Cwm Mawr "axe factory" and the sources of picrite

 

The "axe factory" site -- a small rocky knoll in a verdant landscape

On hunting down some sources on picrite (the famous boulder featured on this blog), I have been intrigued by the literature relating to the Cwm Mawr "axe factory" near Churchstoke, Montgomeryshire.  In articles all over the place it is spoken of with great certainty, in spite of the official record which records that there is nothing much there to write home about:

The Coflein record:

Hill of distinctive picrite rock, identified in the Proceedings of the Prehistoric Society in 1951 as the probable source of stone for the Group XII Bronze Age battle axes and axe hammers, by Shotton, Chitty and Seaby. Their work identified several former quarry sites and outcrops of the rock on the hill. Excavations by the Clwyd Powys Archaeological Trust, in conjunction with the National Museum Wales, were funded by Cadw in 2007 & 2008. Initial results were inconclusive, finding only evidence for historic use of the quarry.

T. Driver, RCAHMW, 9th October 2008.

https://coflein.gov.uk/en/site/408335/

There are entries on the Magalithic Portal and the Modern Antiquarian which demonstrate the wide acceptance of the idea that this was the place at which Bronze Age quarrymen dug out lumps of picrite which were then fashioned into hand axes or battle-axes that were traded across a vast swathe of the countryside.  This is typical: "This quarry is proving to be the source of many stone implements, including axe hammers of Bronze Age date........."

and this:

Archaeologists working for the Clwyd-Powys Archaeological Trust (CPAT) say that Group XII Bronze Age battleaxes and axe hammers fashioned from picrite, a distinctive form of basalt, were probably made at a quarry site at Cwm Mawr just to the north-west of the village of Hyssington in eastern Montgomeryshire. The axes are found as far apart as Cornwall and the north of England, but are most common in Wales, the Marches and the West Midlands.

Hmmm.  I think we are in the presence of some unsafe assumptions here, not to mention confirmation bias.....

The problem is that there is no Bronze Age quarry at Cwm Mawr, and there is not much critical analysis either. There are many outcrops of picrite in the British Isles, and I have not seen any published evidence that indicates that all of the axes made of this material have all come from a single source. In spite of this Group XII axes are often referred to as "Group XII (Cwm Mawr)" axes on the basis of rather cursory geological examination.

See this excellent RIGS note relating to picrite erratics in Anglesey:

https://www.geomon.co.uk/llanerchymedd-rigs-site/

A friend has also drawn my attention to this article, published last year:

https://www.cambridge.org/core/journals/antiquaries-journal/article/from-the-heat-of-the-fire-a-biography-of-an-early-bronze-age-battleaxe-from-church-lawton-cheshire/40718969F43658F3670DE0E6C10861ED

The artefact described was found at Church Lawton, about 80 km NE of Cwm Mawr.  In the article the axe head is NOT definitively provenanced to Cwm Mawr, in spite of the reproduction of two very colourful thin sections.  It is simply assumed to have come from "the Cwm Mawr Farm quarry".  Then the authors say this:  

Although Group XII extraction sites dating to the Early Bronze Age have not been positively identified, it is thought that blocks of picrite (cobbles) in stream beds near to the hill were most probably used for the production of axe-hammers and battle-axes. Such cobbles would have been closest in size and shape to the intended products, thereby helping to reduce effort during manufacture. They would also have had the advantage of being ‘flaw tested’ through the action of rocks hitting one another caused by the movement of water.

The movement of water?  What about the movement of ice? The authors have apparently not noticed that there are picrite erratics scattered across the landscape (as in Anglesey), or that there was such a thing as the Ice Age.  But wait -- they do acknowledge the presence of nine "glacial boulders" surrounding the investigated barrow mound.  So they recognize non-picrite glacial erratic boulders, but not picrite ones.  Clearly it is very unlikely that ice can have carried Cwm Mawr picrite boulders far to the north-east, because all the evidence shows a broad north to south ice flow direction.  But the map of picrite artefact distribution in southern Britain has one fundamental flaw -- and that is the assumption that all the picrite artefact finds are made of picrite from Cwm Mawr. 

I am prepared to accept that picrite axes (and axes of many other rock types) were fashioned in many different places, and were widely traded, but it is quite extraordinary that archaeologists (and geologists) can spend so much time talking about imaginary quarries and "raw material selection" without once referring to glacial erratics.  Once again, too much storytelling, too much blind adherence to the establishment line, and not enough critical thinking.