Plumstone Rock

Somehow or other, Plumstone rock has escaped our attention.  It is a prominent rhyolite tor located on the ridge of Ordovician volcanic  rocks that runs between Roch Castle in the west (near Newgale)  and Trefgarn Gorge in the east.  The most prominent crags on the ridge are Poll Carn (Lion Rock) and nearby Maiden Castke (called by the locals the "family of lions" for obvious reasons).   

The rocks are for the most part flinty bluish rholotes, with considerable internal variation, including welded tuffs and agglomerates.  In certain light conditions the rocks appear to be pinkish or orange in colour.  The age of these rocks was disputed for many years, having been originally labelled as Precambrian -- but they now seem to be accepted as Ordovician.

The rock is hugely impressive and intimidating -- but  it is easily accessible from the Haverfordwest - Hayscastle road, and there is an easy short walk to the tor from the car parking area on the common.

It does not have the fragility of  Maiden Castle, and while the bulk of the tor is solid bedrock, on its flanks there are numerous massive detached blocks.  It is -- naturally enough -- a facvourite place for "bouldering".  I have not seen any striated surfaces on the tor, but there are some forms that are suggestive of ice moulding.  The big question is this -- what do the four tors on this ridge tell us about the history of glaciation across Pembrokeshire?

Newgrange: too much mythology and not enough facts

In this rather interesting article there is a timely assessment of some of the mythology surrounding Newgrange -- probably the most iconic prehistoric site in Ireland. The authors point out that many of the assumptions about Newgrange being a "special" place built by a powerful ruling clan as a tribute or homage to a "king" or powerful ruler are based on very little evidence -- or no evidence at all. They suggest that Newgrange was built over a very long period in many different phases, and that those buried there were not necessarily related, or people of high status within a ruling elite. They prefer a simpler story, devoid of heavy symbolism and romanticism -- indeed, somehat utilitarian and somewhat boring.

There are lessons here for all of us -- especially those who have developed the fanciful West Wales narrative of sacred and special places, magical stones, heroic quarrying activities and even more heroic long-distance stone haulage expeditions........

The post-processual obsession with fanciful narratives has a lot to answer for.

It might just be a good idea for the archaeologists working in West Wales to go back to basics and work out just what evidence there is on the ground, as suggested by quite a few of us from other disciplines over the years.




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Smyth J, Carlin N, Hofmann D, et al. The ‘king’ of Newgrange? A critical analysis of a Neolithic petrous fragment from the passage tomb chamber. Antiquity. 2025;99(405):672-688. doi:10.15184/aqy.2025.63

ABSTRACT

Recent genomic analysis of a skull fragment from Newgrange, Ireland, revealed a rare case of incest. Together with a wider network of distantly related passage tomb interments, this has bolstered claims of a social elite in later Neolithic Ireland. Here, the authors evaluate this social evolutionary interpretation, drawing on insecurities in context and the relative rarity of engendered status or resource restrictions in the archaeological record of prehistoric Ireland to argue that the status of individuals during this period is better understood through unstable identity negotiations. Inclusion in a passage tomb, while ‘special’, need not equate to a perpetual elite.

Carn Fran summit

 

Many years ago (about 63, to be more precise) Francis Synge pointed out to me that the rhyolite hills between Fishguard and Dinas were rather interesting.  He pointed out how smooth and rounded they were, in contrast to the craggy uplant tors found at higher altitudes on Mynydd Dinas, Carningli and Mynydd Preseli.  The main summits are Carn Fran and Carn Gelli, and there are half a dozen minor summits as well.  They are all "clean" and relatively smooth, and a number of geomorphologists in the past have suggested that they were glaciated quite recently while the other higher summits were above the upper glaciation limit.  

Nowadays it is accepted that that interpretation is rather simplistic, and that changes of landscape characteristics may be related to changes in glacier bed conditions.  Thin ice on rounded upland terrain may have been frozen to its bed -- ant therefore incapable of intensive erosion -- while thicker ice in the lowlands may have been above the pressure melting point, flowing faster and with greater erosive capacity........

In the past I have never managed to get up onto the summits of these hills because of thick vegetation -- gorse, brambles, heather and bracken.  But in recent years a "permissive path" has been opened, and this gives easy access to Carn Fran.  We have been doing some work up there -- more of which in due course......

 

The Foel Drygarn quarries

 

I have done a number of posts on the Bronze Age and Iron Age quarries near the summit of Foel Drygarn.  I was up there a couple of weeks ago, and this is one of them.

  I am quite convinced that the quarrymen were quite disinterested in large blocks of stone, and targetted rubble and small stones that could be used in the 3 spectacular burial mounds on the summit and in the defensive embankments around the settlement site.  In most cases all they had to do was to take loose stones from banks of scree -- but in some cases they have clearly taken loose stones from the degraded flanks of the rhyolite and micro gabbro tors.

Nothing much was needed in the way of technology, although I would guess that wooden levers might have been used in order to extract the stones from the ground.

A Foeldrygarn puzzle

This is a photo of one of the microgabbro outcrops near the summit of Foeldrygarn.  The outcrop is a small one, surrounded by grassy banks.  It's a degraded small tor, but here the focus of interest is the semi-circular arrangement of stones set in the turf.  This is quite unlike anything I have seen elsewhere in Preseli.  There are plenty of semi-circular stone banks set against small cliffs in the uplands of Preseli, but these are characteristically composed of curving lines of boulders or low ridges up to 2 m wide.  Some appear to have been low walls that maybe supported roof timbers -- with the upper ends of the timbers supported against the rock face.

Here on Foeldrygarn we see a "band" of large boulders or slabs, many of which seem to have been placed end to end...........

The site lies within the summit hillfort and not far from the triple Bronze Age burial mounds -- all made with locally quarried stones which were carried short distances uphill.  The stones were all small enough to carried by one man -- or sometimes two men working together.  Large boulders and slabs were rejected on the grounds that they were unmanageable -- and maybe this holds the clue to what was going on.  Maybe the "band" of large stones was made entirely of rejected stones, pushed aside while the smaller stones and finer debris fragments were carried away for the construction of bural mounds and later for the fortified mounds that are prominent features of the site?

Has anybody seen anything like this elsewhere?  Any other theories about what was going on here?

Carnalw

 Another of Hugh Thomas's wonderful Preseli images -- this one shows Carnalw, near the eastern end of Mynydd Preseli.

The Blatten Glacier Disaster

Before.........

.... and after

There is a fascinating piece of reportage (with spectacular animation) on the BBC web site, relating to the recent disaster in the Swiss Alps.

https://www.bbc.co.uk/news/resources/idt-c7f929de-96a9-45e5-b1bb-31de82fce72d

Thank goodness there was no loss of life, since the idyllic village had already been evacuated, prior to the catastrophic event.  I thought, before I looked into this, that the "glacier collapse" took place in the upper part of a regenerated glacier, like that of Supphellebreen at Fjaerland in Norway -- but no, this was a very small and very dynamic independent glacier (Birch Glacier) in a high mountain environment.  High rates of snow accumulation, steep slopes, and rapid ice flow under the influence of gravity, on slopes dominated by frost shattering and rockfalls. Permafrost melting and rainfall in the Alps (as distinct from snowfall) were contributary factors in causing additional debris mobility.   

The old photos show a substantial fan of debris close to the village, with no clear terminal or other moraines.

There is no doubt at all that collapses like this will now occur with increasing regularity in all of the high mountain environments where there are thousands of vulnerable glaciers of this type.......

(For very good enlargements of the images, just click on them.)