Aspull Ring Ditch Project

Excavations (Season1)
Research (Season1)
C14 Dating (Season1)
Excavations (Season2)
C14 Dating (Season2)

Our Site Diaries detail our daily progress over each year,
for Season1 (2022) 
for Season2 (2023)
for Season3 (2024)

We first became aware of this feature when Steven Twigg (formally of STAG – South Trafford Archaeology Group) contacted us with an aerial image in 2019. The crop mark shows up quite clearly as a dark green circle and seems to represent a circular ditch around 40m in diameter. Viewing various other aerial images spanning a number of years confirmed the mark to be more than just a temporary agricultural feature.
The size of the circle would suggest something prehistoric and probably older than Iron Age as it is certainly bigger than a roundhouse. The LiDAR image however revealed the site to have a shallow mound in the centre. This would suggest a Bronze Age barrow (similar sized ones can be seen at Normanton Down in Wiltshire). Its central mound and continuous surrounding ditch would suggest a Type 2 Bowl Barrow as classified by Historic England (ref).

Other features are also noted on the LiDAR image.  About 230m to the south on the other side of the road leading to the Farm, another circular mound can be seen. This is quite visible on the ground, but its size would suggest that it’s a natural feature probably a product of glacial activity. A linear feature runs for 370m (or perhaps more) diagonally to the northwest just 50m north of the ring ditch feature. This feature seems to relate to an old field boundary which is shown on early maps.

Or ring feature site lies in an open field which gently slopes towards the east. From the site, there are extensive views over the fields towards Bolton to the east (the Wanders football stadium can be seen in the distance lying at the foot of Winter Hill). To the northeast are the moors of Anglezarke and Winter Hill where prehistoric sites are know. In the middle distance, Borsdane Brook runs from north forming the boundary of the Wigan Metro Borough. On our first site visit, we were able to talk to the landowner who showed great interest and allowed us to wander over the field. We attempted drone imaging, but this failed to detect anything. However, the shallow mound was just about discernible on the ground.

The pandemic in 2020 stopped any further activity but in May 2021 Chris Drabble carried out a comprehensive aerial drone survey. This revealed a dry central circular area, 23m diameter rising to a height of 1.4m and surrounded by a further damper area 6.5m wide. This seemed to confirm that the feature is man-made.

In the Autumn of 2021, we carried out a resistivity survey of the site with very encouraging results as reported in our October Newsletter (No.246). Our two scans covered an area 50m x 46m and revealed the existence of below-ground archaeology in the form of a huge circular feature roughly corresponding to the aerial imagery, with central targets and possible outer bank in the southwest corner.

The next step would be to carry out some form of excavation but first we needed a Project Plan to know how this would be undertaken by setting out our aims and objectives and formulating a methodology. We envisaged that excavations would be carried out in phases, the first phase being an exploratory trial trench (no more than 2m x 11m) across a section of the circular feature. The suggested position would cover a rare area where crop marks from both the Google Earth and ESRI aerial images more or less coincide with the result from our resistivity survey.
The second phase would be to determine the extent of the ring ditch (if that’s what it was) by putting more trenches in areas where we expected the ditch to be. The final phase would be to explore the interior to find out the nature of the mound i.e. if it’s manmade or natural and if manmade, its purpose (was it a funerary monument or just ritual).

Excavations (Season1)
Phase 1. We started work early in 2022 and, fortunately for us, we had a farmer who was not only as keen as we are to find out what is in his field, but also quite obliging when asked to help with removing the topsoil for us. As soon as this was done, we were able immediately to detect a colour change in the sub-soil indicating the location of the ditch. A few visits later and we had the whole ditch section exposed. This revealed it to be huge – over 3.5m wide and 1.5m deep. To our surprise, the steep sides had not only cut through the hard clay, but also bedrock leaving a flat bottom almost three metres wide. The section revealed two layers of soft sandy clay material filling, showing a recut or perhaps two periods of backfilling (or even just settling of the first fill). Strangely though, apart from this, and the odd thin band of dark material, there were no signs of silting and the floor was generally clean suggesting the ditch was not left open to fill naturally, but backfilled in a single session. Without any finds, we couldn’t put a date on it, although the size of the ditch would tend to suggest something Neolithic rather than Bronze Age. A thin band of dark material from the very bottom of the ditch produced a small piece of charcoal large enough to get a carbon 14 date. With funding from CBA NW, this was duly sent off to the labs in Oxford, but it was towards the end of the year before we received the result. To our surprise this came in at 1501 (95.4%) 1425 cal BC i.e. mid Bronze Age – however it did confirm that we had a prehistoric ditch which was the aim of our first phase.

Phase 2. For our second phase we selected our next trench in an area where the images and survey results were less clear, i.e. on the westside quadrant of the circle. To our big surprise, Trench 2 revealed nothing apart from sub-soil and a layer of soft sandy clay lying on top of the hard natural clay. We were greatly relieved therefore when Trench 3 (dug on the southeast quadrant) revealed the tell-tale colour change in the sub-soil. When fully dug out, gratifyingly it revealed the same structure as in Trench 1 i.e. rock cut with a flat bottom (albeit slightly smaller at 3m wide but slightly deeper at 1.6m). Trench 4, dug on the southwest quadrant, once again revealed the same trapezoidal shape, only this time bigger than Trench 1 (almost 4m wide) and deeper than Trench 3 (at 1.75m). Again, there were no signs of layering or silting apart from the dip of a secondary fill. We now had three confirmed ditches, all cut into the natural hard clay and underlying bedrock. Assuming our feature to be a perfect circle, we located our next trench (Trench 5) in an area where we expected the ditch to be in the northwest quadrant. Things again did not go to plan however as our ditch turned out to be as much as 5m further out from where we expected it to be (and frustratingly under our spoil heap). After moving this, our excavation once again revealed the usual shape but slightly smaller than the rest at just over 3m wide and 1.3m deep.

Termini. We were aware now that our feature was not perfectly circular and had a possible entrance on the west side. This, together with the size of the ditch, was strengthening our conviction that this was something old than Bronze Age, a Neolithic henge perhaps. However, there were no signs of an outer bank and we had a mound on the inside (something not normally associated with henge monuments).

But was there an entrance? – if the feature was oval-shaped, had we just missed it? Our next trench (Trench 6) therefore was located just a few metres south of Trench 2 where our entrance was perceived to be. Straight away, signs of the ditch appeared exactly where we expected it to be on the circular projection. Without fully digging it out, we moved straight on to open a larger area (Trench 6a) further towards Trench 2.  Gratifyingly this produced the expected shape of a ditch terminus which, when fully excavated, revealed it be semi-bowl shaped (well, almost). The only sign of bedrock was at the bottom of the trench so it was difficult determining the exact profile. This was particularly true at the very end where there was evidence of extensive tree-root damage (further investigations of this area produced what appeared to be a slope leading into the ditch).

We were now confident we had an entrance, so we began to look for the north-side terminus. By now we were using an auger (a 20mm by 1m long screw) to give us some indication where to look. We planned to chase the ditch from where we had found it in Trench 5 towards Trench 2.  Augering however can be misleading, particularly where the ground is stony, as was the case in the area next to Trench 5. This led to us digging our next trench (Trench 5a) right next to Trench 5 thinking this was where the terminus was (although we knew this was strange, as it would have made the entrance huge). Fortunately, this turned out not to be the case but it did reveal something even stranger. When the two trenches were expanded and joined together, to our surprised we found a junction of two ditches. When the profiles were fully excavated, the ditches seemed to be slightly out of alignment and even stranger, revealed to be square ended. Using the auger, with due diligence this time, we located our next trench (Trench 7) a lot closer to Trench 2. This thankfully revealed the north-side terminus showing the entrance to be 6.5m wide. As with the south-side terminus, our initial investigations showed it to have a semi-bowl shape profile but this time there was no sign of an access ramp. Our last trench (Trench 8) was dug on the north quadrant just to confirm the shape of the feature in that area. We now had a clear picture of our monument, i.e. it was slightly oval-shaped with an entrance on the west side and a junction between two separate sections on the northwest axis. There could well be more junctions but this could only be determined by opening more trenches  (augering not being particularly reliable).This concluded our first season of digging on this remarkable site. Next season would involve investigating the central area but you can see much more detail of this year’s work on our Site Blog Diary here .

Research (Season1)
During the closed season we continued our research to try to understand what we had discovered. Apart from the charcoal giving us our C14 result, we had no other finds, so we were relying on typology alone. However this was not easy, as there did not seem to be many sites of similar size and form. We did find sites with similar configurations to ours known as causewayed ring ditches. A group of these in North Wales had one in particular at Pentrehobin, that had similar proportions to ours with a 44m diameter, 4m wide by 2m deep ditch. Another group on the Isle of Thanet in Kent, excavated in the 1970s and 80s, had one called Lord of the Manor III, which had a central mound like ours. Perhaps the closest proportionally to ours though is a site not far from Stonehenge called Coneybury henge. As with ours, it has no outer bank (which is assumed to have been ploughed out) but unlike ours it didn’t have a central mound.

All these sites are generally dated to the late Neolithic / early Bronze Age and some contain burials, but rarely have central mounds. When these do occur, it suggests maybe a transition period when the newcomers reused the old monuments, before building their own traditional ring ditches and barrow forms.

C14 Dating (Season1). As mentioned before, our first result from Trench 1 came in at 1501 (95.4%) 1425 cal BC. Towards the end of year we were ale to retrieve two more samples of burnt wood which were duly sent off for testing. This time they had been retrieved from the bottom of Trench 5 from what appeared to be a small cairn made of alternating layers of stone, clay and sand. One sample went to the Chrono14 labs at Queens University Belfast, the second to CARD which a free service specifically set up for amateur groups. The result from Queens gave a calibrated Median Probability – 1648 BC and from CARD – 1687 (95.4%) 1535 cal BC. Although the dates range over 200 years, it’s still in the mid Bronze Age range. CARD identified the wood species as oak, which they say is less accurate than say willow which has a much shorter life span. It must be remembered though that all these dates indicate when the ditch was last open, not when it was constructed (which suggests that the ditch had been maintained by the Bronze age people)

Excavations (Season2)
Coring. Work started early in March with a coring survey on the southern quadrant between Trenches 3 and 4. This was an experiment to see if we could detect the ditch and whether it continued or were there any gaps of junctions similar to Trench 5/5a. We used a one metre long 20mm diameter corer on a one metre grid and the result proved quite positive. We were able to confirm that in this quadrant there were no large gaps although there was the possibility of a junction which we could investigate at a later stage. With this success our intention will be to do another when we get chance on the east quadrant where, if there is another entrance, that’s the most likely location (i.e. opposite the west entrance).

Termini. Before starting on the central mound we had some unfinished work to do in the ditch terminals. In Trenches 6 and 6a (on the south side of the entrance) we final joined the two together revealing a fine bedrock floor. Similarly in Trench 7 on the north side of the entrance the bedrock floor was also revealed. This showed that, although the upper section of the terminal was semi-bowl shaped, the lower section was squared off similar the the other end of this ditch section in Trench 5a. However is was becoming less certain about the original ground surface on the external side of the ditch in both these areas, something which needs further investigation at a later date.

Interior. Work on the internal area of the ring ditch began in May 2023 by asking the farmer to use his machine to extend Trench 1 towards the centre (we chose Trench 1 as this had a more positive natural surface which we could use as a reference to define the nature of the mound). Showing great dexterity he delicately removed the topsoil and as he moved away from the ditch, the underlying subsoil could be seen giving way to soft, orange coloured, sandy clay. After about six metres, a well-defined stony layer appeared which we presumed to be the edge of a possible central cairn. The stones, which lay on top of the soft sandy clay, seemed consistent with the bedrock material we had encountered in the ditch and therefore likely to have come from it. As we extended the trench (we were now calling Trench 1a) further towards the centre of the mound, large areas of burning were revealed overlying the stones. This was sealed beneath a layer of mottled sandy clay which was particularly thick in the central area. Banding in the clay suggested it could be the result of turfs. Small flints began appearing – mostly debitage but there was one identifiable thumb-scraper (likely to be Mesolithic but could also be Bronze Age). To add to our excitement, a small polished hand-axe appeared amongst the stone scatter. It was made of sandstone, a material unsuitable for use as a useable tool. Also its size suggested it was a ‘representative’ ceremonial deposit (similar examples have been found on Orkney).
As we extended the trench further across the central area (Trench 1b), more areas of burning were showing up. This was represented by dark charcoal-rich patches and red stained stones. It was obvious that there had been a great deal of burning in the central area of the ring ditch. The burning layer was represented in the section by a thin black line. It was also becoming apparent that this line was topped by a band of red sandy clay material, varying in thickness and colour from bright orange to crimsons. These layers were sandwiched between the stones and the overlaying mottled sandy clay layer. To determine how far this arrangement went away from the centre we asked the farmer to open another trench on the southeast side. He did this by extending Trench 3, removing the top soil all the way up as far as the new trenches in the centre but leaving a 2m baulk for access (this became Trench 3a). Working from the central area southeast- wards, the outer edge of the stony area was soon found, but seemed to be more ragged than the edge in Trench 1a. By expanding the trench on either side, more stones were revealed, but there were also areas of soft sandy clay devoid of stone lying under the burning and mottled clay layers. It was while pursuing the extent of the burning layer in Trench 3a, away from the centre, that we came across our next most exciting find. Just below the topsoil, amongst a patch of burning, small pieces of cremated bone started appearing. Careful excavation revealed the rim of a pot just over 30cm in diameter. Further investigations revealed it to be only the top part of a cremation urn, the rest being apparently destroyed by ploughing. This was not a wholly negative result, though, as it also told us that the covering mound must have been significantly higher in the Bronze Age. It was obvious the remains lay in a pit, cut into the mottled clay layer and seemed to be lying on top of the burning layer. As we were most likely dealing with human remains, we had to contact the local coroner which involved a day spent getting phone calls from puzzled police officers. This ended with a meeting on site by two officers and two small containers of cremated bones were removed for possible forensic examination (for a crime, they had to admit, they weren’t likely to solve). Removing anymore fragments of bone would require permission from the coroner and even a licence, so the remains were covered over to protect them from the weather (and also the site dog, Snowy who seems to have a penchant for our cremated bone). Further fragments of bone were turning up in areas on the northeast side of Trench 3a which were all treated in the same way. We now had positive evidence that we were dealing with the site of an large funerary monument and great care needed to be taken in our further excavations.

A sandy clay patch, also on the northeast side of Trench 3a, appeared to be different than the other areas of sandy clay devoid of stone. Here, it was obvious that the overlaying burning and mottled clay layers had been sheared off the top of what appeared to be a rising mound of sandy clay. It was while investigating this sandy clay mound that our next exciting discovery turned up. This was another ceramic pot, buried upside in the mound (significantly buried, not in a cut in the mound). It was much smaller than the the previous find but, a part from a large crack, seemed complete. Closer inspection revealed an incised criss-cross pattern on its surface. Its size and location, suggested a much earlier phase in the life of the monument. Although no bones were found associated with it, we realised this would again need care handling so, until we could arrange for its careful removal, examination and storage, we decided to leave it in situ, covering it over as before to protected from the elements (contact with Ian Miller at GMAAS produced a kind offer of a place at the Salford University Labs for its study).

Expanding Trench 3a further in the northeast direction produced one more important find – a sherd of pottery embedded in the stony layer. The criss-cross pattern on its surface indicated it was clearly from another Bronze Age urn. This time the pattern had not been incised but impressed perhaps by thin cord or serrated wheel which suggests a later date. This isolated sherd also indicated there was another cremation somewhere but further extension of Trench 3a failed to find any. This, together with our other finds, did show however that our site had been in use over a long period of time.

To investigate the full extent of the stony and burning layers, Trench 1b was extended in the northwest direction towards Trench 5 in the northwest quadrant (producing Trench 1c). Here the extent of these layers could be seen but surprisingly they seem to be diving under a new layer of stones embedded in the subsoil which had started to appear. By the time we reached Trench 5, this new stony layer had disappeared leaving just a soft sandy clay lying under a thick layer of subsoil. This is what we had discovered the previous year when Trench 5 was excavated. It wasn’t clear at the time what was happening to the natural ground surface we had established around the edges of the ditch. This consisted of a hard compacted clay embedded with small pebbles (a typical glacial till). However this seemed to quickly disappear after just a couple of metres away from the ditch to be replaced by the soft sandy clay, eventually being topped by the thick layer of subsoil. The point where the compacted clay layer disappeared and the soft sandy clay appeared, was marked by a small outcrop of bedrock. When the area between this and the end of the trench was further excavated (now referred to as Trench 5b), we were able to establish a hard compacted clay layer laying under the soft sandy clay. However the issue about whether this soft sandy clay layer was manmade or a natural deposit, had still not been resolved, despite it appearing to be spread all across the whole internal area of the ring ditch. It was hard to imagine it being natural but, if was manmade, where did the material come from and why was there little or no evidence of its deposit in the form of banding (similar to the sections seen in the mottled clay layer).

In the main area of Trench 1b, larger stones where poking through the small stones in the stony layer. To investigate the extent of these stones, the stony layer was cut through down to the underlying soft sandy clay. This revealed a substantial area of large, mainly flat, stones. There was no obvious pattern to their distribution – a causeway didn’t seem plausible as, although embedded in the stony layer, most were lying below the upper surface of the stony layer.

Further investigation of the sandy clay mound in Trench 3a revealed it covered on its southwest with the stony layer. However on the other side a layer of stones seem to be embedded in the mound. Larger stones were also being found buried deep in the clay of the mound. One of these stones produced our final and most unusual find of the season. Inscribed on the lowest section of the block were a series of parallel lines. These were not the usual random spirals or cup marks you get in the Neolithic but quite straight and evenly cut lines. As far as we can tell, this is totally unprecedented for this period. A much smaller stone with similar grooves had already been spotted in the stony layer but, at the time, had been dismissed as a possible intrusion. When yet another small stone with with similar but more pronounced grooves, appeared in the small stones embedded near the surface of the mound, that we realise we had discovered something very peculiar (at the time of writing we not been able to find anything comparable).
Thus ended our second digging season – a season that has seen lots of interest from archaeological groups from across the region. Many have volunteered their services, including groups from the Wyre, Liverpool and even Cheshire. We also have had a session from Manchester’s Young Archaeologists Club who thoroughly enjoyed their day with us.
As usual you can find out our detailed progress this season our Site Diary here

C14 Dating (Season2). During the year, we took a sample of charcoal from inside our first urn and from a large patch in the central area of Trench 3a. Both were duly sent off for analysis at Queens University (grant from CBA NW applied for). Result came back within a couple of months, again with an mid Bronze Age date; however this time a full 200 years earlier (i.e. cal Median Probability -1820 BC). The dates from both sample in effect were the same, which suggests that the burning event, the cremation and the creation of the mottled clay mound, all occurred at the same.  We do however have an earlier phase represented by the sandy clay mound which has our second urn in it (and possibly an even earlier phase if we consider the ring ditch to be a Neolithic henge).