Some of the ideas discussed in this blog are published in my book called "The Bluestone Enigma" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
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Wednesday, 30 April 2014

The Stonehenge Letters

Well, this looks interesting.  It's a novel -- or is it?   Probably not very scientific, but everything in its place......

The Stonehenge Letters

ISBN-10: 1552452948
ISBN-13: 9781552452943
256 pp, Paperback
Apr 13 2014

Harry Karlinsky
Note: This title is now also available as a digital eBook.

While researching why Freud failed to win a Nobel Prize at the Nobel Archives in Sweden, a psychiatrist makes an unusual discovery. Among the piles of papers in the 'Crackpot' file are letters addressed to the executor of Alfred Nobel's will, written by several notable Nobel laureates — including Rudyard Kipling and Marie Curie — each offering an explanation of why and how Stonehenge was constructed. Diligent research uncovers that Alfred Nobel added a secret codicil to his will, a prize for the Nobel laureate who solves the mystery of Stonehenge.

Weaving together a wealth of primary sources — photos, letters, wills — The Stonehenge Letters tells the tale of a fascinating secret competition.

Praise for The Stonehenge Letters:

'This little novel is a delight from its first word to its last. The Stonehenge Letters is by turns thoughtful, whimsical, haunting and laugh-out-loud funny. Reading this book was like skating over the smoothest ice; I was blissfully unaware of the transition from history to fiction and back again'
— Annabel Lyon, author of The Sweet Girl

'In his alarmingly smart and dangerously absorbing Freud-tinged romance/detective story, Harry Karlinsky deploys explosions, earthworms, radioactive particles and a passel of Nobel laureates to reinvent history in the golden age of invention.'
— Zsuzsi Gartner, author of Better Living Through Plastic Explosives

Another geologist's view of the bluestone problem

There was a very interesting talk last evening from Sid Howells, who works as a geologist with Natural Resources Wales.  It was in Moylgrove Village Hall, where Prof MPP and I have also held forth in past months -- and was on the topic of Geology and Scenery in NE Pembrokshire.

It was a wide-ranging and thoroughly entertaining talk with some excellent slides, and Sid was not afraid of entering the bluestone debate.  He mentioned the rival theories (and the rival books!), and came down very strongly on the side of Occam's Razor, saying that as far as he is concerned we have to assume that the stones were transported by glacier ice for at least most of the way to Stonehenge, since that's the way the hard evidence on the ground points -- unless the archaeologists come up with some very powerful evidence to suggest otherwise.

It's good to see that there are other geologists around who tend to interpret features (including erratic occurrences) as probably natural phenomena, unless there is clear evidence relating to human involvement.  And it's good to see that there are still earth scientists in Wales who trust their own professional judgment and who are not beholden in any way to the archaeological establishment or the media!

Changes coming......

Dear Bloggers and Followers,

There have been problems with this blog for a while, mainly connected to the search facility (which was worse than it is now, but is still not working as it should) and the "share buttons" which are effectively blocked out by some unintended lettering that I can't get rid of. 

Blogger informs me that the template I use for the blog is incredibly old-fashioned and out of date, and that it is no longer "supported" technically.

So time for a change -- please expect the blog to have a totally different appearance before too long -- I hope without any reduction in its readability and its value to readers.  I'm currently trying out some of the newer Blogger templates.

Watch this space....


Monday, 28 April 2014

Rhosyfelin and some heavy symbolism....

A mystery photo of a coffin under a black shroud....  would somebody like to think of a suitable caption?

The other Rhosyfelin rhyolite outcrops

In addition to the main Rhosyfelin rock ridge, adjacent to the archaeological dig site, there are a number of other rhyolite outcrops in the valley, some of them quite prominent.

The photo above shows one of these outcrops, to the SSE of the main ridge, and about 100m up-valley.  I think this has been referred to as "sampling point number 11" by Richard and Rob.  The crag is not a very big one, but it illustrates how important slope processes are here.  On the downslope side of the crag there are occasional exposures of bedrock, but the main features of interest, to a geomorphologist, are the slabs of bedrock that have broken off and rolled or slid down the slope, to end up resting on the valley floor.  there are five or six of these big elongated slabs, including the two shown in the foreground of this pic.

Some of the rocks that started off higher up the slope and ended up lower down have probably moved very slowly indeed, over many thousands of years, simply by being incorporated into slope debris moving inexorably downhill under (initially) periglacial slope processes and later under temperate-climate solifluxion processes. 

Message?  Big stones and slabs move downhill, especially if there is a good gradient, occasionally ending up 50m or more from their places of origin, so long as there is nothing obvious to stop them....

Sunday, 27 April 2014

Rhosyfelin -- going and almost gone.....

Further to my earler post:

Here are two photos taken while I was grovelling about among the gorse bushes on top of the rocky ridge the other day.  The highest part of the crag here is fairly stable solid rock, but next to it there are five (I think -- it's difficult to count because of all the gorse bushes) large detached slabs, all in rather precarious positions and ready to crash down.  If they fall, they will end up very close to where the famous "abandoned orthostat" is -- although it is possible that the latter fell onto a snowbank and slid to its present position.

Another plea to Rob and Richard -- can we have some samples please, from these loose blocks and from the "abandoned orthostat" so that we can see whether they are indeed closely related?

Rhosyfelin -- the next tourist honeypot?

The new parking area at Rhosyfelin is a couple of hundred yards away from here, round the corner at the top of the hill

Thanks to Tim Daw for pointing out this notice that was obviously stuck up on a post near Craig Rhosyfelin in the autumn.  The post is still there, but the notice has disappeared.  Who put it up?  No idea -- it could have been the National Park or Pembs CC.  Anyway, the work to which the notice refers has now been done, and there is a sizeable layby on the road that runs down from the Brynberian Village Hall towards the crags and the ford.  It has room for maybe six or seven cars -- all based upon the wise (or very foolish) advice that the site now has international importance........ hmmm -- I wonder who provided the local authority with that "archaeological advice"?  Phil Bennett or Peter Crane?  Easily led, both of them......

That work will have cost quite a few thousands of pounds in these straightened times, and work is also under way to make improvements to the footpath that runs from the road at the top of the hill down towards the crags.  What next?  Information panels of dubious worth?  How about a Visitor Centre?  (The house next to the gate which allows access to the dig site is currently on the market.... for £250,000.)

Watch this space for further developments......


Tim has kindly posted this transcript on his blog:

Craig Rhosyfelin Visitor Management Proposal

Craig Rhosyfelin Visitor Management Proposal; December 2013
The rock outcrop at Craig Rhosyfelin has recently been confirmed as one of the sources of the inner circle of bluestones at Stonehenge. The archaeological advice we have received has confirmed that this site is now of international importance and is highly likely to generate a great deal of public interest and a steady stream of visitors to the site, especially given the proximity of Pentre Ifan cromlech, another heritage attraction dating from the same Neolithic period. Cadw, who manage Pentre Ifan have a concealed visitor counter which records an average of 25,000 visitors a year. Craig Rhosyfelin is fully expected to generate significant visitor numbers in its own right as well as spin off visits from the nearby Pentre Ifan. In anticipation of the rise in popularity of the site and the inevitable influx of visitors in the short term there is a need to manage the additional traffic that will be generated.

As you will be aware although Craig Rhosyfelin is only less than a mile from the B4329, it is comparatively difficult to gain access to due to the approach roads being steep, twisting and narrow with few passing places and a deep ford. Due to the potential for traffic congestion and vehicles being parked in gateways we have been in discussion with the highway authority, Pembrokeshire County Council to consider a range of traffic management options. In order to be able to respond positively and responsibly to the public’s desire to visit this site, we feel it is necessary to identify a suitable parking area as close to the site as possible.

The site is best approached from the west to avoid the narrowest section of road and ford so we have identified a suitable parking area approximately 300 metres along the road from Craig Rhosyfelin where there is sufficient width of carriageway and verge to accommodate roadside parking. The location of the Parking area is shown on the attached plan (missing). The stretch of verge is to be found on the northern side of the road and is approximately 40 metres in length. The roadside parking would therefore be very similar to that at Pentre Ifan.

We propose to undertake work in the new year so that the parking area will be available for the main visitor season. In the short term it would still be our intention to keep the site as low key as possible and not actively promote it. Our strategy is to be able to respond positively and esponsibly to visitors’ requests by providing information in terms of how best to access the site, where to park and not to obstruct farm and field gateways. We will also be improving the public footpath that runs past the rock outcrop and gives access to the site.

(Copy of public notice posted at site). Posted by Timothy Daw at Sunday, April 13, 2014

Rhosyfelin Foliation Plane

Thanks to Rob and Richard (whose papers I have been re-reading), and thanks to our mysterious friend Myris, I have been trying to get my head around the geology of Rhosyfelin.  I think I am getting there.

As I now understand it, the flattish rock face at Rhosyfelin, which runs away into the distance, coincides with the main "foliation plane" along which the foliated rhyolites with Jovian fabric are exposed.  Sampled point number 8 is just on the left edge of the photo, in the foreground -- but rocks with very similar fabric are exposed all the way along this face.  If there are thin sections of samples from other points along the face, we look forward to seeing them in due course, and to seeing how much lateral variation there may be in the fabric.  If the fabrics are very similar all the way along the 60m or more of the rock face, I am a bit mystified as to why the geologists said that they were now able to fix the provenance of some of the Stonehenge rhyolitic debitage to within a few metres.  Maybe there is more to come on this, in future articles.

The joint planes and fractures (on many different scales) that run into the rock face are at about 90 degrees to the face itself, and as suggested in a previous post: 

As mentioned in that post there are other big fractures that can be followed along the rock face, running more or less horizontally if you look at the strike but with a dip down towards the SE -- ie approx 90 degrees from the sloping rock face.  If you scrabble about on the ridge crest, as I have done, you can pick up some of these sloping surfaces.

Because the foliation plane has given rise to a major structural weakness in the rocks at this site, debris of all shapes and sizes has peeled away from it and has gathered in the litter / scree which is now being investigated with such enthusiasm by the archaeologists --  who are of course desperate to see everything as "quarry" debris.........

The interesting thing for me, arising out of all of this, is that the foliation plane in question runs deep into the earth beneath the area where the archaeologists have been digging and once ran high up into the air above the remnants of the present day ridge.  What this means, in turn, is that the rhyolite fragments at Stonehenge might well have come from a part of the ridge which was once many metres above the present-day ridge crest.  As I mentioned in my SCRIBD article some time ago, the "proto-Rhosyfelin" might well have looked very different from the ridge of today, having been whittled away by glacial, fluvio-glacial and periglacial processes over something like half a million years.

(Note -- if you look at the SCRIBD article, you may well get pretty angry with masses of adverts plastered all over it.  That's something SCRIBD has started doing -- but there should now be a mechanism on your computer which enables you to go to "Ad Choices" and turn all these nuisance adverts off.)

Saturday, 26 April 2014

Corbelled chambers

One of Tim Daw's excellent photos from his "Neolithic" burial chamber at All Cannings.  There is a whole gallery of photos here:

and here we have much more info about Tim's project:

This is another nice illustration of the way in which the seven chambers are being constructed:

The technique is not quite "dry stone corbelling" because there is a lot of concrete used, out of sight, on the outside of each dome.  The flattish stone slabs are also much more standardised in shape and size than those used in corbelled chambers constructed in the Neolithic.  Health and safety, and cost, have obviously had an influence on the methods used by the builders.......  But it's great to see this piece of engineering skill being used again, and for a practical purpose.

For comparison, here are some other corbelled chambers:

Knowth in Ireland, made with much larger flattish slabs

L'Ile Carn in Brittany, made with a collection of stones of all shapes and sizes.  It's a miracle that it still stands after all these years.......

Newgrange in Ireland -- also made with large flattish slabs to provide considerable stability.  No concrete, but small stones used as packing...

This photo of from the inside of one of the Sardinian Bronze Age "proto-castles" called "nuraghi" -- very similar indeed to the one being built by Tim and his friends in Wiltshire.

Friday, 25 April 2014

Rhosyfelin -- a plea for cosmogenic dating

I have pleaded on many occasions for some bright young researcher -- or even EH itself -- to initiate a programme of cosmogenic dating at Stonehenge, so that we can see, once and for all, how old or fresh the various surfaces of the sarsens and the bluestones actually are.  That might resolve many of the issues that we are all arguing about.

Now here's another plea -- direct to MPP and his team.  Please use some of the dosh paid over by the taxpayer to get a series of cosmogenic dates for Rhosyfelin.  It would be fascinating, for example, to know how old the rock outcrop surface is in the photo above -- it looks very old and weathered.

Sadly, parts of the rock face have been smashed up by all the heavy machinery and enthusiastic archaeologists digging here over the past 3 years, and so some parts of the rock face are no longer suitable for sampling.  But there are plenty of other surfaces that should be dated -- for example the upper and lower surfaces of the "orthostat that got left behind"; the top of the crags above the rock face; the rock face itself -- various locations;  and even some of the erratic boulders dug up from the till layer at the bottom of the sediment sequence.  And another plea -- please pull in a geomorphologist -- maybe somebody like Prof Mike Walker from Lampeter -- who could advise on which cosmogenic dating techniques to use and how a sampling programme should be organized.

Come on now -- you know it makes sense.......

Here are some other bits that should be dated:

Fractures at Rhosyfelin

This photo shows the planar foliation and rather tightly spaced fractures (coinciding with narrow quartz bands?) on a projecting slab of bedrock, in the middle part of the Rhosyfelin rock face.

I'm a bit confused by this photo, because Myris said in a post the other day that the foliations at Rhosyfelin run at 90 degrees from the orientation of the vertical crack which  I featured in an earlier post.  The foliations in this photo run parallel with that crack.  We can't actually see the foliations in this pic, but surely they do not run horizontally here-- ie across the alignment of the fractures or pseudo-bedding? (These are not beds because this is not a sedimentary rock but a metamorphosed igneous one.....)

Can we please get some enlightenment here from Myris, or Richard, or any other geologist?

Tysfjord, Norway

This is a wonderful photo (click to enlarge) of Tysford in Norway (which I assume means "Quiet Fjord").  This is one of the most spectacular illustrations I have seen of an intensely scoured glacial landscape.  Look how bare and rounded the fjordsides are.  The "horn" on the right side of the photo still has a little plateau remnant stuck on top of it -- and even on the flanks of this peak there are no great accumulations of scree -- the rapidly flowing ice of the Devensian Glaciation has swept almost all of the loose debris away.

The steep mountain is called Stetind.  The fjord itself is the second deepest in Norway, almost 3,000 feet deep at its deepest point -- this attests to a great deal of ice pouring out from the Scandinavian Ice Sheet towards the Atlantic Ocean.  Tysfjord is inside the Arctic Circle, not far from the Lofoten Islands.

Of course some people want to climb Stetind -- altitude 1392m.  Here is a climbing pic...... makes me giddy just to look at it!

Wednesday, 23 April 2014

Devensian survivals and "landscape zones" in Pembrokeshire

This photo shows Maiden Castle and Lion Rock, near the Trefgarn Gorge (which carries the A40 road) between Haverfordwest and Fishguard.  The rocks are very fragile and very precarious -- and it is doubtful, in this geographical situation, that they could have survived over-riding by the Irish Sea Glacier during the Devensian.  So the suggestion is that central Pembrokeshire remained ice-free around 20,000 years ago, as shown on my latest ice edge map. 

In contrast,  the monadnocks or upstanding rocky hill masses of the St David's Peninsula are much more heavily eroded, as we see here (the two photos are of Carn Llidi, near St David's):

Up on the summit of Carn Llidi, and on nearby Penbiri, and on St David's Head itself, there are extensive ice-smoothed rock surfaces, as we see in the lower photo.  So the ice streaming across this area must have been thick and quite active.

The northern tip of the Pencaer peninsula was also moulded by streaming ice, as we see in this photo from near Carregwastad (where the French landed during the "last invasion" of 1797).  Notice the generally scoured appearance of the cliffs and the landscape inland, and the rounded off or smoothed profiles of the hills:

Closer to the ice edge, as for example in the Dinas - Newport - Carningli area, things are much more complex, with some ice-smoothed surfaces and some quite delicate features that look too fragile to have survived very active glaciation.  Here is one of the glaciated slabs on Garn Fawr, on Dinas Mountain -- as fine a feature as you will find anywhere in the world:

And here is another, from Carningli above Newport:

And here is the area of glaciated slabs at Carn Meini, adjacent to what used to be called "the bluestone quarry":

Are these slabs in these widely spaced locations all of the same age?  Cosmogenic dating is seriously needed........

Another fascinating difference between Carn Llidi and Carningli is the lack of a big scree bank at the former and a very substantial scree bank on the lee (south) side of the latter:

So the explanation must be that there was a prolonged period of ice erosion at the former site, but just a short one at the latter site, maybe with marginal ice melting more or less balancing the rate of ice advance.  Maybe there was a windscoop here, within which periglacial slope processes were able to operate at or near the peak of the glacial episode.

So we have three Devensian landscape types in Pembrokeshire:

1.  An area beyond the ice edge where fragile landforms were able to survive -- but where there will have been extensive snowfields and where periglacial processes operated for many thousands of years. (For example, the Trefgarn Gorge area)

2.  A zone maybe 5 kms wide across which the Devensian ice edge oscillated around 20,000 years ago, with some fragile features surviving, some glacial erosional features created or freshened up, and banks of scree able to accumulate in places. (For example, the area around Carningli and Carnedd Meibion Owen)

3.  An area well inside the maximum position of the ice edge, where erosional processes were able to operate, where fresh scree was not able to accumulate, and where the landscape was rounded off or smoothed. (For example, the hill masses at the NW corner of the St David's Peninsula)

Gradually it is all coming together.  Work in progress.....

Tuesday, 22 April 2014

Quartz blocks at Rhosyfelin are not erratics

There are several big blocks of quartz low down in the sedimentary sequence at Rhosyfelin, which I have previously interpreted as erratics transported into the area along with other foreign stones and boulders.  Well, I have had a change of opinion on this.  Now, following the completion of the 2013 dig, one can see that the biggest block actually seems to be sitting on an outcrop of quartz bedrock.  So there must be a big mass of it incorporated into the rhyolites.  Perhaps Rob or Richard will tell us if this is typical --  maybe it is a secondary feature, formed some time after the rhyolites were laid down?

I must admit to having been a bit worried about the "fresh" appearance of the quartz blocks, with few signs of abrasion and many sharp edges.  This would be consistent with the blocks having travelled hardly at all from their place of origin.

A bit more digging in 2014 will reveal whether this is really the bedrock floor in the digging area, and how thick the sediments are beneath the lowest digging surface from 2013, as shown in my posts of last September.

On the significance of Rhosyfelin Locality 8

 The Craig Rhosyfelin area, showing the grid of sampled points referred to by Ixer and Bevins

Having been out to look at Rhosyfelin again yesterday, it's not a bad idea to look again at this statement:

Quote from Ixer and Bevins 2011
"This is the first time that any lithics from Stonehenge have been unequivocally assigned to an area of a few square metres, namely to within a very small single outcrop or couple of outcrops......"
Rob Ixer and Richard Bevins, Archaeology in Wales 50, 2011, pp 21-31

This implies that Locality 8 on the air photo is actually the source of the "rhyolite with fabric" found in the Stonehenge debitage.  It also explains why Mike Parker Pearson and his colleagues have become so obsessed with the idea of the "Rhosyfelin Quarry" -- in the conviction that the geologists have given them the "all clear."

However, the geology is not that simple, and I have previously questioned the reliability of  that statement made by Rob Ixer and Richard Bevins.
I have argued that without a rather dense sampling grid, it would be a mistake to argue that the "foliated rhyolite with Jovian fabric" matched up with Stonehenge samples is restricted to the one site (locality 8) at the NE tip of the Rhosyfelin rocky ridge.  The geologists don't know where else this particular rock type might outcrop -- or if they do know they haven't given the evidence to support the contention.

 Strong planar foliation shown on the side of a detached block in the Rhosyfelin "litter" beneath the rock face.  Some fractures run parallel with this foliation, and others cut across it

One problem I have with the evidence as presented is that we do not see (in the Archaeology in Wales paper) the thin section slides for the other localities, so we have nothing to compare with locality 8 or with the samples from Stonehenge.  What we do have are these 3 illustrations:

 Jovian fabric -- locality 8

 Jovian fabric -- Stonehenge debitage

 Jovian fabric -- Stonehenge debitage near Heelstone

 Bear in mind that one of these illustrations is at a slighly different level of magnification than the other two.  In the Heelstone sample, the black blobs look like little fishes or tadpoles -- and they do not look like this in the other slides.  In the other Stonehenge sample there are fewer black blobs and they are less elongated, and the other components in the slide look almost liquid rather than crystalline.  The locality 8 sample is different again, with a greater density of black blobs and with much more irregular shapes.  To my untrained eye, these three fabrics do not look identical, but they are similar, suggesting that they are part of a continuum, and in my view it is quite possible that the Stonehenge samples have NOT come from the few square metres around locality number 8.

I would be more convinced if we had at our disposal the thin section slides showing us the fabric at all the other sampling points identified on the air photo.  How different, or how similar, are they to the three slides shown above?  At one point I recall Rob referring to locality 9 as the possible source of some of the Stonehenge debitage.......... was that a mistake, or was that at one time a working hypothesis, later changed when the slide from locality 8 had been examined?

So if the area of foliated rhyolite with Jovian fabric is more extensive, where might other outcrops be located?  Here is a photo of the rock face:

The Rhosyfelin rock face, after clearing by the archaeology team.  According to the grid of geological sampling points, no samples have been taken from anywhere along this face.

Rob tells us that the crack featured in my last post is 90 degrees away from the direction of the foliations.  We have to work in three dimensions here -- and this means that either the foliated band  sampled at point 8 runs as a very thin band all the way along this face and might outcrop in other localities in the Rhosyfelin - Pont Saeson area, or else it runs more or less parallel with the rock face, either along the cliffline itself, or some distance outside it or some distance within it.  Such a "sheet" (we cannot call it a bed) could run deep into the ground and could have been exposed much higher up than the current crest of the ridge.  In other words, bits and pieces of it could have been carted away from this general area by overriding ice at a time when the landscape had a rather different appearance from the Rhosyfelin of today.

We need more geological info here, chaps........ is it in the publication pipeline?


I have just found this thin section slide from one of the other geology papers by Rob and Richard.  It's from Point 10, quite a way to the south of the rock ridge where the archaeologists have been working and over 200m from Point 8.  Is this also a part of the same "rhyolite with fabric" continuum?  There are strong similarities with the slides shown above, except for the absence of the prominent black blobs.


Monday, 21 April 2014

Rhosyfelin-- the famous crack

There are lots of photos flying around which show clusters of earnest ladies and gentlemen gazing intently at this crack in the rock face at Rhosyfelin, having things explained to them by either Richard Bevins or Mike Parket Pearson.  I assume, therefore, that this is where the samples came from which have been matched up accurately with the debitage collection from Stonehenge.

However, to extend that geological work into an assumption that this is where at least one of the Stonehenge orthostats came from is taking things too far.  For a start, this crack is no more than 30 cms wide, and there is no way that a viable orthostat could have come out of that crack -- or "alcove" as it is described by some people.  Possibly small lumps of stone might have been taken for here, for the manufacture of tools.

But if an orthostat (or two) did travel from here to Stonehenge, by some means or other, it must have come from a slab of rock closer to the camera, which has now been entirely removed, or else from a slab of rock higher up, above the top of the current rock face.  The fractures here -- and the foliation -- run almost vertically.  So could the rock that found its way to Stonehenge have come from ten feet higher up?  Twenty feet higher?  Thirty feet higher?  It would be good to get a geological view on this -- leaving archaeology entirely to one side -- from either Rob or Richard.  Over to you, chaps.....

Rhosyfelin "hammerstones" -- seek and thou shalt find...

I've done a previous post on the occurrence of rounded pebbles at Craig Rhosyfelin, and today I wandered along the river bank for a few minutes,  looking for things that archaeologists, in their infinite wisdom, might refer to as "hammerstones."  I found four very quickly, on the river bed and upstream of the Rhosyfelin dig site.  The pebbles have all come from the till and fluvio-glacial gravels exposed in the river banks. I am sure that similar pebbles -- and many rounded stones that are larger and smaller then the ones in the photos -- also occur in the till and in the overlying deposits investigated by the archaeologists.

Let's think straight here.  The occurrence of stones like these in the sediments exposed during "The Rhosyfelin Quarry Hunt" does not prove that there was a quarry here.  However, some of the stones could well have been discovered by past inhabitants of the site and used for breaking or shaping stone.  Also, we cannot preclude the possibility that past inhabitants might have collected rounded stones from the banks of the river and used these as hammerstones at the camp site being investigated. 

All the "convenient" stones I have seen and collected are entirely natural, and require no human intervention at all when it comes to explaining why they are where they are.

Even if some of the "hammerstones" have genuine percussion marks on them,  that does not prove that they were used in quarrying operations designed to obtain large stones for transport to Stonehenge.  They are much more likely to have been used in local tool-making, or for crushing animal bones, beating fibrous plants or crushing fruit.

The source of the Rhosyfelin "orthostat"

At great personal risk, in the cause of science, I climbed up through the gorse bushes this afternoon and took a look at the crag immediately above the 'abandoned orthostat'.  This is how it looks from the other side of the ridge.

Immediately to the left of the highest crag, near the left edge of the photo, you can see the detached blocks which haven't quite got round to crashing down on top of the hard-working archaeologists thus far. But they are a tough lot, and very dedicated to the task in hand -- rumour has it that they will be back in September.  I hope they wear their hard hats............

April at Rhosyfelin

I spent a very pleasant Bank Holiday afternoon at Craig Rhosyfelin, "doin' a bit o' geomorfin'."  (That's how the Royal Navy personnel on HMS Protector referred to the work being done by David Sugden and myself in the South Shetlands in 1965-66.)

Plenty of images to share, and I'll probably do a number of posts about my new observations.  But to start with, here is a rather nice image of the rock face -- taken straight into a late afternoon sun.  Excellent shadows which bring out the edges of the slabs of rhyolite.  You can see the "abandoned orthostat" in its black plastic shroud, awaiting the return of the diggers in September 2014.    Not exactly beautiful -- and in fact rather spooky......

But you can see the prominent crag about 35 feet above where the big stone finally came to rest.  I have always thought that this crag is the source of the big stone -- so I climbed up and fought my way through gorse bushes to have a look at it.  This confirmed my belief, and I was interested to find five other big stones up there, in quite precarious positions, ready to crash down, when the time is right, in the general direction of the black plastic monstrosity. 

So the crag is now in an advanced state of decay, and it seems entirely reasonable to conclude that during the thousands of years of periglacial climate at the end of the Devensian glacial episode, frost action did the job of loosening these blocks.  Other loosened blocks actually fell down the rock face.  Now, with the advent of a full interglacial climate, biological processes have taken over, and it may be that the roots of gorse bushes and small trees will widen cracks and contribute to the next set of rockfalls.  Maybe archaeologists and JCBs will accelerate the process.......