Dinas Dinlle Hillfort Excavation Dig Diary

Day 1

8th July 2022

And we're off! Work commences for our 2022 excavations at Dinas Dinlle coastal hillfort.

We'll be posting daily updates so you can follow the project.

As you can see, we're machine excavating, this will continue until we get down to the geotextile, marking the limit of our 2021 excavations. Next week, with the help of some of our volunteers, we'll begin cleaning archaeological features in preparation for our recording work.

The programme of works for 2022 involves the completion of the excavation of a well-preserved stone-built prehistoric or Roman period roundhouse, these excavations began in 2019/2021.

The roundhouse lies close to the eroding coastal edge of the fort, and the excavation is being undertaken before the area becomes inaccessible and the archaeology destroyed.

This year's excavation is supported by Cadw, the National Trust and the CHERISH project. The hillfort is on National Trust owned land.

Day 2

11th July 2022

It was wonderful welcoming our volunteers on to site today, and we're very grateful to them for their time.

We're also working with several Bangor University students – the project is a valuable opportunity for gaining archaeological field work experience.

Some more background information on the site - the hillfort is set on top of a prominent coastal hill about 7.5km south-west of Caernarfon. The hill itself is a glacial moraine and is a Site of Special Scientific Interest. The site is owned by the National Trust. The hilltop was modified, most likely in the Iron Age, to form a fort surrounded by a huge inner rampart, a deep ditch and a second outer rampart. The western edge of the fort currently consists of a steep cliff of glacial clays, silts, and stones standing above the sea. This is undergoing coastal erosion as a result of both storm damage from the sea and water running off the land. Severe weather events, which are increasing as a result of climate change, are thought to be playing a major part in the ongoing erosion. The western ramparts have been lost over the last few hundred years and the fort is eroding at a rate of up to 0.4m per year.

Day 3

12th July 2022

This week we're also working with local schools. After a GAT classroom session pupils join us onsite for a tour of the hillfort before helping us clean archaeological features.

A recap session follows these site visits.

Today Ysgol Baladeulyn and Ysgol Bro Llifon joined us on site and help us with our excavation work.

Day 4

13th July 2022

Our roundhouse is starting to emerge from the sand!

And today it was Ysgol Dyffryn Nantlle's turn to visit us on site and help us with our excavation work.


Day 5

14th July 2022

Beautiful weather on site today!

Here's a video of our roundhouse and some of our volunteers:


Day 6

15th July 2022

Golf, anyone?

Dinas Dinlle hillfort was used as part of a golf course during the early 20th century, with local newspapers reporting that the course opened in June 1906. Apparently the course closed a year later owing to its remoteness, but appears to have been taken over by the nearby Caernarvon Bay Hotel (now Y Wendon holiday apartments) and continued in use until about 1920.

We've included a plan of the golf course (produced by the CHERISH project, 2018).

With its Welsh language literary associations (the site features in the fourth branch of the Mabinogi), its Second World War Archaeology (see the pillboxes on the north-east side of the fort) and its status as an SSSI (owing to the unique nature of the glacial sediment of the hill the fort is built on), the site has a lot going for it before we even get to the Iron Age and Roman period archaeology!


Day 7

18th July 2022

Come along to our open day, Saturday July 30th. 10.00am – 4.00pm.

Enjoy guided tours of the site and find out about this year's excavations. Free, no booking required.

Park at Dinas Dinlle beach car park and make your way towards the hillfort. Social distancing required.

Dress according to the weather!



Day 8

19th July 2022

We're continuing to excavate our roundhouse in the hillfort interior.

Have a look at the stone facing of the walls – really good condition when you consider this is thousands of years old. It is probably so well-preserved because it was buried in sand many hundreds of years ago. These pictures are of the inner facing in the southern half of the roundhouse.

It's a big roundhouse – 13 metres across, in places the walls are 2.5 metres thick. Its size suggests someone of high status may have lived here. Or it could have been used as meeting place, or a community space. It was probably used for different purposes over time.

We've erected a gazebo on site to provide some much-needed shade!

Day 9

20th July 2022

Sadly there was some vandalism at the site over the weekend, as some of you noticed. Some fire damage on the roundhouse walls and broken glass. The incident has been reported to the North Wales Police Rural Crime Team as a heritage crime.

From Cadw:


Damage or disturbance is prohibited under the Ancient Monuments and Archaeological Areas Act 1979.

If damage is taking place, ring 999 and report an incident of heritage crime. If new damage has occurred, but is not actively taking place,

ring 101 and report the same. In addition, please email us at marking your email “Heritage Crime”.



Day 10

21st July 2022

Let’s have a look at the ramparts at Dinas Dinlle hillfort.

Ramparts are banks forming defensive boundaries. Material dug out from defensive ditches could be used to construct the rampart. The ramparts might have had wooden structures (palisades) built on top of them, making them even higher and more impressive.

See video:

Day 11

22nd July 2022

In the first image below (2021 excavations) can really see how erosion has affected the hillfort. You can see why we place excavation trenches where we do – we want to record the archaeology in this part of the fort before it's lost to erosion.

Surveys by the CHERISH Project calculate that between twenty to forty metres of the western side has been lost since 1900. Dinas Dinlle hillfort could be completely lost within 500 years.

Look at the maps too – you can clearly see parts of the fort are no longer here.


Day 12

25th July 2022

Here are two interesting finds recovered from above the secondary occupation surface in the SW quadrant of our roundhouse.

The first is a ferrous metal ladle/spoon lying face down, and the second, well we're not sure what that is!


Day 13

26th July 2022

Let's have a closer look at the construction of the roundhouse.

The roundhouse is circular in plan, with an external diameter of approximately 13.6m, and an internal diameter of 8.6m. The substantial walls, up to 2.69m thick on the southern side, are of drystone construction and built from large subrounded boulders which form an internal and external wall facing, with generally smaller rounded, subrounded, and subangular boulders and cobbles used to construct the wall core.

The stones on the internal wall face survive up to a height of 1.02m with up to three courses visible in places. Smaller subrounded and rounded cobbles had often been inserted as packing stones into gaps in the base of the wall between and underneath the lower course of inner facing stones. The external wall facing was constructed of generally smaller boulders than the inner face.

The external wall facing appears to have been constructed in a series of straight segments, whilst the internal wall facing is more or less circular. Additionally, the walls flare out on the east side of the building at the location of the entrance, the south wall of which is 2.96m thick.


Day 14

27th July 2022

This beautiful Roman coin came out of the secondary occupation layer in the north-eastern quadrant of the roundhouse today! More information on this as soon as we can!


Day 15

28th July 2022

Recent finds include a quern stone, from the productive south-western quadrant of the roundhouse interior. Found resting on the secondary occupation layer.

Here too is the latest view of the roundhouse, taken from on top of the spoil heap, facing south.

Day 16

29th July 2022

How to make a grand entrance!

Perhaps the biggest ‘reveal' in recent days has been that of the roundhouse's monumental entrance area.

Let's try and unpack some of that.

We now know that the entrance is stepped, down onto the secondary occupation layer, possibly then on to the primary occupation layer too. We surmised from our 2021 work that the entrance appears to taper outwards gradually, this year we've also uncovered two sets of revetment, outside the entrance, which flare outwards. These elements combine to produce a rather grand ‘entrance experience'. A roughly cobbled surface outside the entrance also contributes to the effect.

As well as the substantial stones still in place in the entrance walls, further large stones have been recovered from the entrance tumble. A stone mason from Cadw is due to come out to site and hopefully help us ascertain whether the stones, distinctively shaped, have been worked by hand or are natural.

There's slate in the floor of the entrance too! Could this constitute a use of slate in the Roman period, or is it later infill? The slate does seem to have been sealed by a deposit of tumble containing Roman pottery.

More on the entrance soon – more information is coming to light each day.

Day 17

30th July 2022

Brilliant open day over the weekend!

Thanks to everyone who came along, and thanks to everyone who helped out.

Day 18

We're doing things little differently for today's post.

One of our volunteers, Barbara (or Babs, as we know her), has kindly agreed to let us interview her about her experiences as a volunteer with us Dinas Dinlle. Thanks Babs!

GAT : How's the project going for you?

Babs : It's going very well, meeting up with old friends again and revisiting this amazing site to see what else we can discover about its secrets. Enjoying peeling back more layers of history and uncovering artifacts that were last seen by human eyes almost two thousand years ago.

GAT : What are your reasons for wanting to come and volunteer with us at Dinas Dinlle this year?

Babs : The legendary Dinas Dinlle Roundhouse, I have just finished my third year at this site. I keep coming back (despite the big steep climb up the hill) because I want to see the results as we dig down further into its history. The story of the people who once lived there changes almost from one minute to the next. This dig made the headlines across all the media platforms last year when the whole layout of the massive walls was uncovered. This is such an important part of history, that we need to find out as much as possible about its construction, purpose and many phases of usage before it is lost to the sea. Along with many more areas of our coastline erosion is a major problem here.

GAT : Is this the first time volunteered with us?

Babs : No, I have been involved in many projects since joining GAT in 2019. My first outing was to clear the overgrown smithy at Pentre Berw, my walking stick came in very handy for hooking onto large bramble bushes and dragging them up into a position where they could be chopped off with the large secateurs.

My first ever dig was at Pen-y-Bryn recording the barracks where the quarry workers lived, this involved a lot of measuring and drawing of all the doorways, window recesses, lintels etc. We also had a lot of discussion about whether things had always been what they appear as today or if they had been modified at different stages of the building's existence. For example, was that window always a window or is it a partially closed doorway. I met Louise and Sarah on this dig, and we are now firm friends and often meet up to visit interesting places.

One of the most interesting sites was being allowed to excavate the area just below the Segontium Fort in Caernarfon. Hundreds of artifacts were found here, and this is where Louise and I began our “winter” job carefully cleaning and cataloguing all the pottery and other objects we and other people had found, the artifacts come to us from many different GAT sites.

We have also excavated a Neolithic Axe making site high up the mountain behind Llanfairfechan. This year will be our third visit to this site, it's nice to keep going back and uncovering more history.

GAT : How did you first hear about Gwynedd Archaeological Trust?

Babs: Having been an avid watcher of Time Team for some twenty years I had decided that this was going to become my hobby when I retired. I found out about GAT from a lady who volunteered with the Anglesey Archaeology people. I kept a note of the information and the year after I finally managed to retire, I replied to an article I found asking for volunteers at Pentre Berw, I made contact and turned up. I was made to feel so welcome, despite my disability, that I stayed. I can honestly say it was one of the best decisions I ever made. All the volunteers and staff at GAT have been amazing, making sure that I can get me, my kneeling stool and other equipment on site safely.


Day 19

Here's some great aerial photography of our excavations at Dinas Dinlle hillfort, courtesy of Toby Driver and the CHERISH Project.

Day 20

4th August 2022

Well we’ve made a very interesting discovery regarding the walls of our roundhouse.

They’re not made entirely of stone!

It seems the roundhouse builders partially dug a circular hole (the roundhouse interior) down to the natural soil, then put in the inner facing stones around this hole, wedging the stones into place. Some of the material from the interior was then deposited behind the stones, helping hold up the inner facing.

Then outer facing stones were added, on the contemporary ground surface. The rest of the material from the interior was used to fill up the remaining space between the two faces, finished with a layer of stones on top.

What we have here is essentially a revetted earth bank with a stone capping.

Day 21

5th August 2022

Our final day at Dinas Dinlle hillfort.

Thanks to all our staff, our amazing volunteers and Bangor University students, all the school pupils who helped us with our work, Rhys Mwyn, Cadw, the National Trust, the CHERISH project, the BBC, Daily Post, Current Archaeology and to all the members of the public who have shown an interest in our work here.

Thanks too to the tenant farmer.




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