods of activity, the colluviation was so significant that it completely masked the earthworks on the interior to the site. Despite this, each new phase of occupation included additional iron smelting activity until the site was finally abandoned in the Late Iron Age, perhaps around the first century CE. 

Later activity and quarrying

The site then appears to have remained untouched for over 1500 years later with no evidence for activity in this period. Whilst it was known that quarrying had taken place on the site in isolated locations during the 19th century, the excavations have revealed that this started earlier, in the 18th century, and on a massive industrial scale. This is particularly significant as we have been able to map how this quarrying removed extensive areas of Iron Age archaeology. Our investigations demonstrated that not only were the two large stone causeways actually quarry roads, but much of the earthworks previously considered to be Iron Age ramparts were too.

The extent of 18th century quarrying has re-shaped Berth Hill. This, in conjunction with the identification of the quarry roads has shown that the shape and architecture of the Iron Age site was significantly different to how it was originally considered to be. Driven by the paired requirements of toll roads and canal construction, The Berth was positioned perfectly for the exploitation of its gravel for a variety of purposes. But by the 19th century, memory of this was lost.

Interpreting the site today

Due to the combination of deliberate abandonment in the Iron Age and the impacts of 18th century quarrying, there have been few finds from the site. However, through careful analysis of the stratigraphy and structure of the site, we have been able to unpick its complex architecture, untangling the Iron Age from the later, post-medieval activity, and unlocking a previously unknown quarrying phase which forms a part of Shropshire’s industrial past.