A Long History of Rhosyfelin (revised)

8/11/2019 A Long History of Rhosyfelin (revised)

http://slidepdf.com/reader/full/a-long-history-of-rhosyfelin-revised 1/22

A Long History of Rhosyfelin:

A Geomorphological Perspective

Brian John

If you type in "Rhosyfelin" into Google, you will find a good many entries, including many from my

blog called “Stonehenge and the Ice Age” (1). For better or worse, the site at Craig Rhosyfelin, not

far from Brynberian, has become a key archaeological site -- which is rather interesting, given that

there is not much archaeology there.

Its new-found fame, of course, lies in the fact that some of the "debitage" at Stonehenge has been

traced back to this particular rather insignificant rocky spur in the valley of the Brynberian River, a

tributary of the Afon Nyfer. The link has been featured in a number of papers by Rob Ixer and

Richard Bevins (2) -- all discussed at length in my blog. More to the point, for the past four seasons

there have been extensive archaeological digs on the site, with Mike Parker Pearson, Josh Pollard

and Colin Richards all involved, along with a host of other amateur and professional archaeologistswho are all apparently sold on the idea that this is the first proper "bluestone quarry" ever to be

systematically investigated. That is the hypothesis, as enunciated in some detail by Prof MPP in his

1

Map and satellite image from the “Where’s the Path?” website. The rocky spur is located just to the east of the verytight bend in the road. The dig site is between the two prominent mayflower trees and the rocky ridge.



2012 Stonehenge book (3). To me, it looks like a ruling hypothesis, because it has simply been

accepted as correct, and has not been tested. There have been no published survey reports or peer-

reviewed papers thus far -- and this is interesting, given that this project started in 2011, more than

three years ago.

Why this tardiness? This may be down to the strict veto exercised by the National Geographic

Society, which seems to be financing the dig, and which (according to MPP in his Brynberian talklast September) does not allow anything to be published without its consent. Presumably it wants a

"world exclusive" in the pages of the National Geographic Magazine. I’m inclined not to believe

that -- after all, MPP has revealed many of the details of the dig in his book, and that presumably

was published with a nod from the publishers of the magazine. Also, if anything spectacular really

had been found, nobody would have been able to restrain MPP or any of the others involved from

going public. There would have been banner headlines and excited press conferences. No -- it is

much more likely that nothing very interesting has been unearthed thus far; and that is why the

diggers have returned for another session in September 2014. The team members are determined

to find the Holy Grail -- incontrovertible evidence of quarrying and the removal of stones from thissite all the way to Stonehenge. If at first you don't succeed.........

2

The 2011 excavation at Rhosyfelin, showing the “abandoned orthostat” of foliated rhyolite which has come from theadjacent rocky spur. Note the apparent stratification in the exposed sediments. If any organic material from any ofthese sediment beds should yield a radiocarbon date greater than 5,000 years BP, that would invalidate the quarry

hypothesis.



We don't know what dating techniques have been used on samples from the site. There are organic

materials in some of the exposed layers in the stratigraphy, and we know that radiocarbon dating

has been used. But other dating techniques -- including cosmogenic or OSL dating -- may also have

been appropriate with a view to working out the sequence of sedimentation. Why have no

radiocarbon dates been published? Well, some bloggers suspect a deep conspiracy on this front --

and I have to agree with them that this lack of publication probably means that the sequence of

events which is emerging is not particularly favourable to the "bluestone quarry" hypothesis. Afterall, if any date greater than 5,000 yrs BP is given to material stratigraphically above the base of the

big "recumbent orthostat" which has appeared in all the photos, that would knock the whole

hypothesis for six. I might even speculate that dates considerably in excess of 5,000 yrs BP --

placing them in the Mesolithic or Palaeolithic -- have been found already. No doubt all will be

revealed in due course.

I have never been invited to have a look at the dig, and my one appointment with members of the

team was a grave disappointment since they failed to turn up at the agreed time at Rhosyfelin, so

my impressions are based on quick visits in the company of others and on a lack of proper

fieldwork. However, I have a good photographic record of the site, and I have listened intently to

the presentations given to the general public by MPP and his colleagues. So here is my

interpretation of the landscape history of the site. Let's call it a Long History of Rhosyfelin -- since

the timescale is indeed a long one, measured in millions of years. In my view this is a Pleistocene

site, not a Neolithic one.

THE SEQUENCE OF KEY EVENTS

This, I think, is the history of what has happened to the landscape and landforms at Rhosyfelin. It

is intended for use as a working hypothesis, subject to correction and improvement -- and maybe

even to falsification, according to the precepts of Karl Popper! If it needs to be dumped in thefuture, so be it...... and in the meantime, I will welcome comments and corrections.

1. Phase One. Early Days.

There was a long period of landscape evolution prior to the Ice Age, during which the main features

of upland and lowland were created. The upland ridge of Mynydd Preseli is all that is left of a

much more extensive mountainous landscape. We can assume that there were once spectacular

alpine peaks here, created during the Caledonian mountain-building episode around 450 million

years ago, and then maybe influenced also by the Hercynian upheavals of 350 million years ago.

(These are very rough dates -- in reality those episodes were prolonged and complex.) There was

much volcanic activity in connection with these upheavals; the Fishguard Volcanic Series of igneous

rocks was emplaced around 450 million years ago, within and on top of old sea-floor sediments

which now outcrop at the ground surface across much of North Pembrokeshire (4). You can see

traces of the mountain-building episodes in the tight folds, faults and shattered rock zones in the

cliffs at Ceibwr, Newport and many other locations between Pen Caer and Cardigan. Many of

these rocks in the uplands have been eroded away -- maybe because of the frequency of volcanic

ashes and flaky rhyolites mixed in with mudstones, shales and thin-bedded sandstones. In a popular

terminolgy, these would be called "soft" rocks. In contrast, the big intrusions of dolerite in the

Preseli Hills have been much more resistant to erosion, explaining the rolling upland landscape with

a scatter of dolerite (and some rhyolite) tors.

Why are the tors there? Conventionally, the explanation is that the tors survive because they are

made of resistant rocks which are not broken by tight jointing and fractures, whereas the heavily

3



fractured and "softer" rocks around them have been attacked by chemical and physical weathering

processes on a more substantial scale. These tors (like Carn Meini, Carn Alw, Carn Bica and Carn

Arthur) have probably been present as features in the landscape for at least 10 million years, even

though individual rock surfaces on them might be dated as much younger than that -- as seen in the

recent paper on the Dartmoor tors (5) where individual slabs seem only to have been exposed to

cosmogenic bombardment for between 30,000 and 50,000 years.) We always need to bear in mind

that while a tor is being eroded by frost processes and gravitational settling -- and by other processes

too -- the surrounding landscape is also being eroded or lowered at a rate that may be equal, ormaybe faster and maybe slower!

We should bear in mind that tors at the end of the "preglacial" period were actually quite

widespread across North Pembrokeshire. There were tors on the uplands of Preseli, as mentioned

above. But they also occurred on Carningli and Dinas Mountain, at Carnedd Meibion Owen and

in Tycanol Wood, and in various locations in the Newport-Nevern area. There were also tors

further to the west, on the Pencaer Peninsula, on the St David's Peninsula, and at Poll Carn (Lion

Rock) and Maiden Castle at the northern end of Trefgarn Gorge in central Pembrokeshire. (We

need to be careful about the interpretation of some of these features, because some seem to have

been formed originally as islands or skerries when relative sea-level was falling from over 100m to

c30m above its present level. They are called "monadnocks" by geomorphologists. So marineprocesses, as well as chemical and other physical weathering processes, have been involved in their

creation.)

4

One of the tumbledown tors of Carn Meini. Here the bedrock is spotted dolerite. It has long been assumed that this

locality was the main source of the bluestones used at Stonehenge. The assumption has now been shown by geologiststo be incorrect.



2. Phase Two. Getting Colder.

At the beginning of the Pleistocene or Quaternary Ice Age, around 10 million years ago, the overall

distribution of upland and lowland in North Pembrokeshire, and the approximate position of the

coastline, were already determined (5). So in addition to the main features of Mynydd Preseli we

can be reasonably sure that there was a shallow depression on the northern flank of the mountain,with many small streams draining down into the Nevern Valley. The Brynberian valley would have

been a part of this drainage pattern. Were the deep river gorges at Rhosyfelin and Felin y Gigfran

present at the time? Probably not, since the whole land surface was probably higher. However, we

cannot rule out episodes of river downcutting and gorge development during phases of increased

precipitation and runoff, or during periods of low relative sea-level. (Remarkably little is known

about climate and landscape history during this period.) Were the tors at Carnedd Meibion Owen

and Rhosyfelin present at the time? Probably they were -- and maybe they were substantially larger

than those which we see today.

3. Phase Three. Ice here and there -- but mostly there.

In the period between 10 million yrs BP and 2.5 million yrs BP the climate cooled substantially, and

in some parts of the Northern Hemisphere -- in high latitudes and at high altitudes -- there must

have been intermittent glacial episodes, as shown in the deep-sea and ice sheet records (6). It is

doubtful that glacial ice will have affected West Wales and the South of England at this time -- so

probably there will have been a number of periglacial episodes some of which might have lasted for

hundreds of thousands of years. During these episodes frost shattering and scree development will

have occurred in some localities, and the landform details on tors and steep slopes might have been

modified. Generally, debris accumulation in the lower parts of the landscape (valleys and

depressions) will have occurred -- but if at certain stages there were periods of rapid snowmelt or

episodes of high rainfall, floods might have deepened valleys -- and it is possible that the Brynberianriver gorge, for example, might have begun to form at this time. Also, if some of these early glacial

episodes were large enough, it is possible that global sea-levels might have dropped to -30m or more,

leading to the inevitable incision of rock valleys well beneath present sea-level. The rock floor of

Milford Haven and all of the other coastal valleys of Pembrokeshire lies well beneath present sea-

level -- but we do not yet know whether this is because of many different episodes of deep

downcutting or because of just one or two, later in the Pleistocene (7).

4. Phase Four. Glaciation proper.

Around 2.5 million years ago, the first well-established glacial episode involving big ice sheets

affected the land masses of Western and Northern Europe. Some of the glacial deposits on thecontinental shelf seem to date from this time, but the

first episode to provide investigators with good

quality stratigraphic data was Anglian glaciation,

around 450,000 years ago. That was the most

intense and most prolonged glacial episode of the

Pleistocene, at least in Europe. There was a very

large British - Irish Ice Sheet, covering most of

Ireland, Scotland, Wales and England (8). So much

5

Global glacial and interglacial oscillations over the pastmillion years. The glacial phases shown did not all affectSW Britain or leave clear traces.



of the Planet's water was locked into

the big ice sheets that sea-level

dropped to at least -120m, meaning

that the ice streams and glaciers

were for the most part land-based,

flowing across vast expanses of landthat are now submerged beneath the

sea. That includes the floor of the

North Sea, the Irish Sea, Cardigan

Bay, St George's Channel and the

Celtic Sea.

These western areas bounded by

Ireland in the west and Great

Britain to the east were occupied by

the Irish Sea Glacier, the largest and

most powerful of all the ice streams

to have affected the British Isles (9).

As realised more than a century ago

by geologists like Geikie and Jehu, this glacier received most of its sustenance from the accumulation

areas on Ireland, NW England and Scotland, and flowed broadly southwards towards

Pembrokeshire before expanding into a great piedmont lobe which flowed SW, S, SE and even E.

The glacier also received ice flowing from the Welsh Ice Cap into Cardigan Bay -- and it is a fair

assumption that the surface of the glacier in St George's Channel must have been at around

2000m, sufficient to drive flowing ice across Preseli and the whole of Pembrokeshire, and up the

Bristol Channel towards the Mendips and the Somerset coast. There will also have been

supplements to the glacier from valley glaciers flowing broadly southwards in the valleys of SouthWales, from the uplands of the Brecon Beacons and the South Wales Coalfield. That "boost" might

well have been critical in maintaining the momentum of the Irish Sea Glacier, which was by now

more than 600 km away from its primary source areas.

What was the maximum southern extent of this glacier? Well, from the glacial traces in the

landscape and from the glacial deposits which we know about in southern England, we can be quite

sure that the ice affected Somerset, Devon and Cornwall. Were the uplands of the Mendips,

Exmoor, Dartmoor and Bodmin Moor covered at this time by local ice caps or by the big Irish Sea

Glacier? Almost certainly they were, since we know that in the Devensian glacial episode (peaking

around 20,000 years ago) there was an ice cap on Dartmoor, and an ice edge on the Scilly Isles. The

Anglian was a much more intense and extensive glaciation than the Devensian, and unless therewere as yet unexplained glaciological differences between the Anglian and Devensian glaciers --

expressed as different bed conditions, rates of ice flow and surface profiles -- it is reasonable to

6

One of the British-Irish ice sheet models prepared by Hubbard et al, 2008. Although this model was created for the Devensian glacial episode, it may be a goodindicator of the maximum extent of iceduring the Anglian glaciation. Note that

Cornwall, Devon, and Somerset are largelyice-covered, and that much of Wiltshire isalso submerged beneath ice.



assume that the ice actually reached Salisbury Plain. That assumption is not yet supported by

unequivocal stratigraphic evidence, but as discussed many times on this blog, there are traces of glacier icehaving affected the Somerset Levels, the Mendips, and the Bath area -- and if we accept (as I do) that the

Stonehenge bluestones and other strange stones found on Salisbury Plain are extremely old glacial

erratics, the matter is more or less settled. On the principle of Occam's Razor, we do not need any

other explanation relating to the transport of the bluestones.

What about Rhosyfelin? I suggest that when the Anglian ice started to impinge upon the coastal

strip of North Pembrokeshire, there was a substantial tor or craggy outcrop at Rhosyfelin, standing

prominently above an undulating fluvial landscape which had already been affected to some degree

by a prolonged period of periglacial conditions. That is the way it is, prior to all big glacial

episodes. We cannot know whether the tor was massive and coherent, or just a pile of tumbledown

debris. At any rate, when the Irish Sea Glacier had taken possession of the northern slopes of

Preseli and started to flow rapidly across this landscape, conditions were perfect for shearing to

occur within the ice (10), and for the entrainment of bedrock blocks up into the body of the glacier,

and for transport within the glacier away towards the SE and E. Many of the other tors on the

northern flank and summit of

Preseli will have been similarly

affected, while areas on the

southern flank will have been

affected to a much lesser extent,

as explained in other posts on this

blog. It may be that hundreds or

thousands of tonnes of rock were

removed from the Rhosyfelin

rhyolitic outcrop in this way.Because the rock is fissile and

flaky, and broken up by abundant

fissures or joints, the chances of big

slabs or blocks of this rhyolite being transported all of the way to Salisbury Plain without further

damage were not great -- but not impossible. The bulk of transported material will have been in the

form of boulders and cobbles maybe less than 1m in diameter. Most of it will have been dissipated

or ground up in downstream glacial deposits, but some slabs and "orthostats" in protected locations

within the ice mass could have been transported for 300km or more without further damage, to be

melted out or dumped in due course at the ice edge. I have speculated on this blog that the

"entrainment episode" at Rhosyfelin might have been quite short-lived (maybe lasting for just a few

decades or centuries) and that for the rest of the glacial episode the site was protected by immobile

or very sluggish cold-based ice. (As a general rule, warm-based glaciers with their bases at or near

7

A mechanism for the entrainment ofblocks and other debris from locationson the northern flank of Preseli duringthe waxing phase of the Anglian

Glaciation. This phase may not havelasted for very long; at the peak of the

glacial episode the landscape at Rhosyfelin might have been protected from glacial erosional processes.



the pressure melting point can flow fast and erode effectively, whereas cold-based glaciers tend to be

frozen to their beds and are incapable of much "work" in changing the form of the land surface.)

At the end of the Anglian glacial episode, it's reasonable to suppose that the Irish Sea Glacier

wasted catastrophically. The meltwater channel complex of the Gwaun-Jordanston area was

probably formed at this time, with huge volumes of meltwater escaping southwards across any low

cols that were available, or else being forced to flow south-westwards and then southwards deepbeneath the wasting ice surface or actually along the ice edge. Initially, much of the meltwater was

flowing subglacially under high pressure, meaning that occasionally it was actually flowing uphill (9).

The valleys connected to Cwm Gwaun are classics of their kind, frequently cited in text books and

recognized in the SSSI citations which guarantee a degree of extra landscape protection within the

Pembrokeshire Coast National Park. Was there a glacial lake impounded against the northern face

of Preseli at this time? It's possible, but as yet we do not have stratigraphic evidence which can be

brought to bear. But the gorge at Rhosyfelin may well have had its origins at this time, as great

volumes of meltwater flowed northwards towards the lower land of Cardigan Bay at a time of

chaotic ice wastage -- such as we see on the margins of some Icelandic and Greenland glaciers

today.

5. Phase Five. Many Missing Millennia.

Following the Anglian Glaciation, over the course of more than 350,000 years, there were several

glacial and interglacial cycles, and it is possible that glacier ice might have affected Rhosyfelin on

more than one occasion. This ice might have come from the north in the form of another Irish Sea

Glacier, or it might have come from a small Preseli ice cap, formed as a result of localised extreme

cold and high snowfall. We really have no local evidence which we can -- at this stage -- interpret

sensibly. But during this long period there may well have been other climatic episodes at least as

warm as the present interglacial, and other very prolonged episodes of periglacial conditions with or

without continuous permafrost. Over a period as long as this, it is inevitable that Craig Rhosyfelinwill have undergone further substantial change, involving the ongoing reduction of the rocky tor

and the accumulation of debris around its foot and in the river valley adjacent to it. What about the

details of the river valley? They are actually quite complicated here -- and particularly notable are

the subsidiary valleys or gullies on either side of the craggy ridge which we see today. They suggest

that water has at some stage (or stages) flowed down from the valley side into the gorge, maybe

excavating out zones of weakness coinciding with faulted or brecciated zones, or maybe coinciding

with the junctions between the rhyolites and the adjacent sedimentary rocks.

6. Phase Six. The Last Interglacial.

Thus far, we have no evidence of either the climate or the process of sedimentation at Rhosyfelinfor the period around 100,000 - 70,000 yrs BP. However, there are abundant signs on the coast that

at some stage during this interglacial (called the Ipswichian) relative sea-level was higher than it is

today, by at least a couple of metres. There are not only raised beach platforms cut across bedrock

in many coastal locations, but also raised beach deposits of rounded cobbles, sand and gravels --

sometimes cemented into a hard conglomerate by calcium carbonate and sometimes stained heavily

with iron and manganese oxides. The climate was warmer than it is today, with a landscape just as

richly clothed with vegetation (11). It may be that Mynydd Presely would have been quite heavily

wooded, in spite of the high exposure and the location in the far west of Wales.

Soil development during the interglacial would have been much more prolonged than that of the

present interglacial -- so soil horizons maybe 2m thick would have been commonplace. But in

North Pembrokeshire, the chances of any such soil horizons surviving the events of the following

Devensian are very slim indeed.

8



7. Phase Seven. The Devensian Glacial Episode.

This episode is conventionally considered to have started around 70,000 years ago and to have run

until about 10,000 years ago (12). Now we are getting into the period which we might expect to be

represented in the sedimentary sequence at Rhosyfelin. Prior to the arrival of the Devensian ice in

this area, there was a long period (maybe 50,000 years) of oscillating periglacial climate. For partsof this period there was continuous permafrost, as indicated by occasional traces of patterned

ground including fossil ice wedges and cryoturbation features. When at last the ice of the Irish Sea

Glacier did arrive in North Pembrokeshire it created an effective ice dam along the coastline,

holding up the drainage of north-flowing rivers and streams on the northern flanks of Mynydd

Preseli and leading to the creation of ice-dammed lakes in the Teifi Valley (now well documented in

a sequence of laminated lake sediments more than 50m thick in places) and maybe in other valleys

as well (13). Various researchers have suggested a series of glacial lake overflows across low-lying

cols, leading to the creation of "overflow channels" or spillways -- but the precise sequence of events

is still a matter for debate, and much more evidence of glacial lake sediments is needed before the

true story can be told. In this blog we have had some debate on the question of whether there was a

"Glacial Lake Brynberian". If it ever did exist, then the site of Craig Rhosyfelin might well have

been submerged beneath the waters. And if there are laminated or varved lake clays to be found

anywhere, then they might be found on the floor of the valley adjacent to the site being excavated

by Prof Mike Parker Pearson and his team.

9

A conservative assessment of the Devensian ice edge in North Pembrokeshire, based on the most recent GeologicalSurvey map. Evidence is accumulating to show that the ice of the Irish Sea Glacier was more extensive than this,

probably flowing across the whole of the Carningli upland and maybe across the eastern end of the Preseli ridge aswell.



I am now convinced that the Irish Sea Glacier pushed further south than Rhosyfelin and pressed

against the northern hillslope of Preseli. I am also convinced that the ice flowed across Carningli,

maybe even covering the highest crags, and across Tycanol Wood and the tors of Carnedd Meibion

Owen. There are fresh-looking glaciated slabs in many locations, and I think it possible that the ice

might even have inundated the highest tors including Carn Meini. More work needs to be done on

this, and maybe we will need cosmogenic dating to be employed in order to answer the question of

maximum Devensian ice extent. There may have been several pulses or ice advances within a shortperiod, and as evidence for this I would cite the recently discovered morainic accumulations at

Gernos Fawr, Cilgwyn and Pont Ceunant.

So what traces of the Devensian glaciation might we expect to find at Rhosyfelin? Well, one thing

we know from a long study of the coastal exposures of Ice Age deposits around the Pembrokeshire

coast is that the glacial episode was neither long enough in duration not intense enough to erode

away all of the older sediments overriden by the glacier. The "lower head" accumulations of frost-

shattered and pseudo-bedded slope deposits may have been partly removed, but plenty of them still

exist. So we can assume that they remained deeply frozen and reasonably resistant to erosion by the

glacier that came in from the north and north-west -- or maybe at some stage from the north-east as

well. We can discount the effects of the short-lived Preseli ice cap which might have occupied the

highest parts of Preseli at some stage. That would have been cold-based, thin and almost stagnant,

with a very limited capacity for affecting landscape change.

If the ice was capable of streaming across bedrock surfaces and polishing or moulding them, it must

also have been capable of some destruction of upstanding craggy outcrops such as that of Craig

Rhosyfelin. So delicate crags might have been demolished, rubble might have been moved and

maybe dragged away to other locations further south, and a great deal of debris from pre-existing

scree banks might well have been incorporated into the basal ice material derived from country

already overridden.

We might expect that in particularly favourable locations within the valleys of Afon Nyfer and Afon

Brynberian, we might find a sequence of periglacial deposits with lake deposits above them, and

with glacial deposits higher still in the sequence. These deposits will be sedimentologically quite

distinct from one another -- and will thus be easy to recognize.

From what I have seen thus far of the excavations at Rhosyfelin, I suspect that at the end of the

2012 digging season the archaeologists reached the top of a till layer which incorporates much local

material derived from the immediate vicinity. In this regard it will have been very similar to the till

found all over the land surface of the Newport - Nevern area. Where rhyolites are outcropping,

there are rhyolite boulders in the till; where dolerites are outcropping, the boulders and coarse

debris are of dolerite, set in a matrix of debris largely derived from soft and flaky Ordovician shalesand slates.

Back to the details for Rhosyfelin. It seems to me that on the exposed rock face we have a series of

glaciated slabs coinciding with a fracture plane -- maybe along a fault line. The broken debris piled

up along the base of this face is mostly angular or sharp-edged, but it includes slabs and stones

which have been smoothed by erosion, with many sharp edges and corners rounded off. That seems

to suggest glacial action or else a short-lived episode of fluvio-glacial activity, with torrents of

meltwater flowing down the gully and into the river valley proper. (I'll reserve judgment on that one,

until we can see -- maybe in the final excavation report -- whether there are any fluvioglacial

deposits in the stratigraphic sequence, downslope from the excavation site.) As indicated in some of

my earlier posts, it seems that the "2012 surface" exposed by the archaeologists coincides with the

top of a layer of mixed rubble and till, with signs of iron staining and weathering. This iron pan or

hard pan is common throughout the Preseli uplands area, and the top of it has no archaeological

10



significance. The till exposed at Rhosyfelin appears to be clay-rich, like many of the other tills in

North Pembrokeshire. To me, the colouring indicates a period of sub-arial exposure prior to the

accumulation of relatively fine-grained slope deposits on top of the boulder litter. On the other

hand, iron-staining and weathering can occur in the top 50cm of a clay-rich till layer even when it is

buried beneath other sediments which permit easy water percolation. (This can be seen in the cliff

section at Abermawr.)

11

Above: The foxy red hardpan herecoinciding with the top of the

Rhosyfelin till layer. Note theincorporated erratics of dolerite and

other stone types. The erratics are generally smoothed and have theiredges rounded off by ice action.

Right: Other erratic boulders andstones extracted from the dig duringSeptember 2013. These are mixedhere with slabs of local rhyoliteremoved from the dig site.



In the 2013 digging season the archaeologists excavated well into this till layer and revealed the

presence of many sub-rounded and sub-angular stones and boulders made of rhyolite, dolerite and

other “exotic” stone types. Its thickness is variable, as one would expect. Striae are difficult to pick

up on these rock types, but I found one broken bedrock slab with clear crescentic gouges on its

surface, suggesting heavy ice movement across this site.

The Rhosyfelin scree / rubble layer which has

been interpreted as quarrying rubble by

Professor MPP and his colleagues (for reasons

best known to themselves) rests against the base

of the rock face. When did this scree start toaccumulate, and when did accumulation come

to an end? As indicated above, it is possible that

some of the broken debris has been in position

since the end of the Anglian glacial episode around 450,000 years ago, when the Irish Sea glacier

disintegrated. If we bring our understanding of glacial episodes to bear, we may assume that there

were periglacial episodes which followed the melting of the glacier ice, leading to the breakdown of

glacially steepened slopes and the accumulation of scree and other slope deposits. There may have

been no further glacial action in this area until the Devensian; there was at least one other glacial

phase (referred to as the Wolstonian or Saalian glaciation in other parts of the world) but if the Irish

Sea Glacier of that time did not extend this far south, then there would have been a prolongedperiod of cold or periglacial conditions (maybe lasting for 50,000 years or more) during which

further breakdown of the Rhosyfelin crags might have occurred. Whether the rock debris fell from

above the rock face as we see it today, or from the face itself, we cannot tell on the basis of the

current evidence.

When the Devensian ice arrived there would have been a great deal of debris around the Rhosyfelin

"spur" -- some of it fresh and some of it having been in place for maybe hundreds of thousands of

years. One would expect the oldest material on the site to be stained with iron and manganese

oxide. As the ice flowed across the site, some material will have been overridden in a relatively

undisturbed state, some incorporated into the basal layers of ice and transported away, and some

mixed up with basal till and erratics transported from the land surface to the north of the site.

8. Phase Eight. The Late-Glacial.

Probably this site was clear of glacier ice by 18,000 yrs BP. After that, for maybe 6,000 years, the

climate remained cold as the great ice sheets gradually wasted away further to the north. We know

from the stratigraphic evidence in other parts of Pembrokeshire that there was some redistribution

of glacial and other old deposits by solifiuxion and slope washing processes, but there were no thick

accumulations of "head" as there were in the earlier part of the Devensian (14). But in the period

13,000 yrs BP to 10,000 yrs BP there was a strange "triple event" referred to as the "Late Gacial"

and characterised as a cold phase (Zone 1 or Older Dryas), a warmer interlude (Zone 2 or Allerod)

and another cold phase (Zone 3 or Younger Dryas). There is still much debate about whether these

three episodes are recognizable across the world, or whether they were localised within NW Europe

for reasons that are not yet apparent (15). At any rate, they do seem to appear in the Pembrokeshire

12

Crescentic gouges on a flattish slab of foliated rhyolite,suggesting that this slab has been subjected to intense

pressure by thick over-riding ice.



record from other Pleistocene sites, and we can surmise that there were further rockfalls onto the

Devensian till surface at Rhosyfelin during the Older Dryas and Younger Dryas, accompanied by

solifluxion of broken rock materials from the hillslope on the other side of the gully.

The lowest layer above the till surface at Rhosyfelin is a dark-coloured and fine-grained bed up to

30 cms thick, with many stony and gravelly inclusions and "streaky" bands which appear to be rich

in organic material. This mightbe a lacus t r ine depos i t

accumulated during a glacial

wastage phase, either in a

localised small lake within the

bounds of the valley or in a

more extensive "Glacial Lake

B r y n b e r i a n " i m p o u n d e d

between a retreating ice edge

and the northern slope of

Mynydd Preseli. There is at

least one small feature that

looks like a fault; and less than a

metre away there is something

that looks like a small fossil ice

wedge indicative of permafrost.

In places there are traces of

what appear to be involutions

or cryoturbation features; they

need close examination, for they

may also have originated as

" l oad ing d i s t o r t i ons" o rinjection features resulting from

t h e c o m p r e s s i o n a n d

disturbance of saturated

sediments by materials dumped on top of them. This dark-coloured layer has a sharp upper

surface, and above it is a brown stony layer full of angular broken debris. Maybe this is frost-

shattered material, and maybe not; exposed crags and even rocky outcrops on hillsides break down

in this way, with angular fragments being worked from the eroding face by a wide range of

processes including root expansion, pressure release, rockfalls and small landslides in periods of

exceptional rainfall.

9. Phase Nine. The Holocene Interglacial.

When the Younger Dryas ended quite abruptly, the last small glaciers to have survived in the

uplands of Britain all disappeared. The climate warmed rapidly, and from this point on, for the last

10,000 years or so, the dominant processes on most slopes (including those at Rhosyfelin) have been

related to solifluxion under a temperate climatic regime. In the exposures on the flanks of the

archaeological dig we can see what appear to be up to six distinct layers -- some with a darker

colouring reminiscent of organic-rich soil layers, and others with a buff or foxy brown colour. The

darker layers seem to have a greater proportion of silts and clays in them, and the brown layers have

more in the sand and gravel fractions. But the layers are discontinuous, which means that we should

perhaps refer to "pseudo-bedding" rather than bedding.

What is the climatic significance of these "layers"? Well, we know that there were climatic

oscillations on a small scale during the British Holocene, although correlations across the rest of

13

Six distinct layers exposed during the 2012 dig. The three darker colouredlayers might incorporate organic materials. In the lower dark layer (which

has been sampled) there seem to be permafrost structures includinginvolutions, a small fault and a fossil ice wedge.



Western Europe are difficult. These episodes are referred to as the Pre-Boreal, Boreal, Atlantic

(also referred to as the "Climatic Optimum"), Sub Boreal and Sub Atlantic periods. The warmest

episode (Hypsithermal) seems to have been around 8,000 to 6,000 years BP, and after that, in the

episode sometimes referred to as the "Neoglacial" by glaciologists, there were a number of short

episodes cold enough for glacier advances in the uplands of the Alps, Norway and Iceland. Around

5,000 years BP, when the earliest phases of Stonehenge were being built, the climate seems to have

been cool and rather wet, but with a slow reduction in rainfall totals over 2,000 years or so.

It may well be that when radiocarbon and other dating has been completed for the layers exposed in

the Rhosyfelin digging seasons of 2011-2014, a reasonably accurate timescale may be applied to the

six (or more!) "layers" -- but for the time being we simply have to say that within the last 10,000

years slope deposits up to 2m thick have accumulated on top of the broken rock debris, as the gullies

on the flank of the rhyolite ridge have been gradually filled with the products of ongoing erosion

and accumulation. Personally, I would not be too surprised if these sediments were to be found to

contain Mesolithic flint flakes or microliths made from the Rhosyfelin rhyolite raw materials. In

exceptionally wet periods there may even have been mudflows and slope collapses leading to the

redistribution of soil and rock debris -- helping to explain why some apparent "layers" are

discontinuous. Not all of the rock debris was covered with later solifluxion or slope deposits; close to

the rock face many blocks were visible sticking up through the ground surface, or were covered by

thick vegetation but not soil. The highest part of the "abandoned orthostat" was only about 20 cm

beneath the ground surface when found by the 2011 excavation team.

10. Phase Ten. Human Interference?

Leaving aside for the moment the assumption that all of the rock debris at Rhosyfelin is "quarrying

debris" resulting from Neolithic stone extraction activities, the archaeologists have mentioned several

features that supposedly demonstrate human interference in the arrangement of stones and

superficial deposits:

(a) At least two rounded stones referred to as hammerstones, supposedly used for the shaping of

rhyolite orthostats. According to Professor MPP, these stones have percussion fractures and other

damage on their surfaces, showing that they have been used for striking against softer rock surfaces

so as to remove projections or irregularities. Apparently these "hammerstones" have been found

among the broken rhyolite rock debris low in the sequence described above. I have not examined

these "hammerstones", and so I reserve judgment on whether any surface markings are natural or

man-made. (My guess is that they are most likely to be fractures, scratches and chatter-marks typical

of erratic stones dragged along on the bed of a glacier -- and indeed there are other rounded and

sub-rounded erratics as well, including at least two made of quartz, scattered in the rhyolite rock

debris and described in earlier posts on this blog.)

(b) The so-called "rhyolite orthostat" lying some 5m from the rock face, with its upper surface just

20 cm beneath the ground surface at the onset of excavation. This elongated slab has caused great

excitement, and has been much photographed as "the bluestone which was left behind" by the

Neolithic quarrymen. Its dimensions, according to the archaeologists, make it a good candidate for

recognition as an ideal Stonehenge bluestone; and they are also quite convinced that it has been

shaped. They also argue that it is too far from the rock face to have reached its final resting place

naturally. On the other hand, I am not the only observer to have suggested that it looks entirely

natural, and that its position is not at all exceptional, lying as it does within the "apron" of broken

rock debris beneath the Rhosyfelin crags. It lies on top of other smaller blocks, suggesting that it

was emplaced by a more recent rockfall from high up on the adjacent crag. I can see no evidence

on the stone of any working with hammerstones or other tools.

14



15

Another photo of the “abandoned orthostat” at Rhosyfelin; this was taken in 2011. It shows how foliated, flaky and fractured the rhyolite is here -- giving rise to speculation that it was never very suitable for local standing stones, letalone for long-distance transport. The stone rests on a great deal of rock rubble. We do not know how much rockrubble was resting on top of it.............

Two photos showing the “abandoned orthostat” and the rock face at Rhosyfelin. The one on the left is from 2011 andthe one on the right is from 2012. We can see that some of the fallen rock debris is deeply covered by fine-grainedslope deposits and some broken blocks are hardly covered at all -- with some sharp edges projecting through the ground

surface.



(c) A number of long thin stones with "worn surfaces" which according to Prof MPP have been

used as "railway tracks" along which the "orthostat" has been dragged away from the rock face.

MPP says that some of these elongated stones are still positioned beneath the orthostat,

demonstrating that the Neolithic quarrymen were in the process of dragging the stone even further

away from the face when the project -- for some reason or other -- was suddenly abandoned. The

diggers of 2012 also found fragments of "railway track" stones which had supposedly been broken

during the dragging of the "orthostat" across them; and some of these bits were joined togetheragain on the grass for all to admire. I am not alone in considering all of this to be fanciful in the

extreme. There are elongated stones everywhere amid the broken rock debris, and most of these

long stones are not "conveniently arranged" at all. There are broken stones everywhere, and if one

was keen enough one could probably reassemble many of them. The wear on the edges and flat

surfaces of the "railway track" stones is no greater that that on many other stones scattered amid the

scree material. Interestingly, in the 2013 digging season the “railway tracks” were removed, and

were not mentioned in Prof MPP’s Moylgrove lecture.

(d) A "stone hole" near the tip of the

Rhosyfelin rocky spur, and excavated into

the reddish-brown "floor" of the 2012

excavation. It is quite a dramatic feature,

almost circular, and about 1m across and

60 cm deep. We have to assume that it is a

real feature, and not an "excavation

artifice." Did it at one time hold a

standing stone or a massive timber pole?

Did it have ritual significance? Or was it something intended for storing food or other items? Could

it have been a burial pit? We have no way of knowing more about the use of the pit until further

information is forthcoming from the archaeologists. However, one feature that interests me is the

occurrence of quite large angular stones in the sides and on the bottom of the pit, indicating that

the stone litter at Rhosyfelin does not sit on top of the "floor" but passes beneath it. The significance

of this will be discussed in the following paragraphs. Also, because of these stone projections any

standing stone or wooden post set into the hole must have had a much smaller diameter than the pit

itself.

(e) Between the "stone socket" and the rocky outcrop near the tip of the spur there is a burnt

surface or camping floor which suggests, according to Prof MPP, occupation of this site during the

Iron Age. The archaeologists might well have taken charcoal or other organic materials for

radiocarbon dating. According to the Brynberian presentations on 18 September 2012, the traces

of occupation tie in with the stone socket, although the evidence underpinning that statement was

not enunciated. No doubt some attention will be given to the history of Iron Age occupation during

the 2013 and 2014 digging seasons. As I have stated before on this blog, it is not at all surprising

that a site such as this might have been used for many years by hunters and travellers, given that the

location lies in a well wooded river valley suitable for hunting and fishing, close to a point where the

river could easily be forded even at times of high river flow. Also, the gully on the flank of theRhosyfelin spur would have afforded protection from wind and rain; and indeed a simple shelter

could have been built against the rock face. We await developments on this matter.

16

The socket or “stone hole” at Rhosyfelin. Note

that rock rubble is seen in the base and sides of the pit, beneath the Iron Age (?) ground surface seen inthe photo.



(f) In his talks Professor MPP has referred to “ghosts” or precise locations in cracks or crevices on

the Rhosyfelin rock face from which recognisable elongated stones in the “stone litter” have been

“taken”. I have examined the rock face and see no evidence whatsoever to support this contention.

(g) In his 2013 lecture at Moylgrove, Professor MPP showed a slide of a small vertical stone

embedded in the ground. It looked perfectly natural to a geomorphologist, but he claimed that this

stone and others were deliberately set into the ground as pivots so that bigger stones could be moved

across them by the use of levers. He also claimed that scratches or striations on a smaller transverse

stone just beyond the downslope tip of the big monolith had nothing to do with fractures or

foliations, or with ice action. So he concluded that the scratches must have been made by one or

more big orthostats being dragged across it from the inner depths of the quarry, further upslope.

However, examination of this transverse stone shows that the marks are not striations, scratches or

erosional grooves. They are outcropping foliations on the rock surface, no different from those on

scores of other stones to be found throughout the dig site. They follow the strike of these micro-

structures. Examination of the side of the rock shows that the foliations or "pseudo-layers" run

within the rock, downwards towards the bottom left of the photo at the top of the next page.

(h) One gets the impression from the archaeologists that there is a clearly defined surface or “quarry

floor” on which quarrying activities were carried on during the Neolithic. This “floor” has a greater

clay content than the layers above it, and in has a reddish colour which marks it out from the buff,

brown and black colours of the sediments above it. I am quite convinced that this “floor” is an

artifice, invented by the archaeologists. As indicated above, it looks to me like a perfectly typical iron

pan or hardpan with gleyed till of boulder clay beneath it. Many stones, slabs and boulders rest

above this hardpan layer; others are beneath it, and others project through it.

17

The location of the “camp site” at Rhosyfelin, between the outer end of the rock face and the pit, which can be seen inthe foreground.



DISCUSSION

This site is fascinating from a geomorphological standpoint because the archaeological dig has

revealed a number of features that can be tied in with the known landscape history of North

Pembrokeshire. There are many coastal exposures of Pleistocene deposits which can be used to

elucidate a complex sequence of events; but there are relatively few inland exposures which reveal a

matching stratigraphy. Indeed, the stratigraphy at Rhosyfelin does not match that of Abermawr (forexample) in great detail. Nonetheless, we know from comparable exposures that slope deposits

incorporating frost-shattered debris take a very long time to accumulate in this environment -- at a

rate of maybe one or two metres per 10,000 years in a periglacial climate. (Much faster rates of

accumulation are found beneath steep cliffs made of friable rocks including shales and mudstones.)

Thus I would be very surprised indeed if all of the material accumulated above the "broken rock

apron" at Rhosyfelin had accumulated in a temperate climate over no more than 5,000 years

(basing that date upon the assumed time of rock quarrying and stone transport to Stonehenge, using

the archaeologists' own chronology.) If such short-term accumulation did occur, where are all the

other deposits from the 15,000 years between 20,000 BP and 5,000 BP?

Another fact which suggests accumulation of these post-glacial layers over a long period of time(maybe 20,000 years) is the alternation of various layers (or pseudo-layers) of different colours and

textures. It is easiest to explain these by reference to a history of periglacial warming -- namely cold

snap -- temporary warming -- colder snap -- final warming in the Holocene or post-glacial period.

If we seek to explain these changes or oscillations in sedimentation by reference to the very subtle

changes that have occurred over the past five millennia, all sorts of difficulties emerge.

If we assume (for the sake of argument) that the slope deposits that have come from the rising

ground to the NW, W and SW of the dig site had started to accumulate prior to the onset of

quarrying activity, one would expect major disruptions in sedimentation to have occurred, with the

quarrymen using a cleared "floor" which would then have been covered by sediments following the

cessation of quarrying activity. Only those involved in the dig will know whether such a break or

unconformity in sedimentation has been observed; but I suspect, from an examination of all the

18

Close-up of the "grooves" supposedlycaused by heavy orthostats being draggedacross the stone in question. There areindeed grooves, but they coincide exactlywith the outcropping foliations on the

stone surface.

They are perfectly normalweathering phenomena, of no significancewhatsoever to the quarrying debate.



photos available from 2011 and 2012, that the sediments removed down to the 2012 excavation

"floor" had accumulated in an unbroken sequence over a very long period of time.

My conclusion, from the evidence currently available to me, is that all of the features at Rhosyfelin,

with the possible exception of the Iron Age "camp site" and the strange pit located nearby, can be

explained by natural processes operating over many thousands of years -- possibly hundreds of

thousands of years. When I look at the broken rock litter, and even at the famous "abandonedorthostat", I see no signs of quarrying or any other human activity.

That having been said, there are a number of interesting features of the site which require further

investigation and discussion. For a start, the Iron Age camp site near the tip of the spur (near the

outer edge of the slope deposits) seems to have been covered with later sediments up to 50 cm thick;

these must have accumulated in the past 2,500 years or so. Do these sediments match the sediments

at the top of the sequence further upslope, or are they distinguishable in some way? Do these

deposits comprise more sandy, silty and clay material, as might be expected from relatively recent

hillwash processes at the bottom end of a long slope? Hopefully, the site report, when published,

will give guidance on this.

There are two alternative scenarios that might resolve the debate about whether there ever was a

Neolithic quarry at Rhosyfelin. If there was a discrete episode of rock removal, with human beings

levering down slabs of rock from a favourable rocky crag or ridge, we might expect the pre-

Neolithic land surface to pass beneath all of the rock debris. In other words, the "apron" of rock

rubble and slabs -- including the "abandoned orthostat" -- should rest on a discernible surface of till

or other material which might be in contact with a buried part of the rock face. If such an

unconformity does NOT exist, then the likelihood of there ever having been a quarry here is much

reduced. On the other hand, if the rock rubble passes well down beneath the surface exposed in the

2012 excavation, that means that there has been a long history of rockfalls and debris accumulation

along the lines described above. Perhaps, during the course of the latest dig, an answer will befound to this question.........

Finally, we must consider another anomaly. If the Iron Age "camp site" has been correctly

identified and dated, that means that the ground surface which we can see in the photos dates from

around 2,500 yrs BP. This surface seems to pass BENEATH the big "abandoned orthostat" which

has caused so much excitement. That means that the orthostat was emplaced later than the Iron

Age, possibly as a result of a spectacular rockfall from one of the higher crags on the rocks ridge.

On the other hand the Neolithic ground surface on which our hypothetical quarrymen worked must

be LOWER in the sequence than the Iron Age surface, making the archaeological "quarrying

hypothesis" even more difficult to accept.

These notes are provided in a spirit of enquiry, to encourage academic debate and perhaps to feed

into the discussions surrounding the 2013 and 2014 digs. I have provided a working hypothesis

which can be shot down in flames, or else modified dramatically through new discoveries. No

working hypothesis survives for very long, and I anticipate that this one will be no different.

Whatever the outcome of the researches at Rhosyfelin may be, it is certainly a fascinating site.

Whether its ultimate significance is geomorphological or archaeological remains to be seen.

Finally, a couple of pleas to Prof MPP and the other archaeologists. When are we going to see your

site reports? And when are we going to see the colour of your evidence? With the completion of

four annual digging seasons, we have seen nothing, and have heard nothing apart from rumours

about “inconvenient” radiocarbon dates. You have made some pretty dramatic claims for

Rhosyfelin, but thus far we have not seen any published photos of the hammerstones, of the flints

and flakes which (according to some diggers) have been found, or of the hard evidence for Iron Age

19



occupation. There are many people who would like to know how hard your evidence actually is,

and who would like to work out for themselves whether this really is a site worth enthusing about.

REFERENCES

(1) Stonehenge and the Ice Agehttp://brian-mountainman.blogspot.com/

There are also interesting discussions on other sites such as The Megalithic Portal.

http://www.megalithic.co.uk

(2) Ixer, RA and Bevins RE. 2011. Craig Rhos-y-felin, Pont Saeson is the dominant source of

the Stonehenge rhyolitic ‘debitage’. Archaeology in Wales 50, 21-31.

Ixer, RA and Bevins RE, with a contrib from Pitts, M. 2013. A re-examination of rhyolitic

bluestone ‘debitage’ from the Heelstone and other areas within the Stonehenge Landscape. Wilts

Archaeol and Nat Hist Mag, 106 (2013), pp 1-15Richard E. Bevins, Rob A. Ixer, Peter C. Webb, John S. Watson. 2012. Provenancing the rhyolitic

and dacitic components of the Stonehenge landscape bluestone lithology: new petrographical and

geochemical evidence. Journal of Archaeological Science 39 (2012) 1005e1019

Ixer, R.A and Bevins, R.E. 2013. Chips off the old block: the Stonehenge debitage dilemma.

Archaeology in Wales 52, 11-22.

(3) Mike Parker Pearson. Stonehenge: exploring the greatest Stone Age Mystery, 2012,

Simon and Schuster, 416 pp

http://brian-mountainman.blogspot.co.uk/2014/08/review-of-mike-parker-pearsons-2012-

book.html.

(4) Bevins, R E, 1982. Petrology and geochemistry of the Fishguard Volcanic Complex, Wales.

Geological Journal, Vol.17 (1), p.1-21.

Howells, M.F. 2007 British Regional Geology: Wales. British Geological Survey 230pp

(5) Yanni Gunnell, David Jarman, Régis Braucher, Marc Calvet, Magali Delmas, Laetitia Leanni,

Didier Bourlès, Maurice Arnold, Georges Aumaître, Karim Keddaouche. 2012. The granite tors of

Dartmoor, Southwest England: rapid and recent emergence revealed by Late Pleistocene

cosmogenic apparent exposure ages. Quaternary Science Reviews 61 (2013) 62e76

(5) Brian John 2012. Pembrokeshire Coast Path. Official National Trail Guide, Aurum/Natural

England/CCW, 165 pp.

(6) Mangerud, J.; Ehlers, J.; Gibbard, P., ed. (2004). Quaternary Glaciations : Extent andChronology 1: Part I Europe. Amsterdam: Elsevier, 488 pp..

(7) Tooley, MJ and Shennan, I (eds) Sea-Level Changes (Institute of British Geographers Special

Publications) 1987, 416 pp.

(8) Mangerud, J.; Ehlers, J.; Gibbard, P., ed. (2004). Quaternary Glaciations : Extent andChronology 1: Part I Europe. Amsterdam: Elsevier, 488 pp..

The Glacial History of the British Isles during the Early and Middle Pleistocene: Implications forthe long-term development of the British Ice Sheet. 2011. Jonathan R. Lee, James Rose, Richard

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http://books.google.com/books?id=mmPwAAAAMAAJ

http://www.megalithic.co.uk/











http://brian-mountainman.blogspot.com/

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J.O Hamblin, Brian S.P. Moorlock, James B. Riding, Emrys Phillips, Rene " W. Barendregt and Ian

Candy. Developments in Quaternary Science. Vol. 15, Ch 6, doi: 10.1016/4

(9) Brian John 2008. The Bluestone Enigma. Greencroft Books, 160 pp.

Brian John, 1970. In Lewis,CA (ed) “Pembrokeshire” in The Glaciations of Wales and Adjoining Regions, Longman, 378 pp.

(10) “Stonehenge’s Mysterious Stones”, Brian John and Lionel Jackson, Earth Magazine,

December 2008. http://www.earthmagazine.org/article/stonehenges-mysterious-stones

(11) JJ Lowe and MJC Walker, Reconstructing Quaternary environments (second edition)

Addison Wesley Longman Limited, Harlow. 1997. 468 pp.

(12) Dynamic cycles, ice streams and their impact on the extent, chronology and deglaciation of the

British–Irish ice sheet. online 2008. Alun Hubbard, Tom Bradwell, Nicholas Golledge, Adrian

Hall, Henry Patton, David Sugden, Rhys Cooper, Martyn Stoker. Quaternary ScienceReviews 28 (2009) 759–777.

Evans, D.J.A. and Clark, C.D. and Mitchell, W.A. (2005) The last British Ice Sheet: A review of the

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(13) Palaeoenvironmental interpretation of an ice-contact glacial lake succession: an example from

the late Devensian of southwest Wales, UK. James L. Etienne, Krister N. Jansson, Neil F. Glasser,

Michael J. Hambrey, Jeremy R. Davies, Richard A. Waters, Alex J. Maltman and Philip R. Wilby,

Quaternary Science Reviews, Volume 25, Issues 7-8, April 2006, Pages 739-762

(14) The Devensian/Weichselian Late-glacial in northwest Europe (Ireland, Britain, north Belgium,

The Netherlands, northwest Germany), M. J. C. Walker, S. J. P. Bohncke, G. R. Coope, M.O'Connell, H. Usinger, C. Verbruggen. Journal of Quaternary Science, Volume 9, Issue 2,

pages 109–118, June 1994.

(15) The glaciation of Dartmoor: the southernmost independent Pleistocene ice cap in the British

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Manuscript revised 15th September 2014

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Documents

A Long History of Rhosyfelin (revised)