Martina’s Midden: Beach Clean results in Archaeological Discovery by a Citizen Scientist!

IT Sligo Applied Archaeology lecturer and MASC Project director @DrJamesBonsall reports on our first Citizen Science success

The MASC Project (Monitoring the Archaeology of Sligo’s Coastline) was initiated to increase awareness of coastal erosion and its impact on vulnerable archaeological sites. A key element of the project is to educate and encourage Citizen Scientists to report the discovery of (or damage to) archaeological sites due to erosion and storm-tide activity in coastal areas. The law in Ireland requires such discoveries to be reported to the Archaeological Survey of Ireland (ASI) – a fact that most members of the public are unaware. Last month, the MASC Project received its first report of a possible archaeological site by a Citizen Scientist (rather than a trained archaeologist). Martina Butler – a member of the public with no prior archaeological training – discovered a previously unknown Midden at Rosses Point, Co. Sligo, whilst carrying out an An Taisce Clean Coast Beach Clean. Last week, Martina’s discovery was confirmed by the ASI and officially placed on the Record of Monuments and Places (Ireland’s statutory list of all known archaeological monuments).

Midden, viewed from SW (O’Shaughnessy 2015). ‘Martina’s Midden’ at Rosses Point (RMP No. SL008-203). The site was reported to the MASC Project by Martina Butler, who informed the Archaeological Survey of Ireland. The midden was exposed on the beach due to strong tidal erosion. Image: Archaeological Survey of Ireland.

Martina Butler is the secretary of the North West Sea Kayaking Association (NWSKA), based in Sligo. Martina was keen for herself and the NWSKA  to get involved with the MASC Project after she met IT Sligo lecturer and project director Sam Moore, at a Clean Coasts Roadshow in Rosses Point, organised by Olivia Crossan, in March 2015. Speakers at the Roadshow shared their experiences of organizing some truly inspiring beach and coastal cleaning events all fueled by volunteers putting in a fantastic effort. Sam and I, on the other hand felt like interlopers, but we were kindly invited to talk about the MASC Project and introduced the audience to the notion of ‘ancient litter’, coastal erosion and vulnerable types of archaeological sites.

Just 8 weeks after the Roadshow, Martina had organised the NWSKA to carry out a Coast Care clean up on the beach at Rosses Point, where, among the litter and messages-in-a-bottle, they discovered something very different. “I was scanning the sand and rocks for litter when I noticed the distinct layer of shells” said Martina. “The chance that it might be a midden came into my head, particularly when I noticed that there were bits of possibly burnt stone embedded in the darker sand layer underneath the thin shell layer.” Martina had a feeling it might be a midden as she recognized its similarity to other examples she’d seen at Culleenamore beach. “I called over [NWSKA members] John and Eunan to see what they thought of the find and they agreed that it could be something significant also. We stayed for a short while looking about the site and we found more bits of burnt material. We also noticed some very recent campfire burning in the location which added some modern day burnt deposits onto the site unfortunately.”

The NWSKA discovered a thin layer of shells eroding out of a dune on Friday 15th May 2015, during the NWSKA Clean Coasts beach clean. Image: Martina Butler.

Martina was careful to take a number of photographs of the possible midden, but wasn’t sure if her discovery was important or not. “I noticed the shells there on Friday and thought that lots of other people would too, or that the MASC Project possibly already knew about the site or that it was a well known midden site.” The next day, Saturday 16th May, she emailed the MASC Project with her photographs and a description of what she found:

“This is possibly not a new find to you but I’m sending it on just in case! A small number of our members were doing our An Taisce Clean Coast clean up yesterday evening at Rosses Point and came across a thinish layer of oyster shell deposits to the northern end of the “First Beach” at the start of the rocky outcrop, in the small cove that has developed where the old concrete changing huts used to be.”

Armed with this information and Martina’s photographs, began our investigation. Firstly, the photographs certainly suggest that the feature looks like a midden. Helpfully, a number of the photographs featured NWSKA members next to the site as well, which was great for us as allowed us to get a sense of the size and scale of the site. We were also able to immediately examine the online RMP site records for Sligo and found that there were no known middens recorded at that location. That suggested Martina’s discovery might be a previously unrecorded monument, however there were some issues to deal with first before we could safely describe it as an ‘archaeological feature’.

Large deposits of shells can occur naturally – just look at the quantity of shells on the high tide mark the next time you walk down a beach – so an accumulation such as this might not mean the discovery is an archaeological feature, it could just have been a natural wash-in of shells that were buried by sand and subsequently eroded. The presence of burnt deposits was encouraging as this indicates the presence of a hearth / cooking site etc., BUT we already knew from Martina that modern campfires could also be responsible for the traces of burning.

Part of the midden, as photographed on 15th May 2015. Image: Martina Butler.

A careful examination of Martina’s photographs suggested the presence of small pieces of charcoal mixed up within the shell layer (not just on top of the shells, which might suggest more recent burning activity). Seeing charcoal mixed in with the shells is a very encouraging sign and suggests that people had been burning (possibly cooking?) and discarding the used (eaten) shellfish at the same time. In order to be sure that the site was an archaeological one, we needed to carry out an independent site visit. Within a few hours of Martina sending her email, Ciarán Davis – a local MASC Project volunteer and IT Sligo Applied Archaeology student – had found the site, taken more photographs, obtained an accurate GPS coordinate for its location. “The shells were quite concentrated in one area” said Ciarán, “well embedded oyster and periwinkle shell, there were no bones present, but several flecks of charcoal”.

A rapid assessment by the MASC Project on the 16th May 2015 confirmed Martina’s discovery as a Midden. Image: Ciarán Davis.

Thanks to the two reports, we now had enough information to fill out a Monument Report Form. The ASI receives a number of such Reports per month, which they then act upon by carrying out their own site visit – some Reports will confirm genuine archaeological features whilst others will turn out to be natural features. By verifying the presence of archaeological material firsthand, the MASC Project could assure the ASI that the Report was a genuine archaeological feature. The ASI logged the Report on Monday 18th May.

Four days later, ASI Archaeologist Jane O’Shaughnessy visited the site, took extensive measurements and recorded the deposits. Jane’s report, compiled and uploaded to the ASI’s online webviewer by the 26th May, was completed just 11 days after the site was first discovered by Martina and the NWSKA. The ASI now records Martina’s discovery as a Midden, officially designated as RMP No. SL008-203—-.

The Midden is located in a small cove that has recently been eroded. Image: Ciarán Davis.

Martina’s Midden at Rosses Point (RMP No. SL008-203—-, shown here in Red), is one of 91 middens in Co. Sligo (shown in Yellow). Image: Archaeological Survey of Ireland.

What is a Midden?

A ‘Midden’ is ‘a refuse heap, sometimes surviving as a layer or spread’ and they are typically comprised of shells, bones, charcoal and burnt stone (ASI 2015). They are, essentially, the piled up refuse generated from one or (more likely) several meals. Middens can tell archaeologists about the diet of those that created them and give an idea of their seasonal use (the time of year they were created can be determined based on the types of ‘seasonal’ shellfish found in the midden). Middens can date from the oldest known period of habitation in Ireland – the Mesolithic (c. 8000 BC – 4500 BC) – all the way through to the medieval period (5th-16th centuries AD).

The ASI currently includes 91 middens in the RMP for County Sligo and Martina’s Midden is the only one known at Rosses Point; the next closest examples are on nearby Oyster Island and Coney Island. Martina’s Midden is 6.5m in length, 1.2m at its widest point and varies between just 2cm and 10cm in thickness. The very thin layer of midden material could suggest that the site is a very temporary or short-term seasonal site, however it is also possible that what we see today is the final tapering edge of a much larger midden that may have been destroyed via erosion, or the tapering start of a midden, the rest of which might be preserved under the dune. The midden is lying on top of a stony subsoil and was covered by dune sands. The subsoil is not easily eroded and forms a good solid platform, whereas the dune sands were easily eroded by the tide or the wind. The adjacent dune sands are currently covered in marram grass – this is normally very good at stabilizing dunes and is often planted to protect vulnerable dune systems (such as at nearby Strandhill). However the positive effect of marram grass can be easily removed by people and animals continually walking over it.

Previous discoveries by the MASC Project (including middens, burnt mounds of stone and ancient peat shelves) were made by archaeologists – Martina is the first Citizen Scientist – a member of the public with no formal training in archaeological methods – to report a new monument to us. The midden could of course have turned out to be natural shell accumulation, or to have been a previously recorded monument, and those outcomes would still have validated the MASC Project aims (to raise awareness, educate and inform). As it happened, it was a previously undiscovered archaeological site found by a member of the public, which gives us reason to celebrate our first success!

NWSKA members participating in the Coast Care clean up at low tide, Friday 15th May 2015. L- R: John Lydon (NWSKA), 3 (anonymous) little beach walkers [who wanted to see what the message said in the bottle (“Plastic”!) that was also found that evening], Martina Butler (NWSKA) and Eunan McGlinchy (NWSKA).

Future Participation in the MASC Project

From Martina’s perspective, the experience is one which she is keen to pursue again. “I have been involved in organizing beach clean ups on behalf of our Sea Kayaking group before and because of that we had been invited to the Roadshow event in Sligo Yacht Club organised by Olivia Crossan of An Taisce Clean Coasts at which I heard about the MASC initiative for the first time”, said Martina. The NWSKA offers archaeologists a unique opportunity, she says “I thought that it would be a really worthwhile initiative for our organisation – North West Sea Kayaking Association – to get involved in as we paddle the coast of the North West, including many of the islands and other more remote parts, Thus we might spot newly exposed sites or artefacts in those areas where others might never be able to get to as easily and at a pace that makes it more possible to see more. NWSKA members were very supportive and we look forward to continuing to support the MASC Project initiative as it evolves in the future.”

Since her discovery, Martina has been helping the MASC Project to beta test a new user friendly online form (based on the ASI’s Monument Report Form) for members of the public to report new discoveries. As Martina herself has pointed out, a key question to ask those completing the form is “Would you have notified anybody / organisation of your discovery, if you had not been aware of the MASC Project?”, to which Martina readily admits “No”. Martina’s discovery (and its validation by the ASI) has been a wonderful outcome for the MASC Project. It has clearly demonstrated the benefit of educating local beach users – Citizen Scientists – about vulnerable archaeological features along our eroding coastline and how they can assist by informing the appropriate authorities.

If you’d like to help with the beta test of our new form ‘Report a Possible Archaeological Discovery to the MASC Project’, or to join the MASC Project volunteer network, please contact us.

Archaeological Survey of Ireland report on RMP No. SL008-203—-

O’Shaughnessy’s (2015) report on RMP No. SL008-203—- (Martina’s Midden) is available from the Archaeological Survey of Ireland and an edited version is reproduced below.

“This midden is overlain by the pale-coloured sands of the dunes which form a layer 0.9-1.6m high above the midden, but which rise to several meters in height as they extend to E in undulating, marram grass-covered hills. The midden overlies a layer (0.45-0.5m) of orange-brown stony subsoil which rests on bedrock. As a result of differential erosion, a narrow shelf (L c. 8m NW-SE; max. Wth 1.4m NE–SW) of the more weather-resistant stony subsoil protrudes from beneath the dune face. The midden is exposed on the surface of this shelf.

General location, viewed from the SE (O’Shaughnessy 2015). ‘Martina’s Midden’ at Rosses Point (RMP No. SL008-203), located in a small cove that has been eroded away. Image: Archaeological Survey of Ireland.
Midden viewed from S (O’Shaughnessy 2015). The thin spread of material lies on top of a stony subsoil and beneath a sand dune which has been partially eroded. Image: Archaeological Survey of Ireland.

The midden is evident as a dense, compact layer (L 6.5m NW–SE; max. D 0.1m) of oyster shells, which also incorporates a small quantity of periwinkles, stones and charcoal fragments. Due to age/weathering, the oyster shells are in a friable and shattered condition. The shell layer is more fully exposed in plan, and is thickest in depth, at its NW end (Wth 1.2m NE–SW; D 0.1m), but towards the SE the shell layer is visible only in section as a thin lens (D 0.002-0.004m). At its SE end, it is overlain by, or incorporated into, a layer (D c. 0.05-0.07m) of rusty orange-coloured sand exhibiting moderate charcoal flecking, with the pale coloured dune sand overlying this. However, at its NW end the pale-coloured dune sands appear to directly overlie the midden. The exposure of the midden appears to have occurred during the period 2014-2015 as a result of high tide and storm action (pers. comm. 18th May 2015: Dr. J. Bonsall, Sligo IT/Masc Project (Monitoring the Archaeology of Sligo’s Coastline)).”


ASI 2015. Class List Definitions – ‘Midden’. Archaeological Survey of Ireland. Available on [Accessed June 1st 2015].

O’Shaughnessy, J. 2015. SL008-203—- (Archaeological Survey of Ireland, Record Details) on, Compiled by Jane O’Shaughnessy, Posted 26 May 2015.

The MASC Project is on Twitter @MASC_CoastArch

Cite this article as: Bonsall, J. 2015. Martina’s Midden: Beach Clean results in Archaeological Discovery by a Citizen Scientist!. The MASC Project. [Published 1st June 2015].