Accident not intention: Llyn Cerrig Bach, Isle of Anglesey, Wales—site of an Iron Age shipwreck

The International Journal of Nautical Archaeology (2002) 31.1: 25–38 doi:10.1006/ijna.2002.1020

Accident not intention: Llyn Cerrig Bach, Isle of Anglesey, Wales—site of an Iron Age shipwreck Owain T. P. Roberts Penrallt, Penrhyd, Amlwch, Anglesey, LL68 9TN, UK The assemblage recovered fortuitously from Llyn Cerrig Bach in 1942 has been assumed without evidence to be the result of a Late Iron Age casting of votive offerings into that lake. The circumstances of its recovery and a consideration of the natural forces that have worked great changes to the coastline of south-west Anglesey suggest an alternative origin for the assemblage, that of its being the remains of cargo from a trading vessel lost about 50 BC.  2002 The Nautical Archaeology Society Key words: Llyn Cerrig Bach, votive, sand bars, dunes, fetch, prehistoric Irish Sea trade.

Introduction lyn Cerrig Bach, one of a trio of closely associated lakes in the north-west corner of the Isle of Anglesey in north Wales, was the source of a spectacular assemblage of Iron Age metalwork. Its presence in the lake has been attributed by archaeologists, after considerable agonizing, to ritual practices, noted elsewhere in Europe, of making votive offerings by casting items into the waters, perhaps over a long period of time. Aspects of the discovery and the evidence of widespread changes along that particular coastline in the vicinity of the site prompted the writer to consider whether the artefacts recovered were not part of a votive hoard but rather represented the remains of a cargo carried by a ship that was wrecked while on passage in the Irish Sea. The accepted interpretation for the presence of the artefacts in Llyn Cerrig Bach is that, in keeping with what are believed to be Iron Age Celtic beliefs, the lake had magical or mystical connections (Fox, 1946; Lynch, 1970; Savory, 1973; Macdonald & Young, 1995; Macdonald, 2000). These and other authors suggest or support the view that, over a long period, items, all with origins distant from Anglesey, were cast into the lake. The assemblage is deduced to be the result of votive offerings made from at least the beginning of the 2nd century BC to late in the 1st century AD. The identification as a votive deposit and the dating of all items has been based on comparison with other deposits and artefacts elsewhere. The

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view depends on the prior assumption of the existence of a lake at that time. It relies also on the Roman historian Tacitus’ writings, compounded from a mixture of hearsay and even earlier writings, to set a scene in order to propose an uncertain, long-standing, perhaps Druidical, sacrificial ceremony that could have centred on Llyn Cerrig Bach. However, much uncertainty has been shown by archaeologists when discussing the causes of the Llyn Cerrig Bach deposit as, for example: Any connection between the sacred pool of Llyn Cerrig Bach and the Druids is speculative but the link is attractive since the Druids of Anglesey . . . might well be responsible for gathering together such a varied and impressive collection . . . (Lynch, 1970: 277).

In his important book analysing prehistoric hoards, Richard Bradley’s silence with regard to Llyn Cerrig Bach is deafening. This, regarded as the largest and most important hoard from Late Iron Age Britain, he dismisses with a single passing reference where he mentions iron currency bars from the Thames, ‘and the remarkable water find from Llyn Cerrig Bach on Anglesey’ (Bradley, 1990: 173).

Discovery and interpretation Llyn Cerrig Bach, the lake of the small stones, had turned into a marsh over centuries (Fig. 1). In  2002 The Nautical Archaeology Society

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Figure 1. Map of Ynys Mon–Anglesey showing relief, drainage, and dunes. (Drawing: author)

1942, it was excavated for its peat by mechanically dragging a steel scoop across it many times. The action was performed at increasing depths until evidence that the lake bed was being dragged appeared as ‘thin and watery peat’ and peat ‘mixed with clay or sand’ (Fox, 1946:1). Coring in 1995 seemed to confirm this (Macdonald & Young 1995: 22). In 1942, the extracted peat was spread over the smooth top of a rock outcrop to its west, the edge of which drops as a vertical side to the lake’s bottom. When dry, it was spread by harrow to bind the sand of the dunes on which the RAF’s Valley airbase had been built. From this inauspicious beginning came to light the most important collection of Iron Age artefacts to be recovered in Wales and in Britain (Fig. 2). The account of the recovery, together with descriptions of all the finds, is to be found in subsequent archaeological publications (Fox, 1946; Lynch, 1970; Macdonald, 2000). The artefacts are displayed in Cardiff at the National Museum and Gallery. The intention is not to discuss them here, 26

except in so far as they are relevant to the process that caused their location in the lake. All artefacts were reported as being recovered from one tightly delineated area. This was established when Cyril Fox questioned the Resident Engineer, who had been present during the time that they were being picked out of the drying peat but some time after the reporting of the finds to him in Cardiff. No archaeologists were present at the time of their recovery from the lake. There was no doubt that the site of their recovery lay immediately below the vertical face of the rock used as the drying area. This rock has featured in interpretations, as it is regarded as the platform from which the offerings were cast during a period when infilling peat had not yet reduced the lake significantly (Fox, 1946: 1). On reading the various papers describing Llyn Cerrig Bach and its archaeological treasure, certain strands of inconclusiveness and an inability to explain convincingly the features of the site and its artefacts are seen to wind their way throughout

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the narratives, though all writers quite naturally feel the need to subscribe to the original theory that votive offerings are the only explanation for the presence of this unique assemblage in such a distant place. Sir Cyril Fox’s ‘Discussion’ of the origins of the assemblage shows the difficulty that he had, and others still have, in understanding its presence in Llyn Cerrig Bach: The Discussion on the . . . find has now reached a satisfactory conclusion, archaeologically speaking; but it is incomplete until the most obscure and intractable problem connected therewith, that is the source or nature of the economic strength which drew manufactured goods of high quality into the Island through so many generations, has been studied (Fox, 1946: 70).

The factors that continue to cause the greatest heart-searching among archaeologists may benefit by being examined from a different and pragmatic perspective.

Position of the votive offerings No items were found elsewhere in the lake according to eyewitnesses, but all were dredged from close to the vertical rock-face that plunges to the bottom of the lake. Offerings as heavy as chariots clearly would be dropped over the edge, but lighter items, like swords, spears, and daggers might have been expected to have been flung towards the middle. Instead, all artefacts are reported as being found in the one close area.

Relationship of the artefacts to Anglesey None of the artefacts have any archaeological connection, or are to be found in any possible context associated with Anglesey. Fox had suggested that the assemblage may represent booty captured over years of tribal fighting on the mainland fringes of the Island and then cast in as offerings to some deity or belief. Other suggestions are that it was the result of cultural ties with Ireland, or that the later dated items were the last despairing gestures of refugees from the Roman conquests (Fox, 1946: 70). The countryside of Anglesey is so uneven that it is generally agreed that the chariots were not used there and could only have been brought from elsewhere; it has been noted that chariots do not feature in Welsh campaigns (Lynch, 1970: 258). The chariots were recovered only as a collection

of metal fittings. These did not make complete sets for each chariot, although it has been calculated that the pieces of iron tyre may represent anything from 10 to 22 chariots. Only one complete iron tyre was recovered. The sources of similar chariot parts used to date and establish the possible origins of those from Llyn Cerrig Bach are listed in Table 1, and Table 2 shows the same information for the other artefacts recovered. It can be noted that parallels used for the dating of both the chariots and the other items almost all have their contexts in southern or south-western Britain and, in some cases, have a Continental origin. Fox showed the distribution of comparative sources as a series of maps for each item. Macdonald’s up-to-date discussion of the sources of the copper alloy artefacts is especially thorough (Macdonald, 2000). The origins of all the artefacts are outside Anglesey and, in many cases, very distant. That is all that may said about them with some certainty. Whether they were collected intentionally for deposition, for ritualistic or any other purposes, takes the discussion of their discovery into an unquantifiable and even fanciful area that nevertheless has needed to be explored in the search for a viable theory.

Organic materials Fox wrote, ‘As I myself saw, the mass of bones dredged up with the peat was considerable, only small samples, not expertly selected, reaching the Museum’ (Fox, 1946: 67). Organic material recovered included bones of oxen, sheep, a pig, and a dog. Bones for an indeterminate number of ponies were also present. Of course, most of the bones seen by Fox may have been the result of animals being trapped in the bog subsequently formed during historic times. However, three samples were recently radiocarbon-dated giving their ages as 207550, 224550, and 234550 BP (Hedges et al., 1998: 236). The earliest and the latest dates, if related to episodic deposition, would extend the dates generally accepted for the metalwork. The dating of the bones can be of use only if evidence for deposition and ritual activity is being sought fervently. No evidence of butchery has been noted on the recovered bones. They are thus not obvious ‘food offerings’, as identified by Janet Levy in ‘votive contexts’ (Levy, 1982). 27

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Two species of timber were recovered. One was a small fragment of ash within a spiral bronze fitting, possibly from a chariot. Ash was a favoured species for flexible structures. Ash was also found within the socket of a spearhead and as

a number of short pieces no more than 20 cm long. The other was hawthorn or cherry from within a yoke cap (Fox, 1946: 74, 86, 98). There were no reports of other timber surviving from the many chariots thought to have been sunk in the 29

NAUTICAL ARCHAEOLOGY, 31.1 Table 1. Sources of chariot parts used to date and establish the possible origins of chariots from Llyn Cerrig Bach (after Lynch, 1970 and Macdonald, 2000) Chariot item

Comparative sources

Chariot wheels (iron types) Nave rings Axle linch pins Embossed decorative squares and strips Yoke caps Terrets Horse bits Bronze spiral (around ash frame?)

Typical of different areas of Britain—undatable Read’s Cave, the Mendips Arra, Yorks, Stanwick, southern Britain Belgic type—southern Britain in Belgic context and Lydney La Te`ne—Battersea, Dorset, Brentford South-west Britain Irish (1), Breden Hill (Glos), Glastonbury, Continent Armentiers, northern France for iron type

Table 2. Sources of other artefacts from Llyn Cerrig Bach (after Lynch, 1970 and Macdonald, 2000) Artefact Iron currency bars Gang chains for slaves Eleven swords Daggers Spearheads Shield boss Cauldrons Broken trumpet Tools—tongs, sickles

Comparative sources Somerset, Wessex, Datchet (Bucks) Identified as of Belgic origin All southern origin, Belgic characteristics, continental stamping (2) Somerset Typical La Te`ne from Britain and the Continent Possibly north Wales but patterned like sword scabbard from La Te`ne itself Battersea type (1), other of ‘Spettisbury type’ Irish From the earliest Iron Age context generally

lake, but with no archaeologist on site, the chance was lost to observe any ahead of destruction by drag-line and harrow.

Dating of the components Dating has been performed by identifying each Llyn Cerrig Bach artefact with parallels from other sites where phases can be estimated with certainty. This has permitted an estimation of the beginning and end of the period during which the Llyn Cerrig Bach artefacts were likely to have been produced and used (Fox, 1946; Lynch, 1970; Macdonald, 2000). In Table 3, the date range for each artefact is shown graphically. The long periods indicated for some items merely show only that they were in use or being produced at any one time between those dates. The earliest dates for some artefacts and the latest for others encourage support for the accepted view that, ‘the Llyn Cerrig Bach assemblage represents material deposited episodically over a period of potentially several centuries’ (Macdonald, 2000: 235), a con30

clusion of long standing (Fox, 1946: 70; Lynch, 1970: 250; Savory, 1973: 25). However, as may be seen for those artefacts with a date range of more than 100 years, a date in common of about 50 BC emerges. This is not incompatible with those artefacts with the longest range. Inclusion of the closest-dated items reduces their common mean date to about 46 BC. Deposition of all the artefacts, whether or not as votive offerings, could thus have been one event.

The paradox The tight grouping of the artefacts in a small area before salvage; their distant origins; the almost total lack of timber; the preservation of bone; and, finally, the mean date of deposition, despite the possible date range of some, constitute the problems that have made it difficult to understand the site within the terms of land archaeology. From the perspective of the nautical archaeologist, most of these aspects are the usual attributes of an ancient wreck-site.

O. T. P. ROBERTS: ACCIDENT NOT INTENTION Table 3. Llyn Cerrig Bach—50 BC as a date in common for the assemblage (after Lynch, 1970 and Macdonald, 2000)

- - - dated within the period;

no definite date possible.

Some attributes of ancient wrecks Loaded ships that sink nearly intact and away from the damaging effects of waves show a close distribution of cargo about the wreck-site. Amphora wrecks in the Mediterranean Sea are obvious examples (Pomey, 1976). However, close to Anglesey in the Menai Straits lies a Late Medieval wreck with its cargo of slates still tightly packed after about 400 years, though little of the hull survives (Jones, 1978). The Mary Rose is an example of a wreck holding a wide range of artefacts of a variety of materials that have stayed together because of the survival of much of the hull (Rule, 1983). Where a hull is almost completely destroyed owing to wave action in shallow water, the scatter of artefacts is usually extensive, as in Spanish Armada wreckage found on the west Irish coast (Martin, 1979). Where an open boat, perhaps similar to the Dover Bronze Age Boat (Parfitt, 1993), has filled and capsized, perhaps with enough residual buoyancy not to sink, there can be a close scatter of the densest items of cargo, as at Langdon Bay. This site of a Bronze

Age wreck in 8–12 m of water was identified by the scrap bronze items and miscasts recovered from fissures in the chalk seabed, but without the presence of any boat wreckage (Muckelroy, 1980). It is not unusual for items found on a wreck-site to have widely differing ages and still have current practical value. For example, in the RomanoCeltic ship excavated at St Peter Port in Guernsey, 80 coins were found. One group spanned the 2nd century dating from AD 117 to 200 and showed much use. The second group dated from the end of the 3rd century (Rule, 1990: 55). This is comparable with the period of time represented by the maximum date ranges of the Llyn Cerrig Bach objects.

Route indications from cargo details What route Pytheas followed in his exploration is a matter of guesswork, but from Cornwall we can suppose that he travelled northwards along the west coast in a series of short-haul voyages stopping off from place to place. A likely itinerary would have 31

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included south-west Wales, then along St George’s Channel to the Lleyn Peninsula and Anglesey before making for the Isle of Man (Cunliffe, 2001: 99).

The composition of a cargo reflects the area from which a ship may have sailed. A ship collecting a cargo somewhere in, say, the Bristol Channel or the Severn Estuary would have items aboard from south-west and southern Britain, perhaps even from the Continent. Ports within the Bristol Channel would have been entrepoˆts for goods being traded with the western fringes of the British Isles (Fox & Hyde, 1939: 387–9). As noted earlier, a cargo may well show a broad date span, and because of the need to amass a viable commercial cargo, its origins may also reflect a wide hinterland for its manufacture or intermediate trading. Such features may also be recognized in a votive deposit precisely because of the parallel needs to collect and source offerings, though motivated by opposing demands (Bradley, 1990: 26). The difference is that the former represents a group of artefacts brought together at one time, whereas the gathering or deposition of the latter may be spread over an indefinite period. Clearly, other factors need to be examined to avoid confusing the indicators used to identify episodic votive offerings with the evidence of shipwreck cargo, a single-date event, whether in the sea, in a river, or cast upon a strand.

Could Llyn Cerrig Bach have been an arm of the sea? In order to understand the link of Llyn Cerrig Bach with the sea, a starting-point must be consideration of theories of sea-level changes at about the end of the 1st millennium BC. As it happens, Anglesey has been at the pivot of isostatic adjustment for some time, with land to the north rising and to the south subsiding; as a result, it has been affected very little during that period (Devoy, 1990; Lambeck, 1995). More relevant and recent effects that need to be considered are linked to dynamic erosion and deposition mechanisms occurring along the south-west coast of Anglesey and common in the Irish Sea. Coastlines are not static boundaries and are capable of radical change within an historical period. A dramatic illustration is provided by Harlech Castle, built on a bluff at the edge of Cardigan Bay towards the end of the 13th century by the invading Normans. It was provided with a water-gate for entry and retreat by sea. The castle 32

now lies over half a mile (0.9 km) from the sea owing to a change in the shoreline near Harlech. This followed the growth of a bar 3 miles (4.8 km) long across the mouth of the Afon Dwyryd, behind which was created the flat coastal strip out of material carried over the bar by wave action towards each high-water period. Alluvial infill from the blocked rivers added to the creation of marsh land. On-shore winds blew sand off the bar on to this marsh land whenever it was uncovered by the tide. The dunes thus built are now a major feature of Morfa Harlech (Horrocks, 1953: 139– 140).

Early surveys of the dunes Tywyn Trewan and the beach Traeth Cymyran The earliest chart showing part of Anglesey was drawn by Capt. Grenville Collins in 1693. Apart from an inaccurate coastline and what may be the beach, Traeth Cymyran, and the river, Afon Crigyll, it shows no other detail shorewards. Lewis Morris, the outstanding chart surveyor to the Admiralty in the early 18th century was disdainful of Collins’ surveying skills (Budenburg, 1987). Recently, Anglesey Archives obtained a facsimile set of charts by Lewis Morris, Cambria’s Coasting Pilot. These had been carefully stored for over 200 years by the Admiralty but never published because of postponement caused by the beginning of another war with France in 1740 (Callender, 1924: 146). Lewis Morris’ chart of the entrance to Cymyran Straits shows an accurate coastline and a beach backed, as now, by dunes. A prominent mark, a large building upon a rock, is noted on the chart as an aid to pilotage. It still exists. Unfortunately, the extent of the dunes did not interest him, since they would not contribute to the value of the chart. The first OS Map of this part of Anglesey, Sheet 78, published in 1840 (but surveyed by about 1820) and early 20th-century maps at a scale of 6 inches to one mile (OSM 1901) show that the area of dunes, Tywyn Trewan, between the marshy Llyn Cerrig Bach and the sea is over one mile (1·6 km) wide, extending to a width of 1·5 miles (2·4 km) a little further along the beaches of Traeth Cymyran and its extension, Traeth Crigyll. Afon Crigyll is shown with a wide-sweeping meander to the west in an area now covered by more dunes. The long, narrow, steeply sloping beach is the boundary between the dunes and the sea.

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Research on the south-west coast Dr A. H. Robinson has studied the development of the south-west coast of Anglesey over many years with special reference to the dune development in four bays along that coast (Robinson, 1980: 37–38). Figure 3 shows the orientation of the beaches to the prevailing winds and the shoreline orthogonal of the dominant waves approaching them. One of these, Aberffraw, was once the wide estuary of the river, Afon Ffraw, before the establishment of a bay-head beach or bar and

the growth of the dunes that now fill it and have dammed in the lagoon, Llyn Coron, at its landward end. Here, there is a depth of 5 m. Robinson states that it is likely that the lakes behind Tywyn Trewan, including Llyn Cerrig Bach, are the result of a similar blockage by sand rather than being hollows in glacial drift (Robinson, 1980: 58). Traeth Cymyran links two rock-bound headlands whose ridges go inland to the north-east. With Traeth Crigyll, it faces the prevailing wind from the south-west, which blows at at least Force 7 for 21 days each winter. However, summer gales 33

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are more effective in moving sand, since, in that season, it tends to be drier and hence easier to dislodge (Robinson, 1980: 53). Before the growth of the linking bar or bay-head beach and the dunes, there would have been, as at Aberffraw, an ancient bay between the headlands over 2 miles (1·2 km) wide with a rocky coastline one to two miles (1·6–3·2 km) further inshore. The coastline would have encompassed the rocks at the edge and in the vicinity of the present-day Llyn Cerrig Bach in the ancient Cymyran Bay’s north-east corner, many of these rocks becoming islets from half flood twice daily. One of these is the so-called rock platform from which the Llyn Cerrig Bach hoard is said to have been cast. At the ancient bay’s southern edge, a river, Afon Crigyll, enters the sea, and at its northern limit lies the mouth of the sandy Cymyran Straits. Before construction across the Cymyran Straits of the road bridge, and later the railway embankment in the mid 19th century, an unimpeded ebb tide flowing south from Holyhead Bay would have reinforced the strong ebb tide gushing south out of the straits and into the coastal ebb tide flowing south-east across the ancient bay’s opening. At least two lines of outlying reefs once protruded in places through the dunes (OSM 1901), and their modern seaward remains are prominent beyond the beach. Consideration of the geology suggests it is probable that these once extended all the way to the old shore and split the ancient bay into three minor, parallel strips. These and the bay’s headlands are in keeping with the general landscape of Anglesey, which consists of gentle ridges separated by wide, low-lying hollows aligned parallel to the Menai Straits and in line with the southwesterly prevailing winds. More especially, on the south-west coast, the ridges terminate as rocky headlands petering out into rocky islets seawards, and the low ground between forms major natural drainage ending as bays now blocked by marshes and dunes (Robinson, 1980: 38–39). Probably, as at Harlech and at Aberffraw, at least one major bar was thrown up, which linked the headlands of the ancient Cymyran Bay. This was perhaps due to an exceptional south-westerly storm, a major single or catastrophic event during the latter end of the last millennium BC (Devoy, 1990: 19–20). South-westerly winds, that is about 28% of all winds affecting Anglesey on this part of the coast, have an uninterrupted fetch that extends directly into the Atlantic Ocean (Irish Coast Pilot, 1985). The offshore zone was the most likely source of supply for the 34

accumulating beach sediment that would have been washed ashore by the dominant wave pattern shown in Figure 2. The sediment would be primarily glacial in origin, representing the outwash deposits of the ice sheet that had covered Anglesey (Robinson, 1980: 41). Behind the sand bar, a large lagoon would appear as the spring tides receded. A similar major event at another distant time, owing to northerly winds, established a large, permanent lagoon on the north Anglesey coast at Cemlyn Bay behind a wide, stony storm beach. Lacking the pressure of frequent on-shore winds and the fine material needed for beach and dune building, the situation seemed to stagnate. In contrast, only two years ago, the Daily Post on 10 July reported that Trearddur Bay had sustained a reduction of 1·2 m in the height of its wide sandy beach within a few weeks. This bay is a little to the north of Cymyran beach and faces the same prevailing winds, which, at other times during gales, blow copious quantities of sand off the beach and over the roads in the immediate area. At Cymyran, the new lagoon would never drain much below the level of the sand bar, and the rivers are too small to have breached it. During spring tides, the bar would be covered and make the lagoon accessible to more material being carried in by wave action, thus initiating and continuing the process of turning the lagoon into saltmarsh upon which the dunes could grow (Holmes, 1961: 300, 304–305). A combination of wave action bringing sand infill into the lagoon at high water and wind blown sand from the bar at low water would begin the development of the dunes. With the growth of the dunes, the major cause of the infill of the lagoon towards its landward fringes would be wind-blown sand. The three new lakes, Llyn Cerrig Bach, Llyn Dinam, and Llyn Penrhyn, which once would have been bays of the lagoon, are part of the drainage system for the hinterland and receive water and silt from a network of streams. By then, the water in the lagoon would tend to be brackish. Peat would have started to be deposited from the reed beds developing in isolated remnants of the lagoon as in the area around the present Llyn Cerrig Bach, thus separating the three lakes. In time, Llyn Cerrig Bach was infilled with peat. The dunes, over 9 m high today when measured off the beach, continued to encroach landward and, by 1901, were closing in on the peat-filled and muchreduced area that once was Llyn Cerrig Bach.

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Recently, in the vicinity of Llyn Cerrig Bach, coring was undertaken to a depth of over 5 m by an undergraduate of the School of Ocean Sciences, University of Wales, Bangor. The upper peaty layer (technically, an organic mass because it is composed of organic detritus and silt), lay 1·7 m below the water surface. It was nearly 2 m thick, showing traces of blown sand and silty clay, both random and in a few, very thin layers. Its organic mass varied in its composition from 65% organic detritus at the surface to 30% near the base from where the organic content faded off to nothing above a layer of blown sand 25 cm thick. The lower values above this boundary might indicate the slow recovery of aquatic organic growth following the infertility of the 25 cm layer of sand. Beneath this sand layer, the organic mass has a higher composition of silts, organic detritus accounting for only 10–15% of the contents, then dwindling between the 4.5 m point and the maximum core depth of 5.2 m, to less than 3%. This may be explained as being a result of the presence of sea water when Llyn Cerrig Bach was still tidal. No dating of the pollen, which was recorded and identified throughout the length of the core, has been made (Cavan, 1998). However, this writer considers that the 25 cm layer of sand provides for the Llyn Cerrig Bach area an important terminus post quem of 1331, since it is evidence of the great storm that in that year destroyed with a blanket of sand much of the farmland of nearby Newborough, described below. There is nothing else in the core that compares even remotely with this horizon. Llyn Traffwll is another lake created by the dunes of Tywyn Trewan (Robinson, 1980: 58). It is separated by one of the ridges of rock that are a feature of this area and drains into Afon Crigyll, which flows through an extensive salt-marsh-andsand-dune hinterland before meandering into the sea at one end of Cymyran beach. Just along the coast is Llyn Maelog, separated from the dunes of Tywyn Trewan by the low headland on which lies the village of Rhosneigr. This lake is also the result of the enclosure of a separate bay by sand blown inland from Traeth Llydan. Dune development along this coast of Anglesey was recorded as a major feature of the Dark Ages. In at least two other bays, it occurred on a scale even greater than that being suggested for the dunes at Tywyn Trewan. A short distance down the coast, on the 5 sq. miles (13 sq. km) of dunes at Newborough, it is calculated that dunes may have advanced an average of 9·4 ft (2·7 m) per

year, so that the inner or oldest ridge of the Newborough dunes probably began on the 14thcentury coastline and moved to its present situation 6,200 ft (1890 m) inland of the present shoreline in the intervening 662 years (Robinson, 1980: 55). When a marshland platform has to be built ahead of that sequence, as at Morfa Harlech, then the advance of dunes during a similar period may be less. This is not necessarily continuous and gradual but may be due to major advances in tremendous storm conditions, as on a Newborough farm in 1331 when it was recorded that 186 acres (75 ha) were destroyed for ever by the inflow of blown sand (Robinson, 1980: 55). Across the Irish Sea, it is recorded that Howth was an island until 1479, but it quickly became a peninsula when drifting sand filled the gap of over a mile to create flat land barely above sea level (Hulbert-Powell, 1949). With south-westerly winds and dominant waves acting directly on Traeth Cymyran, perhaps Tywyn Trewan was built up intermittently over about 2,000 years. As noted earlier, the dune front had advanced so far by 1901 that it was beginning to encroach on the marsh area that had been Llyn Cerrig Bach and those other lakes blocked off at the original landward fringes of the old Cymyran bay. That the dunes did not do so was due to the intervention of the RAF, which consolidated them with the construction of an airfield. It was this activity that led to the recovery of the Llyn Cerrig Bach assemblage.

Soundings at Llyn Cerrig Bach Fox stated the depth of Llyn Cerrig Bach to be about 20 ft (Fox, 1946: 44), this being 6 m, or 0·2 m below OD (ordnance datum; Macdonald & Young, 1995: 22). This compares with the only other bathymetric survey made, that of Llyn Traffwll, with a depth of 19 ft (5·8 m) (Robinson, 1980: 58). The surface of Llyn Cerrig Bach was at 5·8 m OD. Before the probable creation of the sand bar and during a mean high water springtide range of 4·88 m, the bottom of the present lake, when it was a tidal channel, would have dried out in ancient times, during the latter half of the tidal range. The establishing of a storm-built sand bar, barely covered at high water neaps and the subsequent lagoon, would ensure a constant depth of approximately 2 m at the steep rock face, against which the artefacts were found. A sand bar and its lagoon at Cymyran would exist almost 35

NAUTICAL ARCHAEOLOGY, 31.1

continuously during a period of neap tides, perhaps for some centuries, the bar only disappearing beneath the sea during spring tides. In southwesterly storm conditions, the bar would be swept by surf and, during spring tides, would disappear beneath the waves racing across the lagoon. Any ship unable to avoid such a lee shore would be lucky to survive being swept over the sand bar into the lagoon at high water and would then be in danger of being dashed against the rocks of the old shore.

The last voyage Clearly, with such a scenario for the major changes that have taken place on that part of the Anglesey coast, it follows that a ship carrying the Llyn Cerrig Bach hoard would have arrived against the vertical rock face, after the major catastrophic storm event that established the bar, but long before dune development had commenced. The retention of deep water in the lagoon would conceal the sunken wreckage from salvors. One may imagine such a ship setting out from, say, the Bristol Channel in the early summer of, perhaps, 45 BC intending to trade somewhere on the east Irish coast as she had on previous occasions, or perhaps even sailing for the Cymyran Straits, a well-known safe haven (Fox & Hyde, 1939: 387–389). Her cargo of either knocked-down chariots or spare wheels, and perhaps including scrap metal (many of the items recovered showed wear from long use), was to be converted into a return cargo, including slaves for which the gang-chains were to be used. As usual, the crew were armed for their own defence. While on passage, a near gale, Force 7, say 30 knots from the south-west, overtook them, and in barely survivable conditions for an undecked vessel, she was driven up the Irish Sea towards Anglesey, in the direction of the bar across the ancient Cymyran Bay. High water and wind-generated seas up to 5 m high (Watts, 1981: 811) breaking in the shallowing waters carried the ship, by now in a sinking condition, nearly swamped and unstable, over the bar into somewhat quieter waters. There, the south-westerly gale still drove her towards the rocks in the north-east corner of the bay. Bumping hard against a vertical rock face was the final nudge needed to precipitate her capsize. Relieved of her heavy cargo, which sank quickly in nearly 3 m of water, she drifted away upside down to break up against another rock 36

platform some 50 m further on, which has been identified recently (Macdonald & Young, 1995: 23). Perhaps her exhausted crew did not survive. Her cargo remained undiscovered on the sea floor against the vertical side of the rock. Even at low tide, there was still over 2 m depth of water at her wreck-site. Flotsam would come ashore much farther along the shore. But for the presence of a surfable off-shore bar enclosing a slow-draining lagoon, she would have been dashed to pieces in the high energy zone of the beach and amongst the rocks, her cargo scattered far and wide. As it was, over many centuries, the salt-water lagoon was filled in slowly by wave and wind action. The growth of the bar coupled with widespread dune development finally sealed it off. The residual lakes by the rocks turned brackish, and reed beds soon encroached. The contents of the wreck, long reduced to its metal parts, was covered by the reeds and peat, seemingly forever. The pristine condition of the copper alloy artefacts, despite early long immersion in sea water is due probably to the subsequent, far longer immersion in lacustrine water. The usual destructive chlorides absorbed from seawater seem to have been removed entirely, dissolved out in a natural process of conservation (Robinson, 1981: 26–28).

What kind of ship? It has always been realized that some items may still be hidden in Llyn Cerrig Bach because of the haphazard retrieval from the spread out peat, but the amount not recovered is regarded as small. Therefore, if the items derive from a shipwreck, then their combined weight as cargo, with allowances for what may be missing, can be calculated. In attempting this, the weight of each item has been calculated from the published dimensions and the specific gravity of the material. Apart from chariots and wheels (which, for this calculation, are assumed to be complete), the totals were increased by two-thirds as an estimate of their cargo weight. A single chariot was calculated at about 260 kg, mainly because of its timber work (Lynch, 1970: 264). Four chariots were assumed to be cargo plus ten spare wheels with tyres and naves. If an allowance for six men with food and equipment is added to the manifest, the total is just under 4 tonnes. This is the weight of cargo that the 3rd-century AD Romano-Celtic boat from Barland’s Farm, South Wales, could carry in comparative safety. Measuring originally 11·4 m

O. T. P. ROBERTS: ACCIDENT NOT INTENTION

in length, she would have been capable of trading across the Irish Sea under moderate weather conditions (McGrail & Roberts, 1999: 141–142). In the absence of other ship-types in the archaeological record, the Barland’s Farm Boat may be regarded as a development of a type of vessel in use at the end of the last millennium BC.

Conclusion Previous reports and publications featuring the Llyn Cerrig Bach assemblage have remained constant to the original theory that it is a collection representing the results of years of religiously inspired votive offerings. Considerable academic endeavour has established links for the artefacts with similar places in Britain and on the Continent, places where the evidence of the practice of placing offerings in lakes and rivers seems indisputable. Yet, the evidence from Llyn Cerrig Bach still has caused doubt to appear. To quote Frances Lynch, a greatly respected archaeologist and expert in Anglesey’s prehistoric past, when discussing the iron currency bars, their presence at Llyn Cerrig Bach implies a considerable journey beyond their areas of normal distribution which, for both classes, lay in the south of England. The same may be said of a great many fine things from Llyn Cerrig Bach . . . for reasons which we cannot fully understand, a small lake in Anglesey received rich offerings from distant people for a period of over one hundred and fifty years (Lynch, 1970: 275).

The currency bars from Llyn Cerrig Bach can be linked with the presence of blacksmith’s tongs as being needed for trade or the practical and mundane purposes of smith work in connection with the voyage. It limits the usefulness of currency bars as indicators of commercial activity if their presence in hoards is used as an indicator solely of a votive offering assemblage (Bradley, 1990: 172). The alternative interpretation offered in this paper for the source of the assemblage is based on a different understanding of those aspects that have caused such difficulties in past discussions. Only in its precise chronology is the change to the coastline at Traeth Cymyran conjectural. It is based on well-known historical sequences in the region and can explain most, if not all, of the modern-day features found. The voyage hypothesized would be typical of commercial activity found in the Irish Sea for hundreds, if not

thousands, of years prior to that event (Fox & Hyde, 1939; Davey, 1999; Cunliffe, 2001). Being blown along out of control in a storm until driven on to a lee shore has been a hazard since humans took to the sea and is attested in historic times. For example, an unidentified wreck was discovered in 1978 off Harlech and named after the bronze bell, dated 1677, found with cannon and a cargo of Carrara marble. Historical research suggested that she had been on passage for London from the Mediterranean with marble destined for St Paul’s Cathedral. This was recently confirmed when the wreck was noted to be marked as Genoese and dated 1702, on one of the Lewis Morris charts, which, as mentioned above, had lain hidden. She seems to have underestimated the distance run before a gale, passed the entrance to the English Channel, and raced north up the Irish Sea, unaware of her position until stranded on the Welsh coast (Jones & Illesley, 1980: 157–158). Could this suggest another source much further south of the Bristol Channel for the origins of the Iron-Age cargo lost in Cymyran Bay? As a later example, in 1883, the well-found barque, Norman Court, running north in poor visibility before a gale in the Irish Sea on the final leg of a passage from Java to Greenock, became embayed in Carnarfon Bay and struck the rocks off Traeth Cymyran. A course just 10 miles (16 km) further to the west would have kept her clear of the murky Anglesey coastline (Parry, 1969: 102–103). The maritime interpretation put forward here as the source of the assemblage stretches credulity less than the picture of vast wealth, collected from great distances for over 200 years, being dropped periodically over the edge of a cliff as part of a hypothetical ritual in the name of an unknown deity. There is a real possibility that the artefacts recovered from Llyn Cerrig Bach represent the cargo from an Iron-Age ship, providing a rare insight into maritime trade. The evidence, real and circumstantial, points to an ancient shipwreck in the late Iron Age.

Acknowledgements The author wishes to thank Drs James Scoarse and David Jenkins, School of Ocean Sciences, University of Wales, Bangor for discussing aspects of this paper; also Mr Nigel Bannerman, Llandudno, a keen and knowledgeable local 37

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coastline historian, for his generosity in supplying information from his files. The author is indebted to Dr Philip Macdonald, National Museum & Gallery, Cardiff for an inspirational lecture some years ago, followed by correspondence, which

created an interest in the Llyn Cerrig Bach hoard such that the problems of its origins became like the grain of sand in an oyster with the results offered in this paper.

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