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The location of Craig Rhosyfelin, on the west side of the Brynberian Valley. The rocky spur of foliated rhyolite is seen in the centre of the photograph, close to the hairpin bend in the road.
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ABSTRACT
Following the publication of a geological paper by Ixer and Bevins (2011) that provenanced certain rhyolite fragments in the Stonehenge "debitage" to a rocky crag at Craig Rhosyfelin in North Pembrokeshire, Parker Pearson and his archaeological colleagues announced that "the Pompeii of prehistoric stone quarries" had been found at the sit...
Context in source publication
Context 1
... Rhosyfelin (SN117362), near Brynberian in North Pembrokeshire, has recently become the focus of attention for both earth scientists and archaeologists interested in the Stonehenge bluestone enigma. The question “How did 43 bluestones find their way from West Wales to Salisbury Plain?” has exercised minds for more than a century, and there is still no consensus. Geomorphologists tend to the view that the bluestones at Stonehenge are a suite of glacial erratics, transported by the Irish Sea Glacier (John, 2008: 160). Archaeologists tend to the view that the stones were transported by Neolithic tribesmen in one of the great technical feats of the prehistoric era (Cunliffe and Renfrew, 1997, 362). But in 2011 geologists Rob Ixer and Richard Bevins announced that they had accurately provenanced fragments of a peculiar type of foliated rhyolite from the Stonehenge “debitage” to the Rhosyfelin neighbourhood. This encouraged an immediate quarry hunt, and in September 2011 a team of archaeologists led by Mike Parker Pearson announced that “the Pompeii of prehistoric stone quarries” had been found (Parker Pearson, 2012). The archaeological excavations at Rhosyfelin have recently been completed after five seasons of fieldwork, and the investigated pits have now been filled with spoil and re- seeded. However, since parts of the dig site have been left open from one season to the next, it has been possible to examine carefully the landforms and sediments at the site. The Quaternary sedimentary sequence has already been described and interpreted (John, Elis-Gruffydd and Downes, 2015). This short paper does not discuss the pros and cons of the bluestone transport debate, but describes the natural phenomena at the site and then assesses some of the suggestions made by Parker Pearson and his colleagues about Neolithic quarrying activities. Craig Rhosyfelin is located in the valley of the Afon Brynberian, on the northern flank of Mynydd Preseli (Fig. 1). It is a rhyolitic rocky spur about 80m long, aligned approximately NE-SW and with a number or precarious 1 Trefelin, Cilgwyn, Newport, Pembrokeshire SA42 0QN brianjohn4@mac.com 2 Ty’r Ardd, Llechryd, Ceredigion SA43 2NR dyfedelisgruffydd@btinternet.com 3 Mount Pleasant Cross, Cosheston, Pembroke Dock, Pembrokeshire SA72 4TZ jd1936@btinternet.com rock pinnacles on its crest. It supports a dense vegetation cover of gorse, brambles and scrub woodland, and following archaeological clearance work a steep NW-facing rock face has been exposed. All of the rhyolitic crags in this neighbourhood are erosional remnants of Fishguard Volcanic Group outcrops (see BGS Sheet 210 Fishguard). The lavas are of Mid Ordovician age, and they dip steeply northwards. On the Rhosyfelin rock face there are deep almost vertical fractures with numerous horizontal cross fractures. Many of the fractures coincide with foliation planes. The rhyolite is a splintery dark blue rock which weathers to a light grey colour. Some substantial quartz veins are also visible. A considerable amount of rock debris has accumulated at the foot of the steep rock face. The geological findings relating to the Rhosyfelin “foliated rhyolite with Jovian fabric” are described by Ixer ...
Citations
... As at Rhos-y-felin, there have been no control investigations carried out at the other tors which might demonstrate that this "quarrying site" was in some way unique or important. The evidence for "engineering features" at Rhos-y-felin has been systematically examined in two detailed papers (John et al 2015a(John et al , 2015b) and all of these features have been found to be commonplace, and in the author's opinion entirely natural (Figure 11). In fact those involved in the archaeological dig at Rhos-y-felin were accused by the present author and his two colleagues of the selective removal of sediments and the creation of "archaeological artifices" in their search for evidence of quarrying. ...
This paper examines the hypothesis that Carn Goedog, a prominent tor on the north flank of Mynydd Preseli in Pembrokeshire, Wales, was the site of a Neolithic quarry from which Stonehenge bluestones were extracted on a large scale. The dolerite sills in the area are geochemically heterogenous, with multiple outcrops. Claims of "precise provenancing" of Stonehenge spotted dolerite fragments to Carn Goedog are questionable. Geomorphological studies on the tor reveal that pillars suitable for use as monoliths are restricted to a few small areas, difficult to access. Frost-shattered blocks dominate. Many have sub-rounded edges, suggesting long-term weathering and redistribution by glacier ice. Moulded and smoothed surfaces indicate that the influence of overriding ice associated with the Irish Sea Ice Stream has been considerable. Examinations of the supposed "Neolithic quarry" site reveal that many of the "engineering features" may be natural. The materials referred to as stone artefacts are not obviously related to quarrying activities, but may instead point to a history of intermittent occupation. The soft shale "wedges" supposedly used for extracting pillars from the rock face may be natural and are ubiquitous. Radiocarbon dating does not appear to support the quarrying hypothesis. Thus the evidence for a Neolithic quarry at Carn Goedog is poor. If blocks and pillars of spotted dolerite were indeed extracted and transported away from the vicinity of the tor in prehistory, the agency is most likely to have been glacier ice.
... This new narrative has been disputed (for example, by Elis-Gruffydd, 2017 andJohn et al, 2015) on the grounds that "bluestones" of rhyolite or dolerite were not preferentially used -and were therefore not greatly revered -in West Wales Neolithic stone settings; that the presence of bluestone quarries has not been adequately demonstrated; that the Waun Mawn stone circle (deemed to be a place where bluestone monoliths were "parked up" for several centuries) never actually existed; that no evidence has ever been found to support long-distance bluestone transport across sea or overland; and that the bulk of Stonehenge bluestones are not elegant pillars but heavily weathered and abraded boulders that would not be out of place at any present-day glacier snout (Fig. 8). Nonetheless, the narrative has been repeated multiple times by Parker Pearson and his team (e.g. ...
A large unspotted dolerite erratic boulder was discovered in 2022 on the rocky foreshore in Limeslade Bay near the SE tip of the Gower Peninsula. It is about 2.2m long, weighs about 5 tonnes and rests in a gully where it is subjected to wave action at every rise and fall of the tide. Its surface is heavily abraded and it may have been substantially reduced in size since its original emplacement. It has a greenish colour and is described as a metamorphosed coarse dolerite or ophitic microgabbro. Thin section analysis and pXRF analysis suggest that it is not related to the spotted and unspotted dolerites of Mynydd Preseli, and that it is most likely to have come from one of the Ordovician igneous outcrops near the north Pembrokeshire coast between St Davids and Fishguard. It is not known whether the rock type is precisely matched in any of the bluestones (monoliths or rock fragments) in the Stonehenge landscape. It is unlikely that this erratic was transported by floating ice, since near the peak of a glacial episode sea-level must have been at least 80m lower than it is today. Further, of the scores of known glacial erratics on the shores of the Bristol Channel, many are found at altitudes in excess of 100m, indicating that during at least one glacial episode the ice of the Irish Sea Ice Stream was thick enough and dynamic enough to press inland across the coasts of Devon and Cornwall. It is therefore probable that glacier ice also reached Salisbury Plain, and that the bluestone boulders and smaller fragments at Stonehenge — from more than 30 different sources — were glacially transported.
... Other attempts to demonstrate human involvement in the creation of micro-features include reference to an !artificial mound" and a !sunken trackway". But these are not adequately described, and they are no more convincing than the "engineering features" described at Rhos-y-felin and Carn Goedog by Parker Pearson et al and then heavily criticised by John, Elis-Gruffydd & Downes (2015a, 2015b. The "mound" is no larger than many of the other mounds in the neighbourhood, and has no archaeological significance. ...
... None of the claims made in this extract with regard to Waun Mawn, Rhos-y-felin or Carn Goedog is adequately supported by evidence in the field. As indicated by John, Elis-Gruffydd & Downes (2015a, 2015b natural features at Rhos-y-felin and Carn Goedog have been misinterpreted as man-made quarrying features. The radiocarbon dating evidence essentially falsifies the quarrying hypothesis. ...
This paper examines the hypothesis that Waun Mawn in West Wales provided the bluestone monoliths that were used at Stonehenge. Some archaeologists believe that the site supports the last remains of a giant stone circle or ‘Proto Stonehenge’ which was dismantled and transported to Salisbury Plain around 5000 years ago. It was claimed, after three excavation seasons at Waun Mawn in 2017, 2018 and 2021, that there is firm evidence of some standing stones which were later removed or broken up, but it has still not been demonstrated that there ever was a small stone circle here, let alone a ‘giant’ one. Furthermore, there have been no control studies in the neighbourhood which might demonstrate that the speculative feature has any unique characteristics. There is nothing at Waun Mawn to link this site in any way to Stonehenge, and this is confirmed by recent cited research. No evidence has been brought forward in support of the claim that ‘this was one of the great religious and political centres of Neolithic Britain’. It is concluded that at Waun Mawn and elsewhere in West Wales there has been substantial ‘interpretative inflation’ driven by the desire to demonstrate a Stonehenge connection.
... Brilliant fieldwork, or assumptive research driven by circular reasoning? The evidential basis of the quarrying claims has been questioned in two peer-reviewed papers by Downes (2015a and2015b), for reasons also laid out by John in The Stonehenge Bluestones (2018). ...
This paper examines Waun Mawn in its regional context, on the northern flank of Mynydd Preseli in Pembrokeshire. The geology is typical for the area, with outcrops of Ordovician mudstones and meta-mudstones and igneous rocks belonging to the Fishguard Volcanic Group. The landscape has been intensively glaciated on more than one occasion, and glacial and periglacial deposits are widespread. There is an extensive litter of erratic boulders (mostly of dolerite) scattered across the hillside. Many of these boulders have been used in prehistoric stone settings around Waun Mawn, Tafarn y Bwlch and Banc Llywdlos. Included in these stone settings are single and double standing stones, ring cairns, hut circles, passage and gallery graves, and what appear to be collapsed cromlechs. Parker Pearson (2017, 2019, 2021a) has claimed that Waun Mawn carries traces of a dismantled “giant stone circle” which provided bluestone monoliths for Stonehenge. The evidence cited in three publications is examined. In relation to the shallow excavations in 2017, 2018 and 2021, it is concluded that there might have been some small standing stones which were later removed or broken up, but it has still not been demonstrated that there ever was a small stone circle here, let alone a “giant” one. Furthermore, there have been no control studies in the neighbourhood which might demonstrate that the speculative feature has any unique characteristics. There is nothing at Waun Mawn to link this site in any way to Stonehenge, and it is concluded that the archaeologists have simply “discovered” what they wanted to find, and have created an elaborate and unnecessary bluestone narrative around it. No evidence has been brought forward in support of the claim that “this was one of the great religious and political centres of Neolithic Britain”. In 2021 Parker Pearson and colleagues finally acknowledged that there never was a “giant stone circle” at Waun Mawn, but continued to refer to an “unfinished stone circle” and maintained that the feature was linked to Stonehenge. However, in 2022 two new geological papers were published, one showing that there was no Stonehenge link, and the other showing that bluestone 62 at Stonehenge came from eastern Preseli and that it had nothing to do with any stone socket at Waun Mawn.
... This new narrative or myth has been hotly disputed (for example, by John et al, 2015) on the grounds that "bluestones" of rhyolite or dolerite were not preferentially used -and were therefore not greatly revered --in West Wales Neolithic stone settings; that the presence of bluestone quarries has never been convincingly demonstrated; that the Waun Mawn stone circle (deemed to be a place where bluestone monoliths were "parked up" for several centuries) never actually existed; that no evidence has ever been found to support long-distance bluestone transport across sea or overland; and that the bulk of Stonehenge bluestones are not elegant pillars but heavily weathered and abraded boulders that would not be out of place at any present-day glacier snout. Nonetheless, the narrative has been repeated multiple times by Parker Pearson and his team (eg Parker Pearson et al, 2021), and has been made more and more complex, with hard field evidence increasingly difficult to come by. ...
This interim report concerns the chance discovery of a very large igneous erratic on the foreshore of Limeslade Bay, Mumbles, Gower. In this position it must have been glacially transported from the west by the Irish Sea Glacier as it moved eastwards up the Bristol Channel. If the glacier was able to resist the pressure of Welsh ice coming from the north, it must have been a very powerful ice stream capable of reaching Somerset and Wiltshire. The significance of this research is discussed with respect to Quaternary studies and archaeology. There are major implications for the debate surrounding the mode of transport of the Stonehenge bluestones. Detailed provenancing work for the erratic is under way.
... Over and again, they have described commonplace features and invested them with signiDicance. The evidence for !engineering features" at Rhos-y-felin has been examined in two detailed papers (John et al, 2015a(John et al, , 2015b and all of them have been found to be entirely natural (Fig. 11). Those involved in the archaeological dig at Rhos-y-felin were accused of the selective removal of sediments and the creation of !archaeological artiDices" in their search for evidence of quarrying. ...
This paper reports on new observations at the spotted dolerite tor of Carn Goedog on Mynydd Preseli, claimed by Parker Pearson and others to be the site of a Neolithic "bluestone monolith quarry" with links to Stonehenge. No evidence was found to support the contention of prehistoric quarrying, and indeed the claimed "engineering features" are all shown to be entirely natural and unexceptional. This work should be read alongside the two peer-reviewed papers by John, Elis-Gruffydd and Downes (2015 a and b) which show that the claims of Neolithic monolith quarrying at Craig Rhosyfelin (also excavated by Parker Pearson and his team) are similarly unfounded. It has to be concluded, on careful scrutiny of the evidence, that there are no Neolithic bluestone quarries in West Wales and that any blocks of local rock moved eastwards from Preseli to Salisbury Plain were most likely entrained and transported by glacier ice.
... With respect to the Iron Age, the authors report on a number of dated horizons. There are no descriptions of the characteristics of these layers or their relationships, and the text simply confirms in the mind of the reader that Rhosyfelin was a place of intermittent prehistoric occupation over a very long period of time, most probably related to seasonal migrations and hunting and gathering activity (John, Elis-Gruffydd and Downes (2015b). ...
... This is a strange statement, given that there are hundreds of tonnes of rockfall debris and shattered rock against the rock face. The authors suggest that since it was easy to extract stones with the aid of wedges, that was what happened.!They say:! "In the case of the recess from which the 'rhyolite with fabric' monolith was extracted, a 0.07m-wide indentation on its north edge appears to be a hollowed-out wedgehole."! From a detailed examination of this feature, it is suggested that it is not man-made (John, Elis-Gruffydd and Downes (2015b). ...
... In response to this speculation, it has been stressed by John, Elis-Gruffydd and Downes (2015b) that in spite of five seasons of meticulous searching at Rhosyfelin, no mauls, hammerstones or wedges have been found. As pointed out above, there are no picks, tools or other Neolithic or Bronze Age artifacts. ...
The origin of Stonehenge's bluestones, the smaller stones integral to the monument, has been a focal point of archaeological and geological inquiry for decades. The prevailing view, supported by recent excavations, suggests these stones were quarried from specific sites in Wales, such as Craig Rhosyfelin, Waun Mawn, and Carn Goedog, and transported to Stonehenge by Neolithic communities around 3000 BC. However, Brian John, a geologist, has challenged this narrative through a series of papers published in 2015, 2024, and 2025, advocating for a glacial transport hypothesis. This review synthesizes detailed analyses of these three papers, highlighting their strengths and weaknesses, and situates them within the broader context of current research on Stonehenge's bluestones.
There has been considerable dispute over the mode of transport of the Stonehenge bluestones from their multiple sources in West Wales. For a century most archaeologists have accepted that the stones were transported by humans, but a number of earth scientists have taken the view that they were entrained and transported to Salisbury Plain by glacier ice. There is remarkably little evidence in support of either theory, and for this reason any new description of a possible glacial clast found at or near the stone monument is of potentially great importance. A small bullet-shaped boulder of welded tuff was found in a Stonehenge excavation in 1924, and apart from a brief examination by geologists from the Institute of Geological Sciences (IGS) around 1970, it has been stored out of sight and out of mind. Its geological source is uncertain. Following a detailed examination of its shape and surface characteristics it is now proposed that it has been subjected to glacial transport and that it has had a long and complex history. It is also proposed that the abundant weathered and abraded bluestone boulders and slabs at Stonehenge were also glacially transported, along with many of the cobbles and stone fragments found in the sediments of the local landscape. The elaborate archaeological narrative of bluestone quarrying and human transport to Stonehenge must now be re-examined.
