archaeologia cambrensis

ARCHAEOLOGIA CAMBRENSIS Cylchgrawn Cymdeithas Hynafiaethau Cymru Journal of the Cambrian Archaeological Association VOLUME 163 (2014)

Cymdeithas Hynafiaethau Cymru Cambrian Archaeological Association 2015

Cymdeithas Hynafiaethau Cymru Cambrian Archaeological Association

Established 1846 Registered Charity No. 216249 WEBSITE For further details of the Association and its activities visit our website: http://www.cambrians.org.uk EDITOR Material offered for publication should be sent to the Editor: W. J. Britnell, 75 Abbey Foregate, Shrewsbury, SY21 6BE. Tel. 01743 369724, email [email protected] REVIEWS EDITOR Books for review should be sent to the Reviews Editor: Dr R. J. Silvester, CPAT, 41 Broad Street, Welshpool, Powys, SY21 7RR. Tel. 01938 552035, email [email protected] PERIODICAL LITERATURE Periodical Literature on Wales is compiled by: J. E. Britnell, 75 Abbey Foregate, Shrewsbury, SY21 6BE. Tel. 01743 369724, email [email protected] GENERAL SECRETARY General enquiries and enquiries regarding grants and awards should be addressed to the current General Secretary: Mrs Heather James, Braemar, Llangunnor Road, Carmarthen. Tel. 01267 231793, email [email protected] MEMBERSHIP SECRETARY Enquiries about membership and subscriptions and publications for sale should be addressed to the current Membership Secretary: Frances Lynch Llewellyn, Halfway House, Pontypandy, Bangor, Gwynedd, LL57 3DG. Tel. 01248 364865 © The Cambrian Archaeological Association and individual authors, 2015 ISSN 0306-6924 Typeset and Printed in Great Britain by 4word Ltd, Bristol

Archaeologia Cambrensis 163 (2014), 99–131

Snail Cave rock shelter, North Wales: a new prehistoric site By George Smith1 and Elizabeth A. Walker2 with contributions by Julia Best,3 David Jenkins,4 Frances Lynch,5 Richard Madgwick,6 Rosalind McKenna,7 and Ben Rowson8

An evaluation of Snail Cave, a rock shelter on the eastern side of the Great Orme in 2011 revealed a sequence of deposits, which despite some disturbance by burrowing animals, showed evidence of Mesolithic activity in the late ninth and early eighth millennia BC, Neolithic activity in the fourth millennium, and possible Beaker and Bronze Age activity in the third to second millennium BC. The Later Mesolithic activity, possibly representing seasonal use as a shelter, is associated with a small assemblage of lithic artefacts and a perforated cowrie shell bead. Evidence for the exploitation of marine, intertidal and terrestrial resources is indicated by the presence of shellfish, fish bones, hazel nuts, and the bones of wader birds. The evidence for this new prehistoric site is discussed in the light of other evidence of early prehistoric activity in the locality and further afield in North Wales.

INTRODUCTION In 2010, David Chapman9 discovered eroding surface deposits within a large, but shallow, rock shelter close to Pentrwyn headland on the east side of the Great Orme, Conwy (formerly Caernarfonshire) a natural headland extending north into Liverpool Bay (Fig. 1). The rock shelter, named Snail Cave, had a layer of marine shells exposed on the surface and several small flint blades were collected from the eroding deposits. The site was visited by Elizabeth Walker who arranged for the shells to be identified by Ben Rowson at the National Museum Wales. Although most were local terrestrial or marine intertidal species they included a perforated cowrie shell bead. This, with the worked flint, suggested a new prehistoric occupation site. A small evaluation excavation, funded by Cadw, was carried out during June 2011 to assess the potential of the site. This work produced an assemblage of lithic material of Later Mesolithic type together with marine and terrestrial mollusca, mammal and bird bone and palaeobotanical evidence. The rock shelter lies within a near vertical cliff face on the east side of the Great Orme at SH 7807 8370, at a height of c. 70m above Ordnance Datum (Fig. 2). It consists of a longitudinal overhang about 25m long and 2m deep, with a fairly level floor (Fig. 3). At the east side the shelter has a steep slope which is a stable and grassed-over former scree slope. This scree and the shelter probably result from differential weathering of the cliff face under extreme glacial or periglacial conditions. Smaller longitudinal cavities occur higher up the cliff face; these are protected as nesting sites for fulmars. The Great Orme is a prominent limestone headland with a maximum height of 220m above Ordnance Datum and with steep cliffs on all sides. It is joined to the mainland by a narrow isthmus only just above sea level which, before modern drainage and improvement was marshland. It has been suggested that the postglacial sea-level rose to a maximum somewhat above that of the present day in the Neolithic period, before receding again and that the Great Orme was an island at that time (Whittow 1965). The many caves on the Great Orme have been used extensively by humans for different purposes at various times. The 99

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Fig. 1.  Mesolithic flint and chert finds in North Wales. 1 Rhuddlan; 2 Trwyn Du; 3 Penmon; 4 Pencilan; 5 Garreg Hylldrem; 6 Bardsey; 7 Porth Ruffydd; 8 Bedd Branwen; 9 Newborough Warren; 10 Roman Bridge, Lledr Valley; 11 Brenig; 12 Llyn Aled Isaf; 13 Splash Point, Rhyl; 14 Prestatyn; 15 Gop Cave; 16 Tandderwen; 17 Pontnewydd Cave; 18 Lynx Cave. © Gwynedd Archaeological Trust. caves are unusual in North Wales as rare residues of early human activity with good preservation of human and mammal skeletal material as well as stone tools. The cave sites known on the Orme comprise Upper Kendrick’s Cave, Ogof Tudno (St Tudno’s Cave) and Lloches yr Afr (‘goat shelter’). Kendrick’s Cave is situated in the southern scarp and as well as Late Upper Palaeolithic artefacts (Sieveking 1960; Green and Walker 1991) has produced Neolithic, Beaker and Romano-British objects. Ogof Tudno, also known as Badger Cave, lies further north on the east side of the Orme and has produced bones of domestic and wild animals as well as marine shells, indicative of human activity, although there are no prehistoric finds from here. Lloches yr Afr lies close to Snail Cave, on the north side of the nearby Pentrwyn headland and was truncated when the Marine Drive road was constructed about 1877 and has produced a Late Glacial faunal assemblage as well as finds of Mesolithic and probable Neolithic date (Davies 1989, 95–99).



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Fig. 2.  Topographic location of Snail Cave in relation to the changing coastline. © Gwynedd Archaeological Trust. EXCAVATION RESULTS By George Smith A trench 3m by 1m was excavated by hand across the centre of the rock shelter at the point where the surface spread of marine shells was identified (Fig. 4). The trench extended from the back wall of the shelter, against the rock face, to the forward scarp edge, just beyond the drip-line of the shelter, where the grassed-over scree slope began. All excavated material was wet-sieved through 10mm and 2.5mm mesh on site and was hand-sorted. Separate bulk soil samples were taken for flotation for palaeoenvironmental

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Fig. 3.  The rock shelter, from the south. Scales 1m. © Gwynedd Archaeological Trust. analysis with the flotation component retained for analysis. After excavation the trench was lined with a geotextile membrane, backfilled and the surface of the whole shelter was protected by a layer of limestone chippings. The deposits in the rear of the shelter were mainly of unconsolidated scree and silt that merged downwards with little evidence of stable horizons. The deposits in the front half of the shelter were more differentiated and discrete but were affected by animal burrows. Marked horizons within the deposits that might represent earlier occupation surfaces were absent and it is clear that all the deposits must have been infiltrated by small mammals between loose scree. A more substantial burrow had penetrated the front half of the deposits resulting in some mixing of artefacts both by residuality and by movement downwards. There was also some evidence for the intrusion of more recent, even modern material into deposits. The deposits were, however, assigned to five horizons based on changes in matrix and evident stratigraphy, as discussed below (Table 1). Horizon 1 The surface layers were exposed and although compacted, were subject to erosion and trampling. A cowrie shell bead was retrieved from this eroding surface along with five worked flints. The deposits were mostly protected within the drip-line of the shelter and were still mainly intact and in situ as shown by a compact surface layer (7) of marine shells, mainly winkle, which sealed a thin charcoal spread (9). The few surface



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Fig. 4.  A (top) Plan and cross profile of the rock shelter showing location of excavation. B (bottom) Profile of rock shelter and excavated trench. © Gwynedd Archaeological Trust. finds of worked flint and the cowrie shell bead may have derived from one of these exposed layers. One small sherd of pottery was found in shell layer 7. The horizon contained a further nine flints and some charcoal, mainly of hazel with some oak and willow/poplar, and shell layer 7 contained a charred cereal grain of indeterminate type. The charcoal in layer 9 was very finely comminuted and none was identifiable to species (see McKenna below). Horizon 2 The layers of horizon 2 were of humic loam suggesting a period of topsoil development, perhaps indicating a period without occupation and with little natural erosion of the adjoining rock face. At the west end of the trench and about 0.10m below the shell layer was a shallow hollow containing humic soil (8) on the

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base of which was a lens of charcoal. Below these was another thin humic layer (10), again with a lens of charcoal and a large flat beach cobble (SF 128) lying horizontally (Fig. 5) and a retouched flint tool fragment (SF 6). The beach cobble was of an imported fine-grained rhyolitic rock. Its position suggests it was used as an anvil or working slab although it had no obvious use-wear marks. Two small sherds of pottery, possibly Beaker were found in this horizon, in layers 8 and 10. The only other dating evidence from this horizon is provided by a retouched tool fragment, which is identified as a flint awl or knife of Neolithic or Bronze Age date (SF 6). The horizon contained many winkle and limpet shells as well as a few of mussel and whelk. There was some animal bone dominated by birds and small mammals with a few of domestic goat and pig. At the east end of the trench, on the outer edge of the rock shelter at an equivalent level to layer 10 was a layer of stony silt (6) that tipped down towards the scree slope at the east. This layer was penetrated by an animal burrow filled with dark humic material and the burrow continued through the layer below (13). Horizon 3 This comprised layers of fine grey silt that became increasingly loose and stony towards the west, the back of the shelter. The contexts of horizons 1 and 2 slightly overlapped a large horizontal slab of limestone (23), ascribed to horizon 3. This may have fallen from the shelter roof or have been deliberately laid as a



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Fig. 5.  A (top) Trench section, south side. B (bottom) Trench section, north side. © Gwynedd Archaeological Trust. hearth stone. Its surface was reddened, possibly burnt, and perhaps belonged with the overlying charcoal layer 9 of horizon 2. The slab was embedded up to 0.15m deep in this layer (contexts 16, 17 and 18), which consisted of very loose fine mid-grey silt. Horizon 4 This comprised two main layers and so was divided into 4a and 4b. The friable nature of these layers suggests a period of disturbance and perhaps deposition of eroding rock material preventing development of a stable soil. At the rear of the shelter larger pieces of possibly frost shattered rock accumulated. This shattered rock was loose and angular with many voids allowing finer material to migrate downwards and small mammals to invade. Mixing of artefacts and ecofacts is therefore to be expected. Horizon 4a This horizon (contexts 20, 22 and 24) was of fine mid-grey silt but with a high proportion of broken limestone fragments at the west, probably deriving from natural shatter from the cliff face. At the east

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end of the trench the equivalent layer was lighter-coloured silt. Although there was no evidence of humus or charcoal in these layers to suggest occupation activity they contained the largest number of pieces of worked flint, 18 pieces of Later Mesolithic type. Horizon 4a had been disturbed by a larger animal burrow, probably rabbit, and the burrow was identifiable, so its fill could be kept separate to avoid contamination (Fig. 5). Horizon 4b This horizon (contexts 28 and 30) was deeper and darker, a slightly humified layer of silt suggesting occupation activity, although it included only a small number of worked lithics. The lowest part of this continued into a slight but distinct hollow (29) (not visible in the side sections), containing a charcoal-rich soil (30) from which a radiocarbon date was obtained. Wood charcoal was present, with similar species to those in horizons 1 and 2 but with more charred hazel nutshell fragments. Small mammals were most numerous amongst the bone, indicating probable mixing. Bird and a few goat and pig bones were also found. Horizon 5 This mainly consisted of angular limestone fragments lying irregularly and interpreted as natural scree. It had many voids into which some of the overlying fine silts had fallen and although there were some artefacts and ecofacts in this horizon it seems likely that these were all intrusive from higher layers. There are relatively few lithic artefacts, no retouched tools, but several small blades of Mesolithic character. There were shells, mainly winkles and limpets and some bones of small mammals, birds and goats. At the rear of the shelter was a small concentration of charcoal (34) that could have been in situ, from which a radiocarbon date was obtained. The lowest layer (26), largely unexcavated, appeared to be natural scree although there were still a few flint fragments and charred nutshell fragments. This stony layer indicated intense weathering of the cliff face during harsher Late Glacial conditions. Excavation ceased at a maximum depth of c. 0.70m. It is possible, but seems unlikely, that there could be other, earlier phases of human occupation, below the level at which the excavation halted.

PREHISTORIC POTTERY By Frances Lynch The pottery assemblage comprises three small sherds and one crumb. All are hard red-surfaced pottery containing a good deal of well-crushed stone grit, including mica and quartz. They could all originate from the same pot (though they come from different contexts); they are certainly the product of the same potting tradition. The colour and well-crushed grits might suggest Beaker. SF 129. Small red/black crumb, closer to SF 130 than to SF 119, with an indentation which might be a whipped cord maggot. Horizon 1, context 7. SF 119. Small fragment (20×18×6mm) with a smooth red surface and less obvious grits, more Beakerlike but featureless. Horizon 2, context 8. SF 130. Body sherd (30×20×7mm), red on the outside, black inside with a lot of stone grit including several pieces of iron pyrites/mica. The grit breaks the surface on the outside. It has a hint of a slight raised cordon with a fingernail indentation below it. The red surface might have been covered with a beige slip. Horizon 2, context 10.



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IMPORTED STONES By David Jenkins Four stone objects were recorded that must have been introduced to the site from further afield. SF 128. Large flat beach cobble of fine hard igneous rock (200mm long×40mm thick) which seems likely to have been used as a working slab though there are no signs of attrition. Grey laminar slab of fine grained rhyolitic igneous rock, with edge encrusted with calcium carbonate deposit. Horizon 2, context 10. SF 164. Facetted angular quartz vein fragment which may have been part of a larger crystal that was struck to try to remove flakes, although no other pieces of crystal quartz were found. Horizon 3, context 14. SF 165. Pebble fragment, rounded with irregular fracture, possibly due to burning, which may have been part of a hammer stone, or a core reject. Very fine grey silicic igneous rock with thin white patina. Horizon 4a, context 20. SF 166. Small rounded quartz pebble (10mm diameter), stained brownish yellow from a sediment/ soil matrix. It is likely to have been introduced accidentally with collected shells. Horizon 4a, context 20.

COWRIE SHELL BEAD By Elizabeth A. Walker and Ben Rowson A perforated shell bead SF 11 (Fig. 6), was discovered on the surface of the rock shelter deposits presumably having been disturbed and eroded from its original context either by the goats that make use of the rock shelter, or by one of the many burrowing mammals known to have disturbed the site. The shell, identified as Trivia cf. arctica, the northern or arctic cowrie (see report by Ben Rowson) is 11.5mm across with and has two perforations 1.5mm across similar to those on cowrie shell beads found in other British archaeological assemblages. This is a species known to have been present in Britain for some

Fig. 6.  Perforated cowrie shell bead, Trivia cf. arctica. © Amgueddfa Cymru – National Museum Wales.

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considerable time and which, like Trivia monacha, could have re-colonised the British shoreline by the start of the Later Mesolithic. Both cowrie species are still found around rocky British coasts today. The most accessible and reliable distinguishing shell feature is the dark spots on Trivia monacha, which can be expected to have faded with use or in archaeological deposits. Just one other cowrie shell bead has been recorded from Wales, at Nanna’s Cave, Caldey Island, Pembrokeshire, which is also identified as Trivia cf. arctica (David and Walker 2004, 328). This bead, like that from Snail Cave, does not have a secure context. More securely dated parallels for this bead dating to the Later Mesolithic have been identified in the Wye Valley, Herefordshire, at Madawg Rockshelter (Barton 1993) and King Arthur’s Cave (Barton et al. 1997). Perforated cowrie shells have also been discovered in Mesolithic contexts at Three Holes Cave, Devon (Barton and Roberts 2004, 352). In Scotland perforated cowrie shell beads have been found associated with Later Mesolithic sites at Oronsay (Mellars 1987), Carding Mill Bay (Connock et al. 1992), Ulva Cave (Bonsall et al. 1994), and Sand (Hardy and WickhamJones 2002; Hardy 2007). This new discovery therefore adds to the known distribution of Later Mesolithic cowrie shell beads known from across the United Kingdom.

LITHIC ARTEFACTS By Elizabeth A. Walker A total of 146 worked pieces of flint, chert and stone were recovered during the preliminary visits and excavations. All the pieces that were identified as knapped were examined macroscopically in the National Museum Wales. Where it was possible to attribute artefacts to a specific archaeological period, this was done. This method resulted in 24 artefacts identified as Mesolithic or Later Mesolithic; four as possibly Mesolithic and just one as being of probable Neolithic or Early Bronze Age date. All the other pieces are considered to be prehistoric as they do not display characteristics that enable them to be attributed typologically to a specific period. Overall interpretation of the lithic assemblage is included in the concluding general discussion. Raw materials The dominant raw material present in the assemblage is flint. The majority of this is unpatinated and where this has not been burnt it is possible to see that there are a variety of different coloured flints represented. These include greys, black and honey coloured flints suggesting that their origin is not a single source. Many of the pieces have smooth pebble surfaces to their cortex. This and the amount of pieces that have cortex present suggest that the flint was obtained from a river or stream bed where it was available as small pebbles. Several of the pieces of flint in the assemblage have highly irregular forms and there are also a number that display thermal fractures that might suggest stream-chatter or freeze-thaw action. A range of cherts is also present in the assemblage; some of this is the fine-grained black Gronant chert available locally from near Prestatyn. Other sources might be available closer to hand, as chert occurs naturally in limestone, so other varieties might originate from the Great Orme itself. Two pieces of limestone appear to show evidence of conchoidal fracturing. One of these is a flake (SF 135) whilst the other is less certain (SF 134). Burnt lithics A number of pieces of worked flint were burnt (quantified in Table 2 according to site phasing). It is clear that there is a predominance of burnt pieces from horizon 4, the horizon which also contains the majority of the Later Mesolithic artefacts.



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Analysis of the assemblage by horizon The artefacts were allocated to archaeological horizons or phases based on field observation. The analysis that follows considers typological characteristics and other attributes, as well as context and phase. Table 2 shows the distribution of identifications by horizon. Horizon 1. Five worked flint and stone artefacts were discovered on the surface with the cowrie shell bead during visits to the site prior to the formal excavation. A further 9 worked pieces of flint and stone were recovered from surface layers during the excavation. None of these pieces are diagnostic to period. Horizon 2. This contained a burnt flint blade fragment with straight-convergent retouch leading to a point (SF 6). This tool has marginal and scalar retouch and there is a small thermal facture at the tip. The retouch does not extend across the dorsal surface of the tool and there is no retouch on the ventral surface. The tool is possibly an awl or the tip of a knife. It is unlikely to be an arrowhead fragment as the retouch is too steep and is intentionally restricted to a narrow edge of the tool on the dorsal surface only. Such a tool can be attributed to the Neolithic or Early Bronze Age period. The presence of possible Beaker pottery within this same context suggests a relationship between the two. Other finds from this horizon are undiagnostic to date and comprise mainly flake and blade knapping debitage.

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Horizon 3. This contained one prehistoric flint flake, two flint flake fragments, one possible burnt stone flake (possibly the cortex from a flint nodule), one small chert spall and two possible Mesolithic utilized blades (SF 27 and SF 28). SF 27 is the mesial fragment of a blade with clear evidence for utilization along both the surviving lengths of the blade. SF 28 is a complete blade of 33.9mm in length. It has irregular chipping running along both its lengths which is very marginal. When examined under a microscope the chipping can be seen to be irregular and on both the dorsal and ventral surfaces. The blade has a dorsal crest and tapers towards its distal termination. Both pieces might be of Mesolithic date. Horizon 4. This contained the majority of the worked lithic artefacts, 90 in total. Amongst these are 18 pieces that can be attributed to a Later Mesolithic date; two of possible Mesolithic date and 68 of prehistoric age. The Later Mesolithic group includes six complete microliths and five microlith fragments. The other seven pieces are small blades or bladelets suitable for microlith manufacture. The possible Mesolithic tools include an awl or piercer (SF 36) of a type that is not easy to date with any certainty. It is made on a blade of speckled black mudstone or chert that has had its distal end trimmed to an acute angle with fine marginal retouch forming the point. The lengths of the blade are unmodified. Another tool (SF 109) is a utilized blade where the evidence for its utilization is limited to a 10mm length. The rest of the finds from this horizon are predominately fragments of blades, flakes, spalls and general knapping debitage that are difficult to attribute with any certainty to any specific period. Any, or all, of this might be contemporary with the Later Mesolithic date of the microliths, and it is due to the possibility of some downward movement of material between the cavities in the stones contained within this horizon that caution is expressed in their attribution here. Horizon 5. These are the lowest layers of the site and this horizon contains sixteen worked pieces of flint of which a small bladelet core (SF 41) and two bladelets are considered to be of Later Mesolithic date. Of the other pieces from this horizon six blade fragments and one blade might also be of Later Mesolithic date. The rest of the pieces are flakes and other pieces of general prehistoric knapping debitage. Lithic artefacts (Fig. 7) Microliths The assemblage contains six complete and five fragmentary microliths. The microliths are all of Later Mesolithic forms and are consistent with the definition of the narrow-blade microlith provided by Radley and Mellars (1964) as being of